Coronary atherosclerosis, myocardial perfusion, and interstitial fibrosis between diabetic and nondiabetic patients with stable chest pain: a propensity score matching study.

OBJECTIVES: To evaluate the effect of diabetes mellitus on coronary atherosclerosis, myocardial perfusion, and interstitial fibrosis using cardiac CT. METHODS: This study included 409 diabetic patients with stable chest pain who prospectively underwent coronary CT angiography (CCTA), stress CT myocardial perfusion imaging (CT-MPI), and late iodine enhancement (LIE). Additionally, 413 symptomatic non-diabetic patients were retrospectively enrolled as controls. Propensity score matching (1:1) was performed based on cardiovascular risk factors. Cardiac CT parameters including coronary artery calcium score, stenosis extent, high-risk plaque features, stress myocardial blood flow, and myocardial fibrosis were compared. RESULTS: Diabetic patients exhibited lower global stress myocardial blood flow [143.1 vs. 147.2 ml/100 ml/min; p = 0.001] and a higher incidence of myocardial ischemia (43.8% vs. 31.3%; p = 0.003). Diabetes remained an independent predictor of ischemia [odds ratio: 2.070; 95% confidence interval: 1.413-3.033; p < 0.001]. In CAD-RADS 0 patients, diabetes was associated with higher ischemia rates (33.7% vs. 14.5%; p = 0.004), and in CAD-RADS 1-2 patients, with more frequent napkin-ring signs (NRS) (10.3% vs. 3.5%; p = 0.042). Coronary calcification and myocardial fibrosis showed no significant difference between groups. CONCLUSIONS: Diabetes is associated with impaired myocardial perfusion. Even in the absence of coronary atherosclerosis, diabetic patients have a higher prevalence of myocardial ischemia. In patients with nonobstructive CAD, diabetes was associated with a higher frequency of NRS. ADVANCES IN KNOWLEDGE: Diabetes is associated with myocardial perfusion deficits and high-risk plaque independent of other cardiovascular risk determinants.