Deep Vein Thrombus (DVT) Flashcards
DVT is caused by the partial or total occlusion of which vein(s)
The deep vein(s)
What deep veins are commonly occluded in DVT
Commonly affects the lower limbs but can affect any deep vein e.g. thigh, pelvis or abdomen
DVT is commonly seen alongside what other condition
Pulmonary embolism (PE)
DVT is rarely life threatening but it can when can it become life threatening
It can cause pulmonary embolism (PE)
Describe how the DVT can cause a PE
DVT occurs when a thrombus forms in the deep veins
an emboli from the thrombus of the deep veins can travel to the right side of the heart and into the lungs where it becomes lodged in the pulmonary arteries causing the PE
What causes Venous thromboembolism (VTE)
Occurs as a result of a clot (thrombi) developing in the circulation
Venous thromboembolism (VTE) encompasses two conditions.
Name the two conditions?
Pulmonary embolism (PE)
Deep vein thrombosis (DVT)
Name some of the risk factors for DVT
Active cancer
Trauma
Major surgery
Hospitalisation
Immobilisation
Pregnancy
Oral contraceptive use
NOTE: DVT can be unprovoked (idiopathic) and occur in the absence of any identifiable risk factors
What are some of the clinical features of DVT
Almost always unilateral
Asymmetrical leg swelling
Unilateral leg pain
Dilation or distension of superficial veins
Red or discoloured skin
Can also be asymptomatic
Define Thrombophilias
Refers to conditions that predispose patients to develop blood clots.
Give an example of a Thrombophilias
Antiphospholipid syndrome
Antithrombin deficiency
Protein C or S deficiency
What is the Probability Tool for PE/VTE
Wells Score
When is the Wells Score used
Used to predict the likelihood of a DVT/PE
When interpretating the Wells Score.
A score of what makes a DVT likely
Wells Score 2 or more
When interpretating the Wells Score.
A score of what makes a DVT unlikely
1 or less
Name some of the components of the Wells Score
Active cancer
Paralysis, paresis or recent plaster immobilisation of the lower extremities
Recently bedridden for >3 days or major surgery within 12 weeks
Localised tenderness along the distribution of the deep venous system
Swelling of entire leg
Calf swelling (>3 cm larger than asymptomatic side)
Pitting oedema confined to the symptomatic leg
Prominent superficial veins (non-varicose)
Previously history of DVT or PE
An alternative diagnosis is at least as likely as DVT
What are the two key investigations for DVT
Doppler ultrasound
D-dimer (although not always needed)
When is the doppler ultrasound used in investigating DVT
Wells score DVT likely = Doppler ultrasound done first without the need for a D-dimer first
Wells score DVT unlikely = require D-dimer first and only if that comes back positive should they undergo a doppler ultrasound
If a doppler ultrasound is unable to complete within 4 hours of DVT suspicion. What should be given whilst they await the scan?
Interim anticoagulation
Wells score likely
Initialy scan negative
d-dimer positive.
What is the next stage in investigating DVT?
Interim anticoagulation should be stopped and a repeat proximal leg vein ultrasound in 6-8 days
Patient has a:
Wells score likely
Initialy scan negative
d-dimer positive
The next step is stopping interim anticoagulation and repeating proximal leg vein ultrasound when?
6-8 days
For patients with a Well score likely.
What is the next step in investigating DVT
Ultrasound (if available within 4 hours)
If over 4 hours, give interim anticoagulation whilst they await investigations
For patients with a Well score unlikely.
What is the next step in investigating DVT
D-dimer
D-dimer is an important investigation for DVT.
At what stage is D-dimer used
Used when the Wells score DVT unlikely or if the initial ultrasound scan is negative
How specific and sensitive is d-dimer in DVT
Highly sensitive but not specific i.e. can reliably exclude VTE but cannot confirm it
Venous thromboembolism (VTE) is a cause of a raised d-dimer however it is not the only cause.
Name some other conditions that can cause a raised d-dimer
Pneumonia
Malignancy
Heart failure
Surgery
Pregnancy
Wells score likely
Doppler Ultrasound negative
What is the next step in investigating DVT
Interim anticoagulation should be stopped and a repeat proximal leg vein ultrasound in 6-8 days
Wells score unlikely
D-dimer negative
What is the next step in investigating DVT
Unlikely DVT
Think other diagnosis
Wells score unlikely
D-dimer positive
What is the next step in investigating DVT
Doppler ultrasound
What is the cornerstone treatment in the initial management of DVT
Anticoagulation
Should be started immediately in patients where:
- DVT or PE is suspected
- There is a delay in getting doppler ultrasound scan
In most cases what is the anticoagulant of choice for the immediate management of DVT
Direct oral-acting anticoagulants (DOAC) e.g. apixaban or rivaroxaban
After initial management, anticoagulant therapy is required to continue for a period of time to prevent future DVT/PE.
What are the anticoagulation options for these patients
DOAC
Low molecular weight heparin (LMWH)
Vitamin K antagonists i.e. warfarin
After initial management, anticoagulant therapy is required to continue for a period of time to prevent future DVT/PE.
What is the anticoagulant used in the majority of cases
DOACs as it does not require monitoring
What is the first-line anticoagulant in pregnancy [managing DVT]
Low molecular weight heparin (LMWH)
What is the first-line anticoagulant in antiphospholipid syndrome [managing DVT]
Warfarin
After initial management, anticoagulant therapy is required to continue for a period of time to prevent future DVT/PE.
What is the duration of this therapy?
3 months – for those with reversible cause
Beyond 3 months (typically 6 months) – if the cause is unclear, recurrent VTE, irreversible cause
3-6 months – active cancer
After initial management, anticoagulant therapy is required to continue for a period of time to prevent future DVT/PE.
What is the duration of this therapy if there is a reversible cause of the DVT
3 months
After initial management, anticoagulant therapy is required to continue for a period of time to prevent future DVT/PE.
What is the duration of this therapy if there is a cause is unclear, recurrent VTE, irreversible cause
Beyond 3 months (typically 6 months)
After initial management, anticoagulant therapy is required to continue for a period of time to prevent future DVT/PE.
What is the duration of this therapy for those with active cancer
6 months
What is a complication of DVT
Post-thrombotic syndrome
Presence of chronic swelling, pain and skin discoloration. In severe cases it can lead to ulcers and gangrene.
