Hemodynamic performance of the Ionescu-Shiley valve prosthesis

Abstract

The hemodynamic performance of the Ionescu-Shiley bovine heterograft valve has been evaluated by intraoperative measurement of transvalvular gradients and cardiac outputs. Effective orifice areas (EOAs) were calculated and the data compared to those obtained by other investigators for other prostheses. In the aortic position, each valve, from 19 to 31 mm external diameter, produced a pressure gradient; mean EOA increased with increasing valve size, so that small (19 to 23 mm) valves were moderately stenotic and larger valves were only mildly stenotic. The presence of a mitral prosthesis produced larger transaortic valve gradients, probably as a result of aortic outflow obstruction by the mitral prosthesis. The Ionescu valve appears to be hemodynamically superior to other biological valves in the aortic position and comparable to most mechanical prostheses, although the data for comparison are scant. Each mitral valve produced a pressure gradient and, on the average, larger (29 mm) valves performed no better than smaller (25 mm). Mean EOAs for each valve size (25 to 29 mm) were adequate to provide satisfactory hemodynamics comparable to other available prosthetic valves. Mild obstruction of the left ventricular outflow by the prosthetic struts was seen to be related to the distance between ventricular septum and the struts. Most currently available prostheses seem to provide similar hemodynamics in the mitral position, and considerations such as thrombogenicity and durability may be relatively more important in the choice of a mitral valve substitute than in the choice of an aortic valve substitute.