Is there an association between aspirin dosing and cardiac and bleeding events after treatment of acute coronary syndrome? A systematic review of the literature.

BACKGROUND: Current acetylsalicylic acid (ASA) dosing algorithms for the prevention of secondary thrombotic events in acute coronary syndrome (ACS) patients are inconsistent and lack sufficient data support.

METHODS: We performed a systematic review of the literature for studies that assessed clinical outcomes in patients with ACS following coronary stent insertion (SI) or medical treatment (MT). Acetylsalicylic acid dosing was stratified into low- (<160 mg) and high- (≥ 160 mg) dose categories. Outcomes were assessed at 1, 6, and 12 months and included major bleeding, myocardial infarction, and all-cause death. A random-effects meta-analysis was used to estimate the value of the mean for each outcome variable.

RESULTS: Of 12,472 publications identified, 136 studies with 289,330 patients were analyzed. In the 1-month SI analysis, proportions of patients (95% CI) in the low- and high-dose ASA categories experiencing major bleeding were 2.1% (1.5-2.6) and 1.9% (0.0-3.8); proportions with myocardial infarction were 2.1% (1.3-2.8) and 1.8% (0.9-2.6); and proportions of all-cause death were 2.8% (2.2-3.4) and 2.4% (1.3-3.5), respectively. Results were similar in the MT analysis, except that major bleeding rates for low and high doses were 1.7% (1.3-2.2) and 4.0% (2.2-5.8), respectively. Regression analyses suggested that the proportion of patients reporting each of the outcomes evaluated were not significantly different between the low- and high-dose categories, with the exception of the 1-month major bleeding following MT.

CONCLUSIONS: Our results suggest no improved clinical outcomes associated with higher ASA maintenance doses in ACS patients receiving SI or MT. In the MT analysis, there was more major bleeding in the first month after an ACS event with high-dose ASA.