Ankle-foot Orthoses for Peripheral Artery Disease

Efficacy of Ankle-Foot Orthoses on Walking Ability in Peripheral Artery Disease: The AFO for PAD Trial I

The primary aim of this study is to investigate the effect of an ankle foot orthoses (AFO) on the primary outcome of peak walking time (PWT) in patients with peripheral artery disease (PAD).

Study Overview

• Status: Completed
• Conditions: Peripheral Artery Disease
• Intervention / Treatment: Device: AFO to improve outcomes

Detailed Description

The investigators will test the hypothesis that PAD patients using an AFO during a graded exercise test will demonstrate a greater PWT compared to PWT assessed without the use of an AFO. Secondary hypotheses include evaluation of the effect of an AFO on: 1) calf muscle function, 2) claudication onset time, 3) functional ability, 4) peak oxygen consumption, and 5) patient-reported outcomes. We will also examine the effects of the AFO on outcomes following 12 weeks of community walking.

• Study Type: Interventional
• Enrollment (Actual): 31
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Montana
    • Missoula, Montana, United States, 59802
      • International Heart Institute of Montana Foundation

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Men and women diagnosed with atherosclerotic peripheral arterial disease (PAD).
• Patients who experience calf claudication
• ≥40 years of age
• An abnormal ankle-brachial index (ABI) of ≤.90.
• For patients with an ABI >.90 and <1.00, a post-exercise ABI drop of 15% or more compared to the resting ABI

Exclusion Criteria:

