Patent Application
20050113798
The invention relates to the treatment and correction of venous insufficiency. More particularly the invention relates to a minimally invasive procedure using a catheter-based system to treat the interior of a blood vessel. The invention has particular application to varicose veins although it is not limited thereto.
The human venous system of the lower limbs consists essentially of the superficial venous system and the deep venous system with perforating veins connecting the two systems. The superficial system includes the long or great saphenous vein and the short saphenous vein. The deep venous system includes the anterior and posterior tibial veins which unite to form the popliteal vein, which in turn becomes the femoral vein when joined by the short saphenous vein.
The venous systems contain numerous one-way valves for directing blood flow back to the heart. Venous valves are usually bicuspid valves, with each cusp forming a sac or reservoir for blood which, under pressure, forces the free surfaces of the cusps together to prevent retrograde flow of the blood and allow antegrade flow to the heart. An incompetent valve is a valve which is unable to close because the cusps do not form a proper seal and retrograde flow of blood cannot be stopped.
Incompetence in the venous system can result from vein dilation. Separation of the cusps of the venous valve at the commissure may occur as a result. Two venous diseases which often involve vein dilation are varicose veins and chronic venous insufficiency.
The varicose vein condition includes dilatation and tortuosity of the superficial veins of the lower limb, resulting in unsightly discoloration, pain and ulceration. Varicose veins often involve incompetence of one or more venous valves, which allow reflux of blood from the deep venous system to the superficial venous system or reflux within the superficial system.
Varicose veins are compatible with long life and rarely cause fatal complications, but the condition significantly decreases the quality of life. Patients complain primarily of leg fatigue, dull, aching pains, ankle swelling and ulcerations. Occasionally, thrombosis occurs in dilated subcutaneous channels, resulting in local pain, induration, edema, inflammation, and disability. In addition to those problems, the high visibility of the unattractive rope-like swellings and reddish skin blotches causes considerable distress for both men and women. Lastly, varicose eczema, which is a local reddened swollen and itching skin condition can occur and can spread to distant parts of the body (called an “Id reaction”).
Phlebosclerosis, the destruction of venous channels by the injection of sclerosing agents, has been used to treat varicose veins since 1853, when Cassaignae and Ebout used ferric chloride. Sodium salicylate, quinine, urea, and sodium chloride have also been used, but the agent more recently favored is sodium tetradecyl sulfate. In order for phlebosclerosis to be effective, it is necessary to evenly dispense the sclerosing agent throughout the wall of the vein without using toxic levels of the sclerosing agent. This is not particularly difficult for the smaller veins. However, it is quite difficult or nearly impossible in larger veins. When a larger vein is injected with a sclerosing agent, the sclerosing agent is quickly diluted by the substantially larger volume of blood which is not present in smaller veins. The result is that the vein is sclerosed (injured) only in the vicinity of the injection. If the procedure is continued, and the injections are far apart, the vein often assumes a configuration resembling sausage links. The problem cannot be cured by injecting a more potent solution of sclerosing agent, because the sclerosing agent may become toxic at such a concentration.
U.S. Pat. No. 5,676,962 discloses an injectable micro foam containing a sclerosing agent. The microfoam is injected into a vein where it expands and, theoretically, achieves the same results as a larger quantity of sclerosing agent without the toxicity. Such foam is presently manufactured under the trademark Varisolve® by Provensis, Ltd., London, England. Recent clinical trials of the foam indicate a success rate of 81%.
Until recently, the preferred procedure for treating the great saphenous vein was surgical stripping. This highly invasive procedure involves making a 2.5 cm incision in the groin to expose the saphenofemoral junction, where the great saphenous vein and its branches are doubly ligated en masse with a heavy ligature. The distal portion of the vein is exposed through a 1-cm incision anterior to the medial malleolus, and a flat metal or plastic stripper is introduced to exit in the proximal saphenous vein. The leg is held vertically for 30 seconds to empty the venous tree before stripping the vein from the ankle to the groin. If the small saphenous vein is also incompetent, it is stripped at the same time from an incision posterior to the lateral malleolus to the popliteal space. After stripping the veins, the leg is held in the vertical position for three to four minutes to permit broken vessel ends to retract, constrict, and clot.
After the stripping procedure, collateral veins are removed by the avulsion-extraction technique. By working through small (5 to 8 mm) transverse incisions, segments of vein 10 to 20 cm long can be removed by dissecting subcutaneously along the vein with a hemostat, and then grasping, avulsing, and removing the vein. With practice, long segments of vein in all quadrants can be removed through these small incisions. No attempt is made to ligate the branches or ends of the veins, since stripping has shown it to be unnecessary. Bleeding is controlled by elevation and pressure for two to four minutes. As many as 40 incisions are made in severe cases, but their small size and transverse direction permit closure with a single suture.
Before closure of the incisions, a rolled towel is rolled repeatedly from the knee to the ankle and from the knee to the groin to express any clots that may have accumulated. The groin incision is approximated with three 5-0 nylon mattress sutures and all other incisions are closed with a single suture.
As can be readily appreciated, the stripping and avulsion-extraction procedures are relatively invasive and require significant anesthesia. It can therefore be appreciated that it would be desirable to provide an alternative, less invasive procedure which would accomplish the same results as stripping and avulsion-extraction.
Recently, a number of patents have issued disclosing the treatment of varicose veins with RF energy. Illustrative of these recent patents are: U.S. Pat. No. 6,200,312 entitled “Expandable Vein Ligator Catheter Having Multiple Electrode Leads”; U.S. Pat. No. 6,179,832 entitled “Expandable Catheter Having Two Sets of Electrodes”; U.S. Pat. No. 6,165,172 entitled “Expandable Vein Ligator Catheter and Method of Use”; U.S. Pat. No. 6,152,899 entitled “Expandable Catheter Having Improved Electrode Design, and Method for Applying Energy”; U.S. Pat. No. 6,071,277 entitled “Method and Apparatus for Reducing the Size of a Hollow Anatomical Structure”; U.S. Pat. No. 6,036,687 entitled “Method and Apparatus for Treating Venous Insufficiency”; U.S. Pat. No. 6,033,398 entitled “Method and Apparatus for Treating Venous Insufficiency Using Directionally Applied Energy”; U.S. Pat. No. 6,014,589 entitled “Catheter Having Expandable Electrodes and Adjustable Stent”; U.S. Pat. No. 5,810,847 entitled “Method and Apparatus for Minimally Invasive Treatment of Chronic Venous Insufficiency”; U.S. Pat. No. 5,730,136 entitled “Venous Pump Efficiency Test System And Method”; and U.S. Pat. No. 5,609,598 entitled “Method and Apparatus for Minimally Invasive Treatment of Chronic Venous Insufficiency”. These patents generally disclose a catheter having an electrode tip which is switchably coupled to a source of RF energy. The catheter is positioned within the vein to be treated, and the electrodes on the catheter are moved toward one side of the vein. RF energy is applied to cause localized heating and corresponding shrinkage of the adjacent venous tissue. After treating one section of the vein, the catheter can be repositioned to place the electrodes to treat different sections of the vein.
Although this procedure has gained acceptance and is less invasive than the stripping and avulsion-extraction procedures, there are several disadvantages to it. In particular, RF treatment is actually quite slow and painful and the patient must be sufficiently anaesthetized along the entire length of the veins to be treated. In addition, repositioning the catheter is time consuming thus requiring anesthesia for a prolonged period. Moreover, the RF treatment is incomplete, as only a portion of the vein wall is actually treated, i.e. the portion contacting the electrode. The partially treated vein may eventually recanalize. Furthermore, tributary veins remain unaffected and must be treated separately. In addition, for even and consistent cauterization, RF treatment requires that the practitioner be keenly aware of the procedure time. If RF energy is applied for too long, it can cause undesired burns. If RF energy is not applied long enough, the treatment is ineffective.
In addition to RF treatment, laser treatment has been used with some success. Laser treatment shares many of the disadvantages of RF treatment. In particular, as with the RF devices, the practitioner must be very careful as to the intensity and duration of the treatment to assure that the treatment is effective but without causing undesired burns.
Parent application Ser. No. 09/898,867 discloses an apparatus for delivering an intravascular drug such as a sclerosing agent (or a microfoam sclerosing agent) to a varicose vein. The apparatus includes a catheter having three concentric tubes. The innermost tube has a guide wire lumen and an inflation lumen. The distal end of the innermost tube has an integral inflatable occlusion balloon in fluid communication with the inflation lumen. The intermediate tube has a lumen through which the innermost tube extends. The distal end of the intermediate tube has a self-expanding balloon with a plurality of fluid pores in fluid communication with the intermediate tube lumen. The outer tube has a lumen through which the intermediate tube extends. Sclerosing agent is dispensed through the intermediate tube to pores located at the distal end of the intermediate tube or in the self-expanding balloon. Veins are sclerosed as the self-expanding balloon is pulled through and ultimately out of the vein.
While particular methods and apparatus were disclosed in the parent application for occluding the blood vessel, dispensing sclerosing agent, and locating tributaries, it will be appreciated that it would be desirable to have additional manners of accomplishing the same.
In accordance with the present invention, an apparatus is provided which includes a catheter device having three concentric tubes: an inner tube, an outer tube, and an intermediate tube. Each tube has a proximal end and a distal end with a lumen extending therethrough. As used herein, the term proximal means closest to the practitioner and the term distal means farthest from the practitioner when the apparatus is in use. An inflatable balloon is located at or near the distal end of inner tube and a fluid valve is coupled to the proximal end of the inner tube. The balloon is inflated by injecting fluid through the valve and is held in an inflated condition by closing the valve. A fluid outlet is located at or near the distal end of the intermediate tube and a “plunger” or piston is coupled to the proximal end of the intermediate tube. The plunger is movable within the outer tube defining a fluid reservoir of varying size between the proximal end of the outer tube and the plunger. The plunger permits fluid communication between the fluid reservoir and the lumen of the intermediate tube. The proximal end of the outer tube is provided with a trifurcated fitting including a Touhy-Borst type connector. The proximal end of the inner tube extends through the Touhy-Borst connector which provides a fluid seal between the inner tube and the outer tube and which locks the inner tube in position relative to the outer tube. A pullwire is coupled to the plunger and extends through a central port of the trifurcated fitting which maintains a fluid seal between the pullwire and the outer tube. The third port of the trifurcated fitting is provided with a female Luer with a check valve which permits one-way fluid access into the fluid reservoir. According to one embodiment, the distal end of the inner tube is provided with a radiopaque tip and a safety wire extends within the inner tube providing the inner tube with stiffness and maneuverability for precise placement of the inflatable balloon. The wire is bonded to or captures the entire device, thereby helping to keep it together. The outer tube may be transparent and provided with a plurality of movable exterior markers which are useful in performing the methods of the invention.
