Aims: Thrombocytopenia was one of the exclusion criteria in randomized trials in which non-vitamin K antagonist oral anticoagulants (NOACs) were tested. The safety of NOACs in patients with atrial fibrillation (AF) and thrombocytopenia remains unclear.
Methods: We studied 62 patients with AF aged from 53 to 85 (mean 70.5) years with platelet count from 50 to 100 × 109/L who were treated with rivaroxaban 15 mg once daily (33.9%), dabigatran 110 mg twice daily (bid) (54.8%), or apixaban 2.5 mg bid (11.3%). Age- and sex-matched AF patients with normal platelet count and similar CHA2DS2-VASc scores who were treated with the recommended doses of NOACs served as a reference group.
Results: Patients were followed for a mean of 55 months (range, 23-64 months). In the thrombocytopenia group bleeding risk was higher (mean HAS-BLED score 2.0, vs. 1.0, P < 0.0001). During follow-up in thrombocytopenic and normocytopenic patients, we observed similar rates of major bleeding (1.8%/year vs. 2.7%/year, P = 0.49), clinically relevant nonmajor bleeding (CRNMB) (1.5%/year vs. 1.1%/year, P = 0.74), ischemic stroke and transient ischemic attacks (1.8%/year vs. 1.5%/year, P = 0.8), and death (1.06%/year vs. 1.11%/year, P = 0.96). The risk of bleeding and stroke was unaffected by the type of the NOAC used in both groups. Major bleedings and clinically relevant nonmajor bleeding in thrombocytopenic patients on NOACs were predicted only by age (hazard ratio 1.1, 95% confidence interval 1.0-1.3, P = 0.04).
Conclusions: Our findings indicate that in AF patients with mild thrombocytopenia, anticoagulation with NOAC at reduced doses seems to be safe and effective.