Decellularized pulmonary homograft (SynerGraft) for reconstruction of the right ventricular outflow tract: first clinical experience

Introduction Cryo-preserved homograft valve conduits have been used to reconstruct the right and left ventricular outflow tract. Long-term studies have shown homograft degeneration and calcification, and it has been postulated that immunological mediated phenomena in a manner similar to that seen in chronic rejection may contribute to the degeneration process. The development of a decellularized, non-glutaraldehyde-fixed valve conduit creates a non-immunogenic connective tissue matrix for autologous recellularization by host cells. The aim of the study was to characterize the clinical and hemodynamic pattern in human implants of the novel decellularized pulmonary homografts (SynerGraft). Methods Reconstruction of the right ventricular outflow tract was performed in 17 patients: 15 patients with aortic valve disease and the Ross procedure, and two patients with redo procedures following Fallot tetralogy and severe pulmonary regurgitation. Patients with the Ross procedure with standard cryopreserved homografts as neo-pulmonic conduits served as controls. Within the follow-up over six months morphological and hemodynamic parameters were characterized by echocardiography: maximal and mean pressure gradient across the right and left ventricular outflow tract, their effective orifice areas, determination of neopulmonic and neoaortic regurgitation. Results One patient died six weeks following surgical treatment due to non-valve related end-stage cardiopulmonary failure; all patients were free of valve-related complications during the follow-up period. The matched Ross patients showed a gradual but significant increase of both the maximal and mean pressure gradient across the right ventricular outflow tract (DeltaP max 5.5 +/- 2.5 to 11.4 +/- 6.4 mmHg, p = 0.002; DeltaP mean 3.0 +/- 1.3 to 6.2 +/- 3.9 mmHg, p = 0.003), whereas in the SynerGraft group increase of pressure gradients were measurable but did not reach statistical significance (DeltaP max 7.1 +/- 3.7 to 10.1 +/- 3.9 mmHg, p = 0.11; DeltaP mean 3.6 +/- 1.6 to 5.5 +/- 2.3 mmHg, p = 0.12). The pulmonary effective orifice areas decreased in the control group from 1.74 +/- 0.33 to 1.18 +/- 0.36 cm(2)/m(2) (p=0.001). Within the SynerGraft group time dependent reduction of the orifice area was significantly less cm(2)/m(2). (1.51 +/- 0.37 to 1.25 +/- 0.26 p = 0.08). Conclusion Up to six months after implantation reconstruction of the right ventricular outflow tract with decellularized homografts was safe, stable, and the morphological and hemodynamic features are promising.