According to alternate embodiments of the apparatus, other types of tracking devices may be used at the tip of the inner tube rather than the radiopaque tip. Examples of such devices include an LED or an illuminated fiber optic which is visible through the skin, or a magnet which can be detected with an electromagnetic sensor.
Methods of the invention include examining the patient and marking the patient's leg to indicate the entry site, the occlusion site and important sites (e.g. tributaries) along the blood vessel. The distal end of the outer tube is placed adjacent to the entry site and the inner tube and intermediate tube are extended outside the patient along the leg to the occlusion site. The intermediate tube is then drawn back from the occlusion site to the first important site marking proximal of the occlusion site. One of the movable exterior markers on the outer tube is then moved to the position occupied by the plunger. The intermediate tube is then moved to the next proximal important site marking on the leg and another marker on the outer tube is moved to the corresponding position of the plunger. These steps are repeated until all of the important site markings have been recorded with the movable markers on the outer tube. The catheter is then reset so that the distal ends of the inner tube and intermediate tube are adjacent to each other. A 10 cc to 20 cc syringe is loaded with sclerosing agent and is attached to the female Luer. While holding the catheter in an upward direction, 10 cc of sclerosing agent is injected into the fluid reservoir and the intermediate tube until a few drops exit the fluid outlet of the intermediate tube and the tubes are purged of air bubbles. If necessary, the syringe is reloaded with additional sclerosing agent.
The inner and intermediate tubes are then inserted through a hemostasis valve or cut-down into the blood vessel and maneuvered through the vessel until the distal end of the outer tube abuts the vessel or hemostasis valve. The balloon is then inflated using a 3 cc to 5 cc syringe coupled to the proximal end of the inner tube. Infusion of sclerosing agent is commenced by pulling the pullwire so that the plunger is moved proximally forcing fluid out of the fluid reservoir through the intermediate tube and out of the fluid outlets at the distal end of the intermediate tube. When the plunger reaches one of the markers on the outer tube, additional sclerosing agent may be injected using the 10 cc to 20 cc syringe. The plunger is then moved to the next marker and additional sclerosing agent is injected. After all of the markers have been passed by the plunger, the balloon is deflated and the catheter device is removed from the patient.
The occlusion devices of the present invention include: sponges, umbrellas, cages, chemical sealants, ligation, and a suction device. The umbrella or cage designs may incorporate elastic or superelastic struts, a tubular inflatable cuff, or a wire hoop with a basket.
The methods for locating the occlusion device according to the invention include: ultrasound, palpation, fluoroscopic and magnetic resonance imaging, placing a bright light (e.g. LED) at the end of the occlusion device, pressure monitoring, and a technique similar to the placement of a “wedge catheter”.
The methods for locating tributaries include two types: one involves pre-marking on the patient's skin, and the other does not use marking. The pre-marking methods include locating the tributaries via ultrasound, transillumination, or other type of imaging, and marking the patient's skin at the locations of the tributaries. After pre-marking several additional methods can be used. One method involves marking the treating device by placing the treating device on the patient's skin and marking it in locations that align with the marks on the patient's skin. A second method following pre-marking involves using a bright light at the tip of the drug delivery device. A third method following pre-marking involves using ultrasound to locate the tip of the drug delivery device. A fourth method following pre-marking involves using palpation to locate the tip of the drug delivery device. A fifth method following pre-marking involves using a magnet at the tip of the drug delivery device and a magnetic follower on the patient's skin. Several different types of magnetic followers are provided.
The methods for locating tributaries without pre-marking include: ultrasound imaging during the procedure, placing a light source at the tip of the drug delivery device bright enough to illuminate the tributaries through the patient's skin, external illumination with or without an image intensifying system, real time fluoroscopy or other type of imaging, and pressure gradient detection.
Further embodiments of catheter-based treating devices include: a catheter having an atraumatic floppy guide wire tip attached to the distal end of an inflatable occlusion balloon, a dual monorail catheter system, a two-way single monorail catheter system, a two-way clip-on catheter system, and a multi-perforated catheter which does not move during drug delivery.
Additional features and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
In one embodiment of the invention, an apparatus for treating the interior of a blood vessel is provided. The apparatus comprises a first catheter having a proximal end and a distal end with a plurality of spaced apart perforations therebetween, an occlusion device coupled to the distal end of said first catheter, means for deploying the occlusion device, and means for dispensing a treatment agent through said perforations proximal of said occlusion device. The device may further comprise a second catheter movable within said first catheter, said second catheter having at least one perforation adapted to align sequentially with said plurality of said spaced apart perforations as said second catheter is moved through said first catheter, said second catheter adapted to receive a treating agent and dispense the treating agent through said at least one perforation. The apparatus may have an atraumatic tip coupled to the occlusion device. The occlusion device may be a balloon, sponge, umbrella, or sealant dispenser. The balloon may be an inflatable balloon. The perforations may be dimensioned to prevent passage of treating fluid until a predetermined fluid pressure is reached. The apparatus may comprise a coaxial cylindrical baffle located within said first catheter and defining an annular space between it and said first catheter. The apparatus may also comprise an inflatable catheter substantially coaxial with and extending through said first catheter, wherein said occlusion device and inflatable balloon is coupled to said inflation catheter. Said means for deploying includes a first lumen in said first catheter and said means for dispensing include a second lumen in said first catheter. Said first lumen and said second lumen may be coaxial. Said means for dispensing include said second lumen and a third lumen in said catheter, said second and third lumena being coupled at their distal ends. In one embodiment, said first lumen is longer than said second lumen. Said perforations may each have substantially the same diameter. In other embodiments, at least some of said perforations have a different diameter. The perforations may be evenly spaced or variably spaced. Some of said perforations may be provided in spaced apart groups, evenly spaced groups, or variably spaced groups. Each of said groups may contain the same number of perforations or a different number of perforations.
In another embodiment, a method for treating the interior of a blood vessel is provided. The method comprises delivering an apparatus into the blood vessel, the apparatus comprising a first catheter having a proximal end and a distal end with a plurality of spaced apart perforations therebetween, an occlusion device coupled to the distal end of the first catheter and a deployment means for deploying said occlusion device, deploying the occlusion device and dispensing a treating agent through the perforations in the first catheter proximal the occlusion device while maintaining the first catheter stationary. The apparatus may further comprise a second catheter movable within the first catheter, the second catheter having at least one perforation adapted to align sequentially with the plurality of spaced apart perforations as the second catheter is moved through the first catheter, the second catheter adapted to receive a treating agent and dispense the treating agent through the at least one perforation, and said method further comprises withdrawing the second catheter through the first catheter while dispensing treating fluid and maintaining the first catheter stationary.
In another embodiment, an apparatus for treating the interior of the blood vessel is provided. The apparatus comprises a catheter having a proximal end and a distal end, a deployment control member having a proximal end and a distal end and being movable through said catheter, an occlusion device coupled to said distal end of said deployment control member, said occlusion device being deployed by movement of said deployment control member towards said distal end of said catheter and being recaptured by movement of said deployment control member, and means for dispensing a treating agent proximal said occlusion device. Said occlusion device may be a sponge or a plurality of elastic struts covered with a material which effectively occludes the flow of blood. The elastic struts may be superelastic and said material may be a membrane or fine mesh. The occlusion device may also include a cone-shaped membrane with an inflatable cuff.
In one embodiment, of the invention, a method of treating the interior of a blood vessel is provided. The method comprises delivering a catheter through the blood vessel, dispensing an occlusion agent through the catheter, and dispensing a treating agent proximal said occlusion agent. The occlusion agent may be a glue, butyl-cyanoacrylate or a fibrin solution. The method may further comprise applying external pressure to the blood vessel after dispensing the occlusion agent.
In another embodiment, a method of treating the interior of a blood vessel is provided. The method comprises locating an occlusion site along a blood vessel, applying pressure to the occlusion site sufficient to block the flow of blood and dispensing treating agent in the blood vessel proximal the occlusion site. The application of pressure may be accomplished with a mechanical device. The mechanical device may take the form of an inflatable cuff with means for localizing pressure applied external to the occlusion site, a clamp applied external to the occlusion site, a suture applied through a surgical opening, or a clamp applied through a surgical opening. The application of pressure may also be accomplished by applying negative pressure from within the blood vessel.
In another embodiment of the invention, an apparatus for treating the interior of a blood vessel is provided. The apparatus comprises a first catheter having a proximal end and a distal end, an occlusion device coupled to said distal end of said first catheter and a second catheter having a proximal end and a distal end said second catheter being slidable to said first catheter via a monorail coupling, said second catheter being adapted to receive a treating agent and dispense through a port at said distal end of said second catheter and proximal said occlusion device. The apparatus may further comprise a flexible guidewire having a proximal end and a distal end where said first catheter is slidably coupled to said guidewire via a first monorail coupling and said second catheter is slidably coupled to said guidewire via a second monorail coupling. An atraumatic tip may be coupled to said distal end of said guidewire. In some embodiments, said second catheter is directly coupled to said first catheter via said monorail coupling. An atraumatic tip may be coupled to said occlusion device. The second catheter may be directly coupled to the first catheter via the monorail coupling and the monorail may be a clip-on coupling. The occlusion device may be selected from the group consisting of a balloon, a sponge, an umbrella, and a sealant dispenser. The balloon may be an inflatable balloon.
In another embodiment, a method for treating the interior of a blood vessel is provided. The method comprises delivering an apparatus to the interior of the blood vessel, the apparatus including a first catheter having a first proximal end and a distal end, an occlusion device coupled to the distal end of the first catheter and a second catheter having a proximal end and a distal end, the second catheter being slidably coupled to the first catheter via a monorail coupling, the second catheter being adapted to receive a treating agent and dispense it through a port at the distal end of the second catheter, deploying the occlusion device and dispensing the treating agent through the second catheter and proximal the occlusion device while sliding the second catheter away from the occlusion device.
In one embodiment, a method of treating the interior of a blood vessel is provided. The method comprises locating an occlusion site in the blood vessel, locating an occlusion device at the occlusion site, deploying the occlusion device at the occlusion site such that the flow of blood is blocked by the occlusion device and dispensing a treating agent proximal the occlusion device. Locating the occlusion site and locating the occlusion device may comprise using ultrasound imaging, using palpation, using fluoroscopic imaging, using magnetic resonance imaging, or locating the occlusion device by illuminating the inside of the blood vessel. Illumination of the inside of the blood vessel may be performed using an LED or a fiberoptic element. Locating the occlusion site and locating the occlusion device may also comprise using pressure measurements. Use of pressure measurements may be performed by deploying a pressure sensor inside the blood vessel, moving the pressure sensor until an increase in pressure is detected and then moving the pressuring sensor back until a decrease in pressure is detected. Finally, locating the occlusion site and locating the occlusion device may comprise using a wedge catheter.
