Hemodialysis-associated hypertension: pathophysiology and therapy

Does Renal Denervation a Reasonable Treatment Option in Hemodialysis-Dependent Patient with Resistant Hypertension? A Narrative Review

PURPOSE OF REVIEW

This narrative review aims to assess the pathophysiology, diagnosis, and treatment of resistant hypertension (RH) in end-stage kidney disease (ESKD) patients on dialysis, with a specific focus on the effect of renal denervation (RDN) on short-term and long-term blood pressure (BP) control. Additionally, we share our experience with the use of RDN in an amyloidotic patient undergoing hemodialysis with RH.

RECENT FINDINGS

High BP, an important modifiable cardiovascular risk factor, is often observed in patients in ESKD, despite the administration of multiple antihypertensive medications. However, in clinical practice, it remains challenging to identify RH patients on dialysis treatment because of the absence of specific definition for RH in this context. Moreover, the use of invasive approaches, such as RDN, to treat RH is limited by the exclusion of patients with reduced renal function (eGFR < 45 mL/min/1.73 m3) in the clinical trials. Nevertheless, recent studies have reported encouraging results regarding the effectiveness of RDN in stage 3 and 4 chronic kidney disease (CKD) and ESKD patients on dialysis, with reductions in BP of nearly up to 10 mmhg. Although multiple underlying pathophysiological mechanisms contribute to RH, the overactivation of the sympathetic nervous system in ESKD patients on dialysis plays a crucial role. The diagnosis of RH requires both confirmation of adherence to antihypertensive therapy and the presence of uncontrolled BP values by ambulatory BP monitoring or home BP monitoring. Treatment involves a combination of nonpharmacological approaches (such as dry weight reduction, sodium restriction, dialysate sodium concentration reduction, and exercise) and pharmacological treatments. A promising approach for managing of RH is based on catheter-based RDN, through radiofrequency, ultrasound, or alcohol infusion, directly targeting on sympathetic overactivity.

Predicting dry weight change in Hemodialysis patients using machine learning

BACKGROUND

Machine Learning has been increasingly used in the medical field, including managing patients undergoing hemodialysis. The random forest classifier is a Machine Learning method that can generate high accuracy and interpretability in the data analysis of various diseases. We attempted to apply Machine Learning to adjust dry weight, the appropriate volume status of patients undergoing hemodialysis, which requires a complex decision-making process considering multiple indicators and the patient's physical conditions.

METHODS

All medical data and 69,375 dialysis records of 314 Asian patients undergoing hemodialysis at a single dialysis center in Japan between July 2018 and April 2020 were collected from the electronic medical record system. Using the random forest classifier, we developed models to predict the probabilities of adjusting the dry weight at each dialysis session.

RESULTS

The areas under the receiver-operating-characteristic curves of the models for adjusting the dry weight upward and downward were 0.70 and 0.74, respectively. The average probability of upward adjustment of the dry weight had sharp a peak around the actual change over time, while the average probability of downward adjustment of the dry weight formed a gradual peak. Feature importance analysis revealed that median blood pressure decline was a strong predictor for adjusting the dry weight upward. In contrast, elevated serum levels of C-reactive protein and hypoalbuminemia were important indicators for adjusting the dry weight downward.

CONCLUSIONS

The random forest classifier should provide a helpful guide to predict the optimal changes to the dry weight with relative accuracy and may be useful in clinical practice.

Effect of end-stage kidney disease on the return of spontaneous circulation in Taiwanese adults with out-of-hospital cardiac arrest

Rescuing patients with out-of-hospital cardiac arrest (OHCA), especially those with end-stage kidney disease (ESKD), is challenging. This study hypothesizes that OHCA patients with ESKD undergoing maintenance hemodialysis have (1) higher rates of return of spontaneous circulation (ROSC) during cardio-pulmonary resuscitation (CPR) and (2) lower rates of hyperkalemia and less severe acidosis than those without ESKD. OHCA patients who received CPR between 2011 and 2020 were dichotomized into ESKD and non-ESKD groups. The association of ESKD with "any" and "sustained" ROSC were examined using logistic regression analysis. Furthermore, the effect of ESKD on hospital outcomes for OHCA patients who survived to admission was evaluated using Kaplan-Meier analysis. ESKD patients without "any" ROSC displayed lower potassium and higher pH levels than non-ESKD patients. ESKD was positively associated with "any" ROSC (adjusted-OR: 4.82, 95% CI 2.70-5.16, P < 0.01) and "sustained" ROSC (adjusted-OR: 9.45, 95% CI 3.83-24.13, P < 0.01). Kaplan-Meier analysis demonstrated ESKD patients had a non-inferior hospital survival than non-ESKD patients. OHCA patients with ESKD had lower serum potassium level and less severe acidosis compared to the general population in Taiwan; therefore, should not be treated under the stereotypical assumption that hyperkalemia and acidosis always occur.

Application of deep learning to predict the low serum albumin in new hemodialysis patients

BACKGROUND

Serum albumin level is a crucial nutritional indicator for patients on dialysis. Approximately one-third of patients on hemodialysis (HD) have protein malnutrition. Therefore, the serum albumin level of patients on HD is strongly correlated with mortality.

METHODS

In study, the data sets were obtained from the longitudinal electronic health records of the largest HD center in Taiwan from July 2011 to December 2015, included 1,567 new patients on HD who met the inclusion criteria. Multivariate logistic regression was performed to evaluate the association of clinical factors with low serum albumin, and the grasshopper optimization algorithm (GOA) was used for feature selection. The quantile g-computation method was used to calculate the weight ratio of each factor. Machine learning and deep learning (DL) methods were used to predict the low serum albumin. The area under the curve (AUC) and accuracy were calculated to determine the model performance.

RESULTS

Age, gender, hypertension, hemoglobin, iron, ferritin, sodium, potassium, calcium, creatinine, alkaline phosphatase, and triglyceride levels were significantly associated with low serum albumin. The AUC and accuracy of the GOA quantile g-computation weight model combined with the Bi-LSTM method were 98% and 95%, respectively.

CONCLUSION

The GOA method was able to rapidly identify the optimal combination of factors associated with serum albumin in patients on HD, and the quantile g-computation with DL methods could determine the most effective GOA quantile g-computation weight prediction model. The serum albumin status of patients on HD can be predicted by the proposed model and accordingly provide patients with better a prognostic care and treatment.

Risk factors for intracerebral hemorrhage in patients undergoing maintenance hemodialysis

Background

In patients undergoing hemodialysis, intracerebral hemorrhage (ICH) is the main cause of mortality among stroke subtypes. It is unclear whether, along with traditional cardiovascular risk factors, the risk factors unique to the uraemic environment, such as the abnormal metabolism of intact parathyroid hormone (iPTH), can contribute to the risk of ICH in these patients.

Methods

This retrospective case-control study included 25 patients undergoing hemodialysis with ICH at a single center between 30 June 2015 and 10 October 2022. The controls were 95 patients undergoing maintenance hemodialysis treated at the same dialysis center in July 2020. We compared the characteristics of patients with ICH with those of the control group to identify factors that contributed to the development of ICH.

Results

Intracerebral hemorrhage (ICH) was located in the basal ganglia (14/25), cerebellum (6/25), and brainstem (6/25) in 25 patients. A total of 17 patients died in the first 16 days due to neurological complications. Univariate analysis showed significant differences in systolic BP, diastolic BP, iPTH, and alkaline phosphatase between the two groups (p < 0.05). Multivariate logistic regression analysis showed that higher systolic BP (OR, 1.053; 95% CI, 1.018-1.090; p = 0.003) and higher iPTH (OR, 1.007; 95% CI, 1.003-1.012; p = 0.001) were associated with the onset of ICH. ICH was predicted by systolic BP and iPTH by receiver operating characteristic (ROC) curve analysis, with areas under the curve (AUCs) of 0.732 and 0.624, respectively. The optimal cutoffs for systolic BP and iPTH were 151.9 mmHg and 295.4 pg./ml, respectively. Restricted cubic spline showed that the shape of the association of iPTH with the risk of ICH was approximately J-shaped (P for non-linearity <0.05).

