Patient-prosthesis mismatch after aortic valve replacement; tolerable lower limit of indexed effective orifice area

This study was aimed at determining the tolerable lower limit of the indexed effective orifice area (EOAI) to prevent patient-prosthesis mismatch (PPM). Echocardiography was performed in 87 consecutive patients who underwent aortic valve replacement (AVR). EOAI was estimated for each type and size of prosthesis and used to define PPM as moderate if >0.65 cm2/ m2 and < or = 0.85 cm2/m2, and severe if < or = 0.65 cm/m2. Aortic valve pressure gradients, left ventricular dimensions, and outcome (in-hospital and 1-year) were analyzed in the presence or absence of abnormal gradients (> or = 40 mmHg) to assess the influence of a small valve (19 mm or less labeled size). Severe PPM was found in 23% of all patients, and 50% of the severe PPM patients had an abnormal gradient. There was 1 death and 1 brain damage from ventricular fibrillation because of severe PPM in the abnormal gradient group with a small valve. In PPM patients with a small valve, EOAI (0.61 +/- 0.04 vs 0.69 +/- 0.07) and preoperative interventricular septal thickness (IVST : 16.4 +/- 2.6 mm vs 13.5 +/- 1.5 mm) were significantly different between abnormal and normal gradient groups. An EOAI > or = 0.69 appeared to be tolerable in patients with a lower level of hypertrophy (IVST < 16 mm).