Venous Thromboembolism in Over 16s: Reducing the Risk of Hospital-acquired Deep Vein Thrombosis in Cardiac Care

This specialist Guidelines summary covers assessing and reducing the risk of venous thromboembolism (VTE or blood clots, including deep vein thrombosis and pulmonary embolism) in people aged 16 and over in hospital. It aims to help healthcare professionals to identify people most at risk, and describes interventions that can be used to reduce the risk of VTE.

For guidance on pharmacological VTE prophylaxis for people with COVID-19 pneumonia who are being treated in a hospital or community setting, see the NICE COVID-19 rapid guideline on managing COVID-19.

This summary includes recommendations on:

• risk assessment
• giving information and planning for discharge
• all patients
• interventions for people with:
  • acute coronary syndromes, or acute stroke, or for acutely ill patients
  • renal impairment
  • major trauma
• interventions for people:
  • having palliative care
  • admitted to critical care
  • having cardiac or vascular surgery
• interventions when using anaesthesia.

This summary is intended for use in a secondary care setting by cardiologists. A summary for oncologists in secondary care is also available. For the complete set of recommendations, please refer to the full guideline.

Risk Assessment

All Patients

• Assess all patients to identify the risk of venous thromboembolism (VTE) and bleeding (see the recommendations for All medical patients, for All surgical patients, for All people admitted to the critical care unit). 

People Admitted to Hospital

Medical Patients

• Assess all medical patients to identify the risk of VTE and bleeding:
  • as soon as possible after admission to hospital or by the time of the first consultant review
  • using a tool published by a national UK body, professional network or peer-reviewed journal.

A tool commonly used to develop a treatment plan for medical patients is the Department of Health VTE risk assessment tool.

• Balance the person's individual risk of VTE against their risk of bleeding when deciding whether to offer pharmacological thromboprophylaxis to medical patients
• If using pharmacological VTE prophylaxis for medical patients, start it as soon as possible and within 14 hours of admission, unless otherwise stated in the population-specific recommendations (see the sections on Interventions for people with acute coronary syndromes or acute stroke or for acutely ill patients, Interventions for people with renal impairment, Interventions for people with cancer, Interventions for people having palliative care, Interventions for people admitted to critical care). 

Surgical and Trauma Patients

• Assess all surgical and trauma patients to identify the risk of VTE and bleeding:
  • as soon as possible after admission to hospital or by the time of the first consultant review
  • using a tool published by a national UK body, professional network or peer-reviewed journal.

A tool commonly used to develop a treatment plan for surgical patients is the Department of Health VTE risk assessment tool.

• Balance the person's individual risk of VTE against their risk of bleeding when deciding whether to offer pharmacological thromboprophylaxis to surgical and trauma patients
• If using pharmacological VTE prophylaxis for surgical and trauma patients, start it as soon as possible and within 14 hours of admission, unless otherwise stated in the population-specific recommendations (see the sections on Interventions when using anaesthesia, Interventions for people with major trauma, and Interventions for people having cardiac or vascular surgery). 

Reassessment of Risk of VTE and Bleeding

• Reassess all medical, surgical and trauma patients for risk of VTE and bleeding at the point of consultant review or if their clinical condition changes. 

