It is preferable and safer to prevent deep venous thrombosis (DVT) than to treat it, particularly in patients who are at high risk (see table Risk of Deep Venous Thrombosis and Pulmonary Embolism). DVT prophylaxis begins with risk assessment. Risk, along with other factors, allows the proper preventive modality to be selected. Preventive measures include
Prevention of immobility
Prophylactic anticoagulation (eg, low molecular weight heparin, fondaparinux, adjusted-dose warfarin, direct oral anticoagulant)(eg, low molecular weight heparin, fondaparinux, adjusted-dose warfarin, direct oral anticoagulant)
Inferior vena cava (IVC) filters do not prevent DVT but are sometimes placed in an attempt to prevent pulmonary embolism (PE). An IVC filter may be used to help prevent PE in patients with lower extremity DVT who have contraindications to anticoagulant therapy or in patients with recurrent DVT (or emboli) despite adequate anticoagulation. Despite widespread use of IVC filters, efficacy in preventing PE is unstudied and unproven.
(See also Deep Venous Thrombosis.)
Risk Assessment in DVT Prevention
Patients at low risk of DVT (eg, those who are undergoing minor surgery but have no clinical risk factors for DVT, those who must be temporarily inactive for long periods, as during a prolonged [> 6 hour] airplane flight) should be encouraged to walk or otherwise move their legs periodically; no medical treatment is needed. Dorsiflexion 10 times/hour is probably sufficient.
Patients at higher risk of DVT include those undergoing minor surgery if they have clinical risk factors for DVT; those undergoing major surgery, especially orthopedic surgery, even without risk factors; and bedbound patients with major medical illnesses (eg, most patients being treated in a critical care unit, other patients with heart failure, chronic obstructive pulmonary disease [COPD], chronic liver disease, stroke). These patients require additional preventive treatment (see table Risk of Deep Venous Thrombosis and Pulmonary Embolism). Most of these patients can be identified and should receive DVT prophylaxis. Hospitalization itself is not considered a risk factor, and patients who are hospitalized but not in one of these categories do not require routine DVT prophylaxis.
Risk of Deep Venous Thrombosis and Pulmonary Embolism in Surgical Patients
Risk Category | Examples | Preventive Measures | Risk of DVT/PE (%) | |||
|---|---|---|---|---|---|---|
Calf | Proximal | PE | Fatal PE | |||
Low | Nonmajor surgery* in patients < 40 years with no clinical risk factors | Early and aggressive ambulation | 2 | 0.4 | 0.2 | 0.002 |
Moderate | Nonmajor surgery in patients with risk factors Minor surgery in patients 40–60 years with no clinical risk factors Major surgery in patients < 40 years with no other clinical risk factors Immobilized patients with major medical illnesses | LDUH every 12 hours, LMWH, fondaparinux, or IPC, with or without elastic stockingsLDUH every 12 hours, LMWH, fondaparinux, or IPC, with or without elastic stockings | 10–20 | 2–4 | 1–2 | 0.1–0.4 |
High | Nonmajor surgery in patients > 60 years or 40–60 years with risk factors Major surgery in patients > 40 years or with other clinical risk factors | LDUH every 8 hours, LMWH, fondaparinux, or IPCLDUH every 8 hours, LMWH, fondaparinux, or IPC | 20–40 | 4–8 | 2–4 | 0.4–1.0 |
Very high | Major surgery in patients > 40 years who have had a previous venous thromboembolic, malignant, or hypercoagulability disorder In patients of any age:
| LMWH, oral anticoagulation, IPC, or elastic stockings plus either LDUH every 8 hours or LMWH Fondaparinux if patients have had orthopedic, abdominal, or thoracic surgery or have an acute, severe illnessFondaparinux if patients have had orthopedic, abdominal, or thoracic surgery or have an acute, severe illness LMWH or DOAC in some high-risk patients with cancer undergoing chemotherapy | 40–80 | 10–20 | 4–10 | 0.2–5 |
* Nonmajor surgery is defined here as an operation that does not involve general anesthesia or respiratory assistance. | ||||||
