Koon-Hou Mak

Objective: Oral direct thrombin and anti-Xa inhibitors have been shown to be efficacious in the prevention and treatment of venous thromboembolism, and prevention of embolic events in atrial fibrillation. Recent studies showed that dabigatran may be associated with increased rates of myocardial infarction (MI). Coronary risk for the other agents was unclear. The aim of the study is to determine the coronary risk among four novel antithrombotic agents.Design: Mixed treatment comparison meta-analysis.Data sources and study selection: Randomised controlled trials (RCTs) on ximelagatran, dabigatran, rivaroxaban and apixaban were obtained from PubMed search (February 2012) and major scientific meeting in 2011. The random-effects model was used to evaluate the effect of these agents on MI or acute coronary syndrome (MI/ACS), major bleeding complication and all-cause mortality.Results: From 28 RCTs (n=138 948), the risk for MI/ACS was higher for dabigatran (OR 1.30; 95% CI 1.04 to 1.63; p=0.021) but lower for rivaroxaban (OR 0.78; 95% CI 0.69 to 0.89; p<0.001). Ximelagatran showed a higher risk for MI/ACS, which was not statistically significant, while apixaban demonstrated a non-significant lower likelihood. Among the RCTs for MI/ACS among the four agents, only those pertaining to ximelagatran showed heterogeneity. Major bleeding complication rates varied considerably among different agents. Importantly, these agents were associated with a lower all-cause mortality, without heterogeneity among the studies.Conclusions: The risk for coronary events was significantly higher for dabigatran but not significantly higher for ximelagatran. Conversely, this risk was lower among anti-Xa inhibitors. All-cause mortality was lower among those receiving novel antithrombotic agents. This information may be useful in selecting agents for specific subsets of patients requiring anticoagulation.

We aimed to determine the relationship between body mass index (BMI) and cardiovascular events among individuals with or at-risk of atherothrombotic disease. This was a prospective observational study of 15 532 patients enrolled in the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) trial who were randomly assigned to clopidogrel or placebo, and followed-up for a median of 28 months for the occurrence of the primary endpoint (cardiovascular death, myocardial infarction, or stroke), all-cause mortality, and bleeding complications. Compared with the highest BMI quartile, the primary endpoint, cardiovascular, and all-cause mortality all occurred more frequently among patients in the lowest BMI quartile (about a third lower). The relationship between continuous BMI and adverse cardiovascular outcomes were presented as two linear spline terms with 29 kg/m² as the cut-point for all-cause mortality. Lower BMI was associated with an increase in moderate and severe bleeding complications, largely accounted for by those receiving dual-antiplatelet agents with the highest tertile aspirin dose. Adverse cardiovascular events and bleeding complications occurred more frequently among individuals with or at-risk for atherothrombotic disease and low BMI. Further studies should be directed to these patients to improve outcomes. The CHARISMA trial is registered with ClinicalTrials.gov, NCT00050817.