AORTIC-VALVE REPLACEMENT WITH STENTLESS AND STENTED PORCINE VALVES - A CASE-MATCH STUDY

Objectives: To assess the potential benefits of the hemodynamic superi ority of stentless valves, we conducted a case-match study among patie nts who underwent aortic valve replacement with two types of porcine b ioprostheses: the Toronto SPV and the stented Hancock II bioprosthesis . Methods: Preoperative clinical variables predictive of death after a ortic valve replacement were determined by a stepwise logistic regress ion analysis in a series of 908 consecutive patients who received porc ine aortic bioprostheses during a 14-year interval, Advanced age, New York Heart Association functional class IV, left ventricular ejection fraction of less than 30%, and coronary artery disease were independen t predictors of death, On the basis of these four variables, 198 pairs of patients who survived aortic valve replacement with stentless and stented porcine valves were matched. The follow-up, truncated to the s hortest interval for each matched pair, was 43 +/- 24 months for both groups. Results: At 8 years the actuarial survival was 91% +/- 4% for the Toronto SPV group and 69% +/- 8% for the Hancock II group (p = 0.0 06); the freedom from cardiac-related death was 95% +/- 4% for the Tor onto SPV and 81% +/- 8% for the Hancock II (p = 0.01); the freedom fro m any valve-related complication was 81% +/- 5% for the Toronto SPV an d 50% +/- 10% for the Nancock II (p = 0.008), A Cox proportional hazar d model demonstrated a significant reduction in cardiac mortality rate s and valve-related morbidity in patients who received the Toronto SPV bioprosthesis. Conclusions: Although it is possible that confounding factors may have played a role in the clinical outcomes of this case-c ontrol study, the study suggests that aortic valve replacement with a stentless porcine valve enhances survival. This is believed to be due to the hemodynamic superiority of these valves.