VTE Flashcards by Ella Oakley

What does a venous thrombus primarily consist of?

Fibrin and RBCs

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Within what timeframe does hospital-acquired VTE occur following hospital admission?

Within 90 days

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What can happen if a venous thrombus breaks off? 

It can cause a pulmonary embolism

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What is thrombophlebitis?

Superficial vein thrombosis

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How much greater is the risk of VTE in opioid drug misusers compared to the general population?

100x greater

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What is the approximate increased risk of DVT associated with varicose veins?
What is the approximate increased risk of PE associated with varicose veins?

5-fold increased risk
1.7 increased risk

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What is the risk of VTE for flights lasting 4-8 hours? What is the risk of VTE for flights lasting longer than 8 hours? How long after travel can VTE be attributed to the journey?

1 in 5,000
1 in 200
Up to 8 weeks

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What are some risk factors for VTE?

Major surgery
Active malignancy
Previous unprovoked VTE

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What type of assessment is the Well’s score for DVT?

Objective

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What percentage of DVT patients experience leg pain? What percentage of DVT patients experience swelling? What percentage of DVT patients experience localized tenderness?

80-90%
80%
75-85%

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What percentage of DVT patients have prominent collateral superficial veins? What percentage of DVT patients experience redness? What percentage of PEs begin as DVTs?

30%
25%
80%

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What are some factors that contribute to PE?

Stasis
Local hypercoagulability
Endothelial injury
Infection
Oestrogens
Pregnancy
Cancer

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What percentage of PE patients present with the classical triad of pleuritic chest pain, dyspnoea, and haemoptysis?

<10%

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What percentage of PE patients have no major risk factors? What percentage of PE patients have clinical signs of DVT?

40%
15%

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What are the CXR and ECG findings in PE patients? What are some differentials of PE?

Non-specific
Respiratory infection, heart failure, COPD exacerbation

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What percentage of PE patients experience breathlessness? What percentage of PE patients experience hypoxia? What percentage of PE patients experience tachycardia?

80%
70%
65-70%

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What percentage of PE patients experience pleuritic chest pain? What percentage of PE patients experience haemoptysis? What percentage of PE patients experience haemodynamic compromise?

60-70%
5-13%
10-20%

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What defines an unprovoked VTE? Approximately what percentage of VTEs are considered to be provoked? Does an unprovoked VTE necessitate cancer investigations?

No provoking factors are present
50%
No

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What are some provoking factors for VTE?

Surgery/trauma
Significant immobility (bedbound)
Pregnancy
Combined HRT or pill

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What action should be taken if VTE tests cannot be performed within 4 hours?

Anticoagulate

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Are elasticated compression stockings recommended for therapeutic management of VTE?

Not recommended

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Which type of heparin has an immediate effect? Why do LMWHs have more of a predictable response than unfractionated heparin?

UFH
Longer half-life

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What type of half life has Warfarin? 

Intermediate half life

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Within what timeframe should thrombolysis be administered from symptom onset?

Within 12 hours

What calf pressure should graduated compression stockings provide for mechanical prophylaxis? When should graduated compression stockings be worn?

14-15mmHg All day until patient is mobile

In what conditions should graduated compression stockings NOT be offered?

- Acute stroke - Peripheral artery disease - Peripheral neuropathy - Severe leg oedema - Gangrene - Dermatitis

In what situations should intermittent pneumatic compression be offered to patients?

Pharmacological prophylaxis is contraindicated

What type of analysis should be performed when considering pharmacological prophylaxis?

Risk vs benefit with significant bleeding risk

In what types of patients should intermittent pneumatic compression be offered?

- Lower limb amputation - Fragility fractures of pelvis, hip or proximal femur - Major trauma - Undergoing cranial, abdominal, ENT and spinal surgery

When is unfractionated heparin preferable over LMWHs? What happens if anticoagulation is stopped before 3 months?

In patients with renal impairment Increases risk of further VTE

How long should anticoagulation be given post surgery? How long can anticoagulation be extended to after major cancer surgery in the abdomen? How long can anticoagulation be extended to after spinal surgery?

At least 7 days or until mobilising 28 days 30 days

What could unprovoked VTE be the first presentation of?

