BACKGROUND: An increasing number of surgeons prefer to place a conduit from the right ventricle to the pulmonary artery at the time of the Norwood stage I procedure. Proximal conduit stenoses have led us to modify this technique by using ring-enforced polytetrafluoroethylene conduits. METHODS: Angiograms of 24 patients with conventional conduits (CC) and 28 patients with ring-enforced conduits (RC) before partial bidirectional cavopulmonary anastomosis were analyzed. The degree of conduit stenosis on three different levels--proximal anastomosis, substernal part of the conduit, and distal anastomosis--was compared between the two groups. RESULTS: In the RC group, the extent of conduit stenosis at the level of proximal anastomosis and within the substernal proximal third of the conduit was minimized (23% +/- 22% vs 45% +/- 22%, p = 0.001, and 7% +/- 6% vs 49% +/- 26%, p < 0.001, respectively). At the level of the anastomosis with the pulmonary arteries, results were similar in the RC group (24% +/- 14%) vs CC group (31% +/- 15%, p = 0.103). Significantly fewer patients in the RS group required urgent intervention (dilatation +/- stenting) or early stage II operation (1 vs 6 patients, p = 0.034). CONCLUSIONS: The use of a ring-enforced polytetrafluoroethylene conduit between the right ventricle and the pulmonary artery in Norwood stage I palliation effectively prevents substernal compression and reduces interstage morbidity.