921-75 Restenosis After Pulmonary Artery Angioplasty

Abstract

The expanding role of combined catheter and surgical therapies for complex congenital cardiac defects has led to wider application of pulmonary artery (PA) angioplasty. However remarkably little information is available on the fate of previously dilated pulmonary arteries. We undertook this study to determine the frequency and predictabilityof restenosis after PA angioplasty. All PA dilations performed from 1/90 to 12/93 at Children's Hospital were reviewed to determine initial success (a. ≥ 50% increase in stenosis diameter; b. >20% decrease in the ratio of right ventricular to aortic pressure (intact ventricular septum); or C. ≥ 20% increase in lung perfusion). Initial and followup up catheterization data for successful dilations (based on angiogra phic criteria only) were then reviewed to determine patient age and diagnosis; etiology of stenosis; balloon size, type, inflation pressure; complications; and diameters of the stenosis and distal vessel pre and post dilation, and at followup. Univariate analyses were performed by Student t-test or one-tailed analysis of correlation coefficients. Significance was set at P ≤ 0.05. Seventy-three percent of 59 dilations performed in 29 patients at a median age of 2.5 y (range 6 m to 32 y) were successful. Based on angiographic measurements alone, 37 were successful; this group was subjected to further analysis. Followup catheterizations were performed in 21 of 37 cases (57%l a mean of 7 ± 6 m after dilation. No significant differences in patient or procedure characteristics were present between cases with and without followup studies except the latter had undergone dilation more recently (p = 0.02). Followup angiograms demonstrated some degree of restenosis in > 60% of cases. Based on standard criteria (> 50% loss in initial gain) significant restenosis occurred in 11 of 21 vessels (52%). Neither risk nor severity of restenosis correlated significantly with any patient or procedure characteristics reviewed (see methods). Of note, there was no correlation between restenosis and the interval between the initial dilation and followup angiogram. Significant restenosis is common early after pulmonary artery dilation. In this small series we were unable to identify any factors predicting subsequent restenosis. Future study should be directed at identifying mechanisms and predictors of restenosis after pulmonary angioplasty. All patients undergoing successful pulmonary artery dilation require followup angiography.