Previous studies reported that reduced TIMI (Thrombolysis in Myocardial Infarction) flow grade before procedure was associated with worse clinical outcomes in patients with ST-segment–elevation myocardial infarction undergoing primary percutaneous coronary intervention. The aim of this study was to identify specific morphological characteristics of the culprit plaque associated with poor TIMI flow grade at baseline in patients with ST-segment–elevation myocardial infarction using both optical coherence tomography and intravascular ultrasound.Methods and Results—
A total of 111 ST-segment–elevation myocardial infarction patients who underwent percutaneous coronary intervention within 24 hours of symptom onset were included. Both optical coherence tomography and intravascular ultrasound were performed after thrombectomy. Patients were divided into 2 groups according to preprocedural TIMI flow grade (TIMI 0–1 [n=82] and TIMI 2–3 [n=29]). Patients with preprocedural TIMI 0 to 1 had a greater lipid arc (P=0.037), a longer lipid length (P=0.021), and a greater lipid index (P=0.007) determined by optical coherence tomography and a larger external elastic membrane cross-sectional area (P=0.030) and plaque plus media cross-sectional area (P=0.030) determined by intravascular ultrasound, compared with patients with preprocedural TIMI 2 to 3.Conclusions—
ST-segment–elevation myocardial infarction patients with reduced TIMI flow grade at baseline have greater lipid burden, larger vessel sizes, and larger plaque areas.