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NCT Number: NCT00759967

Conventional Hemodialysis vs. Short Daily Hemodialysis (6 Days / Week) and Mechanisms of Blood Pressure Control

More than 80% of patients with end stage renal disease have hypertension; 70% of whom are poorly controlled using conventional Hemodialysis therapy. An expanded extracellular fluid volume and an increase in peripheral vascular resistance as a result of hemodynamic/trophic effects of an increased sympathetic nerve activity, angiotensin II, asymmetrical dimethyl arginine, and decreased nitric oxide are the most frequently quoted mechanisms contributing to hypertension in this population. The intermittent nature of conventional hemodialysis treatments (4 hours, 3 days/week) results in the majority of patients having a sustained expansion of the extracellular fluid volume that likely contributes to the activation of neurohormonal pathways. However, daily therapy including short daily hemodialysis (2 hours, 6 days/week) and nocturnal hemodialysis (6-8 hours, 5-6 days/week) improve or even normalize blood pressure. Short daily hemodialysis appears to improve blood pressure secondary to a reduction in extracellular fluid volume (7,8) whereas the improvement in blood pressure with nocturnal hemodialysis occurs by a reduction in peripheral vascular resistance (8,9,10). This is consistent with the Katzarski et al experience (7-8 hours, 3 days/week) and one randomized controlled trial in which blood pressure control was due to normalization of extracellular fluid volume in some patients and a reduction in peripheral vascular resistance in others. The majority of the studies in daily dialysis are observational, do not include a run-in period to optimize blood pressure management and have not explored the mechanisms of improvement in blood pressure in detail. We have designed a 9 month study to determine if the mechanism by which short daily hemodialysis is associated with an improvement in blood pressure control is secondary to changes in sympathetic nervous system activity and/ or extracellular fluid volume. Additionally we would like to explore the potential impact of short daily dialysis, compared to conventional dialysis, on markers of inflammation and oxidative stress in detail.

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Key information

Conditions

End Stage Renal Disease Chronic Disease Disease Attributes Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Kidney Diseases Kidney Failure, Chronic Male Urogenital Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Renal Insufficiency Renal Insufficiency, Chronic Urogenital Diseases Urologic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The Ottawa Hospital

Ottawa, Ontario, K1H 7W9, Canada

About this study

Patients with end stage renal disease have an adjusted risk of cardiovascular mortality that is 10-20 times greater than the general population. Of the modifiable risk factors, hypertension occurs in 80% of patients with end stage renal disease and is poorly controlled in 70% of patients. In several observational studies of daily hemodialysis, blood pressure has improved despite a reduction in the number of antihypertensive medications. A randomized crossover study in short daily hemodialysis also showed an improvement in systolic blood pressure and a reduction in left ventricular mass index. In limited investigation, the mechanism(s) responsible for the improvement in blood pressure have been attributed to a reduction in extracellular fluid volume (short daily) and a reduction in peripheral vascular resistance (nocturnal hemodialysis). The studies to date have been limited by failing to include a run in phase to optimize extracellular fluid volume prior to the initiation of daily dialysis. Additionally, only one study used a standardized algorithm for the management of blood pressure which is vital as the treatments are not blinded. We have designed a randomized, unblinded, 9 month cross-over study to determine the mechanism of blood pressure control on patients receiving conventional (3 times /week) HD to short daily HD (6 times /week 2 hrs/tx). After completing a 3 month run-in phase on conventional HD in which patient's dry weight and antihypertensive medications will be adjusted using a standardized algorithm, patients are to be randomized to a 3 month cross-over of daily HD versus conventional HD. The mechanism of improved blood pressure control will be explored using bioelectrical impedance to measure extracellular fluid volume (ECFV) and muscle sympathetic nerve activity (MSNA) as well as plasma catecholamines to measure the activity of the sympathetic nervous system. Additionally the effect of short daily HD, compared to conventional HD, on reactive oxygen species and markers of inflammation will be examined in Dr. Rhian Touyz lab. Lastly we will determine the patient's treatment preference.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Systolic Hypertension
  • They are able to make the time commitment for daily therapy
  • They are capable of giving informed consent.

Exclusion criteria

  • They are expected to receive a transplant within the next 12 months
  • If they are considering a switch to peritoneal dialysis
  • They are not expected to survive 12 months
  • They have infections that require isolation (Vancomycin Resistant Enterococcus, Methicillin Resistant Staphylococcus Aureus, Hepatitis B)
  • They have known symptomatic dilated cardiomyopathy (New York Association Class II or III with left ventricle ejection fraction of <0.35

Treatment and study plan

Microneurography

Procedure

Muscle sympathetic nerve activity measurement will be obtained using microneurography. Approximately 10-20% of microneurography recordings are not interpretable due to technical problems. For this reason, blood samples will be collected at the same time that the microneurography is to be done. These test will be done at 3 time points throughout the study.

Other names: Catecholamines

Bioimpedance testing

Procedure

bioimpedance measurement of extracellular fluid volume will be measured at the end of each 3 month period. This test will be done at 3 time points throughout the study.

Other names: Bioimpedance, extracellular fluid volume measurement

Primary outcomes

  1. Mean Systolic Blood Pressure Over the Third Month of Each Treatment Arm

    Time frame: Average of the last month of the 3 month intervention

    The average of 2 measurements taken pre each dialysis session in the third month of treatment were compared when the patients were on conventional hemodialysis compared to short daily hemodialysis. SBP was taken in accordance with guidelines from the Canadian Hypertension Society

Secondary outcomes

  1. To Determine if the Mechanism by Which Short Daily Hemodialysis is Associated With Changes in Extracellular Fluid Volume

    Time frame: once the final participant has completed all intervention procedures, approx. 3 months

    The extracellular fluid volume will be measured using bioelectrical impedance to determine if the mechanism by which short daily hemodialysis is associated with an improvement in blood pressure control is secondary to changes in extracellular fluid volume.

  2. To Determine if Short Daily Hemodialysis, Compared to Conventional Hemodialysis Maintains Metabolic Homeostasis

    Time frame: once the last participant has completed run in phase and after randomization, approx. 3 months

    Serum phosphate values from the end of the three month run in phase and after randomization used to measure metabolic homeostasis

  3. To Determine if the Enhance Control of Blood Pressure With Daily Hemodialysis Compare to Conventional Hemodialysis is Associated With a Reduction in Oxidative Stress.

    Time frame: once the final participant has completed all intervention procedures, approx. 3 months

  4. To Determine Patient Modality Preference.

    Time frame: at study completion

    each participant will complete a questionaire regarding modality preference

  5. To Determine if the Enhance Control of Blood Pressure With Daily Hemodialysis Compare to Conventional Hemodialysis is Associated With a Reduction in Markers of Inflammation

    Time frame: once the final participant has completed all intervention procedures, approx. 3 months

Sponsors and collaborators

Lead sponsor

Ottawa Hospital Research Institute

Other

Collaborators

  • Heart and Stroke Foundation of Ontario
  • University of Ottawa

Registry information

Official study title

Randomized Cross-over Study of Short Daily Hemodialysis Compared to Conventional Hemodialysis to Determine the Mechanisms of Hypertension Control

Important dates

Study start
2007
Primary completion
2011
Study completion
2012
First posted
Sep 25, 2008
Registry last updated
Aug 4, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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