Guidance

Recommendations

Recommendations

People have the right to be involved in discussions and make informed decisions about their care, as described in NICE's information on making decisions about your care.

Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off-label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding.

1.1 Diagnosis and initial management

NICE has produced a visual summary of the recommendations on diagnosis and initial management of suspected deep vein thrombosis (DVT) and pulmonary embolism (PE).

Signs or symptoms of DVT

1.1.1

For people who present with signs or symptoms of DVT, such as a swollen or painful leg, assess their general medical history and do a physical examination to exclude other causes. [2012]

1.1.2

If DVT is suspected, use the 2‑level DVT Wells score (table 1) to estimate the clinical probability of DVT. [2012]

Table 1 Two-level DVT Wells score
Clinical feature Points

Active cancer (treatment ongoing, within 6 months, or palliative)

1

Paralysis, paresis or recent plaster immobilisation of the lower extremities

1

Recently bedridden for 3 days or more, or major surgery within 12 weeks requiring general or regional anaesthesia

1

Localised tenderness along the distribution of the deep venous system

1

Entire leg swollen

1

Calf swelling at least 3 cm larger than asymptomatic side

1

Pitting oedema confined to the symptomatic leg

1

Collateral superficial veins (non-varicose)

1

Previously documented DVT

1

An alternative diagnosis is at least as likely as DVT

-2
Clinical probability simplified score Points

DVT likely

2 points or more

DVT unlikely

1 point or less

Adapted with permission from Wells et al. (2003) Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis.

DVT likely (Wells score 2 points or more)
1.1.3

Offer people with a likely DVT Wells score (2 points or more):

  • a proximal leg vein ultrasound scan, with the result available within 4 hours if possible (if the scan result cannot be obtained within 4 hours follow recommendation 1.1.4)

  • a D‑dimer test if the scan result is negative. [2012]

1.1.4

If a proximal leg vein ultrasound scan result cannot be obtained within 4 hours, offer people with a DVT Wells score of 2 points or more:

1.1.6

For people with a negative proximal leg vein ultrasound scan and a positive D‑dimer test result:

  • stop interim therapeutic anticoagulation, but do not stop:

  • offer a repeat proximal leg vein ultrasound scan 6 to 8 days later and

    • if the repeat scan result is positive, follow the actions in recommendation 1.1.5 [2012, amended 2020]

    • if the repeat scan result is negative, follow the actions in recommendation 1.1.7. [2012, amended 2020]

1.1.7

For people with a negative proximal leg vein ultrasound scan and a negative D‑dimer test result:

  • stop interim therapeutic anticoagulation, but do not stop:

  • think about alternative diagnoses [2012, amended 2020]

  • tell the person that it is not likely they have DVT. Discuss with them the signs and symptoms of DVT and when and where to seek further medical help. [2012, amended 2020]

DVT unlikely (Wells score 1 point or less)
1.1.9

If the D‑dimer test result is negative, follow the actions in recommendation 1.1.7. [2012]

1.1.10

If the D‑dimer test result is positive, offer:

1.1.11

If the proximal leg vein ultrasound scan is:

  • positive, follow the actions in recommendation 1.1.5 [2012]

  • negative, follow the actions in recommendation 1.1.7, that is:

    • stop interim therapeutic anticoagulation, but do not stop:

    • think about alternative diagnoses [2012]

    • tell the person that it is not likely they have DVT. Discuss with them the signs and symptoms of DVT and when and where to seek further medical help. [2012]

For a short explanation of why the committee made the 2023 recommendations and how they might affect practice, see the rationale and impact section on diagnosis and initial management in people with COVID-19.

Full details of the evidence and the committee's discussion are in evidence review I: diagnosing VTE in people with COVID-19.

