Thrombus aspiration in ST elevation myocardial infarction: comparative efficacy in patients treated early and late after onset of symptoms

BACKGROUND: Restoration of myocardial perfusion is the goal of percutaneous coronary intervention (PCI) in patients with ST elevation myocardial infarction. A major predictor of no-reflow is the increasing time to treatment (TTT). Thrombus aspiration (TA) is reported to improve myocardial reperfusion as compared with standard PCI (SP). OBJECTIVE: To investigate the influence of TTT on TA efficacy. DESIGN: Pooled analysis of individual patients' data of three prospective randomised trials comparing TA and SP. PATIENTS: A total of 299 patients (150 in TA group and 149 in SP group) entered the study. The study population was divided into three subgroups according to the TTT: < or = 3 h (short TTT subgroup), >3 h to < or = 6 h (intermediate TTT subgroup), >6 h to < or = 12 h (long TTT subgroup). MAIN OUTCOME MEASURES: The goal of the study was the comparison of optimal myocardial reperfusion, defined as the combination of myocardial blush grade 2 or 3 at post-PCI angiography and ST resolution more than 70% at post-PCI ECG, between SP and TA according to TTT. RESULTS: In the SP group, increasing TTT was associated with a decreased rate of optimal reperfusion (27.4% vs 17.9% vs 10%, p for trend=0.06), whereas in the TA group the same trend was not seen (40.9% vs 33.8% vs 50%, p for trend=0.93). In a multivariate logistic regression model, a significant interaction (p=0.04) between time to treatment and thrombus aspiration was observed. CONCLUSIONS: TA limits the adverse effects of TTT prolongation on myocardial reperfusion.