AbstractPercutaneous coronary arteriography has been associated with numerous reports of embolic complications. Efforts to minimize such complications have focused upon normal hemostatic functions and the possible preventative role of systemic heparin. In considering the source and prevention of catheter emboli it is useful to review the mechanisms by which particulate matter may be introduced into the aortic root and to recognize that foreign material unaffected by anticoagulation may constitute a significant source of emboli. A simple technical protocol described in this communication has been followed during 3,500 percutaneous transfemoral coronary arteriograms using the Judkins approach. During this experience no embolic complications have been observed.