Patient-Prosthesis Mismatch: State of the Art and Implications for Long Term Results

Patient-prosthesis mismatch (PPM) was reported for the first time by Rahimtoola [1] in 1978 and it occurs when the effective orifice area (EOA) indexed for the body surface area (BSA) is less than that of a normal human valve. Several studies using the indexed EOA have shown the negative impact of PPM on clinical outcomes: in fact, it seems to be related with less improvement in symptoms, i.e. functional class, lesser regression of left ventricular mass and with an higher rate of early mortality in particular when left ventricular low ejection fraction is associated and adverse events during long-term follow-up [2-3]. Although some studies [4] suggest that an increased mortality can occur only in presence of a critical level of obstruction, i.e. PPM <0.4cm2/m2, numerous recent studies showed a negative outcome also in presence of a less degree of PPM.