Just Missing the Mark: Discharging High-risk Atrial Fibrillation / Flutter without Thromboprophylaxis

Author Affiliation
Linda B. Thompson, MD University of Alabama School of Medicine, Department of Emergency Medicine, Birmingham, Alabama
Michael C. Kurz, MD, MS University of Alabama School of Medicine, Department of Emergency Medicine, Birmingham, Alabama


Atrial fibrillation and flutter (AF) is a pervasive disease affecting 6.1 million people in the United States.1 Each year it is responsible for more than 750,000 hospitalizations and 130,000 deaths.2,3 In contrast to overall declining death rates for cardiovascular disease,4 AF as the “primary or contributing cause of death has been rising for more than two decades.”3 The annual economic burden of AF is six billion dollars; medical costs per AF patient are about $8,707 higher than for non-AF individuals.3

Thrombotic embolism of the cerebral circulation, or stroke, is the principal risk of AF and ranges from less than 2% to greater than 10% annually.5-8 AF is the cause of 100,000–125,000 embolic strokes each year, of which 20% are fatal.9 Anticoagulation to prevent these embolic events is standard of care unless contraindicated.9 However, it is not without risk, as even minor trauma can cause substantial and potentially life-threatening bleeding. Given that AF is the most common arrhythmia among the elderly,1,2,3 balancing these competing risks is challenging.

Anticoagulation for AF is most commonly accomplished with a vitamin K antagonist, warfarin. However, its use requires patient education, medication compliance, dietary consistency, and close monitoring. CHA2DS2-VASc, ATRIA, HAS-BLED, ORBIT, and HEMORR2HAGES are just some of the decision-support tools available to objectively weigh the risk of stroke and life-threatening bleeding from therpy.10-15 Newer, novel oral anticoagulant agents (NOAC) provide a benefit/risk profile that may surpass warfarin, especially when considering initiation in the emergency department (ED). 16-18

In this issue of WestJEM, Smith and colleagues present a prospective observational evaluation of anticoagulation prescribing practices in non-valvular AF. Patients presenting to one of seven Northern California EDs with AF at high risk for stroke were eligible unless admitted, not part of Kaiser Permanente of Northern California (KPNC), or already prescribed anticoagulation. During the 14-month study there were no departmental policies governing the initiation of anticoagulation in AF patients.

The authors report 27.2% of the 312 at high risk for stroke received a new anticoagulant at ED discharge, and only 40% were prescribed oral anticoagulation within 30 days of the index ED visit. Anticoagulation was more likely to be initiated in the ED if the patient was younger (age < 80), had persistent AF at discharge, or when cardiology was consulted during the index visit. Furthermore, only 60.3% of patients were given patient education material on AF in their discharge instructions.19

Critics of Smith et al. will take issue with their inclusion criteria that required participation in KPNC. By definition, all members of KPNC are insured; they also have guaranteed access to timely primary care follow-up and are of higher socioeconomic means than the general population.20 Many of the factors that contribute to successful anticoagulation therapy – diet stability, monitoring of renal function, education and intervention of modifiable risk factors, smoking cessation, and fall risk – can all be assessed by a primary care physician and addressed with shared decision-making ensured in the KPNC system.21

While these limitations are acknowledged by the authors and narrow the generalizability of these findings, Smith and colleagues demonstrate the challenges of addressing ongoing chronic disease in the ED and highlight the complex decision-making required. AF patients without insurance in the U.S. lack reliable access to primary care, and emergency physicians (EPs) likely under-prescribe anticoagulation therapy due to an abundance of caution. EPs are poorly equipped to determine the burden of AF (i.e., is this isolated AF or recurrent and how often is the patient in it) or the origin of the arrhythmia (i.e., is it valvular?). Lacking the objective data to quantify these thromboembolic risk factors of AF, EPs are reluctant to initiate thromboprophylaxis, despite its known benefits, in light of the well-demonstrated risk for life-threatening bleeding.22

