Hypertension in the ESRD patient: pathophysiology, therapy, outcomes, and future directions

Multiparameter neuroimaging study of neurovascular coupling changes in patients with end-stage renal disease

PURPOSE

To assess changes in neurovascular coupling (NVC) by evaluating the relationship between cerebral perfusion and brain connectivity in patients with end-stage renal disease (ESRD) undergoing hemodialysis versus in healthy control participants. And by exploring brain regions with abnormal NVC associated with cognitive deficits in patients, we aim to provide new insights into potential preventive and therapeutic interventions.

MATERIALS AND METHODS

A total of 45 patients and 40 matched healthy controls were prospectively enrolled in our study. Montreal Cognitive Assessment (MoCA) was used to assess cognitive function. Arterial spin labeling (ASL) was used to calculate cerebral blood flow (CBF), and graph theory-based analysis of results from resting-state functional magnetic resonance imaging (rs-fMRI) was used to calculate brain network topological parameters (node betweenness centrality [BC], node efficiency [Ne], and node degree centrality [DC]). Three NVC biomarkers (CBF-BC, CBF-Ne, and CBF-DC coefficients) at the whole brain level and 3 NVC biomarkers (CBF/BC, CBF/Ne, and CBF/DC ratios) at the local brain region level were used to assess NVC. Mann-Whitney U tests were used to compare the intergroup differences in NVC parameters. Spearman's correlation analysis was used to evaluate the relationship among NVC dysfunctional pattern, cognitive impairment, and clinical characteristics multiple comparisons were corrected using a voxel-wise false-discovery rate (FDR) method (p < .05).

RESULTS

Patients showed significantly reduced global coupling coefficients for CBF-Ne (p = .023) and CBF-BC (p = .035) compared to healthy controls. Coupling ratios at the local brain region level were significantly higher in patients in 33 brain regions (all p values < .05). Coupling ratio changes alone or accompanied by changes in CBF, node properties, or both CBF and node properties were identified. In patients, negative correlations were seen between coupling ratios and MoCA scores in many brain regions, including the left dorsolateral superior frontal gyrus, the bilateral median cingulate and paracingulate gyri, and the right superior parietal gyrus. The correlations remained even after adjusting for hemoglobin and hematocrit levels.

CONCLUSION

Disrupted NVC may be one mechanism underlying cognitive impairment in dialysis patients.

α-Blocker Use in Hemodialysis: The Japan Dialysis Outcomes and Practice Patterns Study

Rationale & Objective

Despite α-blockers' use for hypertension as add-on therapy in patients treated with hemodialysis, scant information is available on their association, particularly with safety, in these patients.

Study Design

Prospective cohort study.

Setting & Participants

patients treated with hemodialysis and receiving antihypertensive agents in the Japan Dialysis Outcomes and Practice Patterns Study, phases 4-6, were analyzed.

Exposure

Primary exposure was the prescription of α-blocking antihypertensive agents at baseline.

Outcomes

Incident fractures, falls, and all-cause mortality.

Analytical Approach

Multivariable Cox and modified Poisson regression analysis.

Results

Of 5,149 patients treated with hemodialysis (mean age, 65 years; 68% men) receiving antihypertensive drugs, 717 (14%) received α-blocking agents. During a mean follow-up period of 2.0 years, 247 fractures, 525 falls, and 498 deaths occurred. Multivariable analysis showed no significant association of α-blocker use and increased risk of fractures (hazard ratio [HR], 0.92 [95% confidence interval {CI}, 0.61-1.38]), falls (HR, 0.94 [95% CI, 0.74-1.20]), or all-cause deaths (HR, 0.87 [95% CI, 0.64-1.20]) compared with α-blocker nonuse. α-Blocker use was, however, significantly associated with a decreased risk of all-cause mortality in the subgroup analysis, for example, patients who were older (HR, 0.71 [95% CI, 0.51-0.99]), were women (HR, 0.68 [95% CI, 0.48-0.95]), or reported a history of cardiovascular disease (HR, 0.67 [95% CI, 0.48-0.95]) or a predialysis blood pressure of ≥140 mm Hg (HR, 0.69 [95% CI, 0.49-0.98]).

Limitations

Selection bias cannot be ruled out given the prevalent user analysis.

Conclusions

No significant association between α-blocker use and the risk of worse safety-related outcomes was seen, indicating that clinicians may safely prescribe α-blockers to patients receiving hemodialysis who require blood pressure lowering.

Plain-Language Summary

α-Blockers have been generally reserved for use as add-on therapy for resistant or refractory hypertension. However, little is known about the safety of α-blockers in patients treated by hemodialysis. We analyzed 5,149 patients receiving hemodialysis in Japan who were receiving antihypertensive drugs from the Japan Dialysis Outcomes and Practice Patterns Study. The results showed no significant increase in the risk of fractures, falls, or deaths for patients using α-blockers compared with those who did not, suggesting that α-blockers may be safely prescribed for patients receiving hemodialysis who need to lower their blood pressure.

Long-term peridialytic blood pressure changes are related to mortality

BACKGROUND

In chronic haemodialysis (HD) patients, the relationship between long-term peridialytic blood pressure (BP) changes and mortality has not been investigated.

METHODS

To evaluate whether long-term changes in peridialytic BP are related to mortality and whether treatment with HD or haemodiafiltration (HDF) differs in this respect, the combined individual participant data of three randomized controlled trials comparing HD with HDF were used. Time-varying Cox regression and joint models were applied.

RESULTS

During a median follow-up of 2.94 years, 609 of 2011 patients died. As for pre-dialytic systolic BP (pre-SBP), a severe decline (≥21 mmHg) in the preceding 6 months was independently related to increased mortality [hazard ratio (HR) 1.61, P = .01] when compared with a moderate increase. Likewise, a severe decline in post-dialytic diastolic BP (DBP) was associated with increased mortality (adjusted HR 1.96, P < .0005). In contrast, joint models showed that every 5-mmHg increase in pre-SBP and post-DBP during total follow-up was related to reduced mortality (adjusted HR 0.97, P = .01 and 0.94, P = .03, respectively). No interaction was observed between BP changes and treatment modality.

CONCLUSION

Severe declines in pre-SBP and post-DBP in the preceding 6 months were independently related to mortality. Therefore peridialytic BP values should be interpreted in the context of their changes and not solely as an absolute value.

Burden of Hypertensive Crisis in Patients With End-Stage Kidney Disease on Maintenance Dialysis: Insights From United States Renal Data System Database

BACKGROUND

There is paucity of information on the incidence, clinical characteristics, admission trends, and outcomes of hypertensive crisis (HTN-C) in patients with end-stage kidney disease (ESKD) who are on maintenance dialysis.

METHODS

We conducted a retrospective observational study of HTN-C admissions in patients with end-stage kidney disease using the United States Renal Data System. We identified patients with end-stage kidney disease aged ≥18 years on dialysis and were hospitalized for HTN-C from January 2006 to August 2015.

