Coagulation/Anticoagulation and Hemorrhagic/Thrombotic Disorders Flashcards
Ability of the body to stop bleeding from a damaged vessel and to repair the defect such that normal blood flow to the involved area is restored
Hemostasis
__ domain contains N-terminal domain of all polypeptides
E
______ can also bind IXa (less affinity) to form a TFPI-IXa-TF-VIIa complex
TFPI
______ can bind to Xa at its active site, and the TFPI-Xa complex inactivates TF-VIIa
TFPI
______ cleaves fibrinogen and fibrin to form FDP (Fibrin Degradation Products)
Plasmin
______ cleaves fibrinogen to fibrin and activates XIII to XIIIa
Thrombin
______ is a cofactor for APC cleavage of Va and VIIIa.
Protein S
______ is the only Vitamin-K dependent factor that is not a serine protease
Protein S
______ on the platelet surface interact with collagen, laminin, and fibronectin
Beta-1 integrins
______ removes basic amino acids from the C-terminal end of fibrin, reducing plasminogen binding sites on fibrin
Thrombin-activatable fibrinogen inhbitor (TAFI)
_______ consists of central globule (__ domain) and globules on each end of the molecule (__ domains)
Fibrin, E, D
_______ activates V and VIII to Va and VIIIa
Thrombin
_______ cleaves and inactivates factors Va and VIIIa, resulting in decreased thrombin production
APC
_______ covalently crosslinks adjacent D domains to stabilize/strengthen the clot
XIIIa
_______ Factor adheres to exposed, damaged, subendothelium
von Willebrand
_______ hemostasis: activation of clotting cascade and formation of fibrin clot
Secondary
_______ hemostasis: platelet adhesion, aggregation, and activation
Primary
_______ increases release of vWF from endothelium
Arginine vasopressin
_______ inhibits extrinsic part of coagulation pathway/initiation phase
Tissue Factor Pathway Inhibitor (TFPI)
_______ is resistant to proteolytic action of APC
Factor V Leiden
_______ measures the extrinsic pathway
PT
_______ measures the intrinsic pathway
PTT/APTT
________: antibodies interfere with function of phospholipid-binding proteins involved in regulation of coagulation
Antiphospholipid Antibody Syndrome
_______: can lead to heparin resistance because heparin is a cofactor for antithrombin
Antithrombin Deficiency
_______: IgG antibody against phospholipid in the platelet membrane, causing Antiphospholipid Antibody Syndrome (APS)
Lupus Anticoagulant
_______: internal membrane tunnels though which contents of granules can be released
Canalicular System
_______: leads to elevated concentration of plasma prothrombin, autosomal dominant inheritance
Prothrombin mutation
_______: leads to partial resistance to inactivation via Protein C proteolytic cleave
Factor V Leiden
_______: mutation in Factor V with an autosomal dominant inheritance pattern
Factor V Leiden
______: activated reaction of plasma with an anionic substrate
APTT
______: addition of tissue thromboplastin to initiate clotting
PT
______: key cofactor for antithrombin, accelerating its rate of protease inactivation by 102-106 fold
Heparin
______: serine protease produced in endothelial cells that is used to activate plasmin
Tissue Plasminogen Activator (t-PA)
______: serpin that binds and inactivates t-PA (also activated u-PA)
Plasminogen Activator Inhibitor-1 (PAI-1)
_____: serpin that binds and inactivates plasmin in a 1:1 ratio
Alpha-2 antiplasmin
Activators of Plasmin
t-PA, u-PA
Antithrombin targets factors: ______.
