The Effects of Phosphate on Microvascular Function
试验速览
- 阶段
- 不适用
- 发起方
- 入组人数
- 20
- 主要终点
- % Change in flux of blood after skin heating to 44 C as measured using laser-Doppler flowmtery.
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Diagnostic
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
盲法说明
The pharmacy dispensing the drug will be responsible for generating placebo and distributing drug. The investigators, care providers and patient will not have access to this data. Study outcomes will be comparing arms but not with knowledge of which arm occurred when.
入排标准
- 年龄范围
- 21 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Diagnosis of ESRD on hemodialysis (HD) for >90 days.
- •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.
排除标准
- •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).
研究组 & 干预措施
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.
Intervention
Participants will take a placebo instead of standard care with a phosphate binder, for 2 weeks.
干预措施: Withholding standard phosphate binder (Other)
结局指标
主要结局
% Change in flux of blood after skin heating to 44 C as measured using laser-Doppler flowmtery.
时间窗: 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.
次要结局
- Change in capillary count seen post occlusion from pre occlusion, as determined by nail-fold capillaroscopy.(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))