In one embodiment, a method of treating the interior of the blood vessel is provided. The method comprises locating a catheter within the blood vessel through a venipuncture, dispensing a treating agent through a dispensing port in the catheter while withdrawing the catheter from the blood vessel, locating tributary branches along the blood vessel, locating the catheter at tributary branches along the blood vessel, and dispensing an additional amount of treating agent when the catheter passes a tributary batch. Location of the tributary branches may be performed using ultrasound, x-radiation, transillumination, or magnetic resonance imaging. Locating the catheter at tributary branches may comprise premarking a catheter at the locating of the venipuncture when the dispensing port is located at the tributary branches. Withdrawal of the catheter may comprise withdrawing the catheter from the blood vessel with a pull wire and locating the catheter at tributary branches may comprise premarking the pull wire at the location of the venipuncture when the dispensing port is located at the tributary branches. The locations of tributaries may be marked on the skin of the patient. Locating the catheter may comprise using a light source on the catheter, ultrasound imaging, palpation of the end of the catheter, a magnetic follower, a magnetic viewer, an electromagnetic indicator, or an audible indication. Locating the tributaries and locating the catheter may comprise using ultrasound imaging, using a light source on the catheter, using external illumination, using external IR illumination and an IR viewing device, using real time imaging selected from the group consisting of x-ray, magnetic resonance, and fluoroscopy, or using monitoring fluid pressure at the catheter.
In another embodiment of the invention, a device for treating blood vessels is provided. The device comprises a catheter having a proximal end, a body and a distal end, the body comprising a plurality of elution holes, lumen adapted to provide a fluid pathway from the proximal end of the catheter to the elution holes and an expandable vessel flow blocker located at the distal end of the catheter wherein the total fluid resistance of the elution holes is about equal to or greater than the total resistance of the lumen. The expandable vessel flow blocker may be an expandable balloon or an expandable sponge. In some embodiments, the total fluid resistance of the elution holes is about 125 percent or more than the fluid resistance of the lumen. In some embodiments, the hydraulic diameter of each elution hole is generally less than about 0.010 inches and in other embodiments, the hydraulic diameter is less than about 0.004 inches. The elution holes in some embodiments are generally spaced about 1 centimeter to about 2 centimeters apart. The catheter may further comprise an occluder capable of blocking fluid flow through at least one elution hole. The catheter body may further comprise a side lumen continuous with at least one elution hole, the occluder may be a configurable occluder position within the side lumen. The occluder having a first configuration capable of resisting flow through at least one elution hole and a second configuration capable of allowing flow through at least one elution hole affected in the first configuration. The occluder may comprise a wire. The wire may comprise at least one narrow portion and at least one enlarged portion. In the first configuration, one enlarged portion is occluding an elution hole and in the second configuration the one enlarged portion is not occluding an elution hole. In another embodiment, the occluder comprises an elastomeric cord. The distal end of the elastomeric cord may be engaged to the distal end of the side lumen. The wire may have a polygonal cross-sectional shape such as a square cross-sectional shape. The occluder may also be coated or treated with a lubricant to facilitate movement within the side lumen. In another embodiment, the occluder comprises a hollow elastomeric tube. In the first configuration, the tube is inflated and the tube is deflated in the second configuration. In another embodiment, the occluder comprises at least one covering of the catheter body. The coverings may comprise elastic coverings or movable slits.
In one embodiment, a device for treating blood vessels is provided. The device comprises a catheter having a proximal end, a body and a distal end, the body comprising at least one elution hole, each elution hole having an inflow opening and an outflow opening, a lumen adapted to provide a fluid pathway from the proximal end of the catheter to the outflow openings of the elution holes, and an occluder adapted to block fluid flow through at least one elution hole where the occluder is adapted to affect fluid flow distal to the inflow opening of the elution holes. The occluder may be adapted to affect fluid flow between the outflow openings and inflow opening of the elution holes or it may be adapted to affect fluid flow distal to the outflow openings of the elution holes. Where the occluder is a movable occluder positioned within the side lumen, the movable occluder may have a first configuration capable of resisting flow through at least one elution hole and a second configuration capable of allowing flow through at least one elution hole affected in the first configuration. The occluder may comprise a wire where the wire comprises at least one narrow portion and at least one enlarged portion. In the first configuration, one enlarged portion is occluding an elution hole and in the second configuration the one enlarged portion is not occluding an elution hole. In another embodiment, the movable occluder comprises an elastomeric cord. The distal end of the elastomeric cord is generally engaged to about the distal end of the side lumen. In one embodiment, the wire has a square cross-sectional shape. The occluder may coated or treated with a lubricant to facilitate movement within the side lumen. In another embodiment, the occluder comprises a hollow elastomeric tube where the tube is inflated in the first configuration and deflated in a second configuration. In another embodiment, the occluder comprises at least one covering of the catheter body. The coverings may comprise elastic coverings or movable openings. In one embodiment, the movable openings comprise deflectable openings. In another embodiment, the movable openings comprise slidable or rotatable openings.
In another embodiment, a method of performing sclerotherapy is provided. The method comprises the steps of providing a catheter with an effusion lumen and plurality of elution holes continuous with an effusion lumen. The plurality of elution holes having a total fluid resistance generally greater than the total fluid resistance of the infusion lumen, inserting the catheter into a mammal and injecting a sclerosing agent into the infusion lumen. The inserting step may be performed into a vein of the mammal. The method may further comprise raising a portion of the mammal to enhance drainage of the vein. The method may also further comprise changing the relative position of a portion of the mammal to facilitate migration of fluid injected into the infusion lumen.
In another embodiment, a method of treating a body lumen is provided. The method comprises providing a catheter with an infusion lumen having a plurality of elution holes contiguous with the infusion lumen, the catheter having a first configuration adapted to resist flow through at least one elution hole and a second configuration adapted to allow flow through at least one elution hole where the catheter is adapted to resist flow in the first configuration, inserting the catheter into a patient, providing a pressurized fluid to the infusion lumen of the catheter and changing the catheter from the first configuration to the second configuration.
Referring now to
An inflatable balloon 20 is located at or near the distal end 14b of inner tube 14 and a fluid valve 22 is coupled to the proximal end 14a of the inner tube 14. The balloon 20 is inflated by injecting fluid (e.g. saline) through the valve 22 and is held in an inflated condition by closing the valve 22.
As seen best in
The proximal end 16a of the outer tube 16 is provided with a trifurcated fitting 28 including a Touhy-Borst type connector 28a, a female Luer 28b with check valve (not shown) and a Luer 28c housing a seal connector (not shown).
The proximal end 14a of the inner tube 14 extends through the Touhy-Borst connector 28a which provides a fluid seal between the inner tube 14 and the outer tube 16 and which selectively locks the inner tube 14 in position relative to the outer tube 16.
The female Luer 28b with check valve permits one-way fluid access into the fluid reservoir 16c′ of the outer tube 16.
A pullwire 30 is coupled to the plunger 26 and extends through the luer 28c of the trifurcated fitting 28 which maintains a fluid seal between the pullwire 30 and the outer tube 16. The proximal end 30a of the pullwire 30 is provided with a handle 32. According to the presently preferred embodiment, the handle is a striking color (e.g. orange) so that it can be quickly located.
According to the presently preferred embodiment, the distal end 14b of the inner tube 14 is provided with a radiopaque tip 14d and a safety wire (not shown in
Further according to the presently preferred embodiment, the outer tube 16 is transparent and provided with a plurality of movable exterior markers 34a to 34d which are used in conjunction with the indication 26a on the plunger 26 in performing the methods of the invention described in more detail below. The presently preferred markers are elastic O-rings.
According to alternate embodiments of the apparatus, other types of tracking devices may be used at the distal end of the inner tube rather than the radiopaque tip. Examples of such devices include an LED or an illuminated fiber optic which is visible through the skin, or a magnet which can be detected with an electromagnetic sensor.
In one embodiment, the apparatus 10 comprises a first syringe 21 having a volume of about 1 mL to about 10 mL for inflating the balloon, and a second syringe 41 having a volume of about 5 mL to about 25 mL for injecting sclerosing agent. In one embodiment, the apparatus comprises a first syringe 21 having a volume of about 2 mL to about 5 mL and a second syringe 41 having a volume of about 10 mL to about 50 mL. In one embodiment, the apparatus 10 is intended for use with and thus also preferably includes two syringes, an about 3 cc to about 5 cc syringe 21 for inflating the balloon and an about 10 cc to about 20 cc syringe 41 for injecting sclerosing agent.
In one embodiment of the invention, although it is not necessary to perform the procedure in an operating room, it is considered prudent for the initial examination to be performed in an out-patient suite in a hospital or in an operating room in the event that any unforeseen events occur that may require surgical intervention.
In one embodiment, the patient is first examined under ultrasound, palpation, fluoroscopy or other means for venous valve insufficiency and varicose veins. If the physician determines that the patient is a candidate for closure of the saphenous vein as a means of eliminating the varicosities, the patient will be admitted for the procedure.
In one preferred embodiment, a photograph of the patient's leg is taken both before and after the procedure so that the results of the procedure can be readily ascertained.
The patient is preferably sedated with a mild sedative and/or pain medication such as Percocet, or the like, one hour prior to the procedure. An intravenous line may be inserted in the patient's arm and vital signs monitored throughout the procedure.
In one embodiment, while the patient is standing, the saphenofemoral junction is located using Doppler or other ultrasonic techniques and the skin marked over this junction with a washable marker. Similarly, the saphenous vein and its major tributary junctions is traced using ultrasound and its path marked on the surface of the skin with a marker.
If varicosities are present above the knee only, then the length of the saphenous vein from the knee to the groin will be treated either through a cut down to the saphenous vein or by a percutaneous stick into the saphenous vein (or both) using a catheter sheath introducer (“CSI”). If the disease is prevalent below the knee, then a similar incision or percutaneous stick will be made in the saphenous vein at the level of the ankle and the vein sclerosed from the ankle to the knee. If the disease is prevalent in both the upper and lower leg, then an incision or percutaneous stick will be made in the saphenous vein at the level of the ankle and the vein sclerosed from the ankle to the groin and the entire vein sclerosed.
The patient lies down with his/her leg elevated 30 to 45 degrees to allow blood to drain from the leg. The patient's leg is scrubbed with a standard surgical preparation medium, such as betadine, and the site prepared for an aseptic procedure. Non-iodine sterilization solutions may be used for patients with iodine allergies. Lidocaine or other local anesthetic is injected into the area around the vein with a small needle. A local anesthetic with epinephrine may be used to provide hemostatic control at the entry or insertion site.
