Stentless valves versus stented bioprostheses at the aortic position: midterm results

Our aim was to compare stentless and stented bioprostheses. Clinical outcomes, hemodynamic performance, and postoperative left ventricular mass regression were the principal outcomes assessed.

Sixty-two patients were recruited for the study. Our protocol was to consider all patients older than 55 years for bioprostheses, and also younger patients were implanted with a bioprosthesis if they wanted to avoid anticoagulation. Patients selected for bioprostheses were randomly assigned to receive stentless (group A) and stented (group B) bioprostheses, depending on the treating unit. Patients in groups A and B were further divided into subgroups I and II based on left ventricular ejection fractions of 50% or greater and less than 50%, respectively.

At 18 +/- 3 months postoperatively, the effective orifice area was greater in group A versus group B. Left ventricular ejection fraction, left ventricular mass index, functional class, and mean gradient were similar in patients of subgroup I (left ventricular ejection fraction >50%) from both groups. However, there was a significant difference between all except mean gradient in patients of subgroup II (left ventricular ejection fraction <50%) from both groups. Also, in the patient subgroup implanted with valves of less than 19 mm (group A, 4 patients; group B, 3 patients), there was a significant difference in left ventricular mass index and mean gradient.

In patients with left ventricular impairment or a small aortic annulus, stentless bioprostheses might allow for greater improvement in left ventricular function postoperatively.