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.

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:

1. IPC of the arms prevents DVT in legs;
2. Nitric oxide released by vascular endothelial cells exerts protective effects on blood vessels;
3. IPC increases nitric oxide availability locally in the lower extremity;
4. 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.

Category 1 subjects-healthy volunteers (no MRI required) INCLUSION (N-12) 21 -40 years male or female EXCLUSIONS History of CAD, MI, Cath,CABG,CTA, positive stress test HTN uncontrolled (SBP>140 or DBP>90) DM except diet controlled Cholesterol >200 at screening Smoking last 10 years Acute Medical Illness Inflammatory Phlebitis Infection lower limbs Recent lower limb surgery

Category 2 subjects ( age matched without CAD)(no MRI required) INCLUSION (N-12) 50 plus male or female EXCLUSIONS History of CAD, MI, Cath,CABG,CTA, positive stress test HTN uncontrolled (SBP>140 or DBP>90) DM except diet controlled Cholesterol >200 at screening Smoking last 10 years Acute Medical Illness Inflammatory Phlebitis Infection lower limbs Recent lower limb surgery

Category 3 subjects ( age matched with CAD)(no MRI required) INCLUSION (N-up to 5) 50 plus male or female documented CAD by cath, PTCI, CABG, CTA EXCLUSIONS History of CHF, DVT, PE Angina, active, needing nitrates Acute Medical Illness Inflammatory Phlebitis Infection lower limbs Recent lower limb surgery

Category 4 subjects with MRI (original group) INCLUSIONS(N=12) 50 plus male or female documented CAD by cath, PTCI, CABG, CTA EXCLUSIONS History of CHF, DVT, PE Angina, active, needing nitrates Atrial Fib BMI>35 (MRI) MRI contraindications pregnancy Chronic Inflammatory Disease Acute Medical Illness Inflammatory Phlebitis Infection lower limbs recent lower limb surgery