Does Residual Thrombus After Aspiration Thrombectomy Affect the Outcome of Primary PCI in Patients With ST-Segment Elevation Myocardial Infarction?: An Optical Coherence Tomography Study

The aim of this study was to evaluate if residual thrombus burden after aspiration thrombectomy affects the outcomes of primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction (STEMI). Recent studies failed to show clinical benefit of aspiration thrombectomy in STEMI patients. This might be due to insufficient removal of thrombus at the culprit lesion. A total of 109 STEMI patients who underwent aspiration thrombectomy followed by stenting within 24 h from symptom onset were included. Optical coherence tomography was performed after thrombectomy to measure residual thrombus burden. Patients were divided into tertiles based on the amount of residual thrombus and the outcomes were compared. Myocardial no reflow, defined as TIMI (Thrombolysis In Myocardial Infarction) flow grade of ≤2 and/or myocardial blush grade of ≤1 after stenting, was more observed frequently in patients in the highest tertile compared with those in the lowest tertile (44.4% vs. 16.7%; p = 0.001). Patients in the highest tertile also had greater myocardial damage measured by creatine kinase MB compared with those in the lowest tertile (p = 0.002). STEMI patients with greater residual thrombus burden after aspiration thrombectomy had worse microvascular dysfunction and greater myocardial damage compared with those with smaller residual thrombus burden.