VTE + anticoagulation Flashcards
What is a distal DVT
Popliteal vein - behind knee or below
What is a proximal DVT
Above the popliteal
Sites of a PE
Central #Segmental
Sub segmental
COmplications of PE
Post thrombotic syndrome
Pulmonary HPTN -> cor pulmonale
Psychological - stress, anxiety et c
Risk factors PE
Cancer
Pregnancy + 6 weeks PP
Surgery - over 30 mins
Fracture, esp if immobile/cast
Flight >4 hours
Recent hospitalisation
Hormone therapy - COCP, HRT
Immobility>3 dyas
How to rule out DVT
Low wWells score + negative D dimer
What is the problem with D dimer
High prevalence groups may have negative D dimer and PE
When is active phase
4 weeks after initial
Treatment prevents -> PE or extension of clot
Contraindication for DOACs
Impaired renal function, extreme weights, elderly
What are LMWH particuarly good for
Stopping and starting - immediate effet
eg tinzaparin
What drug do you use for a goal INR of 3-4
Warfarin
What anticoag use in severe renalimpairment
Warfarin
What drug more likely cause ICH and is reversible
Warfarin
What are clots like in heparin induced thrombocytopenia?
Platelet rich white clot (more common arterial disease)
Do you treat sub segmental PE
If symptomatic yes #If not detabatable
What is budd chiari syndrome
Thrombosis of hepatic veins which drain liver -> culminant hepatitis liver failure
What is portal vein thrombosis
Clot in portal veins, bring blood from GI tract into liver - 1/3 of hepatic nutrients/O2
What causes upper limb clots
In the upper extremity, 40-80% of clots are related to central venous catheters, and 4% are related to anatomic thoracic outlet obstruction/tight space between subclavian and 1st rib.
Massive eg illiofemoral DVT presentation
phlegmasia cerulea dolens (venous gangrene, cyanosis, arterial compromise).
What is pleuritic chest pain
i.e. sharp, localized, worse when taking a deep breath, persistent;
Why repeat US in one week for DVT
Check for signs of extension/embolisation as often within one week
Wells categories DVT
1 bedridden > 3day or major surgery past 4 weeks
1 cast/immobilization lower extremity
1 active cancer or cancer treatment past 6 months
1 swelling of entire leg
1 collateral veins
1 tenderness along deep veins
1 pitting oedema greater in symptomatic leg
1 calf swelling >3 cm diameter at 10 cm below tibial tuberosity
-2 alternative diagnosis more likely than DVT
Management dependent on Wells
-2-0 = low probability
1-2 = moderate probability
>2 = high probability
low or moderate probability: if D-dimer negative, DVT excluded; if D-dimer +, proceed to
compression U/S
high probability: Proceed to U/S. If U/S negative or inconclusive, repeat in 1 week or
consider MRV/venography.
Wells categories for PE
3.0 – signs/symptoms of DVT
3.0 – alternative diagnosis less likely (to me, practically this often means hypoxaemia
with a clear CXR)
1.5 – previous DVT/PE
1.5 – tachycardia
1.5 – immobilization/plaster cast/surgery past four weeks
1.0 – haemoptysis
1.0 – active malignancy
Managemnt depending on Wells score PE
> 4 = PE likely need CTPA or V/Q
≤ 4 = PE unlikely
- if D-dimer positive, CTPA or V/Q
- if D-dimer negative, PE excluded
Investigations lower DVT
Compression US +/-doppler
Venography gold standard but rarely done
What investigation for isolated iliac vein thrombosis in pregnancy
MR venogram
Options for treating VTE
1) DOACs: rivaroxaban, dabigatran, apixaban
2) LMWH
3) Warfarin
4) IV UFH
5) Others- fondaparinux
Minimum duration for heparin therapy
5 days AND therapeutic INR x 48 hours
Thrombolysis indications in VTE
Massive PE (with hypotension)
DVT w plegmasia cerulea dolens
Clinical evidence of RHF eg raised JP, unable to ambulate
MOA of unfractionated heparin
IIa and Xa binds, 30-60 min onoset of action, immediate if IV
Dosage TE treatment UFH in hosptial
80 U/kg IV bolus followed by a rate of 18 U/kg/hour (follow UFH levels)
What Creatinine clearance is dangerous for LMWH use?
<20/30ml/min
VTE prophylaxis with LMWH
- VTE prophylaxis
Dalteparin: 5,000 U SC OD
Enoxaparin: 40 mg SC OD or 30 mg SC BID. If >100kg, 60 mg SC OD
Tinzaparin: 35-55 kg: 3500 U SC OD, 56-100 kg: 4500 U SC OD
VTE treatment with LMWH
- VTE treatment
Dalteparin: 200 U/kg SC OD or 100 U/kg SC BID
Enoxaparin: 1.5 mg/kg SC OD or 1 mg/kg SC BID
Tinzaparin - 175 U/kg SC OD
Monitoring on LMWH
CBC and CrC
Not routinely required unless obese, renal dysfunction, unexplained bleeding, breakthrough thrombosis, regnancy
Common indications for warfarin
Stroke prevention AF
Long term secondary prevention of VTE
Prevention of thrombosis or systemic embolisation in patients with mechanical heart valves
Metabolism of warfarin
CYP450
Renal concerns with warfarin
No need to cahnge dose
CKD can increase bleeding risk
What INR goal for patients with mechanica heart vlave
INR 2.5-3.5
Complications of warfarin treatment
Warfarin skin necrosis
Purple toe syndrome
Tetraogenic in first trimester - crosses placenta
What is apixaban
Xa inhibitor
Half life and onset of apixaban
12 hour half life (longer in elderly)
Rapid onset of action 30 mins with peak effect at 3-4 hours
Metabolism of apixabam
CYP3A4 and P-gp substrate
Whaat drugs avoid with apixaban
CYP3A4 inhibitors - increase serum concentration of apixaban
CYP3A4 inducers - decrease
Dosing of apixaban
- VTE treatment: 10mg PO BID for 7 days, then 5mg PO BID (does not require initial heparin or LMWH)
- Reduction in risk of VTE recurrence: 2.5mg PO BID after at least 6 months of treatment
- VTE prophylaxis: 2.5mg PO BID, start 12-24 hours post-op if hemostasis achieved
- Atrial fibrillation: 5mg PO BID or 2.5mg PO BID if 2 out of 3 of the following – Age ≥ 80 years, weight ≤ 60kg or serum creatinine ≥ approximately 133 μmol/L
Renal adjusments with apixaban
Dose adjust in mild to mod renal impairment
Not recommended if severe eg CrCl <25ml/min
Liver CIs with apixaban
ALT/AST 2-3x upper limit
Bilirubin >1.5 x ULN
Dabigatran MOA
Direct thrombin inhibitor
Onset of dabigatran
T½ approximately 8-12 hours (prolonged in elderly); Rapid onset ofaction 30 minutes with peak effect at 2 hours;
Can you use other CYP enzyme metabolised drugs with dabigatran
Yes - not metabolised by them
