Stress Hyperglycemia Ratio Outperforms Admission Glucose in Predicting Coronary Slow Flow in Patients with Type 2...

The coronary slow flow phenomenon (CSFP) is delayed contrast progression through the epicardial coronary arteries in the absence of significant stenosis. The stress hyperglycemia ratio (SHR) normalizes admission glucose to the estimated average glucose derived from HbA1c, separating acute glycemic excursion from chronic hyperglycemia. Whether the SHR is independently associated with CSFP in patients with type 2 diabetes mellitus (T2DM) is not known.

This retrospective case-control study enrolled 235 consecutive patients with T2DM who underwent coronary angiography between January 2022 and January 2025. Patients with epicardial stenosis exceeding 40% in any vessel, prior revascularization, or acute coronary syndrome within 30 days were excluded. Among the remaining patients, those with a corrected TIMI frame count (CTFC) above 27 in any epicardial vessel were classified as CSFP (n=112) and the rest as normal coronary flow (NCF) (n=123). The SHR was calculated as admission blood glucose (mmol/L) divided by (1.59 × HbA1c% - 2.59).

The SHR was higher in the CSFP group than in the NCF group (1.42 ± 0.31 vs. 1.08 ± 0.24, p<0.001). After multivariate adjustment, it remained independently associated with CSFP (odds ratio [OR] 2.84, 95% confidence interval [CI] 1.92-4.21, p<0.001). On receiver operating characteristic analysis the area under the curve (AUC) was 0.819 (95% CI 0.760-0.876); a cutoff of 1.21 gave 78.6% sensitivity and 74.0% specificity. The SHR correlated with mean CTFC (r=0.621, p<0.001) and outperformed admission glucose alone (AUC 0.724, p=0.003).

In this cohort, the SHR was independently associated with CSFP and discriminated it better than admission glucose alone. Because it is calculated from two values routinely available at catheterization, admission glucose and HbA1c, the SHR is a practical candidate marker that warrants prospective validation for risk stratification in patients with T2DM undergoing coronary evaluation.