Purpose: Measuring the anticoagulant effect of heparin during radiofrequency ablation (RFA) in patients taking apixaban and rivaroxaban is challenging, since the activated coagulation time (ACT) does not seem to reflect the true anticoagulant activity of these drugs. We therefore evaluated coagulation properties of apixaban and rivaroxaban during RFA by different coagulation assays to better monitor periprocedural hemostasis.
Methods: The study included 90 patients (61 ± 12 years) with atrial fibrillation who underwent RFA procedures. Patients received 20 mg rivaroxaban (n = 73) once or 5 mg apixaban (n = 17) twice daily 4 weeks prior to the procedure. During RFA, unfractionated heparin i.v. was given to maintain an ACT of 250-300 s. Blood samples were taken before and 10, 60, and 360 min after heparin administration.
Results: Heparin displayed a lower anti-Xa activity in rivaroxaban-treated patients compared to apixaban-treated patients. In contrast, D-dimer and prothrombin fragment F1+2 plasma levels indicated a higher activation of the coagulation cascade in apixaban/heparin than in rivaroxaban/heparin patients. This discordant coagulative state measured in vitro had no clinical impact in terms of bleeding or thromboembolic complications.
Conclusion: We found different biochemical responses to rivaroxaban/heparin and apixaban/heparin during RFA. Precaution is necessary when monitoring periprocedural hemostasis in DOAC patients to avoid mismanagement.
Keywords: Atrial fibrillation; DOACs; FXa activity; Heparin; Radiofrequency ablation.