P2-CHA2DS2-VASc Score

P₂-CHA₂DS₂-VASc Score

P₂-CHA₂DS₂-VASc score adds additional two points to the CHA₂DS₂-VASc score for an abnormal P wave axis to predict risk of stroke in atrial fibrillation (AF) [1]. The seminal study was an attempt to identify utility of P wave indices in sinus rhythm to predict the risk of stroke over and above the existing CHA₂DS₂-VASc score. P wave indices evaluated were prolonged P wave duration, abnormal P wave axis, advanced interatrial block and abnormal P wave terminal force in lead V1. They found that abnormal P wave axis which is an ECG correlate of left atrial abnormality improves the prediction of ischemic stroke. They concluded that P₂-CHA₂DS₂-VASc score is a better prediction tool for AF related ischemic stroke than CHA₂DS₂-VASc score.

Scoring in P₂-CHA₂DS₂-VASc gives 2 points for abnormal P wave axis, 1 point for age between 65 to 74 years and 2 points for age 75 or more, 1 point each for female sex, heart failure, hypertension, diabetes mellitus and previous myocardial infarction/peripheral artery disease, and 2 points for prevalent stroke or transient ischemic attack. The study used data from two large community based prospective cohort studies for prediction of atrial fibrillation related stroke. The hypothesis was tested in the ARIC (Atherosclerosis Risk in Communities) data [2] and validated in the MESA (Multi-Ethnic Study of Atherosclerosis) data [3].

In the study used for deriving P₂-CHA₂DS₂-VASc score, advanced interatrial block was also independently associated with AF related stroke. But it did not improve risk prediction in their models, which they thought could be due to low prevalence in their population [1]. Fibrotic atrial remodeling and enlargement have been considered as important components of proarrhythmic and prothrombotic substrate in the development of AF and AF related stroke [4]. P wave indices are surrogates for detection of this substrate on the ECG [5].

P₂-CHA₂DS₂-VASc score was developed as several analyses of large databases have noted the limitations of CHA₂DS₂-VASc score [1]. It was thought that limitations of CHA₂DS₂-VASc score may be because it measures only atherosclerotic risk factors and does not directly reflect mechanisms of AF related thromboembolism. P₂-CHA₂DS₂-VASc score was better at correctly identifying the stroke risk in low risk individuals. Authors also noted that P wave axis is automatically reported in most commercially available ECG machines so that it is easy to incorporate it into a risk score.

CHADS₂ and CHA₂DS₂-VASc have been used to predict risk of stroke or TIA (transient ischemic attack) in patients discharged after acute coronary syndrome without known AF [6]. Accuracy was similar to that observed in historical populations with non valvar AF and lower absolute event rates.

Stroke prediction by the CHA₂DS₂-VASc score in people without AF but with abnormal P wave indices was comparable to people with AF [1]. In other words, P₂-CHA₂DS₂-VASc score might be useful to predict stroke in persons without AF, but needs validation in further studies. P₂-CHA₂DS₂-VASc score cannot be used in patients with persistent or permanent AF who have no ECGs in sinus rhythm, because P wave axis cannot be calculated in the presence of AF.

Though P₂-CHA₂DS₂-VASc score was reviewed in the National Institute for Health and Care Excellence (NICE, UK) draft for consultation regarding tools to predict stroke in atrial fibrillation, it has not been incorporated in the NICE guideline [NG196], for Atrial fibrillation: diagnosis and management. Published: 27 April 2021.

References

1. Maheshwari A, Norby FL, Roetker NS, Soliman EZ, Koene RJ, Rooney MR, O’Neal WT, Shah AM, Claggett BL, Solomon SD, Alonso A, Gottesman RF, Heckbert SR, Chen LY. Refining Prediction of Atrial Fibrillation-Related Stroke Using the P₂-CHA₂DS₂-VASc Score. Circulation. 2019 Jan 8;139(2):180-191.
2. Soliman EZ, Prineas RJ, Case LD, Zhang ZM, Goff DC Jr. Ethnic distribution of ECG predictors of atrial fibrillation and its impact on understanding the ethnic distribution of ischemic stroke in the Atherosclerosis Risk in Communities (ARIC) study. Stroke. 2009 Apr;40(4):1204-11.
3. Bild DE, Bluemke DA, Burke GL, Detrano R, Diez Roux AV, Folsom AR, Greenland P, Jacob DR Jr, Kronmal R, Liu K, Nelson JC, O’Leary D, Saad MF, Shea S, Szklo M, Tracy RP. Multi-Ethnic Study of Atherosclerosis: objectives and design. Am J Epidemiol. 2002 Nov 1;156(9):871-81.
4. Watson T, Shantsila E, Lip GY. Mechanisms of thrombogenesis in atrial fibrillation: Virchow’s triad revisited. Lancet. 2009 Jan 10;373(9658):155-66.
5. Tsao CW, Josephson ME, Hauser TH, O’Halloran TD, Agarwal A, Manning WJ, Yeon SB. Accuracy of electrocardiographic criteria for atrial enlargement: validation with cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 2008 Jan 25;10(1):7.
6. Mitchell LB, Southern DA, Galbraith D, Ghali WA, Knudtson M, Wilton SB; APPROACH investigators. Prediction of stroke or TIA in patients without atrial fibrillation using CHADS2 and CHA2DS2-VASc scores. Heart. 2014 Oct;100(19):1524-30.