Patent Description:
Complications of the mitral valve, which controls the flow of blood from the left atrium into the left ventricle of the human heart, have been known to cause fatal heart failure. In the developed world, one of the most common forms of valvular heart disease is mitral valve leak, also known as mitral regurgitation, which is characterized by the abnormal leaking of blood from the left ventricle through the mitral valve and back into the left atrium. This occurs most commonly due to ischemic heart disease when the leaflets of the mitral valve no longer meet or close properly after multiple infarctions, idiopathic and hypertensive cardiomyopathies where the left ventricle enlarges, and with leaflet and chordal abnormalities, such as those caused by a degenerative disease.

In addition to mitral regurgitation, mitral narrowing or stenosis is most frequently the result of rheumatic disease. While this has been virtually eliminated in developed countries, it is still common where living standards are not as high.

Similar to complications of the mitral valve are complications of the aortic valve, which controls the flow of blood from the left ventricle into the aorta. For example, many older patients develop aortic valve stenosis. Historically, the traditional treatment had been valve replacement by a large open heart procedure. The procedure takes a considerable amount of time for recovery since it is so highly invasive. Fortunately, in the last decade, great advances have been made in replacing this open heart surgery procedure with a catheter procedure that can be performed quickly without surgical incisions or the need for a heart-lung machine to support the circulation while the heart is stopped. Using catheters, valves are mounted on stents or stent-like structures, which are compressed and delivered through blood vessels to the heart. The stents are then expanded and the valves begin to function. The diseased valve is not removed, but instead it is crushed or deformed by the stent which contains the new valve. The deformed tissue serves to help anchor the new prosthetic valve.

Delivery of the valves can be accomplished from arteries which can be easily accessed in a patient. Most commonly this is done from the groin where the femoral and iliac arteries can be cannulated. The shoulder region is also used, where the subclavian and axillary arteries can also be accessed. Recovery from this procedure is remarkably quick.

Not all patients can be served with a pure catheter procedure. In some cases the arteries are too small to allow passage of catheters to the heart, or the arteries are too diseased or tortuous. In these cases, surgeons can make a small chest incision (thoractomy) and then place these catheter-based devices directly into the heart. Typically, a purse string suture is made in the apex of the left ventricle and the delivery system is placed through the apex of the heart. The valve is then delivered into its final position. These delivery systems can also be used to access the aortic valve from the aorta itself. Some surgeons introduce the aortic valve delivery system directly in the aorta at the time of open surgery. The valves vary considerably. There is a mounting structure that is often a form of stent. Prosthetic leaflets are carried inside the stent on mounting and retention structure. Typically, these leaflets are made from biologic material that is used in traditional surgical valves. The valve can be actual heart valve tissue from an animal or more often the leaflets are made from pericardial tissue from cows, pigs or horses. These leaflets are treated to reduce their immunogenicity and improve their durability. Many tissue processing techniques have been developed for this purpose. In the future, biologically engineered tissue may be used or polymers or other non-biologic materials may be used for valve leaflets.

There are, in fact, more patients with mitral valve disease than aortic valve disease. In the course of the last decade, many companies have been successful in creating catheter or minimally invasive implantable aortic valves, but implantation of a mitral valve is more difficult and to date there has been no good solution. Patients would be benefited by implanting a device by a surgical procedure employing a small incision or by a catheter implantation such as from the groin. From the patient's point of view, the catheter procedure is very attractive. At this time there is no commercially available way to replace the mitral valve with a catheter procedure. Many patients who require mitral valve replacement are elderly and an open heart procedure is painful, risky and takes time for recovery. Some patients are not even candidates for surgery due to advanced age and frailty. Therefore, there exists a particular need for a remotely placed mitral valve replacement device.

While previously, it was thought that mitral valve replacement rather than valve repair was associated with a more negative long-term prognosis for patients with mitral valve disease, this belief has come into question. It is now believed that the outcome for patients with mitral valve leak or regurgitation is almost equal whether the valve is repaired or replaced. Furthermore, the durability of a mitral valve surgical repair is now under question. Many patients, who have undergone repair, redevelop a leak over several years. As many of these are elderly, a repeat intervention in an older patient is not welcomed by the patient or the physicians.

The most prominent obstacle for catheter mitral valve replacement is retaining the valve in position. The mitral valve is subject to a large cyclic load. The pressure in the left ventricle is close to zero before contraction and then rises to the systolic pressure (or higher if there is aortic stenosis) and this can be very high if the patient has systolic hypertension. Often the load on the valve is 150mmHg or more. Since the heart is moving as it beats, the movement and the load can combine to dislodge a valve. Also, the movement and rhythmic load can fatigue materials leading to fractures of the materials. Thus, there is a major problem associated with anchoring a valve.

Another problem with creating a catheter delivered mitral valve replacement is size. The implant must have strong retention and leak avoidance features and it must contain a valve. Separate prostheses may contribute to solving this problem, by placing an anchor or dock first and then implanting the valve second. However, in this situation, the patient must remain stable between implantation of the anchor or dock and implantation of the valve. If the patient's native mitral valve is rendered non-functional by the anchor or dock, then the patient may quickly become unstable and the operator may be forced to hastily implant the new valve or possibly stabilize the patient by removing the anchor or dock and abandoning the procedure.

Another problem with mitral replacement is leak around the valve, or paravalvular leak. If a good seal is not established around the valve, blood can leak back into the left atrium. This places extra load on the heart and can damage the blood as it travels in jets through sites of leaks. Hemolysis or breakdown of red blood cells is a frequent complication if this occurs. Paravalvular leak was one of the common problems encountered when the aortic valve was first implanted on a catheter. During surgical replacement, a surgeon has a major advantage when replacing the valve as he or she can see a gap outside the valve suture line and prevent or repair it. With catheter insertion, this is not possible. Furthermore, large leaks may reduce a patient's survival and may cause symptoms that restrict mobility and make the patient uncomfortable (e.g., short of breathe, edematous, fatigued). Therefore, devices, systems, and methods which relate to mitral valve replacement should also incorporate means to prevent and repair leaks around the replacement valve.

