Measurement of arterial stiffness in subjects with vascular disease: Are vessel wall changes more sensitive than increase in intima–media thickness?

Background and aims
It is widely accepted that subjects with vascular disease have increased arterial stiffness and intima–media thickness (IMT) when compared with healthy controls. The aim of this study was to investigate indices of arterial stiffness and IMT in the common carotid arteries (CCAs) of subjects with and without peripheral arterial disease (PAD), in order to look for evidence of change in wall quality and quantity to explain increased stiffness that has been found in the arteries of subjects with vascular disease.

Methods and results
The arterial distension waveform (ADW), IMT, diameter and brachial blood pressure were measured to calculate Young's Modulus (E) and elastic modulus (Ep) in the common carotid arteries of subjects with and without PAD. 38 subjects with confirmed PAD were compared with 43 normal controls matched for age, sex, smoking and hypertension. The mean diameter (8.35 mm [95% CI 7.93–8.77] vs. 6.93 mm [6.65–7.20] P < 0.001, increase 20%), IMT (0.99 mm [0.92–1.07] vs. 0.88 mm [0.82–0.93] P = 0.020, increase 12.5%), Ep (315 kPa [185–444] vs. 190 kPa [164–216] P = 0.034, increase 66%) and E (1383 kPa [836–1930] vs. 744 kPa [641–846] P = 0.006, increase 86%) were all significantly higher in subjects with PAD.

Conclusions
This study suggests that increased stiffness observed in subjects with peripheral vascular disease is a result of change in both quantity and quality of the arterial wall. Changes in indices of arterial stiffness were much higher than changes in IMT and diameter. These preliminary observations may be an indication that indices of arterial stiffness are a sensitive early marker of atherosclerosis.