[Thrombotic risk factors and antithrombotic treatment in atrial fibrillation]

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia, and its incidence is rising as the population ages. AF is therefore a growing source of cardiovascular morbidity and mortality due to thromboembolic complications and heart failure. The risk of embolic stroke is multiplied by about 5.6-fold in non rheumatic AF and by 17.6-fold in rheumatic AF Strokes due to AF are often fatal or disabling. Paroxysmal and permanent fibrillation are associated with a similar thromboembolic risk. Embolic complications arise from the left atrium or the left atrial appendage. Known risk factors in patients with AF include a history of thromboembolism or stroke, age > 75 years, heart failure, rheumatic valve disease, mechanical prosthetic valves, arterial hypertension and diabetes mellitus. Ischemic cardiomyopathy, female gender and atherosclerotic vascular disease are associated with an intermediate risk of thromboembolism. Vitamin K antagonist therapy targeting an INR of 2 to 3 reduces the risk of stroke by two-thirds in patients with AF, and causes bleeding in 1.4 % to 3.6 % of patients. The bleeding risk can be evaluated with the CHADS2 scale. Aspirin (75/300 mg per day) reduces the risk of cerebral thromboembolism by about 21%. Current guidelines recommend vitamin K antagonist or dabigatran anticoagulation for patients with a CHADS2 score of 2. Patients with a score of 0 should receive either aspirin or no drug therapy, while patients with a score of 1 may receive either a vitamin K antagonist or aspirin. After successful AF ablation, the existing antithrombotic strategy should be pursued New strategies based on antithrombin or anti-Xa medications will probably have a better risk-benefit ratio.