Giving Information and Planning for Discharge

• On admission, ensure that people understand the reason for having a risk assessment for VTE and bleeding
• For people admitted to hospital who are at increased risk of VTE, give them and their family members or carers (as appropriate) verbal and written information on the following before offering VTE prophylaxis:
  • the person's risks and possible consequences of VTE
  • the importance of VTE prophylaxis and its possible side effects – for example, pharmacological prophylaxis can increase bleeding risk
  • the correct use of VTE prophylaxis – for example, anti-embolism stockings, intermittent pneumatic compression
  • how people can reduce their risk of VTE (such as keeping well hydrated and, if possible, exercising and becoming more mobile)
• Be aware that heparins are of animal origin and this may be of concern to some people (See Religion or belief: a practical guide for the NHS). Discuss the alternatives with people who have concerns about using animal products, after discussing their suitability, advantages and disadvantages with the person
• As part of the discharge plan, give patients and their family members or carers (as appropriate) verbal and written information on:
  • the signs and symptoms of deep vein thrombosis (DVT) and pulmonary embolism
  • how people can reduce their risk of VTE (such as keeping well hydrated and, if possible, exercising and becoming more mobile)
  • the importance of seeking help if DVT, pulmonary embolism or other adverse events are suspected 
• Give people discharged with VTE prophylaxis and their family members or carers (as appropriate) verbal and written information on:
  • the importance of using VTE prophylaxis correctly (including the correct administration and disposal of pharmacological prophylaxis)
  • the importance of continuing treatment for the recommended duration
  • the signs and symptoms of adverse events related to VTE prophylaxis
  • the importance of seeking help and who to contact if people have problems using VTE prophylaxis
• Ensure that people who are discharged with anti-embolism stockings:
  • understand the benefits of wearing them
  • understand the importance of wearing them correctly
  • understand the need to remove them daily for hygiene purposes
  • are able to remove and replace them, or have someone available who will be able to do this for them
  • know what to look for if there is a problem – for example, skin marking, blistering or discolouration, particularly over the heels and bony prominences
  • know who to contact if there is a problem
  • know when to stop wearing them
• Ensure that people who are discharged with pharmacological and/or mechanical VTE prophylaxis are able to use it correctly, or have arrangements made for someone to be available who will be able to help them 
• Notify the person's GP if the person has been discharged with pharmacological and/or mechanical VTE prophylaxis to be used at home. 

All Patients

Mechanical Prophylaxis

• Do not offer anti-embolism stockings to people who have:
  • suspected or proven peripheral arterial disease
  • peripheral arterial bypass grafting
  • peripheral neuropathy or other causes of sensory impairment
  • any local conditions in which anti-embolism stockings may cause damage – for example, fragile 'tissue paper' skin, dermatitis, gangrene or recent skin graft
  • known allergy to material of manufacture
  • severe leg oedema
  • major limb deformity or unusual leg size or shape preventing correct fit.

Use caution and clinical judgement when applying anti-embolism stockings over venous ulcers or wounds.

• Ensure that people who need anti-embolism stockings have their legs measured and that they are provided with the correct size of stocking. Anti-embolism stockings should be fitted and patients shown how to use them by staff trained in their use
• Ensure that people who develop oedema or postoperative swelling have their legs re‑measured and anti-embolism stockings refitted
• If arterial disease is suspected, seek expert opinion before fitting anti-embolism stockings 
• Use anti-embolism stockings that provide graduated compression and produce a calf pressure of 14 mmHg to 15 mmHg. (This relates to a pressure of 14 mmHg to 18 mmHg at the ankle and is in line with the British Standard Institution's BS 661210:2018 Specification for graduated compression hosiery, anti-embolism hosiery and graduated support hosiery) 
• Encourage people to wear their anti-embolism stockings day and night until they no longer have significantly reduced mobility
• Remove anti-embolism stockings daily for hygiene purposes and to inspect skin condition. In people with a significant reduction in mobility, poor skin integrity or any sensory loss, inspect the skin 2 or 3 times a day, particularly over the heels and bony prominences
• Monitor the use of anti-embolism stockings and offer assistance if they are not being worn correctly. 
• Stop the use of anti-embolism stockings if there is marking, blistering or discolouration of the skin, particularly over the heels and bony prominences, or if the person experiences pain or discomfort. If suitable, offer intermittent pneumatic compression as an alternative
• Do not offer intermittent pneumatic compression to people with a known allergy to the material of manufacture
• Advise the person to wear their device for as much time as possible. 

Pharmacological Prophylaxis

• For pharmacological VTE prophylaxis in people under 18, follow the recommendations on apixaban, aspirin, dabigatran etexilate, fondaparinux sodium, low-molecular-weight heparin (LMWH) and rivaroxaban in this guideline.

In March 2018, the use of these drugs in young people under 18 was off label. See NICE's information on prescribing medicines.

All Surgery

• Advise people to consider stopping oestrogen-containing oral contraceptives or hormone replacement therapy 4 weeks before elective surgery. If stopped, provide advice on alternative contraceptive methods. 

Nursing Care: Early Mobilisation and Hydration

• Encourage people to mobilise as soon as possible
• Do not allow people to become dehydrated unless clinically indicated. 

People Using Antiplatelet Agents

• Consider VTE prophylaxis for people who are having antiplatelet agents for other conditions and whose risk of VTE outweighs their risk of bleeding. Take into account the risk of bleeding and of comorbidities such as arterial thrombosis
  • If the risk of VTE outweighs the risk of bleeding, consider pharmacological VTE prophylaxis based on their condition or procedure
  • If the risk of bleeding outweighs the risk of VTE, consider mechanical VTE prophylaxis. 

