The impact of initial and residual thrombus burden on the no-reflow phenomenon in patients with ST-segment elevation myocardial infarction

BACKGROUND Limited data are available on the clinical significance of residual thrombi after thrombectomy and prestenting reduced epicardial coronary flow in ST-segment elevation myocardial infarct (STEMI) patients. MATERIALS AND METHODS The incidence of the no-reflow phenomenon, defined as a final thrombolysis in myocardial infarction (TIMI) flow grade of up to 2 or a myocardial blush grade of up to 1, was compared in 260 STEMI patients undergoing primary percutaneous coronary intervention according to thrombotic burden. Large thrombotic burden (LTB), defined as a thrombus score of at least 3, was observed in 134 patients, among whom 66 (49.3%) underwent aspiration thrombectomy. No-reflow incidence was compared on the basis of thrombectomy treatment, thrombus residue after thrombectomy, and prestenting TIMI flow grade. RESULTS The no-reflow phenomenon occurred most frequently in LTB patients without thrombectomy, followed by those who underwent thrombectomy and the small thrombus burden group (33.8 vs. 21.2 vs. 10.3%, respectively, P