| BackgroundBlood pressure(BP) is one of the most important risk factor to effect the prognosis of patients on dialysis,but most of the researches focused on the level of BP. In general population more and more studies have proven that variability in blood pressure was an independent predictor for cardiovascular disease and mortality. But the prognostic value of it was less investigated in dialysis patients.The relationship between long-term BP variability and prognosis in peritoneal dialysis patients hadn’t been reported. Factors related with BP variability hadn’t been fully investigated.Volume reduction accompanied with dialysis was a prominent characteristic of patients on maintenance hemodialysis.It was known that volume change could effect short-term BP variability,but the effect on long-term variability is still unknown.Purpose1. To identify the association between the long-term variability in blood pressure and mortality in hemodialysis(HD) and peritoneal dialysis(PD) patients, to analyze the effect of volume change on long-term blood pressure variability.2.To observe the relationship of short-term volume change with the changes of peripheral and central blood pressure, and the index of arterial elasticity.To analyze the correlated factors of arterial elasticity and reflected pulse wave.3.To observe the change of renin-angiotensin-system(RAS) after dialysis,to identify correlated factors of the response of RAS for clearance of water and sodium, and relationship between RAS and volume status.Method1. The subjects were99hemodialysis patients and69peritoneal dialysis patients in our dialysis center. Complete records of99hemodialysis patients in2006which were14,703times hemodialysis sessions were reviewed,including predialytic and postdialytic BP,heart rate and body weight. The outpatients records of69peritoneal patients were also reviewed,consecutive6blood pressure were collected. Coefficient of variation(CV=SD/MEAN) in blood pressure was used as an indicator of blood pressure variability.Baseline clinical data and lab tests were also reviewed. Patients were followed up for83and59months for hemodialysis patients and peritoneal dialysis patients,respectively.Death was the primary end point.Cox regression analysis was used to identify the independent predictors for mortality(SPSS18.0for windows).2.54patients on maintenance hemodialysis were included. Predialytic and postdialytic central arterial pressure waveform parameters were estimated by radial artery applanation tonometry, using a Sphygmocor device(ArtCor). Omron-Colin was used to measure brachial-ankle pulse wave velocity(baPWV).Blood was drawn to measure plasma renin activity(PRA),angiotensin Ⅱ (AngⅡ)and aldosterone(ALD).Correlation analysis and multiple regression analysis were used to identify the relationship of volume change with the change of blood pressure,renin-angiotensin system(RAS) and arterial elasticity(SPSS18.0for windows).Results1.Blood pressure and prognosis in hemodialysis and peritoneal dialysis patients.During follow up,41(41.4%) of hemodialysis patients and31(44.9%) peritoneal dialysis patients died.Cardiocerebral event was the most common cause of death in HD and PD patients.Vascular event was the leading cause in HD patients (80.0%),while heart failure in PD patients(52.9%). Predialytic SBP(preSBP)<120mmHg and Office SBP>153mmHg were independent predictors for all-cause and cardiovascular mortality for HD and PD patients..respectively.2.Predialytic variability of BP and heart rate were independent risk factors for mortality in hemodialysis patients.Predialytic variability of systolic BP(SBP) and diastolic BP(DBP) were all independent risk factors for all-cause mortality.The hazard ratio for each index were coeffient of variability for SBP (SBPCV)(HR1.200,95%CI1.046-1.378,P=0.010), coeffient of variability for DBP(DBPCV)(HR1.097,95%CI1.011-1.184, P=0.018) and the slope of change of SBP(HR6.826,95%CI2.239-20.810, P=0.001),respectively. DBPCV (HR1.147,95%CI1.053-1.250, P=0.002) was also the independent risk factor for cardiovascular mortality. Predialytic heart rate variability was an independent risk factors for all-cause mortality in HD patients. Visit to Visit variability(VVV) of BP wasn’t a predictor for mortality in PD patients.Multiple linear regression analysis identified the variability of weight lose during dialysis was positively correlated with the variability of preSBP(β=3.291, P=0.008),while serum albumin was negatively(β=-0.218, P=0.010).DBPCV was negatively correlated with serum albumin (β=-0.413, P=0.031)3.Predialytic BP was correlated with volume change in hemodialysis patients and the index of arterial stiffness changed after dialysis. Interdialysis weight gain(IDWG) was positively correlated with peripheral and central SBP. No changes had been identified between predialytic and postdialytic peripheral or central blood pressure. Postdialytic Aix was lower than predialysis,but postdialytic baPWV was higher.Non of the changes of Aix and baPWV were related with volume change.Intradialytic hypertension and hypotension were correlated with arterial elasticity and reflected pressure wave.54patients were divided into2groups as intradialysis hypertension group and non-hypertension group,according to whether or not an increase in SBP of at least10mmHg in the third hour. The former group was found to have higher postdialytic Augmentation index (Aix)(31.6±25.36%vs21.67±11.51%, P=0.000).Aix increased in the former group after dialysis,but decreased in the latter group. baPWV increased in both groups after dialysis,but the hypertension group had a greater increase.According to whether or not the lowest SBP during dialysis below90mmHg or a drop in MAP at least30mmHg,patients were divided into intradilysis hypotension(IDH) group and the non-hypotension group. Patients in IDH were found to have lower postdialytic Aix(17.21±10.19%vs30.11±8.18%,P=0.000).4.RAS was activated in part of hemodialysis patients after dialysis.The increase of RAS were correlated with the decrease of volume and sodium.Accompanied with volume and sodium decrease in dialysis,there were47.4%patients had increased PRA,52.6%patients had increased AngⅡ,and30.6%patients and increased ALD.The change of PRA and AngⅡ had positive relationship with the change of volume and sodium in these patients.Nearly half of hemodialysis patients had no response as to volume decrease.Compared with non-hypertension patients, postdialytic AngⅡ was lower in the intradialytic hypertension patients(92.53±39.09pg/ml vs67.85±13.28pg/ml, P=0.006).Conclusion1. Variability of predialytic SBP and heart rate were independent risk factors for all-cause and cardiovascular mortality in hemodialysis patients. The BP variability was correlated with the variability of volume change and serum albumin.Visit-to-Visit variability of BP was not a predictor for mortality in PD patients.2.Short-term volume change determined peripheral and central BP in hemodialysis patients. RAS was activated in part of hemodialysis patients after dialysis.3.Arterial stiffness and resistance played a role in the development of intradialysis hypertension and hypotension, but RAS didn’t seem to be the cause of the change of arterial stiffness during hemodialysis. |
PDF Full Text Request