Home-based, high-intensity exercise improves walking performance in PAD
Adults with peripheral artery disease who participated in a high-intensity, home-based walking exercise program for 12 months experienced improvements in measures of walking impairment vs. low intensity and controls, a speaker reported.
Supervised walking exercise is first-line therapy for adults with lower-extremity PAD; however, few people with PAD participate in supervised exercise, Mary M. McDermott, MD, Jeremiah Stamler professor, professor of general internal medicine and geriatrics and professor of preventive medicine at Northwestern University Feinberg School of Medicine, said during a presentation at the virtual American Heart Association Scientific Sessions. High-intensity walking exercise is recommended for adults with PAD, but the ischemic leg pain induced by high-intensity walking may be a deterrent to exercise.
“An exercise intervention that induced ischemic leg symptoms significantly improved walking ability in people with PAD, while a low-intensity intervention that avoided ischemic leg symptoms did not improve walking ability,” McDermott told Healio. “This suggests that ischemic leg pain during exercise is needed to attain benefit from a walking intervention in people with PAD.”
Low vs. high intensity
For the LITE randomized clinical trial, researchers assigned 305 participants with PAD from four centers to one of three parallel groups for 1 year: low-intensity, home-based exercise (n = 116), high-intensity, home-based exercise (n = 124), or a control group (n = 65). The mean age of participants was 69 years, 48% of participants were women and 59% were Black. Participants in the two home-based exercise groups received weekly phone counseling with a coach and were instructed to exercise 5 days per week for up to 50 minutes per session, with intensity monitored with an accelerometer. Researchers instructed the low-intensity group to walk at a comfortable pace without ischemic leg symptoms; those in the high-intensity group were asked to walk at a pace that induced moderate to severe ischemic leg pain. Controls received weekly education via phone.
Primary outcome was 12-month change in 6-minute walk distance, comparing low intensity vs. high intensity and low intensity vs. controls. Secondary outcomes included 6-month change in 6-minute walk distance, 12-month change in treadmill walk time, and 6- and 12-month changes in participant-reported distance, speed and physical functioning scores.
Improved walking distance, speed
Researchers found that participants assigned to the low-intensity intervention performed significantly worse at 12-month follow-up for change in 6-minute walk distance compared with the high-intensity group (mean change, 11.69 m vs. 53.34 m; P < .0001). There was no between-group difference for change in 6-minute walk distance among the low-intensity participants and controls, McDermott said.
In assessing the trajectory of 6-minute walk distance change across the three groups, McDermott said those assigned to high intensity improved at 6 and 12 months compared with low intensity and controls, respectively. Those in the high-intensity group also improved maximal treadmill walking time compared with low intensity (mean change, 1.83 minutes vs. 0.71 minutes; P = .015); however, both the low- and high-intensity walking groups significantly improved Walking Impairment Questionnaire distance scores at 12 months vs. controls.
“The walking impairment questionnaire outcome measure assesses the degree to which the participants believe they are walking further distances more easily at 12-month follow-up,” she said. Both walking groups also self-reported improved walking speed at 12 months compared with controls.
McDermott noted the study had limitations; at 12 months, 18% of participants had dropped out, and there was an inability to collect treadmill data at study end due to the COVID-19 pandemic. Results may also not be generalizable to supervised treadmill exercise training in PAD, she said.
“These results support high-intensity, home-based walking exercise to improve both objective and subjective measures of walking impairment in PAD, relative to a control group,” McDermott said.
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McDermott MM, et al. Cardiovascular toolbox: Clots and claudication. Presented at: American Heart Association Scientific Sessions; Nov. 13-17, 2020 (virtual meeting).
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