Objective: The culprit lesion morphology at acute myocardial infarction (AMI) and unstable angina pectoris (UAP) was investigated by observing the responsible vessels through intravascular ultrasound (IVUS) during the acute stage.
Methods: As the subjects of study, 54 lesions of 54 ACS patients (26 in AMI patients, 28 in UAP patients) were enrolled prospectively from June 1994 to June 1998. The appearance of plaque in the lesion, the distal and proximal sites, extent of calcification, eccentricity, remodeling and shrinkage were observed through IVUS before the intervention.
Results: At lesion and distal site, significantly more soft plaques were observed in AMI than UAP. As to the extent of calcification in the former, mild calcification was noted significantly more in distal site as well as a tendency of more mild calcification in the lesion and proximal site.
Conclusion: These results suggested that the condition of responsible coronary artery is involved in the onset mechanism of AMI and UAP.