In one embodiment, the apparatus 10 is examined prior to use to determine that it is functioning properly. This should include sliding the plunger in and out through the outer tube and dilating the balloon with about 3 cc of sterile saline to check for leakage.
The following procedure assumes that the patient's skin has been previously marked with the entry site, the occlusion site and important sites (e.g. tributaries) along the vessel. It also assumes that the catheter device can be laid down on the patient's leg while maintaining sterility.
With the inner tube 14 and the intermediate tube 18 drawn into the outer tube 16 as shown in
The inner tube 14 is locked in position by tightening the Touhy-Borst valve 28a. Locking the Touhy-Borst valve assures that when the apparatus is inserted into the leg, the balloon will inflate at the desired occlusion site. It also assures that the balloon will not migrate backwards when the sclerosing agent is dispensed.
Starting with the distal end 18b of the intermediate tube 18 abutting the balloon 20, the pullwire 30 is pulled such that the intermediate tube 18 retracts proximally until the fluid outlet 24 is located at the next marking on the patient's leg (e.g. a tributary site). With the apparatus in this position, the closest marker (o-ring) 34d is moved over the tube 16 until it is aligned with the indicia 26a on the plunger 26. The pullwire 30 is pulled again and this step is repeated for each of the marks on the patient's leg, using the O-rings 34c, 34b, 34a to mark the corresponding location of the plunger 26. It will be appreciated that the number of markers shown in the figures is arbitrary and more or fewer markers may be provided.
After all of the desired markers 34a-34d have been placed along the tube 16, the intermediate tube 18 is pulled distally until its distal end 18b abuts the balloon 20 as shown in
As mentioned above, two syringes are used to operate the apparatus, an about 3 cc to about 5 cc syringe 21 to expand the balloon and an about 10 cc to about 20 cc syringe 41 to dispense the sclerosing agent. The smaller syringe is filled with sterile saline and attached to the fluid valve 22 (a Luer with a stop cock). The larger syringe is filled with sclerosing agent and attached to the female Luer 28b. While holding the intermediate tube 18 in an upward direction, about 10 cc of the sclerosing agent is injected through the check valve 28b into the reservoir 16c′ of the tube 16, through the plunger 26, and up through the tube 18 such that a few drops of fluid emerge from the fluid outlets 24 on the distal end of the tube 18. The physician should ensure that the tubes 16, 18 are purged of air bubbles. If necessary, the larger syringe is reloaded with additional sclerosing agent before proceeding.
The inner tube 14 and the intermediate tube 18 are then inserted into a percutaneous stick 40 in the saphenous vein 42 as shown in
With the apparatus in position as shown in
The balloon is preferably inflated slowly with sterile saline or radiopaque media until it totally occludes the vessel. Ultrasound, fluoroscopy, palpation, tugging, etc. can be used to ensure that the balloon is adequately inflated. Once the balloon is inflated, the stopcock 22 is closed by rotating the stopcock 90°. Doppler ultrasound can also be used to check the absence of blood flow at the occlusion site.
The infusion procedure is begun by pulling the pullwire 30 back until the O-ring on the plunger 26 lines up with the first O-ring marker previously located on the tube 16. Pulling on the pullwire causes the plunger 26 to be moved toward the proximal end of the tube 16, which in turn forces the sclerosing agent out of the fluid outlets 24 in the distal end of the tube 18 which is also moved away from the balloon 20 as shown in
Injection of this bolus of sclerosing agent may be directed and facilitated with a fork-like device (not shown) that compresses the outside of the leg on either side of the fluid outlets 24. A roller may also be used to force the sclerosing agent up the tributary. This process is repeated for other large tributaries. In one embodiment, a total of about 5 cc to about 100 cc of sclerosing agent is used during the procedure. In one embodiment, a total of about 10 cc to 75 cc of sclerosing agent is used. In one embodiment, preferably no more than about 20 cc of 0.5% sclerosing agent should be used in this procedure.
When the tube 18 is fully withdrawn, the balloon 20 is deflated by aspiration and the tube 14 is removed from the vein. The entry site may be sutured before dressing. However, according to the presently preferred embodiment, the size of the introducer is only 6-French which may produce a sufficiently small wound so as not to require suturing. However, the leg is preferably immediately wrapped in a gauze-type dressing (e.g., KERLIX® available from Kendall Co., Walpole, Mass.). A length of foam rubber padding is preferably placed over the gauze and over the saphenous vein that was sclerosed. An elastic bandage (e.g., COACH® or ACE®) is preferably placed over the foam rubber to keep it in place. An additional elastic bandage may be placed over the first elastic bandage to ensure that the vein remains compressed and that blood does not flow back into the treated veins.
The patient should be advised to rest with his/her leg elevated for approximately 30 minutes. The patient can then walk to the car, elevate the leg in the car and then keep the leg elevated in bed overnight. Occasional flexure of the foot, ankle and leg should be encouraged. It is preferred that the patient be re-examined the following day. The dressings should then be replaced and the patient instructed on how to self apply new dressings and bandages. The dressings, foam pads and bandages may be kept in place for five to seven days. After five to seven days, the patient should be re-examined and, if indicated, the dressings and foam removed. The compression bandage should be worn for an additional week.
The patient should be asked to return for follow-up at one month and three months if indicated. The patient may also be asked to return at one year to evaluate the long-term effectiveness of the procedure.
The benefits of the methods and apparatus of the invention include:
Sclerosing agents are painless in the vascular system as compared to laser or RF ablation that can be extremely painful.
The occlusion balloon prevents the sclerosing agent from entering the deep venous system via the saphenofemoral or saphenopopliteal junctions.
The catheter is 6-Fr in diameter and is easily maneuvered through the vein.
Only one injection of anesthesia is required at the puncture site, resulting in less pain and toxicity to the patient.
Venous access via a small cut down or by use of a catheter sheath introducer produces a very minimal scar, resulting in a better cosmetic impact.
The recovery time is faster with fewer cosmetic complications as compared to stripping.
Tributaries can be treated as well as the main veins resulting in a better cosmetic impact.
Veins below the knee can be treated.
The total procedural time is greatly reduced.
The apparatus is less expensive than laser and RF apparatus.
The procedure is performed in an outpatient setting.
The apparatus automatically assures that the correct amount of sclerosing agent is evenly distributed without requiring the practitioner to carefully monitor the duration of treatment.
FIGS. 5 to 12 illustrate additional vessel flow blocking or occlusion methods and devices according to the present invention.
In one embodiment, the umbrella 212 is a structure made of elastic or superelastic wires or struts which are biased to be in an “open,” larger-diameter configuration when there is no external restraint on them, e.g. when released from the catheter. These struts or wires are covered with a membrane or very fine mesh which effectively occludes the flow of blood. Alternatively, the struts can be biased to the closed position, and the structure may be expanded by applying a force to compress the structure axially (by means of two push-pull wires) so as to expand it. (See the previously incorporated co-pending application Ser. No. 10/328,085).
In one embodiment, the umbrella 312 includes a tubular inflatable cuff 312a at the distal end of a funnel-shaped membrane 312b. When inflated, the tubular cuff assumes a toroidal shape which expands the membrane to the form of a funnel, contacts the inside wall of the blood vessel and occludes fluid flow. U.S. Pat. No. 5,908,435 describes a catheter device with an inflatable cuff, which when inflated forms a similar funnel-like structure.
The umbrella 412 includes an expandable loop of wire 412a coupled to an impervious membrane or film bag 412b. Once extended, the loop and bag expand to fill the lumen of the blood vessel, blocking the flow of fluid.
In one embodiment, it is possible to occlude the superficial saphenous vein solely by the application of external compression, either by hand or by means of a mechanical assistive device. Examples of compression devices include: inflatable cuffs, inflatable cuffs with means for localizing compression (for example, a rubber bougie or ball), and a mechanical clamping device with a padded “foot.”
FIGS. 13 to 18 illustrate methods and apparatus for locating an occlusion device in a blood vessel. Turning now to
According to the methods of the invention, an additional bolus of treating agent is optionally dispensed when the treating catheter passes a tributary blood vessel. FIGS. 19 to 24 illustrate methods for locating tributary blood vessels which include pre-marking the patient's skin.
Another (unillustrated) method of utilizing the pre-markings on the patient's leg is to use a catheter with a light source at its treating end such as the light source shown in
The invention also contemplates methods of locating the treating end of a catheter at tributaries without pre-marking via different types of imaging such as ultrasound such as described above with reference to
FIGS. 26 to 32 illustrate various catheter devices according to the invention.
Turning now to
According to the invention, the weeping catheters described above with reference to FIGS. 30 to 34 may be provided with different perforation configurations. The diameters of the perforations may be constant or variable. The spacing of the perforations may be constant or variable. Perforations may be provided in groups which are evenly spaced or variably spaced. The number of perforations per group may be constant or variable. These different configurations are chosen so as to provide either equal or biased infusion along the treating length of the weeping catheter.
FIGS. 35 to 37 illustrate a portion of a weeping catheter 1200 which can be considered to be a combination of the catheters 1000 and 1100. In this embodiment, the inflation catheter (or lumen) 1206 is not coaxial with the weeping catheter 1200 and the infusion space (or lumen) 1202 is not annular as in the catheter 1100. However, the distal end 1214 of the inflation catheter is provided with an inflatable balloon 1207 which is substantially similar to the arrangement shown in
In one embodiment, each access port 1306, 1308, 1310 is in fluid communication with a lumen running generally along the length of the catheter body. In some embodiments, a lumen may be in fluid communication with multiple access ports. In one embodiment, at least one access port 1306 is in fluid communication with an infusion lumen allow infusion of a treatment agent into the catheter 1300 and out through the holes 1302 of the catheter body 1312. In one embodiment, one access port 1310 and lumen 1320 is provided to allow manipulation of the blood vessel occluder 1316 from the proximal end 1304 of the catheter 1300. The inflation lumen 1320 may be integral with the outer catheter wall 1322 or be defined within a separate tubular wall (not shown) within the infusion lumen 1318.
In one embodiment, the catheter 1300 is configured so that the fluid elution from the holes 1302 generally occurs in a particular predetermined pattern when the fluid is injected through the catheter 1300 at a specific viscosity and pressure or pressure range. In one embodiment of the invention, the pattern of fluid elution is determined by at least one of several factors, including but not limited to: 1) the hydraulic diameter D′ of the infusion lumen of the catheter; 2) the hydraulic diameter d′ of each elution hole; 3) the spacing s' between each elution hole; 4) the overall treatment length L′ of the catheter; 5) the viscosity of the agent used for treatment; and 6) the compressibility of the treatment agent. The term “hydraulic diameter”, as used herein, shall be given its ordinary meaning and shall also include the equivalent diameter of a structure when estimating pressure loss or head loss in non-circular lumena using data made for circular lumena. The term “treatment length” as used herein shall mean the portion of the catheter generally from about the most proximal elution hole 1324 to about the most distal elution hole 1326.
