The present invention relates generally to restoration of flow capacity to occluded and partially occluded vessels, including arteries, and more particularly to a procedure by which at least an interior lining is in the form of a vascular graft placed in an artery as an anti-stenotic measure.
During the last thirty (30) years the most common technique for treating arterial stenosis has been surgical construction of a bypass conduit around the site of the occlusion. Bypass grafting in a symptomatic patient with a partially or totally occluded or stenotic superficial femoral artery, using a vein or prosthetic graft, has been the dominant technique for arterial reconstruction. Endarterectomy is also performed in some cases.
In the last decade balloon catheter angioplasty of patients with focal stenosis has demonstrated benefit primarily because of its minimal invasiveness, thereby reducing cost and recovery time. It is, however, limited to short focal stenoses through which the balloon can be positioned. It has a significant rate of restenosis in longer or diffuse lesions, where its use is not indicated. To address these limitations and to improve the treatment of longer length segments of occlusive disease, a variety of catheter based laser and mechanical atherectomy devices have recently been developed and studied. The hope has been to obtain the benefits of reducing costs, morbidity, and recovery time available from using less-invasive, catheter-based methods while still obtaining the overall good patient results comparable to by-pass grafting. Despite these efforts, by-pass grafting has remained the technique generally used in clinical practice, due to its superior overall results compared to the novel catheter-based techniques heretofore developed. The present invention overcomes or substantially alleviates the limitations of previous catheter-based techniques for treating SFA disease, while obtaining the benefits of proven by-pass grafting techniques.
In brief summary, the present invention overcomes or substantially alleviates the above-mentioned pre-existing problems. The present invention provides for removal of all or nearly all atheroma from within an arterial segment of any length and then placement of a vascular graft, which may be of any suitable material, with only one point of entry. The atheroma alone can be removed or the atheroma and the tunica intima alone or together with the tunica media of the arterial segment can be removed. Other vessels can also be treated and vascularly lined without departing from the scope of the invention. The present invention provides the benefits of minimally invasive surgery, overcomes or substantially alleviates the limitation of recurrent stenosis, and allows treatment of any occlusive lesion regardless of length.
Thus, normal capacity blood flow is provided with no or low probability of recurring stenosis. While the present invention has been applied to occlusion in the superficial femoral artery, it is not limited to any particular artery diseased by stenosis.
With the foregoing in mind, it is a primary object of the present invention to provide an antistenotic method and product by which substantially full blood flow capacity is restored to a wholly or partially occluded artery.
Another object of importance is the provision of a method and product by which an atheroma is removed from an artery and provision is made to prevent or alleviate the likelihood of a later redevelopment of another atheroma at the removal site.
A further significant object is to provide a method and product by which substantially full blood flow is surgically restored to a stenotic artery.
Another dominant object is the provision of a method and product which substantially eliminates an atheroma from an artery and eliminates or significantly reduces the likelihood of restenosis at the prior atheroma site.
An additional object of substantive importance is the provision for removal of stenotic deposits from an artery with or without removal of an interior portion of the artery followed by insertion of a vascular graft along the length of the removal site as an anti-stenosis measure.
One more object of value is the provision of a method of and product for substantially removing stenotic deposits in an artery and substantially preventing or alleviating recurrence thereof independent of the arterial length of the deposits.
An additional paramount object is the provision of a novel method and product by which a vessel of a medical patient is lined for the purpose of establishing and/or maintaining full blood flow.
These and other objects and feature of the present invention will be apparent from the detailed description taken with reference to the accompanying drawings.
The Figures described briefly below are line drawing schematics, predicated upon the existence and commercial availability of the various devices and apparatus as shown therein.
The illustrated embodiments demonstrate and are representative of methods by which a partially or totally occluded artery or other vessel of a patient is recanalized and the risk of restenosis is substantially reduced or eliminated by use of a vascular graft within the treated artery.
While the present invention may be used in a vessel other than an artery, the primary benefit lies in application to an artery. Artery flow is either conduit or branch flow. The iliac, femoral, and more distal arteries are most likely to occlude, either totally or partially. All arteries are strong, durable, three-layer vessels while veins are thin, single layer conduits. The arterial wall layers are, inside out, the tunica intima endothelium (intima), the tunica media (media), and the tunica adventitia (adventitia). It has been found that in diseased arteries typically the interface between the adventitia layer and the media layer becomes a region of naturally occurring weakness. In fact, it has been found that plaque not only accumulates within the lumen of the artery but infiltrates both the intima and media causing a tissue breakdown there.
Removal of the intima and the media from the adventitia and leaving the adventitia of the artery is called an endarterectomy.