RESULTS

A total of 54 483 patients with end-stage kidney disease were hospitalized for HTN-C during the study period. After study exclusions, 37 214 patients were included in the analysis. A majority of patients were Black, there were more women than men and the South region of the country accounted for a great majority of patients. During the study period, hospitalization rates increased from 1060 per 100 000 beneficiary years to 1821 (P_trend<0.0001). Overall, in-hospital mortality, 30-day, and 1-year mortality were 0.6%, 2.3%, and 21.8%, respectively, and 30-day readmission rate was 31.1%. During the study period, most study outcomes showed a significant decreasing trend (in-hospital mortality 0.6%-0.5%, 30-day mortality 2.4%-1.9%, 1-year mortality 23.9%-19.7%, P_trend<0.0001 for all).

CONCLUSIONS

Hospitalizations for HTN-C have increased consistently during the decade studied. Although temporal trends showed improving mortality and readmission rates, the absolute rates were still high with 1 in 3 patients readmitted within 30 days and 1 in 5 patients dying within 1 year of index hospitalization.

3D Echocardiography - A Useful Method for Cardiovascular Risk Assessment in End-Stage Renal Disease Patients

Patients with chronic kidney disease (CKD) have an increased risk of premature mortality, mainly due to cardiovascular causes. The association between hemodialysis and accelerated atherosclerosis has long been described. The ankle-brachial index (ABI) is a surrogate marker of atherosclerosis and recent studies indicate its utility as a predictor of future cardiovascular disease and all-cause mortality. The clinical implications of ABI cut-points are not well defined in patients with CKD. Echocardiography is the most widely used imaging method for cardiac evaluation. Structural and functional myocardial abnormalities are common in patients with CKD due to pressure and volume overload as well as non-hemodynamic factors associated with CKD. Our study aimed to identify markers of subclinical cardiovascular risk assessed using ABI and 2D and 3D echocardiographic parameters evaluating left ventricular (LV) structure and function in patients with end-stage renal disease (ESRD) (patients undergoing dialysis), patients after kidney transplantation and non-ESRD patients (control). In ESRD, particularly in hemodialysis patients, changes in cardiac structure, rather than function, seems to be more pronounced. 3D echocardiography appears to be more sensitive than 2D echocardiography in the assessment of myocardial structure and function in CKD patients. Particularly 3D derived end-diastolic volume and 3D derived LV mass indexed for body surface appears to deteriorate in dialyzed and transplanted patients. In 2D echocardiography, myocardial mass represented by left ventricular mass/body surface area index (LVMI) appears to be a more sensitive marker of cardiac structural changes, compared to relative wall thickness (RWT), left ventricle and diastolic diameter index (LVEDDI) and left atrial volume index (LAVI). We observed a generally favorable impact of kidney transplantation on cardiac structure and function; however, the differences were non-significant. The improvement seems to be more pronounced in cardiac function parameters, peak early diastolic velocity/average peak early diastolic velocity of mitral valve annulus (E/e´), 3D left ventricle ejection fraction (LV EF) and global longitudinal strain (GLS). We conclude that ABI is not an appropriate screening test to determine the cardiovascular risk in patients with ESRD.

Decreased cerebral blood flow and improved cognitive function in patients with end-stage renal disease after peritoneal dialysis: An arterial spin-labelling study

OBJECTIVES

The aim of this study was to evaluate the relationship between cognitive impairment and brain perfusion using arterial spin labelling (ASL) in end-stage renal disease (ESRD) patients undergoing PD.

METHODS

ESRD patients undergoing PD were recruited. Laboratory screening, neuropsychological tests and ASL magnetic resonance imaging (MRI) were conducted prior to and after 6 months of PD. Age- and sex-matched normal subjects without ESRD served as the control group. Comparisons of regional CBF between ESRD patients before or after undergoing PD and normal controls were performed. Correlations between biochemical, neuropsychological and CBF data were also conducted to evaluate the relationships.

RESULTS

ESRD patients showed poor performance in many of the neuropsychological tests; PD improved cognition in some domains. Pre-PD patients had higher mean CBF than post-PD patients and normal controls, but no significant difference was found between the normal controls and post-PD patients. Negative correlations were observed pre-PD (regional CBF in left hippocampus vs. perseverative responses, r = -0.662, p = 0.014), post-PD (mean CBF vs. haemoglobin level, r = -0.766, p = 0.002), and before and after PD (change in CBF in the left putamen vs. change in haematocrit percentage, r = -0.808, p = 0.001).

CONCLUSION

Before PD, ESRD patients had increased cerebral perfusion that was related to poorer executive function, especially in the left hippocampus. Post-PD patients performed better in some cognitive test domains than pre-PD patients. The degree of anaemia, i.e., haemoglobin level or haematocrit percentage, might predict cognitive impairment in PD patients.

KEY POINTS

• In this study, ESRD patients before PD had cerebral hyperperfusion that was related to poorer executive function. • Post-PD patients performed better in some cognitive test domains than pre-PD patients did. • The degree of anaemia might predict cognitive impairment in PD patients.

Safety and Efficacy of Losartan 50 mg in Reducing Blood Pressure among Patients with Post-Dialysis Euvolemic Hypertension: A Randomized Control Trial

The aim of current study was to assess the effectiveness of losartan 50 mg in reducing blood pressure among post-dialysis euvolemic hypertensive patients, observing their survival trends and adverse events during the course of study. A multicentre, prospective, randomised, single-blind trial was conducted to assess the effect of losartan 50 mg every other day (EOD), once a morning (OM) among post-dialysis euvolemic hypertensive patients. Post-dialysis euvolemic assessment was done by a body composition monitor (BCM). Covariate Adaptive Randomization was used for allocation of participants to the standard or intervention arm. Of the total 229 patients, 96 (41.9%) were identified as post-dialysis euvolemic hypertensive. Final samples of 88 (40.1%) patients were randomized into standard and intervention arms. After follow-up of 12 months’ pre-dialysis systolic (p < 0.001) and diastolic (p 0.01), intradialysis diastolic (p 0.02), post-dialysis systolic (p < 0.001) and diastolic (p < 0.001) blood pressure was reduced from the baseline among intervention-arm patients Compared to only pre-dialysis systolic blood pressure (p 0.003) among standard arm patients after 12 months of follow. Total of six deaths were reported among standard-arm patients compared to 2 deaths among the intervention arm. Losartan 50 mg achieve an overall significant decline in blood pressure among post-dialysis euvolemic hypertensive patients.

Maintenance of negative fluid balance can improve endothelial and cardiac functions in primary hypertensive patients

PURPOSE

The issue of unidentified volume expansion is well recognized as a cause for resistance to antihypertensive therapy. The aim of study is to identify contribution of negative fluid balance to hypertension control and impact on endothelial and cardiac functions among primary hypertensive patients who do not have kidney failure.

MATERIALS AND METHODS

This is a prospective interventional study with one-year follow-up. Preceded by volume status measurements were performed by a body composition monitor (BCM), the patients were put on ambulatory blood pressure monitoring for 24 hours. Then, echocardiographic assessments and flow-mediated dilation (FMD) and carotid intima-media thickness (CIMT) measurements were completed. Patients in one of the two groups were kept negative hydrated during trial with diuretic treatment.

RESULTS

At the end of one-year follow-up, patients in negative hydrated group were found to have significantly lower CIMT, left ventricle mass index, left ventricular end-diastolic diameter, mean systolic and diastolic BP, non-dipper patient ratio, and higher FMD. In negatively hydrated group, target organ damage significantly reduced during trial.

