Modern Management of Atrial Fibrillation Requires Initial Identification of “Low-Risk” Patients Using the CHA₂DS₂-VASc Score, and Not Focusing on “High-Risk” Prediction

Abstract

Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp statistics approximately 0.6-0.7), but this depends on the study setting and design. In one of the largest validation cohorts, 5 CHA2DS2-VASc had a c-statistic of 0.850, which outperformed the CHADS2 score (c-statistic 0.722) in predicting "high-risk" patients who developed thromboembolism; importantly, CHA2DS2-VASc was also better than CHADS2 in defining those patients at low-risk of thromboembolism. The other risk score referred to by Ikeda, the R2CHADS2 score, has many limitations that have been well recognised, notwithstanding its initial derivation from a selected trial anticoagulated cohort that did not include the range of stroke risk and excluded those with severe renal impairment. 6 Also, other "real world" studies have shown that adding extra points for "renal impairment" (as with the R2CHADS2 score) did not improve the predictive value of CHA2DS2-VASc. 7-9Nonetheless, various attempts to improve prediction of "highrisk" AF subjects using biomarkers have been proposed, but the (very) marginal improvements in c-statistics over clinical-based scores were at the cost of substantially much lower simplicity and applicability for everyday clinical practice.If Ikeda assumes that "a simple score is better," then classifying patients as "low-risk" using the CHADS2 score is simply putting many AF patients at risk of fatal and devastating strokes. In the Danish nationwide cohort study, based on >17,300 patients with a CHADS2 score=0, stroke rates were as high as 3.2% (with the upper boundary of the 95% CI as high as 6.4%) per year. 10 Would anyone reasonably withhold anticoagulation therapy for a 74-year-old female patient with AF and prior peripheral artery disease? Such a hypothetical patient would have a CHADS2 score=0 ("low risk"), but a CHA2DS2-VASc score=3 (for which anticoagulation is recommended). A comparison of CHA2DS2-VASc, CHADS2 and the van Walraven scores found that only the CHA2DS2-VASc score was a significant predictor of the absence of thromboembolism for a cohort of lone AF patients followed up over 12 years. 11If CHA2DS2-VASc is "very complicated", then Ikeda should be reassured that a recent survey of European clinical practice demonstrated uptake and use of this score in 97.7% of respondents whereas the HAS-BLED score was used by >78% for the assessment of bleeding-risk. 12 The EORP-AF survey found that anticoagulation rates were approx 80%, especially for lthough atrial fibrillation (AF) increases the risk of stroke, this risk is not homogeneous and depends on associated stroke risk factors, which have resulted in clinical scores to aid stroke risk stratification of AF patients. When vitamin K antagonists (VKAs) were the only option for oral anticoagulation, the focus was on the identification of "high risk" patients to be targeted for (inconvenient) VKA treatment. However, the landscape of thromboprophylaxis has changed markedly with the improvements in our understanding of how to use the VKAs ...

Validation of a Modified CHA 2 DS 2 -VASc Score for Stroke Risk Stratification in Asian Patients With Atrial Fibrillation

“…Rather than a categorized approach to stroke risk stratification focusing on high-risk patients, a simple approach to thromboprophylaxis is to initially identify truly low-risk patients in whom OACs could be clearly omitted. 25 The ability of a scoring scheme to identify AF patients who are truly low risk of ischemic stroke is an even more important issue in Asians because this risk among Asians may be much higher than that among Caucasians, as demonstrated in registry studies and randomized trials. 10,[26][27][28][29][30] Indeed, the CHA 2 DS 2 -VASc score has been shown to consistently better than the older CHADS 2 score in identifying low-risk patients, even among Asian patients.…”

Comparisons of CHADS2 and CHA2DS2-VASc scores for stroke risk stratification in atrial fibrillation: Which scoring system should be used for Asians?

“…Current international guidelines focus on how to identify "truly low-risk" patients, in whom OACs were not recommended. 20 In the era of non-vitamin K antagonist oral anticoagulants (NOACs), the accuracy of a scoring system in identifying low-risk patients is an even more important issue since the great improvements on convenience and safety of NOACs may lower the threshold for initiating OAC for AF patients.…”

New Biomarkers and Risk Stratification in Atrial Fibrillation

“…The next step (STEP 2) would be to offer effective stroke prevention (which is OAC, whether as one of the non-VKA oral anticoagulants [NOACs], or well-managed VKA with a time in therapeutic range >70%) 18 to patients with ≥1 additional stroke risk factors. Thus, the management decision (to use OAC or not) is already made after that initial first step to pick out the low-risk patients; making subsequent refinement of stroke risk in those with CHA 2 DS 2 -VASc score ≥2 (with biomarkers, single or multiple, old or new) matters much less 19 ( Figure). In summary, biomarkers in AF offer additional insights into pathophysiology and may be potential surrogates for complications or risk.…”