OBJECTIVES: To prospectively compare the efficacy and procedural safety of the radial versus femoral route for cardiac catheterization during uninterrupted warfarin therapy.BACKGROUND: The optimal treatment strategy for cardiac catheterization in patients receiving long-term oral anticoagulation has not been defined. Increasing evidence suggests the feasibility and safety of catheterization without warfarin interruption. However, the relative safety and efficacy of the radial and femoral access in fully anticoagulated patients are unknown.METHODS: Fifty-six consecutive patients on chronic warfarin treatment with international normalized ratio (INR) between 1.8 and 3.5 were randomized to undergo coronary angiography, alone, or followed by percutaneous coronary intervention (PCI), via the femoral (n = 29) or radial route (n = 27). Procedural success, in-hospital major adverse cardiac and cerebrovascular events, access-site, and bleeding complications were recorded.RESULTS: The two groups were well balanced with similar clinical characteristics at baseline. There were no significant differences in preprocedural antiplatelet therapy or in INR levels between the radial and femoral group (2.62 ± 0.7 vs. 2.48 ± 0.6, respectively, P = 0.63). Procedural success was achieved in all femoral patients, whereas one patient in the radial group (3.7%) required crossover to femoral access. Eight patients from the femoral and 10 patients from the radial group successfully underwent PCI. Access-site complications occurred only in patients who underwent PCI: three (37.5%) in the femoral versus none in the radial group (P = 0.034).CONCLUSION: The radial access is as efficacious and safe as the femoral route for coronary angiography in fully anticoagulated patients, but is likely to result in fewer access-site complications in patients who also undergo PCI.