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?

Options:
explanation: 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
name: 6 months
label: c
answer: no
explanation: 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
name: 3 months
label: a
answer: yes
explanation: 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
name: 1 year
label: d
answer: no
explanation: 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
name: 4 weeks
label: b
answer: no
explanation: 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
name: Lifelong
label: e
answer: no

Correct answer: a