Arterial Stiffness as a Biomarker of Radiation-Induced Carotid Atherosclerosis

Abstract

Arterial stiffness is thought to be a precursor to atherosclerosis. Conventional arterial stiffness parameters as potential biomarkers of radiation-induced damage were investigated. Patients with head and neck cancer treated with radiotherapy ≥2 years previously to one side of the neck were included. The unirradiated side was the internal control. Beta stiffness index (B) and elastic modulus ( Ep) were used to assess arterial stiffness and were measured in proximal, mid, and distal common carotid artery (CCA) and compared with the corresponding unirradiated segments. Fifty patients (68% male; median age 58 years; interquartile range 50-62) were included. Mean ± standard deviation maximum doses to irradiated and unirradiated arteries were 53 ± 13 and 1.9 ± 3.7 Gy, respectively. Differences in B were not significant. Significant differences in Ep were demonstrated—proximal CCA: 1301 ± 1223 versus 801 ± 492 ( P < .0001), mid CCA: 1064 ± 818 versus 935.5 ± 793 ( P < .0001), and distal CCA: 1267 ± 1084 versus 775.3 ± 551.9 ( P < .0001). Surgery had no impact on arterial stiffness. Arterial stiffness is increased in irradiated arteries, in keeping with radiation-induced damage. Prospective data may show an association between arterial stiffness and atherosclerosis in this setting.