WO2025079086A1

WO2025079086A1 - Prosthetic heart valve with sewing ring

Info

Publication number: WO2025079086A1
Application number: PCT/IN2024/051957
Authority: WO
Inventors: Kurian Valikapathalil MATHEW
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-10-11
Filing date: 2024-10-04
Publication date: 2025-04-17
Anticipated expiration: 2026-04-11

Abstract

This invention deals essentially with the sewing ring or sewing ring which is attached to the prosthetic valve by means of which the prosthetic valve is sewed into the heart. The general form of the sewing ring as per this invention will be that of a cylindrical hollow tube and the pores/holes in the sewing ring assist the needle and sewing thread be passed more easily for attachment to the natural tissues of the body and also be firmly positioned with the prosthetic valve.

Description

Tl TLE : “PROSTH ETI C H EART VALVE WI TH SEWI NG Rl NG”

Fl ELD OF I NVENTI ON :

The invention relates to a sewing ring for heart valve prosthesis which helps to fix the heart valve prosthesis inside the heart and particularly is related to sewing rings with internal surfaces which are typically exposed to the outside surface of the body of the heart valve prosthesis and its external surfaces which are typically exposed to the heart tissue to which the prosthesis is sutured.

BACKGROUN D OF I NVENTI ON :

Many types of sewing rings are known and used in prior art in heart valve prosthesis.

These prior art sewing rings of the heart valve prosthesis are made with a cylindrical “solid body” formed into a ring form and are made of biocompatible synthetic materials like fabrics or plastic polymers. The sewing ring is fixed on the outside surface of the valve body and the surgical sutures are inserted through the solid body of the sewing ring when the heart valve prosthesis is implanted inside the heart of the patient.

Although these prior art solid sewing rings of the heart valve prosthesis are made with biocompatible materials, complete healing or tissue incorporation is not possible because of the solid nature of the ring and the tightly fixed location of the sewing ring after the implantation of the valve. It is because of these reasons wherein substantially sewing ring of the valve continues to remain as a foreign body, that the patients after heart valve replacement have to be kept on lifelong anticoagulation to prevent blood clotting over the valve. These incomplete healing process is the reason for the major complications after heart valve replacement like valve thrombosis, prosthetic valve endocarditis and Pannus. OBJECTS OF TH E I NVENTI ON :

The object of the present invention is to provide a sewing ring for heart valve prosthesis in which the aforesaid sewing ring is elim inated but standard requirement of valve prosthesis is also satisfied simultaneously without giving rise to any new problems by using a novel sewing ring design/ material hitherto unknown in prior art. This invention can elim inate to a large extent the inconveniences and disadvantages of the prior art heart valve prosthesis which includes lifelong anticoagulation, valve thrombosis, prosthetic valve endocarditis and Pannus.

SUMMARY OF THE I NVENTI ON :

According to the present invention, the object of the invention is achieved by virtue of a novel sewing ring having characteristics recited specifically in the claims and disclosed herein.

The sewing ring for the heart valve prosthesis has a flexible and resilient hollow annular body forming a hollow tube which is made up of porous fabric in single layer or multiple layers made up of biocompatible materials like polypropylene, PTFE, or any other appropriate materials.

Further the tubular structure for making the sewing ring may be made of single or multiple layers of biocompatible porous fabric material and preferably formed according to the criteria demanded for that sewing ring in terms of layers.

The sewing ring may also optionally include reinforcement with additional support structures to maintain the resilience of the tubular shape with flexible materials with memory like thin wires made with Nitinol or any other appropriate materials arranged longitudinally or circularly and the arrangement may be like coil type, spring type or rod type. These reinforcements may be incorporated in the porous fabric itself in case of single layer or m ultilayer design, or it may be incorporated inside or outside the single or multiple layered fabric tube.

DESCRI PTI ON OF THE I N VENTI ON :

When the valve of heart becomes weak, heart valve prosthesis are used to replace the natural valves of the heart. These heart valve prosthesis are secured inside the heart by suturing through the sewing ring of the prosthesis and through the heart valve annulus. The invention deals with a novel sewing ring specifically which is criteria in prior art.

The sewing ring is attached to the valve body and by provision of a porous material such as those disclosed permit easy suturing and further allow tissues to grow through the sewing ring material and further assist in holding the prosthetic valve in place.

