An analysis of outcome following percutaneous transluminal coronary artery angioplasty. An autopsy series. We analyzed autopsy findings on 26 patients who died following percutaneous transluminal coronary angioplasty (PTCA). Twenty-one patients died within 3 weeks of undergoing PTCA; demonstrable cardiac complications were found in 19 patients: platelet-fibrin thrombi (10 patients [48%]), coronary artery dissections (17 patients [81%]), thromboemboli (13 patients [62%]), atheroemboli (seven patients [33%]), and myocardial infarcts (17 patients [81%]). An increased incidence of coronary platelet-fibrin thrombi was noted when compared with a non-PTCA cardiac autopsy population (five of 53 patients). Apparently there was an increased incidence of coronary atheroemboli and thromboemboli in the patients with coronary platelet-fibrin thrombi (eight patients) when compared with patients who did not have platelet-fibrin thrombi (five patients), although this was not statistically significant. There was no evidence of a systemic hypercoagulable state or of disseminated intravascular coagulation. The pathogenesis of this is unclear; however, vasospasm and a disruption of the endothelial surface induced by PTCA with subsequent platelet activation are possible causes. Although not statistically significant, there was a proponderance of female subjects (seven patients) and an increased incidence of diabetes mellitus (six patients) and hypertension (13 patients) when compared with a control population of all patients undergoing PTCA at The Cleveland (Ohio) Clinic Foundation in 1987, suggesting that diabetes mellitus, hypertension, and female sex may be clinical risk factors for fatal complications following PTCA. 