Predicting silent cerebral microischemia in patients with non-valvular atrial fibrillation and structurally normal hearts: the CHADS2, CHA2DS2-VASc and -R scores

Abstract

Purpose: To evaluate the ability of the CHADS2 and CHA2DS2-VASc scores alone and combined with creatinine clearance (CrCl) to predict silent cerebral lesions in patients with non-valvular atrial fibrillation (AF) and structurally normal hearts. Methods: Magnetic resonance brain imaging (MRI) was performed in consecutive patients initially diagnosed with first-diagnosed lone AF. Patients with prior AF ablation were excluded. In addition to the classic scores, the CHADS2-R and CHA2DS2-VASc-R were calculated by adding 1 point for CrCl≤90ml/min. Results: Of 33 patients aged 54.4±14.4y, 26 were males (78.8%) and 15 (45.5%) had paroxysmal AF. Mean systolic and diastolic blood pressures were 118.2±12.7 and 74.4±7.9 mmHg, respectively, mean CrCl was 110.9±27.5 mL/min, and mean LVEF 61.9±5.8%. Mean score values were: CHADS2 0.67±1.02, CHA2DS2-VASc 1.03±1.05, CHADS2-R 0.9±1.2 and CHA2DS2-VASc-R 1.3±1.8. Mean 13.7±8.2 years from first AF, 15 patients (45.5%) remained lone AF, 5 (15.1%) aged >60, 12 (36.4%) developed hypertension (plus coronary disease, 1 patient) and 1 (3.0%) developed pulmonary disease; 4 patients had suffered symptomatic ischemic stroke; 17 (51.5%) were taking oral anticoagulation (5 awaiting cardioversion). MRI detected silent microischemia in 17 patients (51.5%), microangiopathy in 4 (12.1%) and no microbleeds; microischemic lesions were detected in 5/15 patients (33.3%) with lone AF and 12/18 (66.7%) with hypertension, p=0.059. On the univariate logistic regression the CHADS2, CHA2DS2-VASc, CHADS2-R and CHA2DS2-VASc-R were all significantly related to microischemia (OR 5.7; 95% CI, 1.3-25.9; p=0.023, 4.7; 95% CI, 1.3-16.4; p=0.016, 5.3; 95% CI, 1.4-19.8; p=0.014 and 4.6; 95% CI, 1.4-14.9; p=0.011, respectively). On the multivariable analysis, only the CHA2DS2-VASc-R was significantly related to cerebral microischemia (OR 3.7; 95% CI, 1.2-11.8; p=0.027). The prediction ability (c-statistic) of the CHADS2, CHA2DS2-VASc, CHADS2-R and CHA2DS2-VASc-R scores was 0.72; 95% CI, 0.53-0.91; p=0.040, 0.75; 95% CI, 0.58-0.93; p=0.018, 0.78; 95% CI,0.62-0.96; p=0.007 and 0.80; 95% CI, 0.63-0.96; p=0.006, respectively. Conclusions: The inclusion of the CrCl cut-off value reflecting even subtle renal dysfunction improved the prediction ability of the thromboembolic risk scores for silent cerebral microischemic lesions in AF patients with lone AF or hypertension and structurally normal hearts, who are often perceived as low risk population. Compared with the CHADS2 and CHADS2-R, the CHA2DS2-VASc and CHA2DS2-VASc-R scores, respectively, had better prediction ability for the presence of silent cerebral lesions in these AF patients.