The following is a summary of “Validating the SMART2 Score in a Racially Diverse High‐Risk Nationwide Cohort of Patients Receiving Coronary Artery Bypass Grafting,” published in the October 2023 issue of Cardiology by Deo et al.

This study investigated the potential of the Secondary Manifestations of Arterial Disease (SMART2) risk score as a predictive tool for patients undergoing coronary artery bypass grafting (CABG). The researchers externally validated the SMART2 score using a racially diverse, high-risk national cohort that underwent isolated CABG between 2010 and 2019. 

Utilizing the preoperative SMART2 score, the study group assessed the 5-year incidence of major adverse cardiovascular events (including cardiovascular mortality, myocardial infarction, and stroke). The discriminatory ability of the SMART2 score at 5 years was evaluated using the c-statistic, calibration through observed/expected ratios and calibration plots, and clinical benefit assessment via decision curves. Subgroup analyses were performed among patients with diabetes, chronic kidney disease, and polyvascular disease, as well as separately among White and Black patients. Among 27,443 US veterans undergoing CABG, the 5-year major adverse cardiovascular event rate was 25%, with 27% classified as high risk (>30% 5-year major adverse cardiovascular events). The SMART2 score demonstrated comparable discrimination (c-statistic: 64) to the original study (c-statistic: 67), exhibiting the best performance in patients with chronic kidney disease (c-statistic: 66). 

However, it consistently underestimated major adverse cardiovascular event rates in the entire cohort and all examined subgroups. Notably, the SMART2 score exhibited superior predictive performance in White compared to Black patients. Decision curve analysis illustrated the SMART2 score’s net benefit across various risk thresholds. Their findings suggest that while the SMART2 model performs well in a diverse CABG cohort, its enhanced predictive capacity is observed particularly in higher-risk groups, making it valuable in guiding secondary preventive pharmacotherapy.

Source: ahajournals.org/doi/10.1161/JAHA.123.030757