Hemostasis

Coagulation Cascade

Extrinsic and Intrinsic pathway are different ways to get to factor 10

Common pathway starts at 10

Get to 10 to get to 1

Done Clotting (anticoagulation)

  • Prostacyclin ⊣ aggregation

  • Plasminogen ➔ plasmin ➔ degrades fibrin

  • Antithrombin ⊣ 10, 9, 2 (thrombin) & activates tissue plasminogen activator (tPA)

    • Heparin potentiates antithrombin

  • Protein C+S (Vit-K reqd) deactivate 5 & 8 ➔ clot break

    • Warfarin ⊣ synthesis of C+S, 2,7,9,10

    • STOPPING/STARTING warfarin ➔ MORE 5 + 8 ➔ ↑ clots! (hypercoag state)

      • Warfarin initially decreases protein C (an anticoagulant) faster than the coagulation factors

      • Can paradoxically ↑ coagulation when first starting tx ➔ thrombosis ➔ skin necrosis & gangrene

    • Factor 5 mutation is a mutation that ➔ C/S resistance (C/S can't break down clotting factor 5) ➔ ↑ clotting