Coagulation (Exam IV) Flashcards
What two factors are exposed by injury leading to platelet adherence & activation?
-Exposed Collagen
- Von Willebrand Factor
What type of thrombus is associated with a high pressure vessel (i.e. artery)?
White Thrombus (No RBCs, just fibrin)
What type of thrombus is associated with a low pressure vessel (i.e. vein)?
Red Thrombus (RBC + fibrin)
What do platelets release that. causes local vasoconstriction?
Serotonin
What type of thrombus would you expect to see associated with Coronary Artery Disease? Why?
White Thrombus (high pressure vessel, no RBCs)
Detachment of Red thrombi typically leads to what complication?
- Pulmonary Embolism
DVT risk factors can be _________ and/or _________.
- Inherited; acquired
What are some examples of inherited DVT risk factors?
- Antithrombin III deficiency
- Protein C or S deficiency
- Sickle Cell Anemia
- Activated Protein C resistance
What are some examples of acquired DVT risk factors?
- Bedbound
- Surgery/trauma
- Obesity
- Estrogen use (birth control typical)
- Malignancies
- chronic venous insufficiency
What common form of transportation is a risk factor for DVT formation? How is this prevented?
- Airplane flights
- Getting up, stretching, flexing lower extremities.
What is DIC? Why does this occur?
What results from this condition?
- Disseminated Intravascular Coagulation
- Completely used up blood clotting factors
- Excessive spontaneous bleeding is the result.
What are four common causes of DIC?
What are the treatments?
- Massive tissue injury
- Malignancy
- Bacterial Sepsis
- Abruptio Placentae
Plasma transfusion & treatment of underlying cause.
What is the mortality of DIC?
- 10-50%
How is overcoagulation avoided by our body’s internal mechanisms?
Regulation of Coagulation via:
- Fibrin Inhibition
- Fibrinolysis
What 4 protease inhibitors rapidly inactivate coagulation proteins?
- α1 antiprotease
- α2 macroglobulin
- α2 antiplasmin
- Antithrombin
What enzyme converts plasminogen to plasmin?
What is the purpose of this conversion?
- tPA (tissue Plasminogen Activator)
- Plasmin actually breaks down the clot itself
What drug protects a clot from lysis via plasmin?
- Aminocaproic acid
Which three enzymes potentiate the fibrinolytic process?
How do they accomplish this?
- t-PA
- Urokinase (produced in kidneys)
- Streptokinase
Conversion of plasminogen to plasmin.
What are the four groups of coagulation modifying drugs?
- Anticoagulants
- Antiplatelets
- Thrombolytic (Fibrinolytics)
- Hemostatic/Antifibrinolytics
Differentiate anticoagulants & antiplatelets.
- Anticoagulants - Inhibit action or formation of clotting factors thus preventing clot formation.
- Antiplatelets - Inhibit platelet aggregation thus preventing platelet plugs.
What is the prototypical parenteral anticoagulant drug & its general MOA?
What is the goal of therapy with this drug?
- Heparin = inactivation of clotting factors
- Goal = ↓ venous thrombosis
What is the prototypical oral anticoagulant drug & its general MOA?
What is the goal of therapy with this drug?
- Warfarin = ↓ synthesis of clotting factors
- Goal = ↓ venous thrombosis
What is the prototypical oral antiplatelet drug & its generalized MOA?
What is the goal of therapy with this drug?
- Aspirin - ↓ platelet aggregation
- Goal = ↓ arterial thrombosis
What is the prototypical thrombolytic drug?
Streptokinase
What drugs are indirect thrombin inhibitors?
What is their MOA?
- Unfractionated & fractionated forms of heparin
- Enhances anti-thrombin activity, inactivation of factor Xa, & inhibition of thrombin.
Differentiate unfractionated heparin, LMW heparin, & Fondaparinux.
- Unfractionated Heparin = ↑ Antithrombin III activity, binds to ATIII, Xa, & Thrombin.
- LMW Heparin = Binds to Xa, & ATIII
- Fondaparinux = binds to ATIII only (via pentasaccharide sequence)
What enzyme does heparin activate?
How much does heparin enhance this enzyme’s activity?
At what rate is the heparin consumed through this process?
- Antithrombin III (via conformational change)
- 1000x enhancement
- Heparin is not consumed by this process, only acts as a catalyst.