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Dietary Nitrates and Vascular Function in Patients With Peripheral Artery Disease

Primary Purpose

Peripheral Artery Disease

Status
Completed
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
Sodium Nitrate
Placebo
Sponsored by
University of Iowa
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional basic science trial for Peripheral Artery Disease focused on measuring nitrates, blood flow, vascular function, exercise

Eligibility Criteria

50 Years - 85 Years (Adult, Older Adult)All SexesDoes not accept healthy volunteers

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

Sites / Locations

  • University of Iowa

Arms of the Study

Arm 1

Arm 2

Arm Type

Experimental

Placebo Comparator

Arm Label

Sodium Nitrate

Placebo capsule

Arm Description

Sodium Nitrate (1g/day) for 8 weeks

Microcrystalline cellulose (daily) for 8 weeks

Outcomes

Primary Outcome Measures

Change in Vasodilator Capacity
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).
Change in Arterial Stiffness
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).
Change in Functional Capacity - Distance Walked in 6 Minutes
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.

Secondary Outcome Measures

Full Information

First Posted
October 28, 2013
Last Updated
February 20, 2019
Sponsor
University of Iowa
Collaborators
American Heart Association
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1. Study Identification

Unique Protocol Identification Number
NCT01983826
Brief Title
Dietary Nitrates and Vascular Function in Patients With Peripheral Artery Disease
Official Title
Dietary Nitrates and Vascular Function in Patients With Peripheral Artery Disease
Study Type
Interventional

2. Study Status

Record Verification Date
February 2019
Overall Recruitment Status
Completed
Study Start Date
November 2013 (undefined)
Primary Completion Date
June 30, 2016 (Actual)
Study Completion Date
June 30, 2016 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
University of Iowa
Collaborators
American Heart Association

4. Oversight

Data Monitoring Committee
No

5. Study Description

Brief Summary
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.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Peripheral Artery Disease
Keywords
nitrates, blood flow, vascular function, exercise

7. Study Design

Primary Purpose
Basic Science
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Masking
ParticipantInvestigator
Allocation
Randomized
Enrollment
21 (Actual)

8. Arms, Groups, and Interventions

Arm Title
Sodium Nitrate
Arm Type
Experimental
Arm Description
Sodium Nitrate (1g/day) for 8 weeks
Arm Title
Placebo capsule
Arm Type
Placebo Comparator
Arm Description
Microcrystalline cellulose (daily) for 8 weeks
Intervention Type
Dietary Supplement
Intervention Name(s)
Sodium Nitrate
Intervention Description
Sodium Nitrate (1g/day) for 8 weeks
Intervention Type
Other
Intervention Name(s)
Placebo
Intervention Description
Microcrystalline cellulose (daily) for 8 weeks
Primary Outcome Measure Information:
Title
Change in Vasodilator Capacity
Description
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).
Time Frame
Pre and post 8 weeks of dietary nitrate supplementation
Title
Change in Arterial Stiffness
Description
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).
Time Frame
Pre and post 8 weeks of dietary nitrate supplementation
Title
Change in Functional Capacity - Distance Walked in 6 Minutes
Description
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.
Time Frame
Pre and post 8 weeks of dietary nitrate supplementation

10. Eligibility

Sex
All
Minimum Age & Unit of Time
50 Years
Maximum Age & Unit of Time
85 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
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
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Darren P Casey, Ph.D.
Organizational Affiliation
University of Iowa
Official's Role
Principal Investigator
Facility Information:
Facility Name
University of Iowa
City
Iowa City
State/Province
Iowa
ZIP/Postal Code
52242
Country
United States

12. IPD Sharing Statement

Citations:
PubMed Identifier
35090799
Citation
Hughes WE, Treichler DP, Ueda K, Bock JM, Casey DP. Sodium nitrate supplementation improves blood pressure reactivity in patients with peripheral artery disease. Nutr Metab Cardiovasc Dis. 2022 Mar;32(3):710-714. doi: 10.1016/j.numecd.2021.12.002. Epub 2021 Dec 8.
Results Reference
derived

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Dietary Nitrates and Vascular Function in Patients With Peripheral Artery Disease

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