IL304130B2

IL304130B2 - Cardiac anchoring stent, valve system and a method for deploying same

Info

Publication number: IL304130B2
Application number: IL304130A
Authority: IL
Original assignee: Symbiosis C M Ltd
Priority date: 2023-06-28
Filing date: 2023-06-28
Publication date: 2025-04-01
Also published as: WO2025004050A1; IL325612A; IL304130B1; IL304130A

Description

CARDIAC ANCHORING STENT, VALVE SYSTEM AND A METHOD FOR DEPLOYING SAME TECHNOLOGICAL FIELD The present disclosure is concerned with a cardiac valve, a personalized anchoring and sealing mechanism therefor, and a method for deploying and anchoring same.

BACKGROUND ART Cardiac valve replacement may be necessary in cases where the valve is severely damaged or diseased. Replacement of a cardiac valve can often involve complications related with anatomic differences such as variable outlines and borders at the valve site. References considered to be relevant as background to the presently disclosed subject matter are listed below: - WO22201158 - WO20171515- US8,556,8 Acknowledgement of the above references herein is not to be inferred as meaning that these are in any way relevant to the patentability of the presently disclosed subject matter.

BACKGROUND WO22201158 discloses a supporting structure for accommodating a prosthetic valve aimed at replacing valve, a prosthetic valve system, a method for sealing between a native tissue and a prosthetic implant, a kit for implanting a prosthetic valve and a medium to be used with a supporting structure. The technique provides an implant structure with high compatibility with various anatomies while allowing optimal sealing and tissue anchoring, thus implementing personalized valve replacement procedures. This technique provides an accurate fitting for optimal sealing and anchoring to various complex anatomies necessitating a prosthesis. WO2017151566 discloses methods, devices, and systems for anchoring and/or sealing a heart valve prosthesis and, in particular, a mitral valve prosthesis, wherein inflatable elements are used to seal and anchor the mitral valve prosthesis and/or other elements associated with repairing a native mitral valve. US8,556,881 discloses a method of treating a patient with a calcified aortic valve includes introducing a guide wire into a blood vessel. The guide wire is advanced through the aorta to the aortic valve and then through the aortic valve. A balloon dilatation catheter is introduced into the blood vessel over the guide wire. The balloon dilatation catheter includes an elongate body, a distal portion, a guide wire lumen, an inflation lumen, and a dilatation balloon. The balloon dilatation catheter further includes at least one deflection wire lumen, and at least one deflection wire residing in the at least one deflection wire lumen and having a distal end attached to the distal portion. The balloon dilatation catheter is advanced over the guide wire through the aorta, through the aortic valve, and the dilatation balloon is inflated. Acknowledgement of the above references herein is not to be inferred as meaning that these are in any way relevant to the patentability of the presently disclosed subject matter.

GENERAL DESCRIPTION A first aspect of the disclosure is directed to a support structure for supporting a prosthetic cardiac valve, said support structure comprising a flexible tubular stent having an upstream mesh section and a downstream mesh section, with a radially deformable intermediate mesh section extending therebetween, and wherein the upstream mesh section is configured with a plurality of upstream tissue engaging spikes and the downstream mesh section is configured with a plurality of downstream tissue engaging spikes; wherein at an expanded position of the stent said upstream tissue engaging spikes and said downstream tissue engaging spikes project radially outwards from an outside surface of the stent; and an upstream elastic sleeve extending over at least a portion of said upstream mesh section; said upstream elastic sleeve having an upstream inflatable tubular element disposed axially upstream of said upstream mesh section.