In one embodiment, the fluid distribution from the catheter 1300 is generally even along the treatment length of the catheter 1300. In another embodiment, the pattern of fluid distribution from the catheter 1300 provides for increased elution of agent at the distal end 1314 of the treatment length. The change in elution along the treatment length may be a gradual ramp or stepped. In another embodiment, the fluid distribution pattern provides greater elution at the proximal end 1304 of the treatment length. In another embodiment, the catheter 1300 provides a customized distribution pattern adapted to provide increased flow at one or more locations along the treatment length which is adapted to correspond to the location of the venous tributaries when the occluder has been positioned as described herein. In another embodiment, the catheter 1300 provides a customized distribution pattern adapted to provide increased flow at the venous tributaries and about the saphenofemoral junction. One skilled in the art will understand that the catheter may be configured for any of a variety of elution or distribution patterns.
The diameter D′ of the infusion lumen 1318 of the catheter 1300 generally ranges from about 0.03″ to about 0.20″. In certain embodiments, the diameter d′ ranges from about 0.05″ to about 0.09″. In one embodiment, the diameter d′ is about 0.072″.
The overall treatment length L′ of the catheter generally ranges from about 10 cm to about 175 cm. In certain embodiments, the treatment length L′ is within the range of from about 20 cm to about 100 cm. In another embodiment, the treatment length L′ is within the range of from about 20 cm to about 44 cm.
The viscosity at body temperature of the treatment agent is generally within the range of from about 1.00E-04 (lb*s/in{circumflex over ( )}2) to about 1.00E-08 (lb*s/in{circumflex over ( )}2). In certain embodiments, the viscosity of the treatment agent is within the range of from about 1.00E-06 (lb*s/in{circumflex over ( )}2) to about 1.00E-08 (lb*s/in{circumflex over ( )}2). In one embodiment, the viscosity is about 1.74E-07 (lb*s/in{circumflex over ( )}2). Viscosities outside of the foregoing ranges may also be used, taking into account the pore sizes, infusion lumen length and diameter, as long as the desired delivery performance (e.g. delivery rate) is achieved. Sclerosing agents used for treating veins are generally incompressible, but compressible agents may also be used.
In one embodiment, the spacing s' between the elution holes 1302 ranges from about 0.01 cm to about 10 cm. The spacing s' between the elution holes 1302 may range from about 0.50 cm to about 5 cm. In other embodiments, the spacing s' between the elution holes 1302 is about 0.50 cm to about 3 cm. In another embodiment, the spacing s' between the elution holes 1302 is about 0.50 cm to about 2 cm.
The diameter d′ of the elution holes 1032 may be selected for the desired elution pattern by considering the catheter and sclerosing agent characteristics described previously and the pressure drop-off along the catheter length. In one embodiment of the invention, the elution hole diameter is about 0.001″ to about 0.015″. In another embodiment, the elution hole diameter is about 0.002″ to about 0.010″. In one embodiment, based upon a 6-French catheter with a length greater than 40 cm, elution hole spacing between 1 cm and 2 cm and sclerosing agent characteristics described previously, an elution hole diameter of about 0.004″ or less is capable of providing a generally uniform fluid elution along the length of the infusion catheter 1300. Other elution hole diameters may also be used, depending on the desired elution pattern for the infusion catheter and the catheter and sclerosing agent characteristics used.
In one embodiment of the invention, the diameters d′ of the elution holes 1302 each have an effective hydraulic diameter less than the fluid distribution lumen D′ that connects the elution holes 1302. In a further embodiment, the total fluid resistance of the plurality of elution holes 1302 is generally equal or greater than fluid resistance of the infusion lumen 1318 or lumena of the catheter. In still a further embodiment of the invention, the total fluid resistance of the plurality of elution holes 1302 is substantially greater than the fluid resistance of the catheter infusion lumen 1318. By providing elution holes 1032 with a total fluid resistance substantially greater than the infusion lumen 1318, uniform elution along the catheter 1300 may be achieved. The total fluid resistance of the infusion lumen should generally be less than about 80 percent of the total fluid resistance of the elution holes, and in certain devices less than about 50 percent of the total fluid resistance of the elution holes. The hydraulic diameters of the elution holes 1302, however, are not limited to consideration of the factors described above.
The wall thickness of the infusion catheter 1300 may also contribute to the total fluid resistance of the plurality of elution holes 1032. The wall thickness essentially corresponds to the length of a capillary tube, creating resistance to flow which may at least theoretically be determined by well known relationships such as Poiseuille's law. For example, a 6-French catheter made of Versamid® polyamide resin may have a wall thickness within the range of about 0.006″ to 0.015″. Where the elution holes have a hydraulic diameter of about 0.004″ or less, the wall thickness, which defines the length of the elution holes 1302, may contribute to the fluid resistance of the elution hole 1302. In one embodiment of the invention, the catheter has a wall thickness of about 0.003″ to about 0.100″. In another embodiment, the catheter has a wall thickness of about 0.004″ to about 0.060″. In another embodiment, the catheter has a wall thickness of about 0.005″ to about 0.030″. In still another embodiment, the catheter has a wall thickness of about 0.004″ to about 0.020″.
The elution rate at a given segment of the catheter is affected by spacing s' and hole diameter d″ of elution holes 1302, the distance of the segment from the proximal end of the catheter, as well as the spacing s' and diameter d′ of the other catheter segments. One skilled in the art will understand that these characteristics, and other characteristics described previously, can be altered to achieve a different elution pattern.
A porous portion 1332 may comprise a full circumference of catheter, as shown in
In one embodiment of the invention, a system for controlling or altering the flow of medicament at an elution hole, a series of elution holes, or a porous region is provided. Multiple elution control systems may be used in the same catheter to provide control over multiple portions of the catheter. A control system may also be capable of protecting the elution hole from clogging with blood components by exposing the elution hole only during periods of desired elution and protecting the elution holes at other times. Several embodiments of the control system are described below.
Medicament from the infusion lumen 1346 is capable of flowing through the inner holes 1344a-1344d, intersecting the side lumen 1340, and passing through the outer holes 1348a-1348f to exit from the catheter 1342 when the occluder 1350 is in a first, open position or has been withdrawn from the catheter. The inner holes 1344a-1344d and outer holes 1340a-1340f need not be aligned, and the number of inner 1344 and outer holes 1348 need not be equal. Inner hole 1344a and outer hole 1348a depict aligned holes whiles inner hole 1344d and 1348f depict non-aligned holes.
Any inner hole 1344 and outer hole 1348 capable of providing flow out of the catheter 1342 defines an elution hole or pathway. Any inner hole 1344 or outer hole 1348 may define more than one elution hole or pathway. For example, inner hole 1344c is capable of flow to outer holes 1348c-1348e. The cross-sectional areas of the inner holes and outer holes need not be equal and may vary within the same hole. In one embodiment, an inner hole 1344d has a greater diameter than outer hole 1348f. In one embodiment, a greater number of outer holes may be desired to create a more uniform elution pattern. In one embodiment, increased elution from outer holes that are closer to the inner holes can be reduced by decreasing the alignment between the inner holes and the outer holes to increase the tortuosity of the flow path and provide a more even distribution pattern from the outer holes.
The cross sectional shape of the elution holes can be circular, oval, square, triangular or any polygonal or closed shape. The cross sectional shape of the elution holes need not be uniform throughout the longitudinal length of the elution hole. In certain embodiments, the inner holes have a circular diameter of about 0.002″ and the outer holes have a rectangular shape, with a length of about 0.022″ as measured along the longitudinal axis of the catheter, and a width of about 0.007″. In one embodiment, a rectangular outer hole configuration where the width of the hole is about equal to the diameter of the occluder is used to provide better flow around some occluder configurations.
In one embodiment, the movable occluder 1350 is located generally along the length of the side lumen 1340, such as coaxially within the side lumen 1340. In one embodiment, the movable occluder 1350 comprises at least one narrow connector portion 1352 with a narrow diameter and at least one blocking portion 1354 which, in the illustrated embodiment, comprises an enlarged diameter or width that is capable of forming a seal with the side lumen. Movable occluders with a uniform diameter may also be used, but such occluders may exhibit increased resistance to sliding compared to occluders with variable diameters.
In sealing with the side lumen 1340, the enlarged portion 1354 may block an inner hole, an outer hole or both.
In one embodiment, the side lumen has an internal diameter of about 0.025″ and the occluder comprises a valving wire with narrow portions having a primary diameter of 0.015″ and at least one enlarged portion with a diameter of about 0.022″ to about 0.024″ by about 0.200″ length. When the enlarged portion of the occluder is positioned next to an inner hole or outer hole, the elution hole or pathway defined by the inner hole and outer hole is “closed” and flow from the infusion lumen out of the catheter is blocked or resisted. When the enlarged portion of the valving wire is positioned away from a pair of inner and outer holes, the pair of holes is “open” and medicament is able to flow through the holes and out of the catheter.
In another embodiment, the occluder comprises a movable ribbon having narrow portions and wider portions that is capable of reversibly occluding the elution holes. Alternatively, the occluder may comprise a rotatable element, such as an elongate tubular body having side wall apertures aligned to permit or block fluid communication between the central lumen 1346 and one or more ports on the exterior wall of the catheter.
In one embodiment, the occluder is configured to generally open all of the elution holes or porous segment simultaneously. This allows the user to quickly initiate the fluid elution along the entire length of catheter, so that the dilution of the medicament by flowing blood is reduced. The risk of plugging or blocking the elution holes with clotted blood components may also be reduced by quickly opening generally all the elution holes.
In certain embodiments of the invention, illustrated in
In one embodiment, the first position of the occluder 1356, depicted in
In certain embodiments, the elution holes can be opened sequentially along the length of the delivery zone to provide and then closed, a moving elution zone without repositioning the catheter, or to allow a single catheter length to be used for treating patients requiring different delivery zone lengths. One example of the latter configuration comprises a catheter having a 44 cm delivery zone that is only partially inserted into a patient's leg because only a 24 cm delivery zone was required. The catheter will not leak sclerosant from the proximal 20 cm that lies external to the patient where the occluder is configured and positioned to only open the elution holes in the distal 24 cm of the catheter. In another embodiment, the occluder is configured so that the elution holes are opened in groups rather than individually, by either arranging the elution holes circumferentially in the same longitudinal region of the catheter, or by provide the enlarged portions of the occluder with sufficient length or particular spacing to simultaneously block multiple holes.
