Coagulation and tests Flashcards
Components of the coagulation pathways ?
- Extrinsic
- Intrinsic
- Common
Intrinsic coagulation pathway?
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Coagulation?
- Vasospasm
- Platelet plug (Activation, stabilisation & inhibition)
- Coagulation (Initiation, fortification & inhibition)
- Fibrinolysis (Activation & inhibition)
Primary haemostasis ?
- Vasospasm
2. Platelet plug (Activation, stabilisation & inhibition)
Secondary haemostasis?
- Coagulation (Initiation, fortification & inhibition)
2. Fibrinolysis (Activation & inhibition)
Platelet ?
- Produced by megakaryocytes
- Stored in the spleen and liver
- Lifespan of 8-9 days
Vasospasm?
- Damage to tissue
- Collagen exposed with adherence of vWF
- Thrombocytes adherence to Von Willebrand factor (released from endothelium)
- The complex will secret Thromboxane A2 & Serotonin
- Vasospasm occurs
Platelet plug formation?
- Other platelete/vWF complexes bind together forming a clot.
- Inhibition - Nitric oxide & prostaglandins - of platelet activation
Coagulation cascade?
- Leaky endothelium
- Exposed tissue factor - Combine with factor VII & Calcium (Complex)
- Complex activates VII
- Activated complex with activate factor IX & X
- Activated FV & FXa will form a complex - activation of thrombin
Intrinsic pathways?
- Slower system
2. Leads to production of 95% of the thrombin
Inhibition of coagulation ?
- Antithrombin
- Protein C & S
- Tissue factor pathway inhibitor
Fibrinolysis ?
- Plasminogen is activated by tissue plasmin activator
Fibrinolysis ?
- Plasminogen is activated by tissue plasmin activator
2. PAI1 & 2 inhibitors
Vitamin K dependent clotting factors?
Factors : IX, X, VII and prothrombin, protein C, S and Z
clotting simpling
Citrate chelates calcium therefore placing it in pause
Prothrombin time ?
- Assesses the extrinsic and common pathway
2. Calcium is added to blood in the presence of TF & phospholipids
INR?
- This is a ratio of patient’s PT to control PT obtained using international reference thromboplastin reagent developed by WHO
- FII, VII, IX & X (PT & INR)
aPTT?
- Assesses the intrinsic and common pathways
2. Fibrinogen, prothrombin, FV, FVIII, FIX, FX, FXII
Thrombin time ?
Measures the final step in coagulation, the conversion of Fibrinogen to Fibrin.
TEG
Monitors the interaction between platelet within the fibrin mesh and lysis over time
FFP?
- Contains - All coagulation factors, fibrinogen, albumin, protein C, protein S, antithrombin and tissue factor pathway inhibitor.
- It is free of erythrocytes, platelets and leukocytes
Desmopressin?
- It is a vasopressin analogue
- Stimulates vWF - FVIII and tPA
- For dysfunctional platelets and some patients with haemophilia
Vitamin K ?
- Co-factor for many coagulation factors
2. FII, VII, IX, X, Protein C & S. Patients on warfarin or liver failure
Tranexamic acid?
- inhibits fibrinolysis by inhibiting plasminogen activation.
NOAC?
- Dabigatran - Thrombin inhibitor
2. Rivaroxaban - Factor Xa inhibitor
Others?
- Warfarin - Vitamin K antagonist
- ASA - COX1 inhibitor - Inhibits adhesion by thromboxane A2
- Clopidogrel - ADP receptor inhibitor - Inhibits adhesion by GP IIb/IIIa
Heparin?
- Naturally occuring glycosaminoglycan
- Binds to antithrombin
- Inactivates thrombin, Xa, IXa, XIa and XIIa
Alteplase ?
- Plasminogen activator
2. Promotion of fibrinolysis
ROTEM / TEG
Interpretation of the results. Reed them
