Patent Application
20070167924
The present invention relates generally to an intraluminal guiding catheter used during interventional catheterization, and more particularly, to a guiding catheter with a selectively inflatable eccentric balloon for supplementing back-up force provided by a pre-shaped curve in a distal region of the catheter.
A stenosis, lesion, or narrowing of a blood vessel such as an artery may comprise a hard, calcified substance and/or a softer thrombus material. There have been numerous interventional catheterization procedures developed for the treatment of stenoses in arteries. One of the better-known procedures is percutaneous transluminal coronary angioplasty (PTCA). According to this procedure, a narrowing in a coronary artery can be expanded by positioning and inflating a dilatation balloon across the stenosis to enlarge the lumen and re-establish acceptable blood flow through the artery. Additional therapeutic procedures may include stent deployment, atherectomy, and thrombectomy, which are well known and have proven effective in the treatment of such stenotic lesions.
In cases where the lesion targeted for treatment is located distant from a convenient vascular access location, the therapeutic procedure typically starts with the introduction of a guiding catheter into the cardiovascular system from an easily reachable site, such as through the femoral artery in the groin area or other locations in the arm or neck. The guiding catheter is advanced through the arterial system until its distal end is located near the stenosis that is targeted for treatment. During PTCA, for example, the distal end of the guiding catheter is typically inserted only into the ostium, or origin of a coronary artery. A guidewire is advanced through a main lumen in the guiding catheter and positioned across the stenosis. An interventional therapy device, such as a balloon dilatation catheter, is then slid over the guidewire until the dilatation balloon is properly positioned across the stenosis. The balloon is inflated to dilate the artery. To help prevent the artery from re-closing, a physician can implant a stent inside the dilated portion of the artery. The stent is usually delivered to the artery in a compressed shape on a stent delivery catheter and is expanded by a balloon to a larger diameter for implantation against the arterial wall.
Guiding catheters typically have a pre-shaped curve that is sized and shaped for positioning in a main vessel to orient or direct the distal end of the catheter into the entrance to a branch vessel. PTCA guiding catheters, for example, have a pre-shaped curve that fits within the aortic root and/or the ascending aorta for positioning the distal end of catheter near or within the ostium of a left or right native coronary artery or a bypass graft, depending on the curve selected. Many pre-shaped guiding catheter curves are also sized and shaped to span the width of the main vessel to support branch vessel intubation from a main vessel wall location that is contralateral, or generally opposite to the ostium of the branch vessel.
At times it is difficult to advance the interventional catheter across the stenosis because the narrowing may be very tight or the vessel(s) may have significant bends to be negotiated between the ostium and the target stenosis. In such difficult cases, the guiding catheter can fail to provide sufficient structural support or “backup” as the interventional catheter is pushed distally against resistance. In failing to provide backup support, the guiding catheter reacts to the attempted crossing forces by deforming the pre-shaped curve such that the catheter tip “backs out,” proximally from its initial position at the ostium of the branch artery. When the guiding catheter distal end remains in a fixed position, it facilitates the ability to advance the interventional catheter. As guiding catheters have advantageously evolved to have thinner walls and smaller outside diameters, it has been increasingly challenging to provide the necessary “backup support” in all clinical cases.
Catheter systems that may be utilized to increase the backup support of a conventional guiding catheter are known. In some examples, guiding catheters have one or more wire loops or leg members that may be extended against a vessel wall for bracing against forces tending to back the catheter tip out of a contralateral branch vessel. However, such wire loops may focus bracing forces in a small area, possibly embedding the loops into the vessel wall or otherwise causing injury. Disposing such wire elements near the distal end of a guiding catheter also can hinder the formation of desired curve shapes during manufacturing of the guiding catheter.
Another known guiding catheter having increased backup support includes a balloon disposed around the guiding catheter distal end that may be inflated within the ostium of a coronary artery to temporarily anchor or lock the catheter tip in place. However, inflating a balloon within the ostium of a vessel undesirably occludes blood flow into the vessel for the duration of the inflation.
There is a need to selectively reinforce the position of the distal end of a guiding catheter in its position in the ostium of a branch vessel, so that an interventional catheter can be housed therein and advanced distally into the branch vessel or a tributary vessel thereto without losing structural support or backup from the guiding catheter. The guiding catheter should have a supplemental back-up support system having minimal chance of injury to the vascular system. It is desirable for the supplemental back-up support system to be operable without occlusion of the main vessel or the intubated side branch. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims taken in conjunction with the accompanying drawings.
