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Phosphate Microvascular Study

23 augusti 2018 uppdaterad av: Veterans Medical Research Foundation

The Effects of Phosphate on Microvascular Function

Elevated phosphate concentrations in the blood have been associated with multiple negative health outcomes in patients with chronic kidney disease as well as in the general population. These negative outcomes include an increased risk of vascular complications like heart attack and stroke. While complications like heart attack and stroke reflect obstructive disease in large blood vessels, recent evidence suggests that elevated phosphate concentrations may first lead to disease in small blood vessels.

This single site clinical trial will randomize 20 veterans with end stage renal disease on hemodialysis to either a phosphate binder or placebo and evaluated for changes in their microvascular function using laser-Doppler flowmtery and nail-fold capillaroscopy.

Studieöversikt

Status

Okänd

Betingelser

Intervention / Behandling

Detaljerad beskrivning

Project Background: Recent studies have suggested that increased serum phosphate and phosphate intake may acute impair microvascular blood flow. However, this has never been directly tested using imaging techniques that directly measure microvascular flow. The end-stage renal disease population on hemodialysis at the VA San Diego is an ideal population to evaluate this effect.

Project Question: Does reduction of serum phosphate through the use of a phosphate binder (lanthanum carbonate) increase microvascular blood flow in persons with ESRD? Project Methods: The investigators propose a 4 week, randomized, double-blinded, placebo controlled, single-center, crossover trial. Participants will have their microvascular function assessed at the baseline of the study using laser-Doppler flowmetry and nail-fold capillaroscopy. They will then be randomized to either lanthanum carbonate or placebo for 2 weeks. Microvascular measurements will be repeated at the end of the 2 week period. Participants will then cross-over to the other study arm. After 2 weeks in the other study arm, they will have microvascular measurements repeated and the trial will then be complete. The primary outcome of the study will be the % change in skin blood flow after heating from 31 degrees Celsius to 44 degrees Celsius. This will be compared within each individual after they complete each arm of the study. Changes seen on nail-fold capillaroscopy, acceptability, safety, and adherence will be key secondary outcomes.

Studietyp

Interventionell

Inskrivning (Förväntat)

20

Fas

  • Inte tillämpbar

Kontakter och platser

Det här avsnittet innehåller kontaktuppgifter för dem som genomför studien och information om var denna studie genomförs.

Deltagandekriterier

Forskare letar efter personer som passar en viss beskrivning, så kallade behörighetskriterier. Några exempel på dessa kriterier är en persons allmänna hälsotillstånd eller tidigare behandlingar.

Urvalskriterier

Åldrar som är berättigade till studier

21 år och äldre (Vuxen, Äldre vuxen)

Tar emot friska volontärer

Nej

Kön som är behöriga för studier

Allt

Beskrivning

Inclusion Criteria:

  • Diagnosis of ESRD on hemodialysis (HD) for >90 days.
  • Age >21.
  • Capacity to understand and sign informed consent as assess by principal investigator.
  • On a phosphate binder with stable dose for >2 weeks.
  • Serum phosphate at screening visit of <7.0.

Exclusion Criteria:

  • Pregnancy.
  • Actively breastfeeding.
  • Use of oral contraceptives.
  • Inability to take oral medications.
  • History of medication non-compliance as assessed by the treating physician.
  • Patients currently enrolled in another trial.
  • Planned or expected surgical procedure during study period.
  • Planned or expected hospitalization during study period.
  • Corrected serum calcium greater than 10.2 mg/dl.
  • Serum intact PTH >1000 pg/ml
  • Albumin < 3 g/dl.
  • Allergy or intolerance to lanthanum carbonate.
  • Principal investigator deems patient to be unsuitable.
  • Non-English speaking persons. (Study performed at VA, therefore do not anticipate this represents a significant portion of the population).

Studieplan

Det här avsnittet ger detaljer om studieplanen, inklusive hur studien är utformad och vad studien mäter.

Hur är studien utformad?

