Design and manufacture of a polyvinyl alcohol (PVA) cryogel tri-leaflet heart valve prosthesis.
Although current artificial heart valves are life sustaining medical devices, improvements are still necessary to address deficiencies. Bioprosthetic valves have a compromised fatigue life, while mechanical valves have better durability but are prone to thromboembolic complications. A novel, one-piece, tricuspid valve, consisting of leaflets, stent and sewing ring, made entirely from the hydrogel, polyvinyl alcohol cryogel (PVA-C), has been developed and demonstrated. This valve has three thin leaflets attached to a cylindrical stent. In order to approximate the complex shape of the surface of the natural heart valve leaflets, two different geometries have been proposed: revolution about an axis of a hyperboloid shape and revolution about an axis of an arc subtending (joining) two straight lines. The parameters of both geometries were examined based on a compromise between avoiding sharp curvature of leaflets and minimization of the central opening of the valve when closed. The revolution of an arc subtending two straight lines was selected as the preferred geometry since it has the benefit of a smaller central opening when the value of the maximum curvature for the leaflets is the same for each valve geometry. A cavity mold has been designed and constructed to form the PVA-C heart valve. The three leaflets were formed and integrated into the stent and sewing ring in a single process. Prototype heart valves were manufactured in the mold from a solution of PVA and water, by controlled freezing and thawing cycles.
Jiang
Hongjun
H
National Research Council of Canada, Integrated Manufacturing Technologies Institute, London, Ontario, Canada N6G 4X8.
Campbell
Gord
G
Boughner
Derek
D
Wan
Wan-Kei
WK
Quantz
Mackenzie
M
D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry; D003198:Computer Simulation; D017076:Computer-Aided Design; D019544:Equipment Failure Analysis / Q000379:methods; D006350:Heart Valve Prosthesis; D006351:Heart Valves / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry; D008420:Manufactured Materials; D008955:Models, Cardiovascular; D010865:Pilot Projects; D011142:Polyvinyl Alcohol / Q000138:chemical synthesis / Q000737:chemistry*; D011474:Prosthesis Design / Q000379:methods*; D015607:Stents
D001672:Biocompatible Materials; D020100:Hydrogels; D011142:Polyvinyl Alcohol