Systemic heparinization significantly decreases the complications of angiography due to thrombosis. Effective systemic heparinization is achieved by a combination of the direct intra-arterial injection of heparin through the catheter at the onset of the procedure and flushing intermittently with a dilute solution of heparinized saline. No increase in hemorrhage at the puncture site is noted due to this method of anti-coagulation. Certain precautions must be observed because of the larger doses of heparin employed.