Acute vs chronic volume overload on arterial stiffness in haemodialysis patients

Abstract

Volume overload is a cardinal feature of end-stage renal disease (ESRD) patients. Acute volume overload, as represented by interdialytic weight gain, is associated with increased aortic pulse wave velocity (aPWV) and independently related to total mortality in haemodialysis patients.1, 2 Based on the Laplace's law, volume expansion increases arterial stiffness (or reduces arterial compliance) by increasing arterial distension. Therefore, it would appear intriguing that acute volume reduction by ultrafiltration does not always acutely improve arterial stiffness.3, 4, 5, 6, 7 Dialysis with a 'low-calcium' dialysate (1.50 mmol/l) did not change aPWV, while dialysis with a 'high-calcium' dialysate (1.75 mmol/l) even induced a significant increase in aPWV.6 Haemodialysis with polysulphone but not polyamide membranes may acutely increase aPWV, probably due to membrane bioincompatibility.7 In contrast, by combining carotid pulse contour analysis with aortic outflow measurements, Le et al8 was able to demonstrate that acute volume removal improved aortic compliance in haemodialysis patients who had already attained dry weight and had normal systolic and diastolic function. While aPWV was not different after haemodialysis in the study, the results suggested that the increase in aortic stiffness in haemodialysis patients is partly caused by a reversible reduction of aortic compliance due to volume expansion.8