Determinants of arterial compliance in patients treated by hemodialysis

Background: Cardiovascular disease is the principal cause of morbidity and mortality among hemodialysis patients. Several studies have demonstrated th e importance of a reduction in arterial compliance in the development of ca rdiovascular complications, reflecting the interaction of functional and st ructural alterations of the peripheral arterial system and left ventricle. The aim of the present study was to demonstrate that arterial compliance, e valuated by automated recording of the QKd interval, was lower in hemodialy sis patients than in normal subjects. A secondary objective of the study wa s to assess the influence of several factors, including calcium-phosphorus parameters. on decreased arterial compliance in these patients. Patients an d methods: Arterial compliance was evaluated in 24 chronic hemodialysis pat ients who had normal (n = 12) or high blood pressure (n = 12), using a meth od of measuring systolic wave velocity by automated recording of the QKd in terval. This interval corresponds to the time (in ms) between the onset of the electrocardiogram QRS complex (Q) and the Korotkoff (K) sound at diasto lic pressure (d) heard over the brachial artery during blood pressure measu rement. The analysis was performed in comparison with reference values obta ined in a population with normal renal function. The other parameters deter mined were: age, duration of chronic renal failure, duration of hemodialysi s therapy, left ventricular mass, vascular calcification score. serum total and ionized calcium, phosphorus, parathyroid hormone, calcidiol, calcitrio l, and blood concentration of hemoglobin. Results: The arterial stiffness o f all the patients was increased significantly (p < 0.001) compared to refe rence values obtained from subjects without renal failure, the average age, height, and blood pressure of whom were similar to those of the patients. Multivariate analysis demonstrated a positive relationship among the QKd in terval, serum total calcium, and the duration of hemodialysis. This suggest ed that arterial wall elastic properties were dependent not only on hyperte nsion and constraints of pressure, but that they were also influenced by ca lcium and phosphorus metabolism and the duration of renal substitution ther apy. Conclusions: Arterial compliance, evaluated by the ambulatory method o f QKd measurement, is reduced in chronic hemodialysis patients, and is inve rsely correlated with serum calcium concentration and dependent on the prev ious duration of hemodialysis therapy.