| Objective: Cardiovascular disease(CVD) is the main complication and cause of death in patients with maintenance hemodialysis(MHD). Hypertension is one of the common complications in patients with MHD, and it can increase the morbidity and mortality of CVD. 24-hour ambulatory blood pressure monitor can reflect the time point, characteristics and circadian rhythm of blood pressure conveniently and truly, and then it has an important clinical value to predict the occurrence of CVD, target organ damage and all-cause mortality in patients with MHD. The purpose of this study is aimed to observe the characteristics and circadian rhythm of blood pressure during dialysis day and inter-dialysis, and explore the influencing factors, then control blood pressure and provide theoretical basis for avoiding CVD.Methods:1 object and date: We enrolled 41 MHD patients into the study, who is conformed to the condition in the third hospital of hebei medical university. 24-hour ambulatory blood pressure monitor was used to monitor the blood pressure both dialysis day and inter-dialysis(the day after dialysis), in order to get parameters, including 24-hour systolic blood pressure, 24-hour diastolic blood pressure, decline in nocturnal systolic and diastolic blood pressure and so on. All patients were applied BCM(Body Composition Monitor) for monitoring volume status before hemodialysis, in order to get TBW, ECW, ICW, ECW/ICW, ECW/TBW, OH and other volume load index. General clinical data, complications, dialysis solutions, antihypertensive drugs and laboratory parameters before or after a month were recorded.2 Group: Two groups were identified with their ambulatory blood pressure: the blood pressure controlled group and blood pressure uncontrolled group. Three groups were identified with range of decline rate of nocturnal systolic blood pressure: dipper group, non-dipper group, anti-dipper group. Patients’ general statistical data, laboratory parameters and volume load index of the two groups were compared, then multivariate stepwise regression was performed respectively between the 24-hour systolic blood pressure, 24-hour diastolic blood pressure, decline in nocturnal systolic blood pressure, decline in nocturnal diastolic blood pressure and above observations indicators.3 Statistical analyses: Continuous data were expressed as mean±standard deviation. Between the two groups, if accorded with normal distribution, using t test, and if didn’t conform to the normal distribution, and then using Mann Wilcoxon U test. Among groups, if accorded with normal distribution and met the homogeneity of variance, using One-Way ANOVA, then the two groups were compared by using LSD. If didn’t conform to the normal distribution or meet the homogeneity of variance, using Kruskal- Wallis H test, each group were no longer pairwise comparison. Categorical data were expressed as percentage of total. Chi-square test was used between groups. In order to analysis the influence factors, multiple stepwise regressions was used. All of the analyses were performed using SPSS software 19.0 and P<0.05 was considered indicative of statistically significant differences.Results:1 During dialysis day the blood pressure controlled group included 9 patients(22.0%), and blood pressure uncontrolled group included 32 patients(78.0%). During inter-dialysis the blood pressure controlled group included 5 patients(12.2%), and blood pressure uncontrolled group included 36 patients(87.8%). By comparing the following index between inter-dialysis and dialysis day found that, 24-hour systolic blood pressure, 24-hour diastolic blood pressure, daytime systolic blood pressure, night systolic blood pressure, night diastolic blood pressure were higher during the inter-dialysis. On the contrary, the daytime diastolic blood pressure, decline in nocturnal systolic blood pressure, decline in nocturnal diastolic blood pressure were lower. The rate of dippers and non-dippers were lower during the inter-dialysis, and rate of anti-dipper were higher. But no significant difference were found(P>0.05).2 Inter-dialysis: 1) The lever of parathyroid hormone in blood pressure uncontrolled group was higher than the controlled group(242.36±20.68pg/ml vs 129.18±26.26pg/ml, P=0.038), and the gender composition ratio, age, duration of dialysis, IDWG, diabetes mellitus, EPO dosage, hemoglobin, serum albumin, pre-dialysis serum creatinine, pre-dialysis serum urea, serum calcium, serum phosphorus, dialysis adequacy(Kt/v, URR) and volume load index, including OH, ECW%, ICW%, ECW/ICW, ECW/TBW were not significantly differed between the blood pressure controlled group and blood pressure uncontrolled group(P> 0.05). 