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Flashcards in 1 - Bleeding Deck (48):
1

What is the second most numerous cell in the bloodstream, and how often is it replaced by the body?

Platelets - every 10 days

2

Where are clotting factors synthesized?

In the liver

3

What is necessary for the synthesis of 4 clotting factors? What are they?

Vitamin K

Factors II, VII, IX, X

Protein C and S

4

What is heparin primarily secreted by?

  • Mast cells & basophils

5

Where do clots on the left and right side lodge?

  • Left side of body
    • Blocks arterioles - ischemia to organs
  • Right side of body
    • Pulmonary arteries to lungs - pulmonary embolism (PE)

6

Why is bacterial endocarditis treated with both antibiotics and anticoagulants?

Because circulating bacteria and their endotoxins activate clotting = septic shock

7

What are the clotting cascade steps?

  • Prothrombin
  • Thrombin
  • Fibrinogen
  • Fibrin

8

What is the leading cause of re-hospitalization following joint replacement surgery?

Deep vein thrombosis and Pulmonary embolism

9

What are anti-platelet drugs used for?

  • To reduce the risk of stroke and other adverse thromboembolic events

10

What is a percutaneous coronary intervention (PCI)?

Stent - bare-metal and drug-eluting stents

Optimal treatment for many patients experiencing acute coronary syndromes

11

Aspirin along with antiplatelets do what to platelets?

Cause irreversible effects

12

What is the most comprehensively studied and least expensive of all antiplatelet medications?

Aspirin - acetylsalicyclic acid (ASA)

13

In dentistry - what is the drug for MI treatment for patients having a heart attack for pre-hospital admission?

Aspirin - 325 mg full strength, 81 mg low dose

14

If there is a well-documented and justifiable need to discontinue aspirin before dental treatment, wait at least ______ prior to invasive surgical procedures.

1 week -  it allows for platelet turnover

15

What does discontinuing the use of aspirin suddenly do?

Increases mortality risk - 3 fold higher risk 

Even higher in pts with coronary stents - by a factor of 89

16

What older antiplatelet drug can be used with warfarin to decrease thrombosis following placement of artificial heart valves?

dipyridamole (Persantine)

17

What antiplatelet drugs fall under the category of Theinopyridines?

  • ticlopidine (Ticlid)
  • clopidogrel (Plavix)
  • prasugrel (Effient) - new drug in 2009

18

What drug is used for those who are intolerant to aspirin, and coronary stent implantation has taken place?

ticlopidine (Ticlid)

- lowers risk of stent thrombosis

19

What drug prevents the binding of ADP to collagen receptors which prevents platelet aggregation?

clopidogrel (Plavix)

- Replaced use of ticlopidine, better safety-tolerance profile

20

What are the indications for clopidogrel (Plavix)?

  • Reduce rate of TE (MI, stroke, vascular death) in pts with recent MI or stroke
  • Reduce rate of TE in pts with unstable angina managed medically or with PCI

21

What is the main course of action of theinopyridines?

Inhibit the ability of adenosine diphosphate (ADP_ to induce platelet aggregation -- irreversible effect

22

What is the US boxed warning on prasugrel (Effient)?

May cause significant or fatal bleeding - contraindicated in pts with active pathological bleeding or history of TIA or stroke.

23

What are the 3 recommendations from advisory statement concerning disconinuation of anti-platelets?

  1. Consult cardiologist to discuss optimal pt management strategies
  2. Elective procedures with risk of bleeding should be deferred until pt has completed appropriate course of thienopyridine therapy
    1. 12 months after DES implant (stent)
    2. Minimun 1 month for bare-metal stent
  3. Pts with DES who have procedures, aspirin should be continued - restart thienopyridine asap

24

What are platelet glycoprotein IIb/IIIa receptor antagonists (fibrinogen receptor inhibitors) used for?

Used with aspirin and heparin to treat acute coronary syndromes via IV infusion

25

What are the platelet glycoprotein IIb/IIIa receptor antagonists (fibrinogen receptor inhibitors)?

