Hypervolemia is associated with increased mortality among hemodialysis patients

Target weight achievement and ultrafiltration rate thresholds: potential patient implications

BACKGROUND

Higher ultrafiltration (UF) rates and extracellular hypo- and hypervolemia are associated with adverse outcomes among maintenance hemodialysis patients. The Centers for Medicare and Medicaid Services recently considered UF rate and target weight achievement measures for ESRD Quality Incentive Program inclusion. The dual measures were intended to promote balance between too aggressive and too conservative fluid removal. The National Quality Forum endorsed the UF rate measure but not the target weight measure. We examined the proposed target weight measure and quantified weight gains if UF rate thresholds were applied without treatment time (TT) extension or interdialytic weight gain (IDWG) reduction.

METHODS

Data were taken from the 2012 database of a large dialysis organization. Analyses considered 152,196 United States hemodialysis patients. We described monthly patient and dialysis facility target weight achievement patterns and examined differences in patient characteristics across target weight achievement status and differences in facilities across target weight measure scores. We computed the cumulative, theoretical 1-month fluid-related weight gain that would occur if UF rates were capped at 13 mL/h/kg without concurrent TT extension or IDWG reduction.

RESULTS

Target weight achievement patterns were stable over the year. Patients who did not achieve target weight (post-dialysis weight ≥ 1 kg above or below target weight) tended to be younger, black and dialyze via catheter, and had shorter dialysis vintage, greater body weight, higher UF rate and more missed treatments compared with patients who achieved target weight. Facilities had, on average, 27.1 ± 9.7% of patients with average post-dialysis weight ≥ 1 kg above or below the prescribed target weight. In adjusted analyses, facilities located in the midwest and south and facilities with higher proportions of black and Hispanic patients and higher proportions of patients with shorter TTs were more likely to have unfavorable facility target weight measure scores. Without TT extension or IDWG reduction, UF rate threshold (13 mL/h/kg) implementation led to an average theoretical 1-month, fluid-related weight gain of 1.4 ± 3.0 kg.

CONCLUSIONS

Target weight achievement patterns vary across clinical subgroups. Implementation of a maximum UF rate threshold without adequate attention to extracellular volume status may lead to fluid-related weight gain.

The cardiothoracic ratio and all-cause and cardiovascular disease mortality in patients undergoing maintenance hemodialysis: results of the MBD-5D study

BACKGROUND

The cardiothoracic ratio (CTR) is a non-invasive left ventricular hypertrophy index. However, whether CTR associates with cardiovascular disease (CVD) and mortality in hemodialysis (HD) populations is unclear.

METHODS

Using a Mineral and Bone disorder Outcomes Study for Japanese CKD Stage 5D Patients (MBD-5D Study) subcohort, 2266 prevalent HD patients (age 62.8 years, female 38.0%, HD duration 9.4 years) with secondary hyperparathyroidism (SHPT) whose baseline CTR had been recorded were selected. We evaluated associations between CTR and all-cause death, CVD death, or composite events in HD patients.

RESULTS

CTR was associated significantly with various background and laboratory characteristics. All-cause death, CVD-related death, and composite events increased across the CTR quartiles (Q). Adjusted hazard risk (HR) for all-cause death was 1.4 (95% confidential interval, 0.9-2.1) in Q2, 1.9 (1.3-2.9) in Q3, and 2.6 (1.7-4.0) in Q4, respectively (Q1 as a reference). The corresponding adjusted HR for CVD-related death was 1.8 (0.8-4.2), 3.1 (1.4-6.8), and 3.5 (1.6-7.9), and that for composite outcome was 1.2 (1.0-1.6), 1.7 (1.3-2.2), and 1.8 (1.5-2.3), respectively. Exploratory analysis revealed that there were relationships between CTR and age, sex, body mass index, comorbidity of CVD, dialysis duration and intact parathyroid hormone, phosphorus, hemoglobin, and usage of phosphate binder [corrected].

CONCLUSION

CTR correlated with all-cause death, CVD death, and composite events in HD patients with SHPT.

Brain Natriuretic Peptide Is a Marker of Fluid Overload in Incident Hemodialysis Patients

BACKGROUND/AIMS

Brain natriuretic peptide (BNP) is secreted by cardiomyocytes under stretch condition. High blood levels are associated with decreased patient survival in heart failure patients and in hemodialysis (HD) patients. We report the monthly BNP change in the first months of HD therapy in incident patients and its relationship with fluid removal and cardiac history (CH).

METHODS

All patients starting HD therapy in our unit from May 2008 to December 2012 were retrospectively analyzed. Every month (M1 to M6), BNP was assessed before a midweek dialysis session. CH, monthly pre- and postdialysis blood pressure, and postdialysis body weight were collected.

RESULTS

A total of 236 patients were included in the analysis. The median BNP at HD start was 593 (175-1,433) pg/mL, with a significant difference between CH- and CH+ patients (291 vs. 731 pg/mL, p < 0.0001). Mortality was significantly higher in patients in the higher BNP tertile. BNP decreased significantly between M1 and M2 and then plateaued. The BNP change between M1 and M2 and between M1 and M6 was significantly correlated with the initial fluid removal. Applying stepwise multiple regression, the BNP change between M1 and M2 was significantly and independently related to fluid removal. The BNP level at M6 was also related to patient survival.

CONCLUSIONS

We confirm that in incident HD patients, BNP level is related to fluid excess and cardiac status. The BNP decrease in the first months of HD therapy is related to fluid excess correction. BNP appears as an important tool to evaluate hydration status correction after HD onset.

Investigation of optimum N-terminal probrain natriuretic peptide level in patients on maintained hemodialysis

Background: Serum N-terminal probrain natriuretic peptide (NT-proBNP) level is known to be strongly associated with fluid overload, and serves as a guide for fluid management in patients on hemodialysis (HD). This study aimed at investigating the relationship between NT-proBNP level and blood pressure (BP), ultrafiltration/dry weight ratio as well as hemoglobin, and to explore the optimal cutoff point of NT-proBNP level in Chinese patients on HD.

