[Myocardial infarction caused by acute left main coronary artery occlusion. Apropos of 4 cases and review of the literature].

Between 1979 and 1996, 4 acute occlusions of the left main coronary artery (LMC) were treated by primary transluminal coronary angioplasty. They were 4 men with a mean age of 43 +/- 5 years, admitted to hospital less than 8 hours after the clinical onset of symptoms of anterior myocardial infarction in Killip class 4 with complete right bundle branch block on the initial electrocardiogramme. All cases had a previous history of unstable angina over 2 to 15 days. Angioplasty was undertaken immediately in view of the haemodynamic instability. The coronary circulation was of a dominant right coronary type in the 4 cases: significant stenoses were discovered after recanalisation, on the left anterior descending artery (LAD) in 2 cases and the circumflex or marginal arteries in 3 cases. The right coronary artery was atheromatous in all cases but without significant stenosis. Angioplasty was completed by implantation of a stent in 3 cases (LAD : 1 case, LMC : 2 cases). The outcome was rapidly fatal in 3 cases. Only one patient survived 6 months in functional class 3. These results show that myocardial infarction due to occlusion of the left main coronary artery is a very severe condition which justifies rapid recanalisation. Primary angioplasty with stent implantation in an immediate therapeutic option which enables the patient to survive the acute stage, though only in a limited number of cases.