Patent Application
20080255447
The present invention relates to medical devices and, more particularly, to an improved diagnostic catheter and method of use.
Catheters are used in a number of medical procedures within various conduits of the body for the purposes of diagnosis and treatment. Typically, catheters have an elongated body with at least one interior lumen which is sized to accept a guidewire. The guidewire is usually inserted first into a patient so that a distal end of the guidewire is positioned at or near a desired target location within the patient. The catheter lumen is fed on to the guidewire, allowing a distal end of the catheter to advance to the target location within the patient.
For example, angioplasty generally includes the steps of inserting a guidewire through a vascular access needle into the femoral or jugular artery or vein and manipulating the external proximal end of the guidewire to advance the distal end of the guidewire through the patient's arterial tree to a predetermined vascular destination.
Achieving a desired location within a patient can be difficult to attain by the feel of the catheter alone and therefore it is often necessary to visualize the anatomical shape of the vessel. One common visualization technique involves injecting contrast fluid into the vessel. A material in the contrast fluid, such as iodine, is visible to X-rays or other radiation and thereby allows the user to visualize the nearby vascular structure. Since the guidewire and the catheter often include radiopaque portions, these devices are also seen relative to the contrast-filled vascular structures. In this respect, the user can visualize the position of their guidewire or catheter relative to the patient's vascular structure and determine if the desired target location has been achieved.
To introduce contrast into the vessel, the guidewire is typically retracted and removed from the lumen of the catheter, allowing contrast fluid to be injected through the lumen of the catheter. The removal of the guidewire prolongs the procedure which increases the risk of complication to the patient. Furthermore, exchanging the guidewire may lead to a loss of the target position at the distal end of the catheter and therefore require additional searching and repositioning. In some procedures it is not possible to reintroduce the guidewire due to spasms of vascular muscles at the target location. In procedures where reintroduction is possible, additional trauma may result at the target location.
Additional disadvantages are also present with diagnostic catheters depending on the location being accessed. For example, existing coronary sinus illumination is currently accomplished by injecting a contrast medium within a single lumen delivery catheter which is placed at or near the ostium of the coronary sinus. Since the injection is made in the opposite direction of the blood flow, the infusion of contrast using this delivery method sometimes results in a resolution that may not be adequate. In this respect, current visualization systems often fail to adequately identify anatomical obstacles within the coronary sinus such as prominent valves near the coronary sinus ostium.
Current diagnostic catheters also lack more specialized functionality such as the ability to cannulate deep within the coronary sinus, for example during a procedure to treat heart valve regurgitation. Currently, the coronary sinus is accessed using angiographic catheters (e.g., 5 or 6 Fr Judkins Right JR4 coronary aniography catheter) to position the tip of the catheter at the ostium of the coronary sinus. The limitations of these devices are that since its intended use is for angiographic purposes, the tip curvature is not ideal to access the coronary sinus and thus make it difficult to cannulate. After locating the ostium, a guidewire is inserted into the diagnostic catheter from the proximal end and used to track to the great cardiac vein by manipulating (e.g., via torquing) the proximal end of the guidewire. The challenge with this technique lies with the difficulty of directing the guidewire tip into a desired side branch within the coronary sinus without causing the guidewire to become stuck or hung up. Current angiographic catheter tips are unable to advance deep within the coronary sinus due to their necessary rigidity. Thus, after the guidewire is positioned within the great cardiac vein, the angiographic catheter is withdrawn and exchanged for the over-the-wire guide/dilator catheter. The dilator is withdrawn when the guide catheter reaches a position at the ostium. This method of exchange increases procedural times and possible risk or errors. Additionally, when a guidewire is utilized to navigate deep within the coronary sinus, there is a risk for soft tissue damage such as tearing or piercing of the coronary sinus.
Thus, there is a need to provide an improved diagnostic catheter that is easier to use, reduces the number of guidewire exchanges during a procedure, decreases the likelihood of causing trauma to the patient and provides improved contrast visualization.
It is an object of the present invention to provide an improved diagnostic catheter that overcomes the limitations of the prior art.
It is a further object of the present invention to provide a diagnostic catheter that decreases the likelihood of causing trauma to the patient during a procedure.
It is yet another object of the present invention to provide a diagnostic catheter that provides improved contrast visualization over prior art catheters.
