Deep Vein Thrombosis Flashcards
What is deep vein thrombosis (DVT)?
It is defined as a condition in which there is formation of a blood clot in the venous circulation
In which region of the body, does deep vein thrombosis tend to develop?
Deep veins of the lower limb
What twelve risk factors are associated with deep vein thrombosis?
Older Age
Family History
Obesity
Pregnancy
Immobility
Hospitalisation
Malignancy
Thrombophilia
Antiphospholipid Syndrome
Polycythaemia
Drug Administration
Central Venous Catheter
Which six drugs are associated with deep vein thrombosis?
Combined Oral Contraceptive Pill
Hormone Replacement Therapy
Tamoxifen
Raloxifene
Antipsychotics
Anaesthesia
What are the four clinical features of deep vein thrombosis?
Calf Tenderness
Calf Swelling > 3cm
Dilated Superficial Veins
Lower Limb Pitting Oedema
How do we measure calf swelling, in suspected cases of deep vein thrombosis?
We measure the circumference of the calf 10cm below the tibial tuberosity and compare this measurement with the asymptomatic calf
What three investigations are used to diagnose deep vein thrombosis?
Wells Score
D-Dimer Blood Test
Proximal Leg Vein Ultrasound Scans
How is the ‘Wells Score’ used to investigate pulmonary embolism?
It is used to predict the risk of deep vein thrombosis in suspected cases
What are the ten criteria of the ‘Wells Score’?
Active Cancer = Ongoing Treatment, < 6 Months, Palliative (1 Point)
Paralysis, Paresis, Plaster Immobilisation Of Lower Extremities (1 Point)
Bedrest > 3 Days, Major Surgery Within 12 Weeks Requiring General/Regional Anaesthesia (1 Point)
Localised Tenderness Of Deep Venous System (1 Point)
Entire Swollen Leg (1 Point)
Calf Swelling > 3cm Compared To Asymptomatic Side (1 Point)
Pitting Oedema Confined To Symptomatic Leg (1 Point)
Collateral Superficial Veins, Non-Varicose (1 Point)
Previously Document Deep Vein Thrombosis (1 Point)
An Alternative Diagnosis Is At Least As Likely As Deep Vein Thrombosis (-2 Points)
What does a ‘Wells Score’ > 2 indicate?
It indicates that a diagnosis of deep vein thrombosis is likely
What should be conducted following a ‘Wells Score’ > 2?
A proximal leg vein ultrasound scan should be conducted within 4 hours
What should be conducted when the proximal leg vein ultrasound scan is positive for deep vein thrombosis - Wells Score > 2?
A deep vein thrombosis diagnosis is obtained and anticoagulant treatment should be commenced
What should be conducted when the proximal leg vein ultrasound scan is negative for deep vein thrombosis - Wells Score > 2?
D-Dimer blood tests should be conducted
When these blood tests are negative, an alternative diagnosis should be considered
What should be conducted when the proximal leg vein ultrasound scan cannot be conducted within 4 hours - Wells score > 2?
The D-Dimer blood test should be conducted and interim therapeutic direct oral anticoagulation (DOAC) should be administered, whilst waiting
This ultrasound scan should be performed within 24 hours
What should be conducted when the proximal leg vein ultrasound scan is negative and then the D-Dimer blood tests are positive- Wells score > 2?
It is recommended that the interim therapeutic anticoagulation is stopped, and a repeat ultrasound scan is conducted 6 – 8 days later
What does a ‘Wells Score’ < 1 indicate?
It indicates that a diagnosis of deep vein thrombosis is unlikely
What should be conducted when a ‘Wells Score’ < 1?
The D-Dimer blood test can be conducted within 4 hours
What should be conducted when the D-Dimer blood test results are negative - Wells Score < 1?
An alternative diagnosis should be considered
What should be conducted when the D-Dimer blood test results are positive - Wells Score < 1?
A proximal leg vein ultrasound scan should be conducted within 4 hours
What should be conducted when the proximal leg vein ultrasound scan cannot be conducted within 4 hours - Wells Score < 1?
An interim therapeutic anticoagulation should be administered whilst waiting
This ultrasound scan should be performed within 24 hours
When are D-Dimer blood tests used to investigate deep vein thrombosis?
They are used to exclude a diagnosis of deep vein thrombosis when there is low clinical suspicion
However, due to the fact that it can be elevated in other conditions, it cannot provide a definitive diagnosis
What D-Dimer blood test result indicates deep vein thrombosis?
> 0.5 ug/mL
What is the feature of deep vein thrombosis on proximal leg vein ultrasound scans?
There is an absence of blood flow to the affected limb
What are the three pharmacological management options of deep vein thrombosis?
Oral Anticoagulants (DOACs)
Low Molecular Weight Heparin (LMWH)
Vitamin K Antagonists (VKAS)
When are direct oral anticoagulants (DOACs) used to manage deep vein thrombosis?
