Suture rings for prosthetic heart valves

#The present invention relates to suture rings for implanting heart valve prostheses and more particularly to improved suture rings configured to facilitate insertion of a heart valve in a patient, which are adapted to inhibit excessive tissue growth proximate the heart valve.

#A wide variety of heart valve prostheses have been developed to operate in conjunction with the pumping action of the heart to take the place of defective natural valves. These valves variously have valve bodies which are designed to function with one or more occluders or leaflets to open and close a central blood flow passageway through the valve body.

#As a means for inserting heart valves into the heart, the valves commonly have attached fabric members suturable to the tissues of the heart. Frequently the fabric member is attached to a separate suture ring which is applied to the periphery of the heart valve body or orifice ring, for example, as described in U. S. Pat. Nos. 3,763,548 and 4,535,483. Conventional sewing rings or suture rings are made of Dacron (.TM.) fabric which enables a surgeon to suture the prosthetic valve to the residual valve ring after the defective valve has been removed. However, there is some incidence of failure of mechanical heart valves that is attributed to tissue overgrowth from the fabric members into an interference location with the moving mechanical parts of the heart valves.

#In the following detailed description, reference will be made to the attached drawings in which:

#FIG. 1 is a exploded perspective view of a heart valve body and a suture ring assembly, embodying various features of the invention, for insertion in a mitral location;

#FIG. 2 an exploded cross-sectional view of the heart valve body and suture ring assembly of FIG. 1;

#The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. In addition, the general principles of the invention are also described in Disclosure Document No. 359105 filed on Aug. 5, 1994 and incorporated by reference herein.

#Referring to FIG. 1 and FIG. 2, there are illustrated perspective and cross section views of a first embodiment of the heart valve body 10 and suture ring assembly 20 particularly adapted for insertion in a mitral location. The suture ring assembly 20 includes a retaining ring 22 and a suture ring 24. The suture ring 24 further comprises three basic elements including a suture flange 25, an interior flange 27 or protrusion and a suture ring body 29. The valve body 10, retaining ring 22, and suture ring 24 are all preferably made from pyrocarbon or pyrocarbon coated substrates as is commonly used in the art. More importantly, the suture flange 25 portion of the suture ring 24, in the preferred embodiment, is not made from conventional fabric materials but rather is also made from pyrolytic carbon or other similar, non-porous, thromboresistant and bio-compatible material.

#Alternative materials well known in the biomedical art can be used instead of pyrocarbon, such as titanium, zirconium and corrosion-resistant alloys such as Zircaloy. Appropriate strong, nonreactive ceramic materials, including zirconium oxide, zirconium nitride and zirconium carbide might also be used. If desired, many of these materials can be coated with strongly adherent exterior coatings of pyrocarbon.