D‑dimer testing
1.1.12

When offering D‑dimer testing for suspected DVT or PE, consider a point‑of‑care test if laboratory facilities are not immediately available. [2020]

1.1.13

If using a point-of-care D‑dimer test, choose a fully quantitative test. [2020]

1.1.14

When using a point-of-care or laboratory D‑dimer test, consider an age‑adjusted D‑dimer test threshold for people aged over 50. [2020]

For a short explanation of why the committee made the 2020 recommendations and how they might affect practice, see the rationale and impact section on D-dimer testing.

Full details of the evidence and the committee's discussion are in evidence review A: D-dimer testing in the diagnosis of deep vein thrombosis and pulmonary embolism.

Signs or symptoms of PE

1.1.15

For people who present with signs or symptoms of PE, such as chest pain, shortness of breath or coughing up blood, assess their general medical history, do a physical examination and offer a chest X‑ray to exclude other causes. [2012]

Pulmonary embolism rule-out criteria (the PERC rule)
1.1.16

If clinical suspicion of PE is low based on the overall clinical impression (from general medical history, physical examination and any initial investigations such as electrocardiography or chest X-ray), and other diagnoses are feasible, consider using the pulmonary embolism rule-out criteria (PERC) to help determine whether any further investigations for PE are needed.

Be aware that the PERC rule has not been validated in people with COVID‑19. [2020, amended 2023]

For a short explanation of why the committee made the 2020 recommendation and amended the recommendation in 2023 and how it might affect practice, see the rationale and impact section on the PERC rule.

Full details of the evidence and the committee's discussion are in evidence review B: the use of the pulmonary embolism rule-out criteria for diagnosis of pulmonary embolism and supporting document: refresh of recommendation 1.1.16 on the PERC rule.

1.1.17

If PE is suspected, use the 2‑level PE Wells score (table 2) to estimate the clinical probability of PE. [2012]

Table 2 Two-level PE Wells score
Clinical feature Points

Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins)

3

An alternative diagnosis is less likely than PE

3

Heart rate more than 100 beats per minute

1.5

Immobilisation for more than 3 days or surgery in the previous 4 weeks

1.5

Previous DVT/PE

1.5

Haemoptysis

1

Malignancy (on treatment, treated in the last 6 months, or palliative)

1
Clinical probability simplified score Points

PE likely

More than 4 points

PE unlikely

4 points or less

Adapted with permission from Wells et al. (2000) Derivation of a simple clinical model to categorize patients' probability of pulmonary embolism: increasing the model's utility with the SimpliRED D-dimer.

PE likely (Wells score more than 4 points)
1.1.18

For people with a likely PE Wells score (more than 4 points):

  • offer a computed tomography pulmonary angiogram (CTPA) immediately if possible or

  • for people with an allergy to contrast media, severe renal impairment (estimated creatinine clearance less than 30 ml/min) or a high risk from irradiation, assess the suitability of a ventilation/perfusion single photon emission computed tomography (V/Q SPECT) scan or, if a V/Q SPECT scan is not available, a V/Q planar scan, as an alternative to CTPA.

    If a CTPA, V/Q SPECT or V/Q planar scan cannot be done immediately, offer interim therapeutic anticoagulation (see the section on interim therapeutic anticoagulation for suspected DVT or PE). [2012, amended 2020]

1.1.20

If PE is not identified by CTPA, V/Q SPECT or V/Q planar scan:

  • consider a proximal leg vein ultrasound scan if DVT is suspected [2012, amended 2020]

  • if DVT is not suspected:

    • stop interim therapeutic anticoagulation, but do not stop:

    • think about alternative diagnoses [2012, amended 2020]

    • tell the person that it is not likely they have PE. Discuss with them the signs and symptoms of PE and when and where to seek further medical help. [2012, amended 2020]

PE unlikely (Wells score 4 points or less)
1.1.21

Offer people with an unlikely PE Wells score (4 points or less):

  • a D‑dimer test with the result available within 4 hours if possible (see the section on D-dimer testing) [2012, amended 2020] or

