HK1202043B - Quick-connect prosthetic heart valve and methods - Google Patents

Description

Quick connect prosthetic heart valve and method

The application is a divisional application, and the original international application has the application date of 12-18 th in 2009, the application number of 200980151123.2(PCT/US2009/068693), and the name of the invention is 'quick-connection artificial heart valve and method'.

Technical Field

This application claims priority under 35u.s.c. § 119(e) of U.S. provisional application No. 61/139,398 filed 12, 19, 2008.

The present invention generally relates to prosthetic valves for implantation in body passages. More particularly, the present invention relates to prosthetic heart valves configured for surgical implantation in less time than current valves.

Background

In vertebrates, the heart is a hollow muscular organ with four pumping chambers as seen in fig. 1: the left and right atria and the left and right ventricles, each with its own one-way valve. The native heart valves are identified as the aortic, mitral (or mitral), tricuspid, and pulmonary valves, each of which is mounted in an annulus comprising a dense fibrous ring of muscle fibers that are connected directly or indirectly to the atria and ventricles. Each ring defines a flow orifice.

The atrium is the blood-receiving chamber, which pumps blood into the ventricle. The ventricle is a blood discharge chamber. The wall is composed of fibrous and muscular parts, called the interatrial septum, which separates the right atrium and the left atrium (see fig. 2 to 4). The fibrous atrial septum is a substantially stronger tissue structure than the more fragile heart muscle tissue. The anatomical landmark on the interatrial septum is an oval, thumb-sized depression, called the oval fossa or the oval capsular crypt (shown in fig. 4).

The synchronized pumping action of the left and right sides of the heart constitutes the cardiac cycle. The cycle begins with a ventricular diastole phase called ventricular diastole. The cycle ends with a ventricular systole called ventricular contraction. The four valves (see fig. 2 and 3) ensure that blood does not flow in the wrong direction during the cardiac cycle, i.e. that blood does not flow back from the ventricles into the corresponding atria, or from the atria into the corresponding ventricles. The mitral valve is between the left atrium and the left ventricle, the tricuspid valve is between the right atrium and the right ventricle, the pulmonary valve is at the opening of the pulmonary artery, and the aortic valve is at the opening of the aorta.

Fig. 2 and 3 show the anterior (a) portion of the mitral annulus adjacent to the aortic valve noncircular semilunar valve. The mitral annulus is in the vicinity of the left coronary artery circumflex, and the posterior (P) side is proximal to the coronary sinus and its branches.

The mitral and tricuspid valves are defined by fibrous rings of collagen, each called an annulus, which forms part of the fibrous skeleton of the heart. The annulus provides a circumferential attachment to two tips or leaflets of the mitral valve (referred to as the anterior and posterior tips) and three tips or leaflets of the tricuspid valve. As seen in fig. 1, the free edges of the lobes are connected to the chordae tendineae of more than one papillary muscle. In a healthy heart, these muscles and their chordae tendineae support the mitral and tricuspid valves, forcing the leaflets against the high pressures that develop during contraction (pumping) of the left and right ventricles.

When the left ventricle contracts after filling with blood from the left atrium, the ventricle wall moves inward and releases some of the tension from the papillary muscles and cords. Pushing blood under the mitral valve leaflets causes them to rise toward the annulus plane of the mitral valve. As they advance toward the annulus, the leading edges of the anterior and posterior leaflets meet, forming a seal and closing the valve. In a healthy heart, leaflet coaptation occurs at a plane close to the mitral annulus. The blood continues to be pressurized in the left ventricle until it shoots into the aorta. Contraction of the papillary muscles occurs simultaneously with contraction of the ventricle and serves to keep healthy valve leaflets tightly closed at the maximum systolic pressure produced by the ventricle.

Various surgical techniques may be used to repair diseased or damaged valves. In a valve replacement procedure, the damaged leaflets are excised and the annulus is shaped to receive a replacement valve. Due to aortic stenosis and other heart valve diseases, thousands of patients per year undergo surgery in which a defective native heart valve is replaced by a prosthetic valve, either biological or mechanical. Another less powerful approach to treating defective valves is through repair or reconstruction, which is typically used on minimally calcified valves. The problem with surgical treatment is significant trauma, which imposes high morbidity and mortality rates associated with surgical repair on these chronic patients.

When replacing the valve, surgical implantation of the prosthetic valve typically requires an open chest procedure during which the heart is stopped and the patient is placed on a cardiopulmonary bypass machine (a so-called "heart-lung machine"). In one common surgical procedure, the diseased native valve leaflets are excised and a prosthetic valve is sutured to the surrounding tissue at the valve annulus. Some patients do not survive a surgical procedure or die shortly thereafter due to the trauma associated with the procedure and the duration of care of extracorporeal blood circulation. It is well known that the risk to the patient increases with the amount of time required for extracorporeal circulation. Because of these risks, a large number of patients with defective valves are considered inoperable because their condition is too frail to survive the procedure. According to some estimates, about 30 to 50% of subjects with aortic stenosis over the age of 80 years are unable to undergo surgery for aortic valve replacement.

Percutaneous and minimally invasive surgical approaches are gaining strong attention due to the drawbacks associated with conventional open-heart surgery. In one technique, the prosthetic valve is configured to be implanted by catheterization, a much less invasive procedure. For example, U.S. patent No. 5,411,552 to Andersen et al describes a collapsible valve that is percutaneously introduced in a compressed state via a catheter and expanded at a desired location by balloon inflation. While these remote implantation techniques have shown great promise for treating certain patients, replacing the valve by surgical intervention remains a preferred treatment procedure. One obstacle to receiving remote implantation is resistance from physicians who understandably are anxious about transitioning from an effective, if not perfect, regimen to a new method that promises significant results but is relatively exotic. Regulatory agencies worldwide are also slowly pushing, coupled with the understandable caution performed by surgeons in the new technology being converted to heart valve replacement. Numerous successful clinical trials and follow-up studies are in progress, but will require more experience with these new technologies before they are fully accepted.

Accordingly, there is a need for improved devices and associated methods of use in which a prosthetic valve can be surgically implanted in a body conduit in a more efficient procedure that reduces the time required for extracorporeal circulation. It would be desirable if such devices and methods could help patients who are deemed inoperable with a defective valve because the condition of such patients is too weak to withstand lengthy conventional surgical procedures. The present invention addresses these needs and others.

Summary of The Invention

Various embodiments of the present application provide prosthetic valves and methods of use for replacing a defective native valve in a human heart. Certain embodiments are particularly suitable for use in surgical procedures that quickly and easily replace heart valves while minimizing the time in which extracorporeal circulation (i.e., bypass pumps) is used.

In one embodiment, a method of treating a native aortic valve in a human heart to replace aortic valve function, comprising: 1) access to the native valve through an opening in the chest; 2) advancing the expandable base stent to a native aortic valve position, the base stent being radially compressed during the advancing; 3) radially expanding the base stent at the native aortic valve location; 4) advancing a valve element within a lumen of a base stent; and 5) expanding the attachment stent over the valve element to mechanically attach to the base stent in a quick and efficient manner.

In one variation, the base support may comprise a metal frame. In one embodiment, at least part of the metal frame is made of stainless steel. In another embodiment, at least a portion of the metal frame is made of a shape memory material. The valve element may take various forms. In a preferred embodiment, the valve element comprises biological tissue. In another variation of the method, the metal frame is viewed under fluoroscopy during advancement of the prosthetic valve to the native aortic valve.

The native valve leaflets can be removed prior to delivery of the prosthetic valve. Alternatively, the native leaflets can be placed in position to reduce surgical time and provide a stable base for anchoring the base stent within the native valve. In one advantage of this method, the native leaflets are retracted inward to enhance fixation of the metal frame in the body duct. When the native leaflets are in place, a balloon or other expansion element can be used to push the abnormal valve leaflets and thus enlarge the native valve prior to implantation of the base stent. The native rings can be expanded from their original orifice size to between 1.5-5mm to accommodate larger sized prosthetic valves.

