QuestionSBA
QuestionChoice
This patient has a provoked DVT from a long haul flight. NICE guidance states the patient should receive 3 months of anticoagulation with apixaban or rivaroxaban, unless contraindicated. 6 months is the course length for patients with provoked DVT who have underlying malignancy - this is due to the prothrombotic nature of various malignancies. NB - these patients are often kept on anticoagulants _ad infinitum_ if their cancer is incurable, due to the prothrombotic tendencies
33200
c
6 months
QuestionChoice
For a provoked deep vein thrombosis (DVT) or pulmonary embolism (PE) with no other risk factors, such as cancer or coagulation disorder, the NICE recommendation is to complete 3 months of anticoagulation (apixaban/rivaroxaban). From then, if the provoking factor is no longer present (in this case a long-haul flight) and the clinical course has been uncomplicated, then you can consider stopping anticoagulation. If the patient has cancer with a provoked DVT, then the anticoagulation treatment should last 3-6 months. For patients with unprovoked DVTs, then further investigation needs to be conducted while on anticoagulation to determine the cause of the DVT such as antiphospholipid syndrome, previously unknown underlying malignancy, or hereditary thrombophilia, among others
33198
a
3 months
QuestionChoice
This patient has a provoked DVT from a long haul flight. NICE guidance states the patient should receive 3 months of anticoagulation with apixaban or rivaroxaban, unless contraindicated. There is no specific guidance for a course to be one year. Course lengths are 3 months for provoked DVT without malignancy, 6 months in those with malignancy, and continued lifelong in those with unprovoked DVT unless a cause is found and treated appropriately. Those on anticoagulation should be reviewed at least once a year by the GP for ongoing bleeding/clotting risks
33201
d
1 year
QuestionChoice
This patient has a provoked DVT from a long haul flight. NICE guidance states the patient should receive 3 months of anticoagulation with apixaban or rivaroxaban, unless contraindicated. 4 weeks is the post-operative course length of prophylactic low molecular weight heparin after major operations within the abdomen (28 days) or the spine (30 days). This is to protect against DVTs from reduced mobility
33199
b
4 weeks
QuestionChoice
This patient has a provoked DVT from a long haul flight. NICE guidance states the patient should receive 3 months of anticoagulation with apixaban or rivaroxaban, unless contraindicated. A patient would be kept on lifelong treatment if they developed an unprovoked DVT and the cause, such as antiphospholipid syndrome or incurable malignancy, were irreversible. The patient may also be kept on lifelong anticoagulation if the cause of their unprovoked DVT has not been found, but the risk of venous thromboembolism outweighed the bleeding risk
33202
e
Lifelong
QuestionComment
Got the right answer as assumed quested would define this as provoked but this doesn't seem to align with the definition of provoked pe from any clinical resources.
8295
User
subscriber
Zebras Anterior
QuestionComment
Questionable whether this is a 'provoked' PE - reconsider this question
9174
User
subscriber
Bradykinin Gastro
QuestionComment
a 36 year old man should not have a PE from a flight unless he has an underlying condition 
26054
User
subscriber
RNA Relapse
Concept
Chapter
# Definition

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.

# Epidemiology of pulmonary embolism (PE)

2300 people died as a result of a pulmonary embolism in the UK in 2012, representing 2% of all deaths from lung diseases.

# Presentation of a PE

**Symptoms**

- Sudden-onset shortness of breath, pleuritic chest pain, and haemoptysis (this is the 'typical' triad, although note that all three features are rarely present).

- A massive pulmonary embolism may present with the above and syncope/shock.

- A small pulmonary embolism may be asymptomatic.

**Signs**

- Classically tachypnoea, tachycardia and hypoxia is present. There may be low-grade pyrexia. Tachycardia may be the only presenting sign.

- Note that a small pulmonary embolism may result in a normal examination.

- A massive pulmonary embolism may present with hypotension, cyanosis, and signs of right heart strain (such as a raised JVP, parasternal heave, and loud P2).

It is important to look for signs of a concomitant deep vein thrombosis (a unilaterally swollen, tender calf).

# ECG findings

ECG: Normal or sinus tachycardia. In a massive PE there may be evidence of right-heart strain (with P pulmonale, right axis deviation, right bundle branch block, and non-specific ST/T wave changes). The classic S1Q3T3 (deep S waves in lead I, pathological Q waves in lead III, and inverted T waves in lead III) is relatively uncommon (<20% of patients).

