BACKGROUND: We planned a prospective study to evaluate the regression of left ventricular mass one year after surgery in older patients (<or=55 years) who have undergone aortic valve replacement with stentless bioprostheses or mechanical valve. MATERIAL/METHODS: Between 1998 and 2000, 54 patients had aortic valve replacement with stentless bioprostheses (14 CryoLife-O'Brien, 40 Medtronic Freestyle), and 62 patients had aortic valve replacement with St. Jude Medical mechanical valve. In preoperative echocardiographic evaluation, the St. Jude group had the highest left ventricular mass (LVM). The difference between groups was significant (O'Brien group: 329+/-75 g, Medtronic group: 382+/-116 g, St. Jude group: 445+/-138 g, p=0.006). The same level of statistical significance was achieved when LVM indexes were compared (LVMI; 192+/-39 g/m2, 217+/-65 g/m2, 255+/-78 g/m2, respectively, p=0.008). All the surviving patients were evaluated echocardiographically one year after surgery. RESULTS: Regression of LVM occurred in all patients after aortic valve replacement: 26% in the O'Brien group, 37% in the Medtronic group and 32% in the St. Jude group. The difference between the groups was not significant. LVM and LVMI's were significantly lower when compared with preoperative values, but the degree of regression was not different between groups one year after surgery. CONCLUSIONS: Regression of left ventricular mass after aortic valve replacement is directly related to the preoperative ventricular mass and independent of the valve type in older patients. The choice of prosthesis should be based on patient characteristics.

Keywords: Aortic Valve - surgery, Hypertrophy, Left Ventricular - physiopathology