Normal aortic valves stay open much longer in systole than porcine substitutes

• Published in: Asian cardiovascular & thoracic annals 2013-06, Vol.21 (3), p.275-280
• Main Authors: Subhani, Maboo, Kumar, Ramarathnam Krishna, Balakrishnan, Komarakshi R
• Format: Article
• Language: English
• Subjects: Animals; Aortic Valve - physiology; Bioprosthesis; Computer Simulation; Finite Element Analysis; Fixatives - pharmacology; Glutaral - pharmacology; Heart Valve Prosthesis; Hemodynamics - drug effects; Humans; Materials Testing; Models, Cardiovascular; Prosthesis Design; Systole - drug effects; Time Factors
• ISSN: 0218-4923; 1816-5370
• DOI: 10.1177/0218492312451981

Objective:To compare the opening mechanics of porcine valve substitutes with those of a normal human aortic valve. Background:All commercially available porcine valves are pretreated with glutaraldehyde. This study was undertaken to evaluate the consequences of such treatment on valve mechanics. Methods:The opening mechanics of the aortic valve, especially the time taken to open fully from a closed position, and the duration for which the valve is maximally open, were compared in a normal aortic valve, a stent-mounted porcine valve, and a stentless porcine valve, using a finite element model. Results:Despite a 4-fold higher gradient, stent-mounted porcine valves were slower in attaining the fully open position, and the time for which the valve was fully open was almost 25% less than a normal valve. In stentless valves, the compliant root made the initial opening mechanics similar to those of a normal valve. Once this effect was over, the effect of porcine leaflet properties took over, and there was a corresponding delay in the valve opening. Conclusions:Fixing the root with a stent and stiffening the leaflets with glutaraldehyde result in delayed valve opening and decrease the duration for which the valve is fully open, thus contributing to inferior hemodynamics.