Current opinion Prosthesis patient mismatch in aortic valve replacement: possible but pertinent?

Aortic valve replacement (AVR) is now the second most com-monly performed cardiac operation and with an increasingly elderly population, the number of such procedures will inevitably continue to grow.1 In 1978, Rahimtoola2 defined the term prosthesis patient mismatch (PPM) to describe the situation in which the effective orifice area (EOA) of a prosthetic valve, after implantation, is smaller than that of the native valve. Although described nearly three decades ago, there are several reasons why PPM has only more recently become much more openly debated. First, PPM was initially overshadowed by the more immediate issues of operative mortality and major morbidity. Second, by definition, all prosthetic valves must therefore have at least some degree of PPM; over 90 % of AVR still use pros-theses with a sewing ring, or have struts, hinge mechanisms