According to a preferred aspect, a prosthetic heart valve system includes a base stent adapted to anchor a heart valve annulus and define an orifice therein, and a valve element coupled to the base stent. The valve element comprises a prosthetic valve defining a non-expandable, non-collapsible orifice therein and an expandable connecting stent extending from an inflow end thereof. The connecting stent has a contracted state for delivery to an implantation site and an expanded state configured for outward connection to a base stent. The base stent may also be expandable, with a contracted state for delivery to an implantation site adjacent the heart valve annulus and an expanded state sized to connect and anchor the heart valve annulus. Desirably, both the base stent and the linking stent are plastically expandable.

In one embodiment, the prosthetic valve comprises a commercially available valve having a sewing ring, and the connecting stent is attached to the sewing ring. The contracted state of the connecting stent may be conical, tapering in the distal direction. The linking scaffold preferably comprises a plurality of radially expandable struts, at least some of which are arranged in rows, with the most distal row having the greatest capacity to expand from a collapsed state to an expanded state. Still further, the row of struts furthest from the prosthetic valve has alternating cusps and valleys, wherein the base stent includes holes in which the cusps connecting the stents may protrude to join the two stents. The base stent may include a plurality of radially expandable struts between axially positioned struts, wherein at least some of the axially positioned struts have higher projections that differentiate locations around the stent.

Also disclosed herein are methods of delivery and implantation of a prosthetic heart valve system, comprising the steps of:

advancing the base stent to an implantation position adjacent the heart valve annulus;

anchoring the base stent to the heart valve annulus;

providing a valve element comprising a prosthetic valve having a non-expandable, non-collapsible orifice, the valve element further comprising an expandable connecting stent extending from an inflow end thereof, the connecting stent having a collapsed state for delivery to an implantation site and an expanded state configured for outward connection to a base stent;

advancing the valve element with the attached stent in its contracted state to an implantation site adjacent the base stent; and

the connecting bracket is expanded to an expanded state, and is contacted and connected with the basic bracket.

The base stent may be plastically expandable, the method further comprising advancing the expandable base stent to an implantation position in a contracted state, and plastically expanding the base stent to an expanded state, contacting and anchoring to the heart valve annulus, increasing the orifice size of the heart valve annulus by at least 10% or 1.5-5mm in the process. Desirably, the prosthetic valve of the valve element is selected to have an orifice size that matches the increased orifice size of the heart valve annulus. The method further includes mounting the base stent on a mechanical dilator, and deploying the base stent over the heart valve annulus using the mechanical dilator.

One embodiment of the method further comprises mounting the valve element on a holder having a receptacle and a lumen through a proximal end thereof. The holder is mounted at the distal end of a handle having a lumen therethrough, and the method includes passing a balloon catheter through the lumen of the handle and holder and within the valve element, and inflating the balloon on the balloon catheter to expand the connecting stent. The valve element mounted on the holder can be packaged separately from the handle and balloon catheter. Desirably, the contracted state of the linking stent is conical, and the balloon on the balloon catheter has a distal expanded end that is larger than its proximal expanded end so as to impart a greater expansion deflection to the linking stent than to the prosthetic valve.

In methods in which the connecting stent is conical, the connecting stent may comprise a plurality of radially expandable struts, at least some of which are arranged in rows, wherein the row furthest from the prosthetic valve has the greatest ability to expand from the collapsed state to the expanded state.

The method may utilize an attachment stent having a plurality of radially expandable struts, wherein the row furthest from the prosthetic valve has alternating cusps and depressions. The distal end of the connecting stent is thus expanded more than the rest of the connecting stent so that the cusps in the row furthest from the prosthetic valve protrude outward into the ostium of the base stent. Both the base stent and the linking stent may have a plurality of radially expandable struts between axially positioned struts, wherein the method comprises positioning the linking stent such that its axially positioned struts are out of phase with those of the base stent to increase retention therebetween.

Another aspect described herein is a system for delivering valve elements including a prosthetic valve having a non-expandable, non-collapsible aperture, and an expandable connecting stent extending from an inflow end thereof, the connecting stent having a contracted state for delivery to an implantation site and an expanded state. The delivery system includes a valve holder connected to a distal end of the valve element, a balloon catheter having a balloon, and a handle configured to connect to a proximal end of the valve holder, the handle having a lumen for passage of the catheter, wherein the balloon extends distally through the handle, past the holder, and through the valve element. In the system, the prosthetic valve is preferably a commercially available valve having a sewing ring to which the attachment stent is attached.

The contracted state of the connecting stent in the delivery system may be conical, tapering in the distal direction. In addition, the balloon catheter may further include a generally conical nose cone on its distal end that extends through the valve element and engages the distal end of the stent in its contracted state. Desirably, the handle comprises a proximal portion and a distal portion connectable together in series to form a continuous lumen, wherein the distal portion is adapted to connect to the receptacle of the holder to enable manual manipulation of the valve element using the distal portion prior to connection with the proximal handle portion. Preferably, the balloon catheter and proximal handle portion are packaged within the proximal portion lumen along with the balloon.

The system of claim 21, wherein the valve element mounted on the holder is packaged separately from the handle and the balloon catheter. A further understanding of the nature and advantages of the present invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.

Drawings

The invention will now be described, with reference to the accompanying schematic drawings, in which:

FIG. 1 is an anatomical front view of a human heart, partially open and partially viewing the interior of the chambers and adjacent structures of the heart;

FIG. 2 is an anatomical view of a portion of a human heart showing the tricuspid valve in the right atrium, the mitral valve in the left atrium, and the aortic valve therebetween, with the tricuspid and mitral valves open and the aortic and pulmonary valves closed during ventricular diastole (ventricular filling) of the cardiac cycle;

FIG. 3 is an anatomical view of the portion of the human heart shown in FIG. 2 with the tricuspid and mitral valves closed and the aortic and pulmonary valves open during ventricular systole (ventricular emptying) of the cardiac cycle;

FIG. 4 is an anatomical front perspective view of the left and right atria, partially open and partially showing the interior of the chambers of the heart and associated structures, such as the fossa ovalis, the coronary sinus, and the left coronary vein;

FIGS. 5A-5H are cross-sectional views through a separated aortic annulus, showing portions of the adjacent left ventricle and aorta, and illustrating various steps in an exemplary prosthetic heart valve system deployment of the present invention;

FIG. 5A shows a deflated balloon catheter having a base stent thereon that is advanced to the location of the aortic annulus;

FIG. 5B shows a balloon on a catheter inflated to expand and deploy a base stent near the aortic annulus;

fig. 5C shows a base stent deployed in an intra-aortic annular position;

FIG. 5D shows the valve element mounted on a balloon catheter advanced to a position within the base stent;

FIG. 5E shows the valve element in a desired implanted position within the aortic annulus and base stent, with the balloon catheter advanced farther to replace the disengaged nose cone with the connecting stent;

FIG. 5F shows a balloon on a catheter expanded to expand and deploy a valve element attachment stent in proximity to a base stent;

FIG. 5G shows a deflated balloon on the catheter, with the nose cone being removed from within the valve element;

FIG. 5H shows a fully deployed prosthetic heart valve of the present invention;

FIG. 6 is an exploded view of an exemplary system for delivering a prosthetic heart valve of the present invention;

FIG. 7 is an assembled view of the delivery system of FIG. 6, showing the nose cone extending beyond the distal end of the valve element attachment stent;

FIG. 8 is a view similar to FIG. 7 but with an alternative balloon catheter at the distal end to disengage the nose cone from the connecting stent;

FIG. 9 is an assembled view of a delivery system similar to that shown in FIG. 7 and showing a balloon inflated to expand the valve element attachment stent;

FIG. 10 is an exploded front view of several elements of the introduction system of FIG. 9, without the balloon catheter, valve element and retainer;

FIGS. 11A and 11B are perspective views of an exemplary valve element assembled to a valve holder of the present invention;

FIG. 11C is a side view of the assembly of FIGS. 11A and 11B;

11D and 11E are top and bottom views of the 11A and 11B assembly;

FIGS. 12A-12B illustrate an exemplary linking stent in a flattened configuration (12A) and a tubular expanded configuration (12B);

FIGS. 13A-13B illustrate an alternative linking stent having a discontinuous tip in a flattened and tubular expanded configuration;

FIGS. 14-17 are plan views of still further alternative attachment brackets;

18A-18B are flattened and tubular views of an exemplary base stent having superior position markers and a model connecting stent superimposed thereon;

FIG. 19 is a plan view of an alternative base bracket having an overlapping connecting bracket thereon;

FIG. 20 is a cross-sectional view of a linking bracket in the base bracket illustrating one method of interlocking; and

fig. 21-23 are perspective views of a device for delivering and expanding a base stent with mechanical fingers.