The primary cause of artery occlusion is build-up of plaque, the density of which ranges between very soft to rock-hard calcified deposits. Plaque deposits may form in some arteries and not at all or slightly in other arteries of the same person. A plaque deposit in a specific area or region of an artery is sometimes called an atheroma.
Under appropriate anesthesia the artery is exposed, clamped, and at least a single arteriotomy is performed distal to the clamp and proximal to the occlusion. Under some circumstances two arteriotomies are performed, one upstream and the other downstream of the atheroma although a single arteriotomy is preferred. In some situations access to the artery can be by use of percutaneously placed hollow needle, instead of by use of an arteriotomy.
In situations where an arteriotomy is the preferred choice, a guide wire is advanced through an upstream arteriotomy until the guide wire extends beyond the atheroma. Sometimes a guide wire can be advanced through a clogged artery, but not always. In situations where a guide wire alone cannot cross the atheroma, a dynamic wire guide or a dynamic dirupter is preferably used to centrally loosen and/or displace the centrally disposed plaque followed by central insertion of the guide wire through the hollow interior in the dynamic wire guide or disrupter. Thereafter, the dynamic wire guide or disrupter is removed.
Any technique by which the plaque is severed from the inner wall of the intima is called an atherectomy. Typically, plaque may be so severed by a coring catheter or by using an atherotome having one or more expandable blades to accommodate insertion and one or more passes through the atheroma, each pass at an increased blade diameter.
Atherectomy devices such as a Simpson Atherocath, an Auth Rotablator, a Kensey device, or an Intervertional Technologies Transluminal Extraction Catheter (TEC device) may be used.
In some situations an endarterectomy is the preferred medical choice. For example, an endarterectomy is often best when the disease of the artery is substantially advanced, causing a natural interface of weakness between the media and the adventitia. A cutting atherotome may be used to initially cut through the diseased intima and media to the adventitia at the distal end of the site of the endarterectomny creating a taper at that location followed by advancement in a proximal direction until the entire undesired length of intima and media have been excavated. Alternatively, the intima and media may be cut radially or on a bevel adjacent both a first and second arteriotomy located above and below the atheroma. Ideally, a taper is used at both ends of the endarterectomy where the enlarged lumen produced connects across a beveled tapered to the normal lumen of the artery, both distally and proximally the dispensed material is loosened from the wall using any suitable instrument, such as a surgical spatula. Forceps may be used to grasp and pull upon a loosened part of the intima and media to be removed causing the intima and media between the two cuts together with the ateroma contained therein to be removed from the artery as a cylindrical unit.
Alternatively, a Hall loop may be advanced from one arteriotomy to the other after the two above-mentioned cuts have been made. The loop, in the nature of a piano wire loop held on the end of a staff is positioned at the above-mentioned natural interface of weakness. The loop is positioned and displaced along the interface by pushing on the staff until the intima, the media, and the atheroma to be removed have been unitarily severed following which the cylindrical unit may be grasped and removed from the artery using forceps, for example.
Similarly, a Scanlan Endarsector or a cutter having rotating blades may be used to assist in the performance of the endarterectomy.
In situations where an angioplasty, in whole or in part, is the treatment of choice, an instrument of expansion is used to enlarge or open and enlarge the blood flow accommodating lumen at the atheroma. Mechanical instruments, equipment for performing balloon angioplasty, laser instruments, and instrumentation for ultrasound angioplasty may be used to achieve the angioplasty.
Once the plaque has been excavated, steps are taken to line the remaining treated arterial or vessel wall. The resulting lining is herein referred to as a vascular graft. Vascular graft, as used herein, is intended to mean any of the following: 1. conventional and novel artificial grafts made of any material, including but not limited to fabrics such as dacron, or expanded PTFE Gortex™ thin wall sleeve material, in any density from very soft and low density to very stiff and high-density, constructed in any shape including straight, tapered, or bifurcated, and which may or may not be reinforced with rings and spirals or other reinforcement, and which may or may not have one or more expandable stents incorporated into the graft at one or both ends or along its length, 2. natural artery or vein material taken from human or animal donors, 3. stents, 4. coating applied to the inside of the treated arterial wall which forms a patent lumen or is biologically active and causes the lining of the vessel or duct to form a patent lumen, and 5. any combination of the foregoing vascular graft options. The exterior of the vascular graft or part of it may and preferably does comprise tissue in-growth material. Where a pre-formed tubular vascular graft of synthetic material is used, the material thereof may be and preferably is dimensionally stable. However, if desired, it may be radially expandable material.
