VTE Flashcards
What is the difference between DVT and PE
DVT -Blood clot in a deep vein
P.E- detachment of blood clot that travels to the lungs and blocks pulmonary artery.
Which patients are at risk of VTE
Immobile
Obese
Malignant disease
History of VTE
Over 60
HRT/contraceptive
varicose veins with phlebitis
Pregnancy
Critical care
significant co-morbidities
relative with VTE
Who are at risk of bleeding?
Patients on anticoagulants
Systolic hypertension
Thrombocytopenia (low platelet)
Acute stroke
Bleeding disorders
Acquired: liver disease
Inherited:haemophillia
What are different forms of prophylaxis against blot clots?
Mechanical prophylaxis:
compression stockings
Pharmacological VTE prophylaxis:
Parenteral anticoagulants and DOACs
What are examples of parenteral anticoagulants?
-LMWH
-Unfractionated Heparin in renal failure
-Fondaparinux
When are DOACs used for VTE prophylaxis?
Prophylaxis after knee/hip replacement surgery
Edoxaban: treatment and prevention recurrent VTE.
How long would you give VTE prophylaxis for following surgery?
General-5-7 days
Major cancer surgery in abdomen or pelvis- 28 days
Knee/hip surgery: extended duration
What is TREATMENT of VTE?and what is length of treatment?
LMWH or unfractionated heparin in renal failure
For at least 5 days and until INR at 2 or more for at least 24 hours
Monitor APTTif unfractionated Heparin given
Start oral anticoagulant at the same time(usually warfarin)
What VTE is used in pregnancy and why?
LMWH
Lower risk of osteoporosis and heparin induced thrombocytopenia (HIT)
HEPARIN:
Heparin and Fondaparinux (parenteral)
What are common indications?
Can be given in ACS to reduce clot progression
HEPARIN:
What is the mechanism of action?
It activates antithrombin which inactivates clotting factors (II and Xa) providing a natural break to the clotting process.
Heparin and fondaparinux enhance the anticoagulant effect of antithrombin
What is fondaparinux?
A synthetic pentasaccharide that mimics the sequence of the binding site of heparin to antithrombin and is very specific for factor Xa
Heparin and Fondaparinux:
What are common adverse effects and why?
Haemorrhage ( lower risk may be with Fonda than with LMWH)
Bruising
Hyperkalaemia- effect on adrenal aldosterone secretion
Rarely: Immune reaction characterised by (HIT Heparin-induced thrombocytopenia)
less likely with LMWH than UFH and far less than with fondaparinux.
What are common interactions with heparin and fondaparinux?
Antithrombotic drugs and heparins has an additive effect sometimes desirable such as in treating ACS . Also associated with increased risk bleeding.
Who should be used prescribed with caution?
Risk of bleeding:
-clotting disorders
-severe uncontrolled hypertension
Withheld before invasive procedures(especially lumbar puncture and spinal anaesthesia)
Renal impairment-
LMWH and fonda
accumulate so lower dose or UFH should be used instead.
What is the treatment reverse heparin effects?
Major bleeding; protamine
Effective for UFH but less for LMWH and ineffective against fondaparinux.
What is treatment to reverse fondaparinux?
Andexanet Alpha but is unlicensed
What are dosages
-Dalteparin 5000 SC daily for VTE prophylaxis
- UFH preferred in renal impairment or when rapid onset and offset anticoagulation is required.
( heparin 5000 units SC 12 hourly for VTE prophylaxis)
What are monitoring requirements before and after starting?
FBC
clotting
renal profiles
In prolonged therapy (>4 days):
platelet count and serum potassium concentration should be monitored because the risk of HYPERKALAEMIA and THROMBOCYTOPOENIA increases with duration of therapy.
What is a sign of HIT? and should be done if suspected?
Significant decline in platelets
Seek specialist advice, stop heparin
What should be prescribed along side warfarin indicated for VTE?
LMWH because there is a delay in the onset of the anticoagulant effect while existing clotting factors are cleared.