Detailed description of the preferred embodiments

The present invention seeks to overcome the disadvantages associated with conventional open heart surgery, while also employing some of the newer techniques that reduce the duration of the treatment procedure. The prosthetic heart valve of the present invention is primarily intended to be delivered and implanted using conventional surgical techniques, including open heart surgery as previously described. There are many routes in such surgery, all of which result in the formation of a direct access route to a particular heart valve annulus. For purposes of illustration, the direct access approach is one that allows direct (i.e., naked eye) visualization of the heart valve annulus. Further, it will be appreciated that embodiments of the two-stage prosthetic heart valve described herein may also be configured to be delivered using percutaneous methods and those minimally invasive surgical methods that require distant valve implantation using indirect visualization.

One main aspect of the present invention is a two-stage prosthetic heart valve in which the task of implanting the tissue anchors first and then the valve components is different and has certain advantageous results. An exemplary two-stage prosthetic heart valve of the present invention has an expandable base stent that is secured in place to tissue using a balloon or other expansion technique. The hybrid valve component having the non-expandable and expandable portions is then attached to the base stent in a non-connected or continuous operation. By utilizing an expandable base stent, the duration of the initial anchoring operation is greatly reduced as compared to conventional suturing operations utilizing a set of sutures. The expandable base stent may simply expand radially outward, contact the implant site, or may have additional anchoring devices such as barbs. This procedure can be performed using conventional open heart methods and cardiopulmonary bypass. In one advantageous feature, the time on bypass is greatly reduced due to the relative speed of implanting the expandable base stent.

For the sake of clarity, the term "base stent" refers to a structural member of a heart valve that is capable of attaching to the tissue of the heart valve annulus. The basic stents described herein are mostly typically tubular stents or stents with varying shapes or diameters. Stents are typically formed from a biocompatible metallic wire frame, such as stainless steel or Nitinol (Nitinol). Other basic stents that can be used with the valve of the present invention include rigid rings, horizontally-surrounding tube loops (spirally-outlet tubes), and other such tubes that fit closely within the valve loop and define an orifice therethrough for the passage of blood, or within which the valve component is mounted. However, it is fully contemplated that the base support may be a separate clip or hook that does not define a continuous edge. While such devices sacrifice some dynamic stability and speed and ease of deployment, these devices can be configured to work in conjunction with a particular valve component.

There is a distinction in the art between self-expanding and balloon expandable stents. Self-expanding stents may be crimped or otherwise compressed into a small tube and possess sufficient resilience to spring open by themselves when a restraint such as an outer sheath is removed. In contrast, balloon expandable stents are made of a substantially less elastic material and must in fact be plastically expanded from the inside outward when transitioning from a compressed diameter to an expanded diameter. It should be understood that the term balloon expandable stent includes a plastically expandable stent, whether or not a balloon is used to actually expand it. The material of the stent may plastically deform upon application of a deforming force, such as an expanding balloon or expanding mechanical fingers. Two options will be described below. Thus, the term "balloon expandable stent" should be considered to refer to the material or type of stent as opposed to a specific expansion device.

The term "valve component" refers to an element of a heart valve that has a fluid occluding surface to prevent blood flow in one direction while allowing blood flow in another direction. As mentioned above, various constructs are available in valve numbers, including those with elastic leaflets and those with rigid leaflets or spherical and cage structures. The leaflets may be bioprosthetic, synthetic or metallic.

The primary focus of the present invention is a two-stage prosthetic heart valve having a first stage in which a base stent is secured to the valve annulus, and a subsequent second stage in which a valve component is attached to the base stent. It should be noted that these stages can be performed at approximately the same time, such as if both elements are mounted on the same delivery device, or can be performed in separate clinical steps, where a base stent is deployed using a first delivery device, and then the valve component is deployed using the other delivery device. It should also be noted that the term "biphasic" refers to the two main steps of anchoring the structure to the annulus and then attaching the valve components, which does not necessarily restrict the valve to exactly two parts.

Another potential benefit of a two-stage prosthetic heart valve that includes a base stent and a valve component is that the valve component can be replaced after implantation without replacing the base stent. That is, an easily detachable device connecting the valve component and the base stent may be used, which allows for relatively easy implantation of a new valve component. Various structures for connecting the valve component and the base stent are described herein.

Thus, it should be understood that certain benefits of the present invention are independent of whether the base stent is expandable. That is, various embodiments describe an expandable base stent coupled to a hybrid valve component having a non-expandable and expandable portion. However, the same attachment structure can be used for the non-expandable base stent and the hybrid valve component. Accordingly, the invention is to be construed by reference to the appended claims.

As a further point of definition, the term "expandable" is used herein to refer to an element of a heart valve that is capable of expanding from a first delivery diameter to a second implant diameter. An expandable structure is therefore not meant to refer to a structure that may undergo slight expansion in response to a rise in temperature or other such incidental causes. Conversely, "non-expandable" should not be construed to mean completely rigid or dimensionally stable, as, for example, some slight expansion of a conventional "non-expandable" heart valve may be observed.

In the following description, the term "body conduit" is used to define a blood conduit or vessel within the body. Of course, the particular application of the prosthetic heart valve determines the body conduit in question. Aortic valve replacement, for example, would be implanted in or adjacent to the aortic annulus. Likewise, a mitral valve replacement will be implanted in the mitral valve annulus. Certain features of the present invention are particularly advantageous for an implantation site or otherwise. However, any of the heart valve embodiments described herein can be implanted into any body conduit unless combination is structurally impossible or excluded by the claim language.

Fig. 5A-5H are cross-sectional views through an isolated aortic annulus AA showing portions of the adjacent left ventricle LV and ascending aorta with sinus cavities (sinuses) S. Two coronary sinuses CS are also shown. The series of views shows snapshots of the various steps in deploying an exemplary prosthetic heart valve system of the present invention, which includes a two-element system. The first element is a base stent that is deployed near the native leaflets or, if the leaflets are excised, near the debrided aortic annulus AA. The second valve element is mounted within the base stent and anchored thereto. While two-part valves are known in the art, it is believed that the first time is the use of a stent within a stent that is connected to a non-expandable valve.

Fig. 5A shows catheter 20 having balloon 22 in a deflated state near the distal end, with tubular base stent 24 crimped over balloon 22. The stent 24 is shown in a radially collapsed, unexpanded configuration. The catheter 20 has been advanced to position the base stent 24 so that it is approximately axially centered at the aortic annulus AA.

