ABSTRACT
Bioprosthetic valve replacements are now widely used in the aortic position, but there are several disadvantages to the conventional stented bioprostheses. Conventional stented porcine bioprostheses have an effective orifice area less than that of the left ventricular outflow tract1 and this may leave unacceptable outflow tract obstruction, especially in the small aortic root or if there is mismatch between the valve and the patient.1-3 The physical presence of the stent itself also leads to a degree of outflow obstruction and consequently to a less favourable haemodynamic profile.
