[Risk factors for later restenosis after successful coronary angioplasty: Mitsui Memorial Hospital experience].

To determine the risk factors for restenosis, 170 patients with 245 stenotic lesions who underwent follow-up coronary angiography after successful coronary angioplasty (PTCA) were evaluated. The mean angiographic follow-up period was 116 +/- 39 days (+/- SD). Restenosis was defined according to 3 criteria: 1) greater than or equal to 50% loss of the gain achieved by PTCA, 2) greater than or equal to 60% stenosis at follow-up, 3) greater than or equal to 30% increase in stenosis from post-PTCA. The rate of restenosis was 41.2% by criterion 1), 32.2% by criterion 2) and 34.3% by criterion 3). By univariate analysis of 12 clinical, 9 angiographic and 8 procedural factors, 6 factors were significantly associated with restenosis: 1) left anterior descending artery, 2) severe stenosis before PTCA, 3) long lesions, 4) calcified lesions, 5) maximal inflation pressure greater than or equal to 100 psi, 6) number of inflations greater than or equal to 6 times. No clinical factors were suggested to have significant influence on restenosis. Multivariate analysis (stepwise method) revealed independent 6 factors related to restenosis in the following order of importance: 1) number of inflations, 2) maximal inflation pressure, 3) presence of calcification, 4) vessel dilated at PTCA, 5) diabetes mellitus, 6) lesion length. The residual stenosis had no significant influence on restenosis. This may have been due to a small number (14.7%, 36 lesions) of prominent residual stenoses (greater than or equal to 40%) in this study. The presence or absence of intimal disruptions had no significant influence on restenosis. It was suggested that restenosis after successful PTCA may be influenced mainly by "local factors" related to regions.