Fig. 5B shows the balloon 22 on the catheter 20 inflated to expand and deploy the base stent 24 proximal to the aortic annulus AA, and fig. 5C shows the deployed base stent in place after the balloon 22 is deflated and the catheter 20 is removed. The stent 24 provides a base within and proximate to a body lumen (e.g., a valve annulus). Although the stent is described for illustrative purposes, any component capable of anchoring and then attaching the valve elements within and proximate to the body lumen may be used. In a preferred embodiment, the base support 24 comprises a plastically expandable fabric-covered stainless steel tubular support. One advantage of using a plastically-expandable stent is the ability to expand the native annulus to accept larger valve sizes than conventional procedures. Desirably, the Left Ventricular Outflow Tract (LVOT) is significantly expanded by at least 10%, or e.g., 1.5-5mm, and the surgeon can select a valve element 30 having a larger orifice diameter relative to the unexpanded annulus. In another aspect, the present invention may also use a self-expanding base stent 24, which is then reinforced by a subsequently implanted valve element 30. Because the valve member 30 has an incompressible portion, the prosthetic valve 34, and desirably the plastically-expandable connecting stent 36, it effectively resists recoil from the self-expanding base stent 24.

With continued reference to fig. 5B, the stent 24 has a diameter sized for deployment at a native valve site (e.g., along an aortic annulus). Portions of the stent 24 may expand outward into respective lumens adjacent the native valve. For example, in aortic valve replacement, the superior portion may expand into the region of the sinus cavity just downstream from the aortic annulus. Of course, care should be taken to orient (position ahead of) the stent 24 so as not to obstruct the tubular opening. The stent body is preferably configured with sufficient radial strength to push open and hold open the native leaflets under expansion. The natural leaflets provide a stable base for supporting the stent, thereby helping to securely anchor the stent in the body. To further secure the stent to the surrounding tissue, the lower portion may be configured with anchoring means such as, for example, hooks or barbs (not shown).

As will be described in greater detail below, the prosthetic valve system includes valve elements that can be quickly and easily attached to the stent 24. It should be noted here that the basic stent described herein may be of various designs, including the ones shown with diamond/herringbone (chevron-shaped) openings or other configurations. Depending on the manner of delivery (i.e., balloon or self-expanding), the stent may be a bald strut material or coated to promote ingrowth and/or to reduce paravalvular leakage. For example, a suitable covering often used is a sleeve of fabric such as Dacron (Dacron).

One of the main advantages of the prosthetic heart valve system of the present invention is the speed of deployment. Thus, the base stent 24 may take many different configurations as long as it does not require the time consuming process of suturing it to a loop. For example, another possible configuration of the base stent 24 is a base stent that is not fully expandable like the tubular stent shown. That is, the base stent 24 may have a non-expandable annular aperture from which an expandable edge stent or series of anchoring barbs are deployed.

Fig. 5D shows the valve element 30 mounted on a balloon catheter 32 that is advanced to a position within the base stent 24. The valve element 30 includes a prosthetic valve 34 and an attachment stent 36 attached to and protruding from an end thereof. In its radially collapsed or unexpanded state, the connecting stent 36 exhibits an inward taper that is conical in the distal direction. The catheter 32 extends through the valve element 30 and terminates at a distal nose cone 38 having a conical or bell-shaped configuration and covering the tapered end of the connecting stent 36. Although not shown, catheter 32 extends through the introducer sheath and valve holder.

When used in aortic valve replacement procedures, the prosthetic valve 34 preferably has three flexible leaflets that provide fluid occluding surfaces to replace the function of the native valve leaflets. In various preferred embodiments, the valve leaflets may be taken from another human heart (cadaver), cow (bovine), pig (porcine valve), or horse (equine). In other preferred variations, the valve component may comprise a mechanical element rather than biological tissue. The three leaflets are supported by three attached posts. An annulus is provided along a base portion of the valve member.

In a preferred embodiment, the prosthetic valve 34 comprises, in part, a commercially available, non-expandable prosthetic heart valve, such as Carpentier-Edwards PERIMOUNT, available from Edwards Lifesciences of Irvine, CaliforniaAn aortic heart valve. In this sense, a "commercially available" prosthetic heart valve is an off-the-shelf (i.e., suitable for stand-alone sale and use) prosthetic heart valve that defines a non-expandable, non-collapsible orifice therein and has a sewing ring that is implanted with sutures through an open-heart surgical procedure. The particular method of access to the heart used may vary, but the heart is stopped beating and opened during a surgical procedure, as opposed to a beating heart procedure where the heart remains functional. To reiterate, the terms "non-expandable" and "non-collapsible" should not be understood to refer to completely rigid and dimensionally stable, except that the valve is not expandable/collapsible like some proposed minimally invasive or percutaneous delivered valves.

The implantation procedure thus involves first delivering and expanding the base stent 24 at the aortic annulus, and then attaching the valve elements 30 including the valve 34 thereto. Because the valve 34 is not expandable, all of the procedures are typically performed using conventional open-heart techniques. However, because the base stent 24 is delivered and implanted by simple expansion, and then by expansion, the valve element 30 is attached thereto, without sewing, the entire operation takes less time. This hybrid approach will also be easier for surgeons familiar with open-heart procedures and commercially available heart valves.

Moreover, relatively small changes in operation, coupled with the proven use of a heart valve, will result in easier adjustment paths than strictly expandable teleoperation. Even though the system must be validated through clinical testing to meet the FDA pre-market approval (PMA) procedure (as opposed to the 510k submission),acceptance of the valve element 30 will be greatly simplified at least as commercial heart valves, such asAn aortic heart valve.

The prosthetic valve 34 has an expandable attachment mechanism in the form of an attachment stent 36 for securing the valve to the base stent 24. Although attachment brackets 36 are shown, the attachment mechanism may take a variety of different forms, simply eliminating the need for attachment sutures and providing a quick attachment method.

In fig. 5E, the valve element 30 has been advanced to the aortic annulus AA and at the desired implantation location within the base stent 24. The prosthetic valve 34 may include a suture-permeable loop 42, with the loop 42 desirably abutting the aortic annulus AA. More preferably, the sewing ring 42 is positioned above the annulus, or above the narrowest point of the aortic annulus AA, so as to allow selection of a larger aperture than a valve placed within the annulus. With the aforementioned ring expansion, and placement over the ring, using the base stent 24, the surgeon may select a valve having one or two increments larger than previously conceivable. As mentioned, the prosthetic valve 34 is a desired commercially available heart valve having a sewing ring 42. The balloon catheter 32 has been advanced relative to the valve element 30 to replace the nose cone 38 which is not engaged with the attachment stent 36. The inflation balloon 40 on the catheter 30 can be seen just beyond the distal end of the linking scaffold 36.

Fig. 5F shows the balloon 40 on the catheter 32 inflated to expand and deploy the connecting stent 36 adjacent the base stent 24. It is desirable to inflate balloon 40 with a controlled, pressurized sterile saline solution. The connecting stent 36 transitions between its conical contracted state and its generally tubular expanded state. A simple interference between the connecting stent 36 and the base stent 24 may be sufficient to anchor the valve element 30 within the base stent, or interacting shapes such as protrusions, hooks, barbs, fabric, etc.

Because the base stent 24 is expanded prior to attachment of the valve element 30 thereto, a higher strength stent (self-expandable or balloon-expandable) structure may be used. For example, a relatively thick base stent 24 may be used to push the native leaflets apart, and the missing valve elements 30 are not damaged or otherwise adversely affected during high pressure base stent deployment. After deployment of the base stent 24 in the body conduit, the valve element 30 is attached thereto by a deployment attachment stent 36, which may be somewhat lighter and require less expansion force. Likewise, the balloon 40 may have a distal expanded end that is larger than a proximal expanded end so that more force is applied to the connecting stent 36 than to the prosthetic valve 34. In this manner, the prosthetic valve 34 and the flexible leaflets therein are not subjected to high expansion forces from the balloon 40. Indeed, although balloon deployment is shown, the linking stent 36 may also be a self-expanding stent. In the latter configuration, the nose cone 38 is adapted to retain the attachment stent 36 in its contracted state prior to positioning in the flap member 30 within the base stent 24.

As noted above, the base stent described herein can include barbs or other tissue anchors to further secure the stent to tissue, or to secure the connecting stent 36 to the base stent 24. Additionally, the barbs may be deployable (e.g., configured to spread or push radially outward) by expansion of the balloon. Preferably, the attachment stent 36 is covered to promote ingrowth and/or to reduce paravalvular leakage, such as with a dacron tube or the like.

