Beyond stenosis: imaging phenotyping and risk stratification in nonobstructive coronary artery disease

Nonobstructive coronary artery disease (NOCA) is now frequently detected by coronary CT angiography (CCTA), but the term compresses biologically distinct patterns into a single anatomic label. This review examines how CT-derived markers can reorganize NOCA around plaque burden, inflammatory activity, clinical expression, and temporal change.

Recent work distinguishes three related but distinct tasks in NOCA: identify disease, stratify risk, and define phenotypes that may inform future prevention strategies. CCTA addresses the atherosclerotic and prognostic dimensions by quantifying plaque burden, plaque composition, and high-risk features; CT-derived inflammatory and cardiometabolic markers may further identify active vascular and metabolic phenotypes. In symptomatic patients, CCTA and fractional flow reserve CT can evaluate epicardial anatomy and lesion-specific hemodynamic significance, but normal or nonobstructive findings do not exclude coronary microvascular dysfunction or vasospasm. In asymptomatic patients, coronary artery calcium and CCTA can reveal subclinical atherosclerosis and refine preventive risk assessment. Serial imaging and intervention studies suggest that adverse plaque phenotypes can stabilize or change with intensive prevention, but outcome-proven CCTA-guided treatment algorithms are still lacking.

CCTA is evolving into a multidimensional phenotyping tool for NOCA. Its immediate value is refined risk stratification; whether these markers will improve outcomes remains unproven and should be tested prospectively.