Conclusion

Higher systolic BP and abnormal iPTH metabolism might be associated with ICH in patients undergoing hemodialysis. Comprehensive control of hypertension and iPTH may be a fundamental preventive strategy for ICH in these patients.

Correlation between Angiotensin Serum Levels and Very-Low-Frequency Spectral Power of Heart Rate Variability during Hemodialysis

Cardiovascular regulatory mechanisms that fail to compensate for ultrafiltration and cause hypovolemia during hemodialysis (HD) are not completely understood. This includes the interaction between the autonomic nervous system and the biochemistry that regulates blood pressure and modulates cardiac activity and vascular tone in response to hypovolemia in patients treated with HD. The objective was to evaluate the association of spectral indices of heart rate variability (HRV) with serum levels of angiotensin II, angiotensin 1–7, nitric oxide and total antioxidant capacity during HD. Electrocardiographic records were obtained from 20 patients during HD (3 h), from which HRV data and spectral power data in the very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF) bands were generated. Three blood samples per patient were collected during HD (0.0, 1.5, 3.0 h) to determine the levels of biomarkers involved in the pressor response during HD. Angiotensin II had a positive correlation with VLF (r = 0.390) and with LF/HF (r = 0.359) and a negative correlation with LF (r = −0.262) and HF (r = −0.383). There were no significant correlations between HRV and the other biomarkers. These results suggest that during HD, VLF could reflect the serum levels of angiotensin II, which may be associated with the autonomic response to HD.

Influence of Intraoperative Hemodynamic Parameters on Outcome in Simultaneous Pancreas-Kidney Transplant Recipients

Objectives: Adequate organ perfusion, as well as appropriate blood pressure levels at the time of unclamping, is crucial for early and long-term graft function and outcome in simultaneous pancreas−kidney transplantation (SPKT). However, the optimal intraoperative mean arterial pressure (MAP) level has not well been defined. Methods: From a prospectively collected database, the medical data of 105 patients undergoing SPKT at our center were retrospectively analyzed. A receiver operating characteristic (ROC) analysis was preliminarily performed for optimal cut-off value for MAP at reperfusion, to predict early pancreatic graft function. Due to these results, we divided the patients according to their MAP values at reperfusion into <91 mmHg (n = 47 patients) and >91 mmHg (n = 58 patients) groups. Clinicopathological characteristics and outcomes, as well as early graft function and long-term survival, were retrospectively analyzed. Results: Donor and recipient characteristics were comparable between both groups. Rates of postoperative complications were significantly higher in the <91 mmHg group than those in the >91 mmHg group (vascular thrombosis of the pancreas: 7 (14%) versus 2 (3%); p = 0.03; pancreatitis/intraabdominal abscess: 10 (21%) versus 4 (7%); p = 0.03; renal delayed graft function (DGF): 11 (23%) versus 5 (9%); p = 0.03; postreperfusion urine output: 106 ± 50 mL versus 195 ± 45 mL; p = 0.04). There were no significant differences in intraoperative volume repletion, central venous pressure (CVP), use of vasoactive inotropic agents, and the metabolic outcome. Five-year pancreas graft survival was significantly higher in the >91 mmHg group (>91 mmHg: 82% versus <91 mmHg: 61%; p < 0.01). No significant differences were observed in patient and kidney graft survival at 5 years between both groups. Multivariate Cox regression analysis affirmed MAP < 91 mmHg as an independent prognostic predictor for renal DGF (HR 3.49, 1.1−10.8, p = 0.03) and pancreas allograft failure (HR 2.26, 1.0−4.8, p = 0.01). Conclusions: A MAP > 91 mmHg at the time point of reperfusion was associated with a reduced rate of postoperative complications, enhancing and recovering long-term graft function and outcome and thus increasing long-term survival in SPKT recipients.

Assessment of cerebral oxygenation response to hemodialysis using near-infrared spectroscopy (NIRS): Challenges and solutions

To date, the clinical use of functional near-infrared spectroscopy (NIRS) to detect cerebral ischemia has been largely limited to surgical settings, where motion artifacts are minimal. In this study, we present novel techniques to address the challenges of using NIRS to monitor ambulatory patients with kidney disease during approximately eight hours of hemodialysis (HD) treatment. People with end-stage kidney disease who require HD are at higher risk for cognitive impairment and dementia than age-matched controls. Recent studies have suggested that HD-related declines in cerebral blood flow might explain some of the adverse outcomes of HD treatment. However, there are currently no established paradigms for monitoring cerebral perfusion in real-time during HD treatment. In this study, we used NIRS to assess cerebral hemodynamic responses among 95 prevalent HD patients during two consecutive HD treatments. We observed substantial signal attenuation in our predominantly Black patient cohort that required probe modifications. We also observed consistent motion artifacts that we addressed by developing a novel NIRS methodology, called the HD cerebral oxygen demand algorithm (HD-CODA), to identify episodes when cerebral oxygen demand might be outpacing supply during HD treatment. We then examined the association between a summary measure of time spent in cerebral deoxygenation, derived using the HD-CODA, and hemodynamic and treatment-related variables. We found that this summary measure was associated with intradialytic mean arterial pressure, heart rate, and volume removal. Future studies should use the HD-CODA to implement studies of real-time NIRS monitoring for incident dialysis patients, over longer time frames, and in other dialysis modalities.

Blood Pressure Control and Antihypertensive Treatment among Hemodialysis Patients-Retrospective Single Center Experience

Background and Objectives: Hypertension affects at least 80% of hemodialysis patients. Inappropriate control of blood pressure is mentioned as one of the essential cardiovascular risk factors associated with development of cardiovascular events in dialysis populations. The aim of the cross-sectional, retrospective study was the evaluation of the antihypertensive treatment schedule and control of blood pressure in relation to the guidelines in the group of hemodialysis patients. Additionally, we assessed the level of decrease in blood pressure by each group of hypotensive agents. Materials and Methods: 222 patients hemodialyzed in a single Dialysis Unit in three distinct periods of time—2006, 2011, and 2016—with a diagnosis of hypertension were enrolled in the study. The analysis of the antihypertensive treatment was based on the medical files and it consisted of a comparison of the mean blood pressure results reported during the six consecutive hemodialysis sessions. Results: The mean values of blood pressure before hemodialysis were as follows: 134/77, 130/74, and 140/76 mmHg, after hemodialysis 124/74, 126/73, and 139/77 mmHg in 2006, 2011, and 2016 respectively. The goal of predialysis blood pressure control (<140/90) was achieved by up to 64.3% of participants in 2006 as compared to 49.4% in 2016. Additionally, the postdialysis goal (<130/90) reached 57.1% of the study population in 2006 as compared to 27.1% of patients in 2016. The differences in percentage of patients using single, double, triple, and multidrug therapy during observation were not statistically significant. The most often used drugs were ß-blockers, diuretics, and calcium channel blockers in all points of the study. Blockades of the renin–angiotensin–aldosterone system in 2006 and calcium channel blockers in 2011 and 2016 were the drugs with highest impact on lowering blood pressure. Conclusions: The goal of predialysis or postdialysis blood pressure control was achieved in a lower percentage of patients during the period of the study. Blockade of renin–angiotensin–aldosterone system and calcium channel blockers decrease the blood pressure significantly. It is necessary to achieve better control of blood pressure in prevention of cardiovascular incidents.

Effect of low dialysate sodium in the management of intradialytic hypertension in maintenance hemodialysis patients: A single-center Indian experience

BACKGROUND

High dialysate sodium is a significant contributor to intradialytic hypertension (IDH) in maintenance hemodialysis patients. In this study, we aimed to study the effect of low dialysate sodium on IDH in Indian hemodialysis patients.