Fig. 5G shows the balloon 40 deflated on the catheter 32 together with the nose cone 38, the nose cone 38 being removed from within the valve element 30. Finally, fig. 5H shows a fully deployed prosthetic heart valve system of the present invention, including valve elements 30 connected to the base stent 24 within the aortic annulus AA.

Fig. 6 is an exploded view and fig. 7 and 8 are assembled views of an exemplary system 50 for delivering a prosthetic heart valve of the present invention. The components of the modified delivery system 50 are also shown in fig. 9 and 10. The delivery system 50 includes a balloon catheter 52 having a balloon at its distal end and a bead hole plug 54 at its proximal end. The bead plug 54 provides a proximal connection 56 that receives a fastener of a luer connector or other such Y-fitting 58. The nose cone 38 described previously may be attached to the distal-most end of the catheter 52, but is more preferably attached to a guidewire (not shown) inserted through the central lumen of the balloon catheter 52.

The catheter 52 and nose cone 38 pass through a hollow handle 60 having a proximal portion 62 and a distal portion 64. The distal end of the distal handle portion 64 is fixedly attached to a sleeve 66 of a valve holder 68, which in turn is attached to the prosthetic heart valve element 30. Details of the valve retainer 68 will be given with reference to fig. 11A-11E.

The two portions 62, 64 of handle 60 are desirably formed of a rigid material, such as molded plastic (molded plastic), and are interconnected to form a relatively rigid and elongated tube for manipulating prosthetic valve element 30 attached to its distal end. In particular, distal portion 64 can be easily connected to retainer sleeve 66, and thus provides a convenient tool for manipulating valve element 30 during the pre-operative flushing step. For this purpose, the distal portion 64 features a distal tubular section 70 connected to the anchor sleeve 66 and an enlarged proximal section 72 having an opening at its proximal end, the proximal section 72 receiving a tubular extension 74 of the proximal handle portion 62. Figure 6 shows an annular washer (O-ring)76 which may be provided on the exterior of the tubular extension 74 for a frictional interference fit to prevent the two parts from disengaging. Although not shown, the distal tubular segment 70 may also have an annular gasket for secure connection to the retainer sleeve 66, or may be threaded or the like. In a preferred embodiment, the balloon 40 on the catheter 52 is packaged within the proximal handle portion 62 for protection and ease of handling. Connecting the proximal and distal handle portions 62, 64 thus "loads" the system 50 such that the balloon catheter 52 can be advanced through the continuous lumen to the valve element 30.

Fig. 9 and 10 illustrate a delivery system 50 similar to that shown in fig. 7, but having an optional connector 77 on the proximal and distal handle portions 62, 64 in the form of a cantilevered tooth that snaps into a complementary recess formed in the respective receiving bore. Similarly, threading on the fitting can be used, as well as other similar expedients. Fig. 9 shows balloon 40 inflated to expand the valve element attached stent 36.

In a preferred embodiment, prosthetic valve element 30 is incorporated into a biological tissue leaflet and packaged and stored, attached to holder 68 but separate from other introduction system 50 elements. Typically, the biological tissue is packaged and stored in canisters with a preservative solution for long shelf life, while the other elements are dry packaged and stored.

When assembled as seen in fig. 7-9, an elongated lumen (not numbered) extends from the proximal end of Y-fitting 58 to the interior of balloon 40. The Y-fitting 58 desirably includes an internally threaded connector 80 for connection to an insufflation system, or a side port 82 with a luer fitting 84, or may be used for insufflation of the balloon 40 using similar expedient.

Fig. 7 and 8 show two longitudinal positions of the catheter 52 and associated structure relative to the handle 60 and associated structure. In the deflated position shown in fig. 7, the balloon 40 is initially positioned within the distal handle portion 64. Fig. 7 illustrates a delivery configuration of the introduction system 50 in which the surgeon advances the prosthetic valve element 30 from the outside to a position adjacent to the target ring. A nose cone 38 extends around and protects the distal end of the conical undeployed linking bracket 36. This configuration is also seen in fig. 5D, although the retainer 68 is removed for cleaning. Note the spacing S between the proximal connection 56 and the proximal end of the handle 60.

As explained above with reference to fig. 5A-5H, the surgeon advances the prosthetic valve element 30 to its desired implantation location at the valve annulus, and then advances the balloon 40 through the valve element and inflates it. To do so, the operator transitions the delivery system 50 from the collapsed configuration of fig. 7 to the deployed configuration of fig. 8, as indicated by arrow 78, with the balloon catheter 40 displaced distally to disengage the nose cone 38 from the linking scaffold 36. Note that the proximal connection 56 now contacts the proximal end of the handle 60, eliminating the distance S indicated in fig. 7.

It should be understood that the prosthetic valve element 30 can be implanted in an annulus with a pre-deployed base stent 24, as described above, or without a base stent 24. The linking stent 36 may be sufficiently strong to anchor the valve element 30 directly proximate the native annulus (leaflet resection or lack thereof) in the absence of the base stent 24. Thus, the description of the system 50 for introducing a prosthetic heart valve should be understood in the context of operation with or without the base stent 24 being pre-deployed.

A more detailed description of the valve element 30 and the valve retainer 68 is necessary before further describing the operation of the delivery system 50. Fig. 11A-11E show various perspective and other views of an exemplary valve element 30 mounted on a delivery holder 68 of the present invention. As mentioned, the valve element 30 includes a prosthetic valve 34 having an attachment stent 36 attached to an inflow end thereof. In a preferred embodiment, the prosthetic valve 34 comprises a commercially available off-the-shelf non-expandable, non-collapsible commercial prosthetic valve. Any number of prosthetic heart valves may be modified to connect with the connecting stent 36 and are therefore suitable for use with the present invention. For example, the prosthetic valve 34 may be a mechanical valve or a valve with flexible leaflets, synthetic or bioprosthetic. However, in a preferred embodiment, the prosthetic valve 34 includes bioprosthetic tissue leaflets 86 (fig. 11A). Further, as described above, it is desirable that the prosthetic valve 34 be a Carpentier-Edwards PERIMOUNT available from Edwards Lifesciences of Irvine, CaliforniaAortic heart valves (e.g., 3000TFX type).

During the manufacturing process, the attachment stent 36 preferably interfaces with the ventricular (or inflow) surface of the valve sewing ring 42, keeping the sewing ring intact to some extent and preventing a reduction in the Effective Orifice Area (EOA) of the valve. Desirably, the connecting stent 36 will be continuously sutured to the sewing ring 42 in a manner that maintains the outer contour of the sewing ring. The sutures may be passed through holes or eyelets in the stent scaffold, or through a fabric covering which is in turn sewn to the scaffold. Other attachment schemes include prongs or hooks that extend inwardly from the bracket, tie bars, Velcro (Velcro), rivet dies, adhesives, and the like. Alternatively, the attachment stent 36 may be more rigidly attached to a rigid element within the prosthetic valve 34. Thus, during implantation, the surgeon may secure the sewing ring 42 in place proximate the ring according to conventional procedures. This gives the surgeon familiarity with tactile feedback to ensure that the correct patient prosthesis fit has been achieved. Moreover, the placement of the sewing ring 42 near the outflow side of the ring helps to reduce the probability of the valve element 30 moving toward the ventricle.

The connecting stent 36 may be a pre-crimped, tapered 316L stainless steel balloon expandable stent, desirably covered by a polyester sleeve 88 to help seal against paravalvular leakage and promote tissue ingrowth once implanted within the base stent 24 (see fig. 5F). The connecting bracket 36 transitions between its tapered, contracted configuration of fig. 11A-11E to its outwardly expanded configuration shown in fig. 5F and also fig. 10.

