Performance and Durability of Cryopreserved Allograft Aortic Valve Replacements

The value of allografts for aortic root replacement is controversial, with recent concern about limited durability. Currently, we prefer allografts for invasive infective endocarditis. Purposes of this study were to assess allograft performance and durability in our cumulative experience with aortic allografts.

From January 1987 to January 2017, 2042 adults received 2110 aortic allograft root replacements at our institution: 986 (47%) for infective endocarditis (669 [68%] for prosthetic valve endocarditis) and 1124 (53%) for other indications. Mean recipient age was 54 ± 15 years, and mean allograft donor age was 35 ± 13 years. Follow-up was 85% complete and comprised 17,253 patient-years of data. Longitudinal allograft performance was extracted from 6339 available echocardiographic studies. Durability was assessed by explant for allograft structural failure.

Allograft mean gradient at hospital discharge was 6 mm Hg and 9, 13, and 15 mm Hg at 5, 10, and 15 years post-implant, respectively. Severe aortic regurgitation was 0% at hospital discharge, but 14%, 25%, and 35% at 5, 10, and 15 years, respectively. A total of 405 allografts were explanted for structural failure, actuarially 2%, 14%, 34%, and 51% at 5, 10, 15, and 20 years, respectively. Risk factors for structural failure were younger recipient age, larger body surface area, hypertension, and thoracic aorta disease; donor factors were older age and larger allograft size. Implant for infective endocarditis was not associated with accelerated structural failure.

This study affirms allografts' long-term acceptable hemodynamic performance and durability. Concern about structural failure should not limit allograft use. Recipient hypertension, allograft size, and donor age are modifiable risk factors.