In one embodiment, an infusion catheter with an occluder capable of sequentially opening the elution holes may also be advantageous when infusing foam-based medicaments, including but not limited to sodium tetradecyl sulfate. The inventors have found that when elution holes with cross-section areas comprising a significant fraction of the infusion lumen cross-sectional area are used, it is common for liquid and foam-based medicaments to preferentially elute from the first hole that the foam encounters as it enters the catheter. In simple catheter constructions, this is typically the most proximal elution hole. Foam is typically disposed to elution in this manner because of its compressibility. During elution, the pressure of injection causes the foam to be compressed until it encounters an opening in the catheter, where it expands into the lower-pressure environment outside the catheter. To compensate for the increased elution of medicament at the proximal end of the catheter treatment zone, a catheter with a sequentially opening elution hole controller may be used. In one embodiment, to provide infusion of medicament along the entire length of the treatment zone, the most distal elution holes or elution zones are opened first, so that the medicament will elute from these distal areas. The adjacent proximal elution holes and/or elution zones are then sequentially opened to allow elution in a more proximal fashion. By using a sequentially opening catheter, a medicament that elutes primarily from the first-encountered elution hole may be dispensed evenly across the entire length of the catheter treatment zone. In one embodiment, elution control may be accomplished by proximally retracting a valving wire, but other control structures can also be used.
It may be advantageous for the catheter user to be able to elute a bolus of medicament at a specific location in the body, in addition to the even elution across the treatment zone of the catheter. Bolus treatment may be accomplished with a catheter comprising two elution systems: a) an “even-elution” system as previously described using a series of elution holes or pores which simultaneously or sequentially elute over a prescribed portion of the infusion catheter, and b) one or a series of sequentially-openable larger openings that will elute medicament (either foam or liquid) at a bolus delivery zone. Before, during or after performing an even elution, the operator may use the second system of larger holes to deliver a single or multiple boluses to specific areas in the blood vessel.
In one embodiment, shows in
In one example, an infusion catheter comprising a side lumen and an array of ten elution holes, with one hole per centimeter over a nine centimeter length, is provided. The side lumen contains a single square wire of at least about 9 cm length. In one embodiment, a smaller-diameter pull wire is engaged the proximal end of the square wire, to allow manipulation of the square wire from the proximal end of the catheter. In an alternate embodiment, to simplify manufacture of the square wire occluder, a square wire with a length at least sufficient to extend from through the proximal end of the catheter to the distal end of the catheter treatment segment is used as an occluder. In one embodiment, short segments of the wire may have cross-sections closer to or matching that of the side lumen to limit the extent of lengthwise leakage, without significantly increasing the net sliding friction of moving or withdrawing the wire from the catheter.
In another embodiment shown in
The outside diameter of the flow regulating tube 1450 is moveable from a first, reduced diameter to a second enlarged diameter upon introduction of inflation media into the central lumen 1452. The outside diameter of the tube 1450 in the first, relaxed configuration is less than the inside diameter of the lumen within which it resides, such as side lumen 1448. In this configuration, a medicament or other agent in the infusion lumen 1456 is capable of flowing past or around the hollow tube 1450 to exit out of the elution hole 1454. See
The flow regulating tube 1450 thus provides a movable wall which may be advanced between a first orientation in which flow is permitted to occur and a second orientation in which flow is inhibited. Introduction of intermediate pressures into the central lumen 1452 may be utilized to regulate flow at intermediate flow rates, or permit flow only to occur when the driving pressure within the infusion lumen 1456 exceeds a predetermined threshold.
Although the flow regulating tube 1450 is described as located within the side lumen 1448, valves or flow regulators which are responsive to changes in pressure may be incorporated into the catheter of the present invention in any of a variety of ways. For example, the inflatable tube 1450 may be positioned within the inflation lumen 1456, and the side lumen 1448 may be eliminated or utilized for another purpose. The inflatable tube 1450 may be configured to have an axial length less than the length of the infusion zone, such that, for example, it occludes only a relatively proximal portion of the catheter body. In one implementation, the flow regulating tube 1450 has an axial length of no greater than 2 or 3 or 4 times the inflated diameter, such that it operates as an inflatable valve positioned in-between the proximal most elution hole and the source of infusion media. In general, however, it appears desirable for the axial length of the flow regulating tube 1450 to be at least as long as the infusion zone, such that in the inflated configuration, the flow regulating tube 1450 physically occludes each elution hole 1454.
The escape of material from the infusion lumen 1456 through each elution hole 1454 may be accomplished by providing an inflatable tube 1450 at any point between that elution hole 1454 and the source of infusion media. However, it also appears desirable to block each elution hole 1454 to prevent blood or other body fluid from entering the catheter in a retrograde flow direction, prior to the time that the sclerosant or other infusion media is infused from the catheter into the patient. Thus, in accordance with the present invention, there is provided a method and related device for introducing a catheter into a patient, the catheter having a plurality of elution holes 1454, and preventing the introduction of body fluid into the catheter through the elution holes. The introduction of body fluid into the catheter is inhibited by the positioning of a movable wall across the elution hole. The moveable wall is moveable between a first position in which it occludes the elution hole 1454, and a second position in which the infusion lumen 1456 is in communication with the exterior of the catheter through the elution hole 1454. In the illustrated embodiment, the moveable wall is the surface of an inflatable tube, although other structures for moving a wall between a first position and a second position may also be utilized.
Although the present embodiment has been described primarily in terms of a hollow flow regulating tube 1450 having a reduced outside diameter in its relaxed configuration, the device may alternatively be constructed such that the hollow flow regulating tube 1450 resides in an enlarged cross sectional diameter in it relaxed configuration. This configuration would provide a “normally closed” valve system, in which the outside diameter of the flow regulating tube 1450 would normally occlude the elution hole 1454. In this construction, drawing a negative pressure on the central lumen 1452 could be utilized to reduce the cross sectional area of the flow regulating tube 1450, thereby placing the elution hole 1454 into communication with the infusion lumen 1456.
The tube 1450 may comprise any of a variety of materials that may be expanded under pressure, such as latex, silicone rubber, natural rubber, neoprene and other chloroprene variants, polyurethane, ethylene-propylene, polyvinyl chloride, polyamide, polyamide elastomer, copolymer of ethylene and vinyl acetate, polyethylene, polyimide, polyethylene terephthalate, fluorocarbon resin, polyisobutylenes and other thermoset elastomers, polyisoprene, or any of a variety of materials known in the art that is capable of radial expansion when fluid in the hollow portion 1452 of the tube 1450 is pressurized.
In one embodiment, depicted in
The ratio of the first, reduced diameter of the flow regulating tube 1450 to the inside diameter of the lumen within which it resides can be varied widely, depending upon the desired performance characteristics, taking into account the viscosity and desired flow rate of the infused media. In general, the deflated diameter of the tube 1450 will be no greater than about 75% of the inside diameter of the side lumen 1448. In certain constructions, the deflated outside diameter of the flow regulating tube will be no more than about 65%, and, in certain implementations, no greater than about 60% of the inside diameter of the lumen within which it is contained.
In certain constructions, the hollow elastomeric tube 1450 has a deflated outside diameter ranging from about 0.008″ to about 0.100″. In certain embodiments, the tube 1450 has a deflated outside diameter ranging from about 0.010″ to about 0.050″. The elastomeric tube has a deflated internal diameter generally within the range of from about 0.003″ to about 0.080″. In a preferred embodiment, the elastomeric tube has an outer diameter of about 0.015″ and an inner diameter of about 0.006″, for use in a lumen having an inside diameter of about 0.025″.
The inflation pressure sufficient to occlude the elution holes may range from about 10 pounds per square inch (psi) to about 1000 psi. In certain embodiments, the occlusion pressure is about 50 psi to about 500 psi. In another embodiment, the occlusion pressure is about 100 psi to about 600 psi. In one embodiment, where the occluder comprises an elastomeric tube with an outer diameter of about 0.015″ and an inner diameter of about 0.006″ in a 0.025″ side lumen, the tube has an occlusion pressure at about 100 psi to about 200 psi.
The tube diameter, wall thickness, wall compliance, and other tube characteristics may be varied along the length of the bladder tube. One skilled in the art may alter these characteristics to provide different occlusion characteristics across a pressure range. In one example, a bladder tube may be designed to sequentially deflate from distal to proximal over a pressure range from 200 psi to 100 psi. Distal to proximal deflation may be accomplished, for example, by providing a first wall thickness for the elastomeric tube 1450 in the proximal end and a second, greater wall thickness for the elastomeric tube 1450 near the distal end. Wall thickness may be graduated continuously from the proximal end to the distal end. Alternatively, deflation may be accomplished initially at the proximal end by providing the greater wall thickness at the proximal end. As will be apparent to those of skill in the art in view of the disclosure herein, the inflation characteristics of the foregoing constructions will be the reverse of the deflation characteristics, such that portions of the flow regulating tube with a relatively lesser wall thickness will inflate at a lower pressure than portions of the flow regulating tube with a greater wall thickness. The sequential expansion during inflation may occur smoothly across the length of the flow regulating tube, or in a segmented fashion. In another example, the bladder tube may comprise dimples in the bladder tube that evert and occlude elution holes at a particular pressure threshold.
In one embodiment of the invention utilizing an inflatable flow regulator form of occluder, the occluder comprises an inflatable tube in a catheter with outer hole diameters of about 150 microns or greater and inner holes diameters of about 200 microns or less. In another embodiment, the catheter comprises outer hole diameters of about 400 microns or less and inner hole diameters of about 5 thousandths of an inch (200 microns) or more. In one embodiment, the outer holes have diameters of about 200 microns or more and inner holes of about 20 microns to about 250 microns. In another embodiment, the outer holes have diameters of about 20 microns to about 250 microns and the inner holes have diameters of about 200 microns or more. In one embodiment, at least either the outer holes or inner holes have a diameter of about 8 microns to about 175 microns. In a preferred embodiment, the catheter comprises outer holes with diameters of about 300 microns or greater and inner holes with diameters of about 50 microns to about 175 microns. The inner holes may have the same, a smaller, or a larger diameter than the corresponding outer hole.
The elastomeric tube may be pressurized with a pressure controller comprising variable volume container such as a syringe. The syringe may have a capacity of about 0.25 cc to about 25 cc, and may be is attachable such as by a Luer connector to the proximal end of the inflatable tube. In certain embodiments, the syringe has a capacity of about 1 cc to about 5 cc. In a preferred embodiment, the syringe has a capacity of about 1 cc to about 2 cc.