Occult cancer

What types of cancer are associated with unprovoked VTE? What type of baseline bloods should be reviewed as further management?

Urogenital, breast, colorectal and lung cancers FBC, renal function, LFTs, PT, APPT

What should be offered to high risk patients before journeys over 3 hours?

Below knee compression hosiery

How much higher is the risk of VTE in pregnant women compared to non-pregnant women? Why are the majority of DVTs left sided in pregnant women?

4x higher Uterine compression of the left iliac vein

How do D-dimer levels change during pregnancy? When are women having IVF at an increased risk of VTE?

Naturally rise Throughout pregnancy

What should be considered for pregnant women during hospital admission? How long should thromboprophylaxis be continued for after a miscarriage or termination of pregnancy? When should thromboprophylaxis be started after a miscarriage or termination of pregnancy?

LMWH during hospital admission Minimum of 7 days 4-8 hours after the event

How long should LMWH be continued for in pregnant women?

Until discharge from hospital

What action should be taken for pregnant women with suspected DVT/PE?

Referral to hospital

What symptoms are associated with increased risk of pelvic DVT?

Lower abdominal/pelvic pain, back or button pain

When is routine peak anti-Xa activity recommended for women on LMWH? How should women at high risk of haemorrhage or VTE at term be managed?

At extremes of body weight (<50kg or >90kg) UFH

What additional treatment should be applied to the affected leg to manage symptoms?

Elasticated graduated compression stocking

When should VTE risk assessment be performed in hospital?

All patients including discharge Within 24 hours using a validated tool

What symptoms might you observe in someone experiencing a PE or DVT?

Swelling Leg pain SOB Chest pain Tenderness

A 58-year old man with cancer and leg swelling visits your pharmacy and is requesting for painkillers. What is the most appropriate intervention?

Refer for urgent medical assessment

What is the first line treatment for patients with a confirmed proximal DVT or PE? What about at risk patients (prophylaxis)?

Apixaban or rivaroxaban LMWH or fondaparinux sodium for 7 days

A patient is diagnosed with a PE and has a creatinine clearance of 23ml/min requires enoxaparin treatment. The patient weighs 78kg. What is the most appropriate dosage form of enoxaparin to prescribe.

1 x 78 = 78mg - renal impairment is 1mg instead of 1.5mg Clexane 80mg/0.8ml pre-filled injection

When should and what thrombophylaxis be offered with elective knee replacement?

Aspirin 14 days or LMWH 14 days with anti-embolism stockings until discharge or rivaroxaban

When should graduated compression not be offered?

- Acute stroke - Peripheral artery disease - Peripheral neuropathy - Severe leg oedema - Gangrene - Dermatitis

When is CHADVASc and ORBIT used?

1. Stroke risk in AF patients ONLY 2. All bleeding risk patients

What thrombophylaxis should used for elective hip replacement and duration?

Either LMWH 10 days followed by aspirin low dose for 28 days or LMWH for 28 days with anti-embolism stockings or rivaroxaban

What should be provided if pregnant women are immobilised or of reduced mobility?

Mechanical prophylaxis - pneumatic compression (cuffs that fill with air and squeeze legs) 1st Then anti-embolism stocking as an alternative

What are the ethical considerations with heparin treatment?

Heparin is of animal origin so may conflict with patient beliefs

Which oral antiplatelet is sometimes considered for extended VTE prophylaxis but is less effective than DOACs?

Aspirin

Which LMWH is commonly used for VTE prophylaxis in general and orthopaedic surgery?

Dalteparin

A 45-year-old man undergoes elective knee replacement surgery. He has no significant renal impairment and needs post-operative VTE prophylaxis. Which is the most suitable option?

Apixaban

A 32 year old pregnant woman 28 weeks gestation is admitted with reduced mobility and a Hx of previous DVT. She has no renal impairment. What is the best choice for VTE prophylaxis?

Enoxaparin (LMWH does not cross placenta)

An 82 year old is admitted with an acute stroke. She is immobile and at a high risk of falls. She has a Hx of AF on warfarin and a recent GI bleed. What is the most appropriate VTE prophylaxis?

Initiate intermittent pneumatic compression