The connecting bracket 36 desirably includes a plurality of zigzag or otherwise angled, serpentine or web-like rods 90 connected to three generally axially extending struts 92. As will be seen below, the struts 92 desirably feature a series of equally spaced holes to which the polyester sleeve 88, which accommodates sutures in place, can be anchored. When expanded, the stent 36 flares outwardly and engages closely adjacent the inner surface of the base stent 24 and has substantially the same axial length as the base stent, as best seen in fig. 5F. Anchoring means such as barbs or other protrusions from the attachment bracket 36 may be provided to enhance frictional support between the attachment bracket and the base bracket 24.

It should be understood that the specific structure of the connecting stent, whether having straight or curved struts 90, may be modified as desired. There are a variety of stent designs, as described below with reference to fig. 12-17, any of which potentially may be suitable. Also, while the preferred embodiment incorporates a balloon expandable linking stent 36, the self-expanding stent can be replaced with certain modifications, primarily to the delivery system. The same elasticity and design is of course applicable to the base support 24. In a preferred embodiment, it is desirable that the base stent 24 and the connecting stent 36 be plastically expandable to provide a more robust anchor for the valve 34; first to the annulus with or without native leaflets, then between the two stents. The stent may be expanded using a balloon or a mechanical dilator as described below.

Still referring to fig. 11A-11E, the anchor 68 includes the aforementioned proximal hub 66 and its thinner distal extension 94, which forms the central portion of the anchor. Three legs 96a, 96b, 96c circumferentially equally spaced about the central extension 94 and projecting radially outwardly therefrom include an inner strut 98 and an outer engagement shelf 100. The prosthetic valve 34 preferably includes a plurality, typically three, of commissures 102 projecting in the outflow direction. Although not shown, the engagement frame 100 preferably incorporates a recess in which the tip of the engagement point 102 is mounted.

In one embodiment, the anchors 68 are formed of a rigid polymer, such as Delrin or clear polypropylene to increase visibility of the implantation operation. As best seen in fig. 11E, the holder 68 reveals openings between the legs 96a, 96b, 96c to provide the surgeon with good visibility of the valve leaflets 86, the transparency of the legs further facilitating visibility and allowing light to be transmitted therethrough to minimize shadows. Although not described in detail herein, fig. 11E also illustrates a series of through holes in the legs 96a, 96b, 96c, allowing attachment sutures to be guided through the fabric in the prosthetic valve 34 and across the cut in each leg. As is known in the art, cutting the mid-length suture connected to the holder 68 and through the valve allows the holder to be free of valve pull when desired.

Fig. 11C and 11D illustrate a somewhat modified linking bracket 36 from that shown in fig. 11A and 11B, in which struts 90 and axially extending struts 92 are better defined. In particular, the struts 92 are wider and stronger than the struts 90, as the latter provide the stent 36 with the ability to expand from the conical shape shown to a more tubular configuration. Likewise, the generally circular reinforcement ring 104 abuts the valve sewing ring 42. Both the post 92 and the ring 104 further include a series of through holes 106 that can be used to secure the polyester rim 88 to the bracket 36 using sutures or the like. A number of variations of the attachment bracket 36 are also described below.

Fig. 12A-12B illustrate an exemplary attachment stent 36 in a generally expanded shape in a flattened configuration (12A) and a tubular configuration (12B). As mentioned, the web-like struts 90 and the stiffening rings 104 connect the three generally axially extending struts 92. A plurality of evenly spaced holes 106 provide anchors for receiving the polyester sleeve 88 (see fig. 11B) in place. In the illustrated embodiment, the web-like struts 90 further comprise a series of axially extending struts 108. The upper end of the attachment stent 36 attached to the valve sewing ring and defined by the reinforcement ring 104 follows an undulating path of arcuate troughs 110 and peaks 12 alternating. As seen in fig. 11C, the exemplary prosthetic valve 34 has an undulating sewing ring 42 with which the upper end of the connecting stent 36 conforms. In a preferred embodiment, the geometry of the stent 36 matches the geometry of the undulating sewing ring 42. Of course, if the sewing ring of the prosthetic valve is planar, then the upper end of the attachment stent 36 will also be planar. It should also be noted that the tubular version of fig. 12B is illustrative of an expanded configuration, although the balloon 40 may over-expand the free (lower) end of the stent 36 such that it terminates in a slight conical shape.

Fig. 13A and 13B show an alternative attachment stent 120 again in a flattened and tubular configuration, respectively. As with the first embodiment, the connecting stent 120 includes web-like struts 122 extending between a series of axially extending struts 124. In this embodiment, all of the axially extending struts 124 are of substantially the same thin cross-sectional size. The upper or attached end of the stent 120 in turn includes a reinforcing ring 126, although this pattern is interrupted by a series of short lengths separated by gaps. The upper end defines a plurality of alternating valleys 128 and peaks 130, the length of the reinforcement ring 126 defining the peaks. The axially extending struts 124 are in phase with the scalloped shape of the upper end of the stent 120 and coincide with the middle of the peaks and valleys.

The gaps between the lengths that make up the reinforcement ring 126 allow the stent 120 to fit many different sizes of prosthetic valves 34. That is, a majority of the stent 120 is expandable, having a variable diameter, and providing clearance in the reinforcement ring 126 allows the upper end to also have a variable diameter so that it can be shaped to match the size of the corresponding sewing ring. This reduces manufacturing costs, as a correspondingly sized stent need not be used for each different size valve.

Fig. 14 is a plan view of an alternative linking stent 132, very similar to linking stent 120, comprising a web-like strut 134 connected between a series of axially extending struts 136, and defined at its upper end by a stiffening ring 138 formed by a series of short length struts. In contrast to the embodiment of fig. 13A and 13B, the peaks of the upper end of the undulations have opposite gaps as the struts. Another way to express this is that the axially extending struts 136 are out of phase with the scalloped shape of the upper end of the stent 132 and do not coincide with the middle of the peaks and valleys.

Fig. 15 illustrates an exemplary linking bracket 140 also having expandable struts 142 between axially extending struts 144, and an upper stiffening ring 146. The axially extending struts 144 are in phase with the peaks and troughs of the upper end of the stent. The reinforcement ring 146 is cruciform between such rings as described earlier because it is continuous around it but also has a variable diameter. That is, the loop 146 includes a series of struts 148 of fixed length connected by thinner bridge portions 150 of variable length. The bridge portions 150 are each formed with a radius such that they can be straightened (lengthened) or bent (compressed) more. A series of holes 152 are also formed in the upper end of the stent 142 to provide anchoring points for sutures or other attachment means when securing the stent to the sewing ring of a corresponding prosthetic valve.

In fig. 16, an alternative linking scaffold 154 is identical to scaffold 140 of fig. 15, although axially extending struts 156 are out of phase with the peaks and troughs of the undulating upper end.

Fig. 17 shows a still further variation on connecting stent 160 having a series of expandable struts 162 connected by axially extending struts 164. As shown in the version of fig. 12A and 12B, the web-like struts 162 also include a series of axially extending struts 166, although the rods are thinner than the primary axial struts 164. Reinforcing ring 168 is also thicker than web-like struts 162 and features one or more gaps 170 in each trough so that the ring is discontinuous and expandable. Barbs 172,174 on the axially extending struts 164,166 may be used to enhance retention between the linking stent 160 and the base stent, which cooperates with the base stent, or with the annulus tissue in the absence of a base stent, as described above.

As mentioned above, the two-element valve systems described herein utilize an outer or base stent (such as base stent 24) and a valve element having an inner or valve stent (such as connecting stent 36). The valve and its stent are advanced into the lumen of the pre-anchored external stent, and the valve stent expands connecting the two stents and anchoring the valve into its implanted position. It is important that the inner stent and the outer stent are correctly positioned circumferentially and axially to minimize subsequent relative movement between the stents. Indeed, for the primary application of aortic valve replacement, the circumferential location of the valve coaptation is very important relative to the native coaptation. Many variations of attachment stents attached to valve elements are shown and described above. Fig. 18-20 illustrate an exemplary base bracket and the fit between two brackets.

