Anti-thrombotics

Question 1

What is the only anti-thrombotic treatment difference between STEMI and NSTEMI?

Answer 1

Thrombolytics (only for STEMI)

Question 2

Which protease is responsible for converting fibrinogen to fibrin?

Answer 2

Thrombin

Question 3

What cocagulation cascade protein is responsible for degradation of fibrin clots?

Answer 3

Plasmin

Question 4

What is the length of platelet life span?

Answer 4

7-10 Days

Question 5

What is hemostasis?

Answer 5

Process that prevents blood loss from damaged blood vesses

Question 6

What is thrombosis?

Answer 6

Pathological formation of a hemostatic plug within the vasculature in the absence of bleeding

Question 7

What causes thrombosis?

Answer 7

Injury to blood vessel wall
Altered blood flow
Abnormal coagulability of blood

Question 8

What is the point of convergence for the intrinsic and extrinsic pathways?

Answer 8

Activation of Factor X to Factor Xa

Question 9

What activates plasminogen to plasmin?

Answer 9

t-PA (tissue plasminogen activator)

Question 10

What does GPIIb/GPIIIa do?

Answer 10

Glycoprotein receptor that binds fibrinogen on the platelets?

Question 11

What does P2Y1/P2Y12 do?

Answer 11

Purinergic receptors for ADP, stimulates COX and GPIIb/IIIa

Question 12

What does COX do (in respect to thrombogenesis)?

Answer 12

Production of TXA2/PGI2

Question 13

What is the only drug that can actually lyse a clot?

Answer 13

t-PA: Alteplase

Question 14

Why do we do fibrinolytic therapy in STEMIs?

Answer 14

Restore coronary blood flow, limit myocardial damage, better survival and fewer complications

Question 15

What is the mechanism of t-PA?

Answer 15

Transforms plasminogen to plasmin

Question 16

When should you try to administer thrombolytics by?

Answer 16

Within 30 minutes of patient’s presentation at hospital

Question 17

What are adverse effects of thromobolytics?

Answer 17

Bleeding is most common complication

Streptokinase can result in systemic lytic state - interfering with coagulation in general circulation

Question 18

What are contraindications to thrombolytics?

Answer 18

Roughly 30% of patients may be unsuited
Situations where drug therapy could impair necessary clots within circulation (Peptic ulcer, recent stroke, surgery recovery)

Question 19

Why do we not give heparin orally?

Answer 19

It is too large and too negative, needs parenteral delivery.

Question 20

Which drug inhibits coagulation independently of antithrombin?

Answer 20

Bivalirudin

Question 21

What is the only drug recommended for chronic angina?

Answer 21

Aspirin

Question 22

What are the names of all the heparins/heparin-like drugs?

Answer 22

Unfractionated heparin
LMWH (Enoxaparin, Dalteparin)
Fondaparinux

Question 23

What is the major unique side effect of UFH?

Answer 23

Heparin-induced thrombocytopenia (HIT)

Question 24

Why are LMWH preferred?

Answer 24

Less risk of HIT

Fondaparinux also confers this advantage

Question 25

What does bivalirudin act on? | What do heparins act on?

Answer 25

Bivalirudin: Acts on both circulating and clot-bound-thrombin Heparins: Circulating thrombin

Question 26

What indication for bivalirudin?

Answer 26

Unstable angina undergoing percutaneous coronary intervention.

Question 27

What is the major adverse effect of bivalirudin?

Answer 27

Bleeding

Question 28

What is the mechanism of aspirin?

Answer 28

Irreversibly acetylates COX1 in platelet, blocks thromboxane | Also encourages endothelial cells to produce prostacyclin (prevents platelet adhesion)

Question 29

``` What are the thienopyridines? What do the thienopyridines do? Which thienopyridines are reversible? Which are irreversible? What is the advantage of reversible ones? ```

Answer 29

Clopidogrel (Irrev), ticlopidine (Irrev), prasugrel (Irrev), ticagrelor (Rev) Block P2Y1 and P2Y12 to prevent ADP-mediated activation of platelets Reversibles are advantageous for patients who need to go to surgery, platelets restore function earlier

Question 30

Which thienopyridines need to be metabolized to be activated? Which one needs CYP2C19 and what co-administration is a concern for it?

Answer 30

Clopidogrel, ticlopidine, and prasugrel | Clopidogrel requires CYP2C19 and care should be taken if co-administered with omeprazole (PPIs inhibit CYP2C19)

Question 31

What side-effects are associated with thienopyridines? | What are the advantages and disadvantages of them versus aspirin?

Answer 31

In general bleeding and GI, ticlopidine associated with life threatening neutropenia and thrombotic thrombocytopenic purpura Superior monotherapy to aspirin in reducing MI risk, but more expensive and higher risk of side effects. Can be paired with aspirin but still increases bleeding.

Question 32

What are the GPIIb/IIIa receptor antagonists? | What is their mechanism?

Answer 32

Abciximab and Eptifibatide Reversibly inhibit the final common pathway of platelet aggregation (GPIIb/IIIa receptor binding to fibrinogen and vWF) Prevents formation of hemostatic plug

Question 33

``` Differences between Abciximab and Eptifibatide: Source Binding Kinetics Indication Co-administeration ```

Answer 33

Abciximab: S - Chimeric human-mouse monoclonal Ab B - Blocks Fibrinogen, vWF access to GP IIb/IIIa receptor K - Non-competitive, IV I - PCI: Angioplasty and stent C - Aspirin and heparins; also with alteplase for thrombolysis Eptifibatide S - Synthetic peptide antagonist B - Sequence motif specifically binds to GP IIb/IIIa receptor K - Competitive. IV, Renal I - PCI: Angioplasty and stent; Unstable angina and MI C - LMWH often for unstable angina and MI

Question 34

What is dipyridamole? When is it given? What is known about its action? What is its efficacy?

Answer 34

Anti-platelet Given to patients who cannot tolerate aspirin Unclear: Increases platelet cAMP so blocks phosphodiesterase, blocks platelet uptake and destruction of adenosine If given alone the drug has no proven cardiac benefits

Question 35

What are some new oral anti-coagulants? | What are some potential indications for them?

Answer 35

Dabigatran and Rivaroxaban Reduce risk of stroke, systemic embolism in patients with nonvalvular atrial fibrillation; Reduce the risk of recurrent ischemia after an ACS event

Question 36

What are the aspirin recommendations for primary prevention?

Answer 36

Low dose (75 to 325 mg.day) to patients with clinical manifestation of CAD, assuming no contraindications in patient Should not be prescribed routinely for primary prevention purposes to completely healthy individual Possibly recommend to patients over 50 yo and have at least one major risk factor