title: Determinants of Heparin Dosing and Complications in Patients Undergoing Left Atrial Ablation on Uninterrupted Rivaroxaban.
abstract: BACKGROUND
  Patients on rivaroxaban have variable international normalized ratios (INRs) but it is uncertain if INR impacts procedural heparin requirement during left atrial ablation. We sought to examine the determinants of heparin dosing in this patient population.
  
  
  METHODS
  We reviewed consecutive patients who received rivaroxaban within 24 hours of left atrial ablation and compared them to patients on uninterrupted warfarin. The determinants of heparin requirement were evaluated using regression analysis. We then tested a weight-based heparin dose prospectively in rivaroxaban patients.
  
  
  RESULTS
  There were 258 patients on rivaroxaban and 213 on warfarin. The mean INR was 1.4 in the rivaroxaban group and 2.3 in the warfarin group (P < 0.01). To achieve an activated clotting time (ACT) >350 seconds, rivaroxaban patients required significantly more heparin (166.9 vs. 78.3 units/kg, P < 0.001). In the rivaroxaban group, body weight was the strongest predictor of heparin dose (r = 0.52), while INR was weakly correlated (r = -0.21). In the prospective group, 25 patients were given an initial heparin dose of 120 units/kg with 22/25 (88%) achieving an ACT > 300 seconds. There were seven and three cases of pericardial effusion in rivaroxaban and warfarin patients, respectively (P = 0.41). The average volume drained in the rivaroxaban group was elevated (988.6 vs. 275.0 mL, P = 0.21).
  
  
  CONCLUSIONS
  Body weight is the strongest predictor of procedural heparin requirement during left atrial ablation in patients on uninterrupted rivaroxaban, even in those with an elevated INR. A heparin dose of 120 units/kg achieves an ACT > 300 seconds in the majority of patients. In cases of pericardial effusion, bleeding may be prolonged.
authors.affiliation: Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Alan D
authors.initials: AD
authors.lastname: Enriquez
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Timothy
authors.initials: T
authors.lastname: Churchill
authors.affiliation: Division of Cardiovascular Medicine, University of Missouri School of Medicine, Columbia, Missouri.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Gautam
authors.affiliation: Southside Hospital, North Shore Long Island Jewish, Bayshore, New York.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Chinitz
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Chirag R
authors.initials: CR
authors.lastname: Barbhaiya
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Roy M
authors.initials: RM
authors.lastname: John
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Usha B
authors.initials: UB
authors.lastname: Tedrow
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Koplan
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: William G
authors.initials: WG
authors.lastname: Stevenson
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Michaud
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000008:administration & dosage; D001281:Atrial Fibrillation / Q000453:epidemiology* / Q000601:surgery*; D001835:Body Weight; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination / Q000706:statistics & numerical data; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage / Q000009:adverse effects; D006325:Heart Atria / Q000187:drug effects / Q000601:surgery; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control; D011292:Premedication / Q000706:statistics & numerical data; D015995:Prevalence; D012307:Risk Factors; D000069552:Rivaroxaban / Q000008:administration & dosage* / Q000009:adverse effects; D013923:Thromboembolism / Q000453:epidemiology* / Q000517:prevention & control*; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
chemical_list: D000925:Anticoagulants; D005343:Fibrinolytic Agents; D006493:Heparin; D000069552:Rivaroxaban
keywords: ablation; atrial fibrillation; heparin; pericardial effusion; rivaroxaban