DOAC = direct oral anticoagulant; DVT = deep venous thrombosis; PE = pulmonary embolism; LDUH = low-dose unfractionated heparin; LMWH = low molecular weight heparin; IPC = intermittent pneumatic compression.DOAC = direct oral anticoagulant; DVT = deep venous thrombosis; PE = pulmonary embolism; LDUH = low-dose unfractionated heparin; LMWH = low molecular weight heparin; IPC = intermittent pneumatic compression. | ||||||
Adapted with permission from Geerts WH, Heit JA, Clagett GP, et al: Prevention of venous thromboembolism. Chest 119:132S–175S, 2001. | ||||||
Treatment in DVT Prevention
DVT prophylaxis can involve one or more of the following:
Mechanical therapy (eg, compression devices or stockings, venous filters)
Pharmacologic therapy (including low-dose unfractionated heparin, low molecular weight heparins, warfarin, fondaparinux, direct oral anticoagulants)Pharmacologic therapy (including low-dose unfractionated heparin, low molecular weight heparins, warfarin, fondaparinux, direct oral anticoagulants)
Choice depends on patient’s risk level, type of surgery (if applicable), projected duration of preventive treatment, contraindications, adverse effects, relative cost, ease of use, and local practice.
Mechanical therapy for DVT prophylaxis
After surgery, elevating the legs and avoiding prolonged immobility, which places the legs in a dependent position thereby impeding venous return, can help.
The benefit of graded compression stockings is questionable except for low-risk surgical patients and selected hospitalized medical patients. However, combining stockings with other preventive measures may be more protective than any single approach.
Intermittent pneumatic compression (IPC) uses a pump to cyclically inflate and deflate hollow plastic leggings, providing external compression to the lower legs and sometimes thighs. IPC may be used instead of or in combination with anticoagulants after surgery. IPC is recommended for patients undergoing surgery associated with a high risk of bleeding in whom anticoagulant use may be contraindicated. IPC is probably more effective for preventing calf DVT than proximal DVT. IPC is contraindicated in some patients who have obesity and may be unable to apply the devices properly.
For patients who are at very high risk of DVT and bleeding (eg, after major trauma), IPC is recommended until the bleeding risk subsides and anticoagulants can be given.
The use of inferior vena cava filters should be avoided unless DVT has been confirmed, except in highly selected patients.
Pharmacologic therapy for DVT prophylaxis
Pharmacologic thromboprophylaxis involves use of anticoagulants.
The role of aspirin for DVT prophylaxis is largely limited to patients undergoing total hip or knee replacement surgery (1).
Low-dose unfractionated heparin (UFH) 5000 units subcutaneously is given 2 hours before surgery and every 8 to 12 hours thereafter for 7 to 10 days or until patients are fully ambulatory. Patients who bedbound but are not undergoing surgery are given 5000 units subcutaneously every 12 hours until risk factors are reversed.Low-dose unfractionated heparin (UFH) 5000 units subcutaneously is given 2 hours before surgery and every 8 to 12 hours thereafter for 7 to 10 days or until patients are fully ambulatory. Patients who bedbound but are not undergoing surgery are given 5000 units subcutaneously every 12 hours until risk factors are reversed.
LMWHs are more effective than low-dose UFH for preventing DVT and PE (2, 3, 4), but widespread use is limited by cost. Enoxaparin 30 mg subcutaneously every 12 hours, dalteparin 5000 units subcutaneously once a day, and tinzaparin 4500 units subcutaneously once a day appear to be equally effective. Fondaparinux 2.5 mg subcutaneously once a day is at least as effective as LMWH in patients who are undergoing nonorthopedic surgery and is possibly more effective than LMWHs after orthopedic surgery (), but widespread use is limited by cost. Enoxaparin 30 mg subcutaneously every 12 hours, dalteparin 5000 units subcutaneously once a day, and tinzaparin 4500 units subcutaneously once a day appear to be equally effective. Fondaparinux 2.5 mg subcutaneously once a day is at least as effective as LMWH in patients who are undergoing nonorthopedic surgery and is possibly more effective than LMWHs after orthopedic surgery (5).
Warfarin, using a target international normalized ratio (INR) of 2.0 to 3.0, is proven to be effective in orthopedic surgery but is being used less frequently because alternative anticoagulants such as LMWHs and direct oral anticoagulants are easier to administer.Warfarin, using a target international normalized ratio (INR) of 2.0 to 3.0, is proven to be effective in orthopedic surgery but is being used less frequently because alternative anticoagulants such as LMWHs and direct oral anticoagulants are easier to administer.
Direct oral anticoagulants (eg, dabigatran, rivaroxaban, apixaban) are at least as effective and safe as LMWH for preventing DVT and PE after hip or knee replacement surgery but are more expensive than Direct oral anticoagulants (eg, dabigatran, rivaroxaban, apixaban) are at least as effective and safe as LMWH for preventing DVT and PE after hip or knee replacement surgery but are more expensive thanwarfarin, and their cost-effectiveness requires further study (3).
With DVT prophylaxis, there is always a risk of bleeding during use of anticoagulants.
DVT prophylaxis in selected populations
For hip and other lower extremity orthopedic surgery, selected direct oral anticoagulants (eg, rivaroxaban, apixaban), LMWH, fondaparinux, or adjusted-dose warfarin is recommended. For patients undergoing total knee replacement and some other patients at high risk in whom anticoagulants cannot be given because of a high risk of bleeding, IPC is also beneficial. For orthopedic surgery, preventive treatment may be started before or after surgery and continued for at least 14 days. Fondaparinux 2.5 mg subcutaneously once a day appears to be more effective to prevent DVT than LMWH for patients undergoing orthopedic surgery but may be associated with an increased risk of bleeding (For hip and other lower extremity orthopedic surgery, selected direct oral anticoagulants (eg, rivaroxaban, apixaban), LMWH, fondaparinux, or adjusted-dose warfarin is recommended. For patients undergoing total knee replacement and some other patients at high risk in whom anticoagulants cannot be given because of a high risk of bleeding, IPC is also beneficial. For orthopedic surgery, preventive treatment may be started before or after surgery and continued for at least 14 days. Fondaparinux 2.5 mg subcutaneously once a day appears to be more effective to prevent DVT than LMWH for patients undergoing orthopedic surgery but may be associated with an increased risk of bleeding (5).
For elective neurosurgery, spinal cord injury, or multiple trauma, low-dose LMWH, as the first option, or low-dose UFH is recommended.
For patients undergoing neurosurgery, physical measures (IPC, elastic stockings) have been used because intracranial bleeding is a concern; however, LMWH appears to be an acceptable alternative. Limited data support the combination of IPC, elastic stockings, and LMWH in patients with spinal cord injury or multiple trauma.
Preventive treatment is also indicated for patients who have a major medical illnesses that require bed rest (eg, myocardial infarction, ischemic stroke, heart failure). Low-dose UFH or LMWH is effective in patients who are not already receiving IV heparin or thrombolytics; IPC, elastic stockings, or both may be used when anticoagulants are contraindicated. For select patients with cancer who are at high risk (eg, those with advanced ). Low-dose UFH or LMWH is effective in patients who are not already receiving IV heparin or thrombolytics; IPC, elastic stockings, or both may be used when anticoagulants are contraindicated. For select patients with cancer who are at high risk (eg, those with advancedpancreatic cancer) who are receiving chemotherapy, primary prophylaxis with LMWH or certain direct oral anticoagulants (apixaban or rivaroxaban) may be considered () who are receiving chemotherapy, primary prophylaxis with LMWH or certain direct oral anticoagulants (apixaban or rivaroxaban) may be considered (6, 7, 8, 9).