The plunger of the syringe may be controlled directly by the operator or through a lever or knob with detent. In another embodiment, the pressure controller comprises an electronically controlled pump and pressure release valve. One skilled in the art will understand that any of a variety of pressure controllers may be used. In one embodiment, the syringe or catheter further comprises a stopcock for maintaining pressure in the elastomeric tube without further effort by the user. In another embodiment, the plunger or tube controller further comprises a latch for maintaining the position of the plunger. In a preferred embodiment, the tube controller provides a two-position control of the tube where the tube is either inflated or deflated. In another embodiment, the pressure controller is capable of providing multiple degrees of tube pressurization. A controller providing multiple degrees of tube pressurization may be useful to provide variable flow patterns or varying degrees of flow through the elution holes to further control the flow rate of medicament out of the catheter.
In one embodiment of the invention, the hollow elastomeric tube is pressurized with a gaseous medium. In one embodiment, the tube is pressurized with a liquid medium. A liquid medium may be preferred to decrease the risk of an air embolus in the venous system that may travel to the lungs or other sites and block tissue perfusion.
In one embodiment of the invention, the elastomeric or bladder tube comprises silicone or other porous material that is sufficiently permeable so that any trapped gas in the tube can be expelled by inflating the tube with a liquid to at least about 100 psi. Under such a pressure, the gases diffuse out through the permeable tube and/or into the liquid medium. In another embodiment, the bladder tube comprises a material such as neoprene that is generally permeable to gas but not to a liquid, such that when pressurized with a liquid, gases are allowed to escape through the pores of the material but liquid is retained. In another embodiment, any trapped gas in the tube is expelled by inflating the tube with a liquid to at least about 40 psi. In another embodiment, any trapped gas in the tube is expelled by inflating the tube with a liquid to at least about 200 psi.
In one embodiment, the catheter and/or syringe further comprises an indicator of elution hole occlusion by the bladder tube, or pressure in the bladder tube. In one embodiment, the indicator comprises markings on the pressure controller, such as the syringe or syringe plunger. In one embodiment, a pressure indicator independent of the pressure controller or pressure actuator is provided in the catheter. An independent pressure indicator may be advantageous over other mechanisms of pressure status in situations where leakage or failure of the bladder tube has occurred. For example, in a catheter where the bladder tube has ruptured, a plunger position marker on a syringe will indicate that a leaking bladder tube is fully pressurized, while an independent pressure indicator may accurately show that the bladder tube is unpressurized even though the plunger is fully depressed. In one embodiment, a poppet-type pressure indicator is attached to the catheter to indicate pressurization of the bladder tube. In another embodiment, a MEMS type pressure sensor is provided on the catheter to indicate the pressure status of the bladder tube. One skilled in the art will understand that any of a variety of pressure detection mechanisms may be used for a pressure indicator for the bladder tube.
In accordance with another embodiment of the invention, the elution holes of the catheter 1458 comprise a plurality of slits in the outer catheter wall 1462 through which medicament is able to pass.
In one embodiment, the angle a′ of the slit between the external surface of the catheter to the inner surface of the catheter to form the cover 1460 is at a 90 degree angle to the surface of the catheter. In another embodiment, the slit angle a″ may be anywhere from about 1 degree to about 179 degrees to the catheter surface.
One advantage of slit-based elution holes is the higher pressure required to open the slit valves. The higher opening pressure reduces the influence that the infusion pressure may have on the elution or flow pattern along the length of the catheter, due to the pressure drop along the length of the catheter. For example, in a catheter where there is a viscous pressure drop from the most proximal elution hole to the most distal elution hole of 20 psi and the slits open at a pressure of about 80 psi, if the pressure at the most proximal hole is 100 psi, the flow rate out of the most distal elution whole will be approximately {fraction (80/100)}ths or 80% of the flow rate out of the most proximal elution hole, because the pressure at the most distal hole will be about 80 psi. Where the catheter slits are configured to open at 100 psi (and making a simplifying assumption that flow is proportional to pressure once the slit is opened), if the pressure at the most proximal elution slit is 200 psi, the pressure at the most distal slit is 180 psi. The resulting flow from the most distal slit would be about {fraction (180/200)}ths or 90% of that at the most proximal slit. By altering the configuration of the slits, a catheter may be configured to provide an even elution pattern, or any other elution pattern, independent of the location of the slits along the catheter.
In one embodiment of the invention, as shown in
In one embodiment of the invention, shown in
In one embodiment of the invention, shown in
In another embodiment of the invention, comprising a catheter with a slidable control tube overlying the elution holes of the catheter and is slidable in a direction along the longitudinal axis of the catheter. The control tube has an extended position whereby the control tube is positioned over the elution holes to protect the elution holes from clogging and other damage, and a withdrawn position that provides for elution of medicament out of the elution holes. The control tube is also capable of intermediate positioning between the the extended and withdrawn positions. Intermediate positioning between the extended and withdrawn positions may be configured for smooth sliding or segmented sliding. With segmented sliding, slight resistance to movement is created along regular or desired intermediate positions to provide predictable positioning of the control tube. The resistance may be created by spaced protrusions and indentations between the control tube and catheter that are capable of forming a friction fit. The proximal end of the control tube may have a resistance lock capable of reversibly securing the relative position of the control tube and the catheter.
In one embodiment of the invention, the catheter system further comprises a sterilizing filter in the flow path between the medicament source and the elution holes that is capable of filtering particles size as small as about 0.2 microns. A sterilizing filter may be particularly advantageous when the medicament comprises a foam. Techniques for producing foam-based medicaments often require the user to generate the foam at the time of the procedure by mixing the medicament with ambient air, which may contain particulates and biologically active materials. A sterilizing filter may be an integrally formed part of the catheter, or it may be attachable to the catheter, which is then attached to the medicament source for infusion into the catheter.
In one embodiment of the invention, a method for using a longitudinal infusion catheter is provided. The patient is placed on a flat surface and prepped and draped in the usual sterile fashion. The venous anatomy is evaluated and the insertion site is marked and selected. Tributary sites and other sites that may require additional therapy are identified and the distance measured relative to the insertion site or other similar site. Catheter integrity and function is verified by checking balloon inflation and infusion of saline, heparinized saline or other sterile fluid into the infusion lumen of the catheter. In one embodiment, the balloon is pressurized to at least about 100 psi with a syringe to purge the gaseous fluid in the distal balloon. Functionality of the elution hole controller, if provided, is checked. Local or general anesthesia is achieved as needed. Local anesthesia may be achieved with the injection of 1% lidocaine at the insertion site using a syringe with a 20 gauge to 25 gauge needle. An 18 gauge needle on a 5 mL syringe is then inserted into the anesthetized skin while aspirating. When venous blood return is confirmed, the needle is held in place as the syringe is removed. In one embodiment, a “J” wire is inserted through the needle. Resistance is checked during the wire insertion. If resistance is encountered, the needle is repositioned and wire insertion is repeated. If no resistance is encountered, wire position is maintained as the needle is removed over the wire. A vessel dilator and catheter introducer sheath is passed over the wire and optionally secured to the skin or the limb by a strap, suture or other anchoring mechanism known in the art. The wire and vessel dilator are removed from the catheter introducer sheath and replaced with the infusion catheter. In one embodiment, a catheter lock on the introducer secures the position of the catheter relative to the introducer. The limb to be treated may be raised to facilitate drainage of blood out of the vein. The position of the catheter distal tip is verified and the distal balloon is inflated, or alternatively, the distal vein occluder is activated. A 5 mL syringe with isotonic saline is attached to the balloon inflation lumen of the catheter and the plunger is fully depressed. Balloon inflation and/or blood flow across the balloon is evaluated by radiographic or other means. In one embodiment, a bolus of heparin is injected into the catheter through the infusion lumen access port while the elution holes are open to verify and maintain patency of the elution holes. In one embodiment, radio-contrast agent is injected into the blood vessel under radiographic visualization to confirm the vessel anatomy. Radio-opaque interval markers may be positioned about the leg to facilitate localization of any areas of interest visualized by the radio-contrast agent.
The sclerosing agent is prepared as needed and a 20 mL syringe filled with the agent is attached to the infusion lumen access port. A pressure dressing may be applied to the treatment area to enhance vessel wall contact during the infusion of treatment agent. In one embodiment, the infusion catheter is configured for a first elution pattern or location and an amount of agent is dispensed from the syringe and into the vessel. The treated limb may be optionally lowered to a horizontal position to facilitate even distribution of the agent during injection. The position of the limb may also be altered with respect to the level of the heart to facilitate movement of the injected migration to areas requiring enhanced sclerosing effect. In instances where a foam-based sclerosing agent is used, the treated limb may be placed in initially in an elevated position to enhance drainage of venous blood from the limb, then placed below the heart during injection to facilitate migration of the foam-based sclerosant to the saphenofemoral junction to provide increased sclerosing effect. In one embodiment, the catheter is reconfigured for another elution pattern or location and additional agent is injected into the vessel. The reconfiguration of the catheter and dispensing of agent is repeated as needed. In one embodiment, treatment effect is evaluated between injections and additional treatment sites may be identified. The catheter is reconfigured to elute agent at the additional sites and additional treatment agent is injected. In one embodiment, heparin boluses or other anti-coagulation agent are infused through the infusion lumen and elution holes of the catheter between injections of the sclerosing agent or radio-contrast agent to maintain patency of the infusion catheter. The distal balloon of the catheter is deflated and the catheter is withdrawn from the patient. The introducer is removed from the insertion site and hemostasis is achieved by placing one or more non-absorbable sutures to close the insertion site. The insertion site is cleaned with alcohol and dressed. A pressure dressing or wrap is applied around treated limb as needed.
In one embodiment of the invention, a method for using an infusion catheter with an occludable bladder tube is provided. The patient is placed on a flat surface and prepped and draped in the usual sterile fashion. The venous anatomy is evaluated and the insertion site is marked and selected. Tributary sites and other sites that may require additional therapy are identified and the distance measured relative to the insertion site or other similar site. Catheter integrity and function is verified by checking balloon inflation and infusion of saline, heparinized saline or other sterile fluid into the infusion lumen of the catheter. In one embodiment, the balloon is pressurized to at least about 100 psi with a syringe to purge the gaseous fluid in the distal balloon. Integrity of the bladder tube is assessed by inflating the bladder tube and verifying occlusion of the elution holes by the bladder tube. The bladder tube is deflated and reopening of the elution holes is rechecked. Local or general anesthesia is achieved as needed. Local anesthesia may be achieved with the injection of 1% lidocaine at the insertion site using a syringe with a 20 gauge to 25 gauge needle. An 18 gauge needle on a 5 mL syringe is then inserted into the anesthetized skin while aspirating. When venous blood return is confirmed, the needle is held in place as the syringe is removed. In one embodiment, a “J” wire is inserted through the needle. Resistance is checked during the wire insertion. If resistance is encountered, the needle is repositioned and wire insertion is repeated. If no resistance is encountered, wire position is maintained as the needle is removed over the wire. A vessel dilator and catheter introducer sheath is passed over the wire and optionally secured to the skin or the limb by a strap, suture or other anchoring mechanism known in the art. The bladder tube is reinflated to occlude the elution holes. The wire and vessel dilator are removed from the catheter introducer sheath and replaced with the infusion catheter. In one embodiment, a catheter lock on the introducer secures the position of the catheter relative to the introducer. The position of the catheter distal tip is verified and the distal balloon is inflated. A 5 mL syringe with isotonic saline is attached to the balloon inflation lumen of the catheter and the plunger is fully depressed. Balloon inflation and/or blood flow across the balloon is evaluated by radiographic or other means. In one embodiment, a bolus of heparin is injected into the catheter through the infusion lumen access port while the elution holes are open to verify and maintain patency of the elution holes. In one embodiment, radio-contrast agent is injected into the blood vessel under radiographic visualization to confirm the vessel anatomy. The bladder tube is deflated prior to injection of heparin and/or radio-contrast agent and reinflated after injection. Radio-opaque interval markers may be positioned about the leg to facilitate localization of any areas of interest visualized by the radio-contrast agent. In another embodiment, Doppler ultrasound is used to confirm vessel occlusion. In one embodiment, use of Doppler ultrasound is preferred because it reduces the need to deflate and reinflate the bladder tube. Reductions in the use of the bladder tube during the procedure may decrease the exposure of the elution holes to the vessel and decrease the risk of occlusion.
