US20090222076A1 - Self-Expandable Medical Instrument for Treating of Defects in a Patient's Heart - Google Patents

Abstract

The invention relates to a self-expandable medical instrument (100) for treating defects in a patient's heart, in particular for the transvascular implantation of a prosthetic heart valve (30), wherein the medical instrument (100) is introducible into the body of a patient in a minimally-invasive procedure using a catheter system (40) and comprises a stent (1) made of a flexible mesh (2) of thin wires or filaments (2′). In order to realize a positioning of medical instrument (100) in the patient's heart which is as precise as possible and to securely anchor same there, it is provided for the stent (1) composed of the flexible mesh (2) to exhibit in the expanded state of the medical instrument (100) a distal retention area (10) with a laterally-inverted beaded portion (12) which is engageable in at least one pocket (51) of the patient's defective heart valve (50), a proximal retention area (20), and a center area (15) positioned between the distal and the proximal retention area (10,20).

Description

• The present invention relates to a self-expandable medical instrument for treating defects in a patient's heart, in particular for the transvascular implantation of a prosthetic heart valve, whereby the medical instrument can be introduced via a catheter system into the patient's body in a minimally-invasive procedure. In particular, the invention relates to a device for the transvascular replacement of diseased heart valves.
• A device of this type is known in principle to medical technology. At present, biological or mechanical valve models are available to substitute for human heart valves which are usually fixedly sewn into the bed of the heart valve during a surgical procedure through an opening in the thorax after removal of the diseased heart valve. In this surgical procedure, the patient's circulation must be maintained by a heart-lung machine, whereby cardiac arrest is induced during the implantation of the prosthetic heart valve. This consequently makes the surgical procedure a risky one coupled with the associated risks for the patients and a lengthy post-operative treatment phase. In particular, the risks of such a surgical procedure are often no longer justifiable in the case of multimorbid patients.
• Minimally-invasive treatment procedures of recent development are characterized in particular by the surgery being able to be performed under local anesthesia. One approach provides for implanting a self-expanding stent connected to a collapsible heart valve into the human body by means of an appropriate catheter system. The catheter systems is used to guide such a self-expanding prosthetic heart valve through the inguinal artery or vein to its site of implantation at the heart. After reaching the site of implantation, the stent, consisting for example of a plurality of self-expanding stent segments which can be bent relative one another in its longitudinal direction, can then be successively expanded. Following this expansion, anchoring hooks can for example support the anchoring of the prosthetic heart valve at least in the respective blood vessel close to the heart. The actual prosthetic heart valve itself is thereby in the direct proximal area of the stent.
• Known for example from the DE 100 10 074 A1 printed publication is a device for fastening and anchoring prosthetic heart valves, which is essentially formed from wire-shaped interconnected elements. The device thereby provides for using various different arched elements in order to attain a secure fixation of and support for the prosthetic heart valve. To this end, the device described in this printed publication makes use of three identical pairs of arched elements, arranged to be offset from one another by 120°. These arched elements are interconnected by means of solid articulations, whereby the solid articulations fulfill the function of pivot bearings. Additional arched elements bent opposite to each other are furthermore provided which form rocker arms as equal in length as possible in order to achieve a secure placement of the arched elements even when subject to peristaltic actions on the heart and blood vessels and a solid sealing for an implanted and anchored prosthetic heart valve.
• In the known solutions, however, there is a risk of heart valve implant malalignment. This essentially relates to the exact positioning and longitudinal orientation of the prosthetic heart valve to be implanted. In particular, it is only with immense skill on the part of the attending surgeon—if at all—that a stent with the prosthetic heart valve at its proximal end winds up being positioned so precisely in the proximity of the patient's diseased heart valve that both sufficient lateral positioning accuracy as well as a suitable longitudinal placement to the prosthetic heart valve can be optimally ensured.
• Among other complications, an implantation malalignment of a less than optimally positioned prosthetic heart valve can lead to, for example, leakage or valvular regurgitation, which puts a substantial burden on the ventricle. Should, for example, a prosthetic heart valve be implanted too far above the actual heart valve plane, this can lead to occlusion of the coronary artery origination (coronaries) and thus to a fatal coronary ischemia with myocardial infarction. It is therefore imperative for an implanted prosthetic heart valve to meet all the respective requirements for both the accuracy of the lateral positioning as well as the longitudinal placement.