Methods: A total of 306 patients on maintained HD for stage 5 chronic kidney disease (CKD) were included in this prospective study. Their average ultrafiltration/dry weight ratio and BP before dialysis were recorded. The serum NT-proBNP, hemoglobin, serum calcium, and phosphorus were detected. The cutoff value for NT-proBNP level was calculated using receiver operating characteristic (ROC) analysis.

Results: The high NT-proBNP level was associated with high BP and ultrafiltration/dry weight ratio, and low hemoglobin level. The optimal cutoff point of NT-proBNP level for patients on maintained HD was 5666 pg/mL, with a sensitivity of 78.5%, specificity of 43.9%, and area under the curve (AUC) of 0.703 (<0.001).

Conclusions: NT-proBNP level ≤5666 pg/mL was recommended to achieve the target BP, hemoglobin level, and ultrafiltration/dry weight ratio in patients on maintained HD with an ejection fraction (EF) >50%.

Efficacy of a remote web-based lung ultrasound training for nephrologists and cardiologists: a LUST trial sub-project

Within the framework of the LUST trial (LUng water by Ultra-Sound guided Treatment to prevent death and cardiovascular events in high-risk end-stage renal disease patients), the European Renal and Cardiovascular Medicine (EURECA-m) working group of the European Renal Association-European Dialysis Transplant Association established a central core lab aimed at training and certifying nephrologists and cardiologists participating in this trial. All participants were trained by an expert trainer with an entirely web-based programme. Thirty nephrologists and 14 cardiologists successfully completed the training. At the end of training, a set of 47 lung ultrasound (US) videos was provided to trainees who were asked to estimate the number of B-lines in each video. The intraclass correlation coefficient (ICC) for the whole series of 47 videos between each trainee and the expert trainer was high (average 0.81 ± 0.21) and >0.70 in all but five cases. After further training, the five underperforming trainees achieved satisfactory agreement with the expert trainer (average post-retraining ICC 0.74 ± 0.14). The Bland-Altman plot showed virtually no bias (difference between the mean 0.03) and strict 95% limits of agreement lines (-1.52 and 1.45 US B-lines). Only four cases overlapped but did not exceed the same limits. Likewise, the Spearman correlation coefficient applied to the same data series was very high (r = 0.979, P < 0.0001). Nephrologists and cardiologists can be effectively trained to measure lung congestion by an entirely web-based programme. This web-based training programme ensures high-quality standardization of US B-line measurements and represents a simple, costless and effective preparatory step for clinical trials targeting lung congestion.

Impact of residual urine volume decline on the survival of chronic hemodialysis patients in Kinshasa

Background

Despite the multiple benefits of maintaining residual urine volume (RUV) in hemodialysis (HD), there is limited data from Sub-Saharan Africa. The aim of this study was to assess the impact of RUV decline on the survival of HD patients.

Methods

In a retrospective cohort study, 250 consecutive chronic HD patients (mean age 52.5 years; 68.8% male, median HD duration 6 months) from two hospitals in the city of Kinshasa were studied, between January 2007 and July 2013. The primary outcome was lost RUV. Preserved or lost RUV was defined as decline RUV < 25 (median decline) or ≥ 25 ml/day/month, respectively. The second endpoint was survival (time-to death). Survival curves were built using the Kaplan-Meier methods. We used Log-rank test to compare survival curves. Predictors of mortality were assessed by Cox proportional hazards regression models.

Results

The cumulative incidence of patients with RUV decline was 52, 4%. The median (IQR) decline in RUV was 25 (20.8–33.3) ml/day/month in the population studied, 56.7 (43.3–116.7) in patients deceased versus 12.9 (8.3–16.7) in survivor patients (p < 0.001). Overall mortality was 78 per 1000 patient years (17 per 1000 in preserved vs 61 per 1000 lost RUV). Forty six patients (18.4%) died from withdrawal of HD due to financial constraints. The Median survival was 17 months in the whole group while, a significant difference was shown between lost (10 months, n = 119) vs preserved RUV group (30 months, n = 131; p = 0001). Multivariate Cox proportional hazards models showed that, decreased RUV (adjusted HR 5.35, 95% CI [2.73–10.51], p < 0.001), financial status (aHR 2.23, [1.11–4.46], p = 0.024), hypervolemia (a HR 2.00, [1.17–3.40], p = 0.011), lacking ACEI (aHR 2.48, [1.40–4.40], p = 0.002) or beta blocker use (aHR 4.04, [1.42–11.54], p = 0.009), central venous catheter (aHR 6.26, [1.71–22.95], p = 0.006), serum albumin (aHR 0.93, [0.89–0.96], p < 0.001) and hemoglobin (aHR 0.73, [0.63–0.84], p < 0.001) had emerged as the independent predictors of all-cause mortality.

Conclusion

More than half of HD patients in this cohort study experienced fast RUV decline which contributed substantially to increase mortality, highlighting the need for its prevention and management.

Epidemiology, diagnosis and management of hypertension among patients on chronic dialysis

The diagnosis and management of hypertension among patients on chronic dialysis is challenging. Routine peridialytic blood pressure recordings are unable to accurately diagnose hypertension and stratify cardiovascular risk. By contrast, blood pressure recordings taken outside the dialysis setting exhibit clear prognostic associations with survival and might facilitate the diagnosis and long-term management of hypertension. Once accurately diagnosed, management of hypertension in individuals on chronic dialysis should initially involve non-pharmacological strategies to control volume overload. Accordingly, first-line strategies should focus on achieving dry weight, individualizing dialysate sodium concentrations and ensuring dialysis sessions are at least 4 h in duration. If blood pressure remains unresponsive to volume management strategies, pharmacological treatment is required. The choice of appropriate antihypertensive regimen should be individualized taking into account the efficacy, safety, and pharmacokinetic properties of the antihypertensive medications as well as any comorbid conditions and the overall risk profile of the patient. In contrast to their effects in the general hypertensive population, emerging evidence suggests that β-blockers might offer the greatest cardioprotection in hypertensive patients on dialysis. In this Review, we discuss estimates of the epidemiology of hypertension in the dialysis population as well as the challenges in diagnosing and managing hypertension among these patients.