II, Xa, kallikrein, XIIa, XIa, IXa, VIIa-TF complex
APC cleaves and inactivates factors ___ and ___, resulting in decreased thrombin production
Va, VIIIa
Arterial or Venous Thrombus? Composed of aggregated platelets, containing small amounts of fibrin and blood cells
Arterial
Arterial or Venous Thrombus? Composed of large amounts of fibrin and numerous red cells
Venous
Arterial or Venous Thrombus? Occur under conditions of high shear stress
Arterial
Arterial or Venous Thrombus? Red Thrombus
Venous
Arterial or Venous Thrombus? Slow Blood flow
Venous
Arterial or Venous Thrombus? White Thrombus
Arterial
Circulating platelets adhere via _______ on the platelet surface and vWF
glycoprotein 1b (GP1b)
Cofactor Factors
III, V, VIII, HMWK (High Molecular Weight Kininogen)
Diagnostic Tool: in vitro bleeding time measurement, can determine platelet response to agonists
PFA-100
Diagnostic Tool: measures activity of fibrinogen and sensitive to heparin or fibrin split products
Thrombin Time
Diagnostic Tool: measures entire pathway, but more sensitive to intrinsic pathway: especially XI, VIII, and IX
APTT
Diagnostic Tool: measures platelet and vessel interaction, number of platelets, and function of platelets
Bleeding Time
Diagnostic Tool: most commonly prolonged by vitamin K deficiency, liver disease, or warfarin/rat poison ingestion
PT
Diagnostic Tool: normally 9-12 seconds, but standardized to an international normalized ratio (INR) that is reported
PT
Diagnostic Tool: prolonged with heparin contamination, fibrinogen deficiency, or abnormal fibrinogen
Thrombin Time
Diagnostic Tool: used to dianose Lupus anticoagulant
Russel’s Viper Venom Test (dRVVT)
Diagnostic Tool: used to monitor heparin therapy
APTT
Diagnostic Tool: used to monitor Warfarin therapy
PT
DIC shows a prolonged __ with less prolongation of the _____.
APTT, PT
Diganostic Tool: prolonged in Hemophilia A and B, XI or XII deficiency, Acquired hemophilia, von Willebrand Disease, Heparin, Lupus Anticoagulant
APTT
Drugs: administered subcutaneously and has longer half life than heparin
Low Molecular Weight Heparins (LMWH) and Fondaparinux
Drugs: antibodies to Platelet Factor 4/heparin complexes result in activation of platelets and a prothrombotic state
Heparin-Induced Thrombocytopenia/Thrombosis Syndrome (HIT)
Drugs: anticoagulant with rapid absorption with good bioavailability and long half-life
Warfarin
Drugs: binds to antithrombin III, and as a cofactor increases rate of thrombin inactivation by scale factor of 1000
Heparin
Drugs: complications associated with heparin therapy
Bleeding, Heparin-Induced Thrombocytopenia Syndrome (HIT), Allergic events
Drugs: complications/contraindications of warfarin (3)
Hemorrhage, Pregnancy contraindication, food/drug interactions
Drugs: direct thrombin inhibitors, used for patients with HIT
Argatroban (Novastan) and Lepirudin (Refludant)
Drugs: fibrinolyitc, used for acute myocardial infarction, ischemic stroke, DVT, pulmonary embolism
t-PA, u-PA, streptokinase
Drugs: full antithrombotic effect not achieved until existing coagulation factors in circulation are removed (3-5 days)
Warfarin
Drugs: inhibitors block GPIIb/IIIa receptor and prevent platelet aggregation
Abciximab, Eptifibatide, Tirofiban
Drugs: inhibits enzymes that use Vitamin K as a cofactor
Warfarin
Drugs: occurs naturally in mast cell granules; extracted from porcine intestine for therapeutic use
Heparin
Drugs: oral antiplatelet agents that bind to ADP receptor on platelets, and block activation by ADP
Thienopyridines
Drugs: oral ATP analogue that binds reversibly to ADP receptor
Ticagrelor
Drugs: permanent damage to platelet (it cannot synthesize new proteins) via inhibition of cyclooxygenase
Aspirin
Drugs: produced by chemical or enzymatic depolymerization of heparin to one-third the size of heparin
Low Molecular Weight Heparins (LMWH)
Drugs: recombinant form of a leech anticoagulant
Lepirudin (Refludant)
Drugs: selectively binds and inactivates factor Xa by antithrombin
Low Molecular Weight Heparins (LMWH) and Fondaparinux
Drugs: small molecule direct thrombin inhibitor
Argatroban (Novastan)
Drugs: synthetic pentasaccharide corresponding to minimal sequence required for heparin-like action
Fondaparinux
Drugs: treatment and prevention of venous thrombosis, pulmonary embolism, acute myocardial infarction, surgery requiring bypass, etc.