MATERIALS AND METHODS

Fifty patients on maintenance hemodialysis for atleast 3 months with episodes of IDH were enrolled in this study. The study was performed in two different stages. In the first phase, patients were dialyzed with standard dialysate sodium (140 mEq/L) for eight consecutive sessions and in the second phase, they were dialyzed with low sodium dialysate (136 mEq/L) for eight consecutive sessions. Differences in pre, intradialytic, and post-HD blood pressure, interdialytic weight gain, mean serum sodium, intradialytic adverse events, and number of IDH episodes requiring intervention between the two phases were assessed.

RESULTS

The mean age of the study population was 52 years (36 males,14 females). The mean post-HD systolic and diastolic BP was 163.26 ± 9.58 mmHg and 88.60 ± 5.27 mmHg in the standard dialysate phase and 142.38 ± 14.09 mmHg and 84.58 ± 4.276 mmHg, respectively, in the low dialysate phase (p < 0.01). Interdialytic weight gain was 3.34 ± 0.9 and 3.11 ± 0.86 in the standard and low sodium dialysate phases, respectively (p = 0.19).The mean pre-HD plasma sodium level was 138.48 ± 3.69 and 135.80 ± 1.35 mEq/dl, respectively, in standard and low dialysate phases (p = 0.01). There was significant reduction in number of IDH episodes requiring intervention. There was no difference in hypotensive episodes, adverse events between the two phases.

CONCLUSION

In patients with intradialytic hypertension, low dialysate sodium significantly reduces the post-HD blood pressure and intradialytic hypertensive episodes, when compared with standard sodium dialysate.

Clinical Characteristics and Outcomes of Hemodialysis in a New Center in Northern Nigeria

BACKGROUND

Hemodialysis is the most common renal replacement therapy (RRT) modality in Africa and few countries enjoy reimbursement from the government to fund it. Africa contributes <10% of the total RRT patients worldwide this is mainly due to high cost.

AIMS AND OBJECTIVES

We aimed to review the clinical characteristics and outcomes of patients requiring hemodialysis in our center over a 7 years period, to highlight the enormous challenges encountered.

MATERIALS AND METHODS

This is a retrospective study of patients aged 15 years and above that was seen between April 2010 and March 2017 at the Hemodialysis unit of Abubakar Tafawa Balewa University Teaching Hospital. Information was extracted from the patient's case folders and dialysis charts.

RESULTS

In total, 226 patients had hemodialysis over the period, 124 (54.9%) were male and 102 (49.1%) were female. Sixty-one (27%) patients had acute kidney injury (AKI), 143 (63.3%) had chronic kidney disease (CKD), whereas 22 (9.7%) had acute-on-CKD. A total of 2215 sessions of hemodialysis were done in the period, of which 782 (35.3%) were for AKI and 469 (21.2%) for acute on CKD. A total of 138 (60.6%) patients were discharged and 58 deaths were recorded.

CONCLUSION

Although there is rapid proliferation of hemodialysis facilities in the country, many patients could not afford adequate hemodialysis. Inadequate dialysis due to finances was the main cause of death in these category of patients.

Interdialytic blood pressure variability and the risk of stroke in maintenance hemodialysis patients

Studies on nondialysis populations have linked visit-to-visit blood pressure (BP) variability (BPV) to cerebrovascular events and mortality. In view of the high prevalence of hypertension in hemodialysis patients, the predictive values of numerous factors for stroke, especially visit-to-visit BPV, were evaluated in this prospective cohort study.A total of 151 patients were enrolled in this study. The demographic features and various laboratory parameters were analyzed. At each routine hemodialysis visit, the predialysis, intradialysis, and post-dialysis BP measurements were systematically performed. We defined BPV using 4 metrics: standard deviation of the BP, coefficient of variation, average real variability (ARV), and variability independent of mean (VIM). Differences in the predialysis BPs from one treatment to the next (ie, interdialytic variability) and differences in the BPs from predialysis to post-dialysis (ie, intradialytic variability) were both studied in this work.Twenty-one patients developed stroke and 25 patients died. The multivariate Cox proportional hazards regression model revealed a significant relationship between stroke and the interdialytic BPV (both predialysis systolic BP variability and predialysis diastolic BP variability) and low-density lipoprotein-cholesterol (LDL-C).Our results indicate that a high interdialytic BPV is associated with an increased risk for stroke that is independent of several factors, including age, sex, antihypertensive medication use, and mean BP over time. There is potential that the optimal treatment goal for hemodialysis patients may be to reduce the interdialytic BPV rather than either the mean BP or the intradialytic BPV.

Optimizing Intraoperative Blood Pressure to Improve Outcomes in Living Donor Renal Transplantation

BACKGROUND

Adequate renal perfusion at the time of unclamping is important because it has been known to affect outcomes in renal transplantation. Nevertheless, the ideal intraoperative systolic arterial pressure (SAP) has not been well defined.

METHODS

We performed a retrospective analysis of 106 living donor renal transplants performed at our center from June 2010 to May 2019. We divided the cohort into 2 groups according to our center's goal SAP of ≥150 mm Hg: 57 patients had SAP ≥150 mm Hg and 49 patients had SAP <150 mm Hg. We analyzed pretransplant characteristics, intraoperative measurements, and postoperative laboratory values to validate our center's target SAP at the time of reperfusion. This study strictly complied with the Helsinki Congress and the Istanbul Declaration regarding donor sources.

RESULTS

Patients with SAP ≥150 mm Hg had been on dialysis for a significantly shorter duration before transplant compared with those who had SAP <150 mm Hg. In the SAP ≥150 mm Hg group, urinary sodium excretion normalized earlier, and they had a significantly smaller stroke volume variation, higher cardiac output and cardiac index, earlier initial urination, and higher intraoperative urine output. There were no differences in intraoperative volume repletion, central venous pressure, or postoperative estimated glomerular filtration rate.

CONCLUSION

Achieving SAP ≥150 mm Hg at the time of reperfusion may be associated with early stabilization of graft function. Nevertheless, our data suggested that recipients with a prolonged dialysis history are less likely to achieve SAP ≥150 mm Hg at the time of unclamping in living donor renal transplantation.

Serum BNP Concentration and Left Ventricular Mass in CAPD and Automated Peritoneal Dialysis Patients

Objective

To compare ultrafiltration under continuous ambulatory peritoneal dialysis (CAPD) and automated PD (APD), disclosing potential effects on serum B-type natriuretic peptide (BNP) levels and echocardiographic findings.

Patients and Methods

This cross-sectional clinical study included 32 patients on CAPD and 30 patients on APD without clinical evidence of heart failure or hemodynamically significant valvular heart disease. Peritoneal equilibration tests, BNP levels, and echocardiographic measurements were performed in each subject. BNP measurements were also performed in 24 healthy control subjects.

Results

Patients on APD had lower ultrafiltration and higher values of BNP and left ventricular mass index (LVMI) compared with patients on CAPD (respectively: 775 ± 160 vs 850 ± 265 mL, p = 0.01; 253.23 ± 81.64 vs 109.42 ± 25.63 pg/mL, p = 0.001; 185.12 ± 63.50 vs 129.30 ± 40.95 g/m2, p = 0.001). This occurred despite higher mean dialysate glucose concentrations and far more extensive use of icodextrin in the APD group.

Conclusion

Treatment with APD is associated with higher plasma BNP levels and LVMI compared to CAPD. This may be the result of chronic fluid retention caused by lower ultra-filtration in APD patients.

Anesthetic Considerations for Patients on Renal Replacement Therapy

The number of patients presenting for surgery with renal dysfunction requiring renal replacement therapy (RRT) is expected to increase as the population ages and improvements in therapy continue to be made. Every aspect of the perioperative period is affected by renal dysfunction, its associated comorbidities, and altered physiology secondary to RRT. Most alarming is the increased risk for perioperative cardiac morbidity and mortality seen in this population. Perioperative optimization and management aims to minimize these risks; however, few definite guidelines on how to do so exist.