A patient's mitral valve annulus can also be quite large. When companies develop surgical replacement valves, this problem is solved by restricting the number of sizes of the actual valve produced and then adding more fabric cuff around the margin of the valve to increase the valve size. For example, a patient may have a <NUM> valve annulus. In this case, the actual prosthetic valve diameter may be <NUM> and the difference is made up by adding a larger band of fabric cuff material around the prosthetic valve. However, in catheter procedures, adding more material to a prosthetic valve is problematic since the material must be condensed and retained by small delivery systems. Often, this method is very difficult and impractical, so alternative solutions are necessary.

Since numerous valves have been developed for the aortic position, it is desirable to avoid repeating valve development and to take advantage of existing valves. These valves have been very expensive to develop and bring to market, so extending their application can save considerable amounts of time and money. It would be useful then to create a mitral anchor or docking station for such a valve. An existing valve developed for the aortic position, perhaps with some modification, could then be implanted in the docking station. Some previously developed valves may fit well with no modification, such as the Edwards Sapien™ valve. Others, such as the Corevalve™ may be implantable but require some modification for an optimal engagement with the anchor and fit inside the heart.

A number of further complications may arise from a poorly retained or poorly positioned mitral valve replacement prosthesis. Namely, a valve can be dislodged into the atrium or ventricle, which could be fatal for a patient. Prior prosthetic anchors have reduced the risk of dislodgement by puncturing tissue to retain the prosthesis. However, this is a risky maneuver since the penetration must be accomplished by a sharp object at a long distance, leading to a risk of perforation of the heart and patient injury.

Orientation of the mitral prosthesis is also important. The valve must allow blood to flow easily from the atrium to the ventricle. A prosthesis that enters at an angle may lead to poor flow, obstruction of the flow by the wall of the heart or a leaflet and a poor hemodynamic result. Repeated contraction against the ventricular wall can also lead to rupture of the back wall of the heart and sudden death of the patient.

With surgical mitral valve repair or replacement, sometimes the anterior leaflet of the mitral valve leaflet is pushed into the area of the left ventricular outflow and this leads to poor left ventricular emptying. This syndrome is known as left ventricular tract outflow obstruction. The replacement valve itself can cause left ventricular outflow tract obstruction if it is situated close to the aortic valve.

Yet another obstacle faced when implanting a replacement mitral valve is the need for the patient's native mitral valve to continue to function regularly during placement of the prosthesis so that the patient can remain stable without the need for a heart-lung machine to support circulation.

In addition, it is desirable to provide devices and methods that can be utilized in a variety of implantation approaches. Depending on a particular patient's anatomy and clinical situation, a medical professional may wish to make a determination regarding the optimal method of implantation, such as inserting a replacement valve directly into the heart in an open procedure (open heart surgery or a minimally invasive surgery) or inserting a replacement valve from veins and via arteries in a closed procedure (such as a catheter-based implantation). It is preferable to allow a medical professional a plurality of implantation options to choose from. For example, a medical professional may wish to insert a replacement valve either from the ventricle or from the atrial side of the mitral valve.

Therefore, the present disclosure provides devices and methods that address these and other challenges in the art. <CIT> and <CIT> disclose systems for replacing a native heart valve, comprising an expansible helical anchor and an expansible heart valve prosthesis. <CIT> discloses an expansible heart valve prosthesis.

The invention provides a system for replacing a native heart valve including an expansible helical anchor formed as multiple coils adapted to support a heart valve prosthesis. At least one of the coils is normally at a first diameter, and is expandable to a second, larger diameter upon application of radial outward force from within the helical anchor. A gap may be defined between adjacent coils sufficient to prevent engagement by at least one of the adjacent coils with the native heart valve. An expansible heart valve prosthesis is provided and is configured to be delivered into the helical anchor and expanded inside the multiple coils into engagement with the at least one coil. This moves at least that coil from the first diameter to the second diameter while securing the helical anchor and the heart valve prosthesis together. The system further includes a seal on the expansible heart valve prosthesis configured to engage the helical anchor and prevent blood leakage past the heart valve prosthesis after implantation of the heart valve prosthesis in the helical anchor.

The system may include one or more additional aspects. For example, the helical anchor may include another coil that moves from a larger diameter to a smaller diameter as the heart valve prosthesis is expanded inside the multiple coils. The seal may take many alternative forms. For example, the seal can include portions extending between adjacent coils for preventing blood leakage through the helical anchor and past the heart valve prosthesis. The seal may be comprised of many different alternative materials. The seal may further comprise a membrane or panel extending between at least two coils of the helical anchor after implantation of the heart valve prosthesis in the helical anchor. For example, one example is a biologic material. The helical anchor may further comprise a shape memory material. The heart valve prosthesis includes a blood inflow end and a blood outflow end and at least one of the ends may be unflared and generally cylindrical in shape. In an illustrative embodiment, the blood outflow end is flared radially outward and includes a bumper for preventing damage to tissue structure in the heart after implantation. The gap may be formed by a coil portion of the helical anchor that extends non-parallel to adjacent coil portions of the helical anchor.

In an example, a system is provided as generally described above, except that the seal is alternatively or additionally carried on the helical anchor instead of being carried on the heart valve prosthesis. Any other features as described or incorporated herein may be included.

In another example, a system for docking a heart valve prosthesis includes a helical anchor formed as multiple coils adapted to support a heart valve prosthesis with coil portions positioned above and/or below the heart valve annulus. An outer, flexible and helical tube carries the coils of the helical anchor to form an assembly. A helical delivery tool carries the assembly and is adapted to be rotated into position through a native heart valve. Additional or optional features may be provided. For example, a heart valve prosthesis may be expanded inside the multiple coils. The outer tube may be formed from a low friction material adapted to slide off of the multiple coils of the helical anchor after rotating into position through the native heart valve. The outer tube may be secured to the helical delivery tool with suture or by any other method. The helical delivery tool may formed with a plurality of coils, and the outer tube may further be secured to the distal end. The distal end may further comprise a bullet or tapered shape to assist with delivery. The distal end can further comprise a resilient element, and the distal ends of the outer tube and the helical delivery tube are secured to the resilient element.

In another example, a system for replacing a native heart valve includes a helical anchor formed as multiple coils adapted to support a heart valve prosthesis at the native heart valve. An expansible heart valve prosthesis is provided in this system and is capable of being delivered into the helical anchor and expanded inside the multiple coils into engagement with the at least one coil to secure the helical anchor and the heart valve prosthesis together. A guide structure on the expansible heart valve prosthesis is configured to guide the helical anchor into position as the helical anchor is extruded from a helical anchor delivery catheter.

