Morphometric analysis of coronary lesions in patients with unstable angina--an arteriographic study.

In 100 patients with unstable angina and 50 patients with stable angina qualitative morphology of coronary artery lesions were compared by angiography. The mean age of the patients was 51 years. In the unstable angina group, 50 patients had rest angina, 32 had crescendo angina and 18 had denovo angina; 31 patients had single vessel disease, 33 had two vessel disease, 34 had triple vessel disease and 2 had left main disease. 'Angina-producing' artery could be identified in 90 out of 100 patients. Ten totally occluded vessels were excluded from analysis. Lesions causing diameter stenosis of greater than 50% could be categorised to one of the following groups: a) Concentric stenosis (18 vessels), b) Type I eccentric lesion (asymmetric narrowing with smooth borders and broad neck--20 vessels), c) Type II eccentric lesion (asymmetric narrowing with narrow neck and overhanging irregular edges--47 vessels), and d) Multiple irregularities (15 vessels). Lesions in 9 vessels showed an associated thrombus. It appears that Type II eccentric lesions are frequent in patients with unstable angina; they probably represent ruptured atherosclerotic plaque or partially occlusive thrombi or both.