Objectives: This study was designed to determine the effects of age, coronary artery disease and other cardiac comorbidities on late outcome following bioprosthetic aortic valve replacement.
Methods: Data were prospectively collected on 670 patients undergoing aortic valve replacement with the Hancock II bioprosthesis (Medtronic, Inc, Minneapolis, Minn) between 1982 and 1994. Mean patient age was 65 +/- 12 years (median, 68 years; range, 18-86 years). Follow-up was 99.7% complete at 69 +/- 40 months (median, 66 months; range, 0. 1-168 months). Survival and freedom from reoperation were evaluated univariately by Kaplan-Meier analysis and multivariably by Cox regression.
Results: After adjustment for gender, Cox regression analysis revealed that age of 65 years or older, left ventricular dysfunction, the presence of coronary artery disease, and advanced New York Heart Association functional classification were associated with a higher risk of late death. At 12 years, survival was significantly different by Kaplan-Meier analysis for both age younger than 65 years (71% +/- 4%) versus age 65 years or older (36% +/- 7%; P <.0001), left ventricular function grades 3 and 4 (26% +/- 13%) versus grades 1 and 2 (59% +/- 4%; P <.0001), no coronary artery disease (65% +/- 4%) versus coronary artery disease (35% +/- 8%; P <.0001), and functional class IV (33% +/- 9%) versus classes I to III (62% +/- 4%; P <.0001). Only 9 patients experienced primary tissue failure, all of whom were younger than 65 years of age. At 12 years, the freedom from primary tissue failure was 84% +/- 4% for those patients younger than 65 years of age, and 100% for those 65 years of age or older (P =.006).
Conclusions: Long-term survival after aortic valve replacement is highly dependent on age, coronary artery disease, functional class, and left ventricular function, although bioprosthetic durability is dependent almost solely on age. Due to increased valve durability in patients who are 65 years of age or older, the Hancock II bioprosthesis may be an ideal aortic valve substitute in this age group. In patients who are younger than 65 years of age with advanced functional class, impaired left ventricular function, and coronary artery disease, this valve may also be used with a low probability of primary tissue failure. Patients without additional cardiac comorbidity may outlive their bioprosthetic valve, leading to reoperation.