CONCLUSIONS

The significance of negative hydration status with respect to blood pressure control, endothelial and cardiac functions within primary hypertensive patients who do not suffer from kidney failure has been demonstrated.

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.

Nitric Oxide Resistance Reduces Arteriovenous Fistula Maturation in Chronic Kidney Disease in Rats

Background

Autologous arteriovenous (AV) fistulas are the first choice for vascular access but have a high risk of non-maturation due to insufficient vessel adaptation, a process dependent on nitric oxide (NO)-signaling. Chronic kidney disease (CKD) is associated with oxidative stress that can disturb NO-signaling. Here, we evaluated the influence of CKD on AV fistula maturation and NO-signaling.

Methods

CKD was established in rats by a 5/6^th nephrectomy and after 6 weeks, an AV fistula was created between the carotid artery and jugular vein, which was followed up at 3 weeks with ultrasound and flow assessments. Vessel wall histology was assessed afterwards and vasoreactivity of carotid arteries was studied in a wire myograph. The soluble guanylate cyclase (sGC) activator BAY 60–2770 was administered daily to CKD animals for 3 weeks to enhance fistula maturation.

Results

CKD animals showed lower flow rates, smaller fistula diameters and increased oxidative stress levels in the vessel wall. Endothelium-dependent relaxation was comparable but vasorelaxation after sodium nitroprusside was diminished in CKD vessels, indicating NO resistance of the NO-receptor sGC. This was confirmed by stimulation with BAY 60–2770 resulting in increased vasorelaxation in CKD vessels. Oral administration of BAY 60–2770 to CKD animals induced larger fistula diameters, however; flow was not significantly different from vehicle-treated CKD animals.

Conclusions

CKD induces oxidative stress resulting in NO resistance that can hamper AV fistula maturation. sGC activators like BAY 60–2770 could offer therapeutic potential to increase AV fistula maturation.

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.

Dialysate sodium prescription and blood pressure in hemodialysis patients

BACKGROUND

Diffusive sodium removal has been recommended to control hypertension in hemodialysis patients. Recent evidence on hospitalizations and mortality, however, challenged the benefit of lower dialysate sodium prescriptions and ignited a debate in the dialysis community. We therefore studied the relationship between dialysate sodium and blood pressure over the longer term.

METHODS

We used multiply adjusted linear mixed models to estimate the association between dialysate sodium and predialysis systolic blood pressure (SBP) as well as change in SBP (delta SBP; postdialysis minus predialysis) in 23,962 patients from the international Dialysis Outcomes and Practice Patterns Study.

RESULTS

We found that 43% of hemodialysis facilities had variable (individualized) dialysate sodium prescriptions (125-155 mEq/L), whereas 57% had uniform dialysate sodium prescriptions (135-145 mEq/L) for ≥90% patients. Between-group comparisons of these 2 facility types suggested that dialysate sodium, when variably prescribed, might have been used to modify predialysis SBP (P interaction = 0.01) and perhaps delta SBP levels (P interaction = 0.08). Within facilities not prone to indication bias, because dialysate sodium was not variable, higher uniform dialysate sodium (per 2 mEq/L) was associated with slightly higher SBP (+0.9 mm Hg, 95% confidence interval (CI) = 0.1-1.6 among all patients; +1.7 mm Hg, 95% CI = 0.1-3.2 among patients not treated with blood pressure medication) and no increase in delta SBP.

CONCLUSIONS

Patients assigned to hemodialysis facilities with uniformly higher dialysate sodium do not have markedly higher predialysis SBP, providing rather limited support for lowering dialysate sodium to control hypertension, particularly in view of hospitalization and mortality risks associated with lower dialysate sodium.

Non invasive evaluation of cardiac hemodynamics in end stage renal disease (ESRD)

OBJECTIVE

Volume overload is typical of haemodialysis patients; correct volume status evaluation is crucial in achieving blood pressure homeostasis, hypertension management and good treatment planning. This study evaluates the effect of acute volume depletion on ultrasonographic parameters and suggests two of them as able to predict patients volume overload.

PATIENTS AND INTERVENTION

27 patients with end stage renal disease treated with haemodialysis underwent a complete echocardiographic exam before, after 90 min and at the end of the dialysis.

MAIN OUTCOME AND RESULTS

Blood pressure levels significantly drop during the first 90 min of dialysis (139 ± 20 vs 126 ± 18; p < 0.0001), reaching a steady state with significantly lower values compared to baseline (130 ± 28; p = 0.02). LV and left atrial volume significantly decreased (baseline vs end dialysis 98 ± 32 vs 82 ± 31 p = 0.003 and 28 ± 10 vs. 21 ± 9 cc/m(2) p < 0.001). A significant reduction of systolic function (EF 61.6 % ± 9 vs 58.7 % ± 9 p = 0.04), of diastolic flow velocities (E/A 1.13 ± 0.37 vs. 0.87 ± 0.38 p < 0.001) and mitral annulus TDI tissue velocity (i.e. E' lat 10.6 ± 3 vs. 9.4 ± 3 cm/s; p 0.0001) were observed. Stroke work (SW) and LV end-diastolic diameter (LVEDd) indexed to height 2.7(LVEDdi) were able to predict volume overload: cut off values of respectively 13.5 mm/m(2.7) for LVEDdi and 173 cJ for SW were able to predict with a specificity of 100 % the presence of a volemic overload of at least 4 %.

CONCLUSIONS

Blood pressure, cardiac morphology and function are significantly modified by acute volume depletion and such variations are strictly interrelated. SW and LVEDd/height(2.7) may identify ESRD patients carrying an higher volume load.

The assessment of oxidative stress on patients with chronic renal failure at different stages and on dialysis patients receiving different hypertensive treatment

The aim of this study is to evaluate the oxidative stress in predialysis, hemodialysis (HD) and peritoneal dialysis patients and to test the effects of antihypertensive drugs and volume control on oxidative stress parameters. The study was composed of five groups as follows: control group (n = 30), predialysis group (n = 30), peritoneal dialysis group (n = 30), hemodialysis group, (normotensive with strict volume control, n = 30), hemodialysis group (normotensive with medication, n = 30). Plasma malondialdehyde (MDA), erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx) and routine biochemical parameters were studied in all patients. Hemodialysis patients with strict volume control (HDvc) had lower levels of MDA than other patient groups (p < 0.001), and CAT, SOD values had highest level other patient groups (p < 0.001). The treatment of hypertension with strict volume control in chronic renal failure patients causes less damage to the antioxidant capacity.

Pharmacokinetics of aliskiren in patients with end-stage renal disease undergoing haemodialysis

BACKGROUND AND OBJECTIVES

Aliskiren represents a novel class of orally active renin inhibitors. This study analyses the pharmacokinetics, tolerability and safety of single-dose aliskiren inpatients with end-stage renal disease (ESRD) undergoing haemodialysis.

METHODS

Six ESRD patients and six matched healthy volunteers were enrolled in an open-label, parallel-group, single-sequence study. The ESRD patients underwent two treatment periods where 300 mg of aliskiren was administered 48 or 1 h before a standardized haemodialysis session (4 h, 1.4 m(2) high-flux filter, blood flow 300 mL/min, dialysate flow 500 mL/min). Washout was >10 days between both periods. Blood and dialysis samples were taken for up to 96 h postdose to determine aliskiren concentrations.