  • if the D‑dimer test result cannot be obtained within 4 hours (in any setting), offer interim therapeutic anticoagulation while awaiting the result (see the section on interim therapeutic anticoagulation for suspected DVT or PE). [2012, amended 2020]

    If the D‑dimer test result is:

  • positive, follow the actions in recommendations 1.1.18 and 1.1.19 [2012, amended 2020]

  • negative:

    • stop interim therapeutic anticoagulation, but do not stop:

    • think about alternative diagnoses [2012, amended 2020]

    • tell the person that it is not likely they have PE. Discuss with them the signs and symptoms of PE and when and where to seek further medical help. [2012, amended 2020]

For a short explanation of why the committee made the 2023 recommendations and how they might affect practice, see the rationale and impact section on diagnosis and initial management in people with COVID-19.

Full details of the evidence and the committee's discussion are in evidence review I: diagnosing VTE in people with COVID-19.

Signs or symptoms of both DVT and PE

1.1.22

For people who present with signs or symptoms of both DVT and PE, carry out initial diagnostic investigations for either DVT or PE, basing the choice of diagnostic investigations on clinical judgement. [2012]

1.2 Outpatient treatment for low-risk PE

1.2.1

Consider outpatient treatment for suspected or confirmed low-risk PE, using a validated risk stratification tool to determine the suitability of outpatient treatment. [2020]

1.2.4

Agree a plan for monitoring and follow-up with people having outpatient treatment for suspected or confirmed low-risk PE. Give them:

  • written information on symptoms and signs to look out for, including the potential complications of thrombosis and of treatment

  • direct contact details of a healthcare professional or team with expertise in thrombosis who can discuss any new symptoms or signs, or other concerns

  • information about out-of-hours services they can contact when their healthcare team is not available. [2020]

For a short explanation of why the committee made the 2020 recommendations and how they might affect practice, see the rationale and impact section on outpatient treatment for low-risk PE.

Full details of the evidence and the committee's discussion are in evidence review E: outpatient treatment of low-risk pulmonary embolism.

1.3 Anticoagulation treatment for suspected or confirmed DVT or PE

NICE has produced a visual summary of the recommendations on anticoagulation treatment for DVT or PE.

Interim therapeutic anticoagulation for suspected DVT or PE

1.3.4

When using interim therapeutic anticoagulation for suspected proximal DVT or PE:

  • carry out baseline blood tests including full blood count, renal and hepatic function, prothrombin time (PT) and activated partial thromboplastin time (APTT)

  • do not wait for the results of baseline blood tests before starting anticoagulation treatment

  • review, and if necessary act on, the results of baseline blood tests within 24 hours of starting interim therapeutic anticoagulation. [2020]

Anticoagulation treatment for confirmed DVT or PE

1.3.6

If not already done, carry out baseline blood tests, as outlined in recommendation 1.3.4, when starting anticoagulation treatment. [2020]

1.3.8

Offer either apixaban or rivaroxaban to people with confirmed proximal DVT or PE (but see recommendations 1.3.11 to 1.3.20 for people with any of the clinical features listed in recommendation 1.3.7). If neither apixaban nor rivaroxaban is suitable offer:

  • LMWH for at least 5 days followed by dabigatran or edoxaban or

  • LMWH concurrently with a vitamin K antagonist (VKA) for at least 5 days, or until the international normalised ratio (INR) is at least 2.0 in 2 consecutive readings, followed by a VKA on its own. [2020]

1.3.9

Do not routinely offer unfractionated heparin (UFH) with a VKA to treat confirmed proximal DVT or PE unless the person has renal impairment or established renal failure (see recommendations 1.3.13 and 1.3.14) or an increased risk of bleeding. [2020]

1.3.10

Do not routinely offer self‑management or self‑monitoring of INR to people who have had DVT or PE and are having treatment with a VKA. [2012]

Anticoagulation treatment for DVT or PE in people at extremes of body weight
1.3.11

Consider anticoagulation treatment with regular monitoring of therapeutic levels for people with confirmed proximal DVT or PE who weigh less than 50 kg or more than 120 kg, to ensure effective anticoagulation.

