Remaining activity of temporary interrupted direct oral anticoagulants and its impact on intra‐ablation heparinization in patients with atrial fibrillation: Comparisons across four drugs and two dose regimens

Background Atrial fibrillation (AF) ablation with minimally interrupted direct oral anticoagulants (DOACs) may raise a concern about their remaining activity. We tested the residual activity of four different DOACs and its impact on intraprocedural heparinization in patients undergoing AF ablation. Methods We measured the anti‐factor Χa activity for rivaroxaban, apixaban, and edoxaban, and serum DOAC concentration for rivaroxaban, apixaban, and dabigatran, 24 hours after the last intake in patients undergoing AF ablation treated with standard or reduced doses of DOACs. The heparin requirement during the procedure was also measured. Results We enrolled 34 patients with rivaroxaban, 35 with apixaban, 32 with edoxaban, and 31 with dabigatran, and among them, 30 were treated with reduced doses. The anti‐factor Χa activity was the highest in the apixaban group among the patients with standard doses. The DOAC concentration was paradoxically lower in patients with standard doses than in those with reduced doses among the patients with rivaroxaban (34.3 ± 19.8 vs 56.6 ± 7.7 ng/mL; P = .01) and dabigatran (12.6 ± 10.6 vs 23.4 ± 14.7 ng/mL; P = .03). The total heparin requirement per body surface area had significant correlations with the anti‐factor Χa activity (r = −.36) and DOAC concentration (r = −.32). Two different multiple linear regression models (adjusted R2 = 0.56 and 0.6, respectively) revealed that the anti‐factor Χa activity (β = −.28; P = .002) and DOAC concentration (β = −.38; P < .001) were independent determinants of the total heparin requirement. Conclusions Factors determining residual DOAC activity may include its type and dose regimen, and it may influence the heparin requirement during AF ablation.