A preliminary study on the effects of exercise on vascular function by high frequency ultrasound / 中华医学超声杂志（电子版）

ABSTRACT

Objective To evaluate the effects of high frequency ultrasound in the assessment of vascular function during exercise in healthy subjects. Methods Forty-nine healthy subjects were enrolled in this study. The parameters of vascular function were measured at different stages (rest, exercise peak and recovery). Compliance coefficient (CC), distensibility coefficient (DC), stiffness indexα, stiffness indexβand pulse wave velocity (PWV) were measured by RF-Data technique of ultrasound vascular measurement (quantitative arterial stiffness, QAS). Endocardium-circumferential strain (EN-CS), epicardium-circumferential strain (EP-CS), endocardium-circumferential strain rate (EN-CSR) and epicardium-circumferential strain rate (EP-CSR) were collected by two-dimensional speckle tracking imaging (X-strain). The correlation between EN-CS, EN-CSR, EP-CS, EP-CSR and CC, DC, stiffness indexα, stiffness indexβand PWV were analyzed. Results At different stages (rest, exercise peak and recovery), CC were (1.436±0.448), (1.041±0.432) and (1.191±0.467) mm2/kPa DC were (0.040±0.016), (0.031±0.013) and (0.034±0.013) 1/kPa. CC and DC signiifcantly decreased at exercise peak (F=12.99 and 7.65, both P<0.01). At different stages (rest, exercise peak and recovery), PWV were (5.037±0.798), (5.845±1.165) and (5.683±1.367) m/s, stiffness indexαwere 2.298±0.633, 3.303±1.697 and 3.092±1.533, stiffness index β were 4.762±1.284, 6.794±2.515 and 6.158±3.089. PWV, stiffness index α and stiffness index β significantly increased at exercise peak (F=9.21, 13.24 and 12.33, all P<0.01). At different stages (rest, exercise peak and recovery), EN-CS were (7.825±2.445)%, (9.105±4.234)%and (6.271±2.527)%, EN-CSR were (0.831±0.276), (1.219±0.556) and (0.765±0.282) s-1, EP-CS were (6.894±2.465)%, (7.936±3.628)%and (5.489±2.306)%, EP-CSR were (0.714±0.247), (1.019±0.414) and (0.656±0.237) s-1. EN-CS, EN-CSR, EP-CS and EP-CSR signiifcantly increased at exercise peak (F=25.92, 43.76, 21.22 and 47.98, all P<0.01). EN-CS, EN-CSR, EP-CS and EP-CSR were positively correlated with PWV, stiffness indexαand stiffness indexβ(rfrom 0.253 to 0.494, all P<0.05), negatively correlated with CC and DC (rfrom-0.234 to-0.562, all P<0.05). Conclusions CC, DC, stiffness indexα, stiffness indexβ, PWV, EN-CS, EN-CSR, EP-CS and EP-CSR all can relfect the changes of vascular function during exercise. Properly exercise has positively direct effect on vascular elasticity.