Ultrafiltration Rate Thresholds in Maintenance Hemodialysis: An NKF-KDOQI Controversies Report

High hemodialysis ultrafiltration rate (UFR) is increasingly recognized as an important and modifiable risk factor for mortality among patients receiving maintenance hemodialysis. Recently, the Kidney Care Quality Alliance (KCQA) developed a UFR measure to assess dialysis unit care quality. The UFR measure was defined as UFR≥13mL/kg/h for patients with dialysis session length less than 240 minutes and was endorsed by the National Quality Forum as a quality measure in December 2015. Despite this, implementation of a UFR threshold remains controversial. In this NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) Controversies Report, we discuss the concept of the UFR, which is governed by patients' interdialytic weight gain, body weight, and dialysis treatment time. We also examine the potential benefits and pitfalls of adopting a UFR threshold as a clinical performance measure and outline several aspects of UFR thresholds that require further research.

Controversies and problems of volume control and hypertension in haemodialysis

Extracellular volume overload and hypertension are important contributors to the high risk of cardiovascular mortality in patients undergoing haemodialysis. Hypertension is present in more than 90% of patients at the initiation of haemodialysis and persists in more than two-thirds, despite use of several antihypertensive medications. High blood pressure is a risk factor for the development of left ventricular hypertrophy, heart failure, and mortality, although there are controversies with some study findings showing poor survival with low-but not high-blood pressure. The most frequent cause of hypertension in patients undergoing haemodialysis is volume overload, which is associated with poor cardiovascular outcomes itself independent of blood pressure. Although antihypertensive medications might not be successful to control blood pressure, extracellular volume reduction by persistent ultrafiltration and dietary salt restriction can produce favourable results with good blood pressure control. More frequent or longer haemodialysis can facilitate volume and blood pressure control. However, successful volume and blood pressure control is also possible in patients undergoing conventional haemodialysis.

Impedance ratio: a novel marker and a powerful predictor of mortality in hemodialysis patients

PURPOSE

Impedance ratio (Imp-R) obtained by multifrequency bioimpedance analysis (BIA) has been shown to be associated with volume and nutrition status. In this prospective study, the predictive role of Imp-R for mortality in hemodialysis (HD) patients was investigated.

METHODS

Multifrequency (5-50-100-200 kHz) BIA was applied to 493 prevalent HD patients in March-April 2006. Imp-R was defined as the ratio of 200-5 kHz impedance values. Demographical, clinical and laboratory data at the time of the analysis were recorded. All-cause and cardiovascular (CV) mortality were assessed during 3 years of follow-up.

RESULTS

Mean age was 57.7 ± 13.9 years, HD duration 52.1 ± 42.6 months and prevalence of diabetes 21.7 %. Imp-R was negatively correlated with nutritional markers including albumin, creatinine and hemoglobin levels. In addition, there was a positive correlation between Imp-R and age, ratio of extracellular water to total body water and high-sensitive C-reactive protein. Over a mean follow-up period of 27.9 ± 11.1 months, 93 deaths (52 from CV reasons) were observed. In the multivariate analysis, Imp-R was significantly associated with all-cause and CV mortality after adjustments [HR 1.13, 95 % CI (1.04-1.23); p = 0.004 and HR 1.15, 95 % CI (1.03-1.27); p = 0.01, respectively]. The risk of all-cause mortality was 3.4 times higher in the fourth quartile of Imp-R (>83.5 %) compared to the first Imp-R quartile (<78.8 %) as reference. Cutoff value of Imp-R for all-cause mortality was 82.0 % with a sensitivity of 65.5 % and specificity of 64 %.

CONCLUSION

Impedance ratio measured by multifrequency in standardized conditions BIA is an independent and powerful predictor of both all-cause and CV mortality in hemodialysis patients.

A systematic review on randomized control trials on rennin angiotensin aldosterone system inhibitors role in managing hypertension among hemodialysis patients

Randomized control trials (RCTs) are considered as most rigors way of determining the cause-effect relationship of a treatment and outcome. Activation of rennin angiotensin aldosterone system (RAAS) is an important contributor to hypertension in hemodialysis patients. The prevalence of hypertension in hemodialysis patients varies from 60% to 80% and hypertension management alone with conventional hemodialysis is insufficient. Hence, the current review was aimed to investigate the effect of RAAS inhibitors in managing hypertension among hemodialysis patients in a randomized control trial. Using PUBMED and EMBASE databases, randomized control trial with primary or secondary outcomes related to the effect of RAAS inhibitors on blood pressure among hemodialysis patients were included for analysis. The current review also assessed the quality of reporting of RCT. A total of eight RCT met inclusion criteria for current review. According to modified jaded scale, one (12.5%) study scored four points for quality reporting, whereas two (25%) studies scored one point that was the least score. The mean score for all included studies was 2.25. Six (75%) of the eight RCT included, involved ARB in hypertension management among hemodialysis patients, whereas two (25%) studies involved angiotensin-converting enzyme (ACE) inhibitors. Of the siz RCT involving ARB, two (33.3%) RCT also included ACE inhibitors comparison group. Altogether six (75%) studies report a reduction in blood pressure with the use of RAAS inhibitors compared to control group; however, of the six studies, two (33.3%) reported that the reduction in blood pressure was not significant. Whereas, two (25%) studies reported no reduction in blood pressure compared to the control group. The findings from current review do not indicate a clear pattern for a role of RAAS inhibitors for hypertension control among hemodialysis patients.

Methods and challenges for the practical application of Crit-Line™ monitor utilization in patients on hemodialysis

The Crit-Line™ monitor measures relative changes in intravascular blood volume during hemodialysis. The device is also used to monitor hematocrit and oxygen saturation. Using this device to decrease fluid volume has yielded inconsistent results on outcome measures such as hospitalization rates, erythropoietin utilization, and blood pressure reduction. Through a year-long deployment of the Crit-Line™ monitor, the Renal Research Institute (RRI) has shown that outcomes can be improved even in a busy dialysis clinic with attention to the details of how the device is utilized. In this paper, we are proposing areas of focus and methods that if properly implemented should yield improved clinical outcomes. Strong physician approval and enthusiasm coupled with clinical staff support have been shown to be vital to the success of this device in improving clinical outcomes. Even in this setting, inadequately and improperly trained staff have been identified as almost insurmountable impediments to adequate Crit-Line™ use. Our studies have shown that in facilities where staff turnover is high, procedures must be implemented to engage and train new staff immediately upon their arrival on the dialysis floor. Other issues that may lead to improper use of the Crit-Line™ monitor include incorrect target weight assessments, failure of staff to properly monitor patients during the treatment, and the over dependency of saline administration for cramps.

