136-05: Response to heparin loading dose in patients undergoing pulmonary vein isolation due to atrial fibrillation. Effect of pre-procedure oral anticoagulation strategy

Abstract

The aim of the study was to evaluate the response to initial bolus of heparin during the catheter ablation of atrial fibrillation in patients on interrupted novel oral anticoagulants (NOACs) and uninterrupted vitamin K antagonists (VKA). Methods: Consecutive 64 patients (67,2% males; median age 59; 20 treated with NOACs, 26 with VKA and 18 without any anticoagulation treatment) qualified to the pulmonary vein isolation (PVI) procedure from February 2014 to August 2015 were analyzed retrospectively. Treatment with VKA was continued without any interruption to maintain the international normalized ratio (INR) between 2 and 3 during the ablation procedure. NOACs (dabigatran or rivaroxaban) had been withdrawn 48 hours prior to the procedure and restarted 6 hours after PVI (dabigatran) or in the morning first day following the ablation. The initial bolus of heparin was administered immediately after the transseptal puncture, in a dose between 90 and 110 u/kg. The first measurement of ACT was done 15 minutes after the first injection of heparin. Target ACT was 300 seconds. Results: The ACTs after the initial bolus in the groups without any anticoagulation (NA), treated with VKA and NOACs were 234 s (220-246; NA vs. VKA p , 0,0001; NA vs NOAC p = 0.7365), 307 s (255-360) and 238 s (219-267; VKA vs. NOAC p , 0.0001), respectively. In the analyzed group of patients only 16 reached the level of ACT .300 s after the initial bolus of heparin, while 48 did not achieve the therapeutic anticoagulation. The level of ACT. 300 s was reached in 11,1% of patients without anticoagulation treatment, 53,9% of patients on VKA and 0% on NOACs (without anticoagulation vs. VKA p , 0.0138; without anticoagulation vs. NOAC p = 0.6528, VKAvs. NOAC p , 0.0001). Conclusions: Patients on NOACs had significantly lower level of activated clotting time after the initial bolus of heparin in comparison to the group on uninterrupted warfarin. There were no statistically significant differences between the NOACs group and patients without any previous anticoagulation therapy.