Effect of Cilostazol Endothelial Progenitor Cells and Collateral Formation in Peripheral Occlusive Artery Disease (PAOD)

1. titration of drugs 1. run-in period: eligible subjects are screened and baseline blood samples are obtained 2. study period: 12 weeks * 24 subjects with cilostazol and 20 subjects with dummy placebo * On the first day after the end of the study period, the follow-up data are obtained by the same procedure 3. blood sampling and measurement of serum biomarkers * obtained from peripheral veins in all study subjects at the run-in period and the end of the treatment period of the study * sent for isolation, cell culture, and assays of human EPCs * also stored for enzyme-linked immunosorbent assay (Stromal cell derived factor-alfa1, adiponectin, soluble thrombomodulin, vascular endothelial growth factor) 2. assays of human EPCs 1. colony formation by EPCs 2. quantification of EPCs and apoptotic endothelial cells 3. chemotactic motility, proliferation/viability and apoptosis assays 3. collateral vessels formation and distal run-off assessed by dual-energy multi-slice computed tomography angiography 4. echocardiographic examinations to evaluate left ventricular functions