Is preinfarction angina related to the presence or absence of coronary plaque rupture?

Objective-To analyse the prodrome of acute myocardial infarction in relatio n to the plaque morphology underlying the infarct. Design-A retrospective investigation of the relation between rupture and er osion of coronary atheromatous plaques and the clinical characteristics of acute myocardial infarction. The coronary arteries of 100 patients who died from acute myocardial infarction were cut transversely at 3 mm intervals. Segments with a stenosis were examined microscopically at 5 mu m intervals. The clinical features of the infarction were obtained from the medical rec ords. Results-A deep intimal rupture was encountered in 81 plaques, whereas 19 ha d superficial erosions only. There were no differences in the location of i nfarction, the incidence of hypertension, diabetes mellitus, or hyperlipida emia, diameter stenosis of the infarcted related artery, Killip class, Forr ester's haemodynamic subset, or peak creatine kinase between plaque rupture and plaque erosion groups. The presence of plaque rupture was associated w ith significantly greater incidences of leucocytosis, current smoking, and sudden or unstable onset of acute coronary syndrome. In patients with unsta ble preinfarction angina, new onset rest angina rather than worsening angin a tended to develop more often in the plaque rupture group than in the plaq ue erosion group (p = 0.08). Conclusions-Plaque rupture causes the sudden onset of acute myocardial infa rction or unstable preinfarction angina, which may be aggravated by smoking and inflammation.