Carotid perivascular adipose tissue attenuation predicts stroke and TIA in symptomatic carotid artery disease patients

Background: Vascular inflammation is a key aspect of plaque vulnerability. Cross-sectional studies suggest that increased carotid perivascular adipose tissue (PVAT) attenuation on CTA, which is thought to reflect vascular inflammation, is associated with stroke. Objectives: We investigated the predictive value of carotid PVAT attenuation for ischemic stroke and TIA in a longitudinal study of symptomatic patients with carotid plaque. Methods: We included patients with recent TIA or stroke and a ≥2 ​mm carotid plaque with <70 ​% stenosis who underwent CTA and MRI and were clinically followed-up for 5 years. Mean PVAT attenuation (−190 to −30 Hounsfield Units (HU)) was quantified within a radial distance from the outer vessel wall equal to the vessel diameter on the CTA slice containing the thickest plaque. Cox proportional hazards models assessed associations with ipsilateral stroke and TIA risk. Predictive value was compared with intraplaque hemorrhage (IPH) and the European Carotid Surgery Trial (ECST) score using the C-index. Results: Among 159 patients (74 ​% men; 69 (63–73) years), 11 ischemic strokes and 10 TIAs occurred over 5.1 (3.1–5.6) years. Increased PVAT attenuation was independently associated with ischemic stroke or TIA (HR: 3.21 per 10 HU increase, 95%CI:1.70–6.05) and ischemic stroke alone (HR: 5.60, 95%CI:1.93–16.31). PVAT attenuation alone predicted ischemic stroke or TIA (C-index: 0.71, 95%CI:0.70–0.73) and ischemic stroke alone (C-index: 0.78, 95%CI:0.63–0.93). Adding PVAT attenuation improved prediction beyond IPH (C-index: 0.66–0.68 to 0.81–0.84) and the ECST score (0.64–0.75 to 0.75–0.86, respectively). Conclusion: In symptomatic patients, PVAT attenuation is an independent marker for ischemic stroke and TIA risk.