It is preferable and safer to prevent deep venous thrombosis (DVT) than to treat it, particularly in patients who are at risk. The general principles of DVT prevention are assessing the risk of DVT, assessing the risk and consequences of bleeding, and choosing a DVT prevention approach (1, 2, 3). Preventive measures include:
Ambulation and prevention of immobility
Prophylactic anticoagulation (eg, low molecular weight heparin [LMWH], fondaparinux, adjusted-dose warfarin, direct oral anticoagulant)(eg, low molecular weight heparin [LMWH], fondaparinux, adjusted-dose warfarin, direct oral anticoagulant)
Specific risk assessment tools and recommendations vary orthopedic surgery patients, nonorthopedic surgery patients, and medical patients.
(See also Deep Venous Thrombosis.)
General references
1. Anderson DR, Morgano GP, Bennett C, et al. American Society of Hematology 2019 guidelines for management of venous thromboembolism: prevention of venous thromboembolism in surgical hospitalized patients. Blood Adv. 2019;3(23):3898-3944. doi:10.1182/bloodadvances.2019000975
2. Schünemann HJ, Cushman M, Burnett AE, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: prophylaxis for hospitalized and nonhospitalized medical patients. Blood Adv. 2018;2(22):3198-3225. doi:10.1182/bloodadvances.2018022954
3. Gould MK, Garcia DA, Wren SM, et al. Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e227S-e277S. doi:10.1378/chest.11-2297
Risk Assessment in DVT Prevention
An individualized risk assessment is recommended for hospitalized patients using validated tools to guide prophylaxis decisions.
For surgical patients, risk of DVT is based on the specific procedure as well as patient-specific factors. Risk assessment tools, including the Caprini and Rogers scores, are useful for assessing risk after nonorthopedic surgical procedures (see ) (1). These models incorporate clinical risk factors (eg, reduced mobility, previous DVT, acute infection) to categorize the patient's risk for DVT (eg, low, high).
For medical patients, risk of DVT is based on the cause and severity of the underlying illness as well as patient-specific risk factors. Risk assessment tools include the Padua and IMPROVE venous thromboembolism (VTE) scores (2). Bleeding risk can be estimated using the IMPROVE bleeding risk score. Patients being treated in a critical care unit, or those with heart failure, cancer, respiratory failure, prolonged (≥ 3 days) immobilization, hormonal medications, known thrombophilia, prior VTE, age ≥ 70 years) are at higher risk for VTE (3).
Risk of Deep Venous Thrombosis and Pulmonary Embolism in Surgical Patients
Risk Category | Approximate Risk of DVT/PE (%) | Caprini Score | Rogers Score | Examples | Preventive Measures |
|---|---|---|---|---|---|
Very Low | < 0.5 | 0 | < 7 | Minor procedures (< 30–45 minutes) in patients < 40 years with no risk factors | No mechanical or pharmacologic prophylaxis |
Low | 1.5 | 1–2 | 7–10 | Major surgery (>45 minutes) in patients < 40 years Patients 40–74 years with no other risk factors Pregnant or postpartum patients | IPC |
Moderate | 3 | 3–4 | > 10 | Patients ≥ 75 years with no other risk factors Family history of VTE Known thrombophilia Major surgery in patients < 40 years with no other clinical risk factors | LMWH, LDUH, or IPC |
High | 6 | ≥ 5 | — | Major orthopedic surgery (arthroplasty, hip or pelvis fracture)> Acute spinal cord injury Multiple risk factors | LMWH or LDUH, and IPC Extended LMWH after abdominal/pelvic surgery for cancer IPC if high bleeding risk; aspirin + fondaparinux or IPC if heparin contraindicatedIPC if high bleeding risk; aspirin + fondaparinux or IPC if heparin contraindicated |
DVT = deep venous thrombosis; IPC = intermittent pneumatic compression; LDUH = low-dose unfractionated heparin; LMWH = low molecular weight heparin; PE = pulmonary embolism.DVT = deep venous thrombosis; IPC = intermittent pneumatic compression; LDUH = low-dose unfractionated heparin; LMWH = low molecular weight heparin; PE = pulmonary embolism. | |||||
Data from Gould MK, Garcia DA, Wren SM, et al. Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e227S-e277S. doi:10.1378/chest.11-2297Ada | |||||
Risk assessment references
1. Gould MK, Garcia DA, Wren SM, et al. Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e227S-e277S. doi:10.1378/chest.11-2297
2. Schünemann HJ, Cushman M, Burnett AE, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: prophylaxis for hospitalized and nonhospitalized medical patients. Blood Adv. 2018;2(22):3198-3225. doi:10.1182/bloodadvances.2018022954
3. Kahn SR, Lim W, Dunn AS, et al. Prevention of VTE in nonsurgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e195S-e226S. doi:10.1378/chest.11-2296
Method of 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 for DVT and risk of bleeding, type of surgery (if applicable), projected duration of preventive treatment, contraindications, adverse effects, relative cost, ease of use, and local practice.