An aspect of some preferred embodiments of the present invention relates to a diagnostic catheter having both a guidewire lumen and at least one contrast lumen. These lumens allow the user to deliver contrast to a target area within the patient without removing the guidewire.
In another aspect of some preferred embodiments of the present invention, multiple contrast lumens are included within the diagnostic catheter, maintaining structural integrity and kink resistance within the catheter body while providing a consistent flow of contrast to a target location.
In yet another aspect of some preferred embodiments of the present invention, a plurality of contrast exit ports are included along the length of the catheter body to more evenly and consistently distribute contrast into the blood stream, thereby providing improved visualization during radioscopy.
The catheter 100 has a generally elongated body 108 that includes regions 126, 128 and 130. Preferably, each region 126, 128 and 130 is progressively more flexible than the next, allowing regions 128 and 130 to better conform to the tortuous pathway of the patient's vascular system while minimizing any trauma cause by the distal end of the catheter 100. This feature is advantageous as compared with prior art measurement catheters which are more rigid and therefore may reshape the anatomy when advanced through the vascular system of a patient.
In one example, the region 126 is about 70 cm in length and composed of a high density polyethylene with a Durometer between about 58 and 72 Shore D, the region 128 is about 15 cm and composed of a 50/50 polyethylene having a Durometer between about 55 and 63 Shore D and the region 130 is about 5 cm and composed of a low density polyethylene with a Durometer between about 41-60 Shore D.
As best seen in the cross sectional view of
The catheter is generally configured and sized to minimize kinking of the contrast lumens while maintaining adequate contrast flow to the exit ports 112. In a more specific example of such a configuration, referring to
Referring to
In operation, the user advances a guidewire into the vascular system of a patient until a distal end of the guidewire is thought to be positioned near a desired target location. The catheter 100 is then fed over the guidewire so that a proximal end of the guidewire passes into the exit port 118, through the guidewire lumen 110 and out the port 102.
When the user wishes to visualize the location of the guidewire and catheter 100 relative to the patient's vascular structure, contrast media is injected into the injection port 104, passing down the contrast lumens 120 and out the exit ports 112. Radioscopy is performed, exposing the patient to radiation, such as X-rays, to generate an image of the relative position of the guidewire and catheter 100 in the patient.
While the catheter 100 is illustrated with four contrast lumens 120, it should be understood that greater or fewer contrast lumens 120 may be included according to alternate preferred embodiments of the present invention. For example, the catheter 100 may include 2, 3, 4, 5 or 6 contrast lumens 120.
In some procedures, a measuring guidewire is used; having a plurality of radiopaque markers spaced at known intervals along its length. These markers allow the user to measure vascular features or positions within the patient during a visualization technique. In contrast, the present diagnostic catheter 140 integrates these measuring markers 116 into the body 108, allowing the user to make measurements during a visualization procedure while using an ordinary guidewire. In this respect, the user is free from removing the ordinary guidewire and replacing it with a measuring guidewire during a procedure. This reduces the trauma induced from the guidewire switch, reduces the time required for the procedure, and finally reduces the expense of the more expensive measuring guidewire.
The markers 116 are preferably embedded into the body 108, so as to have the same outer diameter as other portions of the body 108. In one example, the markers 116 are arranged along the length of the catheter in 1 cm increments along the distal end of the catheter 100 for about 25 cm. In a further example, the markers 116 have a band shape around the diameter of the body 108, a width between 0.001-0.002 inches, and a composition of platinum, iridium or gold.
Referring to
Referring now to
Current dispersion catheter technology typically pertains to delivery of drug therapy and dispersions of therapeutic solutions for pulse and slow infusion delivery. In contrast, the plurality of diffusion ports 162 more widely disperses contrast solution to aid in the identification of anatomical features, such as heart landmarks, vascular navigation, coronary sinus identification, cannulation, measurement and deep navigation. In a further example use, the improved contrast dispersion may improve identification of obstacles to coronary sinus cannulation such as prominent valves such as the thebesian, coronary venous and the valve of vieussen at the transition between the coronary sinus and great cardiac vein.