• In conventional implantation techniques in which self-expandable prosthetic heart valves are, for example, guided through a patient's inguinal artery to the site of deployment at the heart in a minimally-invasive procedure, the prosthesis is usually introduced using a guide wire and catheters, whereby conventional balloon catheters can also be used. Although such a surgical introduction can be monitored and controlled, for example with fluoroscopy (Cardiac Catheterization Laboratory=CCL) or with ultrasound (Transesophageal Echocardiogram=TEE), oftentimes—due to the limited maneuverability of the prosthetic heart valve which is still in a collapsed state during the introduction procedure and despite being in the collapsed state is still of relatively large size—it is not possible to ensure the required positioning accuracy and especially the longitudinal placement to the prosthetic heart valve implant with the corresponding anchoring elements affixed thereto. In particular—as a result of a possible coronary artery occlusion—an angle misalignment to the implanted prosthetic heart valve from the optimum site of deployment can pose a threat to the respective patient.
• In designing a prosthetic heart valve, special consideration must in particular be given to the substantial forces also acting on the prosthetic during the filling period of the cardiac cycle (diastole), necessitating a secure anchorage in order to prevent the implanted prosthetic heart valve from dislodging.
• Hence on the one hand, the prosthetic heart valve must be able to be maneuvered to the greatest extent possible in the respective coronary artery during the implantation procedure so as to ensure optimum positioning accuracy and, on the other hand, the implanted prosthesis must be able to be firmly anchored at its site of implantation in order to effectively prevent subsequent prosthesis misalignment.
• The present invention addresses the problem that the known devices for transvascular implantation and fixation of prosthetic heart valves are often not suitable for a simple implantation of a prosthetic heart valve with the required positioning accuracy. Moreover, explanting a previously implanted prosthetic heart valve in a minimally-invasive procedure or accordingly correcting an incorrectly positioned prosthetic heart valve has to date often only been possible with great effort, if at all.
• On the basis of the problems as set forth, one task on which the present invention is based is that of providing a device for the transvascular implantation and fixation of prosthetic heart valves which remedies the above-described disadvantages inherent to conventional implantation systems.
• According to the invention, this task is solved by a medical self-expandable instrument for treating heart defects in a patient, in particular for the transvascular implantation of a prosthetic heart valve, whereby the medical instrument can be introduced into the patient's body in a minimally-invasive procedure using a catheter system and a stent made from a flexible mesh of thin wires or filaments. It is thereby provided for the stent or the mesh to exhibit a first predefinable shape while the medical instrument is being inserted into the patient's body and a second predefinable shape when the medical instrument is in its implanted state, whereby the medical instrument is in a collapsed state in the first shape of the stent or mesh and in an expanded state in the second shape of the stent or mesh. In particular, in its expanded state, the medical instrument according to the inventive solution exhibits a distal retention area with a laterally-inverted beaded portion, which in the implanted state of the medical instrument is engageable with at least one pocket of the patient's defective heart valve, a proximal retention area, as well as a center area positioned between the distal and the proximal retention area. In its expanded state, the center area of the medical instrument thereby exhibits a smaller diameter than the proximal and/or distal retention area, whereby in the implanted state of the medical instrument at the height of the patient's defective heart valve, the center area is designed to form a positive connection with the vascular wall at or in the direct proximity of the defective heart valve.
• The advantages of the invention are in particular noted to be in the providing of a transvascularly introducible medical instrument, in particular for treating a patient's heart defects, whereby the medical instrument is suitable to be delivered by catheter to the defect to be treated in the patient's heart. Because the medical instrument is configured as a self-expandable instrument and essentially consists of a stent made of a flexible mesh of thin wires or filaments, one particularly advantageous result achieved is that the medical instrument—regardless of the size of the heart valve to be treated and regardless of the diameter to the defective heart valve—can self-adapt to the defective heart valve, and in such a way that, on the one hand, the portions of the medical instrument protruding into the bloodstream flowing past the implanted medical instrument are as small as possible, while at the same time, an optimal positioning, secure anchorage and optimal lateral sealing of the implanted medical instrument is ensured.
