Reasons to Select Warfarin
Warfarin may be a more appropriate option in patients with a high bleeding risk due to the current lack of a reversal agent for dabigatran. Dabigatran is not recommended in patients with creatinine clearances < 30 mL/min; thus, warfarin may be a better choice in patients with impaired renal function. It may be reasonable to consider switching a current warfarin patient with a history of variable INRs to a TSOAC in preparation for cardioversion to potentially shorten the time to cardioversion if the patient is highly symptomatic. Low molecular weight heparin may be considered as a last resort for patients who may not be able to tolerate warfarin or TSOACs. However, if LMWH were to be used, it may be more reasonable to consider a TEE-guided DCCV rather than 3 full weeks of anticoagulation with LMWH.
Limitations
There were several limitations to this single site, retrospective, QI project with a small sample size. All patients were older, adult males. Results may not be relevant to other institutions and patient populations, including females and younger patients.
Standardized anticoagulation clinic encounter times (15 minutes for phone call and 5 minutes for letter) were used to calculate pharmacist’s monitoring time costs for warfarin patients. This standardized time did not account for the amount of time spent in monitoring and creating dosing plans that may vary drastically between patients. The time and cost analyses did not account for pharmacy technician reminder phone calls for missed or late INR draws or home health nurse INR draws and visits. Theoretically, patients with home health services have fewer missed or late INRs, and phone encounter times may be shorter between the pharmacist and the nurse vs the pharmacist and the patient.
Finally, it was difficult to capture administrative reasons for delayed DCCV in both groups. In the warfarin group, communication between the anticoagulation clinic and the cardiology team may have been delayed due to staff vacations, sick time, or differences in staff work schedules. In both groups, assessing how procedure scheduling affected wait times was difficult. Procedure room availability, clinic schedules, staff schedules, and preprocedure appointment availability likely impacted patient wait times for DCCV but were difficult to assess and quantify. Finally, power was not calculated for this project.
Conclusions
Based on the recommendations of the CHEST 2012 guidelines, the ACC/AHA/HRS 2014 guidelines, and recent literature, TSOACs are reasonable anticoagulants to consider before and after planned cardioversion of atrial arrhythmias. The findings of this QI project support the
use of either dabigatran or warfarin before a planned cardioversion at VAPORHCS. Several factors should be considered when choosing an oral anticoagulant before a planned DCCV, including indication, duration of anticoagulation, previous anticoagulant use, medication adherence, renal function, risk of thromboembolism vs bleeding risk, and potential need for a reversal agent.
Author disclosures
The authors report no actual or potential conflicts of interest with regard to this article.
Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.