Increasing Dialysis Sodium Removal on Arterial Stiffness and Left Ventricular Hypertrophy in Hemodialysis Patients.

OBJECTIVE: The aim of the present study was to examine the effects of a mild increase in dialysis sodium removal on cardiovascular system in hypertensive hemodialysis (HD) patients. METHODS: Sixty four HD patients with pre-HD plasma sodium level higher than 138mmol/l, were randomly assigned into 2 groups. The dialysate sodium was reduced from 138mmol/l to 136mmol/l in the intervention group, while remained at 138mmol/l in the control group. During the study course, home systolic blood pressure (BP) target of 140mmHg was used in all patients, and bioimpedance measurements to guide ultrafiltration were performed monthly. 44-hour ambulatory BP, aortic pulse wave velocity (PWV), left ventricular mass index (LVMI), pre-HD plasma sodium concentration, interdialytic weight gain, and dietary sodium intake, were measured. RESULTS: Better BP control was achieved by 2 groups, with no significant differences. However, less annual averages of antihypertensives were used in the intervention group. The PWV values significantly decreased from 11.8±2.4 to 10.9±2.6m/s in the intervention group (P<0.001), and from 11.6±2.5 to 11.1±2.2m/s in the control group (P=0.012). LVMI regressed from 151±19 to 139±16 g/m2 (P<0.001) in the intervention group only. In addition, values for interdialytic weight gain and pre-HD plasma sodium decreased in the intervention group only. There were no significant differences in annual averages of dietary sodium intake and the frequency of adverse events between the 2 groups. CONCLUSIONS: Increasing dialysis sodium removal was associated with improvements in arterial stiffness, left ventricular hypertrophy, and better BP control in hypertensive HD patients.

Is the dialysate calcium concentration of 1.75 mmol/L suitable for Chinese patients on maintenance hemodialysis?

We studied the effects of increasing the dialysate calcium concentration (DCa) to 1.75 mmol/L on controlling chronic kidney disease-mineral and bone disorder in Chinese patients on maintenance hemodialysis (MHD). We reviewed the data of MHD patients in one center (cohort 1) during prior 10 years and analyzed the risk factors of mortality and transference calcification (TC) in120 MHD patients surviving in 2003 (cohort 2). A multicenter, prospective, parallel-group, controlled trial (cohort 3) was also conducted from January 2011 to December 2012. The DCa at one center was increased from 1.5 to 1.75 mmol/L but was not changed at the other two centers. The clinical outcomes, biochemical parameters, medicine treatments, and TC markers [aortic arch calcification score (AoACS)] were compared between groups. In cohort 1, the annual mean serum iPTH increased significantly over 10 years. In cohort 1, 72 patients survived for 10 years, whose doses of calcium salts and active vitamin D3 and AoACs increased progressively. In cohort 2, the main cause of death was cardiocerebrovascular disease (CCVD) (n = 18, 48.6 %). Male sex and lower serum calcium concentrations were independent risk factors for CCVD mortality. In cohort 3, serum phosphorus, iPTH, and 25(OH)D decreased and serum calcium increased significantly; also, the doses of calcium and vitamin D3 decreased from 2011 to 2012 in the DCa 1.75 group. There were no significant differences in clinical outcomes either between groups or between the two calendar years. Our results indicate that increasing DCa to 1.75 mmol/L can decrease the elevated levels of serum iPTH and phosphorus, reduce the doses of calcium and vitamin D3, and be safe for short periods of time.

Impact of dry weight determined by calf bioimpedance ratio on carotid stiffness and left ventricular hypertrophy in hemodialysis patients.

