Pulmonary Embolism

Question 1

What is a pulmonary embolism?

Answer 1

A pulmonary embolism (PE) is when a blood clot in the pulmonary arterial vasculature develops, usually from an underlying deep vein thrombosis (DVT) of the lower limbs.

Question 2

Risk factors

Answer 2

Immobility
Recent surgery
Long haul flights
Pregnancy
Hormone therapy with oestrogen
Malignancy
Polycythaemia
Systemic lupus erythematosus
Thrombophilia

Question 3

What is given to patients at risk of developing a pulmonary embolism?

Answer 3

Low molecular weight heparin such as enoxaparin unless contraindicated

Question 4

Contraindications of low molecular weight haparin

Answer 4

Active bleeding or existing anticoagulation with warfarin or a NOAC.

Question 5

What should all patients admitted into hospital be assessed for?

Answer 5

Their risk of venous thromboembolism

Question 6

Presentation

Answer 6

Shortness of breath
Cough with or without blood (haemoptysis)
Pleuritic chest pain
Hypoxia
Tachycardia
Raised respiratory rate
Low grade fever
Haemodynamic instability causing hypotension

There may also be signs and symptoms of a deep vein thrombosis such as unilateral leg swelling and tenderness.

Question 7

What does the Wells Score predict?

Answer 7

The risk of a patient presenting with symptoms actually having a DVT or pulmonary embolism.

It takes in to account risk factors such as recent surgery and clinical findings such as tachycardia (heart rate >100) and haemoptysis.

Question 8

Points in Wells Score

Answer 8

3 points:
Clinical signs and symptoms of a deep vein thrombosis (DVT)
If no alternative diagnosis is more likely than a PE

1.5 points:
Tachycardia (heart rate >100 beats/minute)
If the patient has been immobile for more than 3 days or has had major surgery within the last month
If the patient has had a previous PE or DVT

1 point:
If the patient presents with haemoptysis
If there is an active malignancy

Question 9

What to do if Wells Score is <4?

Answer 9

If the Well’s score is 4 or less the D-dimer should be measured.

The D-dimer has a high negative predictive value but a low specificity so is only useful if the clinical suspicion of a PE is low.

Question 10

What to do is Wells score is > 4?

Answer 10

If the Well’s score is more than 4, CT pulmonary angiogram is required.

Low-molecular weight heparin is typically administered in the interim if the clinical suspicion of a PE is high (and should certainly be administered if there is delay in performing the CTPA).

Question 11

Diagnosis

Answer 11

NICE recommend assessing for alternative causes with a:

History
Examination
Chest xray

Perform a Wells score and proceed based on the outcome:

Likely: perform a CT pulmonary angiogram
Unlikely: perform a d-dimer and if positive perform a CTPA

Question 12

What are the two main options for establishing a diagnosis?

Answer 12

CT pulmonary angiogram or ventilation–perfusion (VQ) scan.

Question 13

Initial recommended treatment

Answer 13

The initial recommended treatment is apixaban or rivaroxaban.

Question 14

Alternative treatmenr ==t

Answer 14

Low molecular weight heparin (LMWH) is an alternative where these are not suitable, or in antiphospholipid syndrome.

Examples are enoxaparin and dalteparin.

Question 15

What are the options in long term anticoagulation in VTE (blood clots)?

Answer 15

The options for long term anticoagulation in VTE are warfarin, a NOAC (rixoban) or LMWH ( dalteparin, enoxaparin).

Question 16

What is the target INR for warfarin?

Answer 16

The target INR for warfarin is 2-3. When switching to warfarin continue LMWH for 5 days or the INR is 2-3 for 24 hours on warfarin (whichever is longer).

Question 17

What are the three main options of NOACs or DOACs and when are they used?

Answer 17

The main three options are apixaban, dabigatran and rivaroxaban.

They are an alternative option for anticoagulation that does not require monitoring.

Question 18

What is the first lune treatment in pregnant or cancer patients?

Answer 18

Low molecular weight heparins (LMWH)

Dalteparin, enoxaparin

Question 19

How long should anticoagulation be continued for?

Answer 19

Continue anticoagulation for:

3 months if there is an obvious reversible cause (then review)
Beyond 3 months if the cause is unclear, there is recurrent VTE or there is an irreversible underlying cause such as thrombophilia. This is often 6 months in practice.
6 months in active cancer (then review)

Question 20

When is thrombolysis used?

Answer 20

Where there is a massive PE with haemodynamic compromise there is a treatment option called thrombolysis.

Question 21

When is there haemodynamic compromise?

Answer 21

Signs of hemodynamic compromise include postural changes with dyspnea, tachypnea, and tachycardia.

An drop in systolic blood pressure of more than 10 mm Hg or an increase in heart rate of more than 10 beats per minute is indicative of at least 15% of blood volume loss.

Question 22

What is thrombolysis?

Answer 22

Injecting a fibrinolytic medication (they break down fibrin) that rapidly dissolves clots.

Question 23

What are the risks of thrombolysis and when is it used?

Answer 23

There is a significant risk of bleeding which can make it dangerous. It is only used in patients with a massive PE where the benefits outweigh the risks.

Question 24

What are examples of thrombolytic agents?

Answer 24

Streptokinase
Alteplase
Tenecteplase

Question 25

What are the two ways theombolysis can be performed?

Answer 25

Intravenously using a peripheral cannula.

Directly into the pulmonary arteries using a central catheter. This is called catheter-directed thrombolysis.

Question 26

Contraindicated of thromboylsis?

Answer 26

Previous intracranial haemorrhage, recent ischaemic stroke (<3 months), recent head injury, recent surgery, current active bleeding or bleeding disorder.