Pericoronary adipose tissue attenuation on CCTA as a marker of cardiovascular risk: A systematic review and meta-analysis.

BACKGROUND: Pericoronary adipose tissue (PCAT) attenuation on coronary computed tomography angiography (CCTA) reflects local vascular inflammation, but its prognostic performance across heterogeneous imaging protocols and follow-up durations remains uncertain. METHODS: MEDLINE via Pubmed, Scopus, and Cochrane were searched through June 2025 for longitudinal CCTA studies reporting multivariable-adjusted associations between attenuation-based PCAT metrics and major adverse cardiovascular events (MACE). Hazard ratios (HRs) were standardized to a per-1-Hounsfield unit (HU) scale and pooled using random-effects models, with estimates presented per 5 HU. Follow-up was stratified as short (≤3 years), intermediate (>3-5 years), and long-term (≥5 years). Studies evaluating fat attenuation index (FAI), change in FAI (ΔFAI), thresholds, or artificial intelligence (AI)-derived perivascular metrics were synthesized qualitatively. RESULTS: Seventeen studies (n = 57,862) met inclusion criteria; seven cohorts (n = 5,922) contributed to the HU-based meta-analysis. Higher PCAT attenuation was associated with increased MACE risk (HR 1.29 per 5 HU; 95 % confidence interval [CI] 1.09-1.53; I2≈84 %). Across follow-up strata, effect estimates remained directionally consistent: short-term HR 1.22 per 5 HU (95 % CI 1.04-1.43), intermediate-term HR 1.38 (95 % CI 0.98-1.95), and long-term HR 1.50 (95 % CI 0.86-2.62), without significant between-group differences. Subgroup analyses showed similar effect sizes in studies using standardized right coronary artery (RCA) PCAT versus lesion-specific or multivessel approaches. Ten additional studies evaluating FAI, ΔFAI, HU thresholds, or composite or AI-based metrics showed higher risk with more inflamed perivascular attenuation phenotypes. CONCLUSION: Higher PCAT attenuation is associated with increased MACE risk across diverse imaging platforms and follow-up horizons and appears to be a marker of inflammation-related coronary vulnerability.