Cardiovascular Comorbidities Are the Main Predictors of Cardiac Reverse Remodeling following Kidney Transplantation

BACKGROUND

End-stage renal disease is associated with cardiac remodeling, which is partly reversible after kidney transplantation (KT). We aimed to determine the association of cardiovascular comorbidities or kidney-related factors with cardiac reverse remodeling after KT.

METHODS

We performed echocardiography in 56 patients (aged 48 ± 15 years, mean ± SD) before and 24 months after undergoing their first KT. Echocardiograms were reviewed using a standardized process with blinding for the patient characteristics and evaluation timing. Multivariable linear regression analysis was used to evaluate the association between comorbidities and changes in cardiac structure and systolic/diastolic function.

RESULTS

Left ventricular mass index (LVMI) and diastolic parameters did not change significantly, while left ventricular ejection fraction (LVEF) increased from 63.9 to 69.6% (p = 0.046). Multivariable analysis revealed associations of histories of valvular heart disease with a smaller reduction in LVMI (β = -27.3, p = 0.04), of coronary artery disease or heart failure with a smaller increase in LVEF (β = 7.17, p = 0.02), and of diabetes mellitus with less improvement in E wave (β = -0.19, p = 0.05), e' (β = 4.15, p = 0.046), and E/e' (β = -5.00, p < 0.01).

CONCLUSION

Cardiovascular comorbidities were -associated with less improvement in cardiac structure and function following KT. Our findings suggest that patients with CV comorbidities may experience limited "favorable" reverse cardiac remodeling following KT.

Effectiveness of self-management support in maintenance haemodialysis patients with hypertension: A pilot cluster randomized controlled trial

AIM

Uncontrolled hypertension is an independent risk factor for cardiovascular disease and is the leading cause of mortality in haemodialysis patients. The aim of this study was to examine the effectiveness of self-management support (SMS) for blood pressure (BP) control and health behaviours.

METHODS

We conducted a cluster randomized controlled trial (RCT) in which 90 adult haemodialysis patients were assigned to either an SMS or common intervention (CI) group. The SMS group received an intervention consisting of self-management education and motivational interviewing. The CI group received standard care and routine health education. The primary outcome was the BP monitored before each haemodialysis. Secondary outcomes included salt intake (measured using a balance formula), home BP monitoring (HBPM) (assessed using two self-administered questions), and medication adherence (measured using the Medication-taking Behavior Scale). Data were collected at baseline and at 1, 3 and 6 months post-intervention.

RESULTS

The SMS group showed continuous reductions in systolic BP from baseline: -9.2, -8.7, and -8.4 mmHg at 1, 3 and 6 months after the intervention, respectively (P < 0.01). Compared with the CI group, the SMS group had a greater decrease in systolic BP at 1 month: -5.9 mmHg (P = 0.0388), but no significant difference was found at 3 or 6 months (P > 0.05). SMS patients showed an improvement in health behaviours relative to baseline (less salt intake, more consistent HBPM, and greater medication adherence) (P < 0.05).

CONCLUSIONS

Self-management support obtained short-term success in improving salt restriction, regular performance of HBPM and medication adherence, which led to better BP control.

A need for a paradigm shift in focus: From Kt/Vurea to appropriate removal of sodium (the ignored uremic toxin)

Hemodialysis for chronic renal failure was introduced and developed in Seattle, WA, in the 1960s. Using Kiil dialyzers, weekly dialysis time and frequency were established to be about 30 hours on 3 time weekly dialysis. This dialysis time and frequency was associated with 10% yearly mortality in the United States in 1970s. Later in 1970s, newer and more efficient dialyzers were developed and it was felt that dialysis time could be shortened. An additional incentive to shorten dialysis was felt to be lower cost and higher convenience. Additional support for shortening dialysis time was provided by a randomized prospective trial performed by National Cooperative Dialysis Study (NCDS). This study committed a Type II statistical error rejecting the time of dialysis as an important factor in determining the quality of dialysis. This study also provided the basis for the establishment of the Kt/V_urea index as a measure of dialysis adequacy. This index having been established in a sacrosanct randomized controlled trial (RCT), was readily accepted by the HD community, and led to shorter dialysis, and higher mortality in the United States. Kt/V_urea is a poor measure of dialysis quality because it combines three unrelated variables into a single formula. These variables influence the clinical status of the patient independent of each other. It is impossible to compensate short dialysis duration (t) with the increased clearance of urea (K), because the tolerance of ultrafiltration depends on the plasma-refilling rate, which has nothing in common with urea clearance. Later, another RCT (the HEMO study) committed a Type III statistical error by asking the wrong research question, thus not yielding any valuable results. Fortunately, it did not lead to deterioration of dialysis outcomes in the United States. The third RCT in this field ("in-center hemodialysis 6 times per week versus 3 times per week") did not bring forth any valuable results, but at least confirmed what was already known. The fourth such trial ("The effects of frequent nocturnal home hemodialysis") too did not show any positive results primarily due to significant subject recruitment issues leading to inappropriate selection of patients. Comparison of the value of peritoneal dialysis and HD in RCTs could not be completed because of recruitment problems. Randomized controlled trials have therefore failed to yield any meaningful information in the area of dose and or frequency of hemodialysis.

Hypertension in patients on dialysis: diagnosis, mechanisms, and management

Hypertension (blood pressure > 140/90 mm Hg) is very common in patients undergoing regular dialysis, with a prevalence of 70-80%, and only the minority has adequate blood pressure (BP) control. In contrast to the unclear association of predialytic BP recordings with cardiovascular mortality, prospective studies showed that interdialytic BP, recorded as home BP or by ambulatory blood pressure monitoring in hemodialysis patients, associates more closely with mortality and cardiovascular events. Although BP is measured frequently in the dialysis treatment environment, aspects related to the measurement technique traditionally employed may be unsatisfactory. Several other tools are now available and being used in clinical trials and in clinical practice to evaluate and treat elevated BP in chronic kidney disease (CKD) patients. While we wait for the ongoing review of the CKD Blood Pressure KIDGO guidelines, there is no guideline for the dialysis population addressing this important issue. Thus, the objective of this review is to provide a critical analysis of the information available on the epidemiology, pathogenic mechanisms, and the main pillars involved in the management of blood pressure in stage 5-D CKD, based on current knowledge.

Diabetic nephropathy and hypertension in diabetes patients of sub-Saharan countries: a systematic review and meta-analysis

OBJECTIVE

This meta-analysis was undertaken to estimate the prevalence of diabetic nephropathy and its association with hypertension in diabetics of sub-Saharan African countries.

RESULTS

A total of 27 studies were included for the meta-analysis. The pooled overall prevalence of diabetic nephropathy was 35.3 (95% CI 27.46-43.14). In sub-group analyses by types of diabetes and regions, for instance, the prevalence was 41.4% (95% CI 32.2-50.58%) in type-2 diabetes mellitus and 29.7% (95% CI 14.3-45.1%) in Eastern Africa. Pooled point estimates from included studies revealed an increased risk of diabetic nephropathy with hypertension compared to without hypertension (OR = 1.67, 95% CI 1.31, 2.14). Diabetic nephropathy is a common complication in diabetic patients. Diabetic nephropathy complication is significantly higher in hypertensive patients. A preventive strategy should be adopted or planned to reduce diabetes mellitus and its complication of neuropathy, particularly in hypertensive.