The sewing ring is attached to the outside surface of the valve body using various PRIOR ART techniques like metal rings, springs, plastics and threads. Typically the outside surface of the valve housing is adapted to incorporate the sewing ring. The reason for eliminating the solid sewing ring is detailed below :

The prior art sewing ring has to be of some bulk for two reasons : (a) for performing the role of holding the structure of the valve and (b) for enabling the implantation of the valve to the heart tissue. The basic design and principle of sewing ring remaining generally the same in prior art by, there are also many methods/differences between all types of mechanical valves and in “materials used” and the mechanism of fixing the sewing ring onto the outer surface of the valve body. While implanting the valve, the sutures need to be passed through the sewing ring. The fabric used in the prior art sewing rings are porous and the advantage of the porosity of fabric is negated by the multilayer construction and the tight packing of the sewing ring.

The selected material as per invention that is used to make the tubular hollow ring is essentially biologically inert and “POROUS”. The porosity of the fabric material is maintained and advantageously because of the single layer or minimal number of layers design and also the hollow inside lumen of the sewing ring body. The porosity of the sewing ring material selected as per this invention will assist the capillaries and fibrous tissues to grow onto the ring material and get it incorporated into the native heart valve annulus very easily and in a shorter duration. This will ensure good healing of the annulus after implantation of the heart valve and thus helps to prevent the inconveniences and disadvantages of the prior art heart valve prosthesis which include lifelong anticoagulation, valve thrombosis, prosthetic valve endocarditis and Pannus.

It is to be noted that the main advantage of mechanical heart valve is its durability but its surface is generally not compatible with blood and it can activate blood clotting. If the foreign body such that the sewing ring of the artificial valve is porous and amenable to tissue growth, it can get integrated to the tissues easily and when there is complete tissue integration, the implant will behave like an integral part of the surrounding tissues and does not produce foreign body reaction. Hence the aim is to achieve the best mode of integrating the implant with the body tissues using a novel sewing ring unknown in prior art.

However due to increased bulk of current sewing ring as known in prior art complete tissue integration does not happen very easily as, due to bulky multilayered fabric covering the sewing ring, which is reducing its porosity. Hence the aim is to reduce the bulkiness of the sewing ring and have a sewing ring which is non-bulky and highly porous.

The object of the invention is achieved as per invention by providing a desired embodiment which is alternative to the bulky sewing ring of prior art and by substituting it with biocompatible hollow tubular sewing ring with memory which can integrate easily with the native heart tissues so as to effectively reduce the inadequacies and the complications associated with prior art prosthetic heart valve replacement and detailed herein above.

The other object achieved is to reduce the bulk as well as reduce the potential sites for bacterial colorization by providing a much thinner ring in comparison with prior art ring but exhibiting better advantage unknown in prior art. The sewing ring as per invention collapses into a thin flap unlike prior sewing ring which continue to remain bulky occupying a layer space [refer fig. 1 ] ,

The sewing ring is adaptable for various sizes.

The sewing ring as per invention is hollow tube of appropriate size made up of biocompatible material. The diameter of the hollow tube may vary with the size and type of the prosthetic valve. But the material is such that is always soft and always easily compressible. The memory for the tube is added advantage i.e., the tube will rebound when the compressing pressure disappears. This will make the tube dynamic when it is being implanted and so also after implantation. This dynamic nature of the sewing will help it to occupy the irregular contours of the tissue annulus post implantation and thus help to prevent the complication of paravalvular leak.

The tube can also be made non-dynamic but compressible when pressure is applied so that it will not rebound back when the pressure is taken off. The option is flexible for selection based on the requirement of a specific valve.

The tubular body of the sewing ring remains compressed wherever the pressure remains and bulges out and occupies the space wherever there is no compressing pressure. This is the advantage and essential feature exhibited by the sewing ring. The sewing ring can be shaped as coil like or spring like or multiple rings like or lace like skeleton with thread made up of Nitinol or polypropylene or any other appropriate material. This coil or rings of the tube is stabilized by longitudinally running wires or threads for reinforcement which is optional. This dynamic skeleton can be made in single layer or in multiple layers. The thickness of the wires or the threads used for the skeleton can be of any thickness, but the thinnest possible will be ideal or atleast most preferred.

The dynamic skeleton which is used for reinforcement of the tube is covered by porous mesh or porous fabric or bunch of threads made up of polypropylene or any other appropriate material. The material can be with or without memory characteristics. This covering can be made in a single layer or in m ultiple layers and the thickness of the covering may vary. The porosity of the covering may vary, but the maximum porosity possible with retention of adequate structural integrity is preferred. The covering on the dynamic skeleton of the tube can be on the inside surface or on the outside surface or on both sides.

Instead of a skeleton and a covering over that, the whole tube can be made in a single integrated layer with all the above mentioned characteristics. The integrated tube may be molded or prepared with appropriate material like polypropylene. The main invention lies in the detail with its core novelty in the sewing ring which is made with the hollow tube. The hollow tube thus prepared is made into a ring of appropriate size according to the size of the valve. The ends of the tube can be joined together by telescoping the ends or by any other appropriate technique and can be attached together with sewing or welding or any other appropriate technique. The ends of the tube can be joined together by joining together of the longitudinally running wires or threads.