Heparin
Extrinsic Tenase Factor Components
III, VIIa, IX or X, Ca and phospholipid
Extrinsic Tenase Factor Products
IXa and Xa
Factor Deficiency: autosomal recessive inheritance with greater incidence in Ashkenazi population, prolonged PTT
XI
Factor Deficiency: autosomal recessive, rare, prolonged PTT
VII
Factor Deficiency: Hemophilia A and B, level defined by amount of residual factor activity, X-linked
VIII, and IX
Factor Deficiency: prolonged bleeding time and PTT, decreased Factor VIII
vWF
Functions of von Willebrand Factor VWF
Carrier protein for Factor VIII, platelet adhesion
In a one to one mixing study in a Lupus anticoagulant patient, the PTT is ______.
prolonged
In Lupus anticoagulant, the PTT can be resolved by adding _______.
excess phospholipid
Intrinsic Tenase Factor Components
IXa, VIIIa, X, Ca and phospholipid
Intrinsic Tenase Factor Products
Xa
Lack of _______ leads to VIII deficiency since, _______ is a carrier for VIII
vWF
Lack of ________ leads to abnormal platelet-endothelial interaction, leading to bleeding disorder of mucosal regions and skin
vWF
Liver disease shows a prolonged with less prolongation of the _____.
PT; APTT
Lupus anticoagulant shows an ______ PTT
prolonged
Methods of Treating ITP
Steroids, IVIG, Splenectomy
Mixing Studey (0, 2 hours): Normal, Normal
Hemophilia A
Mixing Studey (0, 2 hours): Normal, Prolonged
Acquired Factor VIII Antibody
Mixing Studey (0, 2 hours): Prolonged, Prolonged
Lupus Anticoagulant
Name all factors activated by thrombin.
XI, IX, VIII, V, XIII, and I
Neonatal purpura fulminans: homozygote for _________.
Protein S or Protein C
Platelet _____ granules acid hydrolases
lysosomal
Platelet ______ granules: proteins, especially fibrinogen, V, von Willebrand factor, as well as platelet activation factors and platelet growth factors
alpha
Platelet integrin _______ increases affinity for vWF
GPIIb-IIIa
Point mutation in Factor V that changes glutamine to arginine
V Leiden
Prothrombinase Components
Xa, Va, II, Ca and phospholipid
Prothrombinase Products
IIa
PT measures the _______ pathway.
Extrinsic
PTT/APTT measures the _______ pathway.
Intrinsic
Rate of activation of X to Xa is 50-100 times faster by the _____ tenase complex.
intrinsic
Serine Protease Factors
Prekallikrein, XII, XI, IX, X, VII, II
TFPI can also bind ____ (less affinity) to form a TFPI-____-TF-VIIa complex
IXa; IXa
TFPI can bind to ____ at its active site, and the ____ complex inactivates _____.
Xa; TFPI-Xa; TF-VIIa
Thrombin activates ________ in the amplification phase of clotting.
V and VIII
Thrombin binds to thrombomodulin on endothelial cells, creating a complex that can bind _______.
Protein C
Thrombin cleaves off _________ and _________, exposing sites on E domain that aligns complimentarily with D domain on another fibrin molecule
Fibrinopeptide A, Fibrinopeptide B
Treatment of vWF deficiency
Arginine vasopressin, Factor Replacement
Vitamin K dependent Factors
II, VII, IX, and X (Protein C and S)
VWD Stage __: abnormal clearance by platelets
IIb
VWD Stage __: partial quantitative deficiency
I
VWD Stage __: qualitative deficiency
II
VWD Stage __: severe or total quantitative deficiency
III
XIIIa can covalently link _______ to fibrin to stabilize the clot
α2-antiplasmin