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Block 3b1 PHM > DVT/PE > Flashcards

Flashcards in DVT/PE Deck (51):
1

Prophylaxis & acute mgt of DVT (2)

UFH/LMWH

2

Category & ex's (2) of drugs for long-term DVT prevention

Oral anticoagulants: Warfarin & Rivaroxaban

3

Virchow's Triad

"SHE"
Stasis: post-op/long drive or flight

Hyper coagulability: coagulation cascade problem
(ie: Factor V Leiden mutation)

Endothelial damage (i.e.: exposed collagen that triggers clotting cascade)

4

Imaging test of choice for DVT

Compression ultrasound w/ Doppler

5

Imaging test of choice for PE

CT pulmonary angiography

6

Factor Xa Anticoagulant w/ greatest efficacy & 2 examples

LMWH (dalteparin, enoxaparin)

7

Direct Xa Inhibitors (2)

Apixaban, Rivaroxaban

8

Factor IIa (Thrombin) Anticoagulant w/ greatest efficacy

Heparin

9

Direct Thrombin Inhibitors (3)

Argatroban, Dabigatran, Bivalirudin,

10

Prophylaxis and Acute Mgmt of DVT

UFH or LMWH (eg: enoxaparin)

11

Tx & Long term prevention of DVT

Oral anticoagulants (eg: warfarin, rivaroxaban)

12

Indirectly lowers activity of thrombin and factor Xa w/ short T1/2

UFH

13

Clinical Use of Heparin

Immediate anticoagulation for pulmonary embolism
acute coronary syndrome, MI, DVT

14

Anticoagulant that doesn't cross placenta & monitored via PTT

Heparin

15

AE of Heparin

Bleeding, Thrombocytopenia (HIT), osteoporosis, hypoaldosteronism, hyperkalemia, drug-drug interactions

16

Rapid reversal agt vs. Heparin

Protamine Sulfate: (+) charged molecule that binds (-) charged Heparin

17

Heparin class that acts predominantly on Factor Xa (#1-w/ 2ex's) and only on Factor Xa(#2)

1) LMWH (eg: enoxaparin, dalteparin)
2) Fondaparinux

18

MOA of Heparin-induced Thrombocytopenia (HIT)

dev of IgG ab's vs. heparin bound PT factor 4 (PF4)
ab-Hep-PF4 complex activates PT's->Thrombosis & Thrombocytopenia

19

Only PO direct thrombin inhibitor

Dabigatran

20

Clinical use of direct thrombin inhibitor

VTE, a fib, HIT
*doesn't require lab monitoring*

21

What can reverse dabigatran (direct thrombin inhibitor)?

idarucizumab

22

MOA of Warfarin
What is its metabolism affected by?

interferes w/ Y-carboxylation of vit K dep clotting factors (II, VII, IX, X) and proteins C & S

metabolism influenced by polymorphisms in gene for vit k epoxide reductase complex (VKORC1)

23

What is the effect of warfarin in a laboratory assay?

effect on extrinsic pathway, ↑ PT and w/ long T1/2

24

Clinical Uses of Warfarin (2)

Chronic anticoagulation (eg: VTE prophylaxis) & stroke prevention in a fib

25

CI of Warfarin

Pregnant women bc crosses placenta; follow PT/INR

26

AE of Warfarin

Bleeding, teratogenic,
skin/tissue necrosis*
(due to small vessel micro thrombosis*)

27

Explain the early transient hyper coagulability w/ warfarin use

Factors C & S with shorter T1/2 than clotting factors II, VII, IX, X

28

Warfarin reversal (a) & rapid reversal (b)

Vit K (a)/FFP or PCC (b)

29

What is heparin "bridging" & why is it imp?

Heparin frequently used when starting warfarin
Heparin's activation of antithrombin enables anticoagulation during initial transient hyper coagulable state caused by warfarin

Initial heparin Tx ↓ risk of recurrent VTE & skin/tissue necrosis

30

Compare route of admin, site of action & onset of action in Heparin vs. Warfarin

Heparin:
Parenteral (IV, SC)
Blood
Rapid (secs)

Warfarin:
PO
Liver
Slow, limited by half lives of normal clotting factors

31

Direct Factor Xa Inhibitors (2)

Apixaban, Rivaroxaban

32

Clinical use of direct Factor Xa inhibitors (2)

Tx and prophylaxis of DVT & PE , stroke paralysis in patients w/ a fib

33

+ of oral anticoagulant agents?

Don't usually require monitoring

34

AE & limitation of direct factor Xa inhibitors

Bleeding; not easily reversible

35

Grade the reversibility of the heparin classes

UFH: Robust
LMWH: Moderate
FPX: Little, if any

36

What are HIT paradoxes?

Anticoagulant-induced thrombosis
Clotting, not bleeding disorder
PT transfusions can ↑ thrombosis risk
Simply stopping heparin may not prevent thrombosis
Warfarin CI as acute monotherapy

37

How might HIT present clinically?

Drop in PT count & or new thrombosis

38

Describe the nature of heparin exposure in HIT in terms of

a) Heparin Class
b) Dose/Duration
c) Route of admin
d) Clinical Setting

a) UFH>LMWH
b) High>Low dose
c) Long term>Short term
IV>SC, flushes, heparin coated devices
d) cardiac, orthopedic or ICU

39

Derivation & action of Argatroban

L arginine; Univalent inhibitor of thrombin, inhibiting clot bound & soluble thrombin

40

Indication of Argatroban

Anticoagulant for prophylaxis/Tx of thrombosis, or PCI in patients w/ HIT*

41

Anticoagulant w/o cross-reactivity w/ heparin induced antibodies

Argatroban

42

Limitation of Argatroban

No known antidote

43

Therapeutic Effect of Argatroban

Rapid, ~30 mins (IV but no bolus)

44

Argatroban Elimination

Hepatic metabolism; T1/2 ↑ in patients w/ mild hepatic impairment

45

Given the challenging transition from Argatroban, what other drug may be beneficial?

Direct Factor Xa Inhibitors

46

What are 2 imp points to remember during Argatroban therapy transition?

1) Don't rely on warfarin alone until HIT is adequately controlled
2) Give several days for warfarin to attain its therapeutic effect

47

What are some criteria that have to be met before Argatroban is discontinued? (5)

-INR>4.0^2
-Obtain INR 4-6 hours after Argatroban discontinued
-Absence of new TEC's
-PT recovery
-Restart Argatroban Tx if INR falls below therapeutic range

48

What are 2 anticoagulants that are CI in acute HIT?

a) Warfarin
b) LMWH: cross-reactive w/ heparin antibodies

49

What is one + of Fondaparinux?

Rarely cross reacts w/ heparin ab's
No EBM but anecdotal support

50

3 +/- of Oral Xa Inhibitors

+:
PO
Easy dosing
No routine monitoring

-:
$
No antidote
Renal clearance

51

Why is warfarin not used in acute thrombotic settings?

Bc it requires 3-4 days to have anticoagulant effects