Coagulation cascade ______________________________________ Coumadin inhibits: II, VII, IX, X, Proteins C,S [in brackets below] Protein C,S -> VIIIa, Va (+) (-) heparin -> ATIII -> IXa, Xa, XIa, XIIa thrombin (+) tPA, UK, SK -----> plasminogen ______________________________________ Intrinsic {PTT} Extrinsic {PT} (surface contact) (thromboplastin) {HMWK, PK} tissue factor: III XII -> XIIa l XI -> XIa \l/ [IX] -> IXa VIIa <- [VII] {Ca++ VIII + vWF} \ / [X] ----> Xa l {Va PL \l/ Ca++} Prothrombin [II] ---> Thrombin / {TM} Plasmin ------> Fibrin <-- I (-) / XIIIa stabilized fibrin ______________________________________ vWF = vonWillenbrand factor PL = phospholipid HMWK = high molecular weight kallikrien PK = prekallikrien plasma thromboplastic complement = IXa, X/Xa, VIII, vWF, Ca++ VIII and IX are sex linked Hemophilia A (VIII) and B (IX) Liver generates all coagulation proteins except VIII TT measures: fibrin -> stabilized fibrin ______________________________________ by Michael T. Milano, MD PhD MTMilano@yahoo.com www.geocities.com/MTMilano/palm/