Subclavian-to-pulmonary artery anastomoses with interposition polytetrafluoroethylene (PTFE) conduits provide excellent early palliation for many forms of cyanotic heart disease. It is important to assess whether patients with this condition maintain adequate arterial oxygenation without developing pulmonary artery distortion or hypertension. From October, 1980, to December, 1982, 29 PTFE shunts were performed. There were no hospital deaths or shunt failures. Catheterization was performed in 14 patients from 2 months to 2.5 years (mean 13.4 months) following operation. All shunts were patent. Arterial Po2 at the late study ranged from 33 to 96 torr (mean 57.1 +/- 17.3 torr) and was not significantly different from values obtained before hospital discharge at the time of the shunt procedure (mean 47.6 +/- 5.9 torr). Only one patient demonstrated moderate pulmonary hypertension (44/25 mm Hg), believed to be secondary to ventricular dysfunction. No patient demonstrated pulmonary artery distortion or kinking, and none required a second shunt because of inadequacy of the original procedure. The results in these patients, as well as the continued excellent clinical course of the patients not as yet recatheterized, have prompted us to use this shunt as our procedure of choice in neonates.