Fig. 18A and 18B show an exemplary embodiment of a base stent 180 that includes a plurality of radially expandable struts 182 extending between a plurality of generally axially extending struts 184. In the illustrated embodiment, the struts 182 form a herringbone pattern between the struts 184, although other configurations such as serpentine or diamond shapes may also be used. The top and bottom rows of radially expandable struts 182 are arranged side-by-side to form a plurality of triangular peaks 186 and valleys 188. The axial struts 184 are in phase with the wave troughs 188.

The plan view of fig. 18A shows four axial projections 190, each extending upwardly from one of the axial struts 184. Although four projections 190 are shown, the exemplary base stent 180 desirably has three evenly circumferentially spaced projections, as seen around the tubular version of fig. 18B, providing positioning indicia for the base stent. These markings thus make it easier for the surgeon to position the bracket 180 so that the markings align with the natural engagement points. In addition, the visible protrusions 190 provide reference marks when the valve element is advanced into the base stent 180 so that the inner stent can be properly positioned within the base stent. In this regard, the projections 190 may be colored differently than the remainder of the stent 180 or have a radiopaque indicator thereon.

The length of the ledge 190 above the top row of intermediate struts 182 may also be graduated to assist the surgeon in axially positioning the stent 180. For example, the distance from the tip of the projection 190 to the natural annulus level can be determined and the projection 190 can be positioned directly below a particular anatomical landmark, such as the level of a coronary ostium.

The wavy dashed line 192 in fig. 18A indicates the upper end of the inner or linking bracket 140, which is shown in the model superimposed on the base bracket 180. As such, the dashed line 192 also represents a wavy sewing ring having a repetition that the sewing ring may be planar, such that the upper end of the attachment stent is also planar. The connecting stent 140 comprises axially extending struts that are in phase with the respective peaks and troughs of the upper end of the stent scallops. In the exemplary combination, the peaks of the upper end of the scalloped connecting struts (dashed lines 192) rotationally correspond (are in phase) with the axial struts 184 having the projections 190. Thus, because the axial struts of the linking stent 140 are in phase with the peaks at their upper ends, they are also in phase with the axial struts 184 of the base stent 180. Conversely, the connecting stent may have axial struts that are out of phase with the peaks at its upper end, in which case the axial struts of each of the two stents are also out of phase.

Fig. 19 shows an alternative base stent 200 having generally the same elements as the base stent 180 of fig. 18A, but with axial struts 184 extending between the outer rows of peaks 186 of the intermediate struts 182. In the earlier embodiment, axial struts 184 extend between wave troughs 188. The linking stent 154 of fig. 16 is shown in a model overlaid on top of the base stent 200 to illustrate how the axial struts of the two stents are now out of phase to increase the link between them.

The stent 200 also shows different rows of intermediate struts 182. Specifically, the first row 202a defines a V having a relatively shallow angle, the second row 202b defines a V having a medium equiangular angle, and the third row 202c defines a V having a more acute angle. The different angles that struts 182 form in these rows when expanded help to form the stent into a conical form. The struts in the third row 202c furthest from the prosthetic valve have the greatest ability to expand to accommodate the conical-to-expanded tubular shape transition of the stent fold.

One skilled in the art will appreciate that there are many ways to increase the retention between the two stents. For example, the peaks and troughs of the mesh-like expandable struts on the two stents may be positioned out of phase or in phase. In a preferred embodiment, the peaks and troughs of the two stents are out of phase so that expansion of the inner stent causes its peaks to deform outwardly into the troughs of the outer stent and thereby provide a linking structure therebetween. The variations described above provide many variations of this fit.

In addition, the axial projections on one or both stents can be bent to provide interference with the other stent (whichever is required to conform to the interference fit). For example, the lower ends of the axial struts 108 in the stent 36 shown in fig. 12A may be bent outward by the expansion of the non-uniformly formed balloon such that they extend within the void within the outer stent. Likewise, the embodiment of fig. 17 illustrates barbs 172, 174 which may be formed to interfere with the respective base stent by bending outward. The transition from one location to another to increase the retained strut ends or barbs between the two stents may be facilitated by mechanical bending, such as with a balloon or by automatic shape change after installation into the body. That is, some shape memory alloys, such as nitinol, may be designed to undergo a shape change after a temperature change such that they assume a first shape at room temperature, and a second shape at body temperature.

Fig. 20 illustrates a simplified arrangement that increases retention between two stents. The inner valve stent 210 fits within the outer base stent 212 such that its lower end 214 extends below the outer stent. Over-expansion of the balloon within the stent 210 causes the lower end 214 to bend or curl outward to prevent relative upward movement of the inner stent within the outer stent.

Fig. 21 is a perspective view of an apparatus 220 for delivering and expanding a base stent 222 within a mechanical dilator 224. In the illustrated embodiment, the dilator 224 includes a plurality of expandable fingers 226 over which the base stent 22 is crimped. The device 220 comprises a syringe-like instrument comprising a barrel 230 in which a plunger (plunger)232 slides linearly. The fingers 226 are axially fixed but are pivotable or retractable relative to the barrel 230. The distal end of the plunger 232 has an outer diameter that is greater than the diameter defined by the inner surface of the expandable fingers 226. There is preferably a proximal lead-in ramp on the inside of the fingers 226 so that distal movement of the plunger 232 progressively cams the fingers outward relative to the barrel 230. Two positions of the plunger 232 are shown in fig. 21 and 23.

Instead of a simple linear movement of the plunger 232, the barrel 230 may be threadably received therein. Further, the plunger 232 may be formed of two parts that freely rotate relative to each other, with the proximal part being threadedly received within the barrel 230 and the distal part not rotating relative to the barrel, with only the fingers 226 being cammed outwardly. Still further, a mechanical linkage may be used instead of a camming action, whereby the hinged together levers produce the outward movement of fingers 226. And still further, hybrid versions using an inflatable balloon with a mechanical portion mounted on the exterior of the balloon may be utilized. Those skilled in the art will appreciate that many variations on this mechanism are possible, with the emphasis being that balloon expansion is not merely a means.

Desirably, the fingers 226 have a shaped profile such that they expand the base stent 222 to better fit the particular shape of the heart valve annulus. For example, the base stent 222 may be expanded into a concave shape with wider superior and inferior ends and a smaller middle portion, and/or the superior end may be tri-lobal to better fit into the aortic sinus. In the latter case, the trilobal shape is useful for positioning the base stent 222 after implantation and for positioning the connecting stent of the valve element received therein.

In another advantageous feature, the two-element valve system illustrated in the foregoing figures provides devices and methods that significantly reduce the time of the surgical procedure compared to replacement valves that are sutured to tissue after removal of the native leaflets. For example, the stent 24 of fig. 5-9 can be quickly deployed and the valve element 30 can also be quickly attached to the stent. This reduces the time required for extracorporeal circulation, thereby significantly reducing the risk to the patient.

In addition to speeding up the implantation process, the present invention has a pre-anchored stent within which the valve and its stent are mounted, allowing the annulus to be expanded to receive a larger valve than would otherwise be possible. In particular, clinical studies have shown that the Left Ventricular Outflow Tract (LVOT) can be significantly expanded and maintain normal function by balloon expandable stents. In this case, "substantially expanded" LVOT means expanded by at least 10%, more preferably between about 10-30%. In absolute terms, the LVOT can be expanded by 1.5-5mm according to the normal pore size. This expansion of the annulus creates the opportunity to increase the size of the surgically implanted prosthetic valve. The present invention utilizes a balloon-expandable base stent, and a balloon-expandable valve stent. The combination of these two stents allows for the expansion of the LVOT at the inflow end of the prosthetic valve at and just below the aortic annulus. The interference fit created between the outside of the base stent and the LVOT secures the valve without a pledget or ensures space occupation, thereby allowing placement of the largest possible valve size. Larger valve sizes will increase volumetric blood flow and reduce pressure gradients through the valve than would otherwise be achieved with conventional surgery.