The terms ‘upstream’ and ‘downstream’ as used herein in the specification and claims, correspond with normal hemodynamics flow directions, respectively. Accordingly, when considering a Mitral valve blood flows in direction from the upstream left atrium towards the downstream left ventricle; when considering a Tricuspid valve blood flows in direction from the upstream right atrium towards a downstream right ventricle; when discussing the Aortic valve blood flows in direction from the upstream left ventricle towards the downstream aorta, and; and when discussing the Pulmonary valve blood flows in direction from the upstream right ventricle towards the downstream pulmonary artery. The term ‘valve’ as used herein the specification and claims denotes a prosthetic valve engageable within the elastic sleeve, and configurable as a one-way valve, facilitating blood flow in correspondence with hemodynamics flow directions. The prosthetic valve is inherent with a carrier stent, wherein a nominal diameter of the stent of the prosthetic valve, at its deployed position, is greater than a nominal diameter of the stent at its deployed position, hence once deployed, the prosthetic valve is engageable within the elastic sleeve. However, according to another example, the prosthetic valve can be directly secured within the elastic sleeve. The support structure is configurable between a constricted, deploying position at which it is at a closed position, and an expanded, open position at which it assumes a radially expanded position, and wherein at the closed position the upstream tissue engaging spikes and the downstream tissue engaging spikes are coplanar with an outside surface of the stent. Herein the specification and claims, the terms ‘deployed’, ‘expanded’ and ‘nominal’ positions can be used interchangeably, all of which refer to the stent/support structure at a position at which it assumes a maximal diameter. Likewise, the terms ‘un-inflated’ and ‘nominal’ position refer to the stent at its position at rest, prior to manipulating into its deployed position. The support structure, at its closed position, can be received within a deploying catheter. A second aspect of the disclosure is directed to a stent member for supporting a prosthetic cardiac valve, the stent member being a flexible tubular element having an upstream mesh section and a downstream mesh section, with a radially deformable intermediate section extending therebetween, and wherein the upstream mesh section is configured with a plurality of upstream tissue engaging spikes and the downstream mesh section is configured with a plurality of downstream tissue engaging spikes, whereby radially outwardly deforming the upstream mesh portion entails radial outwards deformation of the of upstream tissue engaging spikes, and radially outward deformation of the intermediate section entails radially outwards deformation of the downstream mesh section and of the downstream tissue engaging spikes. Radially outwardly deformation of the upstream mesh portion and of the downstream mesh section is imparted by an inflatable tubular element associated with the respective mesh portion. The stent undergoes thermal treatment, whereby it obtains memory shape, so that once introduced into the body and deformed into its operative, expended position it maintains said memory shape imparted thereto. The stent is a tubular wire mesh, that can be made using different technologies, e.g. weaving a wire, fine cutting techniques through a tubular element and other techniques used in the art of stent manufacturing, depending, among others, on final required mechanical properties. The stent can be made of various biocompatible materials, such as metal (e.g. Nitinol -NiTi), polymeric materials, composite materials and others, however imparting the stent its unique property, namely the ability to be deformed from a closed position and return to its initial expanded shape upon exposure to heat or pressure, or upon cease of a restraint compacting force (in case of a self-expandable device). This allows the stent to be compressed for insertion through a small body incision, and then expand to the desired size and shape once manipulated in site. Before deploying the stent into the body, the tissue engaging spikes remain flush with an outside surface of the stent. However, once the stent is deployed and reaches body temperature (approx. 37C°) the upstream tissue engaging spikes and said downstream tissue engaging spikes project radially outwards from an outside surface of the stent, as per predesigned memory shape thereof. A third aspect of the disclosure is directed to a prosthetic cardiac valve system, comprising: a support structure comprising a flexible tubular stent having an upstream mesh section and a downstream mesh section, with a radially deformable intermediate mesh section extending therebetween, and wherein the upstream mesh section is configured with a plurality of upstream tissue engaging spikes and the downstream mesh section is configured with a plurality of downstream tissue engaging spikes; wherein at an expanded position of the stent said upstream tissue engaging spikes and said downstream tissue engaging spikes project radially outwards from an outside surface of the stent; an upstream elastic sleeve extending over at least a portion of an inside face of said upstream mesh section; said upstream elastic sleeve having an upstream inflatable tubular element disposed axially upstream of said upstream mesh section; and a prosthetic cardiac valve engageable within the upstream elastic sleeve and downstream of the upstream inflatable tubular element, said valve configured to facilitate blood flow therethrough in direction from the upstream mesh section towards the downstream mesh section, corresponding with normal hemodynamics. Notably, the term dock is at times used in the art, as referring to a prosthetic cardiac valve system. According to any of the aspects of the present disclosure, a downstream inflatable tubular element can be configured in association with the downstream mesh section and configured for deploying same radially outwards. The prosthetic cardiac valve system according to the present disclosure can further be configured with an inflating mechanism for inflating and pressure regulating of the pressure within the upstream inflatable tubular element and the downstream inflatable tubular element). The respective inflating mechanism can be independently associated with each of the upstream inflatable tubular element and the downstream inflatable tubular element. A fourth aspect of the disclosure is directed to a prosthetic cardiac valve kit comprising: a support structure comprising a flexible tubular stent having an upstream mesh section and a downstream mesh section, with a radially deformable intermediate mesh section extending therebetween, and wherein the upstream mesh section is configured with a plurality of upstream tissue engaging spikes and the downstream mesh section is configured with a plurality of downstream tissue engaging spikes; wherein at an expanded position of the stent said upstream tissue engaging spikes and said downstream tissue engaging spikes project radially outwards from an outside surface of the stent; upstream elastic sleeve extending over at least a portion of an inside face of said upstream mesh section; said upstream elastic sleeve having an upstream inflatable tubular element disposed axially upstream of said upstream mesh section; a prosthetic cardiac valve engageable within the upstream elastic sleeve and downstream of the upstream inflatable tubular element, said valve configured to facilitate blood flow therethrough in direction from the upstream mesh section towards the downstream mesh section, corresponding with normal hemodynamics; an introducing and deploying system comprising a catheter and a guide wire, said catheter encapsulating the prosthetic cardiac valve system at a collapsed position and configured for deploying the prosthetic cardiac valve system in site; and an inflating mechanism for inflating the upstream tubular element and the downstream inflatable tubular element. A fifth aspect of the disclosure is directed to a method of deploying a prosthetic cardiac valve system as disclosed herein above, the method comprising the following steps: A. Introducing a guide wire with a distal capsule (Over The Wire Delivery system) containing the prosthetic cardiac valve system (‘dock’) at a compressed position, visualized under imaging; B. Exposing the downstream inflatable element with the downstream mesh section of the stent at the sub annular level of the native valve, distal to the native leaflets coaptation line; C. Inflating the downstream inflatable element, while upstream inflatable element is still crimped in the capsule; D. Retrieving the capsule towards the upstream portion of the valve, allowing the downstream spikes to engage downstream of the native valve; E. Unsheathing the upstream inflatable element under imaging; F. Inflating the upstream inflatable element; G. withdrawing the capsule, while the guide wire remains in place; H. Introducing and guiding the compressed prosthetic valve over the guide wire with a dedicated delivery system of the prosthetic valve into the prosthetic cardiac valve system; I. Positioning the prosthetic valve within the inflated prosthetic cardiac valve system under imaging, between the upstream inflatable element and the downstream inflatable element; J. Deploying the prosthetic valve; K. Withdrawing the prosthetic valve’s capsule; L. Adjusting inflation level of the upstream inflatable element and the downstream inflatable element for para-prosthetic leaks elimination, performed under imaging; M. Detaching the inflating mechanism of the upstream inflatable element and the downstream inflatable element; and N. Removing the guide wire. By a specific configuration, there is disclosed a support structure for supporting a prosthetic mitral valve, said support structure having an elastic sleeve member comprising an inflatable supra annular member and an inflatable sub annular member defining therebetween a flow space; and a flexible tubular mesh structure articulated at an outside face of the sleeve, the mesh structure having an atrial section and a ventricular portion, with a radially deformable section extending therebetween, and wherein the ventricular portion is configured with a plurality of sub annular tissue engaging spikes, whereby inflating the sub annular inflatable member entails radially outwards deformation of the downstream deformable section and of the radial deformation of the downstream engaging spikes, wherein a prosthetic valve is secured within the elastic sleeve, at the annular level thereof. According to a particular design, the atrial portion of the mesh is configured with a plurality of supra-annular tissue engaging spikes. According to an embodiment of any of the disclosed aspects, the support structure can further comprise a downstream elastic sleeve extending over at least a portion of an inside face of the intermediate mesh section; said downstream elastic sleeve having a downstream inflatable tubular element axially disposed in overlap over at least an inside portion of the intermediate mesh section and the portion of the downstream mesh section. The support structure is configured for positioning and securing within a cardiac valve cavity wherein at its deployed, expanded position the upstream inflatable tubular element is configured for bearing over the annulus of the native cardiac valve, to thereby seal and prevent blood flow external to the sleeve.

