Thrombogenic Potential of Nonionic Contrast Media: Dr. King replies

Abstract

Dr. Robertson's commentary about the complex issue of thrombogenic potential of nonionic contrast media is timely and important when the appropriate use of the nonionic contrast agents is being discussed. The recent studies by Fareed, Hwang, and Kopko and their associates1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar, 2Hwang MH Piao ZE Murdock DK Messmore HL Giardina JJ Scanlon PJ Risk of thromboembolism during diagnostic and interventional cardiac procedures with nonionic contrast media.Radiology. 1990; 174: 453-457PubMed Google Scholar, 3Kopko PM Smith DC Bull BS Thrombin generation in nonclottable mixtures of blood and nonionic contrast agents.Radiology. 1990; 174: 459-461PubMed Google Scholar addressed the issue of the relative lack of anticoagulation that the nonionic contrast media seem to possess. Although most studies have dealt with in vitro situations, it is not unreasonable to be concerned about possible in vivo thrombogenic complications when these new nonionic agents are used, especially in coronary angiography and cerebral angiography. Also, one should be concerned when certain patients are already at high risk for thrombogenic complications. In the report by Fareed and colleagues,1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar certain risk factors for possible nonionic contrast media-induced thrombosis were identified (Table 1). In addition, Fareed and associates showed that thrombin generation was dramatically increased with use of nonionic contrast agents when glass syringes were used in angiography. Thus, their conclusion was that nonionic contrast media should be used only with plastic syringes.Table 1Risk Factors for Nonionic Contrast Media-Induced Thrombosis 1.Antithrombin III deficiency2.Protein C or protein S deficiency3.Hyperfibrinogenemia4.Thrombocytosis5.Increased factor VIII levels6.Hemoconcentration7.Hyperviscosity syndrome8.Paraproteinemias9.Leukemias (increase in number of leukocytes)10.Hemolysis11.Oral contraceptives and smokingFrom Fareed and associates1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar By permission of the Radiological Society of North America, Inc. Open table in a new tab From Fareed and associates1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar By permission of the Radiological Society of North America, Inc. In light of Dr. Robertson's commentary and studies that have been reported recently, it is apparent that the potential for thrombotic complications is higher with nonionic contrast agents than with ionic contrast agents. In addition, extreme care and meticulous technique should be used during angiography to prevent the mixing of blood and the contrast medium. It is now apparent that large-scale prospective clinical trials should be conducted to determine the clinical significance of the thrombogenic risk with nonionic contrast media. Until then, maintaining a continuous saline drip flowing through the intravascular catheter and systemic or local administration of heparin (or both) are two commonly used safety precautions that may provide an improved safety margin until further information is gained from future clinical studies. Thrombogenic Potential of Nonionic Contrast MediaMayo Clinic ProceedingsVol. 65Issue 4PreviewThe review article, “Low-Osmolality Contrast Media: A Current Perspective,” by King and associates in the August 1989 issue of the Proceedings (pages 976 to 985) provides a thoughtful overview of contemporary literature on the subject. The question of interaction of blood and low-osmolar contrast media (LOCM) and spontaneous formation of blood clots merits further comment, in light of recent articles in the radiologic literature. Full-Text PDF