Long-term Mortality Predictors in Patients with Small Aortic Annulus Undergoing Aortic Valve Replacement with a 19- or 21-mm Bioprosthesis

Introduction: Replacement of the aortic valve in patients with a small aortic annulus is associated with increased morbidity and mortality. A prosthesis-patient mismatch is one of the main problems associated with failed valves in this patient population. Objective: To evaluate the long-term mortality predictors in patients with a small aortic annulus undergoing aortic valve replacement with a bioprosthesis. Methods: In this retrospective observational study, a total of 101 patients undergoing aortic valve replacement from January 2000 to December 2010 were studied. There were 81 (80.19%) women with a mean age of 52.81±18.4 years. Severe aortic stenosis was the main indication for surgery in 54 (53.4%) patients. Posterior annulus enlargement was performed in 16 (15.8%) patients. Overall, 54 (53.41%) patients underwent concomitant surgery: 28 (27.5%) underwent mitral valve replacement, and 13 (12.7%) underwent coronary artery bypass graft surgery. Results: Mean valve index was 0.82±0.08 cm2/m2. Overall, 17 (16.83%) patients had a valve index lower than 0.75 cm2/m2, without statistical significance for mortality (P=0.12). The overall 10-year survival rate was 83.17%. The rate for patients who underwent isolated aortic valve replacement was 91.3% and 73.1% (P=0.02) for patients who underwent concomitant surgery. In the univariate analysis, the main predictors of mortality were preoperative ejection fraction (P=0.02; HR 0.01) and EuroSCORE II results (P=0.00000042; HR 1.13). In the multivariate analysis, the main predictors of mortality were age (P=0.01, HR 1.04) and concomitant surgery (P=0.01, HR 5.04). Those relationships were statistically significant. Conclusion: A valve index of < 0.75 cm2/m2 did not affect 10-year survival. However, concomitant surgery and age significantly affected mortality.