RESULTS

Compared with the healthy subjects (1681 ± 1034 ng·h/mL), the area under the plasma concentration-time curve (AUC) from time zero to infinity was 61% (haemodialysis at 48 h) and 41% (haemodialysis at 1 h) higher in ESRD patients receiving single-dose aliskiren 300 mg. The maximum (peak) plasma drug concentration (481 ± 497 ng/mL in healthy subjects) was 17% higher (haemodialysis at 48 h) and 16% lower (haemodialysis at 1 h). In both treatment periods, dialysis clearance was below 2% of oral clearance and the mean fraction eliminated from circulation was 10 and 12% in period 1 and 2, respectively. Drug AUCs were similar in ESRD patients receiving aliskiren 1 or 48 h before dialysis. No severe adverse events occurred.

CONCLUSION

The exposure of aliskiren is moderately higher in ESRD patients. Only a minor portion is removed by a typical haemodialysis session. Aliskiren exposure is not significantly affected by intermittent haemodialysis, suggesting that no dose adjustment is necessary in this population.

Associations between coronary calcification on chest radiographs and mortality in hemodialysis patients

BACKGROUND

KDIGO (Kidney Disease: Improving Global Outcomes) guidelines recommend lateral abdominal radiographs to assess vascular calcification in incident dialysis patients. However, nearly all dialysis patients in the United States receive chest radiographs at dialysis therapy inception, which may provide readily available information on coronary artery (CAC) and aortic arch calcification (AAC). We determined the prevalence of CAC and AAC visible on plain chest radiographs and their associations with mortality in our dialysis population.

STUDY DESIGN

Retrospective analysis.

SETTING & PARTICIPANTS

93 participants who received maintenance hemodialysis at the San Diego Veterans Affairs Medical Center in 2009-2010.

PREDICTOR

Presence of CAC and AAC as evaluated by a radiologist.

OUTCOME

All-cause mortality.

RESULTS

Average age was 64 years, 22% were African American, and 97% were men. CAC and AAC prevalences were 25% and 58%, respectively. During 20 months' follow-up, 28% died. CAC was associated with mortality in models including cardiovascular (HR, 2.41; 95% CI, 1.04-5.59) and dialysis-related (HR, 2.86; 95% CI, 1.24-6.60) risk factors. AAC was associated with HRs of 5.25 (95% CI, 1.46-17.72) in cardiovascular risk factor-adjusted models and 7.31 (95% CI, 2.03-26.34) in dialysis models. When CAC and AAC were both included in models, both CAC (HR, 3.40; 95% CI, 1.24-9.36) and AAC (HR, 6.23; 95% CI, 1.64-23.66) remained significantly associated with mortality.

LIMITATIONS

The study sample is relatively small and mostly male.

CONCLUSIONS

CAC and AAC are highly prevalent on chest radiographs in dialysis patients and strongly associated with mortality independent of one another. Because these images are nearly ubiquitous, inexpensive, and often obtained for other indications, they should be considered for risk assessment in hemodialysis patients. Future studies are required to determine whether CAC or AAC on chest radiography is additive or duplicative of the risk of aorto-iliac calcification on lateral abdominal radiographs currently suggested by KDIGO.

Blood volume-monitored regulation of ultrafiltration in fluid-overloaded hemodialysis patients: study protocol for a randomized controlled trial

BACKGROUND

Data generated with the body composition monitor (BCM, Fresenius) show, based on bioimpedance technology, that chronic fluid overload in hemodialysis patients is associated with poor survival. However, removing excess fluid by lowering dry weight can be accompanied by intradialytic and postdialytic complications. Here, we aim at testing the hypothesis that, in comparison to conventional hemodialysis, blood volume-monitored regulation of ultrafiltration and dialysate conductivity (UCR) and/or regulation of ultrafiltration and temperature (UTR) will decrease complications when ultrafiltration volumes are systematically increased in fluid-overloaded hemodialysis patients.

METHODS/DESIGN

BCM measurements yield results on fluid overload (in liters), relative to extracellular water (ECW). In this prospective, multicenter, triple-arm, parallel-group, crossover, randomized, controlled clinical trial, we use BCM measurements, routinely introduced in our three maintenance hemodialysis centers shortly prior to the start of the study, to recruit sixty hemodialysis patients with fluid overload (defined as ≥15% ECW). Patients are randomized 1:1:1 into UCR, UTR and conventional hemodialysis groups. BCM-determined, 'final' dry weight is set to normohydration weight -7% of ECW postdialysis, and reached by reducing the previous dry weight, in steps of 0.1 kg per 10 kg body weight, during 12 hemodialysis sessions (one study phase). In case of intradialytic complications, dry weight reduction is decreased, according to a prespecified algorithm. A comparison of intra- and post-dialytic complications among study groups constitutes the primary endpoint. In addition, we will assess relative weight reduction, changes in residual renal function, quality of life measures, and predialysis levels of various laboratory parameters including C-reactive protein, troponin T, and N-terminal pro-B-type natriuretic peptide, before and after the first study phase (secondary outcome parameters).

DISCUSSION

Patients are not requested to revert to their initial degree of fluid overload after each study phase. Therefore, the crossover design of the present study merely serves the purpose of secondary endpoint evaluation, for example to determine patient choice of treatment modality. Previous studies on blood volume monitoring have yielded inconsistent results. Since we include only patients with BCM-determined fluid overload, we expect a benefit for all study participants, due to strict fluid management, which decreases the mortality risk of hemodialysis patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01416753.

Cardioprotective effect of renalase in 5/6 nephrectomized rats

Cardiovascular disease (CVD) remains one of the most common causes of morbidity and mortality in patients with chronic renal disease. It has been recently postulated that the loss or reduced levels of renalase in patients with chronic renal disease are, at least in part, responsible for elevated plasma catecholamine levels, which leads to increased CVD. Therefore, the aim of the present study was to evaluate whether renalase administration might serve as a therapeutic drug, decreasing the severity of CVD in 5/6 nephrectomized (Nx) rats. The current study was conducted on 30 male Wistar albino rats divided into the following groups: group I: sham-operated rats that received phosphate-buffered saline (PBS) subcutaneously (s.c.) for 4 weeks following sham operation, group II: rats in which 5/6 Nx was done and then the rats received PBS daily s.c. for 4 weeks following 5/6 Nx, and group III: rats in which 5/6 Nx was done and then the rats received recombinant renalase daily s.c. for 4 weeks following 5/6 Nx. 5/6 nephrectomy resulted in a significant increase in mean arterial pressure, left ventricular (LV)/body weight ratio, LV hydroxyproline concentration, plasma creatinine, blood urea nitrogen (BUN), and noradrenaline (NA) levels as well as significant decrease in LV papillary muscle developed tension in group II compared with the sham-operated group I. Administration of renalase to group III resulted in significant amelioration of all studied parameters with the exception of plasma creatinine and BUN which were not significantly different from nontreated group II. The results of the current study identify renalase as a new therapeutic modality that might modulate cardiac function and systemic blood pressure in renalase-deficient states like chronic renal disease.