Effect of personalized nutritional counseling in maintenance hemodialysis patients

Monitoring nutritional parameters is an integral part of hemodialysis (HD) patient treatment program. The purpose of this study was to evaluate the impact of the personalized nutritional counseling (PNC) on calcium-phosphorus metabolism, potassium, albumin, protein intake, interdialytic weight gain (IDWG), body composition parameters and fluid overload in HD patients. This was a multicenter longitudinal intervention study with 6 months of follow-up and 731 patients on maintenance HD from 34 dialysis units in Portugal were enrolled. Biochemical and body composition parameters were measured at baseline, 1, 3 and 6 months after the PNC. Patient's mean age was 64.9 (95% confidence interval [CI]: 63.8-66.0) years and mean HD time was 59.8 (95% CI: 55.3-64.3) months. Regarding data comparison collected before PNC vs. 6 months after, we obtained, respectively, the following results: patients with normalized protein catabolic rate (nPCR) ≥ 1 g/kg/day = 66.5% vs. 73.5% (P = 0.002); potassium > 5.5 mEq/L = 52% vs. 35.8% (P < 0.001); phosphorus between 3.5 and 5.5 mg/dL = 43.2% vs. 52.5% (P < 0.001); calcium/phosphorus (Ca/P) ratio ≤ 50 mg/dL = 73.2 % vs. 81.4% (P < 0.001); albumin ≥ 4.0 g/dL = 54.8% vs. 55% (P = 0.808); presence of relative overhydration = 22.4% vs. 25% (P = 0.283); IDWG > 4.5% = 22.3% vs. 18.2% (P = 0.068). PNC resulted in a significant decrease in the prevalence of hyperkalemia, hypophosphatemia and also showed amelioration in Ca/P ratio, nPCR and an increase in P of hyphosphatemic patients. Our study suggests that dietetic intervention contributes to the improvement of important nutritional parameters in patients receiving hemodialysis treatment.

A year-long quality improvement project on fluid management using blood volume monitoring during hemodialysis

BACKGROUND

Inadequate removal of extracellular volume markedly increases blood pressure and contributes to high morbidity and mortality in hemodialysis patients. Advances in fluid management are needed to improve clinical outcomes. The aim of this quality improvement project was to examine the advantages of using a hematocrit-based, blood volume monitor (Crit-Line * ) for 12 months, as part of a clinic-wide, fluid management program in one dialysis facility.

METHODS

Forty-five individuals were receiving hemodialysis at one facility at project initiation and are included in this analysis. Monthly averaged clinical parameters (dialysis treatment information, blood pressures, blood volume, and laboratory data) were compared from Months 1-12. Analyses were conducted overall and according to the presence/absence of hypertension at Month 1 (Baseline). Antihypertensive medication changes were assessed for patients with hypertension at Month 1.

RESULTS

Average hemodialysis treatment time (+10.6 minutes, p = 0.002), eKt/V (+0.25, p < 0.001) and online clearance (+0.21, p < 0.0001) increased significantly in Month 12 versus Month 1. Average albumin levels and normalized protein catabolic rate increased from Month 1 to 12. Post-dialysis systolic blood pressure (SBP) decreased by Month 12 (p = 0.003). In hypertensive patients (SBP ≥ 140 mmHg in Month 1), there were significant differences in pre- and post-dialysis SBP between Month 1 and Month 12 (pre-hemodialysis: p = 0.02; post-hemodialysis: p = 0.0003), and antihypertensive medication use decreased in 29% of patients, while only 11% increased use. Treatment time in hypertensive patients increased by 15.4 minutes (p = 0.0005).

LIMITATIONS

This was a single, clinic-wide, quality improvement project with no control group. All data analyzed were from existing clinical records, so only routinely measured clinical variables were available and missing data were possible.

CONCLUSIONS

During this year-long fluid management quality improvement project, decreases in post-dialysis SBP and increases in adequacy and treatment time were observed. Patients with hypertension at Month 1 experienced reductions in pre-dialysis SBP and antihypertensive medications.

Euvolemia in hemodialysis patients: a potentially dangerous goal?

Dialysis patients have high mortality rate and the leading cause of death is cardiovascular disease. Uremic cardiomyopathy differs from that due to conventional atherosclerosis, where cardiovascular changes result in ineffective circulation and lead to tissue ischemia. Modern dialysis has significant limitations with fluid management probably the most challenging. Current evidence suggests that both volume overload and aggressive fluid removal can induce circulatory stress and multi-organ injury. Furthermore, we do not have accurate volume assessment tools. As a result, targeting euvolemia might result in more harm than benefit with conventional hemodialysis therapy. Therefore, it might be time to consider a degree of permissive over-hydration until we have better tools to both determine ideal weight and improve current renal replacement therapy so that the process of achieving it is not so fraught with the current dangers.

Assessment and management of hypertension in patients on dialysis

Hypertension is common, difficult to diagnose, and poorly controlled among patients with ESRD. However, controversy surrounds the diagnosis and treatment of hypertension. Here, we describe the diagnosis, epidemiology, and management of hypertension in dialysis patients, and examine the data sparking debate over appropriate methods for diagnosing and treating hypertension. Furthermore, we consider the issues uniquely related to hypertension in pediatric dialysis patients. Future clinical trials designed to clarify the controversial results discussed here should lead to the implementation of diagnostic and therapeutic techniques that improve long-term cardiovascular outcomes in patients with ESRD.

Whole-body single-frequency bioimpedance analysis in pediatric hemodialysis patients

BACKGROUND

We hypothesized that the percent change in resistance (%RΔ) from bioimpedance analysis (BIA) measurements during hemodialysis (HD) can provide information on pediatric HD patients' hydration status.

METHODS

Whole-body single-frequency BIA measurements were obtained before HD, each hour on HD, and after HD during two HD sessions. Pre-and post-HD weights, blood pressures, Crit-Line® measurements, and intradialytic symptoms were collected on the day of the BIA measurements.

