Key result
Although the activated clotting time is poorly sensitive to direct factor Xa inhibitors, the higher unfractionated heparin doses required in patients on uninterrupted DOACs do not dangerously compromise hemostatic competence during catheter ablation.
Why the study?
Patients on DOACs undergoing CAAF require higher UFH doses to achieve the ACT target of 300 s, raising concerns about potential heparin overdosing due to poor ACT sensitivity to DOACs.
Does an uninterrupted DOAC approach increase bleeding or thrombotic risk compared to uninterrupted VKAs in patients undergoing catheter ablation of atrial fibrillation?
Does an uninterrupted DOAC approach increase bleeding or thrombotic risk compared to uninterrupted VKAs in patients undergoing catheter ablation of atrial fibrillation?
The low sensitivity of ACT to residual DOAC effects should not deter its use to guide UFH dosing during CAAF, as the higher UFH doses required do not increase bleeding risk and are necessary to prevent catheter-induced thrombosis.
ACT-guided UFH dosing remains appropriate in uninterrupted DOAC patients; leaves open randomized confirmation versus VKA strategies.
Most patients present for catheter ablation of atrial fibrillation (CAAF) with residual or full effect of vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs). In daily practice, it has been observed that the activated clotting time (ACT) was actually poorly sensitive to the effect of DOACs and that patients on DOACs required more unfractionated heparin (UFH) to achieve the ACT target of 300 s during the procedure, leading some authors to worry about potential overdosing. Conversely, we hypothesize that these higher doses of UFH are necessary to achieve adequate hemostasis during CAAF regardless of the residual effect of DOACs. During CAAF, thrombosis is promoted mainly by the presence of thrombogenic sheaths and catheters in the bloodstream. Preclinical data suggest that only high doses of DOACs are able to mitigate catheter-induced thrombin generation, whereas low dose UFH already do so. In addition, the effect of UFH seems to be lower in patients on DOACs, compared to patients on VKAs, explaining part of the differences observed in heparin requirements. Clinical studies could not identify increased bleeding risk in patients on DOACs compared to those on VKAs despite similar efficacy during CAAF procedures. Moreover, targeting a lower ACT was associated with an increased periprocedural thrombotic risk for both DOAC and VKA patients. Therefore, the low sensitivity of the ACT to the residual effect of DOACs should not be a major concern in its use in the interventional cardiology laboratory.
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Hardy et al. (2022) conducted a review in Atrial Fibrillation. Uninterrupted DOACs vs. Uninterrupted VKAs was evaluated. Although the activated clotting time is poorly sensitive to direct factor Xa inhibitors, the higher unfractionated heparin doses required in patients on uninterrupted DOACs do not dangerously compromise hemostatic competence during catheter ablation.
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