The vascular graft of choice may be introduced into the treated artery or other vessel in any suitable way including but not limited to use of a dilator/sheath, placement of the vascular graft upon a mandrel shaft and/or use of long-nose forceps. The distal ends of the tubular graft and the mandrel shaft may be temporarily sutured together or the distal end of the vascular graft sutured together over the mandrel to accommodate unitary displacement into the vein, for example through a sheath after the dilator has been removed.
Where the material of which the vascular graft is formed is expandable and in tubular or sleeve form, once the sheath has been removed the diametral size of the graft may be enlarged in contiguous relationship with the inside arterial surface using a balloon catheter. A balloon catheter may also be used to bring a folded or partially collapsed vascular graft which is dimensionally stable into contiguous relation with the interior surface of the remaining artery wall.
The tubular graft may also comprise a biologically inert or biologically active anti-stenotic coating applied directly to the treated area of the remaining arterial inner surface to define a lumen of acceptable blood flow capacity.
The graft, once correctly positioned and contiguous with the interior vascular wall, is usually inherently secure against inadvertent migration within the artery or other vessel due to friction and infiltration of weeping liquid accumulating on the inside artery wall. It is preferred that the length of the vascular graft be selected to span beyond all of the treated region of the artery.
One or both ends of the vascular graft may be sutured or surgically stapled in position on the treated wall to prevent undesired displacement or partial or complete collapse under cardiovascular pressure. In particular, the upstream end of a graft placed in an artery must be secure to prevent a flap of the graft from being pushed, by arterial blood flow, into a position where it occludes, in whole or in part, the vessel. One or both ends may be held open by one or more stents disposed within the tubular graft. Forceps may be used to hold a free end of the vascular graft while the other end is secured to the vascular wall. Currently, it is preferred to secure the proximal end of the tubular vascular graft to the treated vascular wall and to bias dilate the distal end of the tubular vascular graft by use of a balloon catheter and/or arterial pressure. Where the distal exterior of the sleeve-shaped vascular graft comprises tissue in-growth material, as is preferred as in-growth occurs it becomes immaterial how the initial dilating bias was achieved.
Reference is now made to the drawings wherein like numerals are used to designate like parts throughout. While the drawings are specifically directed toward the removal of an atheroma in the superficial femoral, it is to be appreciated that the principles of the present invention apply to other arteries as well as to ducts and vessels in the body other than arteries. Specifically,
While
Typically, as illustrated in
Once the dynamic wire guide 64 has penetrated the central plaque region 56 so as to traverse the hard plaque portion 58, the guide wire 62 is advanced through the lumen within the dynamic wire guide 64, following which the dynamic wire guide is withdrawn leaving the guide wire 62 in position, as a guide for instruments by which the soft and hard plaque 56 and 58 are removed.
Alternatively, with reference to
While not shown, it is to be appreciated that plaque, separated from the atheroma 54, cannot be allowed to remain uncollected within the artery and, therefore, conventional instruments and procedures are used appropriately downstream of the atheroma 54 to collect and remove all debris released during treatment of the atheroma 54.
Having established the appropriate placement of guide wire 62 through the atheroma 54, the surgeon is in a position to enlarge the arterial lumen at the site of the atheroma 54 by removing plaque 58. Such removal is commonly referred to as an atherectomy. The severing, grinding, cutting, chipping, and abrading of the plaque 58 may be mechanically accomplished by any suitable cutting instrument. Exemplary types are illustrated in
Either in conjunction with a coring catheter or in lieu thereof, the lumen across the atheroma 54 can be enlarged using an expandable cutter, having diametrally expandable cutting blades as illustrated in
Attention is now turned to those situations where an endarterectomy is the procedure of choice. Specific reference is now made to
While not illustrated in all of the Figures (for simplicity of presentation), it is to be appreciated that all arteries comprise three layers, the intima, the media, and the adventitia.
It is to be understood that the distinction between atherectomy and endarterectomy is somewhat arbitrary, as it depends upon whether the material being removed consists exclusively of atheroma only, or of a combination of atheroma and material characteristic of the inner lining of the vessel. Pathology analysis of such removed material frequently indicates the presence of cells and other material characteristic of both plaque and the media and intima, so it is probably most correct to refer to this procedure as an endarterectomy.
In one currently preferred embodiment, an endarterectomy is performed using the dynamic disrupter and the expandable cutter. The dynamic disrupter is first advanced over the guide wire both to loosen the plaque and the intima and media along the natural interface of weakness, and to enlarge the channel or lumen through the artery. The dynamic disrupter may be advanced one or more times. If multiple advances are used, the repeated advancements may be done using the same tip size, or they may be done using successively larger tip sizes.
After the dynamic disrupter has been used and withdrawn over the guide wire, the expandable cutter is employed to remove the material that has been loosened. With the blades unexpanded, the expandable cutter is advanced a suitable distance into the atheromatous region, and then the blades expanded. When the expandable cutter is withdrawn, it engages the plaque and arterial lining, and exerts force upon the natural interface of weakness. The plaque and arterial lining are withdrawn by the expandable cutter in the form of a cylindrical plug of material, which may be short or long depending upon how far into the plaque the cutter is advanced before it is expanded. After removing the plug of material from the cutter, the blades are returned to the unexpanded position and re-advanced into the artery, this time to a position further than the previous advancement, so that a new length of atheromatous material can be engaged. The blades are once again expanded, and a new plug of material is engaged and withdrawn. By a repeated series of such steps, any desired length of artery may be excavated of its plaque and inner lining. When the final advance to the most distal point is performed, the distal tapered shape that the blades assume when expanded leaves behind the desired tapered shape as it cuts and removes the final plug of material from the artery. This eliminates any need to make the second arteriotomy 50′, for the purpose of making the distal radial cut, when the expandable cutter if employed.
In the alternative, an endarterectomy may be performed using a Hall loop, as diagrammatically illustrated in
The endarterectomy may similarly be performed using a Scanlan Endarsector, as generally illustrated in
Reference is now made to
With specific reference to
Reference is now made to
In lieu of the above-mentioned ways for performance of an atherectomy, or in conjunction therewith, ultrasound energy may be used. Specific reference is made to
Once the interior of the partially or totally occluded artery has been treated using an appropriate procedure including one or more of the procedures described above, the present invention includes placement of a lining or vascular graft so as to extend preferably co-extensively along the full length of the treated portion of the artery. The nature of the vascular graft will vary depending upon the circumstances, the artery in question, the length over which the artery has been treated, and perhaps other factors. The vascular graft may be of any suitable biologically inert material including, but not limited to, a dacron sleeve of medical grade fabric, a sleeve of expanded PTFE (such as GOR-TEX® polytetrofluoroethelene vascular graft tubing available from W.L. Gore and Associates, Inc., Medical Products Division, 1505 N. 4th Street, Central Dock 3, Flagstaff, Ariz. 86002). Another available sleeve formed of expanded PTFE is available from IMPRA, Inc., P.O. Box 1740, Tempe, Ariz. 85280-1740.
The material may be dimensionally stable or capable of being expanded, for example, using a balloon catheter and/or one or more stents. For short lengths, vascular graft 200 (
For longer lengths, tapered vascular graft 202 (
In cases where the artery being lined is bifurcated (e.g., comprises a branch from one to two arteries), vascular graft 204 (
When strength greater than the mere material from which a vascular graft is formed becomes a consideration, the vascular graft may be reinforced, particularly when no expansion thereof is required during placement. Two typical forms of reinforcement are illustrated in
Similarly, vascular graft 208 is illustrated in
The reinforcement, e.g., rings 210 and helix 24 can be of any suitable biologically inert material such as an implantable grade of thermoplastic material, e.g., polypropylene or nylon.
Even in cases where sutures, staples, arid/or stents are used to initially hold the lining or vascular graft contiguously against the treated artery wall, utilization of tissue in-growth material at the exterior of all or part of the vascular graft may be desirable. In this regard, specific reference is made to
With reference to
Utilization of a vascular graft within the context of the present invention significantly tends to provide a barrier between the bloodstream and the vessel wall which is believed to reduce restenosis, provides a conduit through which the blood can flow which is known to be well-tolerated by the bloodstream, preserves the area available for blood flow, prevents an aneurysm, promotes rapid healing without excessive weeping or adhesion of blood at the lining site between the vascular graft and the adventitia layer, and provokes minimal scarring. Plaque, it has been determined, does not form on and adhere to the vascular graft.