RESULTS

One hundred and thirty BIA measurements were obtained from 14 HD patients. The group was 43 % girls, and the mean age was 13.2 ± 4.4 years. Percent change in resistance was 13.5 ± 10.8 % at the end of HD; %RΔ correlated with percent body weight change (%BWΔ) following HD (r = -0.83, P < 0.01), as well as with percent blood volume change (%BVΔ) (r = -0.79, P < 0.01). The %RΔ was similar between patients with and without hypertension immediately before HD and was greater in those with intradialytic symptoms (19.1 ± 7.7 %) than in those without (9.9 ± 11.2 %) (P = 0.02). Patients with left ventricular hypertrophy (LVH) had lower %RΔ (7.2 ± 9.7 %) than those without (19.5 ± 7.7 %) (P = 0.03). Left ventricular mass index (LVMI) also correlated strongly with %RΔ (r = -0.79, P = 0.004) and %BWΔ (r = 0.82, P = 0.002).

CONCLUSIONS

Our study showed that %RΔ strongly correlates with %BWΔ and %BVΔ and that %RΔ also correlated with intradialytic symptoms and LVMI.

Effects of Crit-Line® monitor use on patient outcomes and epoetin alfa dosing following onset of hemodialysis: a propensity score-matched study

BACKGROUND

The Crit-Line® monitor (CLM) is a device for monitoring hematocrit, oxygen saturation and change in intravascular blood volume during hemodialysis. Prior studies have evaluated CLM use in dialysis patients, but not specifically in those new to dialysis.

METHODS

In this retrospective analysis, 199 patients initiating dialysis at 8 facilities routinely using CLM were compared with 796 propensity score-matched non-CLM patients initiating dialysis at facilities not using CLM. Outcomes were considered over the first 180 days on dialysis.

RESULTS

Overall, the CLM group had higher StdKt/V (p = 0.06) and received lower doses of intravenous iron than the non-CLM group (p < 0.001). Erythropoiesis-stimulating agent doses were lower in the CLM group in months 1-5. Serum iron and transferrin saturation levels were higher overall for the CLM group than the non-CLM group (p = 0.004 and 0.01, respectively). Hemoglobin levels and time to first hospitalization were similar for both groups.

CONCLUSION

Use of CLM is associated with lower erythropoiesis-stimulating agent and iron use in incident hemodialysis patients.

Can Nephrologists Use Ultrasound to Evaluate the Inferior Vena Cava? A Cross-Sectional Study of the Agreement between a Nephrologist and a Cardiologist

Background/Aims

The costs and the need for a specialist impair the implementation of ultrasonography for evaluating the inferior vena cava (IVC) to assess the volemic status in hemodialysis patients. We investigated whether a nephrologist with limited ultrasound training can accurately assess the IVC in patients undergoing hemodialysis.

Methods

A cardiologist and a nephrologist consecutively measured the indexed IVC expiratory diameter (VCDi) and the IVC collapsibility index (IVCCI) of 52 patients during hemodialysis sessions. In protocol I, the nephrologist used a regular ultrasound system (RUS) and the cardiologist used a cardiovascular ultrasound equipment; in protocol II, the machines were interchanged. Pearson and kappa coefficients and the interexaminer agreement by the Bland-Altman method were calculated.

Results

The VCDi measurements showed a strong correlation in both protocols (r = 0.88 and 0.84 in protocols I and II, respectively). The volemic classifications were excellent in protocol I (kappa = 0.82 and 0.93 by VCDi and IVCCI, respectively) and substantial in protocol II (kappa = 0.77 and 0.75 by VCDi and IVCCI, respectively). The interexaminer agreement on the VCDi measurements was very good in both protocols.

Conclusions

Ultrasound evaluation of the IVC can be performed by nephrologists using an RUS to assess the volemic status in hemodialysis patients.

Hypertension in hemodialysis patients treated with atenolol or lisinopril: a randomized controlled trial

BACKGROUND

The purpose of this study was to determine among maintenance hemodialysis patients with echocardiographic left ventricular hypertrophy and hypertension whether in comparison with a β-blocker-based antihypertensive therapy, an angiotensin converting enzyme-inhibitor-based antihypertensive therapy causes a greater regression of left ventricular hypertrophy.

METHODS

Subjects were randomly assigned to either open-label lisinopril (n = 100) or atenolol (n = 100) each administered three times per week after dialysis. Monthly monitored home blood pressure (BP) was controlled to <140/90 mmHg with medications, dry weight adjustment and sodium restriction. The primary outcome was the change in left ventricular mass index (LVMI) from baseline to 12 months.

RESULTS

At baseline, 44-h ambulatory BP was similar in the atenolol (151.5/87.1 mmHg) and lisinopril groups, and improved similarly over time in both groups. However, monthly measured home BP was consistently higher in the lisinopril group despite the need for both a greater number of antihypertensive agents and a greater reduction in dry weight. An independent data safety monitoring board recommended termination because of cardiovascular safety. Serious cardiovascular events in the atenolol group occurred in 16 subjects, who had 20 events, and in the lisinopril group in 28 subjects, who had 43 events {incidence rate ratio (IRR) 2.36 [95% confidence interval (95% CI) 1.36-4.23, P = 0.001]}. Combined serious adverse events of myocardial infarction, stroke and hospitalization for heart failure or cardiovascular death in the atenolol group occurred in 10 subjects, who had 11 events and in the lisinopril group in 17 subjects, who had 23 events (IRR 2.29, P = 0.021). Hospitalizations for heart failure were worse in the lisinopril group (IRR 3.13, P = 0.021). All-cause hospitalizations were higher in the lisinopril group [IRR 1.61 (95% CI 1.18-2.19, P = 0.002)]. LVMI improved with time; no difference between drugs was noted.

CONCLUSIONS

Among maintenance dialysis patients with hypertension and left ventricular hypertrophy, atenolol-based antihypertensive therapy may be superior to lisinopril-based therapy in preventing cardiovascular morbidity and all-cause hospitalizations. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases; ClinicalTrials.gov number: NCT00582114).

