Venous Thromboembolism

Question 1

What are the main conditions contained within the umbrella of venous thromboembolism?

Answer 1

DVT and PE.

Question 2

What should all patient’s admitted to hospital be assessed for?

Answer 2

VTE risk.

Question 3

When admitted to hospital, which patients may be considered high risk of VTE?

Answer 3

Patients anticipated to have substantially reduced mobility, obese patients, patient’s with malignant disease, patients with a history of VTE, patients with a thrombophilic disorder, patients over 60.

Question 4

What pharmacological prophylaxis should be offered to patients at high risk of VTE when in hospital?

Answer 4

A low molecular weight heparin, unfractionated heparin (renal failure) or fondaparinux.

Question 5

How long should pharmacological prophylaxis of VTE in high-risk patients in hospital be continued for?

Answer 5

Until the patient is no longer considered to be at significant risk of VTE.

Question 6

When should mechanical prophylaxis of VTE be considered for high-risk patients in hospital?

Answer 6

For medical patients in whom pharmacological prophylaxis is contraindicated.

Question 7

How long should mechanical prophylaxis of VTE in high-risk patients in hospital be continued for?

Answer 7

Until the patient is sufficiently mobile.

Question 8

What can be considered for mechanical prophylaxis of VTE?

Answer 8

Anti-embolism stockings.

Question 9

What is the initial pharmacological treatment of DVT and PE?

Answer 9

A low molecular weight heparin or unfractionated heparin IV infusion. Warfarin is usually started at the same time.

Question 10

How long should a heparin, used for the initial pharmacological treatment of VTE, be continued for?

Answer 10

At least five days and until the INR is greater than or equal to two for at least 24 hours.

Question 11

How frequently is laboratory monitoring required when a patient is on heparins for VTE treatment?

Answer 11

Preferably on a daily basis.

Question 12

Can heparins be used in pregnancy and why?

Answer 12

Yes, they do not cross the placenta.

Question 13

Which heparins are preferred for use in pregnancy and why?

Answer 13

LMWHs as they carry a lower risk of osteoporosis and heparin-induced thrombocytopenia.

Question 14

When should treatment with heparins be stopped in pregnancy?

Answer 14

At the onset of labour, with speciality advice being sought.

Question 15

If haemorrhage occurs when a patient is being administered heparins what should be the first action taken?

Answer 15

The heparin should be withdrawn.

Question 16

If rapid reversal of anticoagulation is required after a patient has been administered heparins, what should be used?

Answer 16

Protamine sulphate (only partially reverses the effects on LMWHs).

Question 17

What is the difference between unfractionated heparins and LMWHs?

Answer 17

Unfractionated heparins act rapidly but have a short duration of action. LMWHs have a longer duration of action.

Question 18

Give some examples of LMWHs.

Answer 18

Dalteparin, tinzaparin, enoxaparin.

Question 19

Why are LMWHs generally preferred?

Answer 19

They carry a reduced risk of heparin-induced thrombocytopenia.

Question 20

Why are LMWHs generally more convenient?

Answer 20

Less frequent dosing (longer duration of action), reduced requirement for monitoring.

Question 21

Why are unfractionated heparins preferred for use in those patients with a high risk of bleeding?

Answer 21

Because their effects can be terminated rapidly by stopping the infusion.

Question 22

How long does it usually take for heparin-induced thrombocytopenia to present?

Answer 22

Five to ten days.

Question 23

In order to monitor for heparin-induced thrombocytopenia, what should be specifically monitored?

Answer 23

Platelet counts before and during treatment if given for longer than four days.

Question 24

What signs suggest a patient is suffering from heparin-induced thrombocytopenia?

Answer 24

30% reduction of platelet count, thrombosis, skin allergy.

Question 25

If heparin-induced thrombocytopenia occurs, what actions should be taken?

Answer 25

The heparin should be stopped and an alternative anticoagulant should be given. One should ensure the platelet count is returned to normal in those who require warfarin.

Question 26

How can heparins lead to hyperkalaemia?

Answer 26

Heparins inhibit aldosterone secretion which can result in hyperkalaemia.

Question 27

Which patients are at greater risk of hyperkalaemia when given heparins?

Answer 27

Patients with diabetes mellitus, chronic renal failure, acidosis, raised plasma potassium, taking potassium-sparing drugs.

Question 28

In patients at a greater risk of hyperkalaemia when using heparins, what should be monitored before and during treatment?

Answer 28

Plasma potassium concentration, especially if treatment is to last for longer than seven days.