Major risks of dual and triple antithrombotic therapy in patients with newly diagnosed atrial fibrillation

Patients with atrial fibrillation are at an increased risk of ischemic stroke. In this high-risk population, vitamin K antagonists such as warfarin have been shown to be highly effective in preventing this event. However, the afflicted often receive multiple antithrombotic drugs such as warfarin in combination with aspirin and clopidogrel to manage their associated cardiovascular conditions. Yet, each of these drugs is known to increase the bleeding risk, and especially intracranial hemorrhage. Moreover, intracranial hemorrhage associated with the use of warfarin is often fatal.

Nonetheless, very few population-based studies have explicitly quantified the risk associated with combined treatment to date.

Thus the primary purpose of this current research was to find out more about the association between the concurrent use of different antithrombotic drugs and the bleeding risk in patients newly diagnosed with atrial fibrillation, who seem to be at an even higher risk of bleeding than patients with chronic disease. Suissa and his team conducted a population-based cohort study, relying on the General Practice Research Database (GPRD), a primary care database from the United Kingdom, to identify patients newly diagnosed with atrial fibrillation between 1993 and 2008. Within this cohort including more than 70,000 adults (mean age: 74.1 years), 10,850 patients experienced a bleeding event during follow-up (604 of which were intracranial hemorrhages).

The risk of bleeding episodes with dual and triple antithrombotic therapy was found to be additive, and chances of bleeding events increased in particular with combinations containing warfarin. Triple therapy was associated with the highest risk: For the combined use of both aspirin and clopidogrel with warfarin, the bleeding risk was increased almost 4-fold compared with non-use. When compared with warfarin single therapy, triple therapy was associated with an 80% increased risk.

These results are clinically significant and might help to refine management of patients with atrial fibrillation who often have further conditions indicated for these drugs. In view of these findings, patients currently treated with multiple antithrombotic therapies in combination should discuss with their physician the risk-benefit profile of such combination treatment with respect to the potential additive bleeding risks.

More information: Azoulay L , Dell'Aniello S, Simon T, Renoux C , Suissa S. The concurrent use of antithrombotic therapies and the risk of bleeding in patients with atrial fibrillation. Thromb Haemost 2013; 109: 431-439. nl5.sitepackage.de… cc651ad99131

Journal reference: Thrombosis and Haemostasis

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