[Arterial blood pressure changes, circadian rhythm and arterial elasticity in hemodialysed patients]

An increased blood pressure variability (BVP) and a loss of nocturnal decline in BP could enhance cardiovascular disease. Peripheral resistances and arterial compliance determine systolic BP. BVP could depend on arterial stiffness. We tested this hypothesis in patients with end-stage renal disease (ERSD) who have arterial elasticity impairment. Twenty one ESRD patients (49.9 +/- 16.7 years) 12 mean and 9 women, undergoing maintenance hemodialysis were studied; 19 had treated hypertension. Ambulatory (ABP) monitoring was performed in all patients: BP was measured every 15 minutes in day-time and every 30 minutes at night. Systolic diurnal variation coefficient was calculated as the ratio between standard deviation and the mean of systolic diurnal BP. Nycthemeral BP pattern was evaluated as the ratio between mean diurnal and nocturnal systolic BP (N/D). Pulse wave velocity (PVW), an index of arterial stiffness, was determined between carotid and femoral sites (11.6 +/- 4.22 m/s). These investigations were performed after the midweek dialysis session. We found a positive correlation between PVW and systolic diurnal BPV (stepwise regression F = 12.9, p < 0.01). This correlation was independent of hypertension, antihypertensive treatment, duration of hemodialysis, and erythropoientin. We also found a positive correlation between N/D and PWV (stepwise regression: F = 8.9 p < 0.05). Our study shows that arterial distensibility links BPV and N/D. It is suggested that an arterial distensibility impairment could enhance BPV and modify nycthemeral BP pattern.