• Accordingly, the medical instrument is optimally positionable at the defective heart valve and anchored there in extremely stable manner, whereby at the same time, embolism-related problems can be prevented. Using thin wires or filaments as the source material of the stent or the medical instrument according to the invention respectively yields the further advantage of the medical instrument exhibiting long-term mechanical stability. This thus sustainably prevents structural fractures from occurring in the instrument employed. The mesh furthermore has sufficient rigidity.
• Briefly summarized, the solution according to the invention is characterized by the medical instrument comprising a stent made from a flexible mesh, in particular a wire mesh, which upon release from the catheter inverts in mushroom-shape form into the pockets of the diseased heart valve and is clamped there by this inversion. This thus provides an optimum positioning and stable anchoring of a prosthetic heart valve disposed or provided in the middle of the stent. At the same time, an optimum lateral sealing of the implanted prosthetic valve is ensured.
• Preferred embodiments of the medical instrument are indicated in the subclaims.
• A particularly preferred realization of the medical instrument according to the invention accordingly provides for the stent to furthermore exhibit a self-expandable prosthetic heart valve arranged in the center area which self-expands upon the medical instrument being released from the catheter system and which then assumes the function of the patient's defective heart valve. In this preferred embodiment, the mesh thus serves the medical instrument as a heart valve stent in the anchoring and positioning of the prosthetic heart valve arranged in the center area of the medical instrument. The medical instrument is in particular characterized by the fact that, due to its shape in the expanded state, it not only provides an extremely stable anchoring of the prosthetic heart valve, but also a self-positioning of same at the height of the defective heart valve to be replaced.
• With respect to the mesh which forms the prosthetic heart valve stent, it is preferably provided for same to be a mesh tube such that the medical instrument exhibits a form open to the proximal and distal end in its expanded state. A mesh tube offers the advantage of blood being able to flow through the medical instrument in the implanted state of the expanded medical instrument, whereby—except for the prosthetic heart valve disposed in the center area of the medical instrument—virtually no foreign components protrude into the bloodstream.
• It is furthermore conceivable for the beaded portion at the distal retention area of the stent in the expanded medical instrument to be formed by the mushroom-shaped outwardly turned-back distal end of the mesh. In particular, the beaded portion at the distal retention area of the expanded medical instrument in the implanted state of the medical instrument is thereby invertible in the at least one pocket of the patient's defective heart valve and thus serves as a self-positioning means for positioning the medical instrument at the height of the patient's defective heart valve.
• According to a further aspect of the present invention, because of the self-expanding properties of the stent made from the flexible mesh, the proximal retention area of the stent forms a force-fit connection with the vascular wall when the medical instrument is in its expanded state, thus ensuring a stable anchoring of the implanted medical instrument.
• On the other hand, the center area of the stent in the expanded medical instrument is advantageously configured such that based on the self-expanding properties of the stent made from the flexible mesh, the center area presses the patient's defective heart valve against the vascular wall distal the defective heart valve in the implanted state of the medical instrument.
• With respect to the shape of the medical instrument in its expanded state, the stent in its second shape respectively, it is preferable for same to be of a shape similar to a barbell, whereby both the distal as well as the proximal retention area are respectively configured in the shape of a mushroom cap. It is furthermore preferred for the center area of the stent to exhibit a smaller diameter in the expanded medical instrument compared to the proximal and distal retention areas, whereby the center area exhibits a length which corresponds approximately to the length of the defective heart valve.
• It is particularly preferred for the mesh-based stent having a self-expandable prosthetic heart valve arranged at its center area to taper to the diameter of the catheter system used in the transvascular surgical procedure.
• In order to allow for a medical instrument already implanted into the body of the patient being able to be subsequently explanted, a preferred further development of the solution according to the invention provides for the stent to exhibit a mounting engageable with an explantation catheter system on its proximal and/or distal end, wherein the medical instrument is moreover configured such that an external manipulation will effect its alteration from the expanded state to its collapsed state so that the medical instrument, the stent with the prosthetic heart valve respectively, will be as simple as possible to explant.
• A further aspect of the invention provides for the flexible mesh forming the stent for the self-expandable medical instrument to have a multi-layered configuration around the patient's defective heart valve in the implanted state of the medical instrument.