Those skilled in the art will appreciate that embodiments of the present invention provide important new devices and methods in which a valve can be safely anchored to a body lumen in a quick and efficient manner. Embodiments of the present invention provide a means for implanting a prosthetic valve in a surgical procedure without requiring the surgeon to suture the valve to tissue. Thus, the surgical procedure time is significantly reduced. In addition, in addition to providing a base stent for the valve, the stent may be used to maintain the native valve in an expanded state. Thus, the surgeon does not have to remove the native leaflets, thereby further reducing the procedure time.

It will also be appreciated that the present invention provides an improved system in which valve components can be replaced in a faster and efficient manner. More specifically, it is not necessary to sever any sutures in order to remove the valve. Instead, the valve component can be detached from the stent (or other base stent) and a new valve component attached in the correct position. This is an important advantage when using biological tissue valves or other valves with a limited design life.

While the invention has been described in its preferred embodiments, it is to be understood that the words which have been used are words of description rather than words of limitation. Accordingly, changes may be made within the appended claims without departing from the true scope of the invention.

Claims (29)

1. A prosthetic heart valve system, comprising:

a valve element comprising a non-expandable, non-collapsible prosthetic valve, the valve element further comprising an expandable connecting stent extending from an inflow end thereof, the connecting stent having a collapsed state for delivery to an implantation site and an expanded state configured for outward connection to a heart valve annulus, the connecting stent being continuously sutured to a sewing ring of the prosthetic valve or being rigidly connected to a rigid element within the prosthetic valve, wherein the connecting stent exhibits an inward taper that is conical in a distal direction in the collapsed state and is generally tubular in the expanded state.

2. The system of claim 1, further comprising a base stent adapted to be anchored proximate the heart valve annulus and defining an orifice therein.

3. The system of claim 2, wherein the base stent is expandable and has a contracted state for delivery to an implantation site adjacent a heart valve annulus, and an expanded state sized for contact and anchoring proximate the heart valve annulus.

4. The system of claim 3, wherein the base stent is plastically expandable.

5. The system of claim 1, wherein the connecting stent is plastically expandable.

6. The system of claim 1, wherein the contracted state of the connecting stent is conical, tapering inward in a distal direction.

7. The system of claim 6, wherein the linking scaffold comprises a plurality of radially expandable struts, wherein at least some struts are arranged in rows, wherein a furthest row has a maximum capacity to expand from the collapsed state to the expanded state.

8. The system of claim 1, wherein the connecting stent comprises a plurality of radially expandable struts, and the rows furthest from the prosthetic valve have alternating cusps and depressions.

9. The system of claim 2, wherein the linking stent comprises a plurality of radially expandable struts and the row furthest from the prosthetic valve has alternating cusps and valleys, wherein the base stent comprises holes in which the cusps of the linking stent can protrude to join the two stents.

10. The system of claim 2, wherein the base stent comprises a plurality of radially expandable struts between axially positioned struts, at least some of the axially positioned struts having superior protrusions that differentiate locations around the base stent.

11. A system for delivering and implanting a prosthetic heart valve system, comprising:

a valve element comprising a non-expandable, non-collapsible prosthetic valve, the valve element further comprising an expandable connecting stent extending from an inflow end thereof, the connecting stent having a collapsed state for delivery to an implantation site and an expanded state configured for outward attachment to a heart valve annulus, the connecting stent being continuously sutured to a sewing ring of the prosthetic valve or rigidly attached to a rigid element within the prosthetic valve;

wherein the valve element is configured to be advanced in its contracted state with the connecting stent to an implantation position adjacent the heart valve annulus;

wherein the connecting stent is further configured to expand to the expanded state, contact and connect with the heart valve annulus, and

wherein the connecting scaffold exhibits an inward taper that is conical in a distal direction in the collapsed state and is generally tubular in the expanded state.

12. The system of claim 11, further comprising a base stent adapted to be anchored proximate the heart valve annulus and defining an orifice therein.

13. The system of claim 12, wherein the base stent is plastically expandable, and wherein the expandable base stent is configured to be advanced to the implantation location in a contracted state; and plastically expanding to an expanded state, contacting and anchoring to the heart valve annulus, during which the pore size of the heart valve annulus is increased by at least 10%.

14. The system of claim 11 or 12, wherein the prosthetic valve of the valve element is selected to have an orifice size that matches the increased orifice size of the heart valve annulus.

15. The system of claim 12, wherein the base stent is further configured to be mounted on a mechanical dilator and deployed at the heart valve annulus using the mechanical dilator.

16. The system of claim 11 or 12, wherein the valve element is mounted on a holder having a proximal receptacle and a lumen therethrough, and wherein the holder is mounted on a distal end of a handle having a lumen therethrough, the system further comprising a balloon catheter configured to pass through the handle and the lumen of the holder and within the valve element, and a balloon configured to expand over the balloon catheter to expand the connecting stent.

17. The system of claim 16, wherein the valve element mounted on the holder is packaged separately from the handle and the balloon catheter.

18. The system of claim 16, wherein the contracted state of the linking stent is conical, and wherein the balloon on the balloon catheter has a distal expanded end that is larger than its proximal expanded end, such that the expanded deflection applied to the linking stent is larger than that applied to the prosthetic valve.

19. The system of claim 17, wherein the contracted state of the linking stent is conical, and wherein the linking stent comprises a plurality of radially expandable struts, wherein at least some struts are arranged in rows, wherein the row furthest from the prosthetic valve has the greatest ability to expand from the contracted state to the expanded state.

20. The system of claim 17, wherein the linking scaffold comprises a plurality of radially expandable struts and the row furthest from the prosthetic valve has alternating cusps and valleys, wherein a distal end of the linking scaffold is configured to expand more than the rest of the linking scaffold.

21. The system of claim 12, wherein the base stent and the linking stent have a plurality of radially expandable struts between axially positioned struts, and wherein the linking stent is positioned such that its axially positioned struts are out of phase with those of the base stent to increase retention therebetween.

22. The system of claim 13, wherein the pore size of the heart valve annulus is increased by 1.5-5mm by plastically expanding the base stent.

23. A system for delivering a prosthetic heart valve, comprising:

a valve element comprising a non-expandable, non-collapsible prosthetic valve, the valve element further comprising an expandable connecting stent extending from an inflow end thereof, the connecting stent having a collapsed state for delivery to an implantation site and an expanded state, the connecting stent being continuously sutured to a sewing ring of the prosthetic valve or rigidly connected to a rigid element within the prosthetic valve;

a valve retainer connected to the valve element;

a balloon catheter having a balloon; and

a handle configured to be coupled to the valve holder proximal end and having a lumen for passage of the catheter, the balloon extending distally through the handle, past the holder, and through the valve element,

wherein the connecting scaffold exhibits an inward taper that is conical in a distal direction in the collapsed state and is generally tubular in the expanded state.

24. The system of claim 23, wherein the prosthetic valve comprises a commercially available valve having a sewing ring, and wherein the connecting stent is attached to the sewing ring.

25. The system of claim 23, wherein the contracted state of the connecting stent is conical, tapering inward in a distal direction.

26. The system of claim 23, wherein the collapsed state of the linking stent is conical, tapering inwardly in a distal direction, wherein the balloon catheter further comprises a generally conical nose cone on its distal end that extends through the valve element and engages the distal end of the linking stent in the collapsed state.

27. The system of claim 23, wherein the handle comprises a proximal portion and a distal portion connectable together in series to form a continuous lumen, and wherein the distal portion is adapted to connect to a receptacle of the holder to enable manual manipulation of the valve element using the distal portion prior to connection with the proximal handle portion.

28. The system of claim 27, wherein the balloon catheter and proximal handle portion are packaged with the balloon within the proximal portion lumen.

29. The system of claim 23, wherein the valve element mounted on the holder is packaged separately from the handle and the balloon catheter.