Note the cautions and requirements for dose adjustment and monitoring in the medicine's summary of product characteristics (SPC), and follow locally agreed protocols or advice from a specialist or multidisciplinary team. [2020]

Anticoagulation treatment for PE with haemodynamic instability
1.3.12

For people with confirmed PE and haemodynamic instability, offer continuous UFH infusion and consider thrombolytic therapy (see the section on thrombolytic therapy). [2020]

Anticoagulation treatment for DVT or PE with renal impairment or established renal failure

In March 2020, some LMWHs were off label for the treatment of DVT or PE in people with severe renal impairment (estimated creatinine clearance 15 ml/min to 30 ml/min) or established renal failure (estimated creatinine clearance less than 15 ml/min). See NICE's information on prescribing medicines.

1.3.13

Offer people with confirmed proximal DVT or PE and renal impairment (estimated creatinine clearance between 15 ml/min and 50 ml/min) one of:

  • apixaban

  • rivaroxaban

  • LMWH for at least 5 days followed by:

    • edoxaban or

    • dabigatran if estimated creatinine clearance is 30 ml/min or above

  • LMWH or UFH, given concurrently with a VKA for at least 5 days or until the INR is at least 2.0 in 2 consecutive readings, followed by a VKA on its own.

    Note the cautions and requirements for dose adjustment and monitoring in the medicine's SPC, and follow locally agreed protocols or advice from a specialist or multidisciplinary team. [2020]

1.3.14

Offer people with confirmed proximal DVT or PE and established renal failure (estimated creatinine clearance less than 15 ml/min) one of:

  • LMWH

  • UFH

  • LMWH or UFH concurrently with a VKA for at least 5 days or until the INR is at least 2.0 in 2 consecutive readings, followed by a VKA on its own.

    Note the cautions and requirements for dose adjustment and monitoring in the medicine's SPC, and follow locally agreed protocols or advice from a specialist or multidisciplinary team. [2020]

Anticoagulation treatment for DVT or PE with active cancer

In March 2020, most anticoagulants were off label for the treatment of DVT or PE in people with active cancer. See NICE's information on prescribing medicines.

1.3.16

When choosing anticoagulation treatment for people with active cancer and confirmed proximal DVT or PE, take into account the tumour site, interactions with other drugs including those used to treat cancer, and the person's bleeding risk. [2020]

1.3.17

Consider a direct-acting oral anticoagulant (DOAC) for people with active cancer and confirmed proximal DVT or PE. [2020]

1.3.18

If a DOAC is unsuitable consider LMWH alone or LMWH concurrently with a VKA for at least 5 days, or until the INR is at least 2.0 in 2 consecutive readings, followed by a VKA on its own. [2020]

Anticoagulation treatment for DVT or PE with triple positive antiphospholipid syndrome
1.3.20

Offer people with confirmed proximal DVT or PE and an established diagnosis of triple positive antiphospholipid syndrome LMWH concurrently with a VKA for at least 5 days, or until the INR is at least 2.0 in 2 consecutive readings, followed by a VKA on its own. [2020]

Treatment failure

1.3.21

If anticoagulation treatment fails:

  • check adherence to anticoagulation treatment

  • address other sources of hypercoagulability

  • increase the dose of anticoagulant or change to an anticoagulant with a different mode of action. [2020]

1.4 Long-term anticoagulation for secondary prevention

1.4.2

Consider stopping anticoagulation treatment 3 months (3 to 6 months for people with active cancer) after a provoked DVT or PE if the provoking factor is no longer present and the clinical course has been uncomplicated. If anticoagulation treatment is stopped, give advice about the risk of recurrence and provide:

