4. VTE Flashcards
(22 cards)
Risk factor for DVT/PE (virchow’s triad) → increase risk of clotting
- Hypercoagulability (major surgery, malignancy, pregnancy, thrombophilia, infection, IBD, protein C or S deficiency, factor V Leiden)
- Vascular damage (cellulitis, physical trauma, indwelling catheter/ heart valve)
- Circulatory stasis (immobility, venous obstruction - obesity, pregnancy, AF)
Location of DVT
- Legs (above knee): likely to embolise → right heart → PE → occlude blood flow to lungs
- Calf: unlikely to embolise
Clinical presentation of DVT (S/S)
- Symptoms: leg swelling, pain, warmth, usually unilateral
- Signs: superficial veins that are palpable (bulging veins), Homan’s sign (pain in back of knee when feet is moved upwards)
Diagnosis of DVT - Wells-DVT Score (for DVT)
- 0-2 points: unlikely/ moderate likelihood of DVT → D-dimer test
- > 2 points: likely DVT → carry out proximal compression ultrasound (CUS)
Treatment of VTE (DVT)
anticoagulants (no antiplatelets)
thrombolytics not needed
UFH (VTET & VTEP doses)
VTET: IV 80 u/kg followed by 18 u/kg/hr
VTEP: ?
LMWH (eg enoxaparin) (VTET & VTEP doses)
renally impaired dose?
VTET: SC 1mg/kg BD
Renal: CrCl <30ml/min: 1mg/kg OD
VTEP: SC 40mg OD/ SC 30mg BD
Dabigatran (VTET & VTEP doses)
renally impaired dose?
VTET: parenteral anticoagulant x5d → 150mg BD
Renal: CrCl <50ml/min + PGP inhibitor: avoid
VTEP: ??
Rivaroxaban (VTET & VTEP dose)
renally impaired dose?
VTET: 15mg BD x21d → 20mg OD (up to 6mths) → 10mg OD
CrCl <30ml/min: avoid
VTEP: 10mg OD
Apixaban (VTET & VTEP dose)
renally impaired dose?
VTET: 10mg BD x7d → 5mg BD (up to 6mths) → 2.5mg BD
CrCl 15 to <30ml/min: use with caution
VTEP: 2.5mg BD
Edoxaban (VTET & VTEP doses)
renally impaired dose?
VTET: parenteral anticoagulant x5d → 60mg OD
CrCl 30 - 50ml/min OR BW ≤60kg: 30mg OD
VTEP: 30mg OD
warfarin for VTET/P
parenteral anticoagulant overlap for ≥5d AND INR ≥2.0
PO Warfarin (INR target 2.5/ 2.0 - 3.0)
Duration of tx for VTE
- Transient/reversible RF: sepsis, road traffic accident → stop at 3mths
- Chronic/continuous RF: obesity, prolonged immobility → continue tx (reassess at 6mth)
- @6mth continue anticoagulant if still have chronic RF (antiphospholipid syndrome. prolong immobility)
when to use/not use fibrinolytics (rTPA, tenecteplase)
any RF of bleeding is an exclusion criteria for use of thrombolytics (increase risk of bleeding)
PE diagnosis
≤4 points: unlikely PE
>4 points: likely PE → imaging
S/S of PE (differential dx: MI)
- Symptoms: cough, chest pain, chest tightness, SOB, palpitation, hemoptysis (cough up blood), dizziness, light headedness
- Signs: tachypnea, tachycardia, diaphoretic (sweating profusely), cyanotic (blue), hypotensive, hypoxic (low O2)
Criteria for high risk PE
- Cardiac arrest
- Obstructive shock - SBP <90mmHg, end organ hypoperfusion (cold, clammy skin, oliguria/anuria, incr serum lactate)
- Persistent hypotension - SBP <90mmHg or drop ≥40mmHg
- RV dysfunction on imaging (TTE, CTPA)
- Elevated cardiac troponin levels (heart muscle die)
Tx for high risk PE (+ rationale)
IV bolus UFH + thrombolytics (rTPA)
- UFH is easily reversible in case pt bleeds with thrombolytics use
- Thrombolytics: high risk of mortality > risk of bleeding
Tx for intermediate-low risk PE
(parenteral) SC LMWH/ fondaparinux (instead of UFH) - to ensure sufficient AC at clotting site
(oral) DOAC (preferred over VKA)
- parenteral anticoagulant overlap for ≥5d AND INR ≥2.0 [PO Warfarin INR target 2.5/ 2.0 - 3.0]
Duration of tx for PE
same as DVT
Severe renal impairment (CrCL <30mL/min) VTET
- DOAC not recommended
- Recommended: Warfarin + UFH
- Alternative: warfarin + dose-reduced enoxaparin
Pregnancy VTET
Recommended: LMWH (SC enoxaparin 1.0mg/kg BD) → VTEP SC 40mg OD or 30mg BD
- Warfarin teratogenic in 1st trimester
- DOAC can be used but not well studied
