Ischemic Preconditioning Claudication Study

Walking Capacity of Patients With Claudication in Lower Extremities Following Ischemic Preconditioning

This study proposes ischemic preconditioning (IPC) as a novel intervention to improve walking distance in patients with intermittent claudication.

This study proposes ischemic preconditioning (IPC) as a novel intervention to improve walking distance in patients with intermittent claudication. Peripheral arterial disease (PAD) is a circulatory condition in which large supply blood vessels narrow, reducing oxygen and nutrient distribution to peripheral tissues. IPC protects against tissue damage caused by ischemia and can improve functional capacity in patients recovering from stroke; however, the benefit of ischemic preconditioning in patients with peripheral arterial disease remains unclear. The investigators predict that ischemic preconditioning (IPC) will delay claudication onset time (COT), increase peak walking time (PWT) and improve muscle strength in patients with intermittent claudication. The investigators will determine whether IPC improves claudication onset time (COT) and peak walking time (PWT) in patients with intermittent claudication. A motorized treadmill will be employed to assess COT and PWT. The investigators will determine whether IPC can improve muscle strength and time to pain onset in the affected leg of patients with intermittent claudication. These metrics will be assessed quantitatively using a Biodex™ dynamometer.

Intermittent Claudication, Ischemia Vascular, Peripheral Arterial Disease, Peripheral Vascular Disease

A standard blood pressure cuff will be placed on the right or left thigh, depending on the affected side, to occlude blood flow. The cuff will be inflated to 225 mmHg to prevent blood flow. Each session will consist of 4 cycles of 5 minute IPC applications, followed by 5 minutes of reperfusion for a total of 35 minutes.

The sham intervention protocol will be identical to the IPC protocol except blood flow to the affected leg is unchanged as cuff pressure will be raised to between the venous and diastolic pressures

Subjects will perform muscle contractions for muscle groups of interest (knee extensors/flexors and dorsiflexors/plantarflexors). Contractions will be measured in newton-meters. The duration will be determined by the time subjects first feel pain and when the pain becomes too great to continue. The investigators will provide subjects with visual feedback on the monitor throughout the testing.

Subjects will be placed on a motorized treadmill and claudication onset time will be recorded in seconds.

Inclusion Criteria: between ages of 18-80 able to give informed consent presence of vascular disease with intermittent claudication Exclusion Criteria: age < 18 or >80 unable to give informed consent presence of vascular disease with leg pain at rest, ischemic ulceration, or gangrene pregnancy unable to walk on a treadmill unable to perform or tolerate ischemic preconditioning unable to follow commands exercise capacity limited by symptoms of angina, congestive heart failure, chronic obstructive pulmonary disease, or arthritis to be determined by PI patients who have undergone vascular surgery or endovascular surgery in the previous year on the affected leg history of major lower extremity amputation history of major psychiatric disorder history of uncontrolled hypertension