Back to basics: pitting edema and the optimization of hypertension treatment in incident peritoneal dialysis patients (BRAZPD)

Systemic arterial hypertension is an important risk factor for cardiovascular disease that is frequently observed in populations with declining renal function. Initiation of renal replacement therapy at least partially decreases signs of fluid overload; however, high blood pressure levels persist in the majority of patients after dialysis initiation. Hypervolemia due to water retention predisposes peritoneal dialysis (PD) patients to hypertension and can clinically manifest in several forms, including peripheral edema. The approaches to detect edema, which include methods such as bioimpedance, inferior vena cava diameter and biomarkers, are not always available to physicians worldwide. For clinical examinations, the presence of pitting located in the lower extremities and/or over the sacrum to diagnose the presence of peripheral edema in their patients are frequently utulized. We evaluated the impact of edema on the control of blood pressure of incident PD patients during the first year of dialysis treatment. Patients were recruited from 114 Brazilian dialysis centers that were participating in the BRAZPD study for a total of 1089 incident patients. Peripheral edema was diagnosed by the presence of pitting after finger pressure was applied to the edematous area. Patients were divided into 2 groups: those with and without edema according to the monthly medical evaluation. Blood arterial pressure, body mass index, the number of antihypertensive drugs and comorbidities were analyzed. We observed an initial BP reduction in the first five months and a stabilization of blood pressure levels from five to twelve months. The edematous group exhibited higher blood pressure levels than the group without edema during the follow-up. The results strongly indicate that the presence of a simple and easily detectable clinical sign of peripheral edema is a very relevant tool that could be used to re-evaluate not only the patient's clinical hypertensive status but also the PD prescription and patient compliance.

Association between routine and standardized blood pressure measurements and left ventricular hypertrophy among patients on hemodialysis

BACKGROUND

Left ventricular (LV) hypertrophy is common among patients on hemodialysis. While a relationship between blood pressure (BP) and LV hypertrophy has been established, it is unclear which BP measurement method is the strongest correlate of LV hypertrophy. We sought to determine agreement between various blood pressure measurement methods, as well as identify which method was the strongest correlate of LV hypertrophy among patients on hemodialysis.

METHODS

This was a post-hoc analysis of data from a randomized controlled trial. We evaluated the agreement between seven BP measurement methods: standardized measurement at baseline; single pre- and post-dialysis, as well as mean intra-dialytic measurement at baseline; and cumulative pre-, intra- and post-dialysis readings (an average of 12 monthly readings based on a single day per month). Agreement was assessed using Lin's concordance correlation coefficient (CCC) and the Bland Altman method. Association between BP measurement method and LV hypertrophy on baseline cardiac MRI was determined using receiver operating characteristic curves and area under the curve (AUC).

RESULTS

Agreement between BP measurement methods in the 39 patients on hemodialysis varied considerably, from a CCC of 0.35 to 0.94, with overlapping 95% confidence intervals. Pre-dialysis measurements were the weakest predictors of LV hypertrophy while standardized, post- and inter-dialytic measurements had similar and strong (AUC 0.79 to 0.80) predictive power for LV hypertrophy.

CONCLUSIONS

A single standardized BP has strong predictive power for LV hypertrophy and performs just as well as more resource intensive cumulative measurements, whereas pre-dialysis blood pressure measurements have the weakest predictive power for LV hypertrophy. Current guidelines, which recommend using pre-dialysis measurements, should be revisited to confirm these results.

Salt and Fluid Intake in the Development of Hypertension in Peritoneal Dialysis Patients

BACKGROUND

Although fluid overload contributes to hypertension in CAPD patients, less attention has been paid to the role of excess salt and fluid intake. Therefore, we investigated the role of salt and fluid intake in the development of hypertension in CAPD patients.

METHODS

A total of 165 stable CAPD patients were included into this study. Based on the blood pressure in three consecutive months, they were divided into three groups: persistent hypertensive (PH; n = 33), intercurrent hypertensive (IH; n = 58) and persistent normotensive (PN; n = 74). The IH group was further divided into two phases: normotensive and hypertensive. Fluid status was evaluated by clinical assessment and bioimpedance analysis (BIA).

RESULTS

There were no differences in age, gender, and duration of dialysis among groups. Patients were more fluid overloaded in the PH group. Extracellular water (ECW), total body water (TBW), and normalized extracellular water by height (NECW) were higher in the PH group than the PN group (16.77 +/- 3.62 L vs. 14.61 +/- 2.92 L for ECW, p < 0.01; 32.22 +/- 8.23 L vs. 28.98 +/- 6.00 L for TBW, p < 0.05; and 10.28 +/- 1.86 L/m vs. 9.08 +/- 1.63 L/m for NECW, p < 0.01). However, patients in the PH group also had more total fluid removal (TFR) and total sodium removal (TSR) compared with the PN group (1346.82 +/- 431.27 mL/d vs. 1139.28 +/- 412.65 mL/d for TFR, p < 0.05; and 141.52 +/- 61.57 mmol/d vs. 102.42 +/- 62.51 mmol/d for TSR, p < 0.01). The same trend was demonstrated when compared values of hypertensive and normotensive phase in IH group; patients had higher ECW, TBW, NECW, TSR, and PNa when they were in hypertensive phase than in the normotensive phase.

CONCLUSIONS

This study confirmed that fluid overload was closely associated with the development of hypertension in CAPD patients. It also showed that hypertensive patients were in general more fluid overloaded despite a higher fluid and sodium removal as compared with normotensive patients.

Blood volume monitoring to adjust dry weight in hypertensive pediatric hemodialysis patients

The aim of this study was to adjust dry weight by short-term blood volume monitoring (BVM)-guided ultrafiltration and evaluate the effects of optimizing dry weight on blood pressure (BP) control and intradialytic symptoms (IDS) in a group of hypertensive hemodialysis (HD) patients. The study was performed in four sequential phases, each of which lasted for 1 week, on nine hypertensive HD patients (six girls, age 16.9 +/- 3.1 years). In phase I, patients were observed by BVM. In phase II, BVM was used to guide ultrafiltration to adjust dry weight. Antihypertensive drugs were gradually tapered or withheld in phase III, when the patients were hypotensive and/or their IDS increased. In phase IV, this particular weight was maintained without any intervention. Pre- and post-HD body weight, pre-HD, post-HD, 30 min after HD casual BP values, and IDS in each HD session were recorded. The BP was also assessed by 44-h ambulatory BP monitoring (ABPM), which is an ideal method to determine BP changes throughout the interdialytic period at the beginning of phase I and at the end of phase IV. There was a decrease in mean dry weight, all casual systolic BPs, and systolic/diastolic ABPM at the end of the study (all p < or = 0.05). Antihypertensive drugs were stopped in five patients and reduced in two during phase III of the study. The IDS was more frequent (36%) in phase IV than in phase I (16%); however, this increase did not reach statistical significance. The results of this study suggest that short-term BVM guided-ultrafiltration may be a useful tool to diagnose volume overload and to adjust dry weight and, consequently, to achieve a better control of BP in pediatric HD patients.

