Radiographic contrast media and the coagulation and complement systems

Area of Science:

• Pharmacology
• Immunology
• Hematology

Background:

• Intravascular contrast agents can cause side effects impacting hemostasis and complement systems.
• These alterations are implicated as a primary cause of adverse contrast agent reactions.
• Both ionic and nonionic contrast media have been shown to activate the plasma kallikrein and complement cascade.

Purpose of the Study:

• To investigate the effects of intravascular contrast agents on hemostasis and complement systems.
• To elucidate the mechanisms underlying adverse contrast agent reactions.
• To assess the risk of thromboembolism associated with contrast media use during angiography.

Main Methods:

• In vitro and in vivo studies were conducted to evaluate contrast agent effects.
• Plasma kallikrein activation, factor XII contact phase, and bradykinin generation were assessed.
• Complement cascade activation via classic and alternative pathways was examined.
• Blood coagulation and clot formation in the presence of contrast media were analyzed.

Main Results:

• Contrast media activate plasma kallikrein, leading to bradykinin generation and complement cascade activation.
• In non-reactors, these alterations are transient; in reactors, they are more pronounced with reduced C1-esterase inhibitor.
• Contrast agents influence blood coagulation, potentially modifying thromboembolism risk during angiography.
• Ionic contrast agents may be more effective in inhibiting clot formation than nonionic agents.

Conclusions:

• Intravascular contrast agents significantly impact hemostasis and complement systems.
• Alterations in these systems are critical factors in adverse contrast agent reactions.
• Patients with pre-existing hemostatic or complement system abnormalities may be at higher risk.
• Understanding these effects is vital for managing risks of adverse reactions and thromboembolic complications in angiography.