Hetastarch interferes with coagulating through interacting with which coagulation factor?

Hetastarch interferes with coagulating through interacting with which coagulation factor?

• A. Antithrombin III
• B. Factor VIII
• C. Fibrinogen
• D. Protein S

Answer: (B)

Hetastarch, a synthetic colloid, can impair coagulation beyond simple dilution by reducing activity of a specific clotting factor. It tends to decrease factor VIII activity, which is a crucial cofactor for the intrinsic pathway to generate thrombin. When FVIII activity falls, the tenase complex (FVIIIa with FIXa) is less effective, thrombin generation drops, and clot formation is weakened. Factor VIII is tightly linked to von Willebrand factor, so changes in FVIII activity contribute to a coagulopathy seen with hetastarch use. While dilution can affect other components like fibrinogen, the question points to the factor most directly impacted, making FVIII the best-fit target.

Hetastarch, a synthetic colloid, can impair coagulation beyond simple dilution by reducing activity of a specific clotting factor. It tends to decrease factor VIII activity, which is a crucial cofactor for the intrinsic pathway to generate thrombin. When FVIII activity falls, the tenase complex (FVIIIa with FIXa) is less effective, thrombin generation drops, and clot formation is weakened. Factor VIII is tightly linked to von Willebrand factor, so changes in FVIII activity contribute to a coagulopathy seen with hetastarch use. While dilution can affect other components like fibrinogen, the question points to the factor most directly impacted, making FVIII the best-fit target.