Intravascular cuff

This application relates to US Provisional Patent Application No. 60 / 685,433 filed May 27, 2005, entitled "Intravascular Cuff" by Wilson et al., Claiming the interests of these priorities. Incorporated herein as a reference. The application is also filed with the US Patent Application No. entitled "Stentless Support Structure" filed by the Applicant on the same day as the Application and the May 27, 2005 application entitled "Stentless Support Structure". US Provisional Patent Application No. 60 / 685,349 and US Provisional Patent Application No. 60 / 709,595, filed August 15, 2005, entitled "Stentless Support Structure" are incorporated with reference.

There is a striking move towards developing and performing cardiac and other surgeries that use a percutaneous approach. For example, through the use of one or more catheters introduced through the femoral artery, tools and devices can be delivered to the desired area in the cardiovascular system, otherwise usually invasive surgical procedures. Many complex procedures are performed that require. Such an approach can greatly reduce the trauma that the patient tolerates and significantly reduce the recovery period. The percutaneous approach is a very attractive alternative to performing thoracotomy.

Valve replacement surgery provides an example of areas where percutaneous solutions are being developed. Numerous diseases result in thickening of the leaflets of the petals, followed by immobility or diminished movement. Immobility of the valve results in narrowing or stenosis of the passage through the valve. The increased resistance to blood flow provided by the narrowed valve eventually leads to heart failure and ultimately death.

Treatment of valve stenosis or regurgitation has previously included complete removal of the existing native valve, followed by prosthetic valve transplantation. Naturally, this is a very invasive procedure that causes very large trauma to the body and usually results in very discomfort and a very long recovery period. Treating valve stenosis or regurgitation is also a very complex procedure that requires great skill and talent to perform.

Historically, such valve replacement surgery has been performed using traditional thoracotomy, in which the chest is opened, the heart is stopped, the patient is placed with a cardiopulmonary bypass, and by nature. The valve is removed and a replacement valve is installed. An alternative method of percutaneous valve replacement proposed is disclosed in Patent Document 1 published by Anderson et al. (Incorporated herein by reference in its entirety). In this patent, the prosthetic valve is crushed to a size that fits inside the catheter. A catheter is then inserted into the patient's vascular structure and moved to place the collapsed valve in place of the native valve. The deployment mechanism is activated to extend the replacement valve against the wall of the body's lumen. The diastolic force presses against the foliage of the native valve that is present against the wall of the lumen and virtually "extracts" the native valve for any intent and purpose. The extended structure, including the stent, which is configured to have the shape of a valve with foliate support of the valve, is then released from the catheter and begins to function as a native valve. As a result, complete valve replacement is achieved, but significantly reduces the physical impact on the patient.

However, this approach has decisive drawbacks. One particular drawback of the percutaneous approach disclosed in Anderson's Patent Document 1 is that it is difficult to prevent leakage around the new valve after implantation. Since the tissue of the natural valve remains in the lumen, the connection junction and fusion point of the valve tissue (when pressed against the lumen wall) seals around the interface between the lumen and the prosthetic valve. May be strong to make it difficult.

Another drawback of Anderson's Patent Document 1 approach concerns the reliability of the stent as a support scaffold for the prosthetic valve. First, it can form an embolus as the stent expands. Second, stents are generally ineffective in capturing the embolus removed by the stent, either during or after deployment. Third, the stent generally does not fit the nature of the natural lumen in which the stent is placed, causing the prosthetic valve contained within the stent to suffer a valve side leak. Fourth, the stent can be difficult to center in the lumen.

With respect to the first drawback, stents usually fall into one of two categories: self-expanding stents and expandable stents. The self-expanding stent is compressed when loaded into the catheter and expanded to its original uncompressed size when released from the catheter. The balloon expandable stent is loaded into the catheter in a compressed but loose state. The balloon is placed inside the stent. During deployment, the catheter is pulled out and the balloon is inflated, thereby expanding the stent to the desired size. Both of these stents show considerable force during expansion. This force is usually sufficient to crush and break the thrombus, thereby removing and embolizing multiple atherosclerotic plaques. Some degree of such dilation is desirable if the stent has been implanted to treat a narrowed vessel. However, if the stent is implanted solely to remove the native valve, less force may be desirable to reduce the chance of forming an embolus.

With respect to the second drawback, when an embolus is formed, the expanded stent usually has members that are too spaced to be effective in capturing any material that is removed. In many cases, second precautions must be taken, including the use of nets and wash ports.

The third drawback is due to the relative inflexibility of the stent. The stent relies on the elastic properties of the innate vasculature that fits around the stent. The stent used to open a narrow vessel does not require a seal between the vessel and the stent. However, when removing the native valve and using the stent to accommodate the prosthetic valve, a seal between the stent and the vessel is required to prevent leakage near the valve. The incompatible nature of the stent makes this seal difficult to achieve, especially when removing the foliage of the narrowed valve.

The fourth drawback is that the stent can be difficult to center in the lumen. The narrowed valve can have a very irregular shape. When placing a stent in an irregularly shaped calcified valve, the delivery catheter can be misaligned, causing the stent to be off-center, such as between the lobules of two calcified valves. Is delivered. Expanding the stent in such a position can result in a poor pedestal to the luminal wall, and significant valve side leakage, or a non-functional prosthetic valve.<patcit num="1"><text>U.S. Pat. No. 6,168,614</text></patcit>

<p> The present invention addresses the above drawbacks by providing a tubular or donut-shaped cuff that surrounds the innate valve and creates an ideal implantation site for the stent. The cuff is composed of a material with superelastic or shape memory properties, eg, at least one fine woven strand of nitinol. The cuff is tubular when in an extended configuration within the delivery catheter. When released from the delivery catheter, the end of the cuff curls over itself, trapping the foliar part of the native valve between the curled ends. The center of the cuff does not extend to the edges, thereby making it an ideal reduced diameter lumen for receiving intravascular devices.</p>

Here, with reference to the drawings and first with reference to FIGS. 1 and 2, the intravascular cuff 10 of the present invention is shown. The cuff 10 is shown in a relaxed and extended configuration and has a generally tubular structure with two flared ends 12 and 13 and a narrow tubular body 14. The elongated tube used to build the cuff 10 is formed from at least one woven strand that is capable of exhibiting superelasticity or shape memory. In one embodiment, the elongated tube is folded in half over itself so that the first end 12 becomes the folded end and the second end 13 contains a plurality of unwoven strands. Therefore, the tubular body has two layers. The strand or multiple strands can be fibrous, non-fibrous, polyfiber, or even filaments. Nitinol is an example of a preferred material for strands. Strands are woven to allow the device to expand longitudinally within a very long, thin tube that can be placed in a very small delivery catheter. Preferably, the cuff 10 can be inserted into a delivery catheter with a size of 16 Fr or less. The braid is tight enough to catch the embolus that can be removed from the wall of the lumen, yet allows for a thin elongated construction.

The cuff 10 includes a central canal 16 extending through the entire cuff 10. The central canal 16 is sized to receive a delivery catheter for a prosthetic device such as a stent. Preferably, the lumen 16 has a slightly flared or mushroom-like end, thereby creating a funnel to guide the delivery catheter to the center of the lumen 16.

Figures 1 and 2 show that the lumen 16 is small and very clearly demarcated, even when the cuff 10 is in a radially dilated and relaxed configuration. Thus, when deployed, the cuff lumen 16 is clearly demarcated, the mushroom-shaped ends 12 and 13 dilate and the target vasculature remains relatively centrally located within the cuff 10. Fits the shape of. Therefore, the cuff 10 provides an ideal target and guide for the physician to place a prosthetic valve or stent within the cuff. Preferably, the cuff 10 is radiation permeable, making the target even more accessible.

The deployment of cuff 10 is illustrated in Figures 3-7. Starting from FIG. 3, the cuff 10 is percutaneously delivered to the target narrowed valve 18 via the delivery catheter 20. The catheter 20 is advanced until the distal end 22 of the catheter passes through the target valve 18.

