Multisite Atherosclerosis and SCORE2-Based Risk Stratification in Psoriatic Arthritis: A Phenotype-Dependent Role of Vascular Territories

Background: Cardiovascular (CV) risk is increased in psoriatic arthritis (PsA), yet vascular assessment has largely focused on carotid arteries, potentially underestimating systemic atherosclerosis. Objective: The objective of this study was to characterize the distribution and concordance of atherosclerotic plaques across carotid, femoral, and aortic territories in PsA and evaluate their incremental value over SCORE2. Methods: In this cross-sectional study, 250 unselected patients with PsA underwent carotid and femoral ultrasound and abdominal X-ray. Plaque prevalence and multiterritorial involvement (≥2 vascular beds) were assessed. Agreement between territories was evaluated using Cohen’s κ. In patients aged 50–69 years, the incremental value of vascular territories over SCORE2 was evaluated using ROC curves, bootstrap-corrected decision curve analysis (DCA), and reclassification metrics (IDI and continuous NRI). Results: Plaques were detected in carotid (36.0%), femoral (62.8%), and aortic (31.6%) territories, with multiterritorial involvement in 43.2%. Agreement between vascular beds was moderate (κ ≈ 0.35). Notably, 48.1% of patients without carotid plaques had femoral involvement. SCORE2 categories showed a strong gradient with plaque prevalence (p < 0.0001). In patients aged 50–69 years, adding vascular imaging improved discrimination for multiterritorial disease (AUC 0.73 vs. 0.86–0.90). Reclassification analyses demonstrated that carotid plaque substantially improved the identification of multiterritorial atherosclerosis (IDI 0.32, 95% CI 0.18–0.50; continuous NRI 1.33, 95% CI 1.08–1.60), with similar results observed for aortic plaque (IDI 0.33, 95% CI 0.20–0.50; continuous NRI 1.24, 95% CI 0.99–1.48). Femoral plaque provided a more modest improvement (IDI 0.26, 95% CI 0.16–0.37; continuous NRI 1.11, 95% CI 0.80–1.33). Conversely, when the outcome was defined as the presence of any plaque, femoral plaque provided the greatest incremental value over SCORE2 (AUC 0.96, 95% CI 0.93–0.99). Bootstrap-corrected DCA confirmed improved net benefit. Conclusions: The incremental value of vascular imaging over SCORE2 appears to be phenotype-dependent. Femoral plaque provided the greatest improvement for detecting the presence of subclinical atherosclerosis, whereas carotid and aortic plaques offered greater incremental value for identifying multiterritorial vascular involvement. These findings support a tailored, multiterritorial approach to cardiovascular risk assessment in patients with PsA.