Bare metal stenting for obstructed small diameter homograft conduits in the right ventricular outflow tract

Abstract

Our aim was to assess acute hemodynamic changes with stent insertion, outcomes, and factors associated with increased longevity of stented small diameter homograft conduits. Right ventricle-to-pulmonary artery (RV-PA) homograft conduits are commonly used to palliate RV outflow tract obstruction. Bare metal stenting (BMS) and transcatheter pulmonary valve implantation have been shown to relieve obstructed larger diameter conduits and may delay surgical conduit reintervention. Less is known about BMS of small conduits. From 1992 to 2009, BMS was performed to relieve obstruction in 106 homograft conduits that were ≤12 mm at implant. The peak RV-PA gradient fell from 54.3 ± 17.4 mm Hg at baseline to 46.1 ± 15.2 mm Hg after balloon dilation alone and to 25.1 ± 11.4 mm Hg with stenting (all P < 0.001). Higher pre-BMS gradient and RV pressure were the only factors associated with higher post-BMS RV-PA gradient (≥30 mm Hg; both P < 0.001). There were no procedural deaths, two patients required surgical removal of embolized stents. At a median follow-up of 1.6 years, 83 conduits were replaced; freedom from conduit reoperation after BMS was 66% ± 5% at 1 year and 28% ± 5% at 3 years. Factors associated with shorter freedom from reoperation included implanted conduit diameter <10 mm (P = 0.009), higher post-stent RV-PA gradient (P = 0.026), and higher post-stent RV pressure (P < 0.01); only post-stent RV pressure remained significant on multivariable analysis (P < 0.001). BMS was acutely effective for the treatment of obstructed small diameter homograft conduits, with low morbidity. Prolongation of small diameter homograft conduit longevity with BMS may be useful in the lifetime management of conduit dysfunction in this patient population.