Prognostic Impact of Residual Thrombus After Aspiration Thrombectomy in ST-Elevation Myocardial Infarction.

BACKGROUND: The prognostic significance of residual thrombus volume after aspiration thrombectomy in patients with ST-segment elevation myocardial infarction (STEMI) remains unclear. OBJECTIVES: The authors aimed to investigate whether residual thrombus volume quantified by post-aspiration optical coherence tomography (OCT) is associated with major adverse cardiovascular events (MACE) in patients with STEMI undergoing primary percutaneous coronary intervention (PCI). METHODS: This retrospective single-center study included 233 patients with STEMI who underwent manual aspiration thrombectomy followed by OCT-guided primary PCI within 12 hours of symptom onset. Residual thrombus volume was quantified at 1.0-mm intervals. The optimal cutoff was determined using maximally selected log-rank statistics. The primary endpoint was MACE, defined as cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Associations with MACE were evaluated using Kaplan-Meier and Cox regression analyses. RESULTS: During a median follow-up of 2.5 years (IQR: 1.3-3.5 years), MACE occurred in 46 patients (19.7%). Patients with residual thrombus volume ≥4.14 mm3 had a higher cumulative incidence of MACE than those with <4.14 mm3 (log-rank P = 0.0018). Residual thrombus volume remained independently associated with MACE as a continuous variable (adjusted HR: 1.014 per 1 mm3 increase; 95% CI: 1.001-1.027; P = 0.031). Similar findings were observed using the 4.14-mm3 cutoff (adjusted HR: 2.95; 95% CI: 1.51-5.74; P = 0.002). CONCLUSIONS: Residual thrombus burden quantified by OCT after aspiration thrombectomy was independently associated with adverse cardiovascular outcomes in patients with STEMI. Quantitative OCT assessment may provide complementary prognostic information for post-PCI risk stratification.