Activated clotting time on the day of atrial fibrillation ablation for minimally interrupted and uninterrupted direct oral anticoagulation therapy: Sequential changes, differences among direct oral anticoagulants, and ablation safety outcomes.

Background: Activated clotting time (ACT)-guided heparinization is used during atrial fibrillation (AF) ablation. Differences in sensitivity to ACT assays have been identified among different direct oral anticoagulants (DOACs).

Objective: We aimed to examine ACT just before ablation (pre-ACT) for different ablation start times (9:00, 11:00, 13:00, or 15:00) and ablation safety outcomes in minimally interrupted (min-Int) and uninterrupted (Unint) DOAC regimens and examine differences in pre-ACT values among four DOACs.

Methods: Consecutive patients were randomized into the min-Int (n = 307) or Unint (n = 277) groups. DOACs examined were apixaban, dabigatran, edoxaban, and rivaroxaban.

Results: No sequential changes in pre-ACT values were observed for each DOAC used and for all four DOACs combined in the min-Int and Unint groups. There was no meaningful difference in pre-ACT at each ablation start time between the groups. Clinically significant differences in overall pre-ACT were not obtained between the groups (138 ± 24 vs 142 ± 23 seconds). The pre-ACT (baseline) value for dabigatran was on average 29 seconds higher than that for the other three DOACs. The min-Int and Unint groups showed similar thromboembolic (0% vs 0%) and bleeding event rates (major, 1% vs 0%; all, 3.5% vs 2.5%).

Conclusion: The pre-ACT did not show a sequential change in the min-Int and Unint groups. No notable differences in the time-dependent change in pre-ACT between the groups were observed. Variations in baseline ACT suggest the need for moderate adjustment of ACT for adequate modification of heparin dose for the other three DOACs. Both regimens provided similar acceptable AF ablation safety outcomes.