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.
