Intermittent pneumatic compression (IPC) of the lower extremities is a well-established technique for preventing deep vein thrombosis (DVT) and for treating venous stasis.~Four categories of discoveries suggest that there may be potential of IPC to have global vascular benefits:~IPC of the arms prevents DVT in legs;~Nitric oxide released by vascular endothelial cells exerts protective effects on blood vessels;~IPC increases nitric oxide availability locally in the lower extremity;~Nitric oxide may be transported in blood and released at distant sites, particularly in a hypoxic setting. Therefore, we propose to test the effects of lower extremity IPC on global nitric oxide availability.~We will enroll 4 categories of subjects.~The first 3 categories will have only 1 hour of leg compression. Baseline cholesterol will be drawn for screening labs Brachial ultrasound and NO measurements will be done before and after 1 hr of IPC. No MRI will be done on these groups.~Category 4 will have baseline labs and testing to include:~Brachial ultrasound,NO measurements and MRI will be done before and after 4 weeks of daily IPC therapy.~Category 1, 21-40 yrs healthy male or female~Category 2, 50 yrs plus healthy males or females~Category 3, 50 yrs plus aged matched controls with known heart disease~Category 4, 50 yrs plus12 patients with coronary artery disease.
Intermittent pneumatic compression (IPC) of the lower extremities is a well-established technique for preventing deep vein thrombosis (DVT) and for treating venous stasis. IPC will be done in the home for 3 divided hours every day for 4 weeks. Lab tests, brachial ultrasound and MRI testing will be performed at baseline and after 4 weeks of daily IPC therapy.~See detailed description for increase in healthy control subjects.