Defining the Role of Duplex Ultrasound Assessment to Determine Severity of Arterial Calcification: An Analysis of the Superficial Femoral Artery

Abstract

Lower limb arterial calcification associates with poor cardiovascular outcomes. The gold standard method of assessment is via computed tomography, yet duplex is our primary imaging modality. Currently, there is no standardized objective assessment of lower limb arterial calcification using duplex. We aimed to define the role of duplex in the assessment of lower limb arterial calcification. Initial consensus was achieved between a cohort of vascular scientists on objective imaging specific markers of lower limb arterial calcification severity using duplex. This resulted in objective descriptions to grade calcification from 0 to 3 (no calcification through to severe calcification) which formed the duplex lower limb arterial calcification score. Reproducibility of the duplex lower limb arterial calcification score was assessed and further validation was undertaken by comparing the duplex lower limb arterial calcification with computed tomography–based assessment in a separate cohort of 44 patients investigated with both modalities. The intra- and inter-class correlation coefficient were > 0.87 . The Spearman rank correlation coefficient between the duplex and CT based arterial calcium measurements was (ρ = 0.644, P < .001). The duplex lower limb arterial calcification score provides a standardized and reproducible modality for assessment of lower limb arterial calcification and may aid with risk stratification in patients with peripheral arterial disease.