COMPARISON OF CORONARY ANGIOGRAPHIC NARROWING IN STABLE ANGINA-PECTORIS, UNSTABLE ANGINA PECTORIS, AND IN ACUTE MYOCARDIAL-INFARCTION

Coronary angiographic findings were compared In patients who presented with acute myocardial infarction (AMI, n = 75), unstable angina pecto ris (UAP, n = 36), or stable angina pectoris (SAP, n = 36) for greater than or equal to 2 years without evidence of any previous acute event and with an angiogram within 2 years of the initial symptoms. Angiogr ams were evaluated blindly for severity, extent (depending on the perc entage of each coronary segment showing atherosclerosis), and pattern (discrete, <3 loci of narrowings involving <50% of any segment; diffus e, anything exceeding this). Patients in the SAP group had more narrow ed arteries (2.4 +/- 0.7 vs 1.3 +/- 0.6 [p <0.02] and 1.4 +/- 0.6 [p < 0.02]), more stenoses (6.0 +/- 3.3 vs 2.1 +/- 1.5 [p <0.01] and 2.6 +/ - 1.7 [p <0.05]) and occlusions (1.3 +/- 1.1 vs 0.7 +/- 0.6 [p = 0.05] and 0.3 +/- 0.5 [p <0.02]), and a greater extent index (0.9 +/- 0.5 v s 0.5 +/- 0.3 [p <0.02] and 0.5 +/- 0.3 [p <0.02] than those in the AM I and UAP groups. Furthermore, a discrete pattern was less prevalent i n patients with UAP than in those with SAP or AMI (3% vs 40% [p <0.02] and 25% [p <0.05], respectively). In conclusion, patients who present with acute coronary syndromes have less extensive atherosclerosis tha n those who present with chronic stable angina. Therefore. in the form er group, coronary atherosclerosis appears to be more susceptible to i schemic stimuli responsible for acute coronary syndromes. Conversely, whether acute ischemic stimuli result in AMI or in UAP does not appear to depend on the severity of coronary atherosclerosis.