The guide structure may further comprise an opening within a portion of the expansible heart valve prosthesis, such as an opening in a loop, a tube or simply an opening in the stent structure of the expansible heart valve prosthesis, for example. The opening may be configured to receive a helical anchor delivery catheter that carries the helical anchor during the implantation procedure. The opening may be located on an arm of the expansible heart valve prosthesis and the prosthesis may further comprise a plurality of arms configured to engage beneath the native heart valve. The guide structure may further comprise a tubular arm of the expansible heart valve prosthesis.

In another example, a system for docking a mitral valve prosthesis and replacing a native mitral valve is provided and includes a coil guide catheter and a helical anchor adapted to be received in and delivered from the coil guide catheter. The helical anchor is formed as multiple coils having a coiled configuration after being delivered from the coil guide catheter and adapted to support the mitral valve prosthesis upon being fully delivered from the coil guide catheter and implanted at the native mitral valve. The system further includes a tissue gathering catheter including loop structure configured to be deployed to surround and gather the native chordea tendinae for allowing easier direction of the helical anchor in the left ventricle.

In another example, an anchor for docking a heart valve prosthesis includes an upper helical coil portion, a lower helical coil portion, and a fastener securing the upper helical coil portion to the lower helical coil portion.

In another example, a method (not forming part of the invention) of implanting a heart valve prosthesis in the heart of a patient includes holding a helical anchor in the form of multiple coils within an outer, flexible tube. The assembly of the outer, flexible tube and the helical anchor is secured to a helical delivery tool. The helical delivery tool is rotated adjacent to a native heart valve of the patient to position the assembly on either or both sides of the native heart valve. The assembly is removed from the helical delivery tool, and the outer tube is removed from the helical anchor. The heart valve prosthesis is then implanted within the helical anchor.

Securing the assembly may further comprise positioning coils of the assembly generally along adjacent coils of the helical delivery tool. Removing the outer tube may further comprise holding the helical anchor with a pusher element, and pulling the outer tube off the helical anchor.

In another example, a method (not forming part of the invention) of implanting an expansible heart valve prosthesis in the heart of a patient includes delivering an expansible helical anchor in the form of multiple coils proximate the native heart valve. The expansible heart valve prosthesis is positioned within the multiple coils of the expansible helical anchor with the expansible heart valve prosthesis and the expansible helical anchor in unexpanded states. The expansible heart valve prosthesis is expanded against the expansible helical anchor thereby expanding the expansible heart valve prosthesis while securing the expansible heart valve prosthesis to the expansible helical anchor. A seal is carried on the helical anchor and/or on the heart valve prosthesis and extends between at least two adjacent coils for preventing blood leakage through the helical anchor and past the heart valve prosthesis.

In another example, a method (not forming part of the invention) of implanting an expansible heart valve prosthesis to replace a native heart valve of a patient includes delivering a helical anchor in the form of multiple coils proximate the native heart valve. The expansible heart valve prosthesis is delivered proximate the native heart valve. The helical anchor is guided generally around a periphery of the expansible heart valve prosthesis using guide structure carried on the expansible heart valve prosthesis. The expansible heart valve prosthesis is expanded against the helical anchor. As discussed above, the guide structure may take many different forms.

In another example, a method (not forming part of the invention) of implanting a helical anchor for docking a mitral heart valve prosthesis in a patient includes gathering the chordea tendinae using a tissue gathering catheter. A helical anchor is then delivered in the form of multiple coils proximate a native heart valve and around the gathered chordae tendinae.

In another example, a method (not forming part of the invention) of implanting a helical anchor for docking a heart valve prosthesis in a patient includes delivering an upper helical anchor portion comprised of upper coils to a position above a native heart valve, and delivering a lower helical anchor portion comprised of lower coils to a position below the native heart valve. The upper and lower helical anchor portions are secured together with a fastener either before or after delivery of each helical anchor portion.

In another example, a system for replacing a native heart valve is provided and includes an expansible helical anchor formed as multiple coils adapted to support a heart valve prosthesis. At least one of the coils is normally at a first diameter, and is expandable to a second, larger diameter upon application of radial outward force from within the helical anchor. A gap is defined between adjacent coils sufficient to prevent engagement by at least one of the adjacent coils with the native heart valve. An expansible heart valve prosthesis is provided and is capable of being delivered into the helical anchor and expanded inside the multiple coils into engagement with the at least one coil. In this manner, the expansible coil moves from the first diameter to the second diameter while securing the helical anchor and the heart valve prosthesis together. The expansible heart valve prosthesis includes an inflow end and an outflow end. The inflow end is unflared and generally cylindrical, while the outflow end is flared in a radially outward direction.

Various additional advantages, methods, devices, systems and features will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings.

It will be appreciated that like reference numerals throughout this description and the drawings refer generally to like elements of structure and function. The differences between embodiments and examples will be apparent from the drawings and/or from the description and/or the use of different reference numerals in different figures. For clarity and conciseness, description of like elements will not be repeated throughout the description. Only the embodiments of <FIG> disclose systems according to the invention comprising an expansible heart valve including a bumper.

Referring first to <FIG> in conjunction with <FIG>, as previously discussed in Applicant's PCT Application Serial No. <CIT>, a deflectable catheter <NUM> makes implantation of a helical anchor <NUM> much easier. The deflectable tip 10a of the catheter <NUM> assists with the helical anchor <NUM> engaging a commissure <NUM> of the native mitral valve <NUM>, as shown in <FIG>. The tip 10a of the catheter <NUM> may be designed and configured such that it can bend downward toward the native leaflets <NUM>, <NUM> of the mitral valve <NUM>. Once the tip 10a of the catheter <NUM> is placed generally over the commissure <NUM> as shown in <FIG>, the tip or distal end 10a may be bent downward and it is then relatively easy to push or extrude the helical anchor <NUM> out of the distal end 10a and downward through the mitral valve <NUM> as shown in <FIG>.

