Clinical Research Directory

Inclusion Criteria: 1. history of claudication assessed by the Walking Impairment Questionnaire, 2. ambulatory leg pain in either one or both legs consistent with intermittent claudication confirmed during a screening graded treadmill test using the Gardner-Skinner protocol, 3. an ABI \<= 0.90 at rest or \> 20% decrease in ankle systolic blood pressure in either one or both legs immediately following the treadmill exercise test. 4. age \>= 60 years. Exclusion Criteria: 1. absence of PAD (ABI \> 0.90 at rest and ankle systolic blood pressure \< 20% decrease after exercise, 2. inability to obtain an ABI measure due to non-compressible vessels (ABI \> 1.40), 3. asymptomatic PAD (Fontaine Stage I) determined from the medical history and verified during the graded treadmill test, 4. rest pain due to PAD (Fontaine stage III) 5. tissue loss due to PAD (Fontaine stage IV) 6. use of medications indicated for the treatment of intermittent claudication (cilostazol and pentoxifylline) initiated within three months prior to investigation, 7. peripheral revascularization within one month prior to investigation, or peripheral revascularization performed during the study, 8. exercise tolerance limited by any disease process other than PAD, 9. active cancer, 10. kidney failure defined as stage 5 chronic kidney disease, 11. a calf skin fold measurement \> 25 mm, because of potential interference with the light path of the NIRS probe from penetrating the subcutaneous tissue, 12. pulse arterial oxygen saturation of the index finger \< 95% because of potential deleterious effect on calf muscle StO2 from poor pulmonary gas exchange, and 13. failure to complete the baseline run-in phase within three weeks.