Impact of thromboischemic reentry mechanism of coronary thrombosis and microembolism in acute myocardial infarction.

It has been suggested that the thromboischemic reentry mechanism (TRM) is responsible for washing platelet aggregates out of the coronary vessels during the early phase of acute myocardial infarction (AMI). This might account for the observation of Schwartz, who reported the presence of multiple microthrombi in the subendocardial blood vessels following AMI but found only a few thrombotic occlusions in the main coronary arteries. This washing-out of the vessel (due to reperfusion waves) intermittently releases myoglobin into the serum and is responsible for the "staccato phenomenon." We examined a group of 177 patients with a mean age of 66.1 years, whose sudden death was definitely of cardiac origin. Infarction was confirmed in 84.7% of the subjects (fresh infarct: 23.7%; fresh infarct with scarring: 25.9%; scarring alone: 35.0%; no change in myocardium: 15.2%). In other words, 49.7% of all postmortem subjects (88 cases) showed fresh infarction. Opening the coronary arteries longitudinally revealed only 7 thrombi in these 88 cases, i.e., 7.9% of all fresh infarcts. These observations confirm those of Roberts (8.5%) and Friedmann (4%).