Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

non-pregnant: no cancer and with an acute medical illness

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low molecular weight heparin, fondaparinux, or unfractionated heparin

Thromboprophylaxis should be considered for all patients judged to be at risk for venous thromboembolism (VTE) when admitted to hospital with an acute or critical medical illness (impairing mobility).[105][112]

Anticoagulant thromboprophylaxis with a low molecular weight heparin (LMWH) such as enoxaparin or dalteparin, low-dose unfractionated heparin (UFH), or fondaparinux is recommended for acutely ill hospitalised medical patients at increased risk of VTE, but without excessive bleeding risk.[105] LMWH has better pharmacokinetic properties than UFH and is associated with a lower incidence of postoperative heparin-induced thrombocytopenia (HIT).[149] LMWH or fondaparinux are generally recommended over UFH.[105][112][143]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

fondaparinux

Secondary options

heparin

Back
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mechanical thromboprophylaxis

Thromboprophylaxis should be considered for all patients judged to be at risk for venous thromboembolism when admitted to hospital with an acute or critical medical illness (impairing mobility).[105][112]

If the patient is at high risk for major bleeding, mechanical thromboprophylaxis with graduated compression stockings (anti-embolism stockings) or intermittent pneumatic compression is recommended.[105][112]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day while the patient is mobilising or bathing.

If the bleeding risk decreases, pharmacological thromboprophylaxis should be considered.

Guideline recommendations may differ by region; refer to local guidelines for further context.

non-pregnant: with cancer

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low molecular weight heparin or direct oral anticoagulant or aspirin

Thromboprophylaxis for non-hospitalised (ambulatory) patients with cancer remains controversial and is not routinely recommended unless the patient has additional risk factors or cancer associated with a high-risk of VTE, such as multiple myeloma or pancreatic cancer.[147][150]​​​ Assessment using a validated VTE risk score (e.g., the Khorana score) may be used to help identify high-risk patients.[150]

Patients who are receiving systemic chemotherapy and are at high risk for thrombosis (e.g., Khorana score of ≥2 prior to initiating systemic chemotherapy) may be considered for thromboprophylaxis with a direct oral anticoagulant (apixaban or rivaroxaban) or LMWH.​​[145][147]​​[151][152]​​[153]

Patients with multiple myeloma who are receiving thalidomide (or its derivatives) with chemotherapy and/or dexamethasone are at high risk for venous thromboembolism and should receive concomitant aspirin (e.g., if ≤1 risk factor) or LMWH (e.g., if ≥2 risk factors), which should be given for the duration of treatment with thalidomide (or its derivatives).[91]​​​[145][147][148]

The UK guidelines recommend considering thromboprophylaxis for patients with pancreatic cancer receiving chemotherapy.​ NICE: venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism Opens in new window​ 

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

apixaban

OR

rivaroxaban

OR

aspirin

Back
1st line – 

low molecular weight heparin or unfractionated heparin or fondaparinux

Most patients with cancer and an acute medical condition or reduced mobility require pharmacological thromboprophylaxis with LMWH, unfractionated heparin, or fondaparinux during hospitalisation.​​[145]​​[146][147][148][150]

Hospitalised patients who are undergoing major cancer surgery require pharmacological thromboprophylaxis with LMWH, unfractionated heparin, or fondaparinux.​​[145]​​[147][148][150]

Guidelines from the American Society of Clinical Oncology (ASCO) recommend starting thromboprophylaxis preoperatively and continuing postoperatively for at least 7 to 10 days.[148]​ However, guidelines from the American Society of Hematology recommend starting thromboprophylaxis postoperatively in patients with cancer undergoing a surgical procedure.[145]

Extending thromboprophylaxis with LMWH for up to 4 weeks postoperatively is recommended for patients with cancer undergoing major open or laparoscopic abdominal or pelvic surgery with high-risk features (e.g., obesity, history of VTE, restricted mobility).​​[145]​​[147]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

