Manual thrombus aspiration during primary percutaneous coronary intervention: Impact of total ischemic time

Background The benefit of manual thrombus aspiration (TA) during primary percutaneous coronary intervention (PCI) remains uncertain, and the effect of TA in relation to total ischemic time has not been evaluated. Methods We analyzed 5641 patients with ST-elevation myocardial infarction (STEMI) (<12 h) from the Korea Acute Myocardial Infarction Registry undergoing primary PCI. Patients were divided into 2 groups: TA (n = 1245) and PCI only (n = 4396). Propensity-matched 12-month clinical outcome was compared between the groups according to different total ischemic times (≤2 h, 2–4 h, 4–6 h, >6 h). Results Twelve-month rates of death and major adverse cardiac events (MACE: composite of death, recurrent myocardial infarction, target-vessel revascularization, and coronary artery bypass grafting) were not different between TA and PCI only. After propensity matching (n = 1162 for each group), there were no differences in the 12-month outcome between TA and PCI only, which was consistent across subgroups. In the propensity-matched cohort, the effect of TA on 12-month outcome showed a U-shaped relationship with longer total ischemic time: TA in patients with total ischemic time between 4 and 6 h was associated with lower rates of death [hazard ratio (HR): 0.53, 95% confidence interval (CI): 0.24–1.19, p for interaction = 0.01] and MACE (HR: 0.28, 95% CI: 0.12–0.66, p for interaction = 0.01). Conclusions Manual TA during primary PCI was not associated with improved clinical outcome at 12 months. The impact of TA may become clinically relevant with longer total ischemic time, forming a U-shaped relationship.