Prevention of post-thrombotic syndrome
In patients with symptomatic DVT who develop symptoms of post-thrombotic syndrome (eg, leg swelling, pain, aching), the use of knee-high compression stockings providing 30 to 40 mm Hg pressure is recommended, although stockings with lower tension (20 to 30 mm Hg) can be considered if patients are unable to tolerate the higher tension stockings. However, the routine use of stockings in all patients who have had a DVT has been questioned by data from a meta-analysis of randomized trials, in which the use of compression stockings compared with placebo (none or sham-compression stockings) did not show a significant decrease in post-thrombotic syndrome) (10).
Treatment references
1. Ludwick L, Shohat N, Van Nest D, Paladino J, Ledesma J, Parvizi J: Aspirin May Be a Suitable Prophylaxis for Patients with a History of Venous Thromboembolism Undergoing Total Joint Arthroplasty. J Bone Joint Surg Am 104(16):1438–1446, 2022. doi:10.2106/JBJS.21.00601
2. McGarry LJ, Stokes ME, Thompson D: Outcomes of thromboprophylaxis with enoxaparin vs. unfractionated heparin in medical inpatients. Thromb J 4:17, 2006. doi:10.1186/1477-9560-4-17
3. Laporte S, Liotier J, Bertoletti L, et al: Individual patient data meta-analysis of enoxaparin vs. unfractionated heparin for venous thromboembolism prevention in medical patients. J Thromb Haemost 9(3):464–472, 2011. doi:10.1111/j.1538-7836.2011.04182.x
4. Neumann I, Rada G, Claro JC, et al: Oral direct Factor Xa inhibitors versus low-molecular-weight heparin to prevent venous thromboembolism in patients undergoing total hip or knee replacement: a systematic review and meta-analysis. Ann Intern Med 156(10):710–719, 2012. doi:10.7326/0003-4819-156-10-201205150-00421
5. Dong K, Song Y, Li X, et al: Pentasaccharides for the prevention of venous thromboembolism. Cochrane Database Syst Rev 10(10):CD005134, 2016. doi:10.1002/14651858.CD005134.pub3
6. Carrier M, Abou-Nassar K, Mallick R, et al: Apixaban to prevent venous thromboembolism in patients with cancer. N Engl J Med 380:711–719, 2019. doi: 10.1056/NEJMoa1814468
7. Farge D, Frere C, Connors JM, et al: 2019 international clinical practice guidelines for the treatment and prophylaxis of venous thromboembolism in patients with cancer. Lancet Oncol 20 (10): e566–e581, 2019. doi: 10.1016/S1470-2045(19)30336-5
8. Key NS, Khorana AA, Kuderer NM, et al: Venous thromboembolism prophylaxis and treatment in patients with cancer: ASCO Clinical Practice Guideline Update. J Clin Oncol 38:496–520, 2020. doi: 10.1200/JCO.19.01461
9. Khorana AA, Soff GA, Kakkar AK, et al: Rivaroxaban for thromboprophylaxis in high-risk ambulatory patients with cancer. N Engl J Med 380:720–728, 2019. doi: 10.1056/NEJMoa1814630
10. Subbiah R, Aggarwal V, Zhao H, Kolluri R, Chatterjee S, Bashir R: Effect of compression stockings on post thrombotic syndrome in patients with deep vein thrombosis: a meta-analysis of randomised controlled trials. Lancet Haematol 3(6):e293–e300, 2016. doi:10.1016/S2352-3026(16)30017-5
Key Points
Treatment to prevent deep venous thrombosis is required for patients who are bedbound with major illness and/or those undergoing certain surgical procedures.
Early mobilization, leg elevation, and an anticoagulant are the recommended preventive measures; patients who should not receive anticoagulants may benefit from intermittent pneumatic compression devices or elastic stockings.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Farge D, Frere C, Connors JM, et al: 2019 international clinical practice guidelines for the treatment and prophylaxis of venous thromboembolism in patients with cancer. Lancet Oncol 20 (10): e566–e581, 2019. doi: 10.1016/S1470-2045(19)30336-5