• Because a stent formed from a flexible mesh is used and because of the self-expanding properties to the medical instrument thus attained, it is particularly preferable for the stent with the self-expandable prosthetic heart valve arranged at its center area to be configured such that in the implanted state of the expanded medical instrument, the second shape of the stent, and thus the medical instrument, adapts to the anatomical conditions in such a manner that the prosthetic heart valve attains a maximum expansion on the one hand and, on the other, an optimum lateral sealing to the vascular wall is provided.
• It is of particular advantage for the stent made of flexible mesh, in particular wire mesh, with a self-expanding prosthetic heart valve arranged in its center area to be configured such that the stent with the prosthetic heart valve can be withdrawn back into the catheter system, and thus removable from the patient's body, at any time during the implantation of the medical instrument.
• It is provided for the flexible mesh to be made from nitinol or another material having shape-memory or memory effect. Other applicable materials would include, for example, copper/zinc/aluminum alloys, gold/cadmium alloys or also iron-based alloys such as, for example, iron/manganese, silicon alloys, as well as also plastics, which are all characterized by the fact that they have extremely high memory capabilities.
• Lastly, with regard to the use of the medical instrument, it is particularly preferred for the flexible stent of mesh with the prosthetic heart valve at its center area to be used not only for replacing aorta valves but also mitral, pulmonary and tricuspid valves.
• The following will make reference to the accompanying figures in describing the invention in greater detail, wherein the figures are as follows:
• FIG. 1 shows a preferred embodiment of the medical instrument according to the invention during insertion into the body of a patient, whereby the flexible mesh, which here forms the aorta valve stent, exhibits its first predefined shape;
• FIG. 2 shows the medical instrument ofFIG. 1 in a first state in which the aorta valve stent is released from the insertion catheter system;
• FIG. 3 shows the medical instrument ofFIG. 2 in a further second state during the release of the aorta valve stent from the insertion catheter system;
• FIG. 4 shows the medical instrument ofFIG. 3 in a further advanced third state during the release of the aorta valve stent from the insertion catheter system;
• FIG. 5 shows a state in which the aorta valve stent and thus the medical instrument according toFIGS. 1 to 4 is fully expanded and implanted at the height of the patient's heart valve;
• FIG. 6 shows a perspective view of the expanded medical instrument according to the preferred embodiment;
• FIG. 7 shows a conceivable route of implantation for the medical instrument according to the preferred embodiment.
• The embodiment depicted in the figures of the inventive self-expandablemedical instrument100 for treating defects of a patient's heart relates to a self-expandable medical instrument for the transvascular implantation of aprosthetic heart valve30, wherein themedical instrument100 can be introduced into a patient's body in minimally-invasive fashion by means of acatheter system40 and consists of a stent1 made from a flexible mesh (2) of thin wires or filaments2′.
• AsFIG. 1 shows, the stent1 configured from flexible mesh2 is in a first predefined shape during the insertion of themedical instrument100 into the patient's body. The stent1 further exhibits a self-expandableprosthetic heart valve30 at itscenter area15, which is covered by mesh2 inFIG. 1 and thus not explicitly shown. As will be described below, the self-expandableprosthetic heart valve30 unfolds by itself upon themedical instrument100, the stent1 respectively, being released from thecatheter system40.
• What can in particular be noted fromFIG. 1 is that the stent1 configured from mesh2 with theprosthetic heart valve30 arranged at its center area15 (not explicitly shown inFIG. 1) tapers to the diameter of thecatheter system40 used for the transvascular procedure. In this state, themedical instrument100 is seen as being in its collapsed state.
• FIG. 1 specifically depicts a state immediately prior to themedical instrument100 in its collapsed state being brought through thedefective aorta valve50 of the patient to the ascending aorta by means of aguide wire41, and after themedical instrument100 having been transseptally inserted into the left ventricle by aninsertion catheter system40. As already indicated, only the flexible mesh2 can be recognized in the depiction of themedical instrument100 shown in theFIG. 1 representation, same assuming the function of the aorta valve stent1 and with the (not explicitly depicted) collapsedprosthetic heart valve50 disposed at itscenter area15.
• FIG. 2 shows a state in which—starting from the position shown in FIG.1—the first portion of the inner wire mesh2 of stent1 is mushroomed out of the correspondinginsertion catheter system40, whereby this portion forms the beadedportion12 at thedistal retention area10 of the stent in the fully expanded state ofmedical instrument100, arching laterally in a mushroom shape. In the implanted state ofmedical instrument100, the laterally outward cappingbeaded portion12 engages in at least onepocket51 of the patient'sdefective heart valve50, as will be described in detail below.