  • written information on symptoms and signs to look out for

  • direct contact details of a healthcare professional or team with expertise in thrombosis who can discuss any new symptoms or signs, or other concerns

  • information about out-of-hours services they can contact when their healthcare team is not available. [2020]

1.4.3

Consider continuing anticoagulation beyond 3 months (6 months for people with active cancer) after an unprovoked DVT or PE. Base the decision on the balance between the person's risk of VTE recurrence and their risk of bleeding. Discuss the risks and benefits of long-term anticoagulation with the person, and take their preferences into account. [2020]

1.4.4

Explain to people with unprovoked DVT or PE and a low bleeding risk that the benefits of continuing anticoagulation treatment are likely to outweigh the risks. [2020]

1.4.5

Do not rely solely on predictive risk tools to assess the need for long-term anticoagulation treatment. [2020]

1.4.6

Consider using the HAS-BLED score for major bleeding risk to assess the risk of major bleeding in people having anticoagulation treatment for unprovoked proximal DVT or PE. Discuss stopping anticoagulation if the HAS-BLED score is 4 or more and cannot be modified. [2020]

1.4.7

Take into account the person's preferences and their clinical situation when selecting an anticoagulant for long-term treatment. [2020]

1.4.8

For people who do not have renal impairment, active cancer, established triple positive antiphospholipid syndrome or extreme body weight (less than 50 kg or more than 120 kg):

  • offer continued treatment with the current anticoagulant if it is well tolerated or

  • if the current treatment is not well tolerated, or the clinical situation or person's preferences have changed, consider switching to apixaban if the current treatment is a direct-acting anticoagulant other than apixaban. [2020]

1.4.9

For people with renal impairment, active cancer, established triple positive antiphospholipid syndrome or extreme body weight (less than 50 kg or more than 120 kg), consider carrying on with the current treatment if it is well tolerated. [2020]

1.4.11

For people who decline continued anticoagulation treatment, consider aspirin 75 mg or 150 mg daily.

In March 2020, the use of aspirin for secondary prevention of DVT or PE was off label. See NICE's information on prescribing medicines. [2020]

1.4.12

Review general health, risk of VTE recurrence, bleeding risk and treatment preferences at least once a year for people taking long-term anticoagulation treatment or aspirin. [2020]

For a short explanation of why the committee made the 2020 recommendations on reviewing anticoagulation treatment and how they might affect practice, see the rationale and impact section on long-term anticoagulation for secondary prevention.

Full details of the evidence and the committee's discussion are in:

Evidence review G: economic modelling report for pharmacological treatment also underpins recommendation 1.4.8.

1.5 Information and support for people having anticoagulation treatment

1.5.1

Give people having anticoagulation treatment verbal and written information about:

  • how to use anticoagulants

  • how long to take anticoagulants

  • possible side effects of anticoagulants and what to do if these occur

  • how other medications, foods and alcohol can affect oral anticoagulation treatment

  • any monitoring needed for their anticoagulant treatment

  • how anticoagulants may affect their dental treatment

  • taking anticoagulants if they are planning pregnancy or become pregnant

  • how anticoagulants may affect activities such as sports and travel

  • when and how to seek medical help. [2012]

1.5.2

Give people who are having anticoagulation treatment information and an 'anticoagulant alert card' that is specific to their treatment. Advise them to carry the 'anticoagulant alert card' at all times. [2012]

1.6 Thrombolytic therapy

DVT

PE

1.7 Mechanical interventions

Inferior vena caval filters

1.7.1

Do not offer an inferior vena caval (IVC) filter to people with proximal DVT or PE unless:

  • it is part of a prospective clinical study or

  • anticoagulation is contraindicated or a PE has occurred during anticoagulation treatment (see recommendations 1.7.2 and 1.7.3). [2020]

1.7.2

Consider an IVC filter for people with proximal DVT or PE when anticoagulation treatment is contraindicated. Remove the IVC filter when anticoagulation treatment is no longer contraindicated and has been established. [2020]

1.7.3

Consider an IVC filter for people with proximal DVT or PE who have a PE while taking anticoagulation treatment only after taking the steps outlined in the recommendation on treatment failure. [2020]

1.7.4

Before fitting an IVC filter, ensure that there is a strategy in place for it to be removed at the earliest possible opportunity. Document the strategy and review it if the clinical situation changes. [2020]

For a short explanation of why the committee made the 2020 recommendations and how they might affect practice, see the rationale and impact section on IVC filters.