In one option there is no filling material inside the lumen of the tube.

In another option, the inside of the lumen of the tube can be filled with biodegradable or soluble materials.

Regarding the attachment of the sewing ring to the valve body, the details are given herein:-

As per invention, in one option the novel sewing ring made of the hollow tube will be attached on the outside of the valve body using any of the available known techniques used for fixing the sewing ring to the valve body. It may be single or multiple metal rings, single or multiple threads, stitching or welding or any other appropriate known technique.

In this the ring is prepared at the end of the process of fixing the sheets to valve body unlike the first option which uses prepared ring.

In another option, the fabric can be made in the form of a rectangular sheet or strip of appropriate width and this sheet is fixed to the outside surface of the valve body using the known techniques like single or multiple metal rings, single or m ultiple threads, stitching or welding or any other appropriate technique. After fixing the sheet or strip to the outside surface of the valve body, the edges of the sheet or strip can be joined together with sutures, ties, hooks or any appropriate technique so that the sheet or strip now become a ring with a tubular body.

In another option, the skeleton of the sewing ring can be incorporated in the valve body during the course of manufacturing of the valve body and the prepared sewing ring is attached to valve body thereafter as disclosed in option

1 above.

In another option, the skeleton for the sewing ring can be integrated into the valve body during the course of manufacturing of the valve body and the option

2 disclosed above can be performed.

This sewing ring so constructed is adaptable to be attached to all types of known mechanical valves and hence adaptable for a wide range of mechanical valves available in the market currently.

This sewing ring so constructed is adaptable to be attached to all types of bioprosthetic (tissue) valves and hence exhibits an extraordinary industrial application and enjoys vast utility valve.

BRI EF DESCRI PTI ON OF TH E DRAWI NGS:

Fig. 1 illustrates the cross section of mechanical heart valve with the sewing ring of the invention and also the tissue annulus ( 17) . The dynam ic hollow compressible sewing ring in the open position ( 15) . The dynamic hollow sewing ring is compressed and collapsed when the heart valve is implanted at the annulus hollow lumen (16) of the sewing ring has disappeared.

Fig. 2 illustrates the hollow tube made of porous fabric. The porous fabric material ( 1 ) is illustrated at the bottom as a sheet and the top illustrates the tube (2) formed with the fabric and lumen (3) is also illustrated.

Fig. 3 illustrates the sewing ring constructed with dynamic hollow porous fabric tube. The outside surface (4) of the sewing ring com ing in contact with the heart valve annulus tissue. The inside surface (5) of the sewing ring coming in contact with the valve body.

Fig. 4 is a cross section of the valve body (7) with the hollow dynamic sewing ring (8) and the fixing metal ring (9) It also illustrates the dynamic porous fabric in a strip form (6) attached to the outer surface of valve body.

Fig. 5 illustrates the cross section of the mechanical valve showing the valve body (10) , the sewing ring ( 1 1 ) and the rings (12) used to fix the sewing ring over the valve body. The open sewing ring may be open. The edges will be joined together. The dynamic hollow compressible sewing ring made of porous fabric.

Fig. 6 illustrates complete valve assembly - valve body (13) with bileaflets (occlude) (14) mounted with the sewing ring (15)

With all details disclosed herein, the sewing ring as disclosed herein was unknown in prior art and the orifice valve with the sewing ring as disclosed herein was unknown in prior art. Hence the disclosure is for a product which is new and novel unknown in prior art.

Although the present invention has been described with reference to preferred embodiments, it should be understood that various changes, alteration or modification may be made to the invention, as described herein without departing from the spirit and scope of the invention.

Claims

W E CLAI M :

1 . A heart valve prosthesis with a sewing ring with its internal surface adapted to be exposed to outer surface of valve body and its external surface adapted to be exposed to heart valve annulus comprising of : a. sewing ring which is a flexible and resilient hollow annular body forming a hollow tube prepared from a porous fabric in a single or plurality of layers, and b. a reinforcement material arranged longitudinally or circularly incorporated into the porous fabric, or incorporated inside the hollow tube or incorporated outside the hollow tube. the said arrangement characterized in that the sewing ring is a sewing ring with memory and also sewing ring is high porous, such that the dynam ic nature of the memory of sewing ring enables the sewing ring to occupy the irregular contours of the tissue annulus post the implantation and the high porosity advantageously enables improved tissue growth and in this combination there is elim ination of requirement of anticoagulation, valve thrombosis, prosthetic valve endocarditis and pannus after implantation.