Influence of Carnicor, Venofer, and Sevelamer on the levels of genotoxic damage in end-stage renal disease patients

End-stage renal disease (ESRD) patients present high levels of phosphorus and calcium products in serum, which contribute to the development of vascular calcification and cardiovascular disease, and to low iron stores and carnitine deficiency. For these reasons, ESRD patients are generally supplemented with different medicines. Some of the most common treatments include the use of Carnicor, Venofer, and Sevelamer drugs. Carnicor is used as a source of L-carnitine, acting as antioxidant and neuroprotector. Venofer is used to reduce the deficit of iron. Sevelamer is used to treat hyperphosphatemia. To determine the potential harmful genotoxic effects of these drugs, a group of 214 patients included in a hemodialysis program with different intakes of Carnicor, Venofer, and Sevelamer were evaluated. The levels of basal and oxidative DNA damage, as well as chromosomal damage, were measured in all individuals using the comet and the micronucleus assays, respectively. Our results indicate that Carnicor administration was associated with low but significant increases in the frequency of basal DNA damage and micronuclei. Environ. Mol. Mutagen. 59:302-311, 2018. © 2018 Wiley Periodicals, Inc.

Effect of acute intradialytic aerobic and resistance exercise on one-day blood pressure in patients undergoing hemodialysis: a pilot study

BACKGROUND

Hypertension and intradialytic hypotension are independent risk factors for mortality in hemodialysis patients. We hypothesized that intradialytic exercise would increase blood pressure (BP) during dialysis and decrease it during the postdialytic period. The present study aimed to investigate the effect of acute intradialytic exercise on BP both during dialysis and for 20 hours postdialysis, and to detect any differences in effects of aerobic exercise (AE), resistance exercise (RE), and usual care (UC-the control condition).

METHODS

Eleven patients undergoing maintenance hemodialysis performed two complete sets of AE or RE, with a 1-hour rest between the sets. The patients performed AE, RE and UC over three consecutive weeks at 7-day intervals. Intradialytic BP was measured using an oscillometric BP monitor (N.=11), and ambulatory BP was measured for 20 hours after each dialysis session using an ambulatory BP monitor (N.=8).

RESULTS

The mean BP of the patients in the AE and RE interventions increased during exercise (P<0.05), with the exception of the first set of AE. However, only RE increased BP significantly compared with UC (P<0.05). Following dialysis, daytime ambulatory BP was significantly lower after AE and RE than after UC (P<0.05).

CONCLUSIONS

Acute intradialytic exercise interventions are effective in increasing BP during dialysis and decreasing daytime ambulatory BP after dialysis. Longer observation periods and larger sample sizes will be needed to confirm our findings. Also further studies should be performed on patients prone to intradialytic hypotension.

The Importance of Dialysate Sodium Concentration in Determining Interdialytic Weight Gains in Chronic Hemodialysis Patients: The PanThames Renal Audit

Background and Objectives

There is controversy as to the optimum dialysate sodium to be used for hemodialysis patients, with reports of hypertension and increased interdialytic weight gains with high sodium dialysates and intradialytic hypotension and cramps with low sodium dialysates.

Methods

We analyzed the effect of different dialysate sodium concentrations during a one-week period in an audit of 2187 established patients regularly receiving dialysis three times a week. Patients were given general dietary advice to restrict dietary sodium intake, but no systematic assessment of dietary sodium intake was undertaken.

Results

The prescription of a dialysate sodium concentration of 140 mmol/L and >140 mmol/L, was associated with greater interdialytic weight gains, 3.5% and 4.1% respectively, compared to 2.8% and 2.7% for those using dialysate sodium concentrations of 137 and 136 mmol/L, respectively (p<0.05). The mean pulse pressure was greater patients dialyzing using a sodium of 140 mmol/L, compared to 136 mmol/L, 70 (13) vs 63 (15) mmHg (p<0.011). In addition, 13.5% of patients using the highest sodium dialysate suffered symptomatic intradialytic hypotension requiring intravenous fluid resuscitation, compared to 2.7% who used the lowest sodium concentrate (p<0.05).

Conclusions

This analysis would support the use of lower dialysate sodium concentrations to aid in reducing interdialytic weight gains and subsequent intradialytic hypotension.

Short, Thrice-Weekly Hemodialysis is Inadequate Regardless of Small Molecule Clearance

Chronic hemodialysis sessions, as developed in Seattle in the 1960s, were long procedures with minimal intra- and interdialytic symptoms. Over the next three decades, financial and logistical pressures related to the overwhelming number of patients requiring hemodialysis created an incentive to shorten dialysis time to four, three, and even two hours per session in a thrice weekly schedule. This method spread rapidly, particularly in the United States, after the National Cooperative Dialysis Study suggested that time of dialysis is of minor importance as long as urea clearance multiplied by dialysis time and scaled to total body water (Kt/Vurea) equals 0.95–1.0. This number was later increased to 1.3, but the assumption that hemodialysis time is of minimal importance, as long as it is compensated by increased urea clearance, remained unchanged. Patients accepted short dialysis as a godsend, believing that it would not be detrimental to their well being and longevity.

However, Kt/Vurea measures only removal of low molecular weight substances and does not consider removal of larger molecules. Nor does it correlate with the other important function of hemodialysis, namely ultrafiltration. Whereas patients with substantial residual renal function may tolerate short dialysis sessions, patients with little or no urine output tolerate short dialyses poorly because at a given interdialytic weight gain the ultrafiltration rate is inversely proportional to dialysis time. Rapid ultrafiltration is associated with cramps, nausea, vomiting, headache, fatigue, hypotensive episodes during dialysis, and hangover after dialysis; patients remain fluid overloaded with subsequent poor blood pressure control leading to left ventricular hypertrophy, diastolic dysfunction, and high cardiovascular mortality.

Short, high-efficiency dialysis requires high blood flow, which increases demands on blood access. The classic, wrist arteriovenous fistula, the access with the best longevity and lowest complication rates, provides “insufficient” blood flow and is replaced with an arteriovenous graft fistula or an intravenous catheter. Moreover, to achieve high blood flows, large diameter intravenous catheters are used; these fit veins “too tightly” and so predispose to central-vein thrombosis.

Longer hemodialysis sessions (5–8 hours, thrice weekly), as practiced in some centers, are associated with lower complication rates and better outcomes. Frequent dialyses (four or more sessions per week) with total weekly dialysis time sufficient to allow gentle ultrafiltration rates provide the best clinical results, but are associated with increased costs which are not properly reimbursed in the USA at present. Therefore, it is my strong belief that before a more appropriate reimbursement is available, a wide acceptance of longer, gentler dialysis sessions, in the current thrice weekly schedule, would improve overall hemodialysis results, decrease access complications, hospitalizations and mortality, particularly in anuric patients.

Kt/Vurea should be abandoned as a measure of dialysis quality. The formula suggests that it is possible to decrease t as long as K is proportionately increased, but this is not true. The use of rigid, quantitative guidelines (e.g., spKt/Vurea of 1.3 per dialysis) assumes that all patients behave identically in response to therapeutic maneuvers, like the mean of the group, but this is also not true. The individual, clinical approach assumes that there are differences among patients, which require adjustment of dialysis schedule for each patient.

Hydrochlorothiazide does not increase furosemide's effects in end-stage renal disease

Diuretic therapy for the treatment of edema in patients with end-stage renal disease (ESRD) is unsatisfactory, and a combination of thiazide and loop diuretics may produce better clinical effects. To evaluate the influence of thiazide on loop diuretic therapy for ESRD, we performed a crossover study of furosemide versus hydrochlorothiazide plus furosemide treatment. The diuretic effects of furosemide (160 mg i.v.) alone versus a combination of hydrochlorothiazide (100 mg p.o.) and furosemide were studied in ten ESRD patients with proteinuria greater than 1 g/day. The diuretic effects were compared for 24 h urine volume and electrolyte excretion. To detect the influence of thiazide that may have been obscured in the widely dispersed data, pharmacodynamic analysis of urine furosemide excretion rate versus fractional excretion of sodium (FeNa) was also performed using mixed-effect modeling. Combination therapy was not significantly different from furosemide monotherapy in terms of 24 h urine volume, chloride, or sodium excretion. Hydrochlorothiazide was not a significant covariate in the furosemide effect for the pharmacodynamic model. In patients with ESRD and severe proteinuria (>1,000 mg/day), the combination of hydrochlorothiazide with furosemide therapy did not increase the diuretic effect of furosemide.