Once the support structure is positioned and secured within a cardiac valve cavity, the stent is allowed to assume its expanded shape and bears against the native commissure, wherein the inflated upstream inflatable tubular element bears over the annulus of the native cardiac valve, and functions as a seal to prevent blood flow external to the sleeve. The upstream mesh section and a downstream mesh section define between them a flow path in direction from the downstream mesh section to the upstream mesh section, in correspondence with normal hemodynamics, wherein a prosthetic valve is engageable within the elastic sleeve along said flow path. A prosthetic cardiac valve is securable within the stent, said cardiac valve configurable for blood flow administration along the flow path, in direction from the upstream mesh section to the downstream mesh section in direction corresponding with normal hemodynamics. A temporary valve is configurable between the upstream and downstream mesh section at a non-deformable section of the support structure, for temporarily regulating blood flow, in the direction corresponding with the normal hemodynamics, during a procedure of positioning and deploying the support structure, whereby upon positioning and deploying the prosthetic valve within the support structure, said temporary valve is over-ridden by the prosthetic valve. Any one or more of the following features, designs and configurations can be associated with any one or more of the aspects of the present disclosure, individually or in various combinations thereof: • The upstream tissue engaging spikes and the downstream tissue engaging spikes face towards an upstream side of the stent; • The intermediate mesh section can be configured as an undulating/serpentining section, axially extending between the upstream mesh section and the downstream mesh section; • the intermediate section can be configured as axially extending posts or segments having a polygonal shape; • The intermediate mesh section integrally extends with the upstream mesh section and the downstream mesh section: • The upstream mesh section can extend in proximity below the downstream inflatable tubular element; • The upstream inflatable tubular element can extend opposite at least a portion of the intermediate mesh section and a portion of the downstream mesh section; • The stent can be cylindrical and however is sufficiently elastic to assume a shape of the respective cardiac valve cavity into which it is applied; • The upstream elastic sleeve and the downstream elastic sleeve can be a homogeneous sleeve or independent sleeves; • The sleeve member can be a continuous sleeve member comprising an intermediate portion extending between the upstream elastic sleeve and the downstream elastic sleeve; • At its deployed, expanded position, the stent can have a frustoconical shape wherein a narrow portion thereof is the upstream section of the stent; • The projecting spikes can have a pointed end facing the upstream end of the stent; • The projecting spikes can be equally distributed about a perimeter of the stent; • The projecting spikes can have a triangle/ teardrop shape; • The inflatable tubular upstream element can be disposed within an annular pouch of the sleeve; • The support structure is configurable for use as a cardiac valve support for any one of the Mitral valve, the Aortic valve, the Tricuspid valve and the Pulmonary valve. • The arrangement is such that at a deployed position, when the upstream inflatable tubular element is inflated, it serves as an annular seal disposed upstream of the prosthetic cardiac valve, seal to restrict blood flow only through said prosthetic cardiac valve; • The support structure is a valve support for a prosthetic Mitral valve, wherein the upstream inflatable tubular element is configurable for supra-annular positioning and inflating, within the left atrium; • The support structure is a valve support for a prosthetic Aortic valve, wherein the upstream inflatable tubular element is configurable for sub-annular inflation; • The support structure is configurable for use as a valve support for a prosthetic Tricuspid valve, wherein the upstream inflatable tubular element is configurable for supra-annular positioning and inflating, within the right atrium; • The support structure is configurable for use as a valve support for a prosthetic Pulmonary valve, wherein the upstream inflatable tubular element is configurable for sub-annular inflation; • At an initial, unstressed position, the stent be cylindric; • The stent can be secured at an inside face of the flexible sleeve; • The sleeve member can be made of any stretchable, biocompatible material, such as fabrics, polymeric sheets, metal sheet, etc.; • The upstream inflatable tubular element and the downstream inflatable tubular element can each be configured as an annular pocket of the sleeve, accommodating an inflatable annular balloon; • Each of the upstream inflatable tubular element and the downstream inflatable tubular element can be configured with a one-way inflating valve; • The prosthetic cardiac valve kit can further comprise a detachable inflation tube detachably articulated with each of the upstream inflatable tubular element and the downstream inflatable tubular element; • Each of the upstream inflatable tubular element and the downstream inflatable tubular element can be configured with an inflation valve, to which an inflation tube is detachably attachable to; • One or both of the stent and the elastic sleeve and the prosthetic cardiac valve can be drug-eluting; • The prosthetic cardiac valve is anchorable to the upstream mesh section or to the upstream elastic sleeve; • The upstream inflatable tubular element and the downstream inflatable tubular element can be received within an enveloping portion of the upstream elastic sleeve and the downstream elastic sleeve, respectively. • Each of the upstream inflatable tubular element and the downstream inflatable tubular element can comprise an inflation/deflation valve; • The inflation/deflation valve can be detachable; • The upstream inflatable tubular element and the downstream inflatable tubular element can be inflated by a compressed inflation fluid; • The compressed inflation fluid can be a gaseous substance; • The compressed inflation fluid can be a liquid; • The compressed inflation fluid can be a liquid comprising a puncture sealing agent; • At an inflated state the upstream inflatable tubular element extends radially beyond the free tips of the stent. • The upstream elastic sleeve can be secured to an inside face of stent, or to an outside face thereof; • The downstream elastic sleeve can be secured to an inside face of stent, or to an outside face thereof.

