Vascular endothelial growth factor (VEGF) gene therapy may be useful for the treatment of lower-limb ischemia. The objectives of this study were to evaluate safety and angiographic and hemodynamic responses of local catheter-mediated VEGF gene therapy in ischemic lower-limb arteries after percutaneous transluminal angioplasty (PTA). For this study, we recruited patients with chronic lower-limb ischemia and atherosclerotic infrainguinal occlusion or stenosis suitable for PTA. In the study, 18 patients received 2x10(10) plaque-forming units (pfu) VEGF-adenovirus (VEGF-Ad), 17 patients received VEGF-plasmid/liposome (VEGF-P/L; 2000 microg of VEGF plasmid, 2000 microl of DOTMA:DOPE), and 19 control patients received Ringer's lactate at the angioplasty site. Digital subtraction angiography (DSA) was used to evaluate vascularity before, immediately after, and 3 months after the PTA. Clinical follow-up data, basic laboratory tests, and ankle-brachial index (ABI) were evaluated. Primary endpoint was DSA analysis of vascularity, and secondary endpoints were restenosis rate, Rutherford class, and ABI after 3 months follow-up. No major gene transfer-related side effects or differences in laboratory tests were detected between the study groups. However, anti-adenovirus antibodies increased in 61% of the patients treated with VEGF-Ad. For the primary endpoint, follow-up DSA revealed increased vascularity in the VEGF-treated groups distally to the gene transfer site (VEGF-Ad P=0.03, VEGFP/L P=0.02) and in the VEGF-Ad group in the region of the clinically most severe ischemia (P=0.01). As for the secondary endpoints, mean Rutherford class and ABI showed statistically significant improvements in the VEGF-Ad and VEGF-P/L groups, but similar improvements were also seen in the control patients. We conclude that catheter-mediated VEGF gene therapy is safe and well tolerated. Angiography demonstrated that VEGF gene transfer increased vascularity after PTA in both VEGF-Ad- and VEGF-P/L-treated groups.