Peripheral artery disease is a disease that contributes to significant morbidity and mortality of millions of Americans yearly. Very little is known about the pathophysiology of atherosclerosis in peripheral artery disease. We plan to collect peripheral arteries and muscle tissue from patients undergoing amputation for end stage peripheral arterial occlusive disease. By extracting the RNA from these arteries and tissues and comparing them with RNA expression from normal arteries, we hope to have a better understanding of the pathophysiology of atherosclerosis in this setting. We aim to prove the hypothesis that a novel gene expression pattern can be discovered by the successful extraction of RNA from plaques from human peripheral arteries.

Patients scheduled to undergo lower extremity amputation will be consented for extraction of plaque from the carotid artery or arterial tissue from the amputated limbs. The surgeon will perform the amputation, then the harvest team will collect arterial tissue from amputated limbs. These samples will be immersed in RNALater solution to preserve the integrity of the RNA. Tissues will stored at -80oC in the RNALater until the RNA is later extracted using a standardized protocol. The RNA will be examined for quality using an Agilent bioanalyzer, and will then be processed on Affymetrix U133A chips for gene expression data. The data will be analyzed with the MATLAB software package.

Inclusion Criteria:

• Patients undergoing amputations for peripheral artery disease
• Patients undergoing free fibular transfer

Exclusion Criteria:

• those that are not able to consent to the study

Patients with peripheral artery occlusive disease.