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Fig. 1A is perspective view of a stent used in conjunction with a prosthetic cardiac valve support structure, according to an aspect of the disclosure, the stent at an un-deformed position; Fig. 1B is a side view of Fig. 1A; Fig. 1C is a top view of Fig. 1B; Fig. 1Dis a flattened planar view of the deformable intermediate mesh section of the stent at a manufacturing position, before compressing; Fig. 1E is an enlarged view of the portion marked I in Fig. 1B; Fig. 2A is a perspective view of the stent of Fig. 1A, illustrated at a deployed/expanded position; Fig. 2Bis a side view of Fig. 2A; Fig. 2C is a top view of Fig. 2B; Fig. 2D is an enlarged view of the portion marked II in Fig. 2B; 30 Fig. 3A is a perspective view illustrating an embodiment of prosthetic cardiac valve support structure, comprising an upstream flexible sleeve, the support structure at a deployed position, however with the inflatable tubular element deflated; Fig. 3Billustrates the prosthetic cardiac valve support structure of Fig. 3A at a deployed/expanded position, upon inflating the upstream inflatable tubular element; Fig. 4A is a perspective view illustrating another embodiment of prosthetic cardiac valve support structure, comprising an upstream flexible sleeve and a separate, downstream flexible sleeve, the support structure at a closed position, however with the inflatable tubular elements deflated; Fig. 4B illustrates the prosthetic cardiac valve support structure of Fig. 4A at a deployed/expanded position, upon inflating both the inflatable tubular elements; Fig. 5A is a perspective view illustrating an embodiment of prosthetic cardiac valve support structure, comprising an upstream flexible sleeve and an integrated, downstream flexible sleeve, the support illustrated prior to inflating the inflatable tubular elements, however with the inflatable tubular elements deflated; Fig. 5B illustrates the prosthetic cardiac valve support structure of Fig. 5A at a deployed/expanded position, upon inflating both the inflatable tubular elements; Fig. 5C is a longitudinal section along line 5C – 5C in Fig. 5B; Fig. 6Ais a side view illustrating only the stent used in the embodiment of Fig. 5B; Fig. 6B is a top view of the stent of Fig. 6A; Fig. 7A is a top view of the prosthetic cardiac valve support structure of Fig. 5B; Fig. 7B is a bottom view of the prosthetic cardiac valve support structure of Fig. 5B; Fig. 7Cis an exploded view of a support structure and a prosthetic cardiac valve for use in conjunction therewith, constituting together a prosthetic cardiac valve system; Fig. 7D is a sectioned view through a prosthetic cardiac valve system at a deployed position; Fig. 7E illustrates the prosthetic cardiac valve system deployed within a human heart as a mitral valve; Fig. 8A illustrates a heart implanted with a Mitral prosthetic cardiac valve support structure and a Tricuspid prosthetic cardiac valve support structure, according to an example of the disclosure; Fig. 8B illustrates a prosthetic cardiac valve support structure according to an example of the disclosure, configured as a Pulmonary valve; Fig. 8C illustrates a prosthetic cardiac valve support structure according to an example of the disclosure, configured as an Aortic valve; Fig. 8D is an enlarged view of the portion marked 8D in Fig. 8C; Fig. 9 is a flowchart of a method for deploying a prosthetic cardiac valve according to an embodiment of the disclosure, referring to steps A to N of the disclosed method; Figs. 10A to 10E illustrate steps of deploying and positioning the prosthetic cardiac valve support structure according to the flow chart of Fig. 9, wherein; Fig. 10Aillustrates the prosthetic cardiac valve system at a crimped position, over the guide wire; Fig. 10Billustrates the device of Fig. 10A upon exposing the downstream inflatable element; Fig. 10C illustrates the device of Fig. 10A upon inflating the downstream inflatable element; Fig. 10D illustrates the device of Fig. 10C from a proximal end; Fig. 10E illustrates the device of Fig. 10C from a distal end; Fig. 11Aillustrates the transeptal approach to the mitral valve of a heart, with the prosthetic cardiac valve system over the guide wire (Fig. 10A), at a crimped, delivery position; Fig. 11Billustrates positioning the delivery system tip sub annularly e; Fig. 11Cillustrates the system upon exposing the downstream inflatable element (Fig. 10B); Fig. 11Dillustrates the system upon inflating the downstream inflatable element (Fig. 10C – 10E); Fig. 11Eillustrates the system with the inflated downstream balloon being pulled back with guide wire towards the annulus for anchoring by via stent’s spikes grasping the native valve’s leaflets; Fig. 11F illustrates the upstream inflatable member deployed at its nominal size in location, prior to inflation; Fig. 11G illustrates the upstream inflatable member positioned and while the inflation process ; and Fig. 11H illustrates the system at a deployed, operative position.