Sympathetic activation in chronic renal failure

The potential involvement of sympathetic overactivity has been neglected in this population despite accumulating experimental and clinical evidence suggesting a crucial role of sympathetic activation for both progression of renal failure and the high rate of cardiovascular events in patients with chronic kidney disease. The contribution of sympathetic neural mechanisms to the occurrence of cardiac arrhythmias, the development of hypertension, and the progression of heart failure are well established; however, the exact mechanisms contributing to heightened sympathetic tone in patients with chronic kidney disease are unclear. This review analyses potential mechanisms underlying sympathetic activation in chronic kidney disease, the range of adverse consequences associated with this activation, and potential therapeutic implications resulting from this relationship.

Hypertension awareness, treatment, and control in chronic kidney disease

BACKGROUND

Hypertension prevalence, awareness, treatment, and blood pressure control rates in the population with chronic kidney disease are limited. The objective of this study was to determine the state of blood pressure control in patients with chronic kidney disease.

METHODS

This is a cross-sectional analysis of data of participants with chronic kidney disease from the Kidney Early Evaluation Program. The Kidney Early Evaluation Program is a national-based health screening program for individuals at high risk for kidney disease conducted in 49 states and the District of Columbia. Of 55,220 adults with kidney disease, 10,813 completed information for demographic and medical characteristics used in the analysis. Predictors of blood pressure control were assessed using multiple logistic regression analysis.

RESULTS

Hypertension prevalence, awareness, and treatment proportions in the screened cohort were high (86.2%, 80.2%, and 70.0%, respectively), but blood pressure control rates were low (13.2%). These proportions increased with advancing stage of kidney disease. Elevated systolic blood pressure accounted for the majority of inadequate control. Male gender (odds ratio [OR] 0.86; 95% confidence interval [CI], 0.75-0.99), non-Hispanic black race (OR 0.76; 95% CI, 0.65-0.89), and body mass index of 30 kg/m(2) or more (OR 0.83; 95% CI, 0.73-0.94) were inversely related with blood pressure control. Those with stage 3 kidney disease were more likely to have blood pressure at goal than those with stage 1 kidney disease (OR 2.08; 95% CI, 1.55-2.80).

CONCLUSION

We conclude that despite increased awareness and treatment of hypertension, control rates in these participants are poor. This poor control rate centers around elevated systolic pressure in people who are obese, non-Hispanic black, or male. These data suggest that those who are aware of their kidney disease are more likely to achieve blood pressure control.

Exercício físico em pacientes dialisados

Pacientes portadores de doença renal crônica (DRC) submetidos a tratamento dialítico apresentam alterações físicas e psicológicas que predispõem ao sedentarismo. Nesta população, a prescrição rotineira de exercícios físicos não é uma prática freqüente, especialmente no nosso país. No entanto, alguns autores têm demonstrado que um programa de exercícios para estes pacientes contribui para o melhor controle da hipertensão arterial, da capacidade funcional, da função cardíaca, da força muscular e, conseqüentemente, da qualidade de vida. Além dos benefícios relacionados ao sistema cardiovascular, a realização do exercício traz benefícios secundários, pois quebra a monotonia do procedimento, melhora aderência e pode aumentar a eficácia da diálise. Na presente revisão, os autores discutem aspectos da realização de exercícios físicos em pacientes portadores de DRC em diálise e apresentam dados iniciais de sua experiência com a aplicação de exercícios supervisionados durante as sessões de hemodiálise.

ACE inhibitor-based, directly observed therapy for hypertension in hemodialysis patients

BACKGROUND

Hypertension is present in nearly 80% of dialysis patients yet adequately controlled in less than half. We designed a stepped antihypertensive regimen using long-acting antihypertensives (trandolapril, atenolol and amlodipine) administered thrice a week (TIW) after each hemodialysis, and compared blood pressure (BP) control, medication cost and pill burden to each patient's prior daily antihypertensive prescriptions.

METHODS

Patients were continued on their daily medications, pre-dialysis sitting BP was measured and a 44-hour interdialytic ambulatory BP monitoring (ABPM) was obtained. Then, their medications were stopped and replaced with trandolapril (2 mg TIW). Atenolol and/or amlodipine were also given TIW if the patients had any member of these classes of drugs as part of their daily regimen. Medications were titrated every 2 weeks to achieve a pre-dialysis mean arterial pressure (MAP) of <107 mm Hg. After 2 consecutive weeks with a pre-dialysis MAP of <107 mm Hg, a second 44-hour ABPM was obtained.

RESULTS

Ten patients completed the study. A persistent MAP of <107 was maintained in all 10 patients after conversion to TIW dosing. The systolic BP decreased from 122.2 +/- 7.1 to 116.4 +/- 11.6, and the diastolic BP decreased from 75.3 +/- 10.4 to 70.4 +/- 11.4 mm Hg. Pill burden and cost of medications were also significantly less.

CONCLUSIONS

This pilot study found that ACE inhibitor-based, directly observed TIW therapy to be effective in hemodialysis patients with mild to moderate hypertension. Larger trials of directly observed therapy for hypertension in dialysis patients are warranted.

Sympathetic hyperactivity in haemodialysis patients is reduced by short daily haemodialysis

OBJECTIVE

Haemodialysis patients often have sympathetic hyperactivity. The hypothesis of this study was that a switch from three times weekly to short daily dialysis could affect sympathetic hyperactivity.

METHODS

We studied 11 patients (eight men; aged 46 +/- 8 years) stable on haemodialysis for at least 1 year before and 6 months after conversion from three times to six times weekly dialysis without increasing total dialysis time (short daily dialysis). Seven patients were restudied 2 months after switching back to three times weekly haemodialysis.

RESULTS

Ultrafiltration volume per session decreased from 2.4 +/- 1.0 to 1.5 +/- 0.6 l (P < 0.05). The extracellular fluid volume (bromide distribution space) did not change. Mean arterial pressure (without medication) decreased from 113 +/- 11 to 98 +/- 9 mmHg (P < 0.05). Cardiac output (Doppler echocardiography) did not change, but peripheral vascular resistance decreased from 25.4 +/- 6.4 to 21.2 +/- 3.2 mmHg per min/l (P < 0.05), in conjunction with a decrease in muscle sympathetic nerve activity (MSNA) from 39 +/- 19 to 28 +/- 15 bursts/min (P < 0.05). Ambulant 24 h blood pressure decreased and the nocturnal blood pressure dip increased during short daily dialysis. The seven patients who were switched back to alternate day haemodialysis showed a return of the high MSNA and peripheral vascular resistance.

CONCLUSION

The study shows that sympathetic hyperactivity in haemodialysis patients is reduced by increasing the frequency of treatment sessions. This is probably because of the decrease in number or magnitude of the fluid fluctuations.