The invention provides a guiding catheter including an elongate shaft with a main lumen and a pre-shaped curve adjacent the distal end of the shaft. The pre-shaped curve is sized and shaped for positioning in a main vessel to provide intubation of a branch vessel with a distal end of the catheter. An eccentric balloon is disposed on the shaft for selective inflation against a wall of the main vessel generally opposite the entrance into the branch vessel to provide supplemental backup support during interventional catheterization of the branch vessel. The eccentric balloon inflates away from the catheter shaft generally in one direction and does not inflate sufficiently to span, and thus occlude the main vessel.
A method is disclosed for using the inventive guiding catheter with selectively inflatable eccentric balloon. The method includes providing a guiding catheter having the embodiment described above; inserting the guiding catheter into a main vessel of a patient such that the catheter distal end intubates a side branch off of the main vessel; and inflating the balloon against a main vessel wall portion contralateral to the side branch vessel to reinforce the intubation of the shaft distal end in the side branch without occluding fluid flow through the main vessel.
In other embodiments of the invention, the method may also include: inserting a therapeutic device through the main lumen of the guiding catheter; positioning the therapeutic portion of the therapeutic device across the stenosis; and treating the stenosis with the therapeutic device.
The following drawings are illustrative of particular embodiments of the invention and therefore do not limit its scope. They are presented to assist in providing a proper understanding of the invention. The drawings are not to scale and are intended for use in conjunction with the explanations in the following detailed descriptions. Like reference numerals denote like elements in the drawings, wherein;
Specific embodiments of the present invention are now described with reference to the figures. The terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to the treating clinician. “Distal” or “distally” are a position distant from or in a direction away from the clinician. “Proximal” and “proximally” are a position near or in a direction toward the clinician.
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Although the description of the invention is in the context of treatment of blood vessels such as the coronary, carotid and renal arteries, the invention may also be used in any other passageways where it is deemed useful to selectively provide backup support for a pre-curved guiding catheter. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
As described above, if the interventional catheter encounters high resistance when pushed into coronary artery 280, then the guiding catheter may react by distal end 105 “backing out” from its initial position at ostium 270 and deforming pre-shaped curve 110. To prevent distal end 105 from backing out of ostium 270, pre-shaped curve 110 spans the aorta from ostium 270 to the opposite or contralateral aortic wall. Pre-shaped curve 110 would typically contact the aortic wall opposite ostium 270 along buttress region 290, which is located somewhat superior to the level of ostium 270.
In accordance with the invention, the backup support provided by pre-shaped curve 110 can be selectively supplemented by inflating eccentric balloon 150 away from shaft 102 in second direction 160. As eccentric balloon 150 is inflated against buttress region 290, catheter shaft 102 is forced away from buttress region 290, as shown in
Balloon 150 is mounted eccentrically to shaft 102 and is shown in
Balloon 150 may be a patch of thin elastic material having its perimeter bonded eccentrically to shaft 102 around port 156. Balloon 150 may be formed from an elastic material such as latex, silicone elastomer, or other viscous forms of natural and synthetic rubbers such as butadiene/acrylonitride copolymers, copolyesters, ethylene vinylacetate (EVA) polymers, ethylene/acrylic copolymers, ethylene/propylene copolymers, polyalkylacrylate polymers, polybutadiene, polybutylene, polyethylene, polyisobutylene, polyisoprene, polyurethane, styrenebutadiene copolymers, and styrene-ethylene/butylene-styrene. Alternative embodiments of eccentric balloon 150 are possible, including a short tubular balloon mounted off-center or alongside shaft 102. Balloon 150 may also comprise a thin, flexible, foldable, inelastic material such as polyamide, polyethylene, polypropylene, polyurethane, polyesters, or polyethylene block amide copolymer, or polyethylene terephthalate. Balloon 150 may be attached to shaft 102 using any suitable manner known in the art, such as adhesive bonding or heat bonding. During use, it is preferred that eccentric balloon 150 not be sufficiently inflated to fully occlude a main vessel, such as the aorta, even if the size, shape and/or expansibility of balloon 150 would allow such inflation.