In lieu of a pre-formed straight or tapered sleeve (with or without a bifurcation) the treated arterial wall, e.g., at interface 106, may be lined using a liquid coating of suitable material applied as a spray or otherwise and allowed to cure until a hollow lumen is defined within the cured coating and the treated arterial surface is concealed by the coating, or allowed to remain in place long enough to cause the artery to form a stable, hollow lumen. In this regard, reference is made to
Once the vascular graft of choice has been selected, other than an in-place coating, insertion of the vascular graft into the treated artery must be achieved. It is currently preferred to use a commercially available dilator/peel-away sheath generally designated 250 (
Next, steps are taken to insert the vascular graft through the sheath and locate the graft in the treated artery so as to be, preferably, at least co-extensive with the treated artery surface, with the guide wire inside the graft. The treated artery surface shown in
With the graft 270 correctly positioned in the artery 52, the forceps 260 and graft 270 are held in a stationary position, the forceps grasping the graft, as the sheath is withdrawn. In the case of peel-away sheath 256, as the sheath is withdrawn it is manually split into two pieces, as illustrated in
At this point, the forceps 260 and the graft 270, with the guide wire 62 passing centrally through the graft, are left in position and the sheath 256 has been entirely removed. Thereafter, the guide wire and graft 270 are held stationary, the mandrel control 262 manipulated to open the tips 266 causing the distal end 268 of the graft 270 to be released, following which the forceps 260 are withdrawn while the guide wire 62 and the graft 270 are retained in position as illustrated in
Alternatively, the sheath may be placed correctly in the artery 52 using a hollow mandrel, generally designated 280 (
Similarly, with or without a dilator/sheath, used in the manner described above, an elongated, long-nose forceps 290 (
Independent of the procedure used, the vascular graft 270 is now correctly located in the artery 52, with the guide wire 62 passing though the center of the vascular graft 270, as illustrated in
Insertion of a tubular graft of choice into the treated artery often involves folding or other forms of reduction in the diametral size occupied by the vascular graft during insertion, for example, to accommodate a size which will allow displacement through the sheath 256. The sheath handle may accept a graft folded shown in
By sequentially expanding, deflating, slightly displacing and once more inflating, etc., the balloon 302, the vascular graft 270 is caused to become contiguous with and adhered to the adjacent arterial wall surface, following which the balloon 302 is deflated and the balloon catheter 300 retracted along the guide wire and discarded, leaving the vascular graft 270 postured as illustrated in
Thereafter, the guide wire 62 is fully retracted, leaving the tubular vascular graft 270 positioned as essentially illustrated in
As best illustrated in
Over the longer term, the graft will be held open and contiguous with the remaining original wall of the artery throughout its length by arterial blood pressure and, in grafts so constructed, by tissue in-growth into the tissue in-growth material. This particular feature of intra-luminal graft placement solves a specific problem of by-pass graft placement where by-pass grafts have previously been placed in tissue tunnels constructed to by-pass the original duct or vessel lumen. Many such grafts are placed in body regions where, under normal activities, the body tends to compress grafts and thereby cut off flow though such grafts when they are placed in tissue tunnels which by-pass the original lumen. The example of the human knee joint is illustrated in
An improved result is obtained using the intra-luminal graft placement described herein is illustrated in
While it is currently preferred that the distal end 268 of the vascular graft 270 be without manmade connection to the vascular wall, it desired the distal end 268 may be so secured. Specifically,
Similarly, one or both ends of the vascular graft 270 may be secured to the arterial wall 104 using medical grade staples 306, as illustrated in
Furthermore, either or both ends of the vascular graft 270 can be expanded and held in contiguous relationship with arterial surface 106 using one or more stents 226, as explained above and as illustrated in
While ordinarily not necessary, the distal end 268 of the vascular graft 270 may be grasped using suitable forceps 310 for both positioning the vascular graft 270 and for holding it in position while, for example, the proximal end of the graft is suitably fastened to the arterial wall as explained above. See
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
This application is a division of our copending U.S. patent application Ser. No. 09/938,882, which is a continuation of our copending U.S. patent application Ser. No. 09/522,461 filed Mar. 9, 2000, now abandoned, which is a continuation of U.S. patent application Ser. No. 09/183,896, filed Oct. 30, 1998, now U.S. Pat. No. 6,090,135, which is a division of U.S. patent application Ser. No. 09/098,912, filed Mar. 5, 1998, now U.S. Pat. No. 5,904,146, which is a division of U.S. patent application Ser. No. 08/548,569, filed Oct. 26, 1995, now U.S. Pat. No. 5,865,844, which is a continuation of U.S. patent application Ser. No. 08/73,002, filed Jun. 7, 1993, now U.S. Pat. No. 5,571,169.
Number | Date | Country | |
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Parent | 09938882 | Aug 2001 | US |
Child | 11247571 | Oct 2005 | US |
Parent | 09098912 | Mar 1998 | US |
Child | 09183896 | Oct 1998 | US |
Parent | 08548569 | Oct 1995 | US |
Child | 09098912 | Mar 1998 | US |
Number | Date | Country | |
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Parent | 09522461 | Mar 2000 | US |
Child | 09938882 | Aug 2001 | US |
Parent | 09183896 | Oct 1998 | US |
Child | 09522461 | Mar 2000 | US |
Parent | 08073002 | Jun 1993 | US |
Child | 08548569 | Oct 1995 | US |