Now referring to <FIG>, <FIG>, the deflectable catheter, or anchor delivery catheter <NUM>, may be deflectable at many different points or locations. Deflecting the catheter tip 10a outward to increase the radius of the delivery catheter tip 10a can be very helpful, as shown in <FIG> which show the "before" and "after" effects of deflecting the distal end 10a. Deflecting the catheter <NUM> in this way will give the helical anchor <NUM> a larger diameter starting turn or coil <NUM>. As an example, this turn or coil <NUM> of the helical anchor <NUM> may normally be <NUM> but operating the distal end 10a of the catheter <NUM> in this manner can enlarge the diameter to <NUM>. Opening up the first turn or coil <NUM> of the helical anchor <NUM> in this way would help the helical anchor <NUM> capture all chordae <NUM> and leaflets <NUM>, <NUM> as the helical anchor <NUM> is introduced as generally discussed above in connection with <FIG> and <FIG>. As the helical anchor <NUM> advances, the distal end 10a of the delivery catheter <NUM> could also deflect inward to help the helical anchor <NUM> capture all of the chordae <NUM> at the opposite commissure. Moving the distal end 10a of the delivery catheter <NUM> from side to side as the helical anchor <NUM> is essentially screwed or rotated into and through the native mitral valve <NUM> is essentially like tracking the delivery catheter <NUM> with the turn or coil <NUM>. In this case, however, the delivery catheter <NUM> is stationary as only the tip 10a is moving with the coils <NUM>. Deflectability of the distal end 10a in any direction may be achieved by embedding a wire <NUM> that runs the length of the delivery catheter <NUM>. When the wire <NUM> is pulled, the delivery catheter tip 10a deflects and deforms into various shapes as desired or needed in the procedure.

A procedure will now be described for introducing or implanting a helical anchor <NUM> in connection with <FIG>, <FIG>, and <FIG>. A helical delivery tool <NUM> including coils <NUM> is used to deliver the helical anchor <NUM> which is contained within an outer tube <NUM>, for example, formed from a Goretex or other low friction material, such as PTFE. Suture <NUM> is used to secure the combination or assembly of the outer tube <NUM> and helical anchor <NUM> in place on the coils <NUM> of the helical delivery tool <NUM>. A groove (not shown) may be formed in the helical tool <NUM> so that it provides a secure seat for the suture. Additional suture <NUM> is used to tie the leading end of the outer tube <NUM> through a loop <NUM> at the end of the helical delivery tool <NUM>. The helical delivery tool <NUM> and outer tube/helical anchor combination <NUM>, <NUM> is turned into the heart <NUM>, through the mitral valve <NUM> as shown and the suture <NUM> is cut, for example, with a scalpel <NUM> (<FIG>). A pair of forceps <NUM> is used to turn the tool <NUM> in through the native mitral valve <NUM> slightly more and this breaks the suture <NUM> (<FIG>). The helical tool <NUM> is then rotated in an opposite direction and removed from the heart <NUM>, leaving the helical anchor <NUM> combined with the outer tube <NUM> in the heart <NUM>, as shown. A push rod <NUM> with a cupped end <NUM> is inserted into the trailing end of the outer tube <NUM> (<FIG>). The outer tube <NUM> is then pulled backwards or rearward leaving the helical anchor <NUM> in place while removing the outer tube <NUM>. Due to the low friction material of the outer tube <NUM>, it easily slides off of the helical anchor <NUM>. <FIG>, respectively, show full implantation of the helical anchor <NUM> and a replacement heart valve <NUM> mounted within and firmly against the helical anchor <NUM>. The replacement valve <NUM> includes leaflets <NUM>, <NUM>, and a body <NUM> which may be of any suitable design, such as an expandable stent design.

<FIG> show a bullet shaped head <NUM> provided on the helical tool <NUM>. There is a slit <NUM> on the bullet-shaped head <NUM> that runs parallel to the helical shaped wire or coil <NUM> adjacent to the head <NUM>. The bullet-shaped head <NUM> is formed from resilient, polymer, for example, and the slit <NUM> opens and closes by way of this resiliency. Again, the outer tube <NUM> is fixed to the helical delivery tool <NUM> with a suture (not shown). The leading end 32a of the outer tube <NUM> is inserted into the bullet-shaped head <NUM>, for example, with forceps <NUM>. Here, the bullet-shaped head <NUM> provides for easier insertion due to its tapered shape.

<FIG> show the combination of a delivery catheter <NUM> with a helical anchor <NUM> inside, before deployment. The distal tip 10a of the delivery catheter <NUM> includes a taper which may be gradually tapered as shown in <FIG>, or more rounded as shown in <FIG>. In each case, the distal tip 10a configuration allows for smoother, easier delivery to a native mitral valve location and can maneuver through tissue structure, such as native tissue, within the heart <NUM>. For example, the distal end 10a of the delivery catheter <NUM> may be directed through the mitral valve <NUM> and may need to encircle the chordae <NUM> either partially or fully (<FIG>). As shown in <FIG>, the helical anchor <NUM> may be constructed with an internal wire coil 12a and an external covering or coating 12b such as fabric, and may include a soft tip 12c, such as formed from polymer, to avoid damage to heart tissue during delivery and to enable easier delivery.

<FIG> is a cross-sectional view showing an illustrative stent mounted replacement heart valve or prosthesis <NUM> at the native mitral valve <NUM> location docked in a helical anchor <NUM>. According to the invention, a "bumper" structure <NUM> has been added to the annular edge at the outflow end of the valve <NUM>. This bumper structure <NUM> may be formed, for example, from foam <NUM> covered by a sealing material <NUM> such as fabric or another suitable material or coating. This sealing layer <NUM> extends upward over an open stent structure <NUM> of the valve <NUM> to prevent blood leakage past the valve <NUM> and through the coils <NUM> of the helical anchor <NUM>.

<FIG> is an enlarged view of a replacement heart valve <NUM> similar to the valve shown in <FIG>, but showing radially outward flared inflow and outflow ends.

<FIG> is an enlarged sectional view showing a generally cylindrical outflow end, without a radially outward flare.

<FIG> illustrate another illustrative embodiment of the invention including a helical anchor <NUM> docking or mounting a replacement stent valve <NUM> and including biological tissue seal <NUM>, such as pericardium tissue or other animal tissue used at both the location of the bumper <NUM> to cover the internal foam layer <NUM>, as well as to seal and cover the open stent structure <NUM> up to the location of an existing fabric layer <NUM> circumscribing the replacement heart valve <NUM>. The combination of the existing fabric layer <NUM> on the stent valve <NUM> and the seal layer <NUM> circumscribing the lower or outflow portion of the valve <NUM> prevents blood flow from leaking past the valve <NUM> through the stent structure <NUM>. Instead, the blood passes as it should through the leaflets <NUM>, <NUM> of the replacement valve <NUM>. As further shown in <FIG>, the helical anchor <NUM> is preferably formed of spaced apart coils <NUM> creating a gap <NUM> such as previously discussed in connection with PCT Application Serial No. <CIT> published as <CIT>, or spaced apart or formed as otherwise desired. As further described in <CIT>, the helical anchor <NUM> is expansible by the stent valve <NUM>.