Catheter shaft 102 is a flexible tube that is designed to advance through a patient's vasculature to remote arterial locations without buckling or undesirable bending. Any one of a number of pre-shaped curves may be incorporated into guiding catheter 100, such as Judkins-type or Amplatz-type curves, as non-limiting examples. Curve 110 may be pre-shaped utilizing various known methods including, but not limited to, the method disclosed in U.S. Pat. No. 5,902,287 entitled “Guiding Catheter and Method of Making Same.”
Catheter shaft 102 may be constructed of one or more flexible biocompatible materials, including, but not limited to polyamide, polyethylene, polypropylene, polyurethane, polyesters, or polyethylene block amide copolymer. Catheter shaft 102 may also include layer 180 of braided filaments that resist kinking and enhance longitudinal transmission of rotation. To further aid in advancing guiding catheter 100 through the patient's vasculature, it may be desirable to vary the stiffness of catheter shaft 102 by varying the braid pitch, by varying the properties of materials used in construction, or by combining both techniques.
Main lumen 140 of guiding catheter 100 may provide a slippery interior surface for reducing frictional forces between the interior surface and devices that may be moved through main lumen 140. In one exemplary embodiment, the interior surface is provided with a slippery coating, such as a silicone compound or a hydrophilic polymer. In another exemplary embodiment, the interior surface includes a liner formed from a slippery material. Those with skill in the art may appreciate that any one of numerous low-friction, biocompatible materials such as, for example, fluoropolymers (e.g. PTFE, FEP), polyolefins (e.g. polypropylene, high-density polyethylene), or polyamides, may be used for main lumen 140.
As shown in
Inflation fitting 154 is also coupled to the proximal end of shaft 102 and has an opening in fluid communication with inflation lumen 158. A source of inflation fluid (not shown) may be connected to inflation fitting 154 for inflating and deflating eccentric balloon 150. Suitable inflation fluids may include carbon dioxide gas or dilute radiographic contrast media. Fitting 154 may be made of the same or similar material as those mentioned above with respect to connector fitting 130, or fitting 154 may be integrally formed therewith.
As described above, if the interventional catheter encounters high resistance when pushed into coronary artery 580, then the guiding catheter may react by distal end 405 “backing out” from its initial position at ostium 570 and deforming pre-shaped curve 410. To prevent distal end 405 from backing out of ostium 570, pre-shaped curve 410 spans the aorta from ostium 570 to the opposite or contralateral aortic wall. Pre-shaped curve 410 would typically contact the aortic wall opposite ostium 570 along buttress region 590, which is located somewhat superior to the level of ostium 570.
Similar to guiding catheter 100, the backup support provided by pre-shaped curve 410 can be selectively supplemented by inflating eccentric balloon 450 away from shaft 402 in second direction 460. As eccentric balloon 450 is inflated against buttress region 590, catheter shaft 402 is forced away from buttress region 590, as shown in
Only when catheter curve 410 is disposed at the intended location in the patient's body, i.e. in the ascending aorta with distal end 405 located at ostium 570, then second direction 460 is generally parallel, offset and opposite first direction 420, as shown in
An exemplary method of using guiding catheter 400 will now be described with reference to
If attempts to push PTCA catheter 700 through stenosis 575 meet with sufficiently high resistance such that guiding catheter distal end 405 backs out of ostium 570, then the clinician may elect to inflate eccentric balloon 450 to supplement the inherent backup support already provided by pre-shaped curve 410 of guiding catheter 400. A source of balloon inflation fluid (not shown), such as a syringe and stopcock may be connected to inflation fitting 454. The clinician operates the source of fluid to inflate eccentric balloon 450 against buttress region 590 of the aorta. Varying the amount of fluid injected into the interior of balloon 450 will adjust the extent to which catheter shaft 402 is deformed away from buttress region 590 of the aorta, thus varying the amount of backup support supplemented to pre-shaped curve 410 of guiding catheter 400.
When sufficient backup support is provided by guiding catheter 400, then PTCA catheter 700 may be forced into stenosis 575 and inflated therein, as shown in
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof. For example, the invention is applicable to a large variety of pre-shaped guiding catheter curves. When the catheter is placed in the patient, an eccentric balloon can selectively provide supplemental backup support by being inflated in a direction that is generally opposite to the open catheter distal end.
