Normal myocardial perfusion may not be reassuring in individuals with diabetes and suspected coronary artery disease (CAD). A study published in Cardiovascular Diabetology shows that coronary plaque burden measured by computed tomography strongly predicts cardiovascular risk, even when stress perfusion appears normal.

This observational cohort included 1,311 symptomatic adults referred for coronary computed tomography angiography (CTA) and [15O]H₂O positron emission tomography (PET) perfusion imaging. Coronary plaque burden was quantified using artificial intelligence–derived percent atheroma volume (PAV). Abnormal regional stress myocardial blood flow (sMBF) was defined as ≥2 adjacent segments with sMBF < 2.3 mL/g/min. The composite endpoint included all-cause death, myocardial infarction (MI), or unstable angina pectoris (UAP) during 7 years of follow-up.

Among all patients, 19% had diabetes, and 10% experienced an adverse event. The annual event rate was 0.8% (95% CI 0.6–1.1%) in non-diabetic individuals with normal perfusion. Rates increased to 2.3% in the presence of diabetes, 2.6% with abnormal perfusion, and 3.2% when both were present (P < .001). Even among those with normal perfusion, patients with diabetes had double the plaque burden compared with non-diabetic individuals (median PAV 8.2% vs 4.1%, P < .001).

Multivariable Cox analysis showed PAV independently predicted outcomes in both diabetes and non-diabetes groups (HR 1.03 per 1% increase; P < .001). sMBF was an independent predictor only in non-diabetic patients (HR 1.04 per 0.1 mL/g/min decrease; P = .016).

These findings highlight that plaque burden is a key driver of long-term cardiovascular risk. In individuals with diabetes, preserved myocardial perfusion does not necessarily indicate clinical stability due to persistent atherosclerotic progression.