Referring to <FIG>, an initial portion of a procedure is shown. In this figure, a sheath <NUM> and delivery catheter <NUM> have been advanced through a peripheral vein into the right atrium <NUM> of the heart <NUM>, across the atrial septum <NUM>, to the left atrium <NUM>. A distal end 10a of the delivery catheter <NUM> is positioned in the left ventricle <NUM> by being directed through the native mitral valve <NUM>. This delivery catheter <NUM> contains a self-expanding or stent mounted mitral prosthesis or replacement valve <NUM> that is to be implanted at the location of the native mitral valve <NUM>. A super elastic or shape memory type material, such as Nitinol, is typically used to form the frame structure or body <NUM> of the self-expanding replacement valve <NUM>, but other materials may be used instead. The frame or body <NUM> includes artificial valve leaflets <NUM>, <NUM> typically formed from tissue such as pericardial cow or pig tissue. Leaflets <NUM>, <NUM> could instead be formed of other materials, such as synthetic or other biomaterials, e.g., materials derived from small intestinal mucosa. As described further below, the delivery catheter <NUM> also contains a helical anchor <NUM> and delivery system. The helical anchor <NUM> may generally take the forms described herein or previously disclosed, for example, in PCT Application Serial Nos. <CIT> and <CIT> published as <CIT>.

<FIG> illustrates the delivery catheter <NUM> inside the left ventricle <NUM> with the distal tip 10a just below the native mitral valve leaflets <NUM>, <NUM>. The procedure has been initiated with exposure of the contents of the delivery system.

<FIG> illustrates another portion of the procedure subsequent to <FIG> and illustrating that the prosthetic or replacement mitral valve <NUM> has been partially delivered through the distal end 10a of the catheter <NUM>. The end of the replacement valve <NUM> that is positioned in the left ventricle <NUM> has arms <NUM> that wrap around the native mitral leaflets <NUM>, <NUM> and serve to anchor the replacement valve <NUM> firmly against the margins of the native mitral valve leaflets <NUM>, <NUM>. The arrows <NUM> show how the arms <NUM> have wrapped around the lower margins of the native mitral leaflets <NUM>, <NUM> after the arms <NUM> have been extruded or deployed outwardly from the delivery catheter <NUM>. This replacement valve <NUM> construction has been shown in the above-mentioned PCT Application Serial No. <CIT>. These arms <NUM> will help prevent the replacement valve <NUM> from dislodging upward into the left atrium <NUM> when the replacement valve <NUM> is fully positioned, because the arms <NUM> hook around the edges of the native mitral leaflets <NUM>, <NUM>. Multiple arms <NUM> are useful to provide a lower plane of attachment of the mitral valve prosthesis <NUM> to the native mitral valve <NUM>. The arms <NUM> may vary in length and in character and construction. It will be understood that a plurality of arms <NUM> is used here, but only two arms <NUM> are shown in these figures for purposes of illustration and simplification. One of the arms <NUM> includes a loop <NUM> to direct or control the helical anchor delivery catheter <NUM> that contains a helical anchor <NUM>. The anchor delivery catheter <NUM> has been preloaded into the loop <NUM> before the assembly was loaded into the delivery sheath <NUM>. The arm with the loop <NUM> may be of heavier construction than the other arms <NUM> and does not have to resemble the other arms <NUM>. The arms <NUM> have shape memory property such that when they are extruded or deployed outwardly from the anchor catheter <NUM> they wrap around the native mitral leaflets <NUM>, <NUM>. The arm <NUM> with the loop <NUM> wraps around the native mitral leaflets <NUM>, <NUM> and the attached helical anchor delivery catheter <NUM> is carried with it so that the chordae <NUM> and the native mitral valve leaflets <NUM>, <NUM> are positioned inside the exposed end of the helical anchor <NUM>.

When the helical anchor <NUM> is advanced or extruded as is initially shown in <FIG>, it will encircle the chordae tendinae <NUM> so that all valve and chordae will be trapped inside the helical anchor <NUM>. The loop <NUM> swings the helical anchor delivery catheter <NUM> around the native mitral leaflets <NUM>, <NUM> and above the chordae <NUM> into a preferred position under the native mitral valve annulus <NUM>. The arm <NUM> with the loop <NUM> may have a dual function of attachment of the valve <NUM> to the native leaflet margin and for guidance during delivery of the helical anchor <NUM>. The loop <NUM> may be sufficiently large to allow the helical anchor delivery catheter <NUM> to pivot or swivel as the system is deployed. It is important for the helical anchor <NUM> to be extruded in a plane close to parallel to the underside of the native mitral valve <NUM>. The helical anchor delivery catheter <NUM> is also aimed or oriented to this plane by the loop <NUM>. The loop <NUM> may, in fact, be composed of a short tube (not shown) instead of a wire as shown. A tube would force the helical anchor delivery catheter <NUM> into a favorable plane and orientation. Alternatively, the helical anchor delivery catheter <NUM> could be steerable in one of the manners known through steerable catheter technology.

Other mitral valve prosthesis or replacement valves may be used and have a wide range of attachment arms or wings, or stent structure, that wrap around the native mitral valve leaflets <NUM>, <NUM>. The arms or other similar structures in such prostheses could all be fitted with a loop <NUM>, or tube or other similar guidance structure, to perform similar functions as the loop <NUM> described immediately above. This function generally relates to directing the delivery of the helical anchor <NUM>. Furthermore, it is not necessary that a loop <NUM> directs the helical anchor delivery. For example, a cell or opening of the replacement valve stent structure <NUM> could also perform the same function as the loop <NUM> shown and described in these figures. A hook or a tube may also be used in lieu of the illustrated loop <NUM>. Any structure that can function to direct the helical anchor <NUM> around the native mitral valve leaflets <NUM>, <NUM> may be added to the prosthetic or replacement heart valve <NUM>. The structure may be permanently fabricated as part of the replacement valve <NUM> or may be temporary structure used only during the procedure. For example, a loop of suture (not shown) may be used to guide delivery of a helical anchor <NUM> including any helical anchor delivery catheter <NUM> associated therewith. After use of the suture, it may be withdrawn from the patient.

