Adjunctive thrombus aspiration (TA) during primary percutaneous coronary intervention improves myocardial perfusion and survival; however, the effect of effective thrombus retrieval remains unclear. We evaluated whether macroscopic-positive TA in patients with ST-segment elevation myocardial infarction would reduce the infarct size (IS) and microvascular obstruction (MVO), as assessed by contrast-enhanced magnetic resonance imaging. A total of 88 patients with ST-segment elevation myocardial infarction were prospectively recruited and assigned to the TA-positive group (n = 38) or TA-negative group (n = 50) according to whether macroscopic aspirate thrombus was visible to the naked eye. The primary end points were the extent of early and late MVO as assessed by contrast-enhanced magnetic resonance imaging performed during in-hospital stay and IS evaluated in the acute phase and at 6 months of follow-up. The incidence of early and late MVO and IS in the acute phase was lower in the TA-positive group than in the TA-negative group (early MVO 3.8 ± 1.1% vs 7.6 ± 2.1%, respectively, p = 0.003; late MVO 2.1 ± 0.9% vs 5.4 ± 2.9%, p = 0.006; and IS 14.9 ± 8.7% vs 28.2 ± 15.8%, p = 0.004). At the 6-month contrast-enhanced magnetic resonance imaging study, the final IS was significantly lower in the TA-positive group (12.0 ± 8.3% vs 22.3 ± 14.3%, respectively) than in the TA-negative group (p = 0.002). After multivariate adjustment, macroscopic-positive TA represented an independent predictor of final IS (odds ratio 0.34, 95% confidence interval 0.03 to 0.71, p = 0.01). In conclusion, effective macroscopic thrombus retrieval before stenting during percutaneous coronary intervention for ST-segment elevation myocardial infarction is associated with an improvement in myocardial reperfusion, as documented by a clear reduction in the MVO extent and IS.
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