Atherosclerosis: Carotid vessel wall thickness and aortic stiffness compared to stenosis class in peripheral arterial disease

Objective: Atherosclerosis is a systemic disease and involves arterial wall thickening and arterial wall stiffening. We hypothesized a closer link between arterial wall thickening and stiffening within the same vascular trajectory rather than across different trajectories. Therefore, the purpose of this study was to evaluate the site-specific relationship between peripheral arterial stenosis severity and markers for regional arterial wall thickness and stiffness, such as the cross-sectional vessel wall area (VWA) sampled in the left common carotid artery and the pulse wave velocity (PWV) sampled in the proximal and distal aorta using a comprehensive 3T MRI protocol. Methods: Thirty-four patients (19 men; mean age 62 years) with clinically suspected peripheral arterial disease (PAOD) were included. The peripheral arterial tree was imaged by CE-MRA from the infrarenal aorta down to the distal run-off at 3T MRI (Achieva, Philips) with intra-venous infusion of 0.1 mmol/kg body weight gadoterate meglumine (Dotarem, Guerbet). For evaluation, the arterial tree was divided into 27 segments and stenoses were visually graded on 5-point scale (1: 0% stenosis; 2: 1–50% stenosis; 3: 51–75% stenosis; 4: 76–99% stenosis; 5: 100% occlusion). Per patient, the mean and maximal stenosis class (SC) was determined. The mean carotid VWA was assessed and indexed for body surface area (BSA). PWV was determined for the proximal and distal aorta by applying two one-directional through-plane velocity-encoded MRI acquisitions with high temporal resolution. Results: Average Mean SC per patient was 1.6 ± 0.4, average Max SC per patient was 4.4 ± 1.0. Mean PWV in proximal aorta was 8.3 ± 2.3 m/s and in distal aorta 8.5 ± 2.5 m/s. Mean carotid VWA/BSA was 2.9 ± 1.0 mm2/m2. Spearman correlation between Mean SC and proximal aorta PWV was 0.19 (p = 0.25), for distal aorta PWV 0.74 (p < 0.001) and for carotid VWA/BSA 0.54 (p < 0.001). Spearman correlation between carotid VWA/BSA and proximal aorta PWV was 0.15 (p = 0.37) and for distal aorta PWV 0.41 (p = 0.01). Only the correlation between Mean SC and distal aorta PWV remained significant after correction for age (Table 1). Conclusions: In patients with PAOD, mean and maximum peripheral stenosis severity is strongly correlated with PWV in the distal aorta as compared to carotid VWA, while correlation with PWV in the proximal aorta is absent. Our findings indicate site-specific coupling between aortic wall stiffness and atherosclerotic burden.