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. 2023 Nov 7;12(21):e030757.
doi: 10.1161/JAHA.123.030757. Epub 2023 Oct 27.

Validating the SMART2 Score in a Racially Diverse High-Risk Nationwide Cohort of Patients Receiving Coronary Artery Bypass Grafting

Salil V Deo  1   2   3 , Andrew Althouse  4   5 , Sadeer Al-Kindi  2   6 , David A McAllister  3 , Ariela Orkaby  7   8 , Yakov E Elgudin  1   2 , Stephen Fremes  9 , Danny Chu  10 , Frank L J Visseren  11 , Jill P Pell  3 , Naveed Sattar  12
Affiliations

Validating the SMART2 Score in a Racially Diverse High-Risk Nationwide Cohort of Patients Receiving Coronary Artery Bypass Grafting

Salil V Deo et al. J Am Heart Assoc. .

Abstract

Background We tested the potential of the Secondary Manifestations of Arterial Disease (SMART2) risk score for use in patients undergoing coronary artery bypass grafting. Methods and Results We conducted an external validation of the SMART2 score in a racially diverse high-risk national cohort (2010-2019) that underwent isolated coronary artery bypass grafting. We calculated the preoperative SMART2 score and modeled the 5-year major adverse cardiovascular event (cardiovascular mortality+myocardial infarction+stroke) incidence. We evaluated SMART2 score discrimination at 5 years using c-statistic and calibration with observed/expected ratio and calibration plots. We analyzed the potential clinical benefit using decision curves. We repeated these analyses in clinical subgroups, diabetes, chronic kidney disease, and polyvascular disease, and separately in White and Black patients. In 27 443 (mean age, 65 years; 10% Black individuals) US veterans undergoing coronary artery bypass grafting (2010-2019) nationwide, the 5-year major adverse cardiovascular event rate was 25%; 27% patients were in high predicted risk (>30% 5-year major adverse cardiovascular events). SMART2 score discrimination (c-statistic: 64) was comparable to the original study (c-statistic: 67) and was best in patients with chronic kidney disease (c-statistic: 66). However, it underpredicted major adverse cardiovascular event rates in the whole cohort (observed/expected ratio, 1.45) as well as in all studied subgroups. The SMART2 score performed better in White than Black patients. On decision curve analysis, the SMART2 score provides a net benefit over a wide range of risk thresholds. Conclusions The SMART2 model performs well in a racially diverse coronary artery bypass grafting cohort, with better predictive capabilities at the upper range of baseline risk, and can therefore be used to guide secondary preventive pharmacotherapy.

Keywords: atherosclerotic vascular disease; coronary artery bypass grafting; coronary artery disease; external validation; myocardial infarction; risk prediction.

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Figures

Figure 1
Figure 1. Proportion of patients in the risk groups according to the SMART2 5‐year MACE risk prediction.
CKD indicates chronic kidney disease; MACE, major adverse cardiovascular event; and SMART2, Secondary Manifestations of Arterial Disease.
Figure 2
Figure 2. The observed cumulative incidence for MACEs over the 5‐year study period according to the SMART2 risk groups.
MACEs indicates major adverse cardiovascular events; and SMART2, Secondary Manifestations of Arterial Disease.
Figure 3
Figure 3. Results of model discrimination c‐statistic for our study cohort compared against other published external validation data of the SMART2 score.
CABG indicates coronary artery bypass grafting; CKD, chronic kidney disease; CPRD, clinical practice research datalink; DM, diabetes; Nor‐COAST, Norwegian Cognitive Impairment After Stroke; REACH, The Reduction of Atherothrombosis for Continued Health Registry; SMART2, Secondary Manifestations of Arterial Disease; and VA, Department of Veterans Affairs.
Figure 4
Figure 4. Calibration plot, plotting the observed and estimated 5‐year MACEs for the whole cohort and in studied clinical subgroups (black line, observed/estimated [O/E] value; shaded band, 95% CI).
MACEs indicates major adverse cardiovascular events.
Figure 5
Figure 5. Calibration plot, plotting the observed and estimated 5‐year MACEs in White and Black patients (blue line, observed/estimated value; shaded band, 95% CI).
MACEs indicates major adverse cardiovascular events.
See this image and copyright information in PMC

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