VTE

Question 1

What is the difference between DVT and PE

Answer 1

DVT -Blood clot in a deep vein

P.E- detachment of blood clot that travels to the lungs and blocks pulmonary artery.

Question 2

Which patients are at risk of VTE

Answer 2

Immobile
Obese
Malignant disease
History of VTE
Over 60
HRT/contraceptive
varicose veins with phlebitis
Pregnancy
Critical care
significant co-morbidities
relative with VTE

Question 3

Who are at risk of bleeding?

Answer 3

Patients on anticoagulants
Systolic hypertension
Thrombocytopenia (low platelet)
Acute stroke
Bleeding disorders
Acquired: liver disease
Inherited:haemophillia

Question 4

What are different forms of prophylaxis against blot clots?

Answer 4

Mechanical prophylaxis:
compression stockings
Pharmacological VTE prophylaxis:
Parenteral anticoagulants and DOACs

Question 5

What are examples of parenteral anticoagulants?

Answer 5

-LMWH
-Unfractionated Heparin in renal failure
-Fondaparinux

Question 6

When are DOACs used for VTE prophylaxis?

Answer 6

Prophylaxis after knee/hip replacement surgery

Edoxaban: treatment and prevention recurrent VTE.

Question 7

How long would you give VTE prophylaxis for following surgery?

Answer 7

General-5-7 days
Major cancer surgery in abdomen or pelvis- 28 days
Knee/hip surgery: extended duration

Question 8

What is TREATMENT of VTE?and what is length of treatment?

Answer 8

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)

Question 9

What VTE is used in pregnancy and why?

Answer 9

LMWH
Lower risk of osteoporosis and heparin induced thrombocytopenia (HIT)

Question 10

HEPARIN:

Heparin and Fondaparinux (parenteral)
What are common indications?

Answer 10

Can be given in ACS to reduce clot progression

Question 11

HEPARIN:

What is the mechanism of action?

Answer 11

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

Question 12

What is fondaparinux?

Answer 12

A synthetic pentasaccharide that mimics the sequence of the binding site of heparin to antithrombin and is very specific for factor Xa

Question 13

Heparin and Fondaparinux:

What are common adverse effects and why?

Answer 13

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.

Question 14

What are common interactions with heparin and fondaparinux?

Answer 14

Antithrombotic drugs and heparins has an additive effect sometimes desirable such as in treating ACS . Also associated with increased risk bleeding.

Question 15

Who should be used prescribed with caution?

Answer 15

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.

Question 16

What is the treatment reverse heparin effects?

Answer 16

Major bleeding; protamine
Effective for UFH but less for LMWH and ineffective against fondaparinux.

Question 17

What is treatment to reverse fondaparinux?

Answer 17

Andexanet Alpha but is unlicensed

Question 18

What are dosages

Answer 18

-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)

Question 19

What are monitoring requirements before and after starting?

Answer 19

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.

Question 20

What is a sign of HIT? and should be done if suspected?

Answer 20

Significant decline in platelets

Seek specialist advice, stop heparin

Question 21

What should be prescribed along side warfarin indicated for VTE?

Answer 21

LMWH because there is a delay in the onset of the anticoagulant effect while existing clotting factors are cleared.