In patients with ST-segment elevation myocardial infarction (STEMI) who undergo fibrinolysis, not all achieve normal coronary flow. This study investigated the characteristics of culprit lesion plaques using virtual histology-intravascular ultrasound (VH-IVUS) in relation to baseline TIMI flow. Pre-intervention IVUS was conducted on 61 STEMI patients post-fibrinolysis, divided into TIMI 1–2 flow group (n = 31) and TIMI 3 flow group (n = 30). The study found that the external elastic membrane cross-sectional area (EEM CSA) was higher in the TIMI 1–2 group, while plaque burden and volume were similar between groups. VH-IVUS showed that the TIMI 1–2 group had a higher fibrous area, necrotic core (NC) area, and NC percentage at the minimal luminal area site. The absolute NC volume was significantly higher in the TIMI 1–2 group and was the only independent predictor of TIMI 1–2 flow, with a receiver operating characteristic curve indicating high diagnostic accuracy. The study concludes that the necrotic core component of the culprit lesion is crucial in predicting coronary flow restoration post-fibrinolysis.
