Improving Walking in Peripheral Artery Disease

Study Overview
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Brief Summary
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Peripheral artery disease (PAD) is a cardiovascular disease manifesting from systemic atherosclerosis that blocks the leg arteries and results in insufficient blood flow to the lower extremities. Limb ischemia from PAD is the most common disorder treated within the vascular surgical service of the Omaha Veterans Affairs Medical Center. PAD also accounts for one-third of the operations performed in the VA Medical Centers nationwide. The risk of mortality of Veterans with PAD is substantial; nearly 30% of Veterans with PAD died within 3.8 years of diagnosis. This project aims to establish the feasibility and acceptability of specially designed assistive shoes in patients with PAD and to determine if there are any potential benefits of using these shoes over standard shoes. These assistive shoes may enable patients to carry out desired activities of daily living with less pain and more physical activity. Increasing physical activity will decrease morbidity and mortality. If proven beneficial, the findings will lead to a novel and conservative rehabilitation protocol that directly benefits Veterans nationwide.

Detailed Description
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The long-term goal of this project is to improve mobility, functional independence, and quality of life in patients with peripheral artery disease (PAD) by using specially designed assistive shoes. PAD is a manifestation of systemic atherosclerosis producing blockages in the leg arteries, resulting in insufficient blood flow to the lower extremities. Limb ischemia from PAD is the most common disorder treated within the vascular surgical service of the Omaha Veterans Affairs Medical Center. PAD also accounts for one-third of the operations performed nationwide in the VA. Walking induced muscle pain known as intermittent claudication is the most common PAD symptom. Claudicating patients with PAD walk slower, have reduced quality of life and lose independence in performing activities of daily living. The investigators have identified consistent deficits of the ankle plantarflexors to effectively push-off during walking. Currently, there is a critical treatment gap for patients whose disease presentation does not warrant an operative approach, but who desire to restore their functional independence and walking ability. Specially designed assistive shoes (carbon fiber: CF; spring-loaded: SL) with specific mechanical properties to absorb and release energy, have been shown to promote push-off efficiency in walkers and runners. These shoes may lead to improved push-off in populations with reduced ankle push-off capacity, but this has not been tested yet. This work proposes to evaluate patient preferences in terms of using assistive shoes and whether these shoes improve walking performance in claudicating patients with PAD. The investigators hypothesize that assistive shoes (CF and SL) will lead to improved walking performance in patients with PAD as compared to standard shoes. The investigators also hypothesize that subject reported preference of assistive shoes (CF and SL) will be positive based on comfort, fatigue, ease of walking, and feasibility. These hypotheses will be tested by the following three specific aims: Aim 1: Determine the acute improvement in walking performance (claudication walking distances, vertical ground reaction force, and muscle oxygenation) in patients with PAD while using their standard shoes versus the assistive shoes. Aim 2: Determine the subject-reported preference of assistive shoes. Aim 3: Determine the progressive improvements in physical activity, quality of life, and walking distance after a three-month assistive shoe intervention. Twenty patients with PAD will be recruited for Aims 1 and 2. For Aim 1, each subject will walk on a pressure instrumented treadmill while performing a progressive treadmill test with a near infrared spectroscopy sensor on the calf for each shoe condition: i) standard, ii) CF, and iii) SL. Walking performance will be evaluated in terms of claudication walking distances, vertical ground reaction force, and muscle oxygenation. All outcomes will be compared across these three types of shoes. Aim 2 will primarily focus on qualitative measurements of subject reported preference to identify whether assistive shoes are feasible for patients with PAD to use. Visual-analog scales, rate of perceived exertion, and interviews will be used to assess comfort, fatigue, intensity, and feasibility after each condition of Aim 1. Five patients from Aims 1 and 2 who are satisfied with CL and another five who are satisfied with SL, will be recruited for Aim 3. Patients will wear the assistive shoes of their choice for regular daily use for three months as a conservative intervention. Physical activity, quality of life, and walking distances will be assessed prior to the start of the intervention and after three months of intervention. Overall, the aims will demonstrate feasibility and acceptability of assistive shoes in patients with PAD. Results will support a full clinical trial, and guide necessary intervention length and potential rehabilitation recommendations.

Official Title
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Improving Walking in Peripheral Artery Disease Using Specially Designed Assistive Shoes

Conditions
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Peripheral Artery Disease

Intervention / Treatment
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* Other: Assistive tennis shoes


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: At entry into the study, all patients must: be able to give written, informed consent demonstrate positive history of chronic claudication have an ankle brachial index < 0.90 at rest have a stable blood pressure regimen, stable lipid regimen, stable diabetes regimen and risk factor control for 6 weeks Exclusion Criteria: Any potential subjects will be excluded if they have: rest pain or tissue loss due to peripheral artery disease (Fontaine stage III and IV) acute lower extremity ischemic event secondary to thromboembolic disease or acute trauma walking capacity significantly limited by conditions other than claudication including leg (joint/musculoskeletal, neurologic) and systemic (heart, lung disease) pathology

Ages Eligible for Study
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Minimum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: Ten patients will wear assistive shoes for 3 months.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Progressive improvement in walking performance<br>A total of ten patients with peripheral artery disease will be enrolled for this arm and wear the assistive tennis shoes for three-months as an intervention. | Other: Assistive tennis shoes<br>* Assistive shoes include carbon-fiber and spring loaded shoes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in walking distance after three-months intervention | The investigators will measure absolute claudication walking distance from the Gardner treadmill test | Baseline and after three-months intervention | 
| Comfort level of wearing assistive shoe expressed as a numeric value and this value will be rated by participants | The investigators will ask the questions to participant that how comfort is the assistive shoes to wear. Participants will rate a number between 0 to 10. Zero represents 'Low comfort' and 10 represents 'High comfort'. | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in vertical ground reaction force after three-months intervention | The investigators will measure the vertical ground reaction force from pressure-instrumented treadmill | Baseline and after three-months intervention | 
| Changes in muscle oxygenation after three-months intervention | The investigators will measure the minimum muscle oxygenation during treadmill test | Baseline and after three-months intervention | 
| Changes in physical activity after three-months intervention | The investigators will calculate the average steps per day as a measure of physical activity using Actigraph accelerometer | Baseline and after three-months intervention | 
| Changes in Walking Impairment Questionnaire score after three-months intervention | Patients will complete the Walking Impairment Questionnaire. The investigator will calculate the score from the questionnaire. The score ranges from zero to hundred. Zero represents the worst health status and hundred represents the best health status. | Baseline and after three-months intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Peripheral artery disease