Anticoagulation in atrial fibrillation

The clinical review on Anticoagulation in atrial fibrillation by Benjamin A Steinberg and Jonathan P Piccini was excellent covering various aspects of risk stratification, therapeutic agents with appropriate evidences and management of complications.

Assigning atrial fibrillation (AF) patients to appropriate risk band is the key step which determines further management of the condition. Although both CHADS2 and CHA2Ds2-VASc scoring systems are in use for stratification, recently unveiled AHA/ACC/HRS AF guideline 2014 explicitly recommends, CHA2Ds2-VASc as a tool for risk stratification in patients with non-valvular AF.1
CHA2Ds2-VASc, even though increasingly gaining acceptance as tool for risk stratification has its limitations as highlighted by authors of the current review. This tool has been validated in certain narrow cohorts of patients and there are suggestions to validate this tool in some specific populations. Hobbs et al suggested to validate this tool in the elderly with suitable modification as this tool has limited ability to predict risk of stroke in this group.2 In a study reported from Chinese population, it has been reported that both CHADS2 and CHA2Ds2-VASc scores have limitations in predicting 1-year prognosis of stroke recurrence in patients with non valvular AF. The predictive values of these tools were improved by adding NIHSS scores.3 These observations suggest that there is a need to validate CHA2Ds2-VASc across various groups to generalize it as a tool for risk stratification in AF patients.
In our setting, when we studied the prescriptions of AF patients we understood that there is reluctance among clinicians to prescribe oral anti-coagulants even for eligible patients, as they fear potential bleeding events. This issue has been highlighted by Campbell et al in their response to Jonas et al’s work on risk stratification schemes for strokes and thromboembolism.4 These observations underscores the need for greater efforts to reach out to clinicians on the available evidences and tools and their application in clinical decision making.

References

1. January CT, Wann LS, Alpert JS, Field ME, Calkins H, Murray KT, Cleveland Jr JC, Sacco RL, Cigarroa JE, Stevenson WG, Conti JB, Tchou PJ, Ellinor PT, Tracy CM, Ezekowitz MD, Yancy CW, 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: Executive Summary, Journal of the American College of Cardiology (2014), doi: 10.1016/j.jacc.2014.03.021.
2. Hobbs FD, Roalfe AK, Lip GY, Fletcher K, Fitzmurice DA, Mant J. Atrial Fibrillation in the Aged Investigators and Midland Research practices Consortium Network. Performance of stroke risk scors in older people with atrial fibrillation not taking warfarin: Comparative cohort study from BAFTA trial. British Medical Journal. 2011; 342:d3653.
3. Li SY, Zhao XQ, Wang CX, Liu LP, Liu GF, Wang YL, Wang YJ. One Year Clinical Prediction in Chinese ischemic stroke patients using the CHADS2 and CHA2DS2-VASc scores: the China National Stroke Registry. CNS Neurosciences and Therapeutics. 2012;18(12):988-93.
4. Jonas BO, Gregory HL, Morten LH, Peter RH, Janne ST, Jesper L et al. Validation of risk stratification schemes for predicting stroke and thromboembolism in patients with atrial fibrillation:nationwide cohort study. British Medical Journal.2011; 342: d124. doi: 10.1136/ bmj.d124