Ambulatory blood pressure in chronic kidney disease

Chronic kidney disease (CKD) affects approximately 20 million adults in the United States. Patients with CKD have an increased risk of cardiovascular (CV) disease. Ambulatory blood pressure monitoring (ABPM) provides superior BP measurements when compared to office BP measurements in normotensive, hypertensive and CKD patients. ABPM measurements are often abnormal in CKD, with CKD patients frequently showing an altered circadian rhythm with an increased rate of non-dipping and reverse dipping. The prevalence of non-dippers and reverse-dippers increases progressively as stage of CKD progresses. ABPM has been shown to be a better tool for predicting CV risk, CKD progression, end stage renal disease (ESRD) or death than office-based pressures. ABPM is also additive and adds prognostic value for predicting CKD and CV outcomes when added to estimated glomerular filtration rate (eGFR). Although ABPM is time consuming, it is worth considering, as the data demonstrates that information from ABPM can potentially impact future CV and renal outcomes in patients with CKD.

Fluid overload in hemodialysis patients: a cross-sectional study to determine its association with cardiac biomarkers and nutritional status

Background

Chronic fluid overload is associated with higher mortality in dialysis patients; however, the link with cardiovascular morbidity has not formally been established and may be influenced by subclinical inflammation. We hypothesized that a relationship exists between fluid overload and [i] cardiovascular laboratory parameter as well as between fluid overload and [ii] inflammatory laboratory parameters. In addition, we aimed to confirm whether volume status correlates with nutritional status.

Methods

We recorded baseline characteristics of 244 hemodialysis patients at three hemodialysis facilities in Vienna (Austria) and determined associations with volume measurements using the body composition monitor (Fresenius/Germany). In one facility comprising 126 patients, we further analyzed cardiovascular, inflammatory and nutritional parameters.

Results

We detected predialysis fluid overload (FO) in 39% of all patients (n = 95) with FO defined as ≥15% of extracellular water (ECW). In this subgroup, the absolute FO was 4.4 +/-1.5 L or 22.9 ± 4.8% of ECW. A sub-analysis of patients from one center showed that FO was negatively associated with body mass index (r = -0.371; p = <0.001), while serum albumin was significantly lower in fluid overloaded patients (p = 0.001). FO was positively associated with D-Dimer (r = 0.316; p = 0.001), troponin T (r = 0.325; p < 0.001), and N-terminal pro-B-type natriuretic peptide (r = 0.436; p < 0.001), but not with investigated inflammatory parameters.

Conclusions

Fluid overload in HD patients was found to be lower in patients with high body mass index, indicating that dry weight was inadequately prescribed and/or difficult to achieve in overweight patients. The association with parameters of cardiovascular compromise and/or damage suggests that fluid overload is a biomarker for cardiovascular risk. Future studies should determine if this applies to patients prior to end-stage renal disease.

Significance of interdialytic weight gain versus chronic volume overload: consensus opinion

Predialysis volume overload is the sum of interdialytic weight gain (IDWG) and residual postdialysis volume overload. It results mostly from failure to achieve an adequate volume status at the end of the dialysis session. Recent developments in bioimpedance spectroscopy and possibly relative plasma volume monitoring permit noninvasive volume status assessment in hemodialysis patients. A large proportion of patients have previously been shown to be chronically volume overloaded predialysis (defined as >15% above 'normal' extracellular fluid volume, equivalent to >2.5 liters on average), and to exhibit a more than twofold increased mortality risk. By contrast, the magnitude of the mortality risk associated with IDWG is much smaller and only evident with very large weight gains. Here we review the available evidence on volume overload and IDWG, and question the use of IDWG as an indicator of 'nonadherence' by describing its association with postdialysis volume depletion. We also demonstrate the relationship between IDWG, volume overload and predialysis serum sodium concentration, and comment on salt intake. Discriminating between volume overload and IDWG will likely lead to a more appropriate management of fluid withdrawal during dialysis. Consensually, the present authors agree that this discrimination should be among the primary goals for dialysis caretakers today. In consequence, we recommend objective measures of volume status beyond mere evaluations of IDWG.

Pulmonary congestion predicts cardiac events and mortality in ESRD

Pulmonary congestion is highly prevalent and often asymptomatic among patients with ESRD treated with hemodialysis, but whether its presence predicts clinical outcomes is unknown. Here, we tested the prognostic value of extravascular lung water measured by a simple, well validated ultrasound B-lines score (BL-US) in a multicenter study that enrolled 392 hemodialysis patients. We detected moderate-to-severe lung congestion in 45% and very severe congestion in 14% of the patients. Among those patients with moderate-to-severe lung congestion, 71% were asymptomatic or presented slight symptoms of heart failure. Compared with those patients having mild or no congestion, patients with very severe congestion had a 4.2-fold risk of death (HR=4.20, 95% CI=2.45-7.23) and a 3.2-fold risk of cardiac events (HR=3.20, 95% CI=1.75-5.88) adjusted for NYHA class and other risk factors. Including the degree of pulmonary congestion in the model significantly improved the risk reclassification for cardiac events by 10% (P<0.015). In summary, lung ultrasound can detect asymptomatic pulmonary congestion in hemodialysis patients, and the resulting BL-US score is a strong, independent predictor of death and cardiac events in this population.

Aldosterone and mortality in hemodialysis patients: role of volume overload

BACKGROUND

Elevated aldosterone is associated with increased mortality in the general population. In patients on dialysis, however, the association is reversed. This paradox may be explained by volume overload, which is associated with lower aldosterone and higher mortality.

METHODS

We evaluated the relationship between aldosterone and outcomes in a prospective cohort of 328 hemodialysis patients stratified by the presence or absence of volume overload (defined as extracellular water/total body water >48%, as measured with bioimpedance). Baseline plasma aldosterone was measured before dialysis and categorized as low (<140 pg/mL), middle (140 to 280 pg/mL) and high (>280 pg/mL).

RESULTS

Overall, 36% (n = 119) of the hemodialysis patients had evidence of volume overload. Baseline aldosterone was significantly lower in the presence of volume overload than in its absence. During a median follow-up of 54 months, 83 deaths and 70 cardiovascular events occurred. Cox multivariate analysis showed that by using the low aldosterone as the reference, high aldosterone was inversely associated with decreased hazard ratios for mortality (0.49; 95% confidence interval, 0.25-0.76) and first cardiovascular event (0.70; 95% confidence interval, 0.33-0.78) in the presence of volume overload. In contrast, high aldosterone was associated with an increased risk for mortality (1.97; 95% confidence interval, 1.69-3.75) and first cardiovascular event (2.01; 95% confidence interval, 1.28-4.15) in the absence of volume overload.

