Is 6-month GRACE risk score a useful tool to predict stroke after an acute coronary syndrome?

OBJECTIVES The risk of stroke after an acute coronary syndrome (ACS) has increased. The aim of this study was to do a comparative validation of the 6-month GRACE (Global Registry of Acute Coronary Events) risk score and CH2DS2VASc risk score to predict the risk of post-ACS ischaemic stroke. METHODS This was a retrospective study carried out in a single centre with 4229 patients with ACS discharged between 2004 and 2010 (66.9±12.8 years, 27.9% women, 64.2% underwent percutaneous coronary intervention). The primary end point is the occurrence of an ischaemic stroke during follow-up (median 4.6 years, IQR 2.7-7.1 years). RESULTS 184 (4.4%) patients developed an ischaemic stroke; 153 (83.2%) had sinus rhythm and 31 (16.9%) had atrial fibrillation. Patients with stroke were older, with higher rates of hypertension, diabetes, previous stroke and previous coronary artery disease. The HR for CHA2DS2VASc was 1.36 (95% CI, 1.27 to 1.48, p<0.001) and for GRACE, HR was 1.02(95% CI, 1.01 to 1.03, p<0.001). Both risk scores show adequate discriminative ability (c-index 0.63±0.02 and 0.60±0.02 for CHA2DS2VASc and GRACE, respectively). In the reclassification method there was no difference (Net Reclassification Improvement 1.98%, p=0.69). Comparing moderate-risk/high-risk patients with low-risk patients, both risk scores showed very high negative predictive value (98.5% for CHA2DS2VASc, 98.1% for GRACE). The sensitivity of CHA2DS2VASc score was higher than the GRACE risk score (95.1% vs 87.0%), whereas specificity was lower (14.4% vs 30.2%). CONCLUSIONS The 6-month GRACE model is a clinical risk score that facilitates the identification of individual patients who are at high risk of ischaemic stroke after ACS discharge.