  • abciximab (ReoPro)
  • eptifibatide (Integrilin)
  • tirofiban (Aggrastat) - most widely prescribed

26

In the pathway for platelet adhesion, where do platelet glycoprotein IIb/IIIa receptor antagonists (fibrinogen receptor inhibitors) act?

Final common pathway - inhibits binding of fibrinogen, von Willebrand factor and other adhesives to form platelet aggregation

27

What kind of effect do NSAIDS have on platelets?

Reversible

28

What is the US boxed warning on NSAIDS?

They are associated with an increased risk of adverse cardiovascular thrombotic events, including fatal MI or stroke

29

From FDA advisory statement - "ibuprofen can interfere with the anti-platelet effect of low dose _______ (___ mg per day), potentially rendering _______ less effective when used for cardioprotection and stroke prevention."

  1. aspirin
  2. 81 
  3. aspirin

30

What should pts do if they had to take ibuprofen with aspirin?

Ibuprofen at least 30 minutes or longer after aspirin ingestion, or more than 8 hours before aspirin ingestion.

31

What are the antithrombins along with their indications?

  • Antithrombin III - antithrombin III deficiency
  • Heparin - enhances inhibition rate of clotting proteases by antithrombin III
  • Low molecular weight heparins - prevention/treatment of thromboembolic disorders

32

How does heparin work?

Inactivation or thrombin - final common pathway

33

What is the antidote to heparin?

Protamine

34

What are the common low molecular weight heparins and what is it's use?

Used to prevent DVT with or withour PE, acute unstable angine

  • dalteparin (Fragmin)
  • enoxaparin (Lovenox)
  • tinzaparin (Innohep)

35

What is an oral anticoagulant that interferes with liver synthesis of vitamin-K dependent clotting factors?

warfarin (Coumadin, Jantoven)

36

What are some important indications for taking warfarin (Coumadin)?

  • Atrial fibrillation
  • Cardiac valve replacement
  • Adjunct to reduce risk of systemic embolism after MI
    • Takes about 4-5 days for effects

37

Drugs that induce liver metabolism will do what to the level of warfarin?

Decrease it - it's metabolized by P450 enzymes

38

What can upsest a pts level of anticoagulation from warfarin?

  • Leafy greens - vitamin K intake
  • Fever
  • Flu
  • Diarrhea or vomiting

39

What are some dental implications with warfarin?

  • Increased gingival bleeding and mouth ulcers
  • No need to discontinue warfarin prior to routine dental procedures

40

What is activated partial prothrombin time (aPTT) used to measure?

The effects of heparin, which increases aPTT to 50-70 seconds

41

What is used to measure the effect of warfarin?

International normalized ratio (INR)

42

What is the therapeutic INR range for pts with venous thrombosis, embolisms and atrial fibrillation? And the therapeutic INR range for mechanical prosthetic heart valves?

  1. INR = 2.0 - 3.0
  2. INR = 2.5 - 3.5 for prosthetic heart valves

43

What is the significant dental drug interaction with warfarin?

acetaminophen (Tylenol) - enhances anticoagulation 10 fold 

44

What causes the greatest number of drug interactions?

warfarin (Coumadin, Jantoven) 

**Always ask about the INR and monitor INR status across time ***

45

What is dabigatran (Pradaxa)?

Thrombin inhibitor - FDA approved Oct 2010

  • Prevents stroke and systemic embolism in pts with atrial fibrillation

46

What are the advantages and disadvantages of dabigatran compared to warfarin?

  • Advantages
    • No monthly monitoring, less interactions
  • Disadvantages
    • Expensive, twice daily dosing, bleeding, GI effects

47

What is the first and only oral anticoagulant approved in US for orthopedic surgery?

rivaroxaban (Xarelto) - prevents DVT following hip replacement

48

What are the main Clot-Busting drugs and when are they used?

Used within hours of adverse embolic event 

  • tPA (tissue plasminogen activator) - IV drug
  • streptokinase (Streptase)
  • urokinase