The sclerosing agent is prepared as needed and a 20 mL syringe filled with the agent is attached to the infusion lumen access port. In one embodiment, a pressure dressing is applied to the treatment area to enhance vessel wall contact during the infusion of treatment agent. The bladder tube is deflated and an amount of agent is dispensed from the syringe and into the vessel. The bladder tube is reinflated. In one embodiment, the operator reconfigures and/or repositions the catheter for another elution pattern or location, deflates the bladder tube, injects additional agent into the vessel, and reinflates the bladder tube. The cycle is repeated as needed to achieve the desired treatment parameters. In one embodiment, treatment effect is evaluated between injections and additional treatment sites may be identified. In one embodiment, heparin boluses or other anti-coagulation agent are infused through the infusion lumen and elution holes of the catheter after injections of the sclerosing agent or radio-contrast agent to maintain patency of the infusion catheter. The distal balloon of the catheter is deflated and the catheter is withdrawn from the patient. The introducer is removed from the insertion site and hemostasis is achieved by placing one or more non-absorbable sutures to close the insertion site. The insertion site is cleaned with alcohol and dressed. A pressure dressing or wrap is applied around treated limb as needed.
In one embodiment of the invention a kit or system for performing sclerotherapy is provided. In one embodiment, the kit comprises an infusion catheter with an elution zone along at least a 15 cm longitudinal length of the catheter, an infusion syringe and a distal balloon inflation syringe. In another embodiment, the kit comprises an infusion catheter with a plurality of longitudinally arranged elution lumena, 5 ml solution of 1% lidocaine with 1:100,000 epinephrine, an 18-gauge needle and 5 mL syringe, a J-wire, a catheter sheath introducer, a vessel dilator, a treatment agent foaming device, a foam sterilizing filter, a bladder tube syringe, a balloon inflation syringe and a treatment agent infusion syringe. In another embodiment of the invention, the kit or system comprises an infusion catheter capable of accepting a movable wire occluder and a plurality of insertable wire occluders of different configurations.
In one embodiment of the invention, the catheter with a side lumen may be fabricated as a single, integral structure, with the side lumen comprising a longitudinal hole within the sidewall of the catheter. Such a catheter may be manufactured as a dual-lumen catheter by processes including but not limited to extrusion with a dual-air mandrel extrusion tip and die, or extrusion with an air-mandrel tip for the main catheter lumen and a removable wire mandrel for the smaller side lumen. If a wire mandrel, typically made from copper or silver-plated copper, is used to form a lumen, the wire is typically removed from cut lengths of catheter tubing by stretching and breaking the wire to remove the wire from the lumen. One skilled in the art will understand that other such techniques may be used to form catheter tubing with one or more lumena.
The catheter tubing may be made from PTFE, FEP, PFA, Pebax®, polyurethane, nylon, PVC, TPE, polyester and any of a variety of other polymers known in the art. In one embodiment, a catheter material with hydrophobic properties may be preferred, because such materials tend to stabilize foam medicaments better than hydrophilic materials. A single material may be used to form the catheter tubing, or more than one material may be used. In another embodiment, multiple materials are used to form the catheter tubing. In one embodiment, the inner wall material is different from the outer wall material of the infusion catheter. In one embodiment, a tube of a second material may be disposed within the wall of the catheter. In one example, the side lumen of the catheter is first formed by extrusions, then the remaining portions of the catheter are then extrudes with the pre-formed side lumen. In one embodiment, the pre-formed side lumen preferably comprises a material that has a higher melting temperature than the material from which the other portion of the catheter tube is extruded, to reduce melting and/or distortion of the side lumen during the catheter tube extrusion. In one example of a dual-lumen catheter tube, a tubing of FEP or PTFE with an inside diameter of 0.025″ and an outside diameter of 0.031″ is used for the side lumen, which can be incorporated into the wall of an extruded catheter tubing of polyurethane.
In one embodiment of the invention, the elution holes may be formed through thermal punching, wherein a heated wire punch of the desired diameter is pushed through the sidewall of the catheter and withdrawn, leaving a hole. In one embodiment, the temperature of the wire punch is controlled so that when the catheter material is displaced, but adjacent regions of the catheter do not undergo significant melting. In one preferred embodiment, the wire punch is tapered to add stiffness and strength to the wire punch while having the capability of forming smaller holes. For example, a wire may be tapered from 0.008″ to 0.001″ and pushed through the sidewall of the catheter so that the wire penetrates slightly beyond the inner surface of the catheter, resulting in a hole of about 0.002″ at the smallest point. The wire punch can have any of a variety of cross-sectional shapes, including but not limited to circles, ovals, squares, rectangles, other polygons, or a combination thereof.
In one embodiment of the invention, a laser is used to drill from the exterior surface of the catheter, through the side lumen and to the infusion lumen to form the inner holes and outer holes. Small holes, of about 8 microns or less, may be drilled with lasers. Pulse lasers capable of delivering very high power levels for very short periods are preferably used, but such lasers are not required. High power levels and short pulse durations result in ablation, evaporation, and/or photodissociation of the catheter materials rather than melting. Such pulses can be provided with Q-switched YAG lasers at natural frequencies or a multiple thereof, or by excimer lasers, such as xenon fluoride lasers. With high-powered laser drilling, hole size may be controlled by using near-field focusing, beam apertures, and/or focal-length control. In one embodiment, holes may be of substantially constant diameter or may vary in diameter through the wall of the catheter. Larger holes may be formed by defocusing the beam, near-field focusing a larger aperture, and/or by moving either the catheter or the laser beam to remove material and form a larger hole.
In one embodiment, where infusion catheters comprise inner holes and outer holes, the inner and outer holes may be made with different sizes and different methods. In one embodiment, the outer holes may also be formed by catheter manufacturing techniques such as traditional punching, grinding or drilling. The wall thickness of the catheter in the selected location of the hole may also be reduced by skiving, where a portion of the catheter wall thickness is sliced off.
In one embodiment, if the infusion catheter is configured with inner holes that are generally aligned with the outer holes, the inner holes and outer holes may be drilled or punched at the same time as the outer holes.
In one embodiment, wherein the infusion catheter is configured so that the inner holes are not aligned with the outer holes, the inner holes can be formed by laser drilling or thermal punching through the outer catheter wall. The hole through the outer catheter wall may be closed off by thermal sealing or by the use of a sealant, such as a solvent, solvent cement, UV-cure adhesive, epoxy or any of a variety of adhesive materials. In one embodiment, non-aligned inner holes and outer holes may be formed by extruding the catheter tube over a preformed side lumen tube having pre-drilled or pre-punched inner hole lumena.
In one embodiment of the invention, the catheter is constructed with the use of rigid ferrules of metal or hard plastic at the distal end and proximal end of the inflatable occlusion balloon. To maintain a catheter of a small size with the desired flexibility and stiffness to be introduced to the desired location in the body, the catheter body tubing preferably has thickness of about 0.010″ or more to resist collapsing from the pressure of the fiber winding. In other embodiments of the invention, the catheter body tubing has a wall thickness of about 0.004″ to about 0.012″. In one embodiment, thin metal tubing, such as stainless steel extra-thin-wall hypodermic tubing, may be used as a ferrule onto which the balloon is tied and bonded. In one embodiment, silk thread or a plastic ferrule is used to bond the balloon. These ferrules may be bonded to the inflation tubing and sealed within the catheter outer tubing by a sealant, including but not limited to an acrylic adhesive or UV-curable urethane. Such a construction is preferable because it is conducive to good manufacturing practice (“GMP”), as it allows the balloon-ferrule subassembly to be fabricated separately and tested prior to incorporation into the catheter assembly.
To bond the parts of the infusion catheter during the manufacturing process, any of a variety of sealants and adhesives may be used, in addition to welding or other techniques known in the art. In the preferred embodiment of the invention, a UV-cure adhesive is used to bond the subparts of the catheter. To access inner areas of the catheter for bonding, access holes may be provided in the catheter.
To limit the flow of adhesive or sealant into unintended portions of the catheter during the manufacturing process, dams may be used in the catheter design to aid the manufacturing process without reducing the functionality of the catheter. In one example in
There have been described and illustrated herein several embodiments of methods and apparatus for treating the interior of a blood vessel. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, it will be appreciated that the methods and apparatus of the invention may be used in different combinations. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed. For all of the embodiments described above, the steps of the methods need not be performed sequentially.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/US04/03249 | Feb 2004 | WO | international |
This application 1) is a continuation-in-part of U.S. application Ser. No. 10/358,523 filed on Feb. 5, 2003, which is a continuation-in-part of U.S. application Ser. No. 09/898,867 filed on Jul. 3, 2001, which claims priority under 35 U.S.C. §119(e) to a) U.S. Provisional Application No. 60/225,172 filed on Aug. 14, 2000, b) U.S. Provisional Application No. 60/221,469 filed on Jul. 26, 2000, and c) U.S. Provisional Application No. 60/219,931 filed on Jul. 21, 2000, and 2) claims the benefit of priority under 35 U.S.C. 119(a)-(d) to PCT/US04/03249 filed Feb. 24, 2004, which are herein incorporated in their entirety by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60225172 | Aug 2000 | US | |
| 60221469 | Jul 2000 | US | |
| 60219931 | Jul 2000 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10358523 | Feb 2003 | US |
| Child | 10922123 | Aug 2004 | US |
| Parent | 09898867 | Jul 2001 | US |
| Child | 10358523 | Feb 2003 | US |