DETAILED DESCRIPTION OF EMBODIMENTS Attention is now made to the drawings, for better understanding the disclosure. In Figs. 1A to 1E there is illustrated a stent member generally designated 10 , configured for supporting a prosthetic cardiac valve, as will be disclosed herein after in detail. In Figs. 1A – 1E the stent member 10 is at an un-deformed position, i.e. after cutting. The stent member 10 is a tubular cylindrical wire/mesh-like element, which in the illustrated example is cut out of a cylindrical body, however, a stent can be made using different technologies, e.g. weaving a wire, fine cutting techniques through a tubular element and other techniques used in the art of stent manufacturing, depending, among others, on final required mechanical properties. The stent undergoes thermal treatment, whereby it obtains memory shape, so that once introduced into the body and deformed into its operative, expended/nominal position. it maintains said memory shape imparted thereto. The stent is made of various biocompatible materials, such as metal (e.g. Nitinol -NiTi), polymeric materials, composite materials and others, however imparting the stent its unique property, namely the ability to be deformed from a closed position and return to its initial expanded shape upon exposure to heat or pressure, or upon cease of a restraint compacting force (in case of a self-expandable device). This allows the stent to be compressed for insertion through a small body incision, and then expand to the desired size and shape once manipulated in site. The stent 10 is a flexible tubular element having an upstream mesh section 12 and a downstream mesh section 14 , defining between them a flow path F in direction from the upstream mesh section 12 to the downstream mesh section 14 , in correspondence with normal hemodynamics. It is to be noted that the terms ‘upstream’ and ‘downstream’ as used herein in the specification and claims, correspond with normal hemodynamics flow directions, respectively. Accordingly, when considering a Mitral valve blood flows in direction from the upstream left atrium towards the downstream left ventricle; when considering a Tricuspid valve blood flows in direction from the upstream right atrium towards a downstream right ventricle; when discussing the Aortic valve blood flows in direction from the upstream left ventricle towards the downstream aorta, and; and when discussing the Pulmonary valve blood flows in direction from the upstream right ventricle towards the downstream pulmonary artery. The stent 10 is further configured with a radially deformable intermediate section 18 extending between the upstream mesh section 12 and the downstream mesh section 14 , and wherein the upstream mesh section 12 is configured with a plurality of upstream tissue engaging spikes 20 facing upstream, and the downstream mesh section 14 is configured with a plurality of downstream tissue engaging spikes 22also facing upstream. The upstream tissue engaging spikes 20 and the downstream tissue engaging spikes 22 are triangular/teardrop shaped having a pointed tip, wherein at an initial state (i.e. prior to exposure to predetermined temperature of 37°C) said spikes 20 and 22 extend coplanar with an outside surface of the stent, i.e. do not radially project from an outside face 25 (Fig. 1C) of the stent 10. However, once introduced in situ, and as the stent reaches the predetermined temperature of 37°C – said upstream tissue engaging spikes 20 and downstream tissue engaging spikes 22 deform to their memory shape projecting radially outwards from the outside face of the stent . The spikes 20, 22 are configured for projecting into tissue of the native cardiac valve, for securing thereto a prosthetic cardiac valve system, as will be discussed. The free tips (ends) 26 , 28 of the stent 10 , at both respective axial ends thereof, are rounded, and said tips are also coplanar with the outside face 25 of the stent 10 . The intermediate section 18 connects between the upstream mesh section 12 and the downstream mesh section 14 , and has an undulating pattern 19 , imparting it flexibility for radially deforming so as to bear against inside walls of the native commissure (as will be discussed herein below). However, it is appreciated that the undulating pattern of the intermediate section 18 is a mere example and other design options are possible. For example, the intermediate section 18 can be configured as axially extending posits or segments having a polygonal shape. Further attention is directed also to Figs. 2A to 2D of the drawings, illustrating the stent 10 after it has been allowed to deform under thermal properties. Namely, pre-deploying the stent into the body (Figs. 1A – 1E), the tissue engaging spikes remain flush with an outside surface of the stent. However, once the stent is deployed and reaches body temperature (approx. 37C°) the upstream tissue engaging spikes and said downstream tissue engaging spikes project radially outwards from the outside surface of the stent, as per predesigned memory shape thereof. It is noted that the axial length of the stent 10 decreases, as it radially expands, and significantly wherein the upstream tissue engaging spikes 20 and the downstream tissue engaging spikes 22 now project radially outwards, i.e. project from the outside face 25 of the stent 10 (Fig. 2C). With further attention being made now also to Figs. 3A and 3B, there is illustrated an example of a prosthetic cardiac valve system 50 , according to an aspect of the disclosure. The prosthetic cardiac valve system 50 comprises a stent 10 of the kind disclosed hereinbefore, and wherein an upstream elastic sleeve 54 having a tubular section 56 extends over at least a portion of an inside face 27 of said upstream mesh section 12 , and secured thereto, e.g. by adhering, welding, stitching, etc. The sleeve member 54 can be made of any stretchable, biocompatible material, such as fabrics, polymeric sheets, metal sheet, etc. The upstream elastic sleeve 54 comprises an upstream inflatable tubular element 60 disposed axially beyond the free tips 26 of the stent, namely axially upstream of said upstream mesh section 12 , wherein the upstream inflatable tubular element 60 is a fluid-tight annular portion of the sleeve 54 , or it can be an inflatable bladder received within a pocket of the sleeve. The upstream inflatable tubular element 60is configured with an inflating mechanism (e.g. tubing 64 ) for inflating and pressure regulating of the pressure within the upstream inflatable tubular element 60 . The tubing 64 can be detachable from the inflatable tubular element with a suitable valve 66 (Fig. 3A) provided. The inflatable tubular element 60 can be inflated by any inflating agent (gas or liquids), and a puncture sealing agent can be applied to the inflating agent. It is noted that the diameter of the inflated upstream inflatable tubular element 60is greater than that of the prosthetic cardiac valve system 50at its deployed position. As can be noted in Figs. 7A and 7B, the prosthetic cardiac valve system 50 comprises a unidirectional prosthetic cardiac valve 70 (secured within the upstream elastic sleeve however downstream of the upstream inflatable tubular element 60 ). The valve is configured to facilitate blood flow therethrough in direction of the flow path F (namely from the upstream mesh section 12 towards the downstream mesh section 14 ), corresponding with normal hemodynamics. It is appreciated that the prosthetic cardiac valve 70 can be a leaf-type valve as illustrated in the drawings, or any other type. In Fig. 3A the upstream inflatable tubular element 60 is deflated, whilst the upstream tissue engaging spikes 20 and the downstream tissue engaging spikes 22are at their radially outwards deformed position, however with the stent 10 still at a cylindrical, undeformed state. Once the upstream inflatable tubular element 60 is inflated (Fig. 3B), it assumes an overall radii greater than that of the stent and the associated sleeve, hence it will bear over the annulus of the native cardiac valve (Fig. 8A), thereby sealing the valve external vicinity, i.e. preventing blood flow external to the sleeve so that blood flow takes place through the flow path F (through the valve). Figs. 4A and 4B illustrate a modification of the embodiment illustrated in Figs. 3A and 3B. A prosthetic cardiac valve system 70 , according to an aspect of the disclosure comprises a stent 10 of the kind disclosed hereinbefore, and wherein an upstream elastic sleeve 74 having a tubular section 76 extends over at least a portion of an inside face 27 of said upstream mesh section 12 , and secured thereto as discussed hereinabove. The sleeve member 74 can be made of any stretchable, biocompatible material, such as fabrics, polymeric sheets, metal sheet, etc. Similar to the arrangement of Fig. 3A, the upstream elastic sleeve 74 comprises an upstream inflatable tubular element 80 disposed axially beyond the free tips 26 of the stent, wherein the upstream inflatable tubular element 80 is a fluid-tight annular portion of the sleeve 74(or it can be an inflatable bladder received within a pocket of the sleeve, as discussed herein before). The upstream inflatable tubular element 80is configured with an inflating mechanism (e.g. tubing 84 ) for inflating and pressure regulating of the pressure within the upstream inflatable tubular element 80 . Tubing 84 can be detachable from the inflatable tubular element with a suitable valve 86 (Fig. 3A) provided. The inflatable tubular element 80 can be inflated by any inflating agent (gas or liquids), and a puncture sealing agent can be applied to the inflating agent. Once inflated, the upstream inflatable tubular element 80 extends radially beyond the free tips 26 of the stent, to thereby assume a sealing position over the annulus of the native cardiac valve. The prosthetic cardiac valve system 70 comprises a unidirectional prosthetic cardiac valve V (Figs. 7A and 7B), similar to the disclosure in connection with Figs. 3A and 3B herein before.