• FIG. 3 shows a further state in which the entire stent1 is drawn back to the height of thedefective aorta valve50, where thedefective valve50 is hooked in form-fit manner to the “midriff” of stent1; i.e., thecenter area15 of the double-mushroomed stent1 after full expansion, after the distal (upper) portion of the wire mesh2 inverts into place and the beadedportion12 is fully formed.
• FIG. 4 meanwhile shows a state in which by the further extending of stent1 formed from the mesh2 out of thecatheter system40, the self-expandableprosthetic heart valve30 disposed in thecenter area15 within stent1 emerges. In this state, the patient's defective (old)valve50 engages with themidsectioned center area15 of stent1. The beadedportion12 at thedistal retention area10 of stent1 is furthermore turned inside out by the mushroom-shaped inverting of the distal end of mesh2, whereby the beadedportion12 turns to fit into thepockets51 of the patient'sdefective heart valve50 so as to serve as a means for positioning themedical instrument100 at the height of the patient'sdefective heart valve50.
• Upon stent1 being further extended from thecatheter system40, theproximal retention area20 of stent1 finally unfolds, whereby same then forms a force-fit connection with thevascular wall52 in the direct proximity of thedefective heart valve50 due to the self-expanding properties of the mesh2. At the same time, thecenter area15 of stent1 presses against theaorta wall52, whereby the self-expandable mesh2 expands further, thereby clamping theprosthetic valve30.
• BothFIG. 5aandFIG. 5bshow a state in which the mechanicalprosthetic heart valve30 is correctly positioned and fully closed, whereby the defective (old)valve50 remains in the heart and is pressed against thevascular wall52. Moreover indicated is how, following a check of the proper seating and the error-free functioning of the mechanicalprosthetic heart valve30, theguide wire41 can then be removed again. It is hereby pointed out that in the event of valve malfunction, theguide wire41 can retract stent1 with the integratedprosthetic heart valve30 back into the insertion catheter system as necessary and the stent can be replaced by another stent with an integrated prosthetic heart valve.
• FIG. 6 shows a perspective view of the expandedmedical instrument100 in accordance with the preferred embodiment. It can be recognized that in the expanded state ofmedical instrument100, the stent1 exhibits a barbell-like shape, whereby the stent1 formed from the flexible mesh2 with the self-expandableprosthetic heart valve30 disposed within thecenter area15 of stent1 (not recognizable inFIG. 6) is configured such that the second shape of stent1 in the implanted state of the expandedmedical instrument100 can adapt to the anatomical conditions in such a manner that theprosthetic heart valve30 attains maximum expansion on the one hand and, on the other, achieves an optimum lateral sealing tovascular wall52.
• It can further be noted fromFIG. 6 that in the expanded state ofmedical instrument100, thecenter area15 of stent1 exhibits a smaller diameter than the proximal anddistal retention areas10 and20, whereby thecenter area15 exhibits a length which corresponds approximately to the length of thedefective heart valve50.
• The embodiment of themedical instrument100 as depicted moreover provides for the stent1 to have a mounting4 in the form of a ring at its proximal end which can be brought into engagement with a (not shown) explantation catheter system, whereby themedical instrument100 is configured such that external manipulation can commute it from its expanded state into its collapsed state.
• FIG. 7 shows how aguide wire41 can be fed through the vena cava to the right atrium and the interatrial septum in the left atrium and further into the left ventricle and from there through the left ventricular outflow tract and the aorta valve to the ascending aorta.
• It is particularly preferred for the transvascular replacement of a patient'sdefective aorta valve50, for example, to sew or otherwise fasten a suitableprosthetic valve30 in the middle of thecenter area15 of the stent1 configured from flexible mesh2. The stent1 with the integratedprosthetic valve30 can then be tapered to the diameter of thecatheter system40 used in the transvascular surgical procedure and brought through the venous system, passing the interatrial septum, from the right atrium into the left atrium and from there, further into the left ventricle and the left ventricular outflow tract by means of the insertion catheter system.
• The stent1 configured from mesh2 is released from theinsertion catheter system40 at the height of the defective (old)aorta valve50, as is shown inFIG. 1. Because stent1 is discharged successively, at first only thedistal retention area10 is released such that it upends inside out in mushroom shape, as depicted inFIGS. 2 to 4. Subsequent thereto, a careful guiding of themedical instrument100 toward the ventricles will bring the beadedportion12 into a form-fit connection in thepockets51 of the patient's defectiveold valve50. The middle midriff, thecenter area15 respectively, of stent1, in which theprosthetic valve30 is disposed, is now in form-fit seating at the height of the old heart valve (50), as shown inFIG. 4.
