VTE & PE Flashcards
risk factor for VTE & PE
Virchow triad
1) hypercoagulability (blood)
2) vascular damage (vessel)
3) stasis (flow)
pathophysiology of VTE & PE
thrombi originate from leg
- calf (distal) unlikely to embolise
- above knee (proximal) likely to embolise
** primary clot break off into small clot -> embolus travel to right heart -> travel to pulmonary artery -> lodged in lungs -> embolus occlude blood flow in lung -> pulmonary embolism
pulmonary embolism -> impaired gaseous exchange -> necrosis of lung tissue -> impaired O2 delivery to other organs -> fatal circulatory collapse
clinical presentation of DVT/VTE
1) Symptoms
- leg swelling, pain, warmth
- unilateral
2) signs
- superficial veins dilated (visible), palpable cords felt in affected leg
- Homan’s sign: pain in back of knee when examiner dorsiflex foot of affected legs
clinical presentation of PE
1) symptoms
- cough, chest pain, chest tightness, SOB, palpitations
- maybe cough/spit out blood (hematoma)
- severe: dizziness, lightheaded
2) signs
- tachypnoea, tachycardia, diaphoretic (sweat a lot)
- distended neck veins
- severe: cyanosis, hypotensive, hypoxic
- maybe cardiogenic shock -> die within mins
diagnosing VTE
1) rule out cellulitis, fluid overload
2) Well’s score
- probabilities of DVT
** high probability ≥ 3
** moderate probability 1- 2 - actions after getting score
** if score ≥ 2 then conduct compression ultrasound (CUS)
1. if proximal DVT -> initiate anticoagulation
2. if distal DVT -> monitor, can recommend anticoagulation
** if score ≤ 1 then D-dimer test
1. +ve -> US
2. -ve -> rule out DVT
diagnosing PE
Well’s criteria
- > 4: imaging
- ≤ 4: D-dimer
what are some baseline tests before pharmacotherapy for VTE/PE
1) FBC
2) renal panel to determine which drug
3) procalcitonin to check for infection
general treatment plan for VTE
acute phase and early maintenance of DOAC for 3 months then repeat CUS
- if transient/provoked and reversible risk factors or high risk of bleeding then stop after 3 months
- if thrombus, unprovoked, irreversible risk factor then continue lower dose prophylactic dose past 6 months
apixaban for VTE
- most commonly used
- dosages
** initiation: 10mg BD for 7 days
** maintenance: 5mg BD for 83 days
** after 6 months: 2.5mg BD - CI: severe renal/liver impairment (CrCl < 30 or HD), pregnancy, lactation, APS, heart valve replacement, azoles
rivaroxaban for VTE
- dosages
1) initiation: 15mg BD for 21 days
2) maintenance: 20mg OD for 69 days
3) after 6 months: 10mg OD - CI
1) severe liver/renal impairment (CrCl < 50 or HD)
2) pregnancy, lactation
3) APS, heart valve replacement, azoles
which DOAC are more common for private practice for VTE?
dabigatran, edoxaban
dabigatran for VTE
- dosages
1) initiation: enoxaparin 1mg/kg BD for 5 days
2) maintenance: dabigatran 150mg PO BD for 85 days - CI
1) severe liver/renal impairment (CrCl < 50)
2) pregnant, lactation
3) APS, heart valve replacement, azoles
edoxaban for VTE
- dosages
1) initiation: enoxaparin 1mg/kg BD for 5 days
2) maintenance: edoxaban 60mg OD for 85 days - contraindication
1) not recommended if good renal clearance
2) severe liver/renal impairment
3) pregnancy, lactation
4) APS, heart valve replacement, azoles
what to use for VTE when there is severe renal impairment or APS?
warfarin
- warfarin PO + enoxaparin 1.0mg/kg every 12 hrs for 5 days until target INR ≥ 2
** once target INR reach then remove enoxaparin and dose adjust warfarin based on INR 2.5
** dose adjust warfarin based on INR 3 if heart valve replacement
** reduce dose by 25% if on bactrim/ciprofloxacin
** CI in pregnancy, lactation
special populations for VTE treatment
1) pregnancy
- higher risk for VTE esp during post-partum period
- things to take note of: history, obesity, pre-eclampsia, still birth, post-partum haemorrhage
- drug choice: enoxaparin > dabigatran/edoxaban
** SQ 1mg/kg every 12 hrs
** if CrCl < 30 then 1mg/kg every 24 hrs - D-dimer can increase w pregnancy so need to check properly
