Dietary Nitrates and Vascular Function in Patients With Peripheral Artery Disease

February 20, 2019 updated by: Darren P Casey, University of Iowa
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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

21

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Iowa
      • Iowa City, Iowa, United States, 52242
        • University of Iowa

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

50 years to 85 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Sodium Nitrate
Sodium Nitrate (1g/day) for 8 weeks
Dietary supplement: Sodium Nitrate
Sodium Nitrate (1g/day) for 8 weeks
Placebo Comparator: Placebo capsule
Microcrystalline cellulose (daily) for 8 weeks
Other: Placebo
Microcrystalline cellulose (daily) for 8 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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).
Pre and post 8 weeks of dietary nitrate supplementation
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).
Pre and post 8 weeks of dietary nitrate supplementation
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.
Pre and post 8 weeks of dietary nitrate supplementation

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Iowa

Collaborators

American Heart Association

Investigators

  • Principal Investigator: Darren P Casey, Ph.D., University of Iowa

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

November 1, 2013

Primary Completion (Actual)

June 30, 2016

Study Completion (Actual)

June 30, 2016

Study Registration Dates

First Submitted

October 28, 2013

First Submitted That Met QC Criteria

November 7, 2013

First Posted (Estimate)

November 14, 2013

Study Record Updates

Last Update Posted (Actual)

June 3, 2019

Last Update Submitted That Met QC Criteria

February 20, 2019

Last Verified

February 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 201307745
  • 13GRNT16490002 (Other Grant/Funding Number: American Heart Association)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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