CONCLUSIONS

The inverse association of aldosterone with adverse outcomes in hemodialysis patients is due to the confounding effect of volume overload. These findings support treatment of hyperaldosteronemia in hemodialysis patients who have achieved strict volume control.

Shorter delivered dialysis times associate with a higher and more difficult to treat blood pressure

BACKGROUND

Shorter delivered dialysis times are associated with increased all-cause mortality. Whether shorter delivered dialysis times also associate with an increase in blood pressure (BP) and reduce the ability of probing dry weight to lower BP is unclear.

METHODS

Among patients participating in the Dry-Weight Reduction in Hypertensive Hemodialysis Patients (DRIP) trial, interdialytic ambulatory BP was recorded at baseline, 4 weeks and 8 weeks. Median intradialytic BP was also calculated at each dialysis treatment and associated with the delivered daily dialysis time.

RESULTS

The median time on dialysis at baseline was 3.6 h per treatment (range 2.5-4.5 h). At baseline, modeled median intradialytic systolic BPs were higher among those who received fewer hours of dialysis. Among subjects who did not have their dry weight probed (control group), the median intradialytic systolic BP continued to be elevated. Probing dry weight (ultrafiltration group) provoked a drop in median intradialytic systolic BP regardless of the delivered dialysis time. However, the reduction in BP was achieved after fewer sessions of dialysis when delivered dialysis was longer in duration. The pattern of change was confirmed using interdialytic ambulatory BP monitoring.

CONCLUSIONS

Fewer hours of delivered dialysis are associated with a higher systolic BP. Upon probing dry weight, compared with shorter dialysis treatment times, 4 h of delivered dialysis per session provokes reductions in systolic BP over fewer dialysis treatment sessions. Reduction of BP may lag dry-weight reduction when shorter dialysis is delivered.

Relative Change in NT-proBNP Level: An Important Risk Predictor of Cardiovascular Congestion in Haemodialysis Patients

Background

Cross-sectional studies have shown that B-type natriuretic peptide (BNP) and its N-terminal fragment (NT-proBNP) are predictive of cardiovascular death in haemodialysis (HD) patients. In the present study, we tested the hypothesis that monitoring NT-proBNP measurements adds further prognostic information, i.e. predicts congestive heart failure (CHF) events.

Methods

In a prospective cohort of 236 HD patients, NT-proBNP levels were measured monthly during 18 months. Patients were divided according to the occurrence of CHF events. In a nested case-control study, we assessed the evolution of NT-proBNP levels.

Results

On average, the 236 HD patients were followed up for 12.5 months, a period during which 44 patients developed a CHF event (half requiring hospitalisation). At baseline, patients who developed a CHF event had significantly more dilated cardiomyopathy and/or altered left ventricular ejection fraction and higher NT-proBNP levels compared with patients who did not develop a CHF event. During follow-up, we observed a significant increase in NT-proBNP levels preceding the CHF event. At a 20% relative increase of NT-proBNP, the sensitivity of NT-proBNP as a predictor of CHF events was 0.57 and the specificity 0.77.

Conclusion

The relative change in NT-proBNP levels is a significant risk predictor of a CHF event.

Debate from the 2012 ASH Annual Scientific Sessions: should blood pressure be reduced in hemodialysis patients? Con position

The relationship between blood pressure and cardiovascular events in hemodialysis patients is complicated and controversial. The timing of blood pressure measurements (home, before dialysis, after dialysis, during dialysis) provide somewhat different results. Moreover, the use of antihypertensive medications may also confound the relationship between blood pressure and cardiovascular outcome. Most important may be the relationship between central blood volume/pressure and risk for cardiac events, specifically for congestive heart failure and sudden death. Achieving dry-weight during dialysis as opposed to a specific blood pressure level is the optimal strategy for reducing cardiovascular events in the hemodialysis patient.

Debate from the 2012 ASH Annual Scientific Sessions: should blood pressure be reduced in hemodialysis patients? Pro position

Among chronic hemodialysis patients with hypertension, blood pressure should be lowered. Blood pressure reduction with antihypertensive drugs does not increase mortality; in contrast, meta-analysis of randomized trials suggests that treatment of hypertension in this high-risk population may, in fact, improve cardiovascular outcomes. The association of low blood pressure with increased mortality in longitudinal studies should not be considered as evidence against lowering blood pressure. Lowering blood pressure among hypertensive patients should primarily be done by sodium restriction and dry-weight reduction. Treatment is perhaps better directed to home blood pressure than pre- or post-dialysis blood pressure recordings. Although no firm data are available, it appears that treating home blood pressure to <140/90 mm Hg appears reasonable. Nonetheless, all blood pressure recordings during dialysis are important to ensure patient safety. Adequately designed and powered randomized trials are needed to examine the notion that blood pressure lowering and, if so, to what level of blood pressure will improve clinically meaningful outcomes among chronic dialysis patients.

Determinants and short-term reproducibility of relative plasma volume slopes during hemodialysis

BACKGROUND AND OBJECTIVES

Hypervolemia is a major cause of morbidity, in part because of the lack of well characterized diagnostic tests. The hypothesis was that relative plasma volume (RPV) slopes are influenced by ultrafiltration rate, directly associate with improvement in arterial oxygen saturation, and are reproducible.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

RPV slopes were measured on three consecutive hemodialysis sessions. Various relationships were tested using mixed models. Reproducibility was assessed by the intraclass correlation coefficient.

RESULTS

RPV slopes averaged 1.37 ± 1.45% per hour. The mean RPV slopes were steeper on the first dialysis of the week, which correlated with a higher ultrafiltration rate; RPV slope and ultrafiltration rate were directly related. Increasing ultrafiltration rate quartiles were associated with similar change in RPV in the first 1 hour of dialysis but steeper changes in RPV subsequently. A direct relationship emerged between increasing RPV slopes and increasing arterial oxygen saturation slopes. The intraclass correlation coefficient for the relative plasma volume slope was 0.77.

