Objectives: Although stentless aortic bioprostheses are believed to offer improved outcomes, benefits remain unsubstantiated. The aim of our study was to compare stentless with stented bioprostheses, with regard to postoperative changes in left ventricular mass and hemodynamic performance, in the elderly patient. Methods: Forty patients with aortic stenoses, over the age of 75 years, were randomized to receive either the stented Perimount (n = 20) or the stentless Prima Plus (n = 20) bioprosthesis. Left ventricular mass regression, effective orifice area, ejection fraction and mean gradients were evaluated at discharge, 6 months and 1 year after surgery. Results: Overall a significant decrease in left ventricular mass was found 1 year postoperatively. However, there was no significant difference in the rate of left ventricular mass regression between the groups. Furthermore, 1 year postoperatively, the hemodynatnic performance of the valves and the change in the ejection fraction did not differ between the groups. Conclusions: Our study shows that in a randomized cohort of elderly patients with aortic stenosis, we were not able to detect significant differences, with regard to hemodynamic performance and regression of left ventricular mass, between the stentless and stented valve groups. To our surprise, previously reported findings of non-randomized trials that showed faster and more complete regression of left ventricular mass and hemodynamic benefits of stentless valves were not reproducible. (C) 2002 Elsevier Science B.V. All rights reserved.