VTE Prevention in Medical Patients & During Pregnancy

Primary preventive measures can reduce morbidity and mortality

Venous thromboembolism (VTE) is a well-recognised cause of preventable morbidity and mortality in hospitalised patients. About one in four cases of VTE is associated with hospitalisation, and VTE may occur in patients hospitalised to treat medical illness as well in those undergoing surgery.^{3, 64}

Deep vein thrombosis (DVT) is often asymptomatic. The first sign of thrombosis may be pulmonary embolism (PE) — a potentially fatal cardiovascular event, responsible for between 5% and 10% of deaths in the hospital.⁶⁴ Therefore, waiting for the signs and symptoms of VTE to appear before instituting anticoagulant treatment increases the risk of morbidity and mortality. The most effective approach to decreasing the burden of VTE is primary prophylaxis (by improving venous return or decreasing coