Comment Published online: October 16, 2013
Cerebrovasc Dis 2013;36:281–282 DOI: 10.1159/000355981
Using the CHADS2 and CHA2DS2-VASc Scores for Stroke Risk Prediction as well as the Identification of Stroke Outcomes and Cardiac Complications in Patients with and without Atrial Fibrillation Gregory Y.H. Lip University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK
The CHA2DS2-VASc (Congestive heart failure, Hypertension, Age ≥75 years, Diabetes, previous Stroke or transient ischaemic attack, Vascular disease, Age 65–74 years, Sex category) score was first introduced in 2009, following its initial validation in the Euro Heart survey, as a comprehensive risk score to assess the risk of stroke in atrial fibrillation (AF) [1]. This score incorporates the common stroke risk factors seen in AF, and various validation studies on independent cohorts have shown the utility of this score for stroke risk prediction [2, 3]. Also, the CHA2DS2-VASc score works best for identification of ‘truly low-risk’ patients with AF, and following this initial decision step, patients with AF and ≥1 stroke risk factors can be offered effective stroke prevention, that is oral anticoagulant (OAC) therapy, which has the best net clinical benefit [3–5]. This approach is the clinical practice shift advocated in the 2012 focused update of the ESC (European Society of Cardiology) guidelines [6], and is a major sea change from the original approach in older guidelines to focus on the identification of ‘high-risk’ AF patients, for whom we only had – at least until recently – an ‘inconvenient’ drug, warfarin, as the only OAC. The focus on the identification of ‘high-risk’ patients was perhaps justified in the past, since warfarin had many disadvantages and limitations and thus attention to these patients would perhaps be considered ‘best practice’. However, numerous studies have shown that ‘high-risk’ patients are often undertreated [7, 8]. We are also getting better at handling warfarin with efforts to improve the quality of international normalized ratio control, as reflected by the average time within therapeutic range [9], as well as the availability of novel OAC that overcome the many limitations of warfarin [10, 11]. Nonetheless, simple risk scoring systems based on clinical factors alone, including the CHA2DS2-VASc score (and the older CHADS2 – one point each for Congestive heart failure, Hypertension, Age ≥75 years, Diabetes and two points for previous Stroke or transient ischaemic attack – score), generally have relatively modest predictive value for the identification of these ‘high-risk’ patients. The addition of biomarkers to these clinical scores – whether blood based (e.g. natriuretic peptides, troponin, creatinine clearance), urine based (e.g. proteinuria), or based on cardiac imaging (e.g. echocardiography) or cerebral imaging (e.g. small
© 2013 S. Karger AG, Basel 1015–9770/13/0364–0281$38.00/0 E-Mail [email protected] www.karger.com/ced
vessel disease, microbleeds) – would allow for additional precision in identifying ‘high-risk’ patients [12]. Also, the CHA2DS2-VASc and CHADS2 scores assume that each risk factor carries an equivalent weight (or double, in the case of age and stroke), which is a gross simplification but offers relative practicality for everyday easy clinical use. Application of weighted scores based on clinical risk factors, plus adding in additional parameters like deprivation, ethnicity, etc., may offer marginal improvements in defining ‘high-risk’ patients [13], but loses simplicity and practicality for use in the clinic or in the wards with no access to a computer programme. Also, one recently published stroke risk score proposes different weights for clinical risk factors and adds in proteinuria and estimated glomerular filtration rate, and the weighting differs between primary and secondary prevention cohorts [14]. Such an approach still classifies a similarly large proportion of patients as ‘low risk’ using the new score comparable with the older CHADS2 score, and we now know that a CHADS2 score of 0 is not ‘low risk’ given that such patients can still have a stroke and thromboembolism rate as high as 3.2% [3]. The components of the CHA2DS2-VASc score (and, to an extent, the older CHADS2 score) represent common cardiovascular risk factors, so it is no real surprise that such a score can be predictive of stroke and other cardiovascular events, even in non-AF patients [15, 16]. Indeed, the CHADS2 and CHA2DS2-VASc scores have been validated in non-AF cohorts to predict the risk of stroke [16]. Also, the CHADS2 score has prognostic implications in patients with acute coronary syndrome, although performing less well than the more complicated and weighted GRACE (Global Registry of Acute Coronary Events) score [17]. Whilst we now accept the use of the CHA2DS2-VASc score (and the older CHADS2 score) in AF stroke risk stratification, one area that is less well defined is the impact of these scores on stratifying stroke risk outcomes. In the current issue of Cerebrovascular Diseases, Tu et al. [18] perform a unique analysis of the VISTA (Virtual International Stroke Trials Archive). The association between the CHADS2 and CHA2DS2-VASc scores and 3-month stroke outcomes was assessed. They found that both scores were predictive of outcomes, but the pre-stroke CHA2DS2-VASc score was much better than the CHADS2 score in estimating 3-month stroke outcomes in both patients with and without AF, in terms of mortality, functional outcomes (modified Rankin Scale score ≤1) and serious adverse cardiac events. When compared with the CHADS2 score, Tu et al. [18] found that a high-risk pre-stroke CHA2DS2-VASc score had a higher sensitivity for mortality and better negative predictive value for serious adverse cardiac events. Also, a low-risk pre-stroke CHA2DS2VASc score had a higher specificity for good functional outcome. These data would need further confirmation in prospective studies, and the limitations of the retrospective analysis by Tu et al. [18] are well recognized by the authors, given the very nature of the dataset, which focuses on clinical trial patients. Indeed, resid-
Prof. Gregory Y.H. Lip University of Birmingham Centre for Cardiovascular Sciences City Hospital Birmingham B18 7QH (UK) E-Mail g.y.h.lip @ bham.ac.uk
ual confounding is likely from associated comorbidities and concomitant drug therapies, including the investigative medications that are part of the respective trial(s) in VISTA. We are now in a new era where missed opportunities for stroke prevention can be rectified by novel OAC (NOAC), and we could potentially be better at identifying upfront which patients would do well on warfarin, with good-quality international normalized ratio control and high-percentage time within therapeutic range. Indeed, a recently described score [SAMe-TT2R2, i.e. Sex female, Age
Cerebrovasc Dis 2013;36:281–282 DOI: 10.1159/000355981
Using the CHADS2 and CHA2DS2-VASc Scores for Stroke Risk Prediction as well as the Identification of Stroke Outcomes and Cardiac Complications in Patients with and without Atrial Fibrillation Gregory Y.H. Lip University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK
The CHA2DS2-VASc (Congestive heart failure, Hypertension, Age ≥75 years, Diabetes, previous Stroke or transient ischaemic attack, Vascular disease, Age 65–74 years, Sex category) score was first introduced in 2009, following its initial validation in the Euro Heart survey, as a comprehensive risk score to assess the risk of stroke in atrial fibrillation (AF) [1]. This score incorporates the common stroke risk factors seen in AF, and various validation studies on independent cohorts have shown the utility of this score for stroke risk prediction [2, 3]. Also, the CHA2DS2-VASc score works best for identification of ‘truly low-risk’ patients with AF, and following this initial decision step, patients with AF and ≥1 stroke risk factors can be offered effective stroke prevention, that is oral anticoagulant (OAC) therapy, which has the best net clinical benefit [3–5]. This approach is the clinical practice shift advocated in the 2012 focused update of the ESC (European Society of Cardiology) guidelines [6], and is a major sea change from the original approach in older guidelines to focus on the identification of ‘high-risk’ AF patients, for whom we only had – at least until recently – an ‘inconvenient’ drug, warfarin, as the only OAC. The focus on the identification of ‘high-risk’ patients was perhaps justified in the past, since warfarin had many disadvantages and limitations and thus attention to these patients would perhaps be considered ‘best practice’. However, numerous studies have shown that ‘high-risk’ patients are often undertreated [7, 8]. We are also getting better at handling warfarin with efforts to improve the quality of international normalized ratio control, as reflected by the average time within therapeutic range [9], as well as the availability of novel OAC that overcome the many limitations of warfarin [10, 11]. Nonetheless, simple risk scoring systems based on clinical factors alone, including the CHA2DS2-VASc score (and the older CHADS2 – one point each for Congestive heart failure, Hypertension, Age ≥75 years, Diabetes and two points for previous Stroke or transient ischaemic attack – score), generally have relatively modest predictive value for the identification of these ‘high-risk’ patients. The addition of biomarkers to these clinical scores – whether blood based (e.g. natriuretic peptides, troponin, creatinine clearance), urine based (e.g. proteinuria), or based on cardiac imaging (e.g. echocardiography) or cerebral imaging (e.g. small
© 2013 S. Karger AG, Basel 1015–9770/13/0364–0281$38.00/0 E-Mail [email protected] www.karger.com/ced
vessel disease, microbleeds) – would allow for additional precision in identifying ‘high-risk’ patients [12]. Also, the CHA2DS2-VASc and CHADS2 scores assume that each risk factor carries an equivalent weight (or double, in the case of age and stroke), which is a gross simplification but offers relative practicality for everyday easy clinical use. Application of weighted scores based on clinical risk factors, plus adding in additional parameters like deprivation, ethnicity, etc., may offer marginal improvements in defining ‘high-risk’ patients [13], but loses simplicity and practicality for use in the clinic or in the wards with no access to a computer programme. Also, one recently published stroke risk score proposes different weights for clinical risk factors and adds in proteinuria and estimated glomerular filtration rate, and the weighting differs between primary and secondary prevention cohorts [14]. Such an approach still classifies a similarly large proportion of patients as ‘low risk’ using the new score comparable with the older CHADS2 score, and we now know that a CHADS2 score of 0 is not ‘low risk’ given that such patients can still have a stroke and thromboembolism rate as high as 3.2% [3]. The components of the CHA2DS2-VASc score (and, to an extent, the older CHADS2 score) represent common cardiovascular risk factors, so it is no real surprise that such a score can be predictive of stroke and other cardiovascular events, even in non-AF patients [15, 16]. Indeed, the CHADS2 and CHA2DS2-VASc scores have been validated in non-AF cohorts to predict the risk of stroke [16]. Also, the CHADS2 score has prognostic implications in patients with acute coronary syndrome, although performing less well than the more complicated and weighted GRACE (Global Registry of Acute Coronary Events) score [17]. Whilst we now accept the use of the CHA2DS2-VASc score (and the older CHADS2 score) in AF stroke risk stratification, one area that is less well defined is the impact of these scores on stratifying stroke risk outcomes. In the current issue of Cerebrovascular Diseases, Tu et al. [18] perform a unique analysis of the VISTA (Virtual International Stroke Trials Archive). The association between the CHADS2 and CHA2DS2-VASc scores and 3-month stroke outcomes was assessed. They found that both scores were predictive of outcomes, but the pre-stroke CHA2DS2-VASc score was much better than the CHADS2 score in estimating 3-month stroke outcomes in both patients with and without AF, in terms of mortality, functional outcomes (modified Rankin Scale score ≤1) and serious adverse cardiac events. When compared with the CHADS2 score, Tu et al. [18] found that a high-risk pre-stroke CHA2DS2-VASc score had a higher sensitivity for mortality and better negative predictive value for serious adverse cardiac events. Also, a low-risk pre-stroke CHA2DS2VASc score had a higher specificity for good functional outcome. These data would need further confirmation in prospective studies, and the limitations of the retrospective analysis by Tu et al. [18] are well recognized by the authors, given the very nature of the dataset, which focuses on clinical trial patients. Indeed, resid-
Prof. Gregory Y.H. Lip University of Birmingham Centre for Cardiovascular Sciences City Hospital Birmingham B18 7QH (UK) E-Mail g.y.h.lip @ bham.ac.uk
ual confounding is likely from associated comorbidities and concomitant drug therapies, including the investigative medications that are part of the respective trial(s) in VISTA. We are now in a new era where missed opportunities for stroke prevention can be rectified by novel OAC (NOAC), and we could potentially be better at identifying upfront which patients would do well on warfarin, with good-quality international normalized ratio control and high-percentage time within therapeutic range. Indeed, a recently described score [SAMe-TT2R2, i.e. Sex female, Age
