Assessment of carotid elasticity during exercise: a reproducibility study

The study aimed to evaluate the reproducibility of carotid elasticity during exercise. Eighteen healthy volunteers (nine males, age 34 ± 3 years, BMI 22 ± 6 kg/m(2)) underwent maximal exercise testing on a graded semi-supine cycle ergometer in two different sessions 3 days apart. Ultrasound B-mode image sequences of the right common carotid were acquired at different steps and analyzed by an automatic system; pressures were estimated by tonometry. Compliance (CC) and distensibility (DC) were significantly decreased at exercise peak and in the first recovery minute (CC from 1.6 ± 0.8 to 1 ± 0.6 mm^(2)/KPa, DC from 56.2 ± 25.3 to 34.5 ± 20 10^(-3)/KPa, p < 0.05). For the whole examination, intraclass coefficient was 0.780 for CC and 0.694 for DC. Mean coefficient of variation was maximum at peak exercise (CC = 19 ± 6%, DC = 24 ± 15%), but at first minute of recovery it was comparable to resting values (CC = 12 ± 9%, DC = 12 ± 11%). When designing future studies, acquisitions during first recovery minute might be preferred to peak measures.