Effect of pre-procedural interrupted apixaban on heparin anticoagulation during catheter ablation for atrial fibrillation: a prospective observational study

Effective intraprocedural anticoagulation is considered essential to minimize the risk of thromboembolism in catheter ablation (CA) of atrial fibrillation (AF). The effect of interrupted apixaban on intraprocedural heparin dosing requirements and levels of achieved anticoagulation with heparin has not been well studied. The purpose of the present study was to compare heparin administration and activated clotted times (ACTs) for patients undergoing CA for AF treated with interrupted apixaban before the procedure with patients on uninterrupted warfarin. Consecutive patients undergoing CA for AF treated with interrupted apixaban or uninterrupted warfarin were prospectively enrolled. Heparin administration determined by a standard protocol and normalized to patient weight and procedure duration, as well as rapidity, and degree of anticoagulation with heparin (as measured by mean ACT, peak ACT, time to ACT a parts per thousand yen300 s, and time to ACT a parts per thousand yen350 s) were compared between the groups. Forty-eight patients were enrolled (25 apixaban and 23 warfarin). Heparin administered by bolus (51.3 +/- 21.5 vs 27.8 +/- 9.6 units/kg/h; p < 0.001) and mean heparin drip rate (25.3 +/- 3.6 vs 20.7 +/- 2.4 units/kg/h; p < 0.001) were significantly higher in the apixaban group compared to the warfarin group. Despite greater heparin administration, apixaban patients achieved a significantly lower mean ACT (332.3 +/- 17.0 vs 384.5 +/- 53.9; p < 0.001) and peak ACT (369.5 +/- 22.6 vs 432.3 +/- 75.8, p < 0.001) compared to the warfarin group. The time to ACT a parts per thousand yen350 s (66.7 +/- 35.8 vs 26.9 +/- 34.0; p < 0.001) was significantly longer for apixaban-treated patients. Outcome differences persisted after analysis using linear models and Cox proportional hazard regression with adjustment for propensity scores. A standard intraprocedural heparin protocol results in delayed and lower levels of anticoagulation as measured by the ACT for interrupted apixaban-treated patients in comparison to those on uninterrupted warfarin during CA of AF.