• Theproximal retention area20 of stent1 is then also subsequently ejected from thecatheter system40, whereby the artificialprosthetic valve30 expands and at the same time, the olddefective heart valve50 is pressed againstwall52 due to the self-expanding properties of the wire mesh2 (cf.FIG. 5). In this state, the beaded orflanged portion12 at thedistal retention area10 turns inversely outward into the left ventricular outflow tract and thus effects an additional mechanical support and secure anchorage for the medical instrument. In the event of any malfunctioning of stent1 with the integratedprosthetic valve30, theguide wire41 still tethered to stent1 can effect its removal as necessary, as is indicated inFIGS. 5aand5b.
• It is not imperative to have the route of implantation for the double-mushroom-shaped heart valve stent1 be transvenous and through the interatrial septum. It is just as conceivable to perform a retrograde implantation procedure through the aortic arch with acatheter system40 in the manner as described above. The heart valve stent1 constructed in this manner with its givenmedial midriff15 furthermore offers the opportunity of the integrated mounting (ring) of stent1 subsequently re-fixing onto the integratedprosthetic heart valve30 and collapsing same by the longitudinal extension of the wire mesh such that it can be removed again through a catheter tube.
• The entire detailed route of implantation is depicted inFIG. 7. Aguide wire41 is first introduced through the venous system to the right atrium and through the interatrial septum into the left atrium. From the left atrium, the guide wire is pushed through the left ventricle and the left ventricular outflow tract into the aorta (FIG. 7). Using theguide wire41 as a rail, theinsertion catheter40 is now advanced into the left ventricular outflow tract and the aortic valve plane. The implantation of the valve as described above now follows.
• Alternatively, aguide wire41 coming from the aortic arch can be pushed in retrograde manner through the aortic valve into the left ventricle. A similar implantation of the aortic valve stent1 as indicated above is now possible here with a modified catheter tube.
• By a design-contingent integration of retaining elements on the self-expandable stent1, same can also be explanted again with a special catheter subsequent a successful implantation. To this end, the distal orproximal retention area10,20 of stent1 should be drawn byguide wire41 into acatheter40 at a plurality of, preferably more than three retaining punctures. In so doing, reversed as in implantation, the mushroom-shapedproximal beaded portion22 at theproximal retention area20 of stent1 is buffeted back, whereby the wire mesh2 expands again and assumes a state as shown inFIG. 4. Subsequently, the engagement or anchoring of the beadedportion12 ondistal retention area10 of stent1 with thepockets51 of the body's own defective heart valve can be disengaged.
• The stent1 composed of the flexible wire mesh2 with theprosthetic valve30 integrated in itscenter area15 and adapted to the valve ring and, where necessary, to the outflow tract of the human heart, can be used in similar fashion for replacing mitral valves as well as replacing pulmonary or tricuspid valves.
• It is obvious that the following features in particular distinguish the solution according to the invention over the medical instruments as known to date for the transvascular replacement of diseased heart valves:
• • 1. With the stent configured from the self-expandable mesh with a prosthetic valve disposed in the middle thereof, the old diseased heart valve is enfolded, reversely pushed in and pressed against the vascular wall.
  • 2. The prosthetic valve in the stent can be implanted both in antegrade (via transseptal puncture) as well as retrograde procedures.
  • 3. The stent, the flexible mesh respectively, optimally self-adapts to the anatomical conditions of the valve ring and the heart's outflow tract, which thereby achieves a better lateral sealing for the implanted medical instrument.
  • 4. In the event of the prosthetic valve malfunctioning, the stent with the integrated prosthetic valve can be retracted back through the insertion catheter system and removed completely from the patient's body.
  • 5. Compared to conventional stent valves, the great degree of flexibility to the wire mesh allows implantation even in the case of highly angular approaches.
  • 6. The self-expanding wire mesh can be used to replace both the valves of the left as well as the right ventricle and to replace both the atrioventricular valve as well as also the semilunar valve of the heart, since it flexibly adapts to the anatomical conditions and surrounds the old diseased valve.
  • 7. Reversely pushing in the old diseased valve into the self-expanding wire mesh prevents embolization of portions of the old valve.
  • 8. The design-contingent integration of retaining elements on the self-expanding wire mesh also allows for same to be explanted again with a special catheter subsequent a successful implantation.
• It is pointed out that the realization of the invention is not restricted to the embodiments described with reference toFIGS. 1 to 7, but is also possible in a plurality of other variants.
REFERENCE NUMERALS
• 1 stent
• 2 mesh
• 2′ filaments/wire of the mesh
• 4 mounting
• 10 distal retention area of the stent
• 12 beaded portion at the distal retention area
• 15 center area of the stent
• 20 proximal retention area of the stent
• 22 beaded portion at the proximal retention area
• 30 prosthetic valve
• 40 catheter system
• 41 guide wire
• 50 body's own heart valve
• 51 pocket of body's own heart valve
• 52 vascular wall
• 100 medical instrument

