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Completed

NCT Number: NCT01983826

Dietary Nitrates and Vascular Function in Patients With Peripheral Artery Disease

The overarching question addressed in the current project is: Does dietary nitrate supplementation (8 weeks) improve physiological function in patients with peripheral arterial disease (PAD)? The investigators will specifically address whether dietary nitrate supplementation enhances blood vessel function, blood pressure regulation, and exercise capacity. The proposed project uses an array of clearly defined measurements which will allow investigators to quantify blood vessel function (vasodilator responsiveness and arterial stiffness), blood pressure (variability and responsiveness to stress), and functional capacity before and after 8 weeks of dietary supplementation.

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Key information

Conditions

Peripheral Artery Disease Arterial Occlusive Diseases Arteriosclerosis Atherosclerosis Behavior Cardiovascular Diseases Motor Activity Peripheral Arterial Disease Peripheral Vascular Diseases Vascular Diseases

Age range

50 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Iowa

Iowa City, Iowa, 52242, United States

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Documented peripheral artery disease
  • Ankle-Brachial Index (ABI) < or = to 0.90

Exclusion criteria

  • Non-atherosclerotic vascular disease
  • Critical limb ischemia
  • Active ischemic ulceration
  • Recent (within one year) revascularization
  • Symptomatic coronary artery disease (angina pectoris)
  • Heart failure
  • Resting systolic blood pressure > 180 mmHg or diastolic pressure > 100 mmHg
  • Hypotension (resting systolic BP < 90 mmHg)
  • Smoking or history of smoking within past one year
  • Use of phosphodiesterase V inhibitor drugs
  • Women with history of hormone replacement therapy within the past 6 months

Treatment and study plan

Sodium nitrate

Dietary Supplement

Sodium Nitrate (1g/day) for 8 weeks

Placebo

Other

Microcrystalline cellulose (daily) for 8 weeks

Primary outcomes

  1. Change in Vasodilator Capacity

    Time frame: Pre and post 8 weeks of dietary nitrate supplementation

    Forearm and calf blood flow will be measured independently by venous occlusion plethysmography using mercury-in-silastic strain gauges. Plethysmographic measurements will be made at rest and following 5 minutes of ischemia (reactive hyperemia) of the distal limb (forearm and calf). Peak blood flow will be determined as the highest flow recorded during the post deflation period. Total blood flow will be measured as the area under the time-curve after resting flow is subtracted. Vascular conductance will be calculated using blood flow/mean arterial pressure (via finger plethysmograph).

  2. Change in Arterial Stiffness

    Time frame: Pre and post 8 weeks of dietary nitrate supplementation

    ECG gated arterial waveforms will be obtained via applanation tonometry from the carotid and femoral arteries. The pulse wave velocity (PWV; index of arterial stiffness) will be determined between the carotid and femoral measurement sites (cfPWV). The time (t) between the feet of recorded pressure waves will be determined as the mean of 10 consecutive cardiac cycles. PWV is calculated from the distance (D; meters) between measurement points and the measured time delay (t): PWV = D/Δt (m/s).

  3. Change in Functional Capacity - Distance Walked in 6 Minutes

    Time frame: Pre and post 8 weeks of dietary nitrate supplementation

    6-minute walk tests will be performed before and after treatment to assess functional capacity. The main comparisons will be changes distance walked in 6 minutes after 8 weeks of dietary nitrate supplementation.

Sponsors and collaborators

Lead sponsor

University of Iowa

Other

Collaborators

  • American Heart Association

Registry information

Important dates

Study start
2013
Primary completion
2016
Study completion
2016
First posted
Nov 14, 2013
Registry last updated
Jun 3, 2019

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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