Designdetaljer

  • Primärt syfte: Diagnostisk
  • Tilldelning: Randomiserad
  • Interventionsmodell: Crossover tilldelning
  • Maskning: Fyrdubbla

Vapen och interventioner

Deltagargrupp / Arm
Intervention / Behandling
Inget ingripande: Standard
Participants will have their hyperphosphatemia managed with lanthanum carbonate 1 g with meals and 500 mg with snacks as per typical care, for 2 weeks.
Placebo-jämförare: Intervention
Participants will take a placebo instead of standard care with a phosphate binder, for 2 weeks.
Övrig: Withholding standard phosphate binder
In this trial, placebo represents the intervention and not the control. Standard therapy for hyperphosphatemia in end-stage renal disease includes treatment with a phosphate binder. In this trial the intervention will be to withhold the phosphate binder and use placebo instead. In this way the effect of a higher serum phosphate can be evaluated.

Vad mäter studien?

Primära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
% Change in flux of blood after skin heating to 44 C as measured using laser-Doppler flowmtery.
Tidsram: Performed at initial study visit, at the end of the first arm of the study (Day 14) and again at the end of the second arm of the study (Day 28)
Flux of blood through skin will be measured using a Perimed PF5000. This will be performed at baseline in a temperature controlled room. Baseline skin measurements will be made at 31C. Skin will then be heated to 44 C. The percent change will be the outcome. This outcome will be compared within each person at the conclusion of each arm. Measurements will all be made on the Monday or Tuesday, the day of the participant's first dialysis treatment of the week. Measurements will be made prior to dialysis.
Performed at initial study visit, at the end of the first arm of the study (Day 14) and again at the end of the second arm of the study (Day 28)

Sekundära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
Change in capillary count seen post occlusion from pre occlusion, as determined by nail-fold capillaroscopy.
Tidsram: Performed at initial study visit, at the end of the first arm of the study (Day 14) and again at the end of the second arm of the study (Day 28)
Participants will undergo nail fold capillaroscopy using a CapiScope (KK Technology, Honiton United Kingdom) at baseline and then at the end of each treatment arm. Using a capillarascope a capillary count will be made. After measurement a BP cuff will be inflated to 200 mm Hg occlude flow to a single digit for 1 minute. 30 sec after release the count will be made again. This change will be compared within individuals between measurements made at the completion of each arm in the study. Measurements will all be made on the Monday or Tuesday, the day of the participant's first dialysis treatment of the week. Measurements will be made prior to dialysis. Values at the end of each treatment arm will be compared.
Performed at initial study visit, at the end of the first arm of the study (Day 14) and again at the end of the second arm of the study (Day 28)

Samarbetspartners och utredare

Det är här du hittar personer och organisationer som är involverade i denna studie.

Sponsor

Veterans Medical Research Foundation

Samarbetspartners

San Diego Veterans Healthcare System

Publikationer och användbara länkar

Den som ansvarar för att lägga in information om studien tillhandahåller frivilligt dessa publikationer. Dessa kan handla om allt som har med studien att göra.

Allmänna publikationer

Studieavstämningsdatum

Dessa datum spårar framstegen för inlämningar av studieposter och sammanfattande resultat till ClinicalTrials.gov. Studieposter och rapporterade resultat granskas av National Library of Medicine (NLM) för att säkerställa att de uppfyller specifika kvalitetskontrollstandarder innan de publiceras på den offentliga webbplatsen.

Studera stora datum

Studiestart (Förväntat)

1 januari 2019

Primärt slutförande (Förväntat)

1 januari 2021

Avslutad studie (Förväntat)

17 juli 2021

Studieregistreringsdatum

Först inskickad

9 juli 2018

Först inskickad som uppfyllde QC-kriterierna

18 juli 2018

Första postat (Faktisk)

20 juli 2018

Uppdateringar av studier

Senaste uppdatering publicerad (Faktisk)

24 augusti 2018

Senaste inskickade uppdateringen som uppfyllde QC-kriterierna

23 augusti 2018

Senast verifierad

1 augusti 2018

Mer information

Termer relaterade till denna studie

Nyckelord

Ytterligare relevanta MeSH-villkor

Andra studie-ID-nummer

  • VAH170095

Plan för individuella deltagardata (IPD)

Planerar du att dela individuella deltagardata (IPD)?

Ja

IPD-planbeskrivning

de-identified data may be shared at end of study

IPD-delning som stöder informationstyp

  • Studieprotokoll
  • Statistisk analysplan (SAP)
  • Informerat samtycke (ICF)

Läkemedels- och apparatinformation, studiedokument

Studerar en amerikansk FDA-reglerad läkemedelsprodukt

Nej

Studerar en amerikansk FDA-reglerad produktprodukt

Nej

produkt tillverkad i och exporterad från U.S.A.

Ja

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