Determinants of arterial compliance in patients treated by hemodialysis

Cardiovascular disease is the principal cause of morbidity and mortality among hemodialysis patients. Several studies have demonstrated the importance of a reduction in arterial compliance in the development of cardiovascular complications, reflecting the interaction of functional and structural alterations of the peripheral arterial system and left ventricle. The aim of the present study was to demonstrate that arterial compliance, evaluated by automated recording of the QKd interval, was lower in hemodialysis patients than in normal subjects. A secondary objective of the study was to assess the influence of several factors, including calcium-phosphorus parameters, on decreased arterial compliance in these patients.

Arterial compliance was evaluated in 24 chronic hemodialysis patients who had normal (n = 12) or high blood pressure (n = 12), using a method of measuring systolic wave velocity by automated recording of the QKd interval. This interval corresponds to the time (in ms) between the onset of the electrocardiogram QRS complex (Q) and the Korotkoff (K) sound at diastolic pressure (d) heard over the brachial artery during blood pressure measurement. The analysis was performed in comparison with reference values obtained in a population with normal renal function. The other parameters determined were: age, duration of chronic renal failure, duration of hemodialysis therapy, left ventricular mass, vascular calcification score, serum total and ionized calcium, phosphorus, parathyroid hormone, calcidiol, calcitriol, and blood concentration of hemoglobin.

The arterial stiffness of all the patients was increased significantly (p < 0.001) compared to reference 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 interval, serum total calcium, and the duration of hemodialysis. This suggested that arterial wall elastic properties were dependent not only on hypertension and constraints of pressure, but that they were also influenced by calcium and phosphorus metabolism and the duration of renal substitution therapy.

Arterial compliance, evaluated by the ambulatory method of QKd measurement, is reduced in chronic hemodialysis patients, and is inversely correlated with serum calcium concentration and dependent on the previous duration of hemodialysis therapy.