Background

Structural deterioration of allografts over time is believed to be at least partly related to an immune response mounted against human leukocyte antigen specific to the transplanted tissue. SynerGraft (SG) processing (CryoLife, Kennesaw, GA) is a technology that decellularizes an allograft leaving only connective tissue, therefore, reducing immunogenicity and potentially increasing durability of the implant.

Methods

We performed a retrospective review of 163 SG patients and 124 standard allograft controls from 3 medical centers. Patient demographics were tabulated, and conduit stenosis and insufficiency were measured by echocardiography.

Results

There were 28 deaths (15 of 163 [9%] SG patients vs 13 of 124 [11%] standard patients; p = 0.72), but no deaths were attributed to structural failure of the conduit. The actuarial survival for SG vs standard cohorts was not different at 5 and 10 years. Among the 274 hospital survivors, 17% SG vs 42% standard had evidence for significant conduit dysfunction at the most recent follow-up or before conduit replacement. Freedom from conduit dysfunction was significantly worse at 10 years in the standard group (58%) than in the SG group (83%, p < 0.001).

Conclusions

This study represents a multiinstitutional retrospective comparison of SG and standard cryopreserved allografts used in right ventricular outflow tract reconstruction in a broad range of patient ages. Our results demonstrate that at an intermediate-term to long-term follow-up, conduit dysfunction and pulmonary insufficiency and stenosis are higher among patients receiving standard allografts. We postulate that the improved durability of SG is related to decreased immunogenicity of the SG technology.