Effect of chronic Aspirin therapy on angiographic thrombotic burden in patients admitted for a first ST-elevation myocardial infarction.

Myocardial no-reflow may negate the benefit of urgent coronary revascularization in patients with acute ST-elevation myocardial infarction (STEMI). Among its pathogenetic mechanisms, distal embolization is of prominent importance and several studies have shown that a high coronary thrombotic burden is associated with distal embolization. We aimed at assessing predictors of angiographic thrombus grade in patients undergoing primary percutaneous coronary intervention. Ninety-one patients (62 +/- 12 years old, 79% men) presenting for a first STEMI and undergoing urgent coronary angiography within 12 hours from onset of symptoms were consecutively included in the study. Thrombus grade was evaluated by angiography according to the Gibson score and patients were allocated to the high thrombus grade (HTG; score 4 to 5) group or to the low thrombus grade (score 0 to 3) group. Variables predicting angiographic thrombus grade were assessed among clinical, angiographic, procedural, and laboratory data. Sixty-four patients (61 +/- 12 years old, 78% men) presented with HTG, whereas 27 patients (63 +/- 10 years old, 80% men) presented with low thrombus grade. Patients an HTG showed a significantly higher white blood cell count (12.5 +/- 4.8 vs 10.5 +/- 2.9, p = 0.015). Aspirin and beta-blocker therapy before admission were less frequently taken in the HTG group (5% vs 26% and 7% vs 23%, respectively, p = 0.01 and p = 0.03). At multivariate analysis, lack of previous therapy with aspirin was the only independent predictor of an HTG (odds ratio 6.14, 95% confidence interval 1.09 to 34.67, p = 0.04). In conclusion, previous aspirin therapy is associated with a decrease in angiographic thrombus grade in patients with STEMI treated with primary percutaneous coronary intervention, thus further priming efforts for appropriate use of aspirin in primary prevention of a first STEMI.