[The CHARISMA study: in search of the best antiplatelet strategy for cardiovascular prevention]

The CHARISMA ("Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance") trial compared the effects of a dual antiplatelet therapy with clopidogrel plus low dose aspirin with those of a monotherapy with aspirin (75-162 mg/day) on the incidence of cardiovascular events in 15,603 patients at high risk for atherothrombotic events followed for a median of 28 months. The primary efficacy endpoint, a composite of myocardial infarction, stroke, or death from cardiovascular causes, was not significantly different between the two treatment arms. The secondary principal efficacy endpoint, which included all hospitalizations for ischaemic events, was slightly reduced in the group with clopidogrel-aspirin as compared to the group with placebo-aspirin. In a subgroup analysis, among so-called "symptomatico" patients (79 % of the studied population), the dual antiplatelet therapy was associated with a significantly lower incidence of events than aspirin alone, including the primary efficacy end point. On the contrary, in "asymptomatic" patients, such a favourable effect was not observed. Unexpectedly, in this subgroup, a paradoxical increase in the mortality rate was observed with the clopidogrel-aspirin combination. As far as safety was concerned, the risk of severe (difference not significant) and moderate (difference significant) bleeding was higher in patients with the clopidogrel-aspirin combination. In conclusion, acetylsalicylic acid (aspirin) is the first choice drug and the only antiplatelet agent to be used in prvention of cardiovascular disease. In secondary prevention, the addition of clopidogrel may reinforce the cardiovascular protection given by aspirin in "symptomatic" patients, but at the expense of a slightly higher bleeding rate.