• Lower extremity amputation(s) which interfere(s) with walking.
• Critical limb ischemia (i.e., ischemic rest pain, ulcers/gangrene on the lower extremities).
• Non-atherosclerotic PAD (e.g., popliteal entrapment syndrome, Takayasu's arteritis)
• Major surgical procedures that are contraindicated to an exercise program (e.g., recent organ transplant) or coronary artery bypass graft within 6 months prior to screening.
• Primarily limitations to exercise due to chronic obstructive pulmonary disease, angina or heart failure.
• Myocardial infarction within 3 months prior to screening.
• Acute coronary syndrome symptoms diagnosed at time of screening.
• Significant ischemic changes (documented on the 12-lead electrocardiogram) with horizontal or down-sloping ST-segment depression ≥ 0.5mm at rest and >1 mm with exercise in 3 beats for 2 contiguous leads, relative to the PR-segment (or ST-segment elevation ≥1mm).
• Transient ischemic attack or stroke 3 months prior to screening.
• New left bundle branch block or sustained ventricular tachycardia >30 seconds during screening.
• Uncontrolled hypertension defined as ≥180 systolic or ≥100 diastolic resting blood pressure during screening.
• Women who are pregnant (women of childbearing potential, a pregnancy test will be performed at screening.
• Individuals currently incarcerated.
• Evidence of acute impairment from alcohol or other illicit drugs.
• Lack of diabetes control (glycated hemoglobin >12%)
• Patients who are anemic (Hgb <11 g/dL for women and <10 g/dL for men).
• Any other clinically significant diseases (e.g., pulmonary, renal, psychiatric, immunological) that are not stabilized or may otherwise confound the results of the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: AFO to improve outcomes; Patients completed graded treadmill testing, followed by 12 weeks of unstructured community-based walking using the AFO ad libitum	Device: AFO to improve outcomes; Ankle foot orthoses (AFO) are light-weight, low profile carbon fiber devices that store and release energy during ambulation. The AFO, in combination with standard of care advice to walk more, will be used to determine if there is any improvement in PAD patient outcomes.
No Intervention: Historical Controls; Historical PAD control group (n = 10) received upfront advice to walk at home with no intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in WIQ Distance Subscore	In the Walking Impairment Questionnaire distance subcategory, participants are asked to rate the degree of difficulty walking specific distances on a scale from 0 to 4. A score of 0 indicates the inability to walk the distance specified by the question while a score of 4 represents no difficulty. The graded sub-score is multiplied by a pre-specified weight for each sub-category: distance, speed, and number of flights of stairs. The products of these subscores are summed and divided by the maximum possible score to obtain a percent score, ranging from 0 (inability to perform item) to 100 (no difficulty in performing item).	12 weeks
Change in WIQ Speed Subscore	In the Walking Impairment Questionnaire speed subcategory, participants are asked to rate the degree of difficulty walking one block at specific speeds, ranging from walking slowly to jogging, on a scale from 0 to 4. A score of 0 indicates the inability to walk the distance specified by the question while a score of 4 represents no difficulty. The graded sub-score is multiplied by a pre-specified weight for each sub-category: distance, speed, and number of flights of stairs. The products of these subscores are summed and divided by the maximum possible score to obtain a percent score, ranging from 0 (inability to perform item) to 100 (no difficulty in performing item).	12 weeks
Change in WIQ Stair-Climbing Subscore	In the Walking Impairment Questionnaire stair-climbing subcategory, participants are asked to rate the degree of difficulty climbing a specified number of stair flights, ranging from 1 to 3 stair flights, on a graded scale of 0 to 4. A score of 0 indicates the inability to climb the flights specified by the question while a score of 4 represents no difficulty. The graded sub-score is multiplied by a pre-specified weight for each sub-category: distance, speed, and number of flights of stairs. The products of these subscores are summed and divided by the maximum possible score to obtain a percent score, ranging from 0 (inability to perform item) to 100 (no difficulty in performing item).	12 weeks
Change in SF-36 PCS	Change in Medical Outcomes Study Short Form 36-item questionnaire, Physical Component Summary The SF-36 has eight scaled subscores (Vitality, Physical functioning, Bodily pain, General health perceptions, Physical role functioning, Emotional role functioning, Social role functioning, Mental health). These subscores are weighted sums of the questions in each section. Scores range from 0 - 100. Lower scores = more disability, higher scores = less disability.	12 weeks
Change in SF-36 MCS	Change in Medical Outcomes Study Short Form 36-item questionnaire, Mental Component Summary The SF-36 has eight scaled subscores (Vitality, Physical functioning, Bodily pain, General health perceptions, Physical role functioning, Emotional role functioning, Social role functioning, Mental health). These subscores are weighted sums of the questions in each section. Scores range from 0 - 100. Lower scores = more disability, higher scores = less disability.	12 weeks

Collaborators and Investigators

• Sponsor: University of Minnesota
• Collaborators: National Institutes of Health (NIH); National Institute of General Medical Sciences (NIGMS)
• Investigators: Principal Investigator: Ryan J. Mays, PhD, MPH, MS, International Heart Institute of Montana Foundation

Publications and helpful links

General Publications

• Mays RJ, Mays AA, Mizner RL. Efficacy of ankle-foot orthoses on walking ability in peripheral artery disease. Vasc Med. 2019 Aug;24(4):324-331. doi: 10.1177/1358863X19831765. Epub 2019 Mar 29.

Helpful Links

• Click here for more information about the sponsor

Study record dates

Study Major Dates

• Study Start: November 1, 2014
• Primary Completion (Actual): December 1, 2017
• Study Completion (Actual): December 1, 2017

Study Registration Dates

• First Submitted: October 28, 2014
• First Submitted That Met QC Criteria: October 28, 2014
• First Posted (Estimate): October 31, 2014

Study Record Updates

• Last Update Posted (Actual): July 31, 2019
• Last Update Submitted That Met QC Criteria: July 9, 2019
• Last Verified: July 1, 2019

More Information

Terms related to this study

• Keywords: claudication; ankle foot orthoses; community walking exercise
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Atherosclerosis; Peripheral Vascular Diseases; Peripheral Arterial Disease
• Other Study ID Numbers: Mays-2; U54GM104944 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED