Strategies for biological heart valve replacement: stentless xenografts fail to evolve into an alternative pulmonary valve substitute in a Ross procedure.

The Ross operation is a complex procedure for aortic valve replacement in which the pulmonary autograft is replaced by a homograft. However, homograft availability is becoming limited. This report evaluates the performance of porcine stentless prostheses as alternative pulmonary substitutes. Echocardiographic results from two patient cohorts were compared at time of discharge and 1 year after a Ross procedure. Thirty-three patients (median age 42 years, range 17-62 years, 76% male) received a stentless prosthesis (median size 25.6 mm, range 25-29 mm) for right ventricular outflow tract reconstruction. Clinical data were not significantly different from 106 patients (median age 47 years, range 2-68 years, 75% male) who received cryopreserved homografts (median size 26 mm, range 20-33 mm). At time of discharge, peak pressure gradients (ΔPmax ) across the stentless valve (median ΔPmax 13 mmHg, range 2-26 mmHg) were higher compared to homografts (median ΔPmax 7 mmHg, range 1-32 mmHg, p<0.001). At 1 year, gradients increased in both groups, but were significantly higher across stentless valves (median ΔPmax 23 mmHg, range 10-81 mmHg vs. median ΔPmax 13 mmHg, range 2-74 mmHg, p<0.001). Eleven patients (33%) in the stentless-valve group were classified "at risk" with a ΔPmax of ≥30 mmHg. Four of them (12%) had to be re-operated. In conclusion, stentless valves showed higher pressure gradients and their performance was inferior to cryopreserved homografts. See accompanying commentary by Ulrich Stock DOI: 10.1002/biot.201200341.