Intracoronary morphology of culprit lesions after reperfusion in acute myocardial infarction: serial angioscopic observations

Abstract

Objective: This study sought to elucidate the morphologic and pathologic characteristics of culprit lesions in patients with acute myocardial infarction.

Background: The pathogenic mechanisms of acute myocardial infarction have been discussed on the basis of postmortem histologic examinations. Disruption of lipid-rich plaques is thought to render them thrombogenic. However, the details of coronary morphology have not been elucidated in survivors of myocardial infarction. The quality of angioscopic images has been greatly improved, and clear visualization of the intracoronary milieu can now be obtained.

Methods: Eleven patients with acute myocardial infarction and angiographic demonstration of the culprit lesion were entered into the study. Angioscopic observations were made immediately after reperfusion and at 1-month follow-up.

Results: Angioscopic observations were successfully performed in 10 patients immediately after reperfusion and in 10 at 33 +/- 26 (mean +/- SD) days of follow-up. Immediately after reperfusion, red thrombus, white thrombus, yellow plaques and intimal flaps were recognized in 30% (95% confidence interval [CI] 25.7 to 35.7), 100%, 100% and 50% (95% CI 45.0 to 55.0) of patients, respectively. At follow-up, these were recognized in 10% (95% CI 6.6 to 16.4), 60% (95% CI 54.6 to 64.7), 100% and 40% (95% CI 35.3 to 45.4) of patients, respectively.

Conclusions: The thrombus in acute myocardial infarction was always recognized over the yellow plaques. The thrombus formed directly over the plaque was mainly white. Red thrombus might be formed after the blood flow was obstructed by the white thrombus. At approximately 1 month, yellow plaques remained in all patients, and > 50% still had adherent white thrombus.