Acute VTE therapy

Question 1

General approach to acute VTE therapy

Answer 1

1) diagnosis of VTE: objective tests
2) how stable is the pt
3) do they need IVC filter
4) in vs out pt
5) selection of therapy
6) do they need stockings?

Question 2

When would someone need to get an immediate removal of clot

Answer 2

PE: with RF for poor prognosis (hypotension, brady (low HR), shock —— could go into organ failure)

DVT with limb gangrene —- possible amputation

Question 3

Methods of clot removal

Answer 3

1) pharmacological : thrombolysis (dissolve clot)
2) pulmonary embolectomy: indicated if CI to thrombolysis (active bleeding) OR failed thrombolysis therapy

Question 4

What is an IVC filter

Answer 4

Filter that goes into IVC and blocks and parts of DVT that may fall off
- stops them from reaching lungs

Question 5

When is an IVC filter indicated

Answer 5

1) pt with absolute CI to anticoagulation+ have DVT (ex// major active bleed, major bleeding disorder, platelets < 30 x 10^9)

2) pt survived major PE but wouldn’t survive 2nd

3) Pt has recurrent VTEs despite anticoag therapy

Question 6

When would a pt with a VTE automatically be admitted to hospital ?

Answer 6

hypotension, hypoxemia or tachycardia (increased HR)
—- aka if unstable

Question 7

What risk tool do we use to determine whether to treat VTE in or out pt

Answer 7

PESI score
- looks at age, sex, cancer, HR, T, RR, O2 levels

—-low risk < 66— can treat outpt
—— if older than 66— automatically high risk (treat in hospital)

Question 8

What is defined as a rapid anticoagulant

Answer 8

something that becomes effective with 1 hour
— normally SC or IV (PO—- riva or apix)

Question 9

How many days of overlap bw rapid and warfarin do we need to get adequate protection?

Answer 9

at least 5 days + 2 consecutive INR 24 hours apart that are > 2
- if using warfarin for long term therapy—- need to start when start Rapid+ have a 5 day overlap

Question 10

What is a good duration for rapid therapy

Answer 10

5-7 days as long as being followed up with LT anticoag after for at least 3mths

Question 11

What is the approximate bleed risk on UFH

Answer 11

2-5 %: increases if recent surgery, trauma, F, old, malignancy

Question 12

T or F: About 30% of pt on UFH will experience thrombocytopenia

Answer 12

T: can be directly or indirectly caused

directly: heparin binds to platelets + causes clumps (common + little worry)

indirectly: immune mediated HIT (PF4 + heparin; body makes AB —- cause platelet aggregation + activation —- pro thrombosis state)

Question 13

What are the main SEs of UFH

Answer 13

bleeding
HIT
osteoporosis: not common
—- heparin binds to blasts— activate clasts
—- only seen with LT > 6mths of use

Question 14

How common is HIT with UFH use

Answer 14

< 5%

Question 15

What to monitor when looking for HIT

Answer 15

sudden drop in platelets in first 5 days of UFH use
—- is happens: stop heparin + start fonda

Question 16

Advantages of UFH

Answer 16

IV admin: if bleed, can suddenly stop

antidote: protamine sulphate (1mg/100 units of heparin; max 50mg)

Question 17

How is IV UFH dosed

Answer 17

weight based initial dose + infusion rate

• initial bolus of 80-100units/kg + infusion rate of 17-20 units/kg/hour

—- check apTT in 4-6 hours to adjust dose if needed (if high——- lower dose)

Question 18

Negatives of UFH

Answer 18

required monitoring — apTT
— need to be in pt (IV )
— requires blood draws

no SC dosing in Canada

Question 19

What needs to be monitored with UFH

Answer 19

CBC + platelets at baseline + at 2 weeks

apTT at baseline + every so often based on protocol

Question 20

What meds are LMWHs

Answer 20

dalt, tinza, enox

Question 21

T or F: LMWH is better than UFH

Answer 21

F- there was a study that showed decreased risk of bleeds/mortality but HAD a lot of bias

—- therefore both considered equally effective

Question 22

Dalt dosing

Answer 22

200 units/kg SC daily
if > 100kg: 100 units/kg SC BID

Question 23

Tinzaparin dosing

Answer 23

175units/kg SC daily

Question 24

Enoxaparin BID dosing

Answer 24

1.0mg/kg SC BID

Question 25

T or F: we should use the 1.5mg/kg SC QD enoxaparin dosing over the BID dosing for VTE

Answer 25

F- not been studies in acute VTE treatment in comparison to UFH

Question 26

T or F: protamine sulphate can be used as an antidote for LMWH

Answer 26

T- but not as effective; 60% reversal because LMWH are SC not IV

Question 27

T or F: the rate of major bleeds with LMWH is lower than with UFH

Answer 27

F- equal

Question 28

T or F: the rates of thrombocytopenia are lower with LMWH than UFH

Answer 28

T — lower rates —can’t use if history of HIT though

Question 29

T or F: LMWH is safe in pregnancy

Answer 29

T- preferred agent; can use UFH though too

Question 30

At what creatinine clearance is LMWH CI

Answer 30

< 30

Question 31

Why do LMWH have less risk of thrombocytopenia + osteo compared to UFH

Answer 31

shorter chain —- less nonspecific binding to shit

Question 32

What is the biggest advantage of LMWH to UFH

Answer 32

convenience —- less monitoring , SC once daily; don’t need to be in hospital

Question 33

What assay can we use to monitor LMWH therapy

Answer 33

Anti-factor Xa—- don’t do it often though — not great evidence for values + how to adjust based on values

Question 34

What do we have to check at baseline when starting LMWH

Answer 34

CBC, platelets, PT/INR, aPPT and Scr

Question 35

What has to be monitored every 5-10 days during first 2 weeks of LMWH therapy

Answer 35

CBCs

Question 36

When is the only real time we use fondaparinux

Answer 36

If history of HIT — similar efficacy to LMWH (only 2 studies) — similar risk of bleeds - no antidote - renal impairment — don’t use

Question 37

Fonda dosing

Answer 37

7.5mg once daily if > 100: 10mg < 50: 2.5mg

Question 38

Efficacy of Riva vs W

Answer 38

study showed equal efficacy (in prevention of recurrent VTE) —- Time in therapeutic target for W was longer than normal though (60 vs 70%) —- Riva showed decreased bleeding risk (but open label) sooooooo bias ?? study also had multiple checkin + FU points—- not normal for riva but have with W (INR) —- may have less adherence with riva in really life

Question 39

T or F: cost of Riva + W are about the same

Answer 39

Riva; ODB covers 6 mths with LU 444 —— after you have to pay —— if have no insurance or even do: still costs more than W

Question 40

T or F: Edoxaban + Dabigatran are equally effective in preventing VTE as Riva (we have plenty of evidence on both)

Answer 40

F- —- little evidence for E + D ++++ in the studies they showed benefit of them WHEN OVERLAPPED with LMWH

Question 41

INR target for W

Answer 41

2.5 (2-3)

Question 42

T or F: elastic compression stockings can be used to prevent PTS

Answer 42

F- no evidence that starting them earlier helps prevent PTS; may helps with symptoms of PTS

Question 43

Impact of alcohol on INR

Answer 43

elevates INR — alcohol inhibits warfarin metabolism —- increasing concentration —- increase efficacy

Question 44

Impact of smoking on W

Answer 44

Increases Cl—- induces metabolism —- INR decrease + may need a higher dose of W