Repeatability and reproducibility of pulse wave velocity in relation to hemodynamics and sodium excretion in stable patients with hypertension.

Abstract

Pulse wave velocity (PWV) is a useful marker for determining subclinical vascular damage and patient risk stratification. Repeatability and reproducibility of PWV in relation to influencing factors have not yet been determined. This study examined the repeatability and reproducibility of PWV, and whether hemodynamics and sodium excretion impact on PWV in hypertensive patients remaining on stable medication. Office blood pressure (BP), heart rate (HR), carotid--femoral PWV and central BP (SphygmoCor device), impedance cardiography (HOTMAN device) and 24-h urinary sodium excretion (UNa) were measured at baseline and after 4 weeks in 74 hypertensive patients (age 56.8 ± 11.5 years, mean ± SD). Two PWV measurements were performed at each visit. Intraclass correlation coefficient (ICC) and 95% confidence interval (95% CI) between the two PWV measurements were 0.981 (0.970--0.988) at baseline, 0.975 (0.960--0.984) after 4 weeks and 0.851 (0.773--0.903) between both visits. There were no significant changes in BP, HR, thoracic fluid content, stroke volume and UNa between visits. Despite excellent ICC, reproducibility of PWV was related to BP (P < 0.001) and HR (P = 0.07) changes between visits. Nineteen out of 74 patients had a difference in PWV greater than ±1 m/s between both visits. In the medium-term observation, changes in BP and HR seem to affect PWV values. Our findings suggest that the assessment of PWV should be performed under stabilized BP and HR values, particularly in patients with newly diagnosed hypertension and/or low--moderate cardiovascular risk in whom the detection of asymptomatic hypertension-mediated organ damage impact on patient risk stratification.