Higher initial weight-based heparin dosing is required with direct oral anticoagulants during catheter ablation for atrial fibrillation

Background: Heparin dosing of patients anticoagulated with direct oral anticoagulants (DOACs) undergoing atrial fibrillation (AF) ablation can be challenging as they require more heparin than those on warfarin therapy. We sought to compare periprocedural activated clotting times (ACTs) of patients on warfarin vs. DOAC and determine an optimal weight-based heparin dosage strategy. Methods: Patients who underwent AF ablation over 28 months were reviewed for type of anticoagulation, intraprocedural heparin dosing, ACTs, and adverse outcomes. A heparin dosing strategy was then tested in a prospective validation cohort. Results: There were 89 patients in the DOAC group and 43 in the warfarin group. Demographics, comorbidities, and complication rates were similar. Mean ACT and percentage of therapeutic ACTs were lower in the DOAC group, most significantly in those with a weight > 90 kg. In DOAC patients, a higher initial heparin bolus ≥ 150 units/kg yielded a higher percentage of therapeutic intraprocedural ACTs (49% ± 10 vs. 29% ± 7, p = 0.0008). In a prospective validation cohort of 25 patients administered an initial heparin bolus ≥ 150 units/kg, the mean ACT was 295 ± 33 and 49% of the ACTs collected were therapeutic, similar to findings of our high-dose retrospective subgroup. Conclusion: Patients on DOACs require more heparin during AF ablation to achieve therapeutic ACT. We suggest an initial heparin dose of at least 150 units/kg in this subset of patients, particularly in those with a weight > 90 kg.