Relationship between Hemoglobin Levels Corrected by Interdialytic Weight Gain and Mortality in Japanese Hemodialysis Patients: Miyazaki Dialysis Cohort Study

BACKGROUND

Although hemoglobin (Hb) levels are affected by a change in the body fluid status, the relationship between Hb levels and mortality while taking interdialytic weight gain (IDWG) at blood sampling into account has not yet been examined in hemodialysis patients.

STUDY DESIGN

Cohort study.

SETTING, PARTICIPANTS

Data from the Miyazaki Dialysis cohort study, including 1375 prevalent hemodialysis patients (median age (interquartile range), 69 (60-77) years, 42.3% female).

PREDICTOR

Patients were divided into 5 categories according to baseline Hb levels and two groups based on the median value of IDWG rates at blood sampling at pre-HD on the first dialysis session of the week.

OUTCOMES

All-cause and cardiovascular mortalities during a 3-year follow-up.

MEASUREMENTS

Hazard ratios were estimated using a Cox model for the relationship between Hb categories and mortality, and adjusted for potential confounders such as age, sex, dialysis duration, erythropoiesis-stimulating agent dosage, Kt/V, comorbid conditions, anti-hypertensive drug use, serum albumin, serum C-reactive protein, serum ferritin, and serum intact parathyroid hormone. Patients with Hb levels of 9-9.9 g/dL were set as our reference category.

RESULTS

A total of 246 patients (18%) died of all-cause mortality, including 112 cardiovascular deaths. Lower Hb levels (<9.0g/dL) were associated with all-cause mortality (adjusted HRs 2.043 [95% CI, 1.347-3.009]), while Hb levels were not associated with cardiovascular mortality. When patients were divided into two groups using the median value of IDWG rates (high IDWG, ≥5.4% and low IDWG, <5.4%), the correlation between lower Hb levels and all-cause mortality disappeared in high IDWG patients, but was maintained in low IDWG patients (adjusted HRs 3.058 [95% CI,1.575-5.934]). On the other hand, higher Hb levels (≥12g/dL) were associated with cardiovascular mortality in high IDWG patients (adjusted HRs 2.724 [95% CI, 1.010-7.349]), but not in low IDWG patients.

CONCLUSION

In hemodialysis patients, target Hb levels may need to be selected in consideration of IDWG at blood sampling.

The evaluation of relationship between blood pressure and dialysate Na concentration in chronic hemodialysis patients

Introduction: Hypertension is one of the traditional risk factors of cardiovascular disease (CVD). Extra cellular volume expansion and Na retention remain the main cause of hypertension.

Objectives: The aim of this study was to investigate the relation between concentration of Na dialysate and blood pressure (BP) in chronic hemodialysis (HD) patient.

Patients and Methods: This cross-sectional study was performed on 266 adult patients undergoing HD for at least three months. Pre-HD systolic BP (SBP) and post-HD SBP during 4 weeks were measured in relation to Na dialysate concentration. The other main factors affecting the post-dialysis BP, such as body mass index (BMI), pump speed, dialysis solution temperature, duration of dialysis and intradialysis weight gain (IDWG) were also considered. Mean of ΔSBP (post-HD SBP – pre-HD SBP) in each patient in 12 session of HD was measured and statistically analyzed in relation to dialysate Na with SPSS 21. Backward multivariable linear regression analysis and Pearson’s correlation coefficients were used to evaluate the correlation between sodium gradient and ΔSBP.

Results: SBP was significantly changed before and after dialysis in relation to dialysate Na (P<0.001). The Pearson’s correlation between ΔSBP with dialysate sodium and blood flow rate (pump speed) were statistically significant(P<0.05).

Conclusion: We found that changes in SBP before and after dialysis is significantly associated with dialysate sodium concentration.

Review: Blood pressure in haemodialysis patients: The importance of the relationship between the renin-angiotensin-aldosterone system, salt intake and extracellular volume

This review outlines the major mechanisms for control of blood pressure (BP) in individuals with renal failure on haemodialysis. Dietary salt stimulates thirst and, thereby, greater fluid intake with excessive fluid gain between dialysis sessions and chronic expansion of extracellular volume. At the same time, this volume expansion often fails to suppress the renin-angiotensin system (RAS) appropriately and this inevitably leads to high BP in the majority of individuals on haemodialysis.

A greater understanding of the mechanisms involved leads to more rational treatment and better BP control. This can be achieved by careful measurement of BP before and after dialysis, allowing time for the equilibration of extracellular fluid shifts that occur after dialysis, combined with measurements of plasma renin activity. It is relatively easy to then decide how the high BP should be treated either by removal of excess volume by gradual ultrafiltration combined with restriction of salt intake to help prevent thirst and excessive fluid gain between dialyses, or by inhibition of the RAS, or by a combination of both.

In those individuals who are unable to adequately reduce their dietary salt intake and still continue to gain large amounts of weight between dialysis, and are resistant to reducing their pre-dialysis weight, calcium antagonists may help to lower BP, either alone or in combination with RAS blockade. However, the BP often remains resistant to treatment unless they can be persuaded to reduce their salt intake.

We Hold Antihypertensives Prior To Dialysis

Hypertension is the most common complication of end-stage renal disease and chronic hemodialysis and yet, only a third of these patients have adequately controlled blood pressures. Pathogenesis of hypertension in this population is complex and multifactorial and therefore poses numerous treatment challenges. Furthermore, it is common practice among nephrologists to withhold antihypertensives prior to a hemodialysis procedure due to concerns for intradialytic hypotension (IDH). Intradialytic hypertension (ID-HTN) is an increasingly recognized phenomenon and although less common than IDH, portends poor cardiovascular prognosis as well as reflects higher hypertension burden in the dialysis population. Withholding antihypertensives prior to dialysis routinely in patients may worsen interdialytic blood pressure control as well as increase the prevalence of euvolemic ID-HTN. It may also increase the risk of cardiac arrhythmias and further compromise hemodynamic stability during dialysis. In such situations, predialysis administration of antihypertensive is appropriate and necessary and drug choice should be based on the patient's comorbidities, pharmacokinetics of the drug and its dialyzability.

Some Aspects of the Renin-Angiotensin-System in Hemodialysis Patients

Understanding of the renin-angiotensin system (RAS) has changed remarkably over the past decade. Renin, angiotensin converting enzyme (ACE), angiotensin II (Ang II), and Ang II receptors are the main components of the RAS. Recent studies identified the ACE2/Ang 1–7/ Mas receptor axis, which counter-regulates the classical RAS. Many studies have examined the effects of the RAS on the progression of cardiovascular disease and chronic kidney disease (CKD). In addition, many studies have documented increased levels of ACE in hemodialysis (HD) patients, raising concerns about the negative effects of RAS activation on the progression of renal disease. Elevated ACE increases the level of Ang II, leading to vasoconstriction and cell proliferation. Ang II stimulation of the sympathetic system leads to renal and cardiovascular complications that are secondary to uncontrolled hypertension. This review provides an overview of the RAS, evaluates new research on the role of ACE2 in dialysis, and reviews the evidence for potentially better treatments for patients undergoing HD. Further understanding of the role of ACE and ACE2 in HD patients may aid the development of targeted therapies that slow the progression of CKD and cardiovascular disease.

[Hemodynamic effects of succinate-containing dialyzing solution]

AIM

To assess the results of using an acetate-free succinate-containing dialyzing solution (SDS) against natremia and blood pressure (BP) in patients on chronic hemodialysis (HD).