OR

fondaparinux

Back
Consider – 

mechanical thromboprophylaxis

Additional treatment recommended for SOME patients in selected patient group

Mechanical thromboprophylaxis (e.g., graduated compression stockings [anti-embolism stockings] or intermittent pneumatic compression) may be added to pharmacological thromboprophylaxis (particularly in patients at high risk of thrombosis) in hospitalised cancer patients with an acute medical condition or undergoing surgery, but should not be used alone unless pharmacological thromboprophylaxis is contraindicated in the patients with cancer (e.g., due to active bleeding or a high risk for bleeding).​​[145][147][148]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

non-pregnant: undergoing non-orthopaedic surgery

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early mobilisation

For patients undergoing non-orthopaedic surgery (i.e., general, gynaecological, or urological) who are at very low risk for venous thromboembolism, early mobilisation is recommended and no pharmacological prophylaxis is required.[142]

Guideline recommendations may differ by region; refer to local guidelines for further context.

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mechanical thromboprophylaxis

For patients undergoing non-orthopaedic surgery (i.e., general, gynaecological, or urological) who are at low risk for venous thromboembolism, mechanical thromboprophylaxis with an intermittent pneumatic compression device is recommended.[142]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
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low molecular weight heparin, unfractionated heparin, or mechanical thromboprophylaxis

For patients undergoing general, gynaecological, or urological surgery who are at moderate risk for venous thromboembolism but not at high risk for major bleeding, a LMWH such as enoxaparin or dalteparin, low-dose unfractionated heparin, or an intermittent pneumatic compression device are recommended.[142]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
1st line – 

mechanical thromboprophylaxis

Patients undergoing general, gynaecological, or urological surgery who are at moderate risk for venous thromboembolism and at high risk for major bleeding, or for whom the consequences of major bleeding would be severe, should receive mechanical thromboprophylaxis with an intermittent pneumatic compression device.[142][154]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

If the bleeding risk decreases, pharmacological thromboprophylaxis should be considered.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
1st line – 

low molecular weight heparin or unfractionated heparin

Patients undergoing general, gynaecological, or urological surgery who are at high risk of venous thromboembolism but not at high risk for major bleeding should receive pharmacological prophylaxis with LMWH or low-dose unfractionated heparin.[142]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
Plus – 

mechanical thromboprophylaxis

Treatment recommended for ALL patients in selected patient group

Mechanical thromboprophylaxis (graduated compression stockings [anti-embolism stockings] or an intermittent pneumatic compression device) should be added to pharmacological prophylaxis with LMWH or low-dose unfractionated heparin, unless contraindicated.[142]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
2nd line – 

low-dose aspirin, fondaparinux, or mechanical thromboprophylaxis

Low-dose aspirin, fondaparinux, or mechanical thromboprophylaxis with an intermittent pneumatic compression device are preferred to no prophylaxis if pharmacological prophylaxis with LMWH or unfractionated heparin are contraindicated.[142]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

aspirin

OR

fondaparinux

Back
1st line – 

mechanical thromboprophylaxis

An intermittent pneumatic compression device is recommended for patients undergoing general, gynaecological, or urological surgery who are at high risk for venous thromboembolism and at high risk for major bleeding, or those for whom the consequences of bleeding are thought to be severe.[142]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

If the bleeding risk decreases, pharmacological thromboprophylaxis should be considered.

Guideline recommendations may differ by region; refer to local guidelines for further context.

non-pregnant: undergoing orthopaedic surgery

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direct oral anticoagulant, low molecular weight heparin, or aspirin

Thromboprophylaxis with a direct oral anticoagulant (apixaban, dabigatran, rivaroxaban), LMWH, or aspirin can be used in patients undergoing total hip or knee arthroplasty.[93][144]

The American College of Chest Physicians guidelines recommend LMWH as the preferred agent.[93] However, subsequent guidance published by the American Society of Hematology recommend direct oral anticoagulants.[144]

Dabigatran should be initiated 1 to 4 hours postoperatively. A reduced-dose regimen is recommended for those with moderate renal impairment, those aged >75 years, and those on amiodarone. It is not recommended in patients with mechanical prosthetic heart valves.

Apixaban should be given starting 12 to 24 hours postoperatively, provided haemostasis is established.

Rivaroxaban should be given commencing 6 to 10 hours postoperatively, provided haemostasis is established.

Aspirin should be given postoperatively.

