coronary occlusion, an obstruction of an artery that supplies the heart muscle. When complete, it causes myocardial infarction; when incomplete, it may cause angina. The underlying pathophysiological characteristic is atherosclerotic plaque, which usually develops slowly by buildup of lipid and macrophage complexes. Rapid plaque accumulation is frequently caused by hemorrhage within a plaque. If the plaque ruptures, platelets aggregate, fibrin is deposited, spasm occurs, and a thrombus develops, resulting in acute myocardial infarction. Treatment includes prompt IV thrombolysis and administration of heparin. Primary percutaneous transvenous coronary angioplasty can achieve prompt reperfusion. See also coronary artery disease.
