Repair of truncus arteriosus in neonates with the use of a valveless conduit.

Each of seven infants 1 to 9 days old and weighing 2.1 to 3.3 kg with truncus arteriosus underwent repair of their defects with a right ventricular-to-pulmonary artery valveless conduit. Congestive heart failure and cyanosis were present before surgery in each. Five patients survived surgery and one of these subsequently died. Comparison between preoperative hemodynamics of the survivors and nonsurvivors disclosed similar peak systolic pulmonary arterial and aortic pressures, and pulmonary (Rp) or systemic resistance (Rs) in the groups. However, the mean Rp/Rs ratio in survivors (0.15) was significantly less than in nonsurvivors (0.63) (p = .001). The four remaining survivors are asymptomatic 7 months to 5.5 years after operation. Postoperative cardiac catheterization in three patients disclosed proximal conduit obstruction of 10 to 20 mm Hg in each, distal conduit obstruction of 35 mm Hg in two, and mild truncal valve stenosis and moderate truncal regurgitation in one each. We recommend the use of a valveless conduit for the symptomatic neonate with truncus arteriosus and a low Rp/Rs ratio (less than or equal to 0.03).