Superior durability of synergraft pulmonary allografts compared with standard cryopreserved allografts

Background. The ideal pulmonary valve replacement for children and adolescents remains elusive. Although favored by many surgeons, the cryopreserved pulmonary allograft tends to become rapidly incompetent and elicits an immune response. The SynerGraft process (Cryolife Inc, Kennesaw, GA) decellularizes a pulmonary allograft, leaving a scaffold of connective tissue. These grafts have been shown to decrease immune reactivity and become populated with host cells. Although theoretically these traits may improve durability, few data comparing SynerGraft-processed allografts (SynAs) (Cryolife Inc) with standard cryopreserved allografts are available. Methods. A single institution review was performed for all SynAs implanted from their introduction in 2001 to January 2003. Twenty-six patients with SynAs and 26 age and diagnosis-matched controls receiving cryopreserved allografts were evaluated. Subjects were analyzed for demographics, survival, reintervention, and echocardiographic findings. Results. There were no significant differences between groups in age, weight, valve diameter, orthotopic and heterotopic allograft position, or follow-up. On echocardiogram there was no difference in initial degree of allograft insufficiency or gradient. However, at mean follow-up of 19 +/- 13 months, SynAs were significantly less regurgitant than cryopreserved allografts (p=0.017). Although all gradients were low, a significant difference between SynAs (7.6 +/- 14 mm Hg) and cryopreserved allografts (14.6 +/- 15.6 mm Hg; p=0.012) had emerged. Survival was identical at 85% (22 of 26). Rates of reintervention were similar at 7% (2 of 26) for cryopreserved allografts and 3.8% (1 of 26) for SynAs (p=0.98). Conclusions. At intermediate follow-up, the SynA demonstrated greater durability with less insufficiency and lower gradients. These characteristics are important to many patients with complex congenital heart disease; however, long-term effects on survival and reintervention remain unknown.