People Using Anticoagulation Therapy

• Consider VTE prophylaxis for people at increased risk of VTE who are interrupting anticoagulant therapy. 

Interventions for People with Acute Coronary Syndromes or Acute Stroke or for Acutely Ill Patients

Acute Coronary Syndromes

• Be aware that people receiving anticoagulant drugs as part of their treatment for an acute coronary syndrome do not usually need VTE prophylaxis. See also the recommendation in the section on People using anticoagulation therapy. 

Acute Stroke Patients

• Do not offer anti-embolism stockings for VTE prophylaxis to people who are admitted for acute stroke 
• Consider intermittent pneumatic compression for VTE prophylaxis for people who are immobile and admitted with acute stroke. If using, start it within 3 days of acute stroke
• Explain to the person admitted with acute stroke and their family members or carers (as appropriate) that intermittent pneumatic compression:
  • reduces the risk of DVT and may increase their chances of survival
  • will not help them recover from stroke, and there may be an associated increased risk of surviving with severe disability
• When using intermittent pneumatic compression for people who are admitted with acute stroke, provide it for 30 days or until the person is mobile or discharged, whichever is sooner. 

Acutely Ill Medical Patients

For guidance on pharmacological VTE prophylaxis for people with COVID-19 pneumonia who are being treated in a hospital or community setting, see our COVID-19 rapid guideline on managing COVID-19.

• Offer pharmacological VTE prophylaxis for a minimum of 7 days to acutely ill medical patients whose risk of VTE outweighs their risk of bleeding:
  • use LMWH as first-line treatment
  • if LMWH is contraindicated, use fondaparinux sodium. 

In March 2018, the use of LMWH and fondaparinux sodium in young people under 18 was off label. See NICE's information on prescribing medicines.

Interventions for People with Renal Impairment

In March 2018, the use of LMWH in young people under 18 was off label. See NICE's information on prescribing medicines.

• If using pharmacological VTE prophylaxis for people with renal impairment, choose either LMWH or unfractionated heparin (UFH)
• If needed, reduce the dose of LMWH and UFH for people with renal impairment. Base the decision on multidisciplinary or senior opinion, or locally agreed protocols. 

Interventions for People having Palliative Care

• Consider pharmacological VTE prophylaxis for people who are having palliative care. Take into account temporary increases in thrombotic risk factors, risk of bleeding, likely life expectancy and the views of the person and their family members or carers (as appropriate):
  • Use LMWH as first-line treatment
  • If LMWH is contraindicated, use fondaparinux sodium. 

In March 2018, the use of LMWH and fondaparinux sodium in young people under 18 was off label. See NICE's information on prescribing medicines.

• Do not offer VTE prophylaxis to people in the last days of life
• For recommendations on shared decision-making in the last days of life, see the NICE guideline on care of dying adults in the last days of life
• Review VTE prophylaxis daily for people who are having palliative care, taking into account the views of the person, their family members or carers (as appropriate) and the multidisciplinary team. 

Interventions for People Admitted to Critical Care

For guidance on pharmacological VTE prophylaxis for people with COVID-19 pneumonia who are being treated in a hospital or community setting, see our COVID-19 rapid guideline on managing COVID-19.

• Assess all people admitted to the critical care unit for risk of VTE and bleeding 
• Provide LMWH to people admitted to the critical care unit if pharmacological VTE prophylaxis is not contraindicated. For people with renal impairment, see the recommendations on interventions for people with renal impairment 
  • in March 2018, the use of LMWH in young people under 18 was off label. See NICE's information on prescribing medicines
• Consider mechanical VTE prophylaxis for people admitted to the critical care unit if pharmacological prophylaxis is contraindicated based on their condition or procedure
• If using mechanical VTE prophylaxis for people admitted to the critical care unit, start it on admission and continue until the person no longer has reduced mobility relative to their normal or anticipated mobility 
• Reassess VTE and bleeding risk daily for people in critical care units
• Assess VTE and bleeding risk more than once a day in people admitted to the critical care unit if the person's condition is changing rapidly. 

