Week 5 - VTE Flashcards
(28 cards)
When should you suspect DVT?
Any of the following criteria (2+ ==> high chance)
- Unilateral leg swelling
- Tibial swelling >3cm
- Entire leg swollen
- Cancer
- Hx of DVT
- Recent cast/immobilization/surgery
- Superficial veins
- Localized pain over venous area
- No other likely Dx
How do you test for DVT if there is a low/moderate suspicion of DVT?
D-dimer
High sensitivity ==> Neg rules out DVT
==> Pos only suggests need for more testing
What are the imaging tests for DVT and when are they done?
Doppler US
- accurate at assessing proximal veins
- if Neg & low clinical suspicion ==> no DVT
- if Neg & high clinical suspicion ==> retest next week
- If Pos ==> DVT dx confirmed
Used in patients who have:
- low/mod clinical probability & Pos D-dimer
- high clinical probability
What is the presentation of PE?
Either SOB &/or Chest pain may be noticed
SOB
- new onset
- may only notice after exercising
Chest pain
- pleuritic
- pain on inspiration
may also have hemoptysis
When should you suspect PE?
Any of the following criteria and no other dx
- Symptoms of DVT
- HR > 100
- Recent surgery/immobilization
- Hx of DVT/PE
- Hemoptysis
- Malignancy
What are the imaging tests for PE and when are they done?
CT (gives more conclusive results) & V/Q scans
Used in patients who have:
- low/mod clinical probability & Pos D-dimer
- high clinical probability
What are some risk factors for VTE?
Surgery
- ex. hip & knee replacements
- immobility (casts, paralysis)
Hormonal Tx
- pregnancy & 6 wks post-partum
- HRT
- OCP (oral contraceptive pills)
Cancer (active CA or currently in Chemo Tx)
Air travel
- due to immobility
- due to changes in air pressure
What are some hereditary risks of Thrombosis?
Factor V Leiden** (most common)
Prothrombin
More rare but more severe = Deficiency of:
- Protein C
- Protein S
- Antithrombin
ONLY A/W VENOUS THROMBOSIS
List some non-hereditary risks of Thrombosis.
Anti-phospholipid syndrome
- Lupus anti-coagulant
- Anticardiolipin Ab
- B2 Glycoprotein 1 Ab
- *Must all stay persistently positive over 3 mo.
These people are at higher risk of recurrent thrombosis
A/W BOTH VENOUS & ARTERIAL THROMBOSIS
When would testing be ordered?
Not very often because it does not change tx/management and does not change outcome/risk of recurrence.
Only test if we think it would change tx/mgmt for a family.
Why do we treat pts with DVT/PE?
Reduce risk of:
- death
- post-thrombotic syndrome (clotting/swelling in leg)
- pulm HTN due to thromboembolic disease
What is post-thrombotic syndrome?
What is the tx/prevention?
- Chronic venous insufficiency
- Chronic limb aching
- Skin ulceration
Tx/Prevention:
Compression socks
What is the Tx for DVT/PE
- *ANTI-COAGULATION**
- block new clot formation
- -> inhibit production of fibrin
- don’t break down clot
Sometimes use:
- Thrombolytics (Heparin- anti-inflammatory –> help relieve pain)
- Surgical Thrombectomy
- IVC filter
What types of anti-coagulants would be used to treat PE/DVT?
Start both tx immediately:
Immediate-acting:
- Heparin (UFH or LMWH)
Delayed-acting:
- Warfarin/Vit K antagonists
How long does Heparin need to be taken?
> 5 days, INR > 2 for 2 days
How long should Warfarin be taken
> = 3 months
What is Rivaroxaban?
Factor Xa inhibitor Immediate-acting Metabolized similarly between people Don't need to monitor INR ~$3/d
When would IV UFH be used?
Hopitalized/critically ill pts
Post-op, ICU
Risk of bleeding
Renal disease
*UFH has a short half-life and can be reversed with other agents
Explain the pharmacokinetics of LMWH.
SubQ Longer half-life than UFH Does not require monitoring Much harder to reverse Renally excreted ==> can accumulate in pt w renal failure
Adverse effects of Heparin
Increased risk of bleeding &
Heparin-induced-thrombocytopenia (HIT)
What is Heparin-induced-thrombocytopenia (HIT)
Drug-induced, immune mediated syndrome
- Pt makes Ab against Heparin/PF-4 complex
- can lead to thrombocytopenia or thrombosis
- 5-7d after starting Heparin
- Pts should receive CBC 5-7d after starting to monitor for this
How would thrombocytopenia be diagnosed?
4 T Score:
- Degree of Thrombocytopenia
- Timing
- Thrombosis
- Alternative Cause
Can see lots of microthrombi in hand (dark extremities)
Determines low vs high risk
Low–> unlikely HIT
High–> do HIT assay and switch to new anticoagulant
How would you treat HIT?
NOT WITH HEPARIN, EVER!
Alternate anti-coagulants:
- Fondaparinux
- Argatroban
- Danaparoid
- Lepirudin
Tx of VTE?
Start Tx with anti-coagulation
Follow next day with dx US
If Pos, continue anti-coag tx