Full details of the evidence and the committee's discussion are in evidence review H: inferior vena caval filters for people with venous thromboembolism.

Elastic graduated compression stockings

1.7.5

Do not offer elastic graduated compression stockings to prevent post-thrombotic syndrome or VTE recurrence after a DVT. This recommendation does not cover the use of elastic stockings for the management of leg symptoms after DVT. [2015]

1.7.6

If offering elastic graduated compression stockings to manage leg symptoms after DVT, explain how to apply and use them, how long they should be worn and when they should be replaced. [2012]

1.8 Investigations for cancer

1.8.1

For people with unprovoked DVT or PE who are not known to have cancer, review the medical history and baseline blood test results including full blood count, renal and hepatic function, PT and APTT, and offer a physical examination. [2020]

1.8.2

Do not offer further investigations for cancer to people with unprovoked DVT or PE unless they have relevant clinical symptoms or signs (for further information, see the NICE guideline on suspected cancer). [2020]

For a short explanation of why the committee made the 2020 recommendations and how they might affect practice, see the rationale and impact section on investigations for cancer.

Full details of the evidence and the committee's discussion are in evidence review C: investigations for cancer in people with unprovoked venous thromboembolism.

1.9 Thrombophilia testing

1.9.1

Do not offer testing for hereditary thrombophilia to people who are continuing anticoagulation treatment. [2012, amended 2020]

1.9.2

Do not offer thrombophilia testing to people who have had provoked DVT or PE. [2012]

1.9.3

Consider testing for antiphospholipid antibodies in people who have had unprovoked DVT or PE if it is planned to stop anticoagulation treatment, but be aware that these tests can be affected by anticoagulants and specialist advice may be needed. [2012, amended 2020]

1.9.4

Consider testing for hereditary thrombophilia in people who have had unprovoked DVT or PE and who have a first‑degree relative who has had DVT or PE if it is planned to stop anticoagulation treatment, but be aware that these tests can be affected by anticoagulants and specialist advice may be needed. [2012, amended 2020]

1.9.5

Do not routinely offer thrombophilia testing to first‑degree relatives of people with a history of DVT or PE and thrombophilia. [2012]

Terms used in this guideline

Active cancer

Receiving active antimitotic treatment; or diagnosed within the past 6 months; or recurrent or metastatic; or inoperable. Excludes squamous skin cancer and basal cell carcinoma.

Estimated creatinine clearance

Creatinine clearance estimated using the Cockcroft and Gault formula; see the BNF's information on prescribing in renal impairment.

Provoked DVT or PE

DVT or PE in a person with a recent (within 3 months) and transient major clinical risk factor for VTE, such as surgery, trauma, significant immobility (bedbound, unable to walk unaided or likely to spend a substantial proportion of the day in bed or in a chair), pregnancy or puerperium – or in a person who is having hormonal therapy (combined oral contraceptive pill or hormone replacement therapy).

Proximal DVT

DVT at or above the level of the popliteal trifurcation area.

Unprovoked DVT or PE

DVT or PE in a person with no recent major clinical risk factor for VTE (see provoked DVT or PE) who is not having hormonal therapy (combined oral contraceptive pill or hormone replacement therapy).

Wells score

Clinical prediction rule for estimating the probability of DVT or PE. There are a number of versions of Wells scores available. This guideline recommends the 2‑level DVT Wells score and the 2-level PE Wells score.