An extended course of thromboprophylaxis (e.g., up to 5-6 weeks) is recommended.[93][144]

Early mobilisation lowers risk of venous thromboembolism following total hip arthroplasty replacement.[157]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

dabigatran

OR

apixaban

OR

rivaroxaban

OR

enoxaparin

OR

dalteparin

OR

aspirin

Back
Plus – 

mechanical thromboprophylaxis

Treatment recommended for ALL patients in selected patient group

Mechanical thromboprophylaxis with an intermittent pneumatic compression device can be added to pharmacological thromboprophylaxis.[93]

An extended course of thromboprophylaxis (e.g., up to 5-6 weeks) is recommended.[93][144] 

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Early mobilisation lowers risk of venous thromboembolism following total hip arthroplasty.[157]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
1st line – 

mechanical thromboprophylaxis

Mechanical thromboprophylaxis with an intermittent pneumatic compression device can be used alone in patients undergoing total hip or knee arthroplasty if risk of bleeding is a concern or there are contraindications to pharmacological agents.[93]

An extended course of thromboprophylaxis (e.g., up to 5-6 weeks) is recommended.[93][144] 

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Early mobilisation lowers risk of venous thromboembolism following total hip arthroplasty.[157]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
1st line – 

low molecular weight heparin, unfractionated heparin, fondaparinux, or aspirin

Pharmacological thromboprophylaxis with LMWH, unfractionated heparin, fondaparinux, or aspirin can be used in patients undergoing hip fracture surgery.[93][144]

If a delay in surgery is anticipated, LMWH should be started preoperatively between hospital admission and surgery, and at least 12 hours before surgery.[93]

Fondaparinux should be started 6 to 8 hours after surgery or on the following day.

Aspirin should be given postoperatively.

An extended course of thromboprophylaxis (e.g., up to 5-6 weeks) is recommended.[93][144]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

OR

fondaparinux

OR

aspirin

Back
Plus – 

mechanical thromboprophylaxis

Treatment recommended for ALL patients in selected patient group

Mechanical thromboprophylaxis with an intermittent pneumatic compression device can be added to pharmacological thromboprophylaxis in patients undergoing hip fracture surgery if risk of bleeding is a concern.[93]  

An extended course of thromboprophylaxis (e.g., up to 5-6 weeks) is recommended.[93][144]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
1st line – 

mechanical thromboprophylaxis

Mechanical thromboprophylaxis with an intermittent pneumatic compression device can be used alone in patients undergoing hip fracture surgery if risk of bleeding is a concern or there are contraindications to pharmacological agents.[93]

An extended course of thromboprophylaxis (e.g., up to 5-6 weeks) is recommended.[93][144]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day, while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

non-pregnant with major trauma

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low molecular weight heparin, unfractionated heparin, or mechanical thromboprophylaxis

Thromboprophylaxis with LMWH, low-dose unfractionated heparin (UFH), or an intermittent pneumatic compression device is recommended in major trauma patients who are at moderate risk for venous thromboembolism.[142][144]

Intermittent pneumatic compression alone is recommended (if not contraindicated) for major trauma patients in whom LMWH and low-dose UFH are contraindicated (e.g., due to bleeding risk).[142]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
1st line – 

low molecular weight heparin or unfractionated heparin

Pharmacological thromboprophylaxis with LMWH or low-dose unfractionated heparin is recommended for patients at high risk for venous thromboembolism (e.g., those with acute spinal cord injury, traumatic brain injury, and spinal surgery for trauma) if/when risk of bleeding allows.[142][144]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
Consider – 

mechanical thromboprophylaxis

Additional treatment recommended for SOME patients in selected patient group

Mechanical thromboprophylaxis with an intermittent pneumatic compression device can be added to pharmacological thromboprophylaxis in major trauma patients who are at high risk for venous thromboembolism (e.g., those with acute spinal cord injury, traumatic brain injury, and spinal surgery for trauma), when not contraindicated by lower extremity injury.[142][144][154]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
2nd line – 

mechanical thromboprophylaxis

Mechanical thromboprophylaxis with an intermittent pneumatic compression device alone is recommended (if not contraindicated) for major trauma patients who are at high risk for venous thromboembolism if LMWH and low-dose unfractionated heparin are contraindicated (e.g., due to bleeding risk).[142]

If mechanical thromboprophylaxis is used long-term, compression devices should be removed for only a short time each day while the patient is mobilising or bathing.