[Coronary artery disease and coronary angioplasty in chronic hemodialysis patients]

Chronic renal insufficiency leads to many cardiovascular complications and provide worst prognosis, especially when patients need hemodialysis. The atherosclerosis of chronic hemodialysis patients is qualified as "accelerated" by some authors, because of a very fast and large progression. To improve prognosis, it seems to be very important to detect and treat the frequent and serious underlying cardiovascular disease. Because of the high rate of diabetes mellitus, silent ischemia is a very frequent clinical situation. In the other hand, coronary artery disease in chronic hemodialysis patients is frequently complex, with a large coronary extension and high rate of coronary calcifications. Consequently, this disease needs a specific therapeutic approach. Even though, percutaneous coronary interventions (PCI) are more complex in this population, it provides good results, and improves patient's prognosis. However, the rate of complications of the vascular approach and the rate of restenosis is high. New devices, such as Drug Eluting Stents (DES) can critically decrease restenosis rate, and closure devices for trans-femoral approach, provides very encouraging results in this high risk population. Despite, good results of PCI with DES use, the mortality is still high in this population. To improve our efficiency, we have to progress in our therapeutic strategies and optimize medical approach to treat the important biological perturbations.

Fluid balance, dry weight, and blood pressure in dialysis

The total amount of sodium present in the body controls the extracellular volume. In advanced renal failure, sodium balance becomes positive and the extracellular volume expands. This leads to hypertension, and vascular changes that lead to adverse cardiovascular consequences in dialysis patients. Controlling the body sodium content and the extracellular volume allows one to better control hypertension and its consequences. This can be achieved by reducing the sodium input (sodium dietary restriction and reasonably low sodium dialysate) and/or by increasing the sodium output (ultrafiltration by convection). The discontinuous nature of hemodialysis causes saw-tooth volume fluctuations. This has led to the concept of dry weight (DW), a crucial component of dialysis adequacy. Assessment and achievement of DW is feasible on pure clinical grounds. But its relative lack of accuracy (and the physicians' progressive lack of interest in bedside examination) has led to several nonclinical methods of assessing DW in an effort to improve the assessment of fluid status in dialysis patients.

Antihypertensive Therapy in the Presence of Proteinuria

The presence of proteinuria is a well-known risk factor for both the progression of renal disease and cardiovascular morbidity and mortality, and decreases in urine protein excretion level were associated with a slower decrease in renal function and decrease in risk of cardiovascular events. Increased blood pressure has a major role in the development of proteinuria in patients with either diabetic or nondiabetic kidney disease, and all recent guidelines recommend a blood pressure goal less than 130/80 mm Hg in patients with proteinuria to achieve maximal renal and cardiovascular protection. Drugs interfering with the renin-angiotensin system, ie, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, should be used as first-line antihypertensive therapy in patients with proteinuria because they seem to have a blood pressure-independent antiproteinuric effect, and if blood pressure levels are still out of goal, a diuretic should be added to this regimen. A combination of an angiotensin-converting enzyme inhibitor with an angiotensin receptor blocker or other classes of medications shown to decrease protein excretion, such as nondihydropyridine calcium antagonists or aldosterone receptor blockers, should be considered to decrease proteinuria further. This review provides an extended summary of current evidence regarding the associations of blood pressure with proteinuria, the rationale for currently recommended blood pressure goals, and the use of various classes of antihypertensive agents in proteinuric patients.

Management of hypertension in hemodialysis patients

The relationship of hypertension with adverse outcomes is uncertain in the hemodialysis population. If hypertension is an etiologically significant cardiovascular risk factor in hemodialysis patients, the first step would be to assess the level of BP accurately. BP obtained at home over a week and averaged using a validated oscillometric automatic device can prove valuable. To the extent BP lowering influences cardiovascular outcomes, home BP of 150/90 mm Hg would warrant therapy, since it correlates with target organ damage and hypertension diagnosed by ambulatory BP monitoring. To manage hypertension, limiting dietary sodium intake and individualizing dialysate sodium delivery would be first steps. The magnitude of reduction in BP with dietary sodium restriction and the whether dialysate sodium can be safely limited in those who are hypotension-prone is unclear. Antihypertensive drug therapies can effectively reduce BP and are needed by the vast majority of hemodialysis patients. Whether control of hypertension translates into better outcomes is not known, but collective evidence suggests that hypertension should be controlled in hemodialysis patients.

Residual Renal Function and Volume Control in Peritoneal Dialysis Patients

BACKGROUND

Fluid overload is not uncommon in patients on continuous ambulatory peritoneal dialysis (CAPD). Previous studies suggested that residual renal function (RRF) played an important role in maintaining fluid balance. However, good fluid status should be a balance between fluid intake and removal. Therefore, in the present study, we investigated the effect of RRF on patients' fluid status after focusing on the balance between fluid intake and removal in CAPD patients.

METHODS

In this cross-sectional study, 195 stable CAPD patients in a single center were included. Patients were divided into three groups according to their urine output: anuric group with urine < or =100 ml/day, oliguric group with urine < or =400 ml/day and UO >400 ml group with urine >400 ml/day. Fluid status was evaluated by bioimpedance analysis and mean arterial pressure (MAP). The sodium removal and plasma sodium concentration were also measured. All the patients were educated to try to achieve good volume control by focusing on salt and fluid intake and their removals.

RESULTS

There were 51, 31 and 113 patients in anuric, oliguric and UO >400 ml group, respectively. Anuric patients were older and had been on CAPD longer than that of the oliguric and UO >400 ml patients (p < 0.05). The urine output in the three groups were 9.28 +/- 22.68, 236.13 +/- 75.43 and 1,013.34 +/- 541.54 ml/day, respectively (p < 0.001). Bioimpedance analysis showed that the differences of extracellular water, intracellular water and total body water were not statistically significant among the three groups. However, there was significant difference in MAP among the three groups (MAP in anuric, oliguric and UO >400 ml groups were 93.27 +/- 13.35, 96.63 +/- 9.94 and 102.36 +/- 13.70 mm Hg, p < 0.01), and UO >400 ml group had higher MAP than anuric and oliguric groups (p < 0.05). The total sodium removal (renal + peritoneal) in anuric, oliguric and UO >400 ml groups were 96.44 +/- 60.18, 98.95 +/- 73.82 and 134.64 +/- 72.44 mmol/day, respectively (p < 0.01). The UO >400 ml group also had higher plasma sodium concentration than anuric and oliguric groups (plasma sodium in the three groups were 137.49 +/- 3.43, 137.82 +/- 2.63 and 139.15 +/- 3.30 mmol/l, respectively; p < 0.01).

CONCLUSIONS

This study showed that extracellular water among anuric, oliguric and UO >400 ml groups was not significantly different, which suggested that RRF may be not so important as expected in maintaining good volume status. The higher blood pressure in patients with higher RRF and higher sodium and fluid removal in the present study suggested restricting salt and fluid intake might be more important for better blood pressure control in CAPD patients.

Blood pressure instability during hemodialysis

Most patients with end-stage renal disease (ESRD) maintained on hemodialysis have chronic hypertension. However, hypotension is a frequent complication of hemodialysis, probably because of impaired baroreflex function. Less frequently, increases in pressure can be a complication of hemodialysis. Detailed studies of patients with these abnormalities in arterial pressure during hemodialysis may yield insights into the regulation of arterial pressure during ESRD.

