Prognostic impact of clopidogrel pretreatment in patients with acute coronary syndrome managed invasively.

Pretreatment with antiP2Y12 agents before angiography in acute coronary syndrome (ACS) is associated with a reduction in thrombotic events. However, recent evidences have questioned the benefits of upstream antiP2Y12, reporting a higher incidence of bleeding. We analyzed the prognostic impact of clopidogrel pretreatment in a large cohort of invasively managed patients with ACS. In hospital, safety and efficacy of clopidogrel pretreatment were retrospectively analyzed in patients included in the ARIAM-Andalucía Registry (Analysis of Delay in Acute Myocardial Infarction). Propensity score and inverse probability of treatment weighting analysis were performed to control treatment selection bias. Results were stratified by ACS type. Sensitivity analyses were used to explore stability of the overall treatment effect. Of 9,621 patients managed invasively, 69% received clopidogrel before coronary angiography. In the ST-elevation myocardial infarction group, pretreatment was associated with a significant reduction in reinfarction (odds ratio 0.53, 95% confidence interval [CI] 0.27 to 0.96; p = 0.027), stent thrombosis (odds ratio 0.15, 95% CI 0.06 to 0.38; p <0.0001), and mortality (odds ratio 0.67, 95% CI 0.48 to 0.94; p = 0.020), with an increase in minor bleeding but remained as a net clinical benefit strategy. Those benefits were not present in patients without ST elevation (non-ST elevation ACS). The weighting and propensity analysis confirmed the same results. An interaction between pretreatment duration and bleeding was observed. In conclusion, pretreatment with clopidogrel reduced the occurrence of death and thrombotic outcomes at the cost of minor bleeding. Those benefits exclusively affected ST-elevation myocardial infarction cases. The potential benefit of routine upstream pretreatment in patients with non-ST-elevation ACS should be reappraised at the present.