Preferably these diffusion ports 162 have a circular shape, oval shape, slit shape or any combination of the three. These ports 162 can be located at different positions around the circumference of the body 108 to achieve different contrast dispersion patterns. For example, the ports 162 may be located at 45, 60 or 120 degree intervals around the circumference of the body 108. Further, the sizes of the ports 162 may increase or decrease along the length of the catheter 160. Such a port diameter gradient may be configured to compensate for decreasing contrast pressure toward the distal end of the catheter 160 or configured to disperse different amounts of contrast along the length of the catheter 160. Additional delivery port information can be found in U.S. Publication No. 2006/0064011, the contents of which are hereby incorporated by reference.
In one example, the plurality of ports 162 are situated along a length of the catheter 160 of about 20 cm and have a port diameter of about 0.5 mm and are positioned at 120 degree intervals around the circumference of the body 108.
In addition to the plurality of radiopaque markers 116 placed at regular intervals along the catheter 160, the catheter body 108 may also include radiopaque graduations for further indicating length measurement during radioscopy. These graduations may be created, for example, by imbedding radiopaque markers within the body of the catheter, hot stamping radiopaque ink into the catheter body or impregnating regions such as the distal tip with a radiopaque compound. The atraumatic tip 164 of the catheter 160 may also include radiopaque materials to better define the distal end of the catheter 160 during a visualization procedure.
Optionally, the catheter 160 may include inflatable balloons to aid with navigation, dilation or provide diametric measurements (e.g., a balloon may be distended to a set diameter using a predetermined volume as a diametric estimator). Further, a balloon may be used as a positioning tool, for example to change the trajectory of a catheter and especially to “kick” the catheter to one side when a bifurcation is encountered.
Turning to the example of
In another example,
Additionally, the occlusion balloon 165 may be used as a reference point by contacting various structures within the patient. For example, when expanded, the occlusion balloon 165 may contact the ostium of the coronary sinus 258, thereby providing a tactile indication to the user that the catheter 160 has been fully inserted into the coronary sinus 258.
In alternative configurations, the occlusion balloon 165 may be configured to slide relative to the catheter 160 to adjust the balloon position relative to the distal end of the catheter 160 or to measure different features within the patient. For example, the occlusion balloon 165 can be attached to an outer sheath (not shown) that surrounds and therefore slides relative to the catheter 160.
Additionally, the body 108 of the catheter 160 may include braiding wire material (e.g., 304 or 316 grade stainless steel with wire diameter ranges of about 0.001-0.004 inches if rounded and 0.003-0.008 inches if flat wire) for improved torque control and pushability during insertion and manipulation of the catheter 160.
In another preferred embodiment seen in
As seen in the cross sectional views of
The wire braid layer 205 is included between the inner polymeric layer 203 and outer polymeric layers 201 of the diagnostic catheter 200, positioned along some or all of the catheter length. For example, the braided composite may be composed of polymeric filaments such as PET, Kevlar, Vectran or metallic wires and these wires preferably have a round diameter from about 0.0005-0.007 inches or a flat profile in the range of about 0.0005″×0.003″ to 0.003″×0.007″. The braid density can be increased to increase the rigidity of the catheter 200 (e.g., between about 30-80 picks per inch).
As previously indicated, the diagnostic catheter 200 has variable flexibility along its length so that the flexibility progressively increases towards the distal end of the catheter 200. For example, the diagnostic catheter 200 may have a distal segment with a firmness between about 25-72 Durometer shore hardness, an intermediate transition segment with a firmness between about 25-72 Durometer shore hardness (but greater than the distal segment), and a proximal segment with a firmness between about 40-72 Durometer shore hardness (greater than the intermediate transition segment).
The tips of the catheters 200 and 202 have a predetermined curve shape which allows a user to more easily direct the distal end of the catheter 200 and 202 into the side branches of the coronary sinus. Preferably, the curves of these angle ranges are between about 30-100 degrees. In one example, a catheter includes a distal region with a curve radius of about 1.50 inches across a 90 degree span. In another example, a catheter includes a distal curve having a radius of about 1.15 inches followed by an opposing intermediate curve having a radius of about 0.8 inches followed by an opposing curve having a radius of about 1.15 inches forming a generally question mark shape.
As seen in
It should be noted that the catheters 100, 140, 150, 160, 170, 200, 202, 204, 206, 208 and 210 can be used with a variety of different procedures that require visualization techniques, such as neural procedures, mitral annuloplasty procedures or other procedures that involve access to the coronary sinus or more generally the heart. It should be further noted that any of the features of the different embodiments described in this specification may be combined with features shown on other embodiments.
Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.