The arms <NUM> illustrated in these figures are quite narrow or slender. In practice, it may be more useful to have arms that are composed of pairs or triplets of wires that are fused at the ends. The narrow terminal ends of the arms <NUM> facilitate the arms <NUM> passing between the chordae tendinae <NUM> at their margins with the free edge of the native mitral leaflets <NUM>, <NUM> to allow the arms <NUM> to wrap around the native leaflets <NUM>, <NUM>. The chordae <NUM> are closely packed in some areas and slender arms <NUM> will allow the arms <NUM> to pass between the chordae tendinae <NUM>. Once the slender portion of the arms <NUM> pass, thicker portions of the arms <NUM> may move between the chordae <NUM> by spreading them apart. Therefore, an arm <NUM> that is slender or composed of a single wire or fusion of wires at the tip and that is more robust or thicker closer to the main body of the prosthetic or replacement valve <NUM>, may be a desirable arrangement. The wires or arms <NUM> may also be much shorter than those shown in these illustrative figures. In the illustrated method, delivery of the helical anchor <NUM> may be started at any desired location and not necessarily at the commissure <NUM> of the native mitral valve <NUM>. For example, delivery may start in the middle portion of a native mitral leaflet <NUM> or <NUM>. This would be advantageous for the surgeon who would not have to precisely locate the commissure <NUM> to begin the procedure, thereby greatly simplifying the procedure.

<FIG> illustrates the helical anchor <NUM> being delivered under the native mitral leaflets <NUM>, <NUM>. The arrow <NUM> indicates the helical anchor <NUM> being extruded from the helical anchor delivery catheter <NUM> under the native mitral valve <NUM>. Any number of coils or turns <NUM> of the helical anchor <NUM> may be extruded depending on the particular configuration of helical anchor <NUM> being used in the procedure. The inner diameter of the helical anchor <NUM> would preferentially be slightly less than the outer diameter of the fully expanded mitral valve prosthesis <NUM> to promote firm engagement or anchoring of the replacement mitral valve <NUM>. The helical anchor <NUM> may be composed of bare wire, or may have coatings or coverings for various reasons such as those described in the above-mentioned PCT applications. The partially delivered mitral valve prosthesis <NUM> serves an important function to center the delivery of the helical anchor <NUM>. The mitral valve prosthesis or replacement valve <NUM> also provides a stable platform.

<FIG> illustrates that three turns <NUM> of the helical anchor <NUM> have been placed below the native mitral valve <NUM>. These turns or coils <NUM> have positioned the native mitral valve leaflets <NUM>, <NUM> between the helical anchor <NUM> and the prosthetic mitral valve <NUM> which is shown in a configuration about to be expanded. Once the replacement valve <NUM> is expanded, this securely positions the replacement valve <NUM> and prevents leaks around the replacement valve <NUM> by sealing the native mitral leaflets <NUM>, <NUM> to the prosthesis <NUM>. The delivery sheath <NUM> for the replacement valve <NUM> has been removed and when using a self-expanding valve, the valve <NUM> would spring open upon removal of the delivery sheath <NUM>. The arrows <NUM> indicate this process prior to its occurrence. In this figure, the replacement valve <NUM> is still in a closed position to allow clear visualization of the turns or coils <NUM> of the helical anchor <NUM> beneath the native mitral valve <NUM>. In this configuration, there are three helical anchor coils <NUM> below the native mitral valve <NUM>, however, any number of coils <NUM> may be used instead. The coils <NUM> are positioned up against the underside of the mitral valve annulus <NUM> and leaflets <NUM>, <NUM> to provide a solid buttress to fix the helical anchor <NUM> in position and prevent movement into the left atrium <NUM> when the powerful left ventricle <NUM> contracts. When the arms <NUM> wrap around the helical anchor <NUM>, the entire structure or assembly is stabilized in position. This example provides a surgeon or interventionalist a considerable amount of choice due to the fact that the anchor <NUM> may be delivered at the same time as the replacement valve <NUM>. Many shape memory framed prosthetic heart valves <NUM> may be re-sheathed. This means that during a procedure, the replacement valve <NUM> may be partially advanced from a catheter or sheath <NUM> and tested for its fit in the heart <NUM>. If the surgeon or interventionalist is not satisfied with the positioning of the replacement valve <NUM> before the final release of the replacement valve <NUM>, this valve <NUM> may be pulled back into the sheath or catheter <NUM>. Therefore, a prosthetic or replacement valve <NUM> may be positioned initially with no helical anchor <NUM> in place. If subsequent anchoring appeared strong and stable and there was no evidence of movement or leakage, the valve <NUM> may be released. On the other hand, if the surgeon or interventionalist is not satisfied, the valve <NUM> may be pulled back into the sheath <NUM>. The helical anchor <NUM> may be implanted first, and then the valve <NUM> may be extruded from the delivery sheath <NUM>. This would allow the user to decide on the clinical need for additional anchoring under the native mitral valve <NUM>.