Our previous study has shown that modification of bioimpedance technique by the measurement of bioimpedance ratio in the calf (calf-BR) was a simple and practical method in assessing fluid status in hemodialysis patients. However, the consequences of periodical dry weight (DW) adjustment under the guidance of calf-BR on target organ damage have not been investigated. One hundred fifteen hemodialysis patients were enrolled in this pilot trial. Patients were divided into bioimpedance group and control group according to their dialysis schedule. In the bioimpedance group, DW was routinely adjusted under the guidance of calf-BR every 3 months. In the control group, the assessment of DW remained a clinical judgment. Carotid stiffness, left ventricular mass index (LVMI), and calf-BR were measured at baseline and at the 12th month in both groups. Home blood pressure (BP) was monitored monthly. Episodes of dialysis-related adverse events were recorded. No significant differences were observed in parameters between the two groups at baseline. Compared with the control group, the bioimpedance group had significantly lower values in terms of the annual averages of systolic home BP (147.4 ± 15.3 mm Hg vs. 152.6 ± 16.9 mm Hg, P = 0.019), carotid stiffness index ß (10.7 ± 3.3 vs. 12.2 ± 3.1, P = 0.003), LVMI (155.21 ± 15.64 g/m(2) vs. 165.17 ± 16.76 g/m(2) , P < 0.001), and the percentage of individuals with calf-BR over target range (P = 0.040) at month 12, with less annual averages of antihypertensive medications used and lower frequency of intradialytic hypotension, muscle cramps, or clotted angioaccess. Continued DW control achieved by periodical calf-BR measurement improved arterial stiffness and left ventricular hypertrophy with good tolerability in hemodialysis patients.

Effects of increasing diffusive sodium removal on blood pressure control in hemodialysis patients with optimal dry weight.

BACKGROUND: Sodium, apart from volume, may have an independent effect on blood pressure (BP) regulation. METHODS: Sixteen hypertensive hemodialysis patients were enrolled, who have achieved their dry weight assessed by bioimpedance methods, with pre-dialysis plasma sodium levels slightly higher than the facility dialysate sodium concentration 138 mmol/l. After a 1-month period of dialysis with standard dialysate sodium concentration of 138 mmol/l, the patients were followed up for a 4-month period with dialysate sodium set at 136 mmol/l. RESULTS: Along with lowering dialysate sodium, there were significant decreases (-10 mm Hg and -6 mm Hg) in 44-hour ambulatory systolic and diastolic BP at 4 months. Interdialytic weight gain adjusted to the estimated dry weight mildly but significantly decreased (4.81 ± 1.51 vs. 4.36 ± 1.37%, p = 0.047). The post-dialysis volume parameters remained constant throughout the study period. CONCLUSION: In selected hypertensive hemodialysis patients with optimal dry weight, increasing diffusive sodium removal resulted in significant BP decrease. It was probably due to a volume-independent effect.

Calf bioimpedance ratio improves dry weight assessment and blood pressure control in hemodialysis patients.

BACKGROUND: Chronic fluid overload due to overestimation of dry weight (DW) is the major factor in the development of hypertension in hemodialysis (HD) patients. The present study was undertaken to investigate whether bioimpedance ratio in the calf (Calf-BR = impedance at 200 kHz/impedance at 5 kHz) could be a useful hydration marker for estimation of DW and facilitate better control of blood pressure (BP) in HD patients. METHODS: Target range of Calf-BR was derived from 157 healthy Chinese subjects. Post-dialysis Calf-BR was measured in 117 stable, non-edematous HD patients. Those with Calf-BR(s) above target level had their DW(s) gradually reduced under the guidance of Calf-BR. RESULTS: The Calf-BR was normally distributed and increased with age, but was independent of BMI and gender in both healthy subjects and dialysis patients. HD patients with Calf-BR above age-stratified target range had significantly higher home BP, in spite of more antihypertensive treatments (p = 0.058). The patients who reached the target range of Calf-BR by decreasing DW, had their home BP significantly decreased, along with reduction in antihypertensive medications (p = 0.012). CONCLUSION: Recognition and correction of chronic fluid overload based on age-stratified Calf-BR is helpful in hypertension control in Chinese HD patients.

Efficacy of losartan for improving insulin resistance and vascular remodeling in hemodialysis patients.

