This study will be a prospective, randomized study of patients with suggested predictors of TRA failure/difficulty referred for coronary angiography. Patients referred for coronary angiography using the trans-radial approach will be randomly assigned to obtain arterial access via the right or left radial artery. A registry of patients referred for coronary angiography using the trans-femoral approach will be compiled. The primary outcome measure will be radiation exposure as measured by dose area product output from the coronary angiography system. Secondary measures will include the total fluoroscopy time, total dose of radiation, number of catheters used, and incidence of subclavian tortuosity. In addition, procedural complications and success rates will also be evaluated.