Left ventricular mass regression following implantation of MIRA bileaflet valves in patients with severe aortic stenosis

The aim of this study was to evaluate the factors that determine the course of left ventricular mass regression in a homogeneous group of patients following aortic valve replacement by use of the mechanical Edwards MIRA bileaflet prosthesis. Furthermore, we examined if the 19-mm valve leads to an equally good outcome when compared with larger 21- and 23-mm valves. We included 79 patients (49 men) with a mean age of 65 +/- 9 years operated on for isolated aortic valve replacement with the MIRA valve prosthesis. The analyses included preoperative and postoperative echocardiograms during a follow-up of at least 18 months (995 +/- 439 days) after valve surgery. Indication for valve replacement was aortic stenosis in 59 and combined disease (aortic stenosis and regurgitation) in 20 patients. Concomitant coronary artery bypass grafting was performed in 28 patients. Left ventricular mass index declined from 155.6 +/- 47 g/m(2) to 128.8 +/- 35 g/m(2) (P < 0.001) at final visit and normalized in 49% of the patients. Female sex and a preoperatively highly elevated left ventricular mass index were identified as risk factors for residual hypertrophy. However, age and valve size did not have a predictive value for completeness of left ventricular mass regression. This study supports the evidence that an extensive preoperative left ventricular hypertrophy results in an incomplete postoperative mass regression in patients with aortic bileaflet valves. It shows that the slightly elevated pressure gradient in MIRA 19-mm valves does not affect left ventricular mass regression.