The delivery catheter 20 is then retracted against the cuff 10 as seen in FIG. Doing so releases the distal end 12, which immediately flares outward. Since there is an end 12 that contacts the vascular wall, the physician can gently pull on the catheter 20 and the cuff 10 so that the end 12 of the cuff 10 contacts the narrowed valve 18 and thus the appropriate cuff 10. Ensure placement.

The catheter 20 is then fully retracted, allowing the proximal end 13 of the cuff 10 to extend relative to the vascular wall on the proximal side of the narrowed valve 18, as shown in FIG. To. Here, the narrowed valve 18 is completely covered by the braided mesh of the cuff 10, and the cuff is ready to receive a prosthetic device such as the stented prosthetic valve 24 (FIGS. 6 and 7). .. In particular, despite the irregular shape of the narrowed valve 18, the central canal 16 of the cuff provides a path through the target site and provides an ideal receiving pedestal for the prosthetic valve 24.

In FIG. 6, the stented prosthetic valve 26 is percutaneously delivered to the cuff 10 via the catheter 28. The catheter 28 is inserted directly into the cuff lumen 16 using the funnel-shaped end 13 as a guide.

In FIG. 7, the prosthetic valve 26 is dilated and the catheter 28 is removed. Dilating the stented prosthetic valve 26 always dilates the central canal 16. Doing so shortens the cuff 10, further folds the flared ends 12 and 13 and provides a stronger grip with the narrowed valve 18. In addition, any plaque or other material removed during the expansion of the prosthetic valve 26 is captured by the ends 12 and 13. The cuff 10 provides an optimal pedestal for the prosthetic valve 26 and prevents any blood from leaking around the prosthetic valve 26. Over time, the woven strands promote inward growth, further improving the seal provided by the cuff 10.

One embodiment of the invention uses an unwoven fabric to further enhance the seal created between the cuff 10 and the vascular wall. FIG. 8 shows a cuff 10 with a two-layer body, with material 32 trapped between the two layers. The unwoven fabric expands easily so that the expansion characteristics of the cuff 10 are not affected. In addition, material 32 can be impregnated with therapeutic compounds. Material 32 can consist of unwoven material, woven fabric, polymer or other material.

With reference to FIGS. 9 and 10, the cuff 10 first drawn in FIGS. 1 and 2 is shown with a plug 30 that dilates the central canal 16 of the cuff 10. This shows that when the lumen 16 is dilated, the cuff 10 is shortened and the ends 12 and 13 are folded back. The dilation of the central canal 16 then causes the ends 12 and 13 to create a strong grip on the innate tissue, such as the foliage of the valve, housed between the ends 12 and 13.

In another embodiment, upon deployment from the catheter, the end of the elongated tube wraps outward toward the center of the device. Alternatively, the edges can be rolled inward towards the center of the device. This movement is facilitated by the use of hyperelastic or shape memory materials such as nitinol.

Although the present invention has been described from the point of view of a particular embodiment or application, those skilled in the art, in view of the present teaching, do not deviate from the claimed spirit of the present invention or the scope of the claimed invention. Further embodiments and modifications can be produced without exceeding. Therefore, it is understood that the drawings and descriptions herein are provided by way of illustration to facilitate understanding of the invention and should not be understood to limit the scope of the invention.

<figref num="1">FIG. 1 is a side view of a suitable device of the present invention.</figref><figref num="2">FIG. 2 is an end view of the device of FIG.</figref><figref num="3">FIG. 3 is a cut-out view of the device of the invention deployed in a native vessel.</figref><figref num="4">FIG. 4 is a cut-out view of the device of the invention deployed in a native vessel.</figref><figref num="5">FIG. 5 is a cut-out view of the device of the invention deployed in a native vessel.</figref><figref num="6">FIG. 6 is a cut-out view of the device of the invention deployed in a native vessel.</figref><figref num="7">FIG. 7 is a cut-out view of the device of the invention deployed in a native vessel.</figref><figref num="8">FIG. 8 is a side view of a suitable device of the present invention.</figref><figref num="9">FIG. 9 is an end view of the device of FIG. 1 in the expanded state.</figref><figref num="10">FIG. 10 is a side view of the device of FIG. 1 in the expanded state.</figref>