Disparate Information Provided by Pulse Wave Velocity versus Other Measures of Aortic Compliance in End-Stage Renal Disease

Abstract

Introduction: Unfavorable changes in cardiac and arterial function are related to poor prognosis in chronic kidney disease (CKD). We compared hemodynamic profiles between subjects with end-stage renal disease and 2 control groups with corresponding pulse wave velocities (PWVs). Methods: Noninvasive hemodynamics were recorded during passive head-up tilt in CKD stage 5 patients (n = 35), patients with primary hypertension (n = 35, n = 30 with antihypertensive medications), and subjects without cardiovascular or renal diseases and cardiovascular medications (n = 70). The groups were selected to have corresponding age, sex, body mass index, and PWV. Hemodynamic data were captured using whole-body impedance cardiography and radial tonometric pulse wave analysis. Results: Supine blood pressure did not differ between the groups, but upright diastolic blood pressure was lower in CKD patients than in the 2 control groups (p ≤ 0.001 for both, RANOVA). Despite similar PWV, supine aortic pulse pressure was higher in CKD patients versus nonmedicated subjects (p = 0.029). Two additional measures indicated reduced aortic compliance in CKD patients versus both control groups: lower ratio of stroke index to aortic pulse pressure (p ≤ 0.023) and higher aortic characteristic impedance (p ≤ 0.003). The subendocardial viability ratio was lower in the CKD group than in both control groups (p ≤ 0.039). Conclusion: In the absence of differences in PWV, higher aortic pulse pressure and characteristic impedance, and lower ratio of stroke index to aortic pulse pressure, suggest reduced aortic compliance and impaired left ventricular function in CKD patients. A lower subendocardial viability ratio predisposes the CKD patients to impaired cardiac oxygen supply versus hypertensive patients and nonmedicated controls.