Embolic problems in angiography.
All contrast agents, including the non-ionic variety, are anticoagulant and have antiplatelet effects. There is absolutely no evidence from any source, in vitro or in vivo, that non-ionic contrast agents have any "prothrombotic" or "procoagulant" or "thrombogenic" potential, as has been suggested in some quarters. They simply have a lesser anticoagulant effect than do the ionic agents old or new, which is entirely predictable and in line with their generally greater inertness and biocompatibility. Although there may still be scope for greater understanding of structure-toxicity relationships in contrast agent design, currently it is believed that it would be impossible to restore a stronger anticoagulant effect to a non-ionic contrast agent without simultaneously restoring other aspects of toxicity. The angiographer who calls for more anticoagulant contrast agents is calling for more toxic contrast agents. It has been our clinical experience, and that of many others throughout Europe, that there has been no increase in clinically apparent thromboembolic phenomena since the introduction of non-ionic agents. Furthermore, it has been our experimental experience that, although contrast agents of all kinds play a role (inhibitory) in thromboembolism, the role of other materials used by the angiographer are of greater importance. Thus, the materials of and, indeed, the method of preparation of, the catheters and guidewires used has a great bearing on the phenomenon. Heparinization of the patient should surely be beneficial in some cases, but there is, surprisingly, no firm consensus or data on this and the individual requirements of patients vary, necessitating some method of monitoring and control.(ABSTRACT TRUNCATED AT 250 WORDS)
Dawson
P
P
Department of Radiology, Hammersmith Hospital, London, England.
D000792:Angiography / Q000009:adverse effects*; D002404:Catheterization / Q000009:adverse effects; D003287:Contrast Media / Q000009:adverse effects; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D013923:Thromboembolism / Q000209:etiology* / Q000517:prevention & control
D003287:Contrast Media; D006493:Heparin