CONCLUSIONS

Although ultrafiltration rate is a major determinant of RPV slope, similar ultrafiltration rates are associated with varying RPV between individuals. Because RPV is associated with little change by ultrafiltration rate during the first 1 hour of dialysis, probing dry weight during the earlier part of dialysis may be safer. RPV slopes are physiologically meaningful, because they are associated with parallel changes in arterial oxygenation saturation slopes. RPV slopes are reproducible, and therefore, RPV may serve as a useful marker to judge changes in volume status within an individual.

The controversies of diagnosing and treating hypertension among hemodialysis patients

This review discusses 10 current controversies regarding the dialysis patient with hypertension. The clinician is faced with a dilemma at the bedside on how to evaluate blood pressure and treat this condition in a patient on long-term hemodialysis. The evidence base to give firm recommendations is thin, but the epidemiological evidence tells us to do nothing. This appears to be an incorrect strategy, at least based on what we know today. Evaluating home BP in every dialysis patient, evaluating volume status on a regular basis, and treating hypertension predominantly with nonpharmacological strategies are worthwhile.

Comparison of volume status in asymptomatic haemodialysis and peritoneal dialysis outpatients

BACKGROUND

The majority of haemodialysis (HD) patients gain weight between dialysis sessions and thereby become volume overloaded, whereas peritoneal dialysis (PD) is a more continuous technique. Cardiovascular mortality and hypertension is increased with both treatment modalities. We therefore wished to compare volume status in PD and HD to determine whether PD patients are chronically volume overloaded, as a risk factor for cardiovascular mortality. Study Design, Setting and Participants:We retrospectively audited 72 healthy HD patients and 115 healthy PD patients attending a university hospital dialysis centre for routine outpatient treatment, who had multi-frequency bioimpedance measurements of extracellular water to total body water (ECW/TBW).

RESULTS

The groups were well matched for age, sex, weight and ethnicity, PD patients had greater urine output [1,075 (485-1,613) vs. 42.5 (0-1,020) ml/day, p < 0.001], but there was no difference in antihypertensive prescription (63.5 vs. 76.4%), mean arterial blood pressure (post-dialysis 101.6 ± 1.5 mm Hg vs. pre-dialysis 102 ± 2.4 mm Hg), although post-dialysis arterial blood pressure was lower than in PD patients (96.4 ± 3.1 mm Hg, p < 0.05). The ratio of ECW/TBW fell after HD (pre-dialysis 0.394 ± 0.001 vs. post-dialysis 0.389 ± 0.004, p < 0.001) and was similar in the PD group to the group before HD (0.393 ± 0.001), and greater than that in the group after HD (p < 0.001). ECW/TBW was greater than the normal reference range in 30% PD patients, 28% patients before HD and 20% patients after HD.

CONCLUSIONS

Overhydration is common in healthy stable PD outpatients, and ECW volumes in PD patients are not dissimilar to those of pre-dialysis HD patients. The role of chronic volume overload as a risk factor for cardiovascular disease needs further investigation.

Hypertension and hemodialysis: pathophysiology and outcomes in adult and pediatric populations

Hypertension is prevalent in adult and pediatric end-stage renal disease patients on hemodialysis. Volume overload is a primary factor contributing to hypertension, and attaining true dry weight remains a priority for nephrologists. Other contributing factors to hypertension include activation of the sympathetic and renin-angiotensin-aldosterone systems, endothelial cell dysfunction, arterial stiffness, exposure to hypertensinogenic drugs, and electrolyte imbalances during hemodialysis. Epidemiologic studies in adults show that uncontrolled hypertension results in cardiovascular morbidity, but reveal increased mortality risk at low blood pressure, so that it remains unclear what the target blood pressure should be. Despite the lack of a definitive BP target, gradual dry weight reduction should be the first intervention for BP control. Renin-angiotensin-aldosterone system inhibitors have been shown to improve cardiovascular morbidity and mortality and are recommended as the initial pharmacologic therapy for hypertensive hemodialysis patients. Short-daily or nocturnal hemodialysis are also good therapeutic options for these patients. It is already established that hypertension in pediatric hemodialysis patients is associated with adverse cardiovascular outcomes, and there is emerging evidence that the mechanisms causing hypertension are similar to adults. Hypertension in adult and pediatric hemodialysis patients warrants aggressive management, although clinical trial evidence of a target BP that improves mortality does not currently exist.

Dialysate sodium concentration and the association with interdialytic weight gain, hospitalization, and mortality

BACKGROUND AND OBJECTIVES

Recommendations to decrease the dialysate sodium (DNa) prescription demand analyses of patient outcomes. We analyzed morbidity and mortality at various levels of DNa, simultaneously accounting for interdialytic weight gain (IDWG) and for the mortality risk associated with lower predialysis serum sodium (SNa) levels.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used multiply-adjusted linear mixed models to evaluate the magnitude of IDWG and Cox proportional hazards models to assess hospitalizations and deaths in 29,593 patients from the Dialysis Outcomes and Practice Patterns Study with baseline DNa and SNa as predictors, categorized according to lowest to highest levels.

RESULTS

IDWG increased with higher DNa across all SNa categories, by 0.17% of body weight per 2 mEq/L higher DNa; however, higher DNa was not associated with higher mortality in a fully adjusted model (also adjusted for SNa; hazard ratio [HR]=0.98 per 2 mEq/L higher DNa, 95% confidence interval [CI] 0.95-1.02). Instead, higher DNa was associated with lower hospitalization risk (HR=0.97 per 2 mEq/L higher DNa, 95% CI 0.95-1.00, P=0.04). Additional adjustments for IDWG did not change these results. In sensitivity analyses restricted to study facilities, in which 90%-100% of patients have the same DNa (56%), the adjusted HR for mortality was 0.88 per 2 mEq/L higher DNa (95% CI 0.83-0.94). These analyses represented a pseudo-randomized experiment in which the association between DNa and mortality is unlikely to have been confounded by indication.

CONCLUSIONS

In the absence of randomized prospective studies, the benefit of reducing IDWG by decreasing DNa prescriptions should be carefully weighed against an increased risk for adverse outcomes.