Dietary Salt in Postural Tachycardia Syndrome
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 38
- 试验地点
- 2
- 主要终点
- Plasma Volume
研究概览
简要总结
Patients with POTS may not adequately expand their plasma volume in response to a high-sodium (Na+) diet. Mechanisms involved in the regulation of plasma volume, such as the renin-angiotensin-aldosterone system and renal dopamine, may be impaired in POTS and may respond inappropriately to changes in dietary sodium.The purpose of this study is to determine (1) whether a high dietary sodium level appropriately expands plasma volume in POTS; (2) whether plasma renin activity and aldosterone are modified appropriately by changes in dietary sodium in POTS; and (3) whether patients with POTS have improvements in their orthostatic tachycardia and symptoms as a result of a high dietary sodium level.
详细描述
Study Day 1
- Start 150 milliequivalents (mEq) Na+/day diet (POTS patients as inpatients; healthy control subjects with clinical research center (CRC)- provided outpatient diet)
- Start a 24h urine collection (for Na+, K+, Cr, fractionated catecholamines)
- Blood work
- Blood volume - carbon monoxide rebreathing
Study Day 2
- Complete 24h urine
- Start STUDY DIET (10 mEq Na+/day or 300 mEq Na+/day in a random order) after 3 meals of 150 mEq Na+/day are complete; water ad lib
Study Day 3 - 5
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 50 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Diagnosed with postural tachycardia syndrome by the Vanderbilt Autonomic Dysfunction Center
- •Increase in heart rate ≥30 beats/min with position change from supine to standing (10 minutes)
- •Chronic symptoms consistent with POTS that are worse when upright and get better with recumbence
- •Age between 18-50 years old
- •Non-smokers
- •Premenopausal patients with POTS and healthy volunteers
- •Only female participants are eligible.
- •Since 80-90% of POTS patients are female, and there can be differences in measures with the menstrual cycle, including a small number of males might introduce a significant amount of noise.
- •Able and willing to provide informed consent
排除标准
- •Overt cause for postural tachycardia, i.e., acute dehydration
- •Significant cardiovascular, pulmonary, hepatic, or hematological disease by history or screening results
- •Pregnant (positive pregnancy test) or breastfeeding
- •Hypertension defined as supine resting BP>145/95 mmHg off medications or needing antihypertensive medication
- •Other factors which in the investigator's opinion would prevent the participant from completing the protocol, including poor compliance during previous studies or an unpredictable schedule
- •Unable to give informed consent
结局指标
主要结局
Plasma Volume
时间窗: after 7 days of each dietary sodium level
Plasma volume (PV) was determined by the indicator tracer-dilution technique, using the DAXOR Blood Volume Analyzer (BVA)-100 system (DAXOR Corporation), on Day 7 of the low sodium and high sodium dietary interventions. Outcome data are the absolute values for PV on Day 7 for each diet.
次要结局
- Magnitude of Suppression of Plasma Renin Activity (From Low Sodium to High Sodium Diets)(Upright blood samples were collected after up to 30 minutes of standing on the 7th day of each dietary sodium intervention)
研究者
Alfredo Gamboa
Research Associate Professor of Medicine
Vanderbilt University