Claims (17)

1. A self-expandable medical instrument (100) for treating defects in a patient's heart, in particular for the transvascular implantation of a prosthetic heart valve (30), wherein the medical instrument (100) can be introduced into the body of a patient in a minimally-invasive procedure using a catheter system (40) and comprises a stent (1) made from a flexible mesh (2) of thin wires or filaments (2′), wherein the stent (1) configured from flexible mesh (2) exhibits a first predefinable shape during the insertion of the medical instrument (100) in the patient's body and a second predefinable shape in the implanted state of the medical instrument (100), wherein said medical instrument (100) is in a collapsed state in the first shape of the stent (1) composed of the flexible mesh (2) and in an expanded state in the second shape of the stent (1) composed of the flexible mesh (2), and wherein the stent (1) composed of the flexible mesh (2) in its second predefinable shape and in the expanded state of the medical instrument (100) exhibits the following:

a distal retention area (10) having a laterally-inverted beaded portion (12), which in the implanted state of the medical instrument (100) is engageable in at least one pocket (51) of the patient's defective heart valve (50);

a proximal retention area (20); and

a center area (15) positioned between the distal and the proximal retention area (10,20),

wherein the center area (15) of the stent (1) of the expanded medical instrument (100) exhibits a smaller diameter than the proximal and/or distal retention area (10,20), and wherein the center area (15) is configured to form a positive connection with the vascular wall (52) at the height of the defective heart valve (50) in the implanted state of the medical instrument (100).

2. The self-expandable medical instrument (100) according toclaim 1, wherein the stent (1) further exhibits a self-expandable prosthetic heart valve (30) disposed in the center area (15) which self-expands upon the medical instrument (100) being released from the catheter system (40).

3. The medical instrument (100) according toclaim 1 or2, wherein the mesh (2) is a mesh tube, and wherein the medical instrument (100) exhibits a form open to the proximal and distal end in its expanded state.

