In a patient with suspected antithrombin III deficiency and heparin resistance, which product best replenishes antithrombin III?

In a patient with suspected antithrombin III deficiency and heparin resistance, which product best replenishes antithrombin III?

• A. Fresh frozen plasma
• B. Vitamin K
• C. Cryoprecipitate
• D. Platelets

Answer: (A)

Antithrombin III is the natural inhibitor that heparin works through. Heparin accelerates ATIII’s inhibition of thrombin and factor Xa, so when ATIII is deficient, the anticoagulant effect of heparin is blunted—this is heparin resistance. Fresh frozen plasma provides all coagulation factors, including antithrombin III, so giving FFP replenishes ATIII levels and restores heparin responsiveness. The other options don’t supply antithrombin III: vitamin K is for producing vitamin K–dependent factors, cryoprecipitate mainly contains fibrinogen and some other factors, and platelets don’t replenish ATIII.

Antithrombin III is the natural inhibitor that heparin works through. Heparin accelerates ATIII’s inhibition of thrombin and factor Xa, so when ATIII is deficient, the anticoagulant effect of heparin is blunted—this is heparin resistance. Fresh frozen plasma provides all coagulation factors, including antithrombin III, so giving FFP replenishes ATIII levels and restores heparin responsiveness. The other options don’t supply antithrombin III: vitamin K is for producing vitamin K–dependent factors, cryoprecipitate mainly contains fibrinogen and some other factors, and platelets don’t replenish ATIII.