Insulin resistance and vascular remodeling are prevalent and predict cardiovascular mortality in hemodialysis patients. Angiotensin II (Ang II) may be involved in both pathogenesis. In the present study, we investigated the effects of the Ang II receptor blocker losartan on insulin resistance, arterial stiffness, and carotid artery structure in hemodialysis patients. Seventy-two hemodialysis patients were randomly assigned to receive either losartan 50 mg qd (n = 36) or ß-blocker bisoprolol 5 mg qd (n = 36). At the start and at month 12, ambulatory blood pressure (BP) monitoring, aortic pulse wave velocity (PWV) measurements, and carotid artery ultrasound were performed, and homeostasis model assessment index of insulin resistance (HOMA-IR) was determined. During the study period, bioimpedance method was used to evaluate volume status every 3 months. Home-monitored BPs were measured at least monthly. Ambulatory BP decreased significantly and similarly by either losartan or bisoprolol. Decreases in PWVs in losartan group at the end of month 12 were significantly greater than changes in PWV in bisoprolol group (0.9 ± 0.3 vs. 0.4 ± 0.5 m/s, P = 0.021). Common carotid artery intima-media cross-sectional area decreased significantly only in patients treated with losartan (20.3 ± 4.9 vs. 19.1 ± 5.1 mm(2) , P = 0.001), and HOMA-IR was also reduced in losartan group only (1.9 ± 1.0 vs. 1.7 ± 0.8, P = 0.003). Multiple regression analysis showed significant correlations between changes in PWV and changes in HOMA-IR. With comparable BP-lowering efficacy, losartan achieved better improvement in insulin sensitivity, arterial stiffness, and carotid artery hypertrophy in hemodialysis patients. The regression of arterial stiffness may be in part through attenuation in insulin resistance.

Comparison of ultrasound echo-tracking technology and pulse wave velocity for measuring carotid elasticity among hemodialysis patients.

This study aims to investigate the correlation between carotid elasticity in hemodialysis patients as evaluated by ultrasound echo-tracking technology and aortic pulse wave velocity. A total of 103 patients with end-stage renal disease who underwent stable hemodialysis were enrolled. An ultrasonic echo-tracking method was used to evaluate the elastic modulus and the stiffness index (ß), which were compared with pulse wave velocity (PWV). Blood glucose, blood lipids, and serum creatinine were also tested. These indices were analyzed to determine the independent factor for arterial elasticity. The carotid elastic modulus and ß were in good correlation with PWV among hemodialysis patients (P = 0.000). Diabetes and age are independent risk factors for arterial elasticity among hemodialysis patients. Ultrasound echo-tracking technology is a sensitive and accurate method for evaluating arterial elasticity and is a good alternative to traditional PWV.

Impact of sodium and ultrafiltration profiling on haemodialysis-related hypotension.

BACKGROUND: Symptomatic hypotension is the most frequent complication in patients receiving haemodialysis (HD). Previous studies have reported that the use of modulating dialysate sodium concentration or ultrafiltration (UF) rates, or the combination use of sodium profile and UF profile may better preserve blood volume and reduce the incidence of hypotensive episodes. The aim of this study was to evaluate the effects of sodium balance-neutral sodium profile and UF profile and their combination on preservation of blood volume, cardiac function and occurrence of hypotensive episodes. METHODS: Using Fresenius MC 4008S, eight stable HD patients underwent four treatments: (1) control, constant dialysate sodium concentration of 138 mmol/l with constant UF; (2) sodium profile, a linearly decreasing dialysate sodium concentration (148-131 mmol/l) with constant UF; (3) UF profile, a linearly decreasing UF rate with dialysate sodium concentration of 138 mmol/l; (4) sodium+UF profile, combination of sodium and UF profile. Each treatment was applied in 10 dialysis sessions. Relative blood volume (RBV), mean blood pressure (MBP), heart rate (HR), interior vena cava diameter (IVCD), stroke volume (SV), cardiac output (CO), plasma sodium concentration and the frequency of symptomatic hypotension were monitored. RESULTS: There were no significant differences in the IVCD, MBP, SV, CO and body weight before dialysis between the three profiles and the control. The total plasma protein, haemoglobin, and intradialytic sodium mass removal showed similar results. Compared with the control, better preservation of RBV and MBP at 4 and 5 h and a higher stability in SV variation, but larger UF volume were achieved during sodium+UF profile (P<0.05, respectively), the incidence of intradialytic hypotension was significantly reduced (P<0.05). CONCLUSIONS: With the similar intradialytic sodium removal, during sodium balance-neutral linearly decreasing sodium profile combined with linearly decreasing UF profile, greater intradialytic stability of the blood volume, blood pressure and cardiac function could be obtained, and hypotensive episodes were significantly reduced.