<FIG> illustrates the fully implanted expandable replacement valve <NUM> shown in proper position. The arms <NUM> have wrapped around the native mitral valve leaflets <NUM>, <NUM> to prevent the replacement valve <NUM> from moving upward into the left atrium <NUM>. The native mitral leaflets <NUM>, <NUM> are compressed under the arms <NUM> and a very solid mechanical structure and anchoring has been created to prevent the replacement valve <NUM> from migrating to an undesirable position. The turns or coils <NUM> of the helical anchor <NUM> also compress against the body <NUM> of the prosthetic or replacement valve <NUM> to position, orient and prevent movement of the replacement valve <NUM>. Therefore, the helical anchor <NUM> provides a friction attachment of the replacement valve <NUM> and serves to anchor the arms <NUM> that wrap around the helical anchor <NUM>. The upper portion of the native mitral valve <NUM> is shown with a wider area that sits inside the left atrium <NUM> to promote attachment to the wall of the left atrium <NUM>. However, the force moving the replacement valve <NUM> from the left atrium <NUM> toward the left ventricle <NUM> is low and this portion of the replacement valve <NUM> may not be necessary and could be eliminated or reduced from a clinical prosthesis. The turns or coils <NUM> of the helical anchor <NUM> are important because they can overcome a wide variety of variations in the lengths of the native mitral leaflets <NUM>, <NUM> from patient to patient and the length of the chordae tendinae <NUM> and the attachment points of the chordae <NUM> in the left ventricle <NUM>. When a replacement valve <NUM> with arms <NUM> wrapping around the native mitral leaflets <NUM>, <NUM> is used without any helical anchor <NUM> encircling under the native leaflets <NUM>, <NUM>, the depth of fixation of the prosthetic mitral valve <NUM> may vary around the perimeter of the implanted replacement valve <NUM>. For example, if the chordae tendinae <NUM> attached to the middle part of the posterior leaflet <NUM> were very elongated or ruptured, which is a common situation, the arms <NUM> may fail to wrap around and engage the native leaflet <NUM> at this location. Alternatively, there may be a very limited engagement along or at a much higher plane. This portion of the replacement valve <NUM> would be positioned higher, creating a skew in the replacement valve <NUM> so that the replacement valve <NUM> would be positioned at an angle to the plane of inflowing blood through the replacement valve <NUM>. As the heart <NUM> beats, there is a large load on the replacement valve <NUM> and it may begin to rock and shift. The heart <NUM> beats almost <NUM>,<NUM> times per day and after several days or weeks or months, the valve <NUM> may shift, move and/or dislodge. Also, if the leaflets <NUM>, <NUM> and/or chordae <NUM> were very elongated, there may be no contact with the arms <NUM>. This could result in a large perivalvular leak due to lack of engagement of the replacement valve <NUM> with the native mitral leaflets <NUM>, <NUM>. An anchor <NUM> under the native mitral valve leaflets <NUM>, <NUM> would compress native leaflet tissue against the replacement valve <NUM> and prevent this problem. The helical anchor <NUM> would be positioned in one plane and prevent problems related to variations in patient anatomy.

In clinical practice, there are virtually limitless variations in the size of the native mitral leaflets <NUM>, <NUM>, character of the native mitral leaflets <NUM>, <NUM>, the chordal lengths and the attachment of the chordae <NUM> as well as the diameter of the mitral annulus <NUM>. The use of a helical anchor <NUM> or other anchor structure under the native leaflets <NUM>, <NUM> neutralizes many of these variables since the fixation point of the arms <NUM> may be brought to the lowest coil <NUM> of the helical anchor <NUM>. This position may also be determined in advance by selecting the number of coils <NUM> in the helical anchor <NUM> as well as the thickness of the coils <NUM> in the helical anchor <NUM> to match the turning point of the arms <NUM> on the lowest portion of the replacement valve <NUM>. Thus, an important feature of the helical anchor <NUM> delivered under the native mitral annulus <NUM> is that it can create a common and predefined plane for anchoring the arms <NUM> of the replacement valve <NUM>. In the situation described above in which some of the chordae <NUM> are stretched, the attachment in this region of the replacement valve <NUM> could be to the helical anchor <NUM>. This would create a common plane for the lowest point on the replacement valve <NUM>. To ensure that the valve <NUM> anchors at a common lowest plane throughout its perimeter, additional coils <NUM> may be added to the helical anchor <NUM>, or the diameter of the coils <NUM> may be made larger. Additional options are, for example, waves or undulations may be added to the coils <NUM> of the helical anchor <NUM> to expand the overall height of the helical anchor <NUM>. The helical anchor <NUM> therefore improves stability of the replacement valve <NUM> by providing an anchoring point or location for the arms of the replacement valve <NUM> to wrap around while, at the same time, the helical anchor <NUM> can trap the perimeter of the replacement valve <NUM> along its length. The combination of these features provides for increased stability to the replacement valve <NUM> and can also seal the replacement valve <NUM> against the native mitral valve <NUM> to prevent perivalvular leakage of blood flow. As mentioned, the native mitral valve and heart structure of patients comes in many varieties and combinations. It is not practical for a manufacturer to make different lengths and depths of anchoring arms <NUM> and for the user to deliver these products optimally into position for each case. Rather, it is much more practical to adjust for these variations by placing a helical anchor <NUM> below the native mitral valve <NUM> and using this to create a lowest plane for the arms <NUM> to anchor against. The delivery system for the helical anchor <NUM> may be any delivery or deployment system, for example, described in the above-mentioned PCT applications. It will be appreciated that such deployment methods and apparatus may be used to deliver the helical anchor <NUM> such that the anchor <NUM> is positioned only below the native mitral valve <NUM> as shown herein.

<FIG> illustrate a loop <NUM> that is provided at the end of an arm <NUM> on the replacement valve <NUM> that guides the helical anchor delivery catheter <NUM>. This loop <NUM> allows the delivery catheter <NUM> to swivel as it is moved into position. Here, the helical anchor delivery catheter <NUM> passes through the replacement valve <NUM> or, in other words, within the replacement valve body <NUM>, however, it may be directed in manners other than that shown, and the helical anchor delivery catheter <NUM> may be used for additional guidance along the path, such as by being steerable after being directed through the loop <NUM> farther than as shown in <FIG> for delivery of the helical anchor <NUM>.

<FIG> illustrate a helical anchor delivery tube <NUM> that has been incorporated into the replacement valve <NUM> instead of the helical anchor delivery catheter <NUM> previously described. Here, one arm of the replacement valve <NUM> is, in fact, the tube <NUM> that is loaded with and carries the helical anchor <NUM>. When the tubular arm <NUM> wraps around the native mitral valve leaflet (not shown), the helical anchor <NUM> is carried into the correct location and to the correct plane for delivery. Any structure on one of the arms <NUM> of the replacement valve <NUM> or any portion of the replacement valve <NUM> that may guide the helical anchor <NUM> for delivery may be used instead. In <FIG>, the helical anchor <NUM> has been extruded from the tubular arm <NUM> for almost one complete rotation or turn. As previously described, multiple turns or coils <NUM> of the helical anchor <NUM> may be deployed in this manner for ultimately securing the replacement valve <NUM> at the native mitral valve <NUM> location generally as described above. The main difference with this example is that a helical anchor delivery catheter <NUM> is not needed.

