Culprit lesion plaque characterization and thrombus grading by high‐definition intravascular ultrasound in patients with ST‐segment elevation myocardial infarction

Background Dedicated prospective studies investigating high‐definition intravascular ultrasound (HD‐IVUS)‐guided primary percutaneous coronary intervention (PCI) are lacking. The aim of this study was to qualify and quantify culprit lesion plaque characteristics and thrombus using HD‐IVUS in patients presenting with ST‐segment elevation myocardial infarction (STEMI). Methods The SPECTRUM study is a prospective, single‐center, observational cohort study investigating the impact of HD‐IVUS‐guided primary PCI in 200 STEMI patients (NCT05007535). The first 100 study patients with a de novo culprit lesion and a per‐protocol mandated preintervention pullback directly after vessel wiring were subject to a predefined imaging analysis. Culprit lesion plaque characteristics and different thrombus types were assessed. An IVUS‐derived thrombus score, including a 1‐point adjudication for a long total thrombus length, long occlusive thrombus length, and large maximum thrombus angle, was developed to differentiate between low (0–1 points) and high (2–3 points) thrombus burden. Optimal cut‐off values were obtained using receiver operating characteristic curves. Results The mean age was 63.5 (±12.1) years and 69 (69.0%) patients were male. The median culprit lesion length was 33.5 (22.8–38.9) mm. Plaque rupture and convex calcium were appreciated in 48 (48.0%) and 10 (10.0%) patients, respectively. Thrombus was observed in 91 (91.0%) patients (acute thrombus 3.3%; subacute thrombus 100.0%; organized thrombus 22.0%). High IVUS‐derived thrombus burden was present in 37/91 (40.7%) patients and was associated with higher rates of impaired final thrombolysis in myocardial infarction flow (grade 0–2) (27.0% vs. 1.9%, p