Deep Vein Thrombosis Flashcards by amo x

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

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In which region of the body, does deep vein thrombosis tend to develop?

Deep veins of the lower limb

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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

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Which six drugs are associated with deep vein thrombosis?

Combined Oral Contraceptive Pill

Hormone Replacement Therapy

Tamoxifen

Raloxifene

Antipsychotics

Anaesthesia

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What are the four clinical features of deep vein thrombosis?

Calf Tenderness

Calf Swelling > 3cm

Dilated Superficial Veins

Lower Limb Pitting Oedema

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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

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What three investigations are used to diagnose deep vein thrombosis?

Wells Score

D-Dimer Blood Test

Proximal Leg Vein Ultrasound Scans

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How is the ‘Wells Score’ used to investigate pulmonary embolism?

It is used to predict the risk of deep vein thrombosis in suspected cases

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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)

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What does a ‘Wells Score’ > 2 indicate?

It indicates that a diagnosis of deep vein thrombosis is likely

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What should be conducted following a ‘Wells Score’ > 2?

A proximal leg vein ultrasound scan should be conducted within 4 hours

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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

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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

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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

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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

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What does a ‘Wells Score’ < 1 indicate?

It indicates that a diagnosis of deep vein thrombosis is unlikely

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What should be conducted when a ‘Wells Score’ < 1?

The D-Dimer blood test can be conducted within 4 hours

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What should be conducted when the D-Dimer blood test results are negative - Wells Score < 1?

An alternative diagnosis should be considered

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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

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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

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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

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What D-Dimer blood test result indicates deep vein thrombosis?

> 0.5 ug/mL

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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