Intimal tear or dissection is an important descriptor of ischemic complications after coronary angioplasty, but only the minority of patients will develop an acute ischemic event. To identify additional factors that may predict the development of an ischemic event when arterial disruption occurs during otherwise uncomplicated angioplasty, the records of 1,346 patients prospectively identified as having tear or dissection without immediate vessel closure were examined. Ischemic complications, defined as ischemic chest pain, myocardial infarction, the need for coronary bypass surgery, or death, occurred in 120 patients (9%). Significant multivariate correlates of an ischemic complication were the presence of unstable angina or a totally occluded vessel before angioplasty and diameter stenosis of greater than 30% after angioplasty. Detailed geometric and videodensitometric analysis of the postdilatation angiograms of a subset of 96 consecutive patients was carried out. Ischemic complications occurred in 11 patients (11%). Multivariate analysis revealed that the independent correlates of complications, in decreasing order of importance, were the length of the tear or dissection (p = 0.001), diameter stenosis after angioplasty (p = 0.001), cross-sectional area after dilatation measured by videodensitometric methods (p = 0.013), and the presence of extraluminal contrast (p = 0.044). When tear or dissection occurs during otherwise uncomplicated coronary angioplasty, patients at risk of developing delayed ischemic complications can be identified and may benefit from measures designed to minimize this risk. By controlling for the geometric or mechanical factors that result in tear or dissection, it has been possible to identify factors not previously thought associated with ischemic complications.(ABSTRACT TRUNCATED AT 250 WORDS)