Effect of Macroscopic-Positive Thrombus Retrieval During Primary Percutaneous Coronary Intervention With Thrombus Aspiration on Myocardial Infarct Size and Microvascular Obstruction

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.