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).

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.

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.