SUBJECTS AND METHODS

Ninety-two patients were transferred from 3 Saint Petersburg HD centers to 3-month HD treatment using SDS. The investigators measured blood biochemical indicators immediately before and 1 and 3 months after the investigation, BP before and after a successive HD session, and the patients' weight and its gain in the period between HD sessions. Hypotensive and hypertensive episodes were recorded during HD sessions throughout the investigation.

RESULTS

Following 3-month treatment using SDS, there were statistically significant decreases in blood sodium levels and systolic BP (SBP) prior to a HD session. At the same time, patients with a baseline pre-HD SBP of less than 100 mm Hg were observed to have a statistically significant increase in this indicator by the end of the investigation. Pre-dialysis diastolic BP (DBP) and post- dialysis SBP and DBP substantially unchanged. After 3 months of SDS use, there was a statistically significant reduction in weight gain in the period between HD sessions. When SDS was administered, the frequency of hypertensive episodes tended to decline after a HD session.

CONCLUSION

The use of SDS causes a drop in pre-dialysis blood sodium levels, ensuring adequate dehydration in patients and improving hypertension control. In doing so, SDS prevents hypotension during a HD session.

Aerobic training during hemodialysis improves body composition, muscle function, physical performance, and quality of life in chronic kidney disease patients

[Purpose] We assessed the influences of individualized aerobic training on body composition, knee joint muscle function, physical performance, and quality of life in chronic kidney disease patients. [Subjects] Ten chronic kidney disease patients undergoing dialysis. [Methods] Overall physical function and quality of life before and after 12 weeks of aerobic training were evaluated by body composition, the six-minute walk test, cardiopulmonary exercise tests, and Short Form 36-item questionnaire. [Results] The six-minute walk test distance increased significantly after 12 weeks aerobic training. Resting metabolic rate, lactate threshold, maximum oxygen uptake, and quality of life tended to increase after training. Post-training weight, muscle mass, body fat mass, fat percentage, body mass index, and peak torque of right and left knee extension and flexion did not change significantly. [Conclusion] Intra-dialytic training can a safe approach to maintain or improve physical performance and quality of life of chronic kidney disease patients undergoing hemodialysis without adverse events or negative cardiovascular responses. Aerobic training may prevent a decline in body composition and knee joint muscle function due to inactivity in chronic kidney disease patients. Clinically, aerobic training may initially be adapted to maintain overall physical function or improve quality of life in chronic kidney disease patients undergoing hemodialysis.

SELF-REPORTED MEDICATION ADHERENCE IN PATIENTS WITH END-STAGE KIDNEY DISEASE UNDERGOING ONLINE-HAEMODIAFILTRATION

INTRODUCTION

Non-adherence to therapeutic regimens is a recognised problem in the dialysis population that compromises the opportunity to achieve maximum treatment effect and, therefore, might lead to increased morbidity and mortality. In this study, we aimed to evaluate the prevalence of self-reported medication non-adherence in patients with end-stage kidney disease (ESKD) undergoing online-haemodiafiltration (OL-HDF), as well as to evaluate the factors that could affect medication adherence.

PATIENTS AND METHODS

We evaluated 122 patients with ESKD undergoing OL-HDF. Patients' reported medication adherence was measured by the Measure Treatment Adherence (MTS) scale. Social support was evaluated by the abbreviated Lubben Social Network Scale (LSNS); depression status by the Geriatric Depression Scale (GDS). Socio-demographic, co-morbidity and clinical data were also evaluated.

RESULTS

Our results showed that 10.7% of patients with ESKD perceived themselves as non-adherent to medication. When two groups of patients (adherent and non-adherents) were compared, significantly higher levels of triglycerides, and higher diastolic and systolic blood pressure were found in the non-adherent group. Significant correlations were found between the MTS score, and diastolic blood pressure, age and GDS score. Multiple regression analysis identified age and the GDS score as independent variables significantly associated with the MTS score.

CONCLUSIONS

Non-adherence to therapeutic regimens in patients with ESKD is associated with higher levels of triglycerides and higher blood pressure and are, therefore, at a higher cardiovascular risk. Moreover, we found that age and depression status are important variables in non-adherence to therapeutic regimens.

Relationship between different blood pressure measurements and left ventricular mass by cardiac magnetic resonance imaging in end-stage renal disease

Hypertension is prevalent in patients with end-stage renal disease and is strongly associated with left ventricular hypertrophy (LVH), an independent predictor of cardiovascular mortality. Blood pressure (BP) monitoring in hemodialysis patients may be unreliable because of its lability and variability. We compared different methods of BP measurement and their relationship with LVH on cardiac magnetic resonance imaging. Sixty patients undergoing chronic hemodialysis at a single dialysis center had BP recorded at each dialysis session over 12 weeks: pre-dialysis, initial dialysis, nadir during dialysis, and post-dialysis. Forty-five of these patients also underwent 44-hour inter-dialytic ambulatory BP monitoring. Left ventricular mass index (LVMI) was measured using cardiac magnetic resonance imaging and the presence of LVH was ascertained. Receiver operator characteristic curves were generated for each BP measurement for predicting LVH. The mean LVMI was 68 g/m(2) (SD = 15 g/m(2)); 13/60 patients (22%) had LVH. Mean arterial pressure measured shortly after initiation of dialysis session was most strongly correlated with LVMI (Pearson correlation coefficient r = 0.59, P < .0001). LVH was best predicted by post-dialysis systolic BP (area under the curve, 0.83; 95% confidence interval, 0.72-0.94) and initial dialysis systolic BP (area under the curve, 0.81; 95% confidence interval, 0.70-0.92). Forty-four-hour ambulatory BP and BP variability did not significantly predict LVH. Initial dialysis mean arterial pressure and systolic BP and post-dialysis systolic BP are the strongest predictors of LVH, and may represent the potentially best treatment targets in hemodialysis patients to prevent end-organ damage. Further studies are needed to confirm whether treatment targeting these BP measurements can optimize cardiovascular outcomes.

Evidence for the prevention and treatment of stroke in dialysis patients

The risks of both ischemic and hemorrhagic stroke are particularly high in dialysis patients of any age and outcomes are poor. It is therefore important to identify strategies that safely minimize stroke risk in this population. Observational studies have been unable to clarify the relative importance of traditional stroke risk factors such as blood pressure and cholesterol in those on dialysis, and are affected by biases that usually make them an inappropriate source of data on which to base therapeutic decisions. Well-conducted randomized trials are not susceptible to such biases and can reliably investigate the causal nature of the association between a potential risk factor and the outcome of interest. However, dialysis patients have been under-represented in the cardiovascular trials which have proven net benefit of commonly used preventative treatments (e.g., antihypertensive treatments, low-dose aspirin, carotid revascularization, and thromboprophylaxis for atrial fibrillation), and there remains uncertainty about safety and efficacy of many of these treatments in this high-risk population. Moreover, the efficacy of renal-specific therapies that might reduce cardiovascular risk, such as modulators of mineral and bone disorder, online hemodiafiltration, and daily (nocturnal) hemodialysis, have not been tested in adequately powered trials. Recent trials have also demonstrated how widespread current practices could be causing stroke. Therefore, it is important that reliable information on the prevention and treatment of stroke (and other cardiovascular disease) in dialysis patients is generated by performing large-scale randomized trials of many current and future treatments.

Total body water and failure to control blood pressure by medication in hemodialysis patients

Background

Volume overload is the main factor responsible for the pathogenesis of hypertension in dialysis patients. Few studies have evaluated the interpretation of the parameters obtained by bioelectrical impedance (BIA) to manage these patients. The aim of this study was to assess the best cutoff level of volume overload obtained by BIA able to predict the absence of hypertension control in hemodialysis patients.