2) The dipper group included 3 patients(7.3%), the non-dipper group included 18 patients(43.9%), and the anti-dipper group included 20 patients(48.8%). Nevertheless, the dipper group due to fewer cases was not included in the statistics. The age of patients in non-dipper group were lower than patients in anti-dipper group(54.00±3.44 vs 62.85±2.71, P=0.049), but ICW% were higher(28.53±5.32 vs 25.23±4.04, P=0.019). The other indicators were not significantly differed between the two groups(P > 0.05). 3) Multivariate stepwise regression analyses were respectively applied 24-hour systolic blood pressure, 24-hour diastolic blood pressure, decline in nocturnal systolic blood pressure, decline in nocturnal diastolic blood pressure as the dependent variable, and the above indicators as independent variables. The results showed that 24-hour systolic blood pressure was positively correlated with ECW/ICW, pre-dialysis serum creatinine(β= 55.575, 0.021, P= 0.013, 0.042), and it was negatively correlation with hemoglobin(β=-0.280, P=0.031); 24-hour diastolic blood pressure was negatively correlated with age(β=-0.637, P<0.001); decline in nocturnal systolic blood pressure was negatively correlated with age, OH, serum phosphorus(β=-0.214,-3.328,-8.092, P=0.008, 0.003, 0.003); decline in nocturnal diastolic blood pressure was positively correlated with ICW%(β= 1.216, P<0.001), and it was negatively correlated with OH, pre-dialysis serum urea(β =-4.608,-0.534, P<0.001, P =0.044).3 Dialysis day: 1) The lever of parathyroid hormone in blood pressure uncontrolled group was higher than the controlled group(134.08±19.19 vs 255.13±21.98, P=0.005); and the other indicators were not significantly differed between the two groups(P>0.05). 2) The dipper group included 6 patients(14.6%), the non-dipper group included 23 patients(56.1%), and the anti-dipper group included 23 patients(56.1%). The lever of parathyroid hormone in the dipper group was lower than the other two groups(120.28±15.25pg/ml vs 238.75±28.31pg/ml vs 263.16±28.76pg/ml, P=0.018), and the other indicators were not significantly differed between each other(P>0.05). 3)Multivariate stepwise regression analysis were respectively applied, 24-hour systolic blood pressure, 24-hour diastolic blood pressure, decline in nocturnal systolic blood pressure, decline in nocturnal diastolic blood pressure as the dependent variable, and the above indicators as independent variables. The results showed that 24-hour systolic blood pressure was positively correlated with ECW/ICW(β=72.282, P=0.007); 24-hour diastolic blood pressure was negatively correlated with age(β=-0.631, P<0.001); decline in nocturnal systolic blood pressure was positively correlated with hemoglobin(β=0.183, P=0.024); decline in nocturnal diastolic blood pressure was positively correlated with hemoglobin, serum albumin(β=1.358, 0.266, P=0.001, 0.003), and it was negatively correlated with serum calcium( β=-26.822, P=0.002).Conclusions:1 MHD patients have a prevalent hypertension and circadian rhythm abnormalities, and the proportion of the decline in nocturnal blood pressure and are decreased. Blood pressure rhythm is mainly characterized by non-dipper, even anti-dipper.2 The blood pressure levels and circadian rhythm in both inter-dialysis and dialysis day are influenced by overhydration, parathyroid hormone, age, and so on. The heavier the capacity, and the higher parathyroid hormone levels, then the higher blood pressure, the lower rate of nocturnal blood pressure decline rate, the higher proportion of non-dipper and the proportion of anti-dipper rhythm. MHD patients with strictly control weight gain, fully clear the size of molecules, appropriately adjustments step-down scheme at the same time, can reduce blood pressure and proportion of non-dipper and the proportion of anti-dipper rhythm, then reduce CVD.3 MHD patients during inter-dialysis have a higher blood pressure, but lower proportion of decline in nocturnal blood pressure and dipper rhythm. |
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