6. Patients with risk factors of hypertension and cardiac disease may be enrolled in the study, provided that hypertension is medication controlled (supine diastolic BP < 95 mm Hg) and cardiac disease (e.g. angina pectoris, congestive heart failure, right bundle branch block, or arrhythmias) is stable on appropriate medication for 3 months prior to Screening. Peripheral vascular disease must have been stable for 3 months prior to Screening. No elective surgical procedures should be planned during the course of the study (e.g., vascular bypass procedures or coronary artery bypass surgery).