Interventions When Using Anaesthesia

• Consider regional anaesthesia for individual patients, in addition to other methods of VTE prophylaxis, as it carries a lower risk of VTE than general anaesthesia. Take into account the person's preferences, their suitability for regional anaesthesia and any other planned method of VTE prophylaxis 
• If regional anaesthesia is used, plan the timing of pharmacological VTE prophylaxis to minimise the risk of epidural haematoma. If antiplatelet or anticoagulant agents are being used, or their use is planned, refer to the summary of product characteristics for guidance about the safety and timing of these in relation to the use of regional anaesthesia 
• Do not routinely offer pharmacological or mechanical VTE prophylaxis to people undergoing a surgical procedure with local anaesthesia by local infiltration with no limitation of mobility. 

Interventions for People with Major Trauma

• Offer mechanical VTE prophylaxis with intermittent pneumatic compression on admission to people with serious or major trauma. Continue until the person no longer has significantly reduced mobility relative to their normal or anticipated mobility
• Reassess risk of VTE and bleeding in people with serious or major trauma whenever their clinical condition changes and at least daily
• Consider pharmacological VTE prophylaxis for people with serious or major trauma as soon as possible after the risk assessment when the risk of VTE outweighs the risk of bleeding. Continue for a minimum of 7 days. 

Interventions for People having Cardiac or Vascular Surgery

Cardiac Surgery

• Consider mechanical VTE prophylaxis on admission for people who are undergoing cardiac surgery who are at increased risk of VTE. Choose either:
  • anti-embolism stockings or
  • intermittent pneumatic compression.

Continue until the person no longer has significantly reduced mobility relative to their normal or anticipated mobility.

• Consider adding pharmacological VTE prophylaxis for a minimum of 7 days for people who are undergoing cardiac surgery and are not having other anticoagulation therapy:
  • Use LMWH as first-line treatment
  • If LMWH is contraindicated, use fondaparinux sodium.

In March 2018, the use of LMWH and fondaparinux sodium in young people under 18 was off label. See NICE's information on prescribing medicines.

Vascular Surgery

Open Vascular Surgery or Endovascular Aneurysm Repair

• Consider pharmacological VTE prophylaxis with LMWH for a minimum of 7 days for people who are undergoing open vascular surgery or major endovascular procedures, including endovascular aneurysm repair whose risk of VTE outweighs their risk of bleeding. 

In March 2018, the use of LMWH in young people under 18 was off label. See NICE's information on prescribing medicines.

• Consider mechanical VTE prophylaxis on admission for people who are undergoing open vascular surgery or major endovascular procedures, including endovascular aneurysm repair, if pharmacological prophylaxis is contraindicated. Choose either:
  • anti-embolism stockings or
  • intermittent pneumatic compression
    • continue until the person no longer has significantly reduced mobility relative to their normal or anticipated mobility. 

Lower Limb Amputation

• Consider pharmacological VTE prophylaxis with LMWH for a minimum of 7 days for people who are undergoing lower limb amputation whose risk of VTE outweighs their risk of bleeding. 

In March 2018, the use of LMWH in young people under 18 was off label. See NICE's information on prescribing medicines.

• Consider mechanical VTE prophylaxis with intermittent pneumatic compression on the contralateral leg, on admission, for people who are undergoing lower limb amputation and if pharmacological prophylaxis is contraindicated 
• For people undergoing lower limb amputation, continue mechanical VTE prophylaxis until the person no longer has significantly reduced mobility relative to their anticipated mobility. 

Varicose Vein Surgery

• Be aware that VTE prophylaxis is generally not needed for people undergoing varicose vein surgery where:
  • total anaesthesia time is less than 90 minutes and
  • the person is at low risk of VTE
• Consider pharmacological VTE prophylaxis with LMWH, starting 6 to 12 hours after surgery and continuing for 7 days for people undergoing varicose vein surgery if:
  • total anaesthesia time is more than 90 minutes or
  • the person's risk of VTE outweighs their risk of bleeding. 

In March 2018, the use of LMWH in young people under 18 was off label. See NICE's information on prescribing medicines.

• Consider mechanical VTE prophylaxis with anti-embolism stockings, on admission, for people undergoing varicose vein surgery:
  • who are at increased risk of VTE and
  • if pharmacological prophylaxis is contraindicated 
  • If using anti-embolism stockings for people undergoing varicose vein surgery, continue until the person no longer has significantly reduced mobility relative to their normal or anticipated mobility 
• If using anti-embolism stockings for people undergoing varicose vein surgery, continue until the person no longer has significantly reduced mobility relative to their normal or anticipated mobility.