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Â Title: Community-based walking exercise enhanced by Ankle-Foot Orthoses to improve walking ability for patients with Peripheral Artery Disease (AFO for PAD)
Â Authors: Ryan J. Mays, PhD, MPH,1,2,3 Ashley A. Mays, MD,2 Ryan L. Mizner, PhD1
Affiliations:School of Physical Therapy and Rehabilitation Science,1 College of Health Professions and Biomedical Sciences, University of Montana, and the International Heart Institute of Montana Foundation,2 Saint Patrick Hospital, Providence Medical Group, Missoula, MT; Division of General Internal Medicine,3 Department of Medicine, University of Colorado School of Medicine, Aurora, CO
Keywords: claudication;peak walking time; 6-min walk test; motion analysis; electromyography
Â Objective:Peripheral artery disease (PAD) occurs as the result of the development ofatherosclerotic plaque in the arteries of the lower limbs. The classic symptom of PAD is intermittent claudication (IC), defined by patients as pain, aching, and/or cramping in the leg muscles duringwalking which resolves with rest. Patients with PAD haveimpaired walking and functional abilityas well aspoor patient-reported outcomes.Novel orthotic devices have recently been developed to improve walking ability of other patient populationswith ambulatory impairments (e.g., those with stroke). We present the protocol for the ankle-foot orthoses (AFO) for PAD trial, an ongoing, open label,non-randomized study with the primary aim of evaluating whether AFO can improve the walking ability of PAD patients.
Setting:Single-center, outpatient ambulatory setting within the International Heart Institute and University of Montana.
Methods:We aim to recruit 15 PAD patientswho present with IC. Following device fittings by a certified orthotist, patients complete 2 baseline exercise tests on a graded treadmill within 1 week. In randomized order and investigators blinded to device exposure, patients complete one exercise test using the AFO and the second test without the use of the AFO.The primary outcome is peak walking time (PWT) between device exposure and no exposure to the device. Secondary outcomes(assessed at the same visits as the primary outcome) include the evaluation of claudication onset time (COT), functional ability via peak walking distance (PWD) from the 6-minute walk test, and peak oxygen consumption (VO2peak). Additionally, ankle power during propulsion and calf muscle recruitment areexamined with and without the AFO during walking. Exploratory outcomes include the effect of the AFO following 12 weeks of community-based exercise where upfront walking advice is provided (standard of care). Post-intervention outcomes include PWT, COT, functional ability, VO2peak, and patient-reported outcomes assessed with the Walking Impairment Questionnaire. Following the 12 week intervention, patients will participate in a focus group meeting todiscuss the barriers and facilitators to using the AFO for walking exercise.
Results:Three patients have been recruited thus far (20% of a priori-defined sample size) and 2 patients having completed baseline outcome assessments. Because investigators are blinded to whether or not patients complete the exercise tests with or without the AFO, we report only difference scores for thepeak walking ability outcomes between baseline exercise tests (PWT: Î”0.9Â±1.7 min; PWD: Î”42.9Â±126.0 feet).
Interpretation:Preliminary results indicate a numerical trend for minimal clinically important difference for PAD patients walking with and without the AFO. If AFO for PAD improves walking ability of patients with IC, the therapeutic implications of the device for treating the diseasewill have substantial impact and may serve as the basis for large randomized, controlled interventional trials.