Mid-term findings on echocardiography and computed tomography after RVOT-reconstruction: Comparison of decellularized (SynerGraft) and conventional allografts

Objective: The immune response against human-leucocyte-antigens on donor-cells may be an important factor contributing to the degeneration of allograft-valves. We have previously reported that the use of the decellularized allograft SynerGraft (CryoLife^®) reduces the immunologic response of the allograft-recipient. In this study we compare the echocardiographic and computed tomography angiographic (CTA) findings of SynerGrafts with conventional cryopreserved allografts. Methods: 22 patients who received a pulmonary SynerGraft (SG-group) (21 during a Ross-procedure) underwent CTA and resting echocardiography (median: 10 months postoperatively). 47 randomly chosen patients who underwent a Ross-procedure served as controls (C-group) (median: 32 months postoperatively). Results: Neither the pressure gradients (mean: SG=9±4 vs C=10±4 mmHg; P=0.64) across the allograft, nor the effective orifice area (EOAI) (SG=0.93±0.80 vs C=0.93±0.42 cm²/m²; P=0.96) differed between the groups. The EOAI showed a significant correlation with the smallest allograft-conduit-area measured on CTA (r=0.81; P<0.001) which was most frequently (n=34) found in the proximal postvalvular tubular part of the conduit. Calcifications (n=11) or a fibroproliferative reaction (n=15) were rarely observed. Overall, there were no radiologic differences between the groups. On CTA, the smallest diameter of the allograft-conduits was significantly smaller than the diameter given on the cryopreservation protocol (SG=16±3 and C=17±3 mm vs 25 mm in both groups; P<0.001 each) whereas the diameter of the distal part of the allograft was not (SG=24±2, P=0.066, and C=25±3 mm, P=0.82). Conclusions: Despite a significant shorter follow-up in the SynerGraft-group, no functional or radiologic differences were observed as compared to control-patients. The smallest diameter is located almost exclusively at the proximal level of allograft-conduits.