Pulmonary Embolism Flashcards
What is a pulmonary embolism?
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.
Risk factors
Immobility Recent surgery Long haul flights Pregnancy Hormone therapy with oestrogen Malignancy Polycythaemia Systemic lupus erythematosus Thrombophilia
What is given to patients at risk of developing a pulmonary embolism?
Low molecular weight heparin such as enoxaparin unless contraindicated
Contraindications of low molecular weight haparin
Active bleeding or existing anticoagulation with warfarin or a NOAC.
What should all patients admitted into hospital be assessed for?
Their risk of venous thromboembolism
Presentation
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.
What does the Wells Score predict?
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.
Points in Wells Score
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
What to do if Wells Score is <4?
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.
What to do is Wells score is > 4?
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).
Diagnosis
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
What are the two main options for establishing a diagnosis?
CT pulmonary angiogram or ventilation–perfusion (VQ) scan.
Initial recommended treatment
The initial recommended treatment is apixaban or rivaroxaban.
Alternative treatmenr ==t
Low molecular weight heparin (LMWH) is an alternative where these are not suitable, or in antiphospholipid syndrome.
Examples are enoxaparin and dalteparin.
What are the options in long term anticoagulation in VTE (blood clots)?
The options for long term anticoagulation in VTE are warfarin, a NOAC (rixoban) or LMWH ( dalteparin, enoxaparin).
What is the target INR for warfarin?
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).
What are the three main options of NOACs or DOACs and when are they used?
The main three options are apixaban, dabigatran and rivaroxaban.
They are an alternative option for anticoagulation that does not require monitoring.
What is the first lune treatment in pregnant or cancer patients?
Low molecular weight heparins (LMWH)
Dalteparin, enoxaparin
How long should anticoagulation be continued for?
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)
When is thrombolysis used?
Where there is a massive PE with haemodynamic compromise there is a treatment option called thrombolysis.
When is there haemodynamic compromise?
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.
What is thrombolysis?
Injecting a fibrinolytic medication (they break down fibrin) that rapidly dissolves clots.
What are the risks of thrombolysis and when is it used?
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.
What are examples of thrombolytic agents?
Streptokinase
Alteplase
Tenecteplase
What are the two ways theombolysis can be performed?
Intravenously using a peripheral cannula.
Directly into the pulmonary arteries using a central catheter. This is called catheter-directed thrombolysis.
Contraindicated of thromboylsis?
Previous intracranial haemorrhage, recent ischaemic stroke (<3 months), recent head injury, recent surgery, current active bleeding or bleeding disorder.