4. The medical instrument (100) according to any one of the preceding claims, wherein the beaded portion (12) at the distal retention area (10) of stent (1) in the expanded medical instrument (100) is formed by the mushroom-shaped outwardly turning back of the distal end of mesh (2).

5. The medical instrument (100) according toclaim 4, wherein the beaded portion (12) at the distal retention area (10) of stent (1) in the expanded medical instrument (100) in the implanted state is invertible into at least one pocket (51) of the patient's defective heart valve (50) and thus serves as a means for positioning the medical instrument (100) at the height of the patient's defective heart valve (50).

6. The medical instrument (100) according to any one of the preceding claims, wherein based upon the self-expanding properties of the mesh (2), the proximal retention area (20) of the stent (1) in the expanded medical instrument (100) is configured so as to form a force-fit connection with the vascular wall (52) in the direct proximity of the defective heart valve (50) in the implanted state of the medical instrument (100).

7. The medical instrument (100) according to any one of the preceding claims, wherein based upon the self-expanding properties of the mesh (2), the center area (15) of the stent (1) in the expanded medical instrument (100) is configured so as to press the patient's defective heart valve (50) against the vascular wall (52) distal the defective heart valve (50) in the implanted state of the medical instrument (100).

8. The medical instrument (100) according to any one of the preceding claims, wherein the stent (1) in the expanded state of the medical instrument (100) exhibits a shape similar to a barbell.

9. The medical instrument (100) according to any one of the preceding claims, wherein the center area (15) of the stent (1) exhibits a smaller diameter in the expanded medical instrument (100) than the proximal and distal retention areas (10,20), and wherein the center area (15) exhibits a length which corresponds approximately to the length of the defective heart valve (50).

10. The medical instrument (100) according to any one of the preceding claims, wherein the stent (1) made of mesh (2) with a self-expandable prosthetic heart valve (30) arranged at its center area (15) tapers to the diameter of the catheter system (40) used in the transvascular surgical procedure.

11. The medical instrument (100) according to any one of the preceding claims, wherein the stent (1) exhibits a mounting (4) engageable with an explantation catheter system (40) on its proximal and/or distal end, and wherein the medical instrument (100) is configured such that an external manipulation will effect its commuting from its expanded state into its collapsed state.

12. The medical instrument (100) according to any one of the preceding claims, wherein in the implanted state of the expanded medical instrument (100), the flexible mesh (2), in particular wire mesh, of stent (1) is disposed in multi-layered arrangement around the defective heart valve (50).

13. The medical instrument (100) according to any one of the preceding claims, wherein the stent (1) made of flexible mesh (2), in particular wire mesh, having a self-expandable prosthetic heart valve (30) arranged at its center area (15) is configured such that the second shape of stent (1) is adaptable in such a manner to the anatomical conditions so as to achieve on the one hand a maximum expansion of prosthetic heart valve (30) and, on the other, an optimum lateral sealing to the vascular wall (52) in the implanted state of the expanded medical instrument (100).

14. The medical instrument (100) according to any one of the preceding claims, wherein the stent (1) made from flexible mesh (2), in particular wire mesh, having a self-expandable prosthetic heart valve (30) arranged at its center area (15) is configured such that the stent (1) with the prosthetic heart valve (30) can be withdrawn back into the catheter system (40) and removable from the body of the patient at any time during the implantation of the medical instrument (100).

15. The medical instrument (100) according to any one of the preceding claims, wherein the stent (1) made from flexible mesh (2), in particular wire mesh, having a self-expandable prosthetic heart valve (30) arranged at its center area (15) is configured such that using a catheter system (40) and guide wires (41), the stent (1) with the prosthetic heart valve (30) is again retractable and explantable following a successful release.

16. The medical instrument (100) according to any one of the preceding claims, wherein the flexible mesh (2) is made from a material having memory effect, in particular nitinol or memory plastics.

17. The medical instrument (100) according to any one of the preceding claims, wherein the stent (1) made from flexible mesh (2), in particular wire mesh, having a self-expandable prosthetic heart valve (30) arranged at its center area (15) is configured so as to replace a patient's aorta valve, mitral valve, pulmonary valve or tricuspid valve.

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