Preliminary study on the intradialytic blood pressure variability and influencing factors

Objective To understand the blood pressure variability (BPV) and the influencing factors through ambulatory blood pressure monitoring during hemodialysis (HD) in the end-stage renal disease (ESRD) patients. Method Eighty-one ESRD patients on maintenancing HD for more than three months were enrolled into the study. The patients were with properly dry body weight. The blood pressure was monitored using dynamic blood pressure monitor around the HD.BPV was estimated with the coefficient of variation (CV) and standard deviation (SD) of the systolic blood pressure (SBP-CV, SBP-SD). Patients were divided into two groups according to the mean of SBP-CV: high SBPV group and low SBPV group. The possible influencing factors such as age, dialysis duration, ultrafiltration volume, ultrafiltration/body weight, therapy of antihypertensive, electrolyte, nutrition state, metabolic bone disease indexes, inflammatory state and serum lipid state were analyzed and compared between the two groups. And multivariate stepwise regression analysis was made between the SBP-CV, SBP-SD and the above observational parameters. Results The average SBP-CV of the 81 patients was (8.12±3.16)%, SBP-SD was (11.22±4.55) mm Hg. The proportion of hypertention and hypotention in high SBPV(SBP-CV≥8.12%) group (20.0%, 25.7%) was higher than that in the low SBPV(SBP-CV＜8.12%) group (8.7%, 6.5%)(P＝0.009). Serum high-sensitivity c-reactive protein (hs-CRP) and alkaline phosphatase (ALP) were higher in high SBPV group than that in the low SBPV group[(7.19±5.95) mg/L vs (3.35±2.78) mg/L, P＝0.001 and (180.31±96.32) U/L vs (98.00±41.19) U/L, P＝0.049]. Serum creatinine and potassium were higher in the low SBPV group than that in the high SBPV group [(1015.83±276.20) μmol/L vs (893.63±216.61) μmol/L, P＝0.034 and (5.27±0.78) mmol/L vs (4.80±0.23) mmol/L, P＝0.005]. SBP-SD was positively correlated with hs-CRP (β＝0.499, P＜0.01), SBP-CV was positively correlated with hs-CRP and dialysis vintage (β＝0.464 and 0.211, P＜0.01 and P＜0.05) by the multivariate stepwise regression analysis. Conclusions The SBP-CV during HD is 8.12% in ESRD patients. Hypertention and hypotention are more often in the higher SBPV patients. SBPV is closely related to the serum hs-CRP.