Unlike the embodiment of Figs. 3A and 3B, the prosthetic cardiac valve system 70 further comprises a downstream elastic sleeve 94 , made of any stretchable, biocompatible material, such as fabrics, polymeric sheets, metal sheet, etc. Downstream elastic sleeve 94 has a sleeve portion 96 secured (e.g. by adhering, welding, stitching, etc.) to an inside face 27 of the downstream mesh section 14. Downstream elastic sleeve 94 is further configured with a downstream inflatable tubular element 100 disposed axially behind, i.e. upstream of the free tips 28 of the stent 10 . The downstream inflatable tubular element 100 is a fluid-tight annular portion of the sleeve 94 , or it can be an inflatable bladder received within a pocket of the sleeve. The downstream inflatable tubular element 100 is configured with an inflating mechanism ( 102 ) for inflating and pressure regulating of the pressure within the downstream inflatable tubular element 100 . The inflating arrangement can be common with the upstream inflatable tubular element 80 , for simultaneous inflation thereof, or each of the inflatable tubular element 80 and 100 can be fitted with an individual inflating arrangement. As mentioned before, the inflating mechanism can be detachable from the inflatable tubular element with a suitable valve 86 (Fig. 3A) provided and the inflation can take place by any inflating agent (gas or liquids), and a puncture sealing agent can be applied to the inflating agent. In Fig. 4A the prosthetic cardiac valve system 70 is illustrated at an un-inflated, nominal stent position, wherein the upstream inflatable tubular element 80 and the downstream inflatable tubular element 100 are deflated, however with the upstream tissue engaging spikes 20 and the downstream tissue engaging spikes 22 of the stent disposed into the radially outwardly projecting position. This is the position upon introducing the prosthetic cardiac valve system 70and positioning same within the native cardiac valve. The arrangement is such that radially outwardly deforming the upstream mesh portion and the downstream mesh section will increase respective engagement of the radial outwards projecting upstream tissue engaging spikes and of the downstream tissue engaging spikes, wherein, as formerly explained, the tissue engaging spikes deform to project radially outwards from the outside surface of the stent, upon reaching the predefined temperature, as per predesigned memory shape thereof. Accordingly, upon inflating the upstream inflatable tubular element 80 and the downstream inflatable tubular element 100 (Fig. 4B), the prosthetic cardiac valve system 70 becomes arrested within the native cardiac valve, wherein the upstream inflatable tubular element 80 will bear over the annulus of the native cardiac valve (Fig. 8A), thereby sealing the valve external vicinity, i.e. preventing blood flow external to the sleeve so that blood flow takes place through the flow path F (through the valve), and wherein the downstream inflatable tubular element 100 applies radial force on the downstream mesh section 14 , resulting in outward deformation of the downstream mesh section 14 . Yet an embodiment of the disclosure is disclosed with reference to Figs. 5A and 5B). In fact, the prosthetic cardiac valve system 120 illustrated in Figs. 5A and 5B is similar to the embodiment of Figs. 4A and 4B, in that it too comprises an upstream elastic sleeve 122 with an upstream inflatable tubular element 124 , and a downstream elastic sleeve 130 downstream inflatable tubular element 132 . However, a distinguishing difference between the embodiments resides in that the upstream elastic sleeve 122 is integral (or integrated, e.g. by stitching, welding adhering, etc.) with the downstream elastic sleeve 130 , through coextending tubular section 126 and sleeve portion 134 . The upstream inflatable tubular element 124 and the downstream inflatable tubular element 132can be simultaneously inflated, or independently of one another, as mentioned hereinbefore. The arrangement is such that deploying the system into the heart and upon reaching the nominal temperature of 37C° the upstream tissue engaging spikes 20 , and the downstream tissue engaging spikes 22 deform into radial projection from the external face of the stent, and wherein inflation of the inflatable tubular elements results in deformation of the upstream mesh portion 12 and the downstream mesh portion 14 , entailing outward deformation of the intermediate section 18 , wherein the support structure securely bears against native heart tissue. Accordingly, upon inflating the upstream inflatable tubular element 124 and the downstream inflatable tubular element 132 (Fig. 5B), the prosthetic cardiac valve system 120 becomes arrested within the native cardiac valve, wherein the upstream inflatable tubular element 124 will bear over the annulus of the native cardiac valve (Fig. 8A), thereby sealing the valve external vicinity, i.e. preventing blood flow external to the sleeve so that blood flow takes place through the flow path F (through the valve), and wherein the downstream inflatable tubular element 132 applies radial force on the downstream mesh section 14 , resulting in outward deformation of the downstream mesh section 14 .

