Although clinical incompatibilities of antihistamines and protamine with radiologic contrast media are well recognized, no report is available on the interaction of heparin, Coumadin, dextrans and other anticoagulants with these agents. We have employed the automated activated clotting time (ACT), prothrombin time (FT), partial thromboplastin time (PTT) and the thrombin time (TT) methods to monitor the anticoagulant actions of contrast media and its interaction with various anticoagulant drugs in patients undergoing angiography, A strong synergism of the anticoagulant action of heparin was observed in patients given heparin along with contrast media. Studies conducted in human volunteers revealed that contrast media at a 1-5 mg/ml level (clinical, 0.5-0.6 mg/ml) produce a strong synergistic effect on the anticoagulant action of heparin, oral anticoagulants, dextrans, and antiplatelet drugs. When blood obtained from patients undergoing angiography was supplemented with 0.25 u/ml heparin, the ACT, PTT and TT were equal to 1.5-2.0 units of heparin. Conventional amounts of protamine are incapable of neutralizing this synergistic interaction. These studies show that contrast media temporarily augments the degree of anticoagulation in patients undergoing angiography, which should be taken into consideration in patients undergoing vascular angiography.
Characteristics analysis of cerebral vascular angiography from transient ischemic attack accompanied with type 2 diabetes
