1120-41 Relationship of ultrasound plaque characteristics to thrombolysis in myocardial infarction myocardial perfusion grade following intracoronary stenting

Background: There is conflicting evidence for the link between calcification and plaque instability. Intravascular ultrasound (IVUS) studies have shown that calcified plaques are associated with stable plaques. In contrast, recent histopathological studies have revealed that plaque calcification is present in 69% of ruptured plaques in sudden coronary death. Furthermore, studies using electron-beam computed tomography have reported that calcium score relates to acute coronary events. The purpose of this study is to investigate the relationship between patterns of calcification and arterial remodeling of culprit lesions, comparing patients with acute coronary syndromes (ACS) with those with stable angina (SAP). Methods and Results: Preinterventional intravascular ultrasound (IVUS) images of 178 patients were studied; 61 with acute myocardial infarction (AMI), 70 with unstable angina pectoris (UAP) and 47 with SAP. The presence of calcifications within an arc of less than 90° for all calcifications was significantly higher in patients with either AMI or UAP than in SAP (P<0.0001). Moreover, the average number of calcium deposits within an arc of less than 90° per patient was significantly higher in AMI than in SAP (P<0.0005) (AMI: 1.4±1.3, SAP: 0.5±0.8, mean±SD). Conversely, the length of the calcium deposits was significantly longer in SAP patients (P<0.0001) (AMI: 2.2±1.6, UAP: 1.9±1.8, SAP: 4.3±3.2, mean±SD). In AMI patients, the typical pattern was spotty calcification, associated with a fibrofatty plaque and positive remodeling. In ACS patients showing negative remodeling, no calcification was the most frequent. Conversely, in SAP patients, the frequency of extensive calcification was the highest. Conclusion: These findings show that IVUS allows the identification of vulnerable plaques in coronary arteries, not only by identifying a large lipid core and positive remodeling, but also by identifying a spotty pattern of calcification.