Anticoagulant linked to increased risk for acute coronary events

Uchino K. Arch Intern Med. 2012;doi:10.1001/archinternmed.2011.1666.

Issue: February 25, 2012

The anticoagulant dabigatran is associated with an increased risk for myocardial infarction or acute coronary syndrome in a wide range of patients when compared with other medicines, according to a study published online in the Archives of Internal Medicine.

Originally FDA-approved in 2010 for the prevention of stroke and systemic embolism in those with nonvalvular atrial fibrillation, dabigatran etexilate (Pradaxa, Boehringer Ingelheim) was later compared with warfarin in a 2-year safety and efficacy study of 18,000 patients with atrial fibrillation. Although the trial reported a decrease in stroke and systemic embolism for patients receiving dabigatran, there also was an increased risk for MI.

In 2011, Ken Uchino, MD, and Adrian V. Hernandez, MD, PhD, of the Cleveland Clinic in Ohio, reviewed PubMed, Scopus and Web of Science for randomized controlled trials of dabigatran in which MI or acute coronary syndrome were reported as secondary outcomes.

Seven trials were selected for the meta-analysis — comprising 30,514 participants — including three studies in short-term prophylaxis of deep venous thrombosis, two studies of stroke prophylaxis in atrial fibrillation, one study in acute venous thromboembolism and one study in acute coronary syndrome. Compared against control groups administering warfarin, enoxaparin or placebo, dabigatran was associated with a higher risk for MI or acute coronary syndrome (dabigatran, 237 of 20,000 [1.19%] vs. control, 83 of 10,514 [0.79%]; OR=1.33; 95% CI, 1.03-1.71).

Despite its increased risk for MI and acute coronary syndrome, according to the study, dabigatran was associated with a lower mortality than control group (dabigatran, 945 of 19,555 [4.83%] vs. control, 524 of 10,444 [5.02%]; OR=0.89; 95% CI, 0.80-0.99). Given this information, the researchers said although dabigatran might not directly increase MI risk, it may lack the beneficial effects that warfarin and aspirin display in MI prevention.

“The overall benefit and risk balance of dabigatran use appears to be favorable in patients with [atrial fibrillation] because of reduction in ischemic stroke,” the researchers said. “However, the cardiac risk of dabigatran should be investigated further, especially if it is used in populations at high risk of MI or [acute coronary syndrome].”

Disclosure: The researchers report no relevant financial disclosures.

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