# Blood tests in PE

ABG: This may be normal or show a type 1 respiratory failure (hypoxia without hypercapnia) and/or a respiratory alkalosis (due to hyperventilation secondary to hypoxia).

Remember the baseline tests such as FBC (the patient may be anaemic if the PE has caused haemoptysis), CRP may be raised, U&E (to assess renal function before CTPA), clotting function (important if the patient is to be started on LMWH/Warfarin).

Special tests include D-dimer (this is highly non-specific but has a 95% negative predictive value i.e. it is useful in ruling out a PE if negative).

# Imaging Investigations in PE

Chest x-ray: this is typically normal in PE but possible findings include _Fleischner sign_ (an enlarged pulmonary artery), _Hampton's hump_ (a peripheral wedge shaped opacity), and _Westermark's sign_ (regional oligaemia). The chest x-ray is helpful in ruling out differentials (e.g. pneumonia, pneumothorax).

CT pulmonary angiogram (CTPA): this is the diagnostic test of choice for a PE and will show a filling defect in the pulmonary vasculature. Note that a V/Q scan is preferred if the patient has renal impairment, contrast allergy or is pregnant.

Lower limb Duplex: helpful if a DVT is thought to be the cause of the PE (note this investigation is first-line - before a CTPA - in pregnancy).

Bedside echocardiogram: this is used if the patient is thought to have a massive PE (signs of right heart strain/hypotension), in order to assess suitability for thrombolysis.

# Well's scoring system

The Well's score is a useful tool for risk stratifying patients with a suspected PE.

Points are allocated as follows:

- 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

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.

A low D-dimer excludes a PE. A raised D-dimer is an indication for diagnostic imaging (by CTPA or V/Q scan).

If the Well's score is more than 4 further diagnostic imaging 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).

# Acute management of a PE

In the emergency department the patient should be assessed using the DR ABCDE approach:

- Airway: likely to be patent.
- Breathing: the patient may be tachypnoeic and hypoxic. Oxygen should be administered.
- Circulation: the patient may be tachycardic. Signs of right heart strain are suggestive of a sub-massive PE. Hypotension is suggestive of a massive PE. Consider intravenous fluids if the systolic blood pressure is <90 mmHg.
- Disability: likely to be unremarkable.
- Exposure: the patient may have a low grade pyrexia. It is important to check for signs of a deep vein thrombosis (DVT). Consider analgesia at this stage if required.

Thrombolysis (an intravenous bolus of Alteplase) is indicated in a massive PE (features of haemodynamic instability). There is debate over whether it should be administered in a sub-massive PE.

# Medical management of a PE

Anticoagulation should be administered.

In the outpatient setting, direct oral anticoagulants such as apixaban or rivaroxaban should be started.

If neither of the above are suitable, dabigatran, edoxaban or warfarin can be considered. Low molecular weight heparin should be continued for at least 5 days and until 48 hours of therapeutic INR (>2) has been achieved if using warfarin. If using dabigatran or edoxaban then LMWH should be used for 5 day prior.

The duration of anticoagulation treatment depends on the aetiology of the PE. A provoked PE (identifiable risk factors e.g. surgery, peri-partum) should be treated for 3 months. An unprovoked PE should be treated for 6 months. If there is an ongoing cause (e.g. a thrombophilia) the patient should be treated for life.

Recurrence of a VTE in a patient already on warfarin requires an increase in the target INR (to 3-4).

In the inpatient/emergency setting, low molecular weight heparin is usually started instead as it is shorter acting.

# Interventional management of a PE

Embolectomy may be considered in patients with a massive PE when thrombolysis is contraindicated.

An inferior vena cava filter may be considered in patients with recurrent DVTs on Warfarin or patients in which anticoagulation is contraindicated.

# References

[Click for the NICE Guidelines](https://www.nice.org.uk/guidance/ng158)
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Pulmonary embolism
Topic
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Respiratory Physiology
6640
A 32-year-old man presents to accident and emergency with acute right-sided pleuritic chest pain and haemoptysis. He flew to the UK from South Africa yesterday and since then has had persistent pleuritic chest pain. He has also noticed new swelling of his right calf over the same period.

He has no known past medical history and is otherwise fit and well.

Electrocardiogram shows sinus tachycardia. He is haemodynamically stable.

CT pulmonary angiogram (CTPA) reveals a right lower lobe segmental pulmonary embolism (PE). Ultrasound doppler of his right calf reveals deep vein thrombosis (DVT) in his right popliteal vein.

You decide to start him on apixaban.

Which of the following is the most appropriate anticoagulation course length?
a