Peripheral arterial disease may affect as many as 20 percent of persons older than 70 years. Stewart and colleagues review the use of exercise training for management of claudication, a common symptom of peripheral arterial disease that is characterized by walking-induced pain in the legs. A commonly used office-based measure to corroborate the presence of claudication is an abnormal ankle-brachial index, which compares the ratio of systolic blood pressure at the ankle and elbow.
A number of prospective studies have demonstrated benefits from exercise training in the treatment of claudication. The degree of improvement in pain-free walking is similar to or even greater than that occurring after revascularization. The greatest benefit has been shown in exercise programs that continued for at least six months, lasted at least 30 minutes per session and three times a week or more, and involved walking until near-maximal pain was reached.
There are several physiologic mechanisms by which exercise training may improve peripheral arterial disease. Animal models have demonstrated increased collateral vessel formation and increased blood flow with exercise training. At the microenvironment level, exercise has been shown to increase production of nitric oxide and other endothelial vasodilating factors. Blood viscosity decreases with exercise, and muscle oxidative capacity improves.
The authors present specific recommendations for an “exercise prescription” to be used by physicians for their patients with claudication (see the accompanying table). Given the likelihood of comorbid conditions in patients with peripheral arterial disease, the authors recommend testing for occult cardiac ischemia with an exercise treadmill test before beginning a walking program, although they also note that serious adverse effects from these programs are rare.
In patients with progressive claudication symptoms despite exercise training, the review suggests considering use of medications or revascularization procedures.