Daily ambulatory activity monitoring in patients with peripheral artery disease

Background: Peripheral artery disease (PAD) is characterized by arterial lesions of the lower extremities. Patients with PAD present ambulatory dysfunction due to intermittent claudication, limiting daily physical activity and increasing morbidity. Therefore, objectively measured daily ambulation is a clinically relevant outcome in these patients. Objective: To quantify daily ambulation with a step activity monitor (Step Watch 3^™; Cyma Inc., Mountlake Terrace, WA, USA) in patients with PAD. Major findings: Patients with claudication ambulate less each day than controls, as they take 1081 fewer strides (1 stride=2 steps) and spend 48 fewer minutes ambulating each day. The cadence obtained during endurance ambulation (maximum cadences for 60, 30, and 20 continuous minutes of ambulation) and short bouts of ambulation (maximum cadence for continuous minutes of ambulation and for the minute having the single highest cadence value each day) is also lower in patients. Demographic factors and comorbid conditions, particularly sex, dyslipidemia, abdominal obesity, and the number of components of metabolic syndrome, affect the ambulatory activity patterns of patients with claudication. Conclusions: Patients with claudication perform a lower amount of daily ambulatory activities and lower intense physical activities than controls, which is impaired further by comorbid conditions. The clinical implication is that patients with claudication should not only be advised to walk more during each day, but to do so at a cadence that is higher than their self-selected slower cadence. This approach will increase total daily exercise volume by increasing both the duration as well as the intensity of ambulation.