Coagulation Factors, Pathways, and Clinical Implications

Factor I

Fibrinogen

Factor II

Pro-thrombin

Factor III

Tissue Thromboplastin (TT)

Factor IV

Calcium

Factor V

Labile factor (proaccelerin)

Factor VI

Unassigned

Factor VII

Stable factor (proconvertin)

Factor VIII

Anti-hemophilic factor A (AHF)

Factor IX

Christmas Factor

Factor X

Stuart - Prower Factor

Factor XI

Plasma Thromboplastin antecedent

Factor XII

Hageman factor

Factor XIII

Fibrin Stabilizing factor

Serine protease inhibitors

All factors are serine protease inhibitors except: V, VIII, XIII

Which factors are coenzymes:

V, VII

Vitamin K dependent factors

II, VII, IX, X

Coagulation Requirements

Platelet factor-3, tissue thromboplastin, calcium

Coagulation Triggers

Tissues thromboplastin (TF), foreign surfaces, amniotic fluid, collagen

Intrinsic Pathway

(XII,XI,IX,VIII)

Independent of the extrinsic pathway

4-6 minutes, pTT

Extrinsic Pathway

(III, VII)

Tissue trauma causes the release of TF, beginning this pathway

Dependent on some factors and proteins within the intrinsic pathway

30 seconds, pT

Common Pathway

(X, V, II, I)

Begins with the formation of a prothrombinase complex by Xa, Va, AND Ca2+.

Thrombin

Cleaves fibrinogen into fibrin.

Thrombin activates XIII, and XIIa binds with calcium to help with fibrin cross linking.

Fibrinolysis

Endothelium expresses protein Tissue Plasminogen Activator (TPA), converts plasminogen to plasmin.

Plasmin breaks down fibrin mesh into fibrinogen and fibrin split products.

ASA

Decrease TXA2 release.

Clopidogrel, Prasugrel, Ticagrelor

Decrease ADP release.

Abciximab

Inhibits GP2b/3a inhibitors.

Von Willebrand Disease

Decreased vWF production.

Hemophilia A

Decreased VIII.

Hemophilia B

Decreased IX.

Hemophilia C

Decreased XI.

Heparin and factor X inhibitors

Decrease X (Rivaroxaban).

Heparin and factor II inhibitors

Decrease thrombin (Digatraban).

Warfarin

Decreases formation of all vitamin K dependent factors (II, VII, IX, X).

TPA drugs

Increased conversion of plasminogen to plasmin, given to stroke patients.

Increased D Dimer assay

Indicates increased clot breakdown.

Antifibrinolytics

TXA decreased plasminogen to plasmin, decreased breakdown of clot.