Blood flow velocity in the carotid artery is associated with peripheral diastolic blood pressure and pulse pressure

Patients with atherosclerotic cerebrovascular disease appear to have larger common carotid arterial diameters and lower carotid flow velocities compared to those without the disease. The index of arterial stiffness is strongly related to the extent of atherosclerosis and cardiovascular events. The objective of this study was to elucidate the association between morphologic or hemodynamic parameters of the carotid artery and the vascular hemodynamic parameters of patients without atherosclerotic cardiovascular disease (ASCVD). From patients who underwent carotid ultrasonography and non-invasive, semi-automated, radial artery applanation tonometry (Omron HEM-9000AI) in the Department of Internal Medicine at St. Vincent’s Hospital from July 2011 to June 2015, 388 subjects (195 male, mean age, 55±12 years) without ASCVD were enrolled in this study. After multivariate analysis, diastolic blood pressure (BP) (β=-0.231, 95% CI -0.003 to 0.000, P=0.019) and peripheral pulse pressure (PP) (β=0.230, 95% CI 0.000 to 0.003, P=0.016) were found to be associated with the resistance index after adjusting for age, gender, body mass index, fasting plasma glucose, HbA1c, smoking, diabetes, hypertension and use of antihypertensive medication and lipid-lowering therapy. Additionally, diastolic BP (β=-0.189, 95% CI 0.001 to 0.208, P=0.047) was correlated with end-diastolic velocity. After multivariate analysis, Intima-media thickness and diameter were associated with several vascular hemodynamic parameters. Blood flow velocity of the carotid artery influences peripheral BP or PP rather than the index of arterial stiffness. However, morphological parameters are associated with arterial stiffness and systemic hemodynamic factors. Although further studies are required, multiparametric assessment might contribute to a better understanding of the structural, functional, and hemodynamic changes of the carotid artery.