Small "functional" size after mechanical aortic valve replacement: No risk in young to middle-age patients

Background. The impact of a valve prosthesis-patient size mismatch is still controversial. In most studies, the inclusion of a large proportion of poorly active old patients with low cardiac output requirements may be misleading, due to the close correlation between transprosthetic gradients and cardiac output. The aim of this study was to assess the impact of small "functional" prosthesis sizes in active young to middle-age patients. Methods. Eighty-three active patients with a mean age of 46 +/- 8 years and a high health survey questionnaire score were followed for 80 +/- 34 months after isolated aortic valve replacement with a mechanical prosthesis. Results. Patients with an indexed, Doppler derived, effective orifice area index less than 0.85 cm(2)/m(2) (0.77 +/- 0.1 cm(2)/m(2)) showed higher early trans-prosthetic gradients (peak, 34 11 vs 26 8 mm Hg; P = 0.001) than patients with a larger effective orifice area index. However, significant regression of the left ventricular mass index and improvement of the left ventricular ejection fraction were observed in both groups at follow-up (119.8 +/- 26 vs 165.2 +/- 38 g/m(2) and 128.5 +/- 25 vs 181.8 5 0 g/m(2); P < 0.001; 58 6 vs 52 11% and 58 7 vs 53 10%; P < 0.001), with no differences between groups W = 0.4 and P = 0.7, respectively). At multiple linear regression, the final left ventricular mass index was positively related to the preoperative left ventricular mass index W = 0.004) and was unaffected by the effective orifice area index W = 0.4). Symptomatic improvement (New York Heart Association class 1.3 +/- 0.4 vs 2.4 +/- 0.8 and 1.2 +/- 0.4 vs 2.2 +/- 0.8; P < 0.001) and freedom from late cardiac death (93 +/- 3% and 95 +/- 6%) were comparable between groups W 0.6 and P 0.7, respectively). Conclusions. Our findings indicate that small "functional" prosthesis sizes with modem mechanical valves may not adversely affect outcomes of aortic valve replacement in young patients with high cardiac output requirements. (c) 2005 by The Society of Thoracic Surgeons.