Guideline recommendations may differ by region; refer to local guidelines for further context.

Back
Consider – 

low molecular weight heparin or unfractionated heparin

Additional treatment recommended for SOME patients in selected patient group

Pharmacological prophylaxis with LMWH or low-dose unfractionated heparin may be added to mechanical thromboprophylaxis when the risk of bleeding reduces or the contraindication to heparin resolves.[142]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

pregnant

Back
1st line – 

low molecular weight heparin or unfractionated heparin

Optimal management of asymptomatic pregnant women with hereditary thrombophilia remains controversial due to lack of evidence and differences in guideline recommendations.

The American College of Chest Physicians recommends an individual risk assessment for asymptomatic pregnant women with heritable thrombophilia, with antenatal clinical surveillance or pharmacological thromboprophylaxis (LMWH or unfractionated heparin) and postnatal thromboprophylaxis for 4 to 6 weeks.[44]

The American Society of Hematology recommends antenatal and postnatal thromboprophylaxis for women with a family history of venous thromboembolism who have antithrombin deficiency.[159]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
1st line – 

clinical surveillance or low molecular weight heparin or unfractionated heparin

Optimal management of asymptomatic pregnant women with hereditary thrombophilia remains controversial due to lack of evidence and differences in guideline recommendations.

The American College of Chest Physicians recommends an individual risk assessment for asymptomatic women with other heritable thrombophilia, with antenatal clinical surveillance or pharmacological thromboprophylaxis (LMWH or unfractionated heparin) and postnatal thromboprophylaxis for 4 to 6 weeks.[44]

The American Society of Hematology guidelines recommend antenatal and postnatal thromboprophylaxis for women who are homozygous for the factor V Leiden mutation or who have combined thrombophilias, regardless of family history of venous thromboembolism (VTE).[159] The guidelines also recommend postnatal thromboprophylaxis for women with a family history of VTE who have protein C or protein S deficiency, and for women who are homozygous for the prothrombin gene mutation regardless of family history of VTE.[159]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
1st line – 

low molecular weight heparin or unfractionated heparin plus aspirin

For women with antiphospholipid syndrome with history of recurrent miscarriage or late pregnancy loss but no prior venous thromboembolism or arterial thrombosis, prophylactic LMWH or unfractionated heparin, in addition to aspirin, is recommended throughout pregnancy.[44]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

or

dalteparin

or

heparin

-- AND --

aspirin

Back
1st line – 

low molecular weight heparin, unfractionated heparin, or mechanical thromboprophylaxis

For women considered at low risk of venous thromboembolism (VTE) after caesarean section, early frequent mobilisation is recommended without thromboprophylaxis.[44]

For women considered at moderate risk of VTE after caesarean section because of the presence of one major risk factor in addition to pregnancy and ceasarean section, pharmacological thromboprophylaxis (LMWH or unfractionated heparin) or mechanical thromboprophylaxis (e.g., graduated compression stockings [anti-embolism stockings] or intermittent pneumatic compression devices) in those with contraindications to anticoagulants, is recommended while in hospital following delivery.[44]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
1st line – 

low molecular weight heparin or unfractionated heparin

For women with multiple additional risk factors for thromboembolism who are undergoing caesarean section and considered to be at high risk of venous thromboembolism, pharmacological thromboprophylaxis with LMWH or unfractionated heparin is recommended while in hospital following delivery.[44]

Guideline recommendations may differ by region; refer to local guidelines for further context.

Dose varies according to indication; consult local specialist protocol for guidance on dose.

Primary options

enoxaparin

OR

dalteparin

OR

heparin

Back
Plus – 

mechanical thromboprophylaxis

Treatment recommended for ALL patients in selected patient group

Combining mechanical thromboprophylaxis (e.g., graduated compression stockings [anti-embolism stockings] and/or an intermittent pneumatic compression device) with pharmacological thromboprophylaxis is recommended for women undergoing caesarean section who are at high risk of venous thromboembolism with multiple additional risk factors for thromboembolism.[44]

Guideline recommendations may differ by region; refer to local guidelines for further context.

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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