Subcoronary allograft aortic valve replacement: parametric risk-hazard outcome analysis to a minimum of 20 years.

Background: Differences in sterilization, preservation, and implantation have been implicated in aortic allograft longevity. We report follow-up to 30 years of patients from a single unit who underwent aortic valve replacement with aortic allografts sterilized in antibiotics and refrigerated at 4 degrees C.
Methods: Two hundred consecutive patients underwent subcoronary allograft aortic valve replacement and have been followed up to a minimum of 20 and maximum of 30 years. Follow-up was 96% complete. Parametric hazard phase modeling was used to identify incremental predictors of time-related risk.
Results: Early mortality was 1.5%. Kaplan-Meier actuarial survival, including early death, was 81.2% +/- 2.8% (mean +/- standard error of the mean), 58.0% +/- 3.7%, and 52% +/- 5.1% at 10, 20, and 25 years, respectively. Freedom from reoperation for any reason was 86.4% +/- 2.6%, 39.6% +/- 5.2%, and 35.0% +/- 5.4% at 10, 20, and 25 years, respectively. Larger implanted valve, reexploration for bleeding, previous cardiac surgery, and operative rank were independent risks for reoperation. Early mortality in reoperations was 5.1%. Allograft endocarditis has occurred in 6 patients, giving an overall freedom of 94% at 25 years. Seven patients of the original cohort are known to be alive with their original allograft valve in situ, and of these the longest follow-up period is 29.8 years.
Conclusions: The use of antibiotic-sterilized allografts for subcoronary aortic valve replacement confers low operative mortality and excellent long-term survival with durability matching any other nonmechanical device. Significantly reduced time-related risk of reoperation and excellent internal to external diameter ratio renders allograft aortic valve replacement especially ideal for smaller roots.