In general, patients undergoing major surgery should receive mechanical or pharmacologic prophylaxis, with mechanical prophylaxis preferable in patients with higher risk of bleeding (1, 2). Although major surgeries are not strictly defined, they typically include high-risk procedures such as those involving open abdominal or pelvic surgery, cancer surgery, major trauma, and surgeries with prolonged immobility, whereas minor surgeries include short laparoscopic operations or minor soft tissue procedures. For certain higher-risk procedures both mechanical and pharmacologic prophylaxis are suggested. For patients undergoing major orthopedic surgery, such as total hip or knee arthroplasty or surgery for hip fracture, pharmacologic prophylaxis with direct oral anticoagulants, LMWH, usually for 10 to 35 days, is recommended (1, 3). If bleeding risk is high, mechanical prophylaxis is an option.
For patients undergoing transurethral resection of the prostate, laparoscopic cholecystectomy, and most neurosurgical procedures, pharmacologic prophylaxis is generally not recommended.
Patients acutely or critically ill and hospitalized for nonsurgical conditions are usually given pharmacologic prophylaxis with LMWH or low-dose unfractionated heparin (UFH or LDUH) (Patients acutely or critically ill and hospitalized for nonsurgical conditions are usually given pharmacologic prophylaxis with LMWH or low-dose unfractionated heparin (UFH or LDUH) (4, 5). Mechanical prophylaxis is used if bleeding risk or other factors preclude heparin (). Mechanical prophylaxis is used if bleeding risk or other factors preclude heparin (4, 5). Anticoagulation is typically discontinued at hospital discharge.
Mechanical therapy for DVT prophylaxis
After surgery, early mobilization is likely to reduce the risk of postoperative DVT.
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 (1, 2). 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 (1, 2).
Inferior vena cava filters are not indicated for primary prevention of DVT.
Pharmacologic therapy for DVT prophylaxis
Pharmacologic thromboprophylaxis involves use of anticoagulants.
Low molecular weight heparins (LMWHs) are more effective than low-dose UFH for preventing DVT and PE (6, 7, 8). LMWH is the preferred agent for patients undergoing moderate to high-risk nonorthopedic surgeries and for medical patients who are acutely and critically ill (1, 2, 4, 5). For patients undergoing major orthopedic surgery, LMWH may also be used for thromboprophylaxis, although direct oral anticoagulants are generally preferred (3). 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 (). 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 (9). Prophylaxis is usually discontinued upon discharge, except after total knee or hip arthroplasty or hip fracture surgery, where it is continued for 14 to 35 days.
Low-dose unfractionated heparinLow-dose unfractionated heparin (UFH, or LDUH) can be used for patients undergoing moderate or high-risk nonorthopedic procedures or major orthopedic procedures and for medical inpatients; however, in most situations LMWH is preferred (1, 2, 5). Dosing is 5000 units subcutaneously 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 are bedbound but are not undergoing surgery are given 5000 units subcutaneously every 12 hours until risk factors are reversed.
Direct oral anticoagulants (DOACs, eg, dabigatran, rivaroxaban, apixaban) are preferred over LMWH and UFH for preventing DVT and PE after hip or knee replacement surgery.((DOACs, eg, dabigatran, rivaroxaban, apixaban) are preferred over LMWH and UFH for preventing DVT and PE after hip or knee replacement surgery.(1, 3, 7).
Fondaparinux is an alternative to heparins but is not a first-line anticoagulant due to bleeding risk and renal toxicity (Fondaparinux is an alternative to heparins but is not a first-line anticoagulant due to bleeding risk and renal toxicity (2, 3, 5).
WarfarinWarfarin, using a target international normalized ratio (INR) of 2.0 to 3.0,may be used in orthopedic surgery, but other agents are preferred (1, 3).
The role of aspirin for DVT prophylaxis is largely limited to patients undergoing total hip or knee replacement surgery (1, 3, 10).
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, thromboprophylaxis with selected direct oral anticoagulants (eg, rivaroxaban, apixaban), LMWH, fondaparinux, or adjusted-dose warfarin is recommended (For hip and other lower extremity orthopedic surgery, thromboprophylaxis with selected direct oral anticoagulants (eg, rivaroxaban, apixaban), LMWH, fondaparinux, or adjusted-dose warfarin is recommended (1, 3). 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 14 days after total knee replacement and 28 days after total hip replacement. For hip fracture repair surgery, preventive treatment should be given for 14 to 35 days, depending on the patient's mobility status. 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 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 14 days after total knee replacement and 28 days after total hip replacement. For hip fracture repair surgery, preventive treatment should be given for 14 to 35 days, depending on the patient's mobility status. 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 (9).
For elective neurosurgery, mechanical prophylaxis is preferred (1). For neurosurgery or trauma in patients with low to moderate bleeding risk where pharmacologic prophylaxis is used, low-dose LMWH is the first option, or low-dose UFH is recommended.
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 (11, 12, 13, 14).
Patients who are traveling for long periods (eg, airplane flight > 4 hours), ambulation and calf exercises are recommended over compression stockings, aspirin, or LMWH (Patients who are traveling for long periods (eg, airplane flight > 4 hours), ambulation and calf exercises are recommended over compression stockings, aspirin, or LMWH (5). However, for travelers with 2 DVT risk factors (recent surgery, history of DVT, pregnant or postpartum persons, active malignancy, hormone replacement therapy, obesity), compression stockings or LMWH can be considered.
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.