In Figs. 6A and 6B the stent 10 is isolated from other elements of the prosthetic cardiac valve system, however after it has been deformed into its expanded position, having a frustoconical shape, as explained hereinabove, with the upstream tissue engaging spikes 20 and the downstream tissue engaging spikes 22at their radially outwards deformed position. Figs 7C to 7E illustrate in further detail a prosthetic cardiac valve system according to the disclosure, generally designated 140 . In Fig. 7C there is illustrated a prosthetic valve generally designated 141 , of known design, comprising a set of valve leaflets 142 secured within a stent cage 143 . A nominal diameter Dnv of the prosthetic valve 141 is slightly greater than a nominal diameter Dns of the support structure generally designated 145 . The arrangement is such that once the prosthetic valve 141is deployed within the deployed support structure 145 , the prosthetic valve 141 is engaged there within (Fig. 7D). in the superimposed image of Fig. 7D the prosthetic valve is represented by thickened dashed lines. Fig. 7E illustrates a prosthetic cardiac valve system 140 deployed within a human heart H as a mitral valve. Whilst hard to note in the drawings, it can be seen, best in Fig. 7D, that the support structure 145 is further configured with a set of temporary valve leaflets 148positioned between the upstream and downstream mesh section at a non-deformable section of the support structure, said temporary valve leaflets 148 configured for temporarily regulating blood flow, in the flow direction F (corresponding with the normal hemodynamics), during a procedure of positioning and deploying the support structure 145 and until the prosthetic valve 141 is positioned and abhorred within the support structure 145 , whereby upon positioning and deploying the prosthetic valve , said temporary valve leaflets 148 is over-ridden by the stent cage 143 of the prosthetic valve. Figs. 8A – 8C exemplify use of a prosthetic cardiac valve system according to the disclosure, at the different native valves in a human heart H. In Fig. 8A a first prosthetic cardiac valve system 150 is fitted at the Mitral valve of heart H , and wherein arrow F illustrates the flow path in a normal hemodynamics flow direction, from the upstream left atrium LA towards the downstream left ventricle LV , and wherein the upstream inflatable tubular element 152 is inflated with the left atrium LA at a sealing position. Also seen in Fig. 8A, a second prosthetic cardiac valve system 160 is fitted at the Tricuspid valve of heart H , and wherein arrow F illustrates the flow path in a normal hemodynamics flow direction, from the upstream right atrium RA towards the downstream right ventricle RV , and wherein the upstream inflatable tubular element 162 is inflated with the right atrium RA at a sealing position. In Fig. 8B a prosthetic cardiac valve system 170 is fitted at the pulmonary valve of heart H , and wherein arrow F illustrates the flow path in a normal hemodynamics flow direction, from the upstream right ventricle RV towards the downstream pulmonary artery PA , and wherein the upstream inflatable tubular element 172 is inflated sub annularly at a sealing position. In Figs. 8C and 8D a prosthetic cardiac valve system 180 is fitted at the aortic valve of the heart H , and wherein arrow F illustrates the flow path in a normal hemodynamics flow direction, from the upstream left ventricle LV towards the downstream aorta AO , and wherein the upstream inflatable tubular element 182 is inflated sub annularly at a sealing position. Turning now to Figs. 9, 10A to 10E and 11A to 11H of the drawings, there is described a method of deploying the prosthetic cardiac valve system 120 according to an example of the present disclosure, the method comprising the following steps (step numbering corresponding with levels in Fig. 9): A. Introducing an assembly 190 over a guide wire 191 received within a lumen 192 with a distal capsule 194 (Over The Wire Delivery system) containing the prosthetic cardiac valve system 120 (‘dock’) at a compressed position (Figs. 10A, 11A, 11B), visualized under imaging; B. Exposing the downstream inflatable element 132 with the downstream mesh section 14 of the stent at the sub annular level of the native valve, distal to the native leaflets coaptation line (Figs. 10B, 11C); C. Inflating the downstream inflatable element 132 (Figs. 10C - 10E and 11D), while upstream inflatable element 124 is still crimped in the capsule; D. Retrieving the capsule 194 towards the upstream portion of the valve, allowing the downstream spikes 22 to engage the sub annular apparatus of the native valve (Fig11E); E. Unsheathing the upstream inflatable element 124 under imaging (Fig. 11F); F. Inflating the upstream inflatable element 124 (Fig. 11G); G. withdrawing the capsule 194 , while the guide wire 191 remains in place (Fig. 11H); H. Introducing and guiding the compressed prosthetic valve over the guide wire 191 with a dedicated delivery system of the prosthetic valve into the prosthetic cardiac valve system 120 ; I. Positioning the prosthetic valve within the inflated prosthetic cardiac valve system under imaging, between the upstream inflatable element and the downstream inflatable element; J. Deploying the prosthetic valve; K. Withdrawing the prosthetic valve’s capsule; L. Adjusting inflation level of the upstream inflatable element and the downstream inflatable element for para-prosthetic leaks elimination, performed under echo guidance; M. Detaching the inflating mechanism 64 of the upstream inflatable element and the downstream inflatable element; and N. Removing the guide wire 191 . 15

Claims

304130/ - 23 - CLAIMS:

1. A prosthetic cardiac valve system, comprising: a stent comprising a flexible tubular element having an upstream mesh section, a downstream mesh section, and a radially deformable intermediate section extending therebetween, wherein the upstream mesh section is configured with a plurality of upstream tissue engaging spikes, and the downstream mesh section is configured with a plurality of downstream tissue engaging spikes; wherein said upstream tissue engaging spikes and said downstream tissue engaging spikes are made of memory shape material and are configured, at a closed position to be coplanar with an outside surface of the stent, and at an expanded deployed position of the stent, after being introduced in situ and reaching a predefined temperature to deform to their memory shape to project radially outwards from an outside surface of the stent to their radially outwards deformed position; an upstream elastic sleeve extending over at least a portion of said upstream mesh section, said upstream elastic sleeve having an upstream inflatable tubular element disposed axially upstream of said upstream mesh section; and a prosthetic cardiac valve configured to be secured within the upstream elastic sleeve after said stent is positioned in situ and the upstream inflatable tubular element of said upstream elastic sleeve is inflated.

2. The prosthetic cardiac valve system of claim 1, wherein the stent is configured for positioning and securing within a cardiac valve cavity, wherein at its deployed, expanded position the upstream inflatable tubular element is configured for bearing over the annulus of a native cardiac valve, to thereby seal and prevent blood flow external to the sleeve.

3. The prosthetic cardiac valve system of claim 1 or claim 2, wherein the stent is configurable for positioning and securing within a cardiac valve cavity, and wherein when the stent assumes its expanded shape and bears against the native annulus, the inflated upstream inflatable tubular element bears over the annulus of a native cardiac valve, and functions as a seal to prevent blood flow external to the sleeve.

4. The prosthetic cardiac valve system of claim 2, wherein at the deployed position, when the upstream inflatable tubular element is inflated, it serves as an annular seal disposed radially, surrounding the prosthetic cardiac valve, to restrict blood flow only through said prosthetic cardiac valve. 304130/ - 24 -

5. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the upstream mesh section and a downstream mesh section define between them a flow path in direction from the upstream mesh section to the downstream mesh section, in correspondence with normal hemodynamics.

6. The prosthetic cardiac valve system according to any one of the preceding claims, wherein a prosthetic cardiac valve is secured within the upstream mesh section of the stent, said cardiac valve being configured and operable for blood flow administration along the flow path, in direction from the upstream mesh section to the downstream mesh section in direction corresponding with normal hemodynamics.

7. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the stent further comprises a downstream elastic sleeve extending over at least a portion of an inside face of the intermediate mesh section, said downstream elastic sleeve having a downstream inflatable tubular element axially and radially disposed in overlap over at least an inside portion of the intermediate mesh section and the portion of the downstream mesh section.

8. The prosthetic cardiac valve system of claim 7, wherein the upstream elastic sleeve and the downstream elastic sleeve are a homogeneous sleeve or independent sleeves.

9. The prosthetic cardiac valve system of claim 7, wherein each of the upstream elastic sleeve and the downstream elastic sleeve are secured to either an inside face of stent, or to an outside face thereof.

10. The prosthetic cardiac valve system of claim 7, wherein the sleeve member is a continuous sleeve member comprising an intermediate portion extending between the upstream elastic sleeve and the downstream elastic sleeve.

11. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the inflatable tubular element is configured with an inflating mechanism for inflating and pressure regulating of the volume and pressure within the inflatable tubular element.

12. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the inflatable tubular element is associated with an inflation/deflation port.

13. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the inflatable tubular element is disposed within an annular pouch of the sleeve. 304130/ - 25 -

14. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the inflatable tubular element is inflatable with a fluid comprising a puncture sealing agent.

15. The prosthetic cardiac valve system according to any one of claims 7 to 14, wherein the upstream inflatable tubular element and the downstream inflatable tubular element are received within an enveloping portion of the upstream elastic sleeve and a downstream elastic sleeve, respectively.

16. The prosthetic cardiac valve system according to any one of claims 7 to 15, wherein the upstream inflatable tubular element and the downstream inflatable tubular element are configured as an annular pocket of the sleeve, accommodating an inflatable supra and sub-annular balloon.

17. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the upstream tissue engaging spikes face towards a downstream side of the stent and the downstream tissue engaging spikes face towards an upstream side of the stent.

18. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the intermediate mesh section is configured and operable as an undulating section, axially extending between the upstream mesh section and the downstream mesh section.

19. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the intermediate mesh section integrally extends with the upstream mesh section and the downstream mesh section.

20. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the upstream mesh section extends in proximity below the upstream inflatable tubular element.

21. The prosthetic cardiac valve system according to any one of claims 7 to 20, wherein the downstream inflatable tubular element extends opposite at least a portion of the intermediate mesh section and a portion of the downstream mesh section.

22. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the projecting downstream spikes have a pointed end facing an upstream end of the stent. 30 304130/ - 26 -

23. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the stent and the elastic sleeve and the prosthetic cardiac valve are configured and operable as drug-eluting.

24. The prosthetic cardiac valve system according to any one of the preceding claims, wherein a nominal diameter of the stent of the prosthetic valve, at its deployed position, is greater than a nominal diameter of the stent at its deployed position, hence once deployed, the prosthetic valve is engageable within the elastic sleeve.

25. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the prosthetic cardiac valve is secured to the upstream elastic sleeve.

26. The prosthetic cardiac valve system according to any one of the preceding claims, wherein the prosthetic cardiac valve is secured at an inside face of the elastic sleeve.

27. The prosthetic cardiac valve system according to any one of the preceding claims, further comprising an inflating mechanism for inflating one or both of an upstream inflatable tubular element and a downstream inflatable tubular element.

28. The prosthetic cardiac valve system according to any one of the preceding claims, further comprising a detachable inflation tube detachably articulated with each of the upstream inflatable tubular element and the downstream inflatable tubular element.

29. A support structure for supporting a prosthetic cardiac valve as defined in any one of the preceding claims, wherein said support structure comprising a flexible tubular stent having an upstream mesh section and a downstream mesh section, with a radially deformable intermediate mesh section extending therebetween, and wherein the upstream mesh section is configured with a plurality of upstream tissue engaging spikes and the downstream mesh section is configured with a plurality of downstream tissue engaging spikes; wherein at an expanded position of the stent, said upstream tissue engaging spikes and said downstream tissue engaging spikes project radially outwards from an outside surface of the stent; and an upstream elastic sleeve extending over at least a portion of an inside/outside face of said upstream mesh section; said upstream elastic sleeve having an upstream inflatable tubular element disposed axially and radially upstream of said upstream mesh section.

30. The support structure of claim 29, being configured and operable between a constricted, deploying position at which it is at a closed position, and an expanded, open position at which it assumes a radially expanded position, and wherein at the closed 304130/ - 27 - position the upstream tissue engaging spikes and the downstream tissue engaging spikes are coplanar with an outside surface of the stent.

31. The support structure of claim 29 or 30, being configured and operable for use as a cardiac valve support for any one of the mitral valve, the aortic valve, the tricuspid valve and the pulmonary valve.

32. The support structure of any one of claims 29 to 31, for use in conjunction with a prosthetic cardiac valve system, wherein the support structure is a valve support for a prosthetic valve in the mitral position, and wherein the upstream inflatable tubular element is configurable for supra-annular positioning and inflating within the left Atrium.

33. The support structure of any one of claims 29 to 32, for use in conjunction with a prosthetic cardiac valve system, wherein the support structure is a valve support for a prosthetic Aortic valve, and wherein the upstream inflatable tubular element is configurable for sub-annular positioning and inflation.

34. The support structure of any one of claims 29 to 33, for use in conjunction with a prosthetic cardiac valve system, wherein the support structure is a valve support for a prosthetic Tricuspid valve, wherein the upstream inflatable tubular element is configured and operable for supra-annular positioning and inflating within the right atrium.

35. The support structure of any one of claims 29 to 34, for use in conjunction with a prosthetic cardiac valve system, wherein the support structure is a valve support for a prosthetic Pulmonary valve, wherein the upstream inflatable tubular element is configurable for sub-annular positioning and inflating within the right ventricle.

36. The support structure of any one of claims 29 to 35, further comprising a temporary valve positioned between the upstream and downstream mesh section at a non-deformable section of the support structure thereof, for temporarily regulating blood flow, in the direction corresponding with the normal hemodynamics, during a procedure of positioning and deploying the support structure, whereby upon positioning and deploying the prosthetic valve within the support structure, said temporary valve is over-ridden by the prosthetic valve.

37. A stent member for supporting a prosthetic cardiac valve, the stent member being a flexible tubular element having an upstream mesh section, a downstream mesh section and a radially deformable intermediate section extending therebetween, wherein the upstream mesh section is configured with a plurality of upstream tissue engaging spikes, 304130/ - 28 - and the downstream mesh section is configured with a plurality of downstream tissue engaging spikes, wherein said upstream tissue engaging spikes and said downstream tissue engaging spikes are made of memory shape material and are configured, at a closed position to be coplanar with an outside surface of the stent, and at an expanded deployed position of the stent, after being introduced in situ and reaching a predefined temperature to deform to their memory shape to project radially outwards from an outside surface of the stent to their radially outwards deformed position.

38. The stent member according to claim 37, wherein at its deployed, expanded position, the stent assumes a frustoconical shape wherein a narrow portion thereof is the upstream section of the stent.

39. The stent member according to claim 37 or 38, wherein the projecting spikes can be equally distributed about a perimeter of the stent.

40. The stent member according to any one of claims 37 to 39, wherein the projecting spikes have a triangle/ teardrop shape.

41. The stent member according to any one of claims 37 to 40, wherein at an initial, unstressed position, the stent is cylindric.