Association of virtual histology characteristics of the culprit plaque with post-fibrinolysis flow restoration in ST-elevation myocardial infarction

Abstract

ObjectivesWe sought to test the hypothesis that virtual histology characteristics of the culprit lesion in patients with ST-elevation myocardial infarction are associated with blood flow restoration after thrombolysis. MethodsConsecutive patients referred for coronary angiography after successful thrombolysis were included in this correlational cross-sectional study. Evaluation with intravascular ultrasound (IVUS) and virtual histology of the culprit arterial segment was performed in all cases. ResultsForty-eight patients (60.5±10.7years) were included. TIMI flow grade 3 was found in 24 (50%). Diabetes was strongly associated with lower TIMI flow 3 rate (26.7% vs 60.6%; p=0.029) and there was a significant difference in the time to thrombolysis (2.0±0.8hours in those with TIMI flow 3 vs 3.0±0.7hours in TIMI flow grades 1–2; p<0.001). Patients with TIMI flow grades 3 and 1–2 had similar absolute total plaque volume (152.8±59.3mm3 vs 147.5±92.3mm3; p=0.817) and absolute necrotic core (NC) volume (31.2±13.9mm3 vs 33.6±23.2mm3; p=0.671). However, there were significant differences in the relative NC content, both in proportion to the whole plaque volume (26.3% vs 29.9%; p=0.016) and as an area fraction at the largest NC site (31.5% vs 40.3%; p<0.001). ConclusionThe NC content of atherosclerotic plaques is meaningful for flow restoration after the occurrence of a coronary event. This finding highlights the importance of plaque composition, as studied with virtual histology, not only for the sequence of processes leading to an acute plaque-related event, but also for thrombus formation and lysis, following the occurrence of such an event.