Methods

Volume overload was calculated as the difference between total body water (TBW) measured by bioimpedance and TBW estimated by the Watson formula in chronic stable hemodialysis patients. Inadequate control of blood pressure (BP) was defined as the mean of measurements obtained before five hemodialysis sessions ≥140 × 90 mm Hg. The best cutoff level of volume overload assessed by BIA able to predict the absence of BP control in patients on chronic hemodialysis was determined by the receiver operating characteristic (ROC) curve using the Youden method.

Results

We included 205 patients, 53% male, aged 56 ± 14.5 years. The largest area under the ROC curve was found for predialysis volume overload (0.660, 95% CI 0.556-0.765, p = 0.004). The ROC curve of postdialysis volume overload also reaches statistical significance. The best cutoff point was found for predialysis volume overload ≥1.4 liters with a sensitivity of 69% and a specificity of 67%.

Conclusion

The association of TBW and inadequate BP control highlights the importance of volume management in hemodialysis patients. Predialysis volume overload of 1.4 liters was the parameter that best discriminated the presence of inadequate BP control.

Short daily versus conventional hemodialysis for hypertensive patients: a randomized cross-over study

Background

Treatment of end stage renal disease patients with short daily hemodialysis has been associated with an improvement in blood pressure. It is unclear from these studies if anti-hypertensive management had been optimized prior to starting short daily hemodialysis. Also, the potential mechanism(s) of blood pressure improvement remain to be fully elucidated.

Study Design, Setting and Participants

We undertook a randomized cross-over trial in adult hypertensive patients with ESRD treated with conventional hemodialysis to determine: 1) if short-daily hemodialysis is associated with a reduction in systolic blood pressure after a 3-month blood pressure optimization period and; 2) the potential mechanism(s) of blood pressure reduction. Blood pressure was measured using Canadian Hypertension Education Program guidelines. Extracellular fluid volume (ECFV) was assessed with bioimpedance. Serum catecholamines were used to assess the sympathetic nervous system. Interleukin-6 (IL-6) and thiobarbituric acid reactive substances (T-BARS) were used as markers of inflammation and oxidative stress respectively.

Results

After a 3-month run-in phase in which systolic blood pressure improved, there was no significant difference in pre-dialysis systolic pressure between short-daily and conventional hemodialysis (p = 0.39). However, similar blood pressures were achieved on fewer anti-hypertensive medications with short daily hemodialysis compared to conventional hemodialysis (p = 0.01). Short daily hemodialysis, compared to conventional hemodialysis, was not associated with a difference in dry weight or ECFV (p = 0.77). Sympathetic nervous system activity as assessed by plasma epinephrine (p = 1.0) and norepinephrine (p = 0.52) was also not different. Markers of inflammation (p = 0.42) and oxidative stress (p = 0.83) were also similar between the two treatment arms.

Conclusions

Patients treated with short daily, compared to conventional hemodialysis, have similar blood pressure control on fewer anti-hypertensive medications. The mechanism(s) by which short daily hemodialysis allows for decreased anti-hypertensive medication use remains unclear but effects on sodium balance and changes in peripheral vascular resistance require further study.

Trial Registration

ClinicalTrials.gov NCT00759967

Significance of white-coat and masked hypertension in chronic kidney disease and end-stage renal disease

Hypertension is a frequent and modifiable cardiovascular risk factor with a cyclic relationship with chronic kidney disease (CKD). The diagnosis, treatment, monitoring and control of high blood pressure are all mandatory not only in CKD but also in end-stage renal disease (ESRD). As demonstrated by studies using population and hypertensive patients, white-coat hypertension (WCHT) and masked hypertension (MHT) carry a particular degree of risk. The advantages of ambulatory techniques in the management and prognostic stratification of patients with CKD and ESRD have also been recognized. However, most of the evidence underlines the importance of nocturnal hypertension and neglects WCHT and MHT. The absence of specific reports involving untreated and treated patients hinders the ability to significantly discriminate WCHT from the white-coat effect and MHT from masked uncontrolled hypertension. The heterogeneous definitions that are used add additional difficulty in translating experimental evidence into clinical practice. Reaching a consensus in definitions is mandatory for designing future research. Cross-sectional studies underscore the frequency of misdiagnosis, potentially leading to undertreatment (MHT) and overtreatment (WCHT) in renal disease. The divergent prevalence of WCHT and MHT reported in CKD could be related to the diverse definitions of hypertension and the heterogeneity of the pathologies pooled under the CKD definition. Even in the absence of randomized clinical trials specifically addressing this issue, the scarce longitudinal studies confirm that WCHT carries a risk close to that of sustained normotension, whereas MHT is associated with a risk close or identical to that of sustained hypertension.

Postdialysis serum sodium changes and systolic blood pressure in patients undergoing online hemodiafiltration and high-flux hemodialysis

Background

Because hemodiafiltration (HDF) involves large amounts of ultra-filtration and substitution fluid infusion, its effects on serum electrolytes may be different from those of hemodialysis (HD). Serum sodium and blood pressures were compared between patients undergoing online HDF and high-flux HD (HFHD).

Methods

Thirty-two of 101 patients on HFHD switched voluntarily to online HDF. Their pre- and postdialysis serum measurements were compared with those of the remaining 69 HFHD patients.

Results

Online HDF patients had lower pre- and postdialysis systolic blood pressures (SBPs) than HFHD patients (predialysis, 136±21 vs. 145±19 mmHg, P<0.05; postdialysis, 129±22 vs. 142±25 mmHg, P<0.05). Pre- and postdialysis serum sodium concentrations were not significantly different between online HDF and HFHD (predialysis, 138±2 vs. 137±3 mEq/L; postdialysis, 134±2 vs. 134±2 mEq/L). However, the change in serum sodium concentration after dialysis was greater in online HDF than HFHD patients (−3.7±2.2 vs. −2.5±2.8 mEq/L, P<0.05). The change in serum sodium concentration was correlated with postdialysis SBP (r=0.304, P<0.005) and pulse pressure (r=0.299, P<0.005). Predialysis SBP (r = 0.317, P<0.005) and pulse pressure (r=0.324, P=0.001) were also correlated with the postdialysis serum sodium change.

Conclusion

Compared with HFHD, online HDF has a greater serum sodium lowering effect. This might contribute to the ability of online HDF to stabilize both pre- and postdialysis SBP.

Clinical audit improves hypertension control in hemodialysis patients

BACKGROUND

In patients on hemodialysis (HD), hypertension is a risk factor for cardiovascular disease. In this study we tested the effectiveness of a clinical audit in improving blood pressure (BP) control in HD patients. 


METHODS

177 adult, prevalent patients undergoing dialysis in NephroCare centers in Italy were audited. At the conclusion of the audit, individual strategies were developed in order to improve BP control. Patient data was collected and examined at months -1 (Pre), 0 (the date of the audit- Audit), and +1 and +6 after the audit (Post-1 and Post-6, respectively).
We recorded BP, information on factors affecting BP, and anti-hypertensive drug regimen. The primary outcome of the study was to decrease prevalence of hypertension (BP ≥ 140/90 mmHg). Secondary outcomes were a reduction in average BP in hypertensive patients and/or a decrease in drug delivery associated with lower or unchanged BP.


RESULTS

104 patients out of 177 (58.7%) were hypertensive at Audit. BP levels were directly related to comorbidity and male sex, and inversely related to dialysate sodium concentration. The announcement of the audit alone was associated with a decreased prevalence of hypertension (Pre 64.4% to Audit 58.7%); a further decrease followed the audit (Post-1 51.1%, Post-6 47.6%, p<0.05 vs. Audit). Systolic BP in hypertensive patients also decreased (mean decrease was -8.5 and -14.1; p = 0.007 and p<0.001 at Post-1 and Post-6). Number of drugs assumed was significantly lower at Post-1 and Post-6 vs. Audit (p = 0.005 and p<0.001, respectively).


CONCLUSIONS

A clinical audit is an effective tool to improve BP control in HD patients.