Potential cardiovascular risk factors in paediatric renal transplant recipients

Cyclosporin (CsA) therapy is associated with side effects such as hypertension, hyperlipidemia and nephrotoxicity. Tacrolimus (Tac) has been shown to be more favourable in this respect. We retrospectively analysed office blood pressure (BP), serum total cholesterol (TC) and fasting glucose levels, and estimated graft function profiles in paediatric (n =56) and young adult (n =14) renal transplant recipients whose maintenance immunosuppressive regimen was based upon CsA (n =38) or Tac (n =32) given with mycophenolate mofetil and corticosteroids. The analysis was performed at four different time-points: at 1, 6, 12, and 24 months post-transplant, respectively. Baseline characteristics were comparable between treatment groups. Differences for both systolic and diastolic BP, and graft function between treatment groups became significant from month 1 and throughout the 2-year period. Values (mean +/- SD) for CsA-treated and Tac-treated recipients at 2 years were 118.8+/-11.1 / 74.6+/-7.4 mmHg vs 109.3+/-11.2 / 67.2+/-7.8 mmHg for systolic and diastolic BP, respectively, p <0.005/0.005; and 72.0+/-18.5 ml/min vs 84.0+/-22.4 ml/min per 1.73 m(2) for graft function, respectively, p <0.01. Office hypertension, defined as the use of antihypertensive medication at month 24, was significantly associated with CsA-therapy (chi(2), p <0.01). TC levels became significantly lower at months 6, 12, and 24 in the Tac group compared with the CsA group. Hypercholesterolemia, defined as TC>or=200 mg/dl, was significantly associated with CsA-based immunosuppressive regimen at months 6, 12, and 24 post-transplant (chi(2), p <0.05, p <0.001, and p <0.01, respectively). Although Tac therapy was associated with higher glucose levels, no recipient developed post-transplant diabetes mellitus. The number of recipients who experienced acute rejections was comparable in both groups. In conclusion, Tac-based immunosuppressive therapy was found to be associated with more favourable potential risk-factor profiles for cardiovascular disease and better graft function at 2 years post-transplant compared with CsA-therapy.

Coronary-artery calcium scores using electron beam CT in patients with chronic renal failure

We evaluated the risk of coronary-artery disease in patients with chronic renal failure (CRF) by measuring the coronary-artery calcium scores with electron beam CT (EBCT). A total of 81 CRF patients were divided into three groups; pre-dialysis (group I, n = 35), hemodialysis (group II, n = 31) and peritoneal dialysis (group III, n = 15). The several serum biochemical markers and calcium score levels by EBCT were determined. The Ca x P products were significantly higher in groups II (p < 0.05) and III (p < 0.01) than in group I. The serum calcium levels were significantly higher in group III than in both group I (p < 0.01) and II (p < 0.05). The serum calcium level in 15 patients with a calcium score > 400 was significantly higher than the 66 patients with a score < or =400 (p < 0.01). The calcium score was significantly higher in the 15 patients with cardiovascular complications than in the 66 patients without cardiovascular complications (628.9+/-904.8 vs. 150.4+/-350.9, p < 0.01). EBCT seemed to be a good diagnostic tool for evaluating the risk of coronary-artery disease ''noninvasively'' in CRF patients who are at increased risk of cardiovascular morbidity and mortality.

Hypertension in pediatric patients on long-term dialysis: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

BACKGROUND

Elevated blood pressure (BP) is frequent in children on long-term dialysis therapy. However, the prevalence of hypertension and status of BP control in these patients are lacking. Using the North American Pediatric Renal Transplantation Cooperative Study database, we determined the prevalence of hypertension and assessed risk factors for elevated BP during long-term dialysis therapy in children.

METHODS

The study cohort included 3,743 patients (age, 0 to 21 years). Uncontrolled hypertension is defined as BP equal to or greater than age-, sex-, and height-specific 95th percentiles; controlled hypertension was considered in children who were administered antihypertensive medications, but had BP less than the 95th percentile.

RESULTS

A total of 76.6% of patients had either uncontrolled (56.9%) or controlled (19.7%) hypertension at baseline. Normotensive children at baseline had significant BP increases, whereas hypertensive children at baseline had significant BP decreases during the first year of dialysis therapy. BP did not change significantly after 1 year of dialysis therapy; 51% of patients had uncontrolled hypertension after 1 year of maintenance dialysis therapy. Logistic regression analysis shows that baseline hypertensive status and use of BP medications are both large significant risk factors for subsequent hypertension. Other risk factors include young age, acquired cause of renal failure, black race, initiation of dialysis therapy in 1992 to 1997, and hemodialysis as a mode of renal replacement therapy.

CONCLUSION

Hypertension is very prevalent and difficult to control in children on dialysis therapy. Results also suggest that the initial months on maintenance dialysis therapy might be the window of opportunity when careful monitoring and aggressive management of hypertension would allow achieving BP control in these patients.

Volume Status and Blood Pressure in Continuous Ambulatory Peritoneal Dialysis Patients

The pathophysiology of hypertension in dialysis patients is largely attributed to positive sodium balance and volume expansion. Whereas the relationship between fluid status and blood pressure control in hemodialysis patients is well established, this relationship is not well studied in peritoneal dialysis patients.

METHODS

100 stable CAPD patients who had been dialyzed for more than 3 months, as well as 60 healthy controls, were studied cross-sectionally. CAPD patients were divided into three groups according to their blood pressure level: group 1 (normotension), group 2 (controlled hypertension with antihypertensive medication (AHM)) and group 3 (uncontrolled hypertension with AHM). Extracellular water (ECW) and intracellular water (ICW) were measured using bioimpedance spectroscopy in all subjects. Dialysis adequacy and transport test was conducted in each patient.

RESULTS

Height normalized ICW (nICW) was much lower, and ECW/ICW was higher in both male and female dialysis patients as compared to healthy controls. nECW was also significantly higher in group 3 when compared to group 1. The dose of AHM was similar in group 2 and group 3. In female CAPD patients, there were no differences in urinary volume (UV) and the total fluid removal among the three patient groups. However, in male CAPD patients, UV and total fluid removal were significantly higher in group 3 than in group 1. Renal and total removal of sodium was also significantly higher in group 3 male patients than group 1.

CONCLUSIONS

Peritoneal dialysis patients with uncontrolled hypertension are more volume overloaded and their blood pressure may be difficult to control by AHM alone. These findings indicate that volume control preferably by dietary salt and fluid restriction should be intensified in hypertensive CAPD patients.

Is Hypertension a Disorder of Volume Control? What Is the Evidence?

The etiological factors responsible for the hypertensive phenotype are complex and several experimental and clinical observations point to a major role of the kidney as being responsible. Genetic studies of uncommon diseases which express monogenetic inheritance all have in common a dysregulation of Na+ balance and volume expansion. Furthermore, epidemiological data suggest an increased incidence of hypertension in communities with high excretory rates of Na+. Experimental data also suggest that low birth weight is associated with an increase in the frequency of hypertension later in life and raises the possibility that intrauterine imprinting may contribute to the expression of the phenotype. Upregulation of the Na+/K+/2Cl- and thiazide-sensitive transporters in low birth weight animals may provide the physiological basis for these observations. In addition, low birth weight is associated with a decrease in nephron number. Therefore, low nephron number may induce adaptive changes in utero which influence volume homeostasis later in life and subtle gain of function mutations in one or more of these transporters may unmask defects in volume homeostasis with increasing salt intake. Finally, the high prevalence of hypertension in functionally anephric patience seems to respond to sustained maintenance of 'dry weight' through ultrafiltration.