<FIG> illustrate replacement valve and helical anchor deployment and implantation. In this regard, the helical anchor delivery catheter <NUM> and the replacement valve <NUM> are essentially delivered side by side. <FIG> illustrates the helical anchor delivery catheter <NUM> outside or extruded from the delivery sheath <NUM> that also delivers the replacement valve <NUM>. The helical anchor delivery catheter <NUM> passes through a loop <NUM> in one of the arms <NUM> of the replacement valve <NUM>. The arrow <NUM> indicates that the helical anchor <NUM> is about to be extruded from the end of the helical anchor delivery catheter <NUM>. As shown in <FIG>, with the end of the helical anchor delivery catheter <NUM> still in the loop <NUM>, almost one full turn or coil <NUM> of the helical anchor <NUM> has been delivered under the native mitral valve (not shown). <FIG> illustrates a further point during the implantation process in which about three turns or coils <NUM> of the helical anchor <NUM> have been delivered under the plane <NUM> of the native mitral valve <NUM>. In this figure, the helical anchor delivery catheter <NUM> and the sheath <NUM> delivering the replacement valve <NUM> have been removed. When the replacement valve <NUM> is formed with a self-expanding stent, the body <NUM> of the valve <NUM> will spring open when the delivery sheath <NUM> is removed. For purposes of clarity and illustration, the valve <NUM> is still shown in a closed or unexpanded state simply for clarity. However, in general, the fully implanted system or assembly will be similar to that shown in <FIG>.

<FIG> illustrate another helical anchor <NUM>. Here, the configuration of the helical anchor <NUM> in terms of the spacings and size of the coils <NUM> may vary. The cross-sectional construction includes a fabric covering <NUM> which may, for example, be PET having a thickness of <NUM> +/- <NUM> inch (<NUM> +/- <NUM>), a weight of <NUM> +/- <NUM> ounce/yard<NUM> (<NUM> +/- <NUM> grams/m<NUM>), a wale/inch of <NUM> +/- <NUM> (<NUM> +/- <NUM> wale/cm), courses/inch of <NUM> +/-<NUM> (<NUM> +/- <NUM> courses/cm). A foam layer <NUM> may, for example, be <NUM> thick polyurethane sheet material. The foam may be attached to the fabric <NUM> using PTFE suture with a light straight stitch. The fabric160 and foam <NUM> may then be folded around the center wire portion 22a of the coils <NUM> of the helical anchor <NUM> and cross-stitched to the wire portion 22a using fiber suture.

<FIG> illustrates another system which may include the delivery of a helical anchor <NUM> as set forth above and/or in the above-mentioned PCT applications. In accordance with this example, however, an additional tissue gathering device <NUM> is included in the delivery system. The device <NUM> delivers a temporary ring or loop <NUM> which can corral or surround the bundles of chordae tendinae <NUM> into a smaller area. This can facilitate easier placement of the helical anchor <NUM> without entanglement or obstruction with the chordae tendinae <NUM>. Also, shown in this figure is an introducer sheath <NUM>, a delivery catheter <NUM> as well as a steerable helical anchor delivery catheter <NUM> all generally as previously described.

<FIG> illustrate another helical anchor device or assembly <NUM>. The assembly <NUM> is comprised of an upper or atrial helical anchor portion <NUM> as well as a lower or ventricular helical anchor portion <NUM>. These helical anchor portions <NUM>, <NUM> are delivered simultaneously by extruding out of a helical anchor delivery catheter <NUM>. The lower anchor portion <NUM> is delivered through the mitral valve <NUM> between the native leaflets <NUM>, <NUM>. The upper and lower anchor portions <NUM>, <NUM> may be coupled together, for example, by a crimp joint <NUM>. The upper anchor portion <NUM> is deployed above the native mitral valve <NUM> in the left atrium <NUM> (<FIG>). The upper and lower anchor portions <NUM>, <NUM> may be staggered such that the lower anchor portion <NUM> is initially directed into the commissure <NUM> and through the native mitral valve <NUM>. As shown, the upper and lower helical anchor portions <NUM>, <NUM> wind or rotate in opposite directions and then may be crimped together, as shown or may be precrimped or otherwise attached prior to loading the catheter <NUM>.

<FIG> illustrate another helical anchor and replacement valve system similar to those discussed in connection with the above-mentioned PCT Application Serial No. <CIT>. Here, however, the configuration of the helical anchor <NUM> is shown to have a gap <NUM> between at least the upper coils 22a and the native mitral valve <NUM>. As in the above-mentioned PCT application, the helical anchor <NUM> includes an annular seal <NUM> of any desired configuration extending lengthwise through or otherwise along the length of the anchor <NUM>. Here, a panel or membrane seal <NUM> is shown extending downwardly from one of the coils 22a and covering the portion of the stent mounted replacement valve <NUM> that would otherwise be open due to the stent structure <NUM>. The seal <NUM> therefore prevents leakage of blood past the replacement valve <NUM> through the open stent structure <NUM>. All other aspects of the assembly as shown in <FIG> are as described herein and may include any of the options or features described herein or otherwise, for example, in the above-mentioned PCT applications. The gap <NUM> is formed by a coil portion 22b extending non-parallel to the adjacent coil portions 22a, 22c.

Claim 1:
A system for replacing a native heart valve, the system comprising:
an expansible helical anchor (<NUM>) formed as multiple coils (<NUM>) adapted to support a heart valve prosthesis (<NUM>), at least one of the coils normally being at a first diameter, and being expandable to a second, larger diameter upon application of radial outward force from within the helical anchor (<NUM>);
an expansible heart valve prosthesis (<NUM>) capable of being delivered into the helical anchor (<NUM>) and expanded inside the multiple coils (<NUM>) into engagement with the at least one coil to move the at least one coil from the first diameter to the second diameter while securing the helical anchor (<NUM>) and the heart valve prosthesis (<NUM>) together, wherein the expansible heart valve prosthesis (<NUM>) includes a blood inflow end and a blood outflow end,
characterized in that the system further comprises:
a sealing layer (<NUM>, <NUM>) covering an outflow portion of the expansible heart valve prosthesis (<NUM>) configured to engage the helical anchor (<NUM>) and prevent blood leakage past the heart valve prosthesis (<NUM>) after implantation of the heart valve prosthesis (<NUM>) in the helical anchor (<NUM>), and
an internal layer (<NUM>) added to an annular edge of the blood outflow end of the expansible heart valve prosthesis (<NUM>), wherein the internal layer (<NUM>) is covered by the sealing layer (<NUM>, <NUM>) to form a bumper (<NUM>) for preventing damage to tissue structure in the heart after implantation.