General Review of Hemostasis Fibrinolysis and Thrombosis

1. General Review of Hemostasis Fibrinolysis and Thrombosis 高志平 台北榮總 血液腫瘤科

3. Von Willebrand Disease • vWF: • enhance production of FVIII protect FVIII • binding platelet (GPIb/IX) and collagen in subendothelium • vWD • FVIII: low, prolonged aPTT • BT: prolonged • RIPA, ristocetin cofactor • Mild bleeding tendency Blood, Hadin et al, eds, 2003

4. Hematology, Hoffman et al, eds,2005

5. Laboratory Assays for vWD • Diagnosis • vWF Ag • vWF activity: ristocetin cofactor • FVIII activity (moderate and severe vWD) • BT (moderate and severe vWD) • aPTT: too insensitive • Molecular diagnosis: type II, exon 28 • Classification • RIPA • vWF multimers

6. Management of vWD • Reassurance • Cryoprecipitate • DDAVP • FVIII • vWF product

7. Extrinsic pathway Prothrombin time: adding tissue factor, Ca++

8. aPTT: activated partial thromboplastin time Partial thromboplastin: phospholipid, Ca++,lacking tissue factor

9. TFPI: tissue factor pathway inhibitor Hemostasis and Thrombosis 2005

10. Coagulation • Tissue factor initiate blood coagulation • TF express in adventitial cells, vascular smooth muscle cells, epidermal cells, neuroglia • TF express in monocytes and endothelium after activation • Amplification of the initial stimulus • FVIIa activate FIX • FIIa (thrombin) can activate XI, V, VIII • Feedback inhibition of the procoagulant system • TFPI: tissue factor pathway inhibitor • AT, PC, PS, EPCR

11. Thrombin can activate • Fibrinogen • FXI • FV • FVIII • FXIII • Protein C (after binding thrombomodulin) • TAFI (thrombin-activatable fibrinolysis inhibitor)

12. Factors synthesized in endothelial cells • vWF • Thrombomodulin • EPCR (endothelial protein C receptor) • Protein S • TFPI • tPA • PAI-1 • PGI2 (prostacyclin), NO (EDRF), CD39, ET-1

13. Common Causes of Prolonged PT • Deficiencies of FVII, X, V, II, fibrinogen • Elevated FDP • Heparin of high conc. • Coumadin • Lupus anticoagulant occasionally • Inhibitors of clotting factors

14. Vitamin K-dependent coagulation factors and anticoagulants • Factors II, VII, IX, X • Protein C, S • Protein Z (anti-Xa • (Not AT, Not TFPI, Not TAFI)

15. Hematology, Hoffman et al, eds,2005

16. Superwarfarin • Long-acting • Need high dose vitamin K • Potentially lethal

17. Common Causes of Prolonged aPTT • Clotting factor deficiencies other than FVII • Lupus anticoagulant • Inhibitors of clotting factors • Elevated FDP • Heparin, coumadin

20. Interpretation of Mixed aPTT • Definition of “correctable”: mixed aPTT – C : < 3-5” • Inhibitior with time-dependence after incubation

21. Mixinf aPTT • P: 60.5 C: 28.5 Mixed: 31.0 (o hr) • P: 64.5 C: 32.5 Mixed: 34.0 (2 hr) • P: 60.5 C: 28.5 Mixed: 56.0 (o hr) • P: 64.5 C: 32.5 Mixed: 60.0 (2 hr) • P: 60.5 C: 28.5 Mixed: 31.0 (o hr) • P: 64.5 C: 32.5 Mixed: 63.0 (2 hr)

22. FVIII inhibitor • P: 60.5 C: 28.5 Mixed: 34.0 (o hr) • P: 64.5 C: 32.5 Mixed: 60.0 (2 hr) • PNT : negative • FVIII inhibitor assay: 5 Bethesda unit • FVIII 5 % • FIX 90 % • FVII 110 %

26. Lupus anticoagulant • P: 60.5 C: 28.5 Mixed: 54.0 (o hr) • P: 64.5 C: 32.5 Mixed: 60.0 (2 hr) • PNT : + • FVIII inhibitor assay: negative • FVIII 90 % • FIX 90 % • FVII 110 %

27. Antiphospholipid syndrome • Anticardiolipin antibodies • Lupus anticoagulant • Antigen specificity: majority 2-GPI, prothrombin • Protein cofactor • Syphilis: not dependent on protein cofactor • Mechanisms of thrombosis • Disruption of annexin A5 shield • Interference protein C pathway • Injury to endothelium • …………. ?

28. Blood 1999;93:2153

30. Blood 1999;93:2153

31. Hematology Hoffman et al, eds, 2005

32. Causes of bleeding in APS • Hypoprothrombinemia • Severe thrombocytopenia • Acquired platelet dysfunction • Acquired inhibitor to specific coagulation factor, e.g. anti-FVIII

33. Lupus anticoagulant with low levels of cogaulation factor activity • P: 60.5 C: 28.5 Mixed: 56.0 (o hr) • P: 64.5 C: 32.5 Mixed: 60.0 (2 hr) • PNT: negative • FVIII inhibitor : negative • FVIII 10 % • FIX 16 % • FVII 50 %

34. Lupus anticoagulant with low level of cogaulation factor activity • P: 60.5 C: 28.5 Mixed: 56.0 (o hr) • P: 64.5 C: 32.5 Mixed: 60.0 (2 hr) • PNT: negative • FVIII inhibitor : negative • FVIII 4 % • FIX 60% • FVII 80 %

35. FVIII activities in serial dilutions • 1:10 3.5% • 1:40 7.6%(1.9% x 4) • 1:80 17.6%(2.2% x 8) • 1:160 48%% (3.0% x 16)

36. Therapy • No therapy for laboratory abnormality with clinical disorder • Anticoagulation for recurrent thrombosis • Low dose ASA and heparin for > = 3X pregnancy losses • Steroid for refractory cases

37. Thrombosis and Antithrombotic Therapy

38. Blood, Handin et al, eds, 2003

39. TTP • Thrombotic Thrombocytopenic Purpura • Mealloprotease (ADAMTS 13)  ultralarge multimers of vWF  platelet thrombi

40. TTP • Pentad: • thrombocytopenia • microangiopathic hemolytic anemia • fever • renal failure • fluctuating neurological symptoms • Management • Plasma exchange • Immunomodulation

41. NEJM 2002;347:596

42. Postgraduate Hematology 2005

43. Blood, Handin et al, eds, 2003

44. Serine protease • Canonical catalytic triad • His 57, Asp 102, Ser 195 by chymotrypsin number • FII, VII, IX, X, XI (NOT FV, FVIII, FXIII, fibrinogen, vWF) • Protein C (NOT protein S, AT) • Plaminogen, tPA (NOT PAI-I, TAFI)

45. Serpins • Serine protease inhibitor • Antithrombin • PAI-1, PAI-2 • PCI • Heparin cofactor II • 2-antiplasmin

47. FV Leiden and FV HongKong • FV Leiden: Arg506Gln APC resistance: APC sensitivity ratio • FV HongKong: Arg306Gla no increased risk of venous thrombosis • FV Cambridge: Arg306Thr

48. Hemostasis and Thrombosis, 5th ed, 2006

49. Postgraduate Hematology 2005