Hemodynamics I Flashcards
What is an early sign of anasarca?
Periorbital edema
What are the three most common causes of cardiogenic pulmonary edema?
- Left ventricular failure 2. Myocardial infarction 3. Systemic hypertension
What are the features of interstitial pulmonary edema?
- Poorly defined pulmonary vessels 2. Visible lung fissures 3. Septal lines 4. Thick bronchial walls
What is the main feature of alveolar pulmonary edema?
Bilateral symmetric perihilar lung consolidation
What are the roles of PGI-2 and NO?
Inhibit aggregation
What is the role of ADP and TXA-2?
Released by platelets, mediate platelet aggregation
What is the role of thrombomodulin?
Converts thrombin to an anticoagulant
Which cell makes TPA?
Endothelial cell
Which molecules are cofactors for antihrombin?
Heparin-like molecules
vWF links platelets to the subendothelium via what surface molecule?
Gp1b
What is the role of platelet factor 4?
In platelet granules, binds and inactivates heparin
Does serotonin induce vasoconstriction or vasodilation?
Vasoconstriction
Prothrombin time tests which arm of the coagulation cascade?
Extrinsic
PT is prolonged by what compound?
Warfarin
Partial thromboplastin time tests which arm of the coagulation cascade?
Intrinsic
PTT is prolonged by what compound?
Heparin, hemophilia, antiphospholipid Ab
Which factors are involved in the intrinsic arm?
TENET - 12, 11, 9, 8, 10 (plus calcium and phospholipid)
What are the roles of antithrombin III?
- Directly inactivates thrombin and factors IXa, Xa, XIa, XIIa 2. Potentiated by heparin
What are the roles of Protein C?
- Inhibits (cleaves) cofactors Va and VIIIa 2. Decreases rate of clot formation 3. Requires activation 4. Enhanced by Protein S
What is the role of plasmin?
Breaks down fibrin
What are the roles of thrombomodulin?
- Activated by thrombin 2. Binds to thrombin to alter its conformation 3. Complex activates Protein C, which inhibits Va / VIIIa
What is the role of tissue pathway factor inhibitor?
Inhibits VIIa-TF complex (extrinsic arm)
What molecule inactivates free plasmin?
alpha-2 antiplasmin
Which substances can activate plasminogen?
- TPA (endothelial cells) 2. Urokinase (plasma, various tissues) 3. Streptokinase (bacterial product)
Does heparin dissolve clots that have already formed?
No
What is the mechanism of action of heparin?
Activates antithrombin III, and inhibits thrombin, factor IXa, and factor Xa
What is the mechanism of action of warfarin?
Interferes with vitamin K metabolism, stops blood from clotting within vessels, getting bigger, and breaking off
What are the vitamin K dependent clotting factors?
10, 9, 7, 2
Does warfarin have more of an effect on the intrinsic or extrinsic pathway?
Extrinsic
Which drug is a direct thrombin inhibitor?
Dabigatrin
Which drugs are direct factor Xa inhibitors?
Rivaroxaban and apixaban
Which drug is a tissue factor pathway inhibitor?
TFPI
Most patients with warfarin necrosis have low levels of what compound?
Protein C
What is the cause of heparin-induced thrombocytopenia?
Antibodies to heparin bind heparin / platelet factor 4 complex, activation of platelets leads to intravascular coagulation and low platelet counts
Bernard Soulier disease
Defect of platelet adhesion, lack of Gp1b
Glanzmann’s thrombasthenia
Defect of platelet aggregation, lack of GpIIb-IIIa
Thrombotic thrombocytopenia purpura
Antibodes directed against vWF cleaving protease ADAMTS-13 - thrombi form in small vasculature
Hemophilia A lacks what clotting factor? B? C?
A - VIII B - IX C - XI
What is the first step in DIC?
Activation of thrombin systemically
How is DIC measured?
- D-DIMERS - measures plasmin-cleaved insoluble cross-linked fibrin 2. Indirect measurement of plasmin and thrombin activiy
