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Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation
Published on: February 26, 2013
Running after Activated Clotting Time Values in Patients Receiving Direct Oral Anticoagulants: A Potentially
Karim Benali1,2,3, Julien Verain1, Nefissa Hammache1,2
1Département de Cardiologie, CHRU de Nancy, 54500 Vandœuvre lès-Nancy, France.
Insights
Activated Clotting Time (ACT) monitoring during atrial fibrillation (AF) ablation may lead to higher unfractionated heparin (UFH) doses in patients on Direct Oral Anticoagulants (DOACs). This suggests potential UFH overdosing, not increased need, when using the standard ACT target.
Area of Science:
- Cardiology
- Pharmacology
- Medical Devices
Background:
- Activated Clotting Time (ACT) is standard for unfractionated heparin (UFH) dosing in atrial fibrillation (AF) ablation.
- The conventional ACT target of 300s is based on Vitamin K Antagonist (VKA) users.
- Direct Oral Anticoagulants (DOACs) show a weak correlation between ACT and UFH dose.
Purpose of the Study:
- To evaluate the relationship between ACT and actual heparin anticoagulation (anti-Xa activity).
- To compare this relationship across different anticoagulant therapies (DOACs vs. VKA).
Main Methods:
- Prospective inclusion of patients undergoing AF catheter ablation.
- Patients were categorized based on their anticoagulant: rivaroxaban, apixaban, dabigatran, or VKA.
- ACT and anti-Xa activity were measured to assess heparin effect.
Main Results:
- DOAC patients required significantly higher UFH doses and longer times to reach target ACT compared to VKA patients.
- ACT showed a weaker correlation with anti-Xa activity in DOAC users (ρ = 0.19) than VKA users (ρ = 0.53).
- Despite lower ACT values, DOAC patients exhibited higher mean anti-Xa activity than VKA patients.
Conclusions:
- The standard ACT threshold of 300s results in increased UFH administration for DOAC-treated patients during AF ablation.
- This suggests a potential for UFH overdosing in DOAC users, rather than an actual increased requirement.
- Rethinking ACT targets may be necessary for AF ablation patients on DOACs.
Background:
Activated Clotting Time (ACT) guided heparinization is the gold standard for titrating unfractionated heparin (UFH) administration during atrial fibrillation (AF) ablation procedures. The current ACT target (300 s) is based on studies in patients receiving a vitamin K antagonist (VKA). Several studies have shown that in patients receiving Direct Oral Anticoagulants (DOACs), the correlation between ACT values and UFH delivered dose is weak.
Objective:
To assess the relationship between ACT and real heparin anticoagulant effect measured by anti-Xa activity in patients receiving different anticoagulant treatments.
Methods:
Patients referred for AF catheter ablation in our centre were prospectively included depending on their anticoagulant type.
Results:
113 patients were included, receiving rivaroxaban (n = 30), apixaban (n = 30), dabigatran (n = 30), and VKA (n = 23). To meet target ACT, a higher UFH dose was required in DOAC than VKA patients (14,077.8 IU vs. 9565.2 IU, p < 0.001), leading to a longer time to achieve target ACT (46.5 min vs. 27.3 min, p = 0.001). The correlation of ACT and anti-Xa activity was tighter in the VKA group (Spearman correlation ρ = 0.53), compared to the DOAC group (ρ = 0.19). Despite lower ACT values in the DOAC group, this group demonstrated a higher mean anti-Xa activity compared to the VKA group (1.56 ± 0.39 vs. 1.14 ± 0.36; p = 0.002).
Conclusion:
Use of a conventional ACT threshold at 300 s during AF ablation procedures leads to a significant increase in UFH administration in patients treated with DOACs. This increase corresponds more likely to an overdosing than a real increase in UFH requirement.
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