Frequency of restenosis after balloon pulmonary arterioplasty and its causes

Restenosis has been described after balloon pulmonary arterioplasty (BPA), but little is known about its frequency, settings, and time course. We undertook this study to (1) determine the incidence of restenosis after BPA, and (2) identify its potential determinants. We reviewed clinical data and measured pulmonary artery diameters from angiograms of 134 dilations on 75 patients (median 2.1 years, range 0.3 to 32) who had BPA from January 1990 to June 1998. Successful BPA was defined as a ≥50% increase in predilation diameter, whereas restenosis was said to occur if there was a ≥50% loss in initial diameter gain. The success rate after BPA by angiographic criteria was 64% (95% confidence interval 56% to 73%). Seventy-four percent of BPAs were successful by published standard criteria (angiographic criteria or ≥20% change in right ventricular/aortic pressure). Baseline demographic variables and predilation parameters were not predictive of initial dilation success. Restenosis occurred in 35% (95% confidence interval 22% to 49%) of successfully dilated vessels. Only weight at follow-up (p = 0.02) was associated with an increased likelihood of restenosis. Predilation parameters, technical aspects of dilation, or immediate results of BPA were not predictive of restenosis. We therefore conclude that restenosis is unpredictable and more common after BPA than previously recognized.