Coronary occlusion: cause or consequence of acute myocardial infarction?

A 45-year-old man with unstable angina developed persistent ECG changes of myocardial ischemia during coronary angiography. Occlusion of the left anterior descending branch (LAD) was documented 20 minutes after these changes. Intracoronary nitrate, Ca antagonist, urokinase, removal by percutaneous transluminal coronary angioplasty (PTCA) of atherosclerotic obstructions, and emergency bypass surgery failed to restore myocardial perfusion. Only short periods of reflow were obtained by urokinase and PTCA. The repeated coronary injections demonstrated a progressive disappearance of the left anterior descending artery (LAD) starting from the distal portion and progressing retrogradely up to the origin of the vessel. The patient developed a transmural anterolateral myocardial infarction and 12 months later underwent cardiac transplantation for untractable failure. His heart was examined and the infarct confirmed. Analysis of this case suggests that coronary occlusion in acute myocardial infarction can be an event secondary to increased intramyocardial resistance rather than the cause of reduced coronary blood flow in subepicardial coronary arteries.