Conditions: Peripheral Arterial Disease
Keywords: endothelium nitric oxide statins ascorbic acid
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 108
Healthy volunteers: no

Brief summary:
This study will seek to determine whether non-invasive measures of endothelial function have utility as surrogate markers of cardiovascular risk in patients with peripheral arterial disease undergoing vascular surgery. Measurements of endothelial function will be made before and after initiation of atorvastatin, ascorbic acid, or placebo therapy during the pre-operative period. We will then examine cardiovascular events following surgery. We hypothesize that patients who have no improvement in endothelial function will have increased cardiovascular risk compared to patients with improvement in endothelial function.

Detailed description:
Part 1 of the study will involve only patients with PAD who are undergoing non-cardiac surgery and is an intervention study. Part 2 will involve patients with PAD who have participated in Part 1 and patients with PAD who are not undergoing surgery. This part of the study does not involve an intervention.

The protocol for patients undergoing surgery is as follows: Part 1. Intervention study with follow-up for 30 days after surgery. Patients with planned surgery will be enrolled. We will test endothelial function at baseline using ultrasound and tonometry. They will then be randomzied to one of three groups: Atorvastatin 80 mg/d, Vitamin C 500 mg/d, or placebo. Subjects already on a statin medication at the time of enrollment will receive 40 mg/d of atorvastatin. Patients taking high dose statin (\>40 mg/day) will be randomized to received vitamin C or placebo, and will not be eligible to receive any additional statin as part of the study. In the week immediately prior to surgery, we will test endothelial function a second time. They will then be followed for 30 days beginning with the day of surgery for cardiovascular events. Part 1 of the study involves 4 visits as follows: Visit 1 at enrollment will take place within 7-30 days of non-emergent vascular surgery and will last approximately 60 minutes Visit 2 will take place within approximately 1 week of surgery and will last approximately 30-40 minutes Visit 3 will occur on the 1st post-operative day and will last approximately 10-15 minutes Visit 4 will take place only if the subject is still an in-patient. It will take approximately 10-15 minutes Telephone contact will occur at 30 days post surgery and every six months thereafter for two years. The duration of telephone follow-up is expected to be approximately 5-10 minutes. Part 2 (long term follow-up): Patients who have completed Part 1 will be continued on in Part 2 of the study. Part 2 involves two year follow-up with no study medication. Telephone contact will be made every 6 months. subjects will make a visit to our research unit one year after the initial visit for physical examination, and if applicable, an ultrasound study of their bypass grafts.

The protocol for patients with PAD who are not undergoing surgery is as follows. These patients will participate in Part 2 of the study only (long-term follow-up with no intervention). Visit 1: will last approximately 60 minutes and involve measurement of endothelial function by ultrasound and tonometry. We will contact the subject every 6 months by telephone (5-10 minutes) for two years to determine whether a cardiovascular event has occurred. Visit 2 will occur at 1 year post enrollment and will last approximately 20-30 minutes. If the subject has had peripheral bypass surgery, we will perform an ultrasound study to determine graft blood flow.

Arms:
arm 1: Atorvastatin 40 or 80 mg/day arm 2: Ascorbic Acid 500 mg/day arm 3: Placebo atorvastatin and Placebo ascorbic acid

Interventions: intervention 1: atorvastatin intervention 2: ascorbic acid intervention 3: Placebo
Intervention descriptions: intervention 1: atorvastatin 40 or 80 mg/day intervention 2: ascorbic acid 500 mg/day intervention 3: matching placebo

Protocol document: