Anticoagulants

Question 1

stages of hemostasis

Answer 1

vascular constriction limits blood flow to area of injury, platelets become activated by thrombin and aggregate at site of injury. Fibrinogen is responsible for stimulating platelet clumping.
Activates platelets release ADP and TXA2 which activate additional platelets, serotonin, phospholipids, lipoproteins, and other proteins important for coag cascade. Activated platelets change their shape to accommodate the formation of the plug. A fibrin mesh forms and entraps the plug. If it contains only platelets it is a white thrombus, if it contains red it is a red thrombus.
Plasmin will cause dissolution of the clot to allow issue repair

Question 2

adhesion of the platelets

Answer 2

damage to the endothelial surface> subendothelial collagen exposure
production/ release of vWF from endothelial cells.
vWF anchos platelets to subendothelial collagen vascular wall
Von Willebrands Disease most common inherited coagulation defect
teatment- DDAVP releases vWF from endothelial cells also can give FFP

Question 3

activation of platelets

Answer 3

prothrombin>thrombin IIa which activates platelets
chape change and release of mediators
TX2 and ADP promote platelet aggregation

Question 4

aggregation of platelets

Answer 4

TX2 and ADP uncover fibrinogen receptor (GPIIb/IIIa). THis allows fibrinogen I to bind to the receptor and further aggregate platelets. after platelets aggregate, fibrin in woven into platelets and cross-linked (water soluble> stable). Cross- linkage requires fibrin stabilizing factor (XIII)

Question 5

MOA of ASA and NSAIDS

Answer 5

COX 1 inhibition: reduction in TXA2 release

Question 6

clotting factors

Answer 6

all procoags are produced in the liver with the exception of the following: Tissue factor of Thromboplastin (III) released from traumatized cells. Ca++ (IV) diet and vWF vascular endothelial cells
Vitamin K dependent factors: II, VII, IX, X, protein C, and protein S

Question 7

factor 1

Answer 7

fibrinogen

Question 8

factor 2

Answer 8

prothrombin

Question 9

factor 3

Answer 9

tissue factor/ thromboplastin- vascular wall and extravascular cell membrane; released from traumatized cells

Question 10

factor 4

Answer 10

calcium- diet

Question 11

factor 5

Answer 11

proaccelerin

Question 12

factor 7

Answer 12

proconvertin

Question 13

factor 8c

Answer 13

antihemophiliac factor

Question 14

factor 8 vWF

Answer 14

vonwillebrands factor- vascular endothelial cells

Question 15

factor 9

Answer 15

christmas factor

Question 16

factor 10

Answer 16

stuart prower factor

Question 17

factor 11

Answer 17

plasma thromboplastin antecedent

Question 18

factor 13

Answer 18

hageman factor

Question 19

factor 13

Answer 19

fibrin stabilizing factor

Question 20

protiens

Answer 20

c and s

Question 21

extrinsic pathway

Answer 21

damage occurs from outside of vessel> triggers release of tissue factors> this comes in contact with factor 7
complexed with Ca++ on platelet> activates factor X
Tissue factor is the primary physiologic initiator of coagulation
measured by PT test

Question 22

You can buy an extrinsic pathway for

Answer 22

37 cents

Question 23

intrinsic pathway

Answer 23

initiated when there is trauma to the vessel itself or exposure of blood to collagen.
Activation of XII>XI>IX when complexed with on platelet surface with factor VIII:C and Ca++> factor X
Measured with PTT

Question 24

you can buy the intrinsic pathway for

Answer 24

$12 or $11.98

Question 25

Common pathway

Answer 25

activation starts with factor X>V>II>I>XIII
thrombin converts fibrinogen I to fibrin and in the presence of XIII, fibrin cross linking occurs
the clot is now formed

Question 26

antithrombin 3

Answer 26

produced in the liver and neutralizes the final common pathway factors IIa & Xa and intrinsic factors IX, XIa, and XIIa
strongly inhibits factors IIa and Xa
partially inhibits factors IXa, XIa, and XIIa
Required cofactor for Heparin
heparin binds to antithrombin !!! and enhances AT !!! by 1000 times

Question 27

drugs that inhibit clotting factor synthesis

Answer 27

warfarin

Question 28

drugs that inhibit thrombin

Answer 28

heparin, lepirudin

Question 29

antiplatelet drugs

Answer 29

ASA- inhibits cyclooxygenase; duration of action is life of platelet (due to the covalent bond sharing of electron
NSAIDS_ same as ASA but the depression of TXA2 is shorter 24-48 hours
Ticlid, PLAVIX, and Persantine- inhibits ADP
Integrilin, Reopro, Aggrastat- anti-fibrinogen receptor (GPIIb/IIIa)

Question 30

thrombolytics

Answer 30

tPa, streptokinase

Question 31

antofibrinolytics

Answer 31

aprotinin(not used), Amicar used in CPB and acute hemorrhage

Question 32

heparin

Answer 32

binds/activates antithrombin III which then inhibits the serine proteases of the coag cascade. Heparin is abundant in granules of the mast cells that line vasculature. In response to injury heparin is released and inhibits coags. Heparin is also present in basophils and liver

Question 33

Coumadin

Answer 33

inhibits the vitamin K- dependent y-carboxylation reactions necessary to the function of thrombin, and factors II, VII, IX, and X as well as protein C

Question 34

ASA

Answer 34

inhibiting the activity of cyclooxegenase, aspirin reduces the production of thromboxane (TXA2). ASA also reduces endothelial cell production of prostacyclin, an inhibitor of platelet aggregation and a vasodilator. Since endothelial cells regenerate active cyclooxygenase faster than platelets. the net effect of ASA is more in favor of endothelial cell mediaated inhibition of the coag cascade.

Question 35

ReoPro, Integrellin, Aggrastat

Answer 35

glycoprotein IIb/IIIa inhibitors in the membrane of platelets, inhibit platelet aggregation. used in Acute Coronary Sydrome in ACLS protocol.