They are the first line management option of deep vein thrombosis, which should be offered once a diagnosis is suspected and continued when the diagnosis is confirmed
What are the two first line direct oral anticoagulants used to manage deep vein thrombosis?
Apixaban
Rivaroxaban
What are the two second line direct oral anticoagulants used to manage deep vein thrombosis? When are they administered?
Dabigatran
Edoxaban
They are administered following low molecular weight heparin administration
When is low molecular weight heparin (LMWH) used to manage deep vein thrombosis?
It is the second line management option of deep vein thrombosis
Name three low molecular weight heparins used to manage deep vein thrombosis
Dalteparin
Enoxaparin
Tinzaparin
Describe the course of low molecular weight heparin used to manage deep vein thrombosis
They should be administered for a 5 – 10 days, followed by direct oral anticoagulants OR vitamin K antagonists for a period of 3 - 6 months
When are vitamin K antagonists (VKAs) used to manage deep vein thrombosis?
They are the second line management option of deep vein thrombosis – which are administered following low molecular weight heparin administration
Name a vitamin K antagonist used to manage deep vein thrombosis
Warfarin
What is the pharmacological management option of deep vein thrombosis in active cancer patients?
Direct oral anticoagulant - unless this is contraindicated
What are the three pharmacological management options of deep vein thrombosis in severe renal impairment eGFR < 15?
Low Molecular Weight Heparin
Unfractioned Heparin
Low Molecular Weight Heparin Followed By Vitamin K Antagonist
What is the pharmacological management option of deep vein thrombosis in antiphospholipid syndrome patients?
Low Molecular Weight Heparin Followed By Vitamin K Antagonist
What is provoked deep vein thrombosis?
It is deep vein thrombosis secondary to an obvious precipitating event
How long is anticoagulant course treatment in provoked deep vein thrombosis?
3 Months
In which circumstance is provoked deep vein thrombosis treated with an anticoagulation treatment course of 6 months?
Active cancer
What is an unprovoked deep vein thrombosis?
It is deep vein thrombosis not due to an obvious precipitating event
How long is anticoagulant course treatment in unprovoked deep vein thrombosis?
6 months
What is a high risk factor of deep vein thrombosis in pregnant patient?
Previous history of deep vein thrombosis
What prophylactic management should be administered in pregnant patients with high risk factors for deep vein thrombosis?
Low molecular weight heparin should be administered throughout the antenatal period, alongside expert input
What are the four intermediate risk factors of deep vein thrombosis in pregnant patients?
- Recent Hospitalisation
- Recent Surgery
- Co-Morbidities
- High Risk Thrombophilia
What prophylactic management should be administered in pregnant patients with intermediate risk factors for deep vein thrombosis?
Low molecular weight heparin should be considered throughout the antenatal period, alongside expert input
What are the eleven low risk factors of deep vein thrombosis in pregnant patients?
- Age > 35 Years Old
- Deep Vein Thrombosis Family History
- Parity > 3
- Multiple Pregnancy
- In Vitro Fertilisation Pregnancy
- Pre-Eclampsia
- Immobility
- Low Risk Thrombophilia
- Gross Varicose Veins
- Body Mass Index > 30
- Smoker
What prophylactic management should be administered when individuals have three low risk factors of deep vein thrombosis?
Low molecular weight heparin should be administered from 28 weeks’ gestation and continued until 6 weeks postnatal
What prophylactic management should be administered when individuals have more than four low risk factors of deep vein thrombosis?
Immediate management with low molecular weight heparin should be administered until 6 weeks postnatal
Which two pharmacological management options of deep vein thrombosis are contraindicated in pregnancy?
Direct Oral Anticoagulants
Warfarin
When is prophylactic management of deep vein thrombosis administered in hospitalised patients?
When the deep vein thrombosis risk is deemed greater than the bleeding risk – determined on an individual case basis
What is the prophylactic management option of deep vein thrombosis in medical hospitalised patients?
Pharmacological anticoagulation, such as fondaparinux, low molecular weight heparin or unfractioned heparin should be administered
What is the prophylactic management option of deep vein thrombosis in surgical hospitalised patients?
The anti-embolism stockings are the first line management option
However, when deemed at high risk pharmacological management should be additionally administered
The post-surgical pharmacological prophylaxis administered is dependent upon the surgical procedure
What is the complication assoicated with deep vein thrombosis?
Post-Thrombotic Syndrome
What is post-thrombotic syndrome?
It is defined as a condition in which there is venous outflow obstruction and venous insufficiency, resulting in chronic venous hypertension
When does post-thrombotic syndrome develop after deep vein thrombosis?
> Years
What are the five clinical features of post-thrombotic syndrome?
Calf Pain
Calf Swelling
Varicose Veins
Varicose Ulceration
Pruritus
What are the two management options of post-thrombotic syndrome?
Limb Elevation
Wear Compression Stockings
