Impact of Coronary Artery Disease Extent on GRACE Risk Score Prognostic Performance After ST-Segment-Elevation Myocardial Infarction.

BACKGROUND: The GRACE (Global Registry of Acute Coronary Events) score is well validated for risk stratification in non-ST-segment-elevation myocardial infarction, but less well established in ST-segment-elevation myocardial infarction (STEMI), particularly relative to coronary disease burden. We therefore assessed its prognostic performance in a STEMI cohort, accounting for baseline coronary disease extent. METHODS: We studied 1099 patients with STEMI from the CardioLines Coronary Biobank (2015-2021) with evaluable GRACE score and follow-up data. Patients were stratified by the number of coronary vessels with significant stenosis. The primary end point was all-cause death at 1 year; the secondary end point was a combined end point, including all-cause death, recurrent acute coronary syndrome, stroke, and revascularization at 1 year. In multivariable models, each 10-point increase in GRACE score was associated with a 31% higher risk of all-cause death and a 14% higher risk of the combined end point at 1 year. In single-vessel disease, discrimination for all-cause death was excellent early (30-day area under the curve, 0.874 [95% CI, 0.755-0.991]) and moderate at 1 year (area under the curve, 0.77 [95% CI, 0.613-0.927]), but consistently poor in 3-vessel disease (area under the curve, 0.52-0.57). Discrimination was significantly higher in single- versus multivessel disease at earlier time points, with differences attenuated by 1 year. Stratified regression analyses confirmed stronger associations in single-vessel versus multivessel disease. CONCLUSIONS: In this contemporary STEMI cohort, the GRACE score effectively stratifies event risk in single-vessel but performs poorly in multivessel disease. These findings suggest variable prognostic utility of the GRACE score across anatomic disease burden post-STEMI and caution when applying it across STEMI subgroups.