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Risk of thromboembolism during diagnostic and interventional cardiac procedures with nonionic contrast media
M H Hwang1, Z E Piao, D K Murdock
1Department of Medicine, Loyola University Medical Center, Maywood, Ill.
Insights
Nonionic contrast media, particularly in catheter-steerable wire systems, increase blood clot formation and thromboembolism during angiography. Heparin effectively prevents these adverse events, especially with nonionic agents.
Area of Science:
- Cardiovascular Research
- Medical Device Technology
Background:
- Thromboembolism is a significant risk during angiographic procedures.
- Contrast media and catheter systems can influence blood clot formation.
Purpose of the Study:
- To compare the thrombogenicity of different contrast media and catheter systems.
- To investigate the role of heparin in preventing contrast-induced thromboembolism.
Main Methods:
- Canine blood was exposed to various contrast media (iohexol, iopamidol, ioxaglate, diatrizoate) in catheter-syringe and catheter-steerable wire systems.
- Clot formation was assessed with and without heparinization.
- Coronary angiography was performed on dogs with and without heparin to evaluate thromboembolism.
Main Results:
- Nonionic contrast media (iohexol, iopamidol) induced significantly more blood clot formation than ionic media, especially in catheter-steerable wire systems.
- Thromboembolism occurred in all nonheparinized dogs undergoing angiography with nonionic contrast media.
- Heparinized blood completely prevented clot formation in all tested systems.
Conclusions:
- Nonionic contrast media are more thrombogenic than ionic contrast media in a canine model.
- Catheter-steerable wire systems exacerbate clot formation with nonionic agents.
- Heparin administration is crucial for preventing thromboembolism associated with nonionic contrast media during angiography.
Abstract:
To investigate the relationship between clot formation and thromboembolism, canine blood was withdrawn into catheter-syringe or catheter-steerable wire systems containing either contrast medium or normal saline as used in debubbling techniques. The contrast media used were iohexol, iopamidol, ioxaglate, and diatrizoate. Without the use of heparin, after a 30-minute incubation, blood clots were harvested from all catheter-syringe systems except those with diatrizoate and from all catheter-steerable wire systems. Significantly more blood clot was harvested from the catheter-steerable wire system. With use of heparinized blood, no clot was found in any system. Twelve dogs that underwent coronary angiography were divided into two groups; one received heparin (5,000 IU) and the other did not. Thromboembolism occurred in all nonheparinized dogs that underwent angiography with iohexol or iopamidol but not in any other group. The authors found that in a dog model nonionic contrast media are more thrombogenic than ionic contrast media, especially in the catheter-steerable wire system. The blood clot in the catheters is associated with thromboembolism during angiography. The authors maintain that in this setting, blood clotting and thromboembolism with nonionic agents can be eliminated with heparin.