Survival to six months for sheep with a non-biostable polyurethane mitral heart valve prosthesis has been reported previously, however, with surface degradation and accumulation of calcified fibrin/thrombus that impaired leaflet motion and compromised hydrodynamic function. Newly available biostable polyurethanes may overcome this problem.
Six adult sheep with biostable polyurethane trileaflet heart valve prostheses of documented hydrodynamic performance, implanted in the mitral position, were allowed to survive for 6 months. Explanted valves were photographed, resubmitted to hydrodynamic function testing, and studied by light and electron microscopy.
Explanted valves were structurally intact and differed little in appearance from their preimplant state. Hydrodynamic testing showed no deterioration in pressure gradient or energy losses compared with pre-implant values.
Biostable polyurethanes demonstrated improved blood compatibility leaving leaflets flexible and valve function unimpaired. Biostable polyurethanes may thus improve prospects for prolonged function of synthetic heart valve prostheses.
BernaccaG.M., MackayT.G., WheatleyD.J.In vitrocalcification of bioprosthetic heart valves: report of a novel method and review of the biochemical factors involved.J Heart Valve Dis1992; 1: 115–30.
3.
ChandranK.B., FatemiR., SchoephoersterR.In vitro comparison of velocity profiles and turbulent shear distal to polyurethane trileaflet and pericardial prosthetic valves.Int J Artif Organs1989; 13: 148–54.
4.
HilbertS.L., FerransV.J., TomaitaY., EidboE.E., JonesM.M.Evaluation of explanted valves: performance and blood compatibility.Life Support Systems1987; 4: 130–2.
5.
LoH.B., HeroldM., ReulH.A tricuspid polyurethane heart valve as an alternative to mechanical prostheses or bioprostheses.Trans Am Soc Artif Int Organs1988; 34: 839–44.
6.
KolffW.J., YuL.S.The return of elastomer valves.Ann Thorac Surg1989; 48: S98–9.
7.
NistalF., Garcia-MartinezV., ArbeE., FernandezD., MazzoraF., GalloI.In vivo experimental assessment of polytetrafluoroethylene trileaflet heart valve prosthesis.J Thorac Cardiovasc Surg1990; 99: 1074–81.
8.
ChettaG.E., LloydJ.R.The design, fabrication and evaluation of a tri-leaflet prosthetic heart valve.J Biomech Eng1980; 102: 34–41.
ImamuraB., KayeM.P.Function of expanded polytetrafluoroethylene laminated tri-leaflet valves in animals.Mayo Clin Proc1977; 52: 770–5.
11.
TanziM.C., AmbrosioL., NicolaisL., IannaceS., GhislanzoniL., MambritoB.Comparative physical tests on segmented polyurethanes for cardiovascular applications.Clin Mater1991; 8: 57–64.
12.
ZdrahalaR.J., ZdrahalaI.J.Biomedical applications of polyurethanes: a review of past promises, present realities and a vibrant future.J Biomater Appl1999; 14: 67–90.
13.
JansenJ., ReulH.A synthetic three-leaflet valve.J Med Eng Technol1992; 16: 27–33.
14.
BernaccaG.M., MackayT.G., WheatleyD.J.In vitro function and durability of a polyurethane heart valve: material considerations.J Heart Valve Dis1996; 5: 538–42.
15.
BernaccaG.M., MackayT.G., WilkinsonR., WheatleyD.J.Calcification and fatigue failure in a polyurethane heart valve.Biomaterials1995; 16: 279–85.
16.
BernaccaG.M., MackayT.G., WilkinsonR., WheatleyD.J.Polyurethane heart valves: fatigue failure, calcification and polyurethane structure.J Biomed Mater Res1997; 34: 371–9.
17.
WheatleyD.J., RacoL., BernaccaG.M., SimI., BeleherP.R., BoydJ.S.Polyurethane: material for the next generation of heart valve prostheses?Eur J Cardio-thorac Surg2000; 17: 440–8.
RhodesN.P., ShortlandA.P., HuntJ.A., DohertyP.J., WilliamsD.F.In vivo biostability of polyurethanes purported to be biologically stable. Proceedings of the 25th Annual Meeting of the Society for Biomaterials, Providence, Rhode Island: 1999; 62.
20.
WheatleyD.J., FisherJ., WilliamsD.F.Heart Valve Prosthesis. International Patent Number W09832400, 1998.
21.
FisherJ., ButterfieldM., WheatleyD.J., WilliamsD.F.A new design of polyurethane heart valve.J Heart Valve Dis2001 (in press).
22.
BernaccaG.M., O'ConnorB., WheatleyD.J.Hydrodynamic function of polyurethane prosthetic heart valve: influences of Young's modulus and leaflet thickness.Transactions of the Sixth World Biomaterials Congress, Kamuela, Hawaii: 2000; 584.
23.
O'ConnorB., BernaccaG.M., StraubI., WheatleyD.J.Mechanical testing of flexible polyurethanes: candidate selection for a prosthetic heart valve.Transactions of the Sixth World Biomaterials Congress, Kamuela, Hawaii: 2000; 294.