However, the risk is largely misperceived. Recent findings from the Spanish EMERG-AF trial demonstrate that initiating this therapy in the ED is at least as safe as in other settings (i.e., in the outpatient clinic or during an inpatient stay) and has clear mortality benefit at one year. Furthermore, that benefit (i.e., stroke prevention) does not come at the expense of reduced effectiveness (i.e., more episodes of major bleeding) over the course of one-year follow-up.23

In addition to highlighting the challenges of prescribing anticoagulation in the ED setting, Smith et al. also illustrate the opportunity for EPs to prevent future strokes in the setting of known AF. This opportunity is likely larger than reported considering the limitations of this investigation (i.e., enrollment predicated upon KPNC participation). Thankfully, there are clear guidelines to assist EPs based upon validated methods of risk-stratification.24,25 Furthermore, of those patients receiving anticoagulation therapy in the first 30 days, more than half were initiated in the ED. While these subjects likely represent the least complex decision-making, these results also suggest some prescribing inertia; anticoagulation was continued by the primary care physician because it has already been initiated in the ED.

Despite these limitations, Smith and colleagues demonstrate an immense target for EPs to improve stroke risk for at least 60% of AF patients discharged from the ED. Coupled with other evidence demonstrating that such practice is efficacious, safe, and cost effective, Smith makes a compelling case that thromboprophylaxis should be initiated in all but the most complex AF patients who will likely be admitted. EDs should develop policies to assure that AF patients can receive anticoagulation therapy on discharge. These local policies could include decision pathways that rely on guidelines, decision-support tools, and account for insurance status. As EPs, we should embrace the responsibility to provide thromboprophylaxis regardless of the likelihood of primary care follow-up. To defer that decision ignores the role emergency medicine plays in providing for the public health in the U.S., and frankly misses the mark.


Section Editor: Mark I. Langdorf, MD, MHPE

Full text available through open access at http://escholarship.org/uc/uciem_westjem

Address for Correspondence: Michael C. Kurz, MD, MS, University of Alabama School of Medicine, Department of Emergency Medicine, OHB 251, 619 19th ST S, Birmingham, AL 35249-7013. Email: mckurz@uabmc.edu. 3 / 2018; 19:361 – 363

Submission history: Revision received December 19, 2017; Submitted February 15, 2018; Accepted February 18, 2018

Conflicts of Interest: By the WestJEM article submission agreement, all authors are required to disclose all affiliations, funding sources and financial or management relationships that could be perceived as potential sources of bias. No author has professional or financial relationships with any companies that are relevant to this study. There are no conflicts of interest or sources of funding to declare.


1. Wolf PA, Abbott Rd, Kannel WB. Atrial fibrillation: a major contributor to strike in the elderly. The Framingham Study. Arch Internal Med. 1987;147(9):1561-4.

2. Go AS, Hylek EM, Phillips KA, et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and risk factors in atrial fibrillation (ATRIA) Study. JAMA. 2001;285(18):2370-5.

3. Atrial Fibrillation Fact Sheet. Available at: https://www.cdc.gov/dhdsp/data_statistics/fact_sheets/fs_atrial_fibrillation.htm. Accessed February 17, 2018.

4. Benjamin EJ, Blaha MJ, Chiuve SE, et al. Heart disease and stroke statistics—2017 update: a report from the American Heart Association. Circulation. 2017;135(10):e146-e603.

5. Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation. Arch Intern Med. 1994;154(13):1449-57.

6. Patients with nonvalvular atrial fibrillation at low risk of stroke during treatment with aspirin: Stroke Prevention in Atrial Fibrillation III Study. JAMA. 1998;279(16):1273-7.

7. Predictors of thromboembolism in atrial fibrillation, I: clinical features of patients at risk. Ann Intern Med. 1992;116(1):1-5.

8. van Latum JC, Koudstaal PJ, Venables GS, et al. Predictors of major vascular events in patients with a transient ischemic attack or minor ischemic stroke and with nonrheumatic atrial fibrillation. Stroke. 1995;26:801-6.

9. Reiffel JA. Atrial fibrillation and stroke: epidemiology. Am J Med. 2014;127(4):e15-6.

10. Olesen JB, Lip GY, Hansen ML, et al. Validation of risk stratification schemes for predicting stroke and thromboembolism in patients with atrial fibrillation: a nationwide cohort study. BMJ. 2011;342:d124.

11. Boriani G, Botto GL, Padeletti L, et al. Improving Stroke Risk Stratification Using the CHADS and CHADS-VASc Risk Scores in Patients with Paroxysmal Atrial Fibrillation by Continuous Arrhythmia Burden Monitoring. Stroke. 2011;42(6):1768-70.

12. Fang MC, Go AS, Chang Y, et al. Comparsion of risk stratification schemes to predict thromboembolism in people with nonvalvular atrial fibrillation. J AM Coll Cardiol. 2008;51(8):810-5.

13. Van den Ham H, Klungel O, Singer DE, Leufkens HGM, Van Staa TP. Comparative performance of ATRIA, CHADS, and CHADS-VASc Risk Scores Predicting Stroke in Patients with Atrial Fibrillation. J Am Coll Cardiol. 2015;66(17):1851-9.

14. Apostolakis S, Lane DA, Guo Y, et al. Performance of the Hemorr(2)Hages, ATRIA, and HAS-BLED bleeding risk-prediction scores in patients with atrial fibrillation undergoing anticoagulation: The AMADEUS (evaluating the use of SR34006 compared to Warfarin or acenocoumarol in patients with atrial fibrillation) study. J Am Coll Cardiol. 2912;60(9):861-7.

15. Senoo K, Proietti M, Lane DA, et al. Evaluation of the HAS-BLED, ATRIA, and ORBIT Bleeding Risk Scores in Patients with Atrial Fibrillation Taking Warfarin. Am J Med. 2016;129(6):600-7.

16. Almutairi AR, Zhou L, Gellad WF, et al. Effectiveness and safety of non-vitamin K antagonist oral Anticoagulants for atrial fibrillation and Venous Thromboembolism: A Systemic Review and Meta-analyses. Clin Ther. 2017;39(7):1456-1478.e36.

17. Friberg L, Oldgren J. Efficacy and safety of non-vitamin K antagonist oral anticoagulants compared with warfarin in patients with atrial fibrillation. Open Heart. 2017;4(2):e000682.

18. Patel P, Pandya J, Goldberg M. NOACs vs warfarin for stroke prevention in NOnvalvular atrial fibrillation. Cureus. 2017;9(6):e1395.

19. Vinson DR, Warton ME, Mark DG, et al. Thromboprophylaxis for Patients with High-risk Atrial Fibrillation and Flutter Discharged from the Emergency Department. West J Emerg Med. 2018;19(2):X-X.

20. Feachem RGA, Sekhri NK, White KL. Getting more for their dollar: a comparison of the NHS with California’s Kaiser PermanenteCommentary: Funding is not the only factor Commentary: Same price, better care Commentary: Competition made them do it. BMJ. 2002:135-143.

21. Panneerselvam S, Baglin C, Lefort W, et al. Analysis of risk factors for over-anticoagulation in patients receiving long-term warfarin. Br J Hematol. 1998;103(2):422-4.

22. Cotton BA, McCarthy JJ, Holcomb JB. Acutely injured patients on dabigatran. N Engl J Med. 2011;365(21):2039-40.

23. Coll-Vinent B, Martín A, Sánchez J, et al. Benefits of Emergency Departments’ Contribution to Stroke Prophylaxis in Atrial Fibrillation. Stroke. 2017;48(5):1344-52.

24. Diener HC, Aisenberg J, Ansell J, et al. Choosing a particular oral anticoagulant and dose for stroke prevention in individual patients with non-valvular atrial fibrillation: part 1. Eur Heart J. ;38(12):852-9.

25. January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014;130(23):e199-267.