Prognostic implications of functional significance, high-risk plaque and vessel characteristics in patients with diabetes mellitus.

BACKGROUND/AIMS: We investigated the prognostic value of high-risk plaque (HRP) and high-risk vessel (HRV) characteristics on coronary computed tomography angiography (CCTA) alongside fractional flow reserve (FFR) in patients with diabetes mellitus (DM). METHODS: We analyzed 307 vessels from 184 diabetic patients who underwent both CCTA and invasive FFR. HRP was defined as the presence of ≥ 3 high-risk features (minimal lumen area < 4 mm2, plaque burden ≥ 70%, low-attenuation plaque, positive remodeling, spotty calcification, or napkin-ring sign). HRV was defined as the presence of ≥ 1 quantitative volumetric parameter above the optimal cutoff. The primary endpoint was target vessel failure (TVF). HRs were adjusted for FFR, HRP, HRV, and the number of clinical risk factors. RESULTS: Functional significance (FFR ≤ 0.80; adjusted HR 2.56; 95% CI 1.07-6.12; p = 0.034), HRP (adjusted HR 2.29; 95% CI 1.10-4.77; p = 0.028), and HRV (adjusted HR 2.37; 95% CI 1.12-5.01; p = 0.025) were independent predictors of TVF. Notably, deferred vessels with FFR > 0.80 harboring HRP and/or HRV had a significantly higher risk of TVF compared to the deferred low-risk group (HR 4.78; 95% CI 1.68-13.57; p = 0.003), and their prognosis was comparable to that of deferred vessels with functional significance (FFR ≤ 0.80; HR 5.57; 95% CI 1.70-18.24; p = 0.005). CONCLUSION: In patients with DM, both lesion-level (HRP) and vessel-level (HRV) characteristics provided incremental prognostic value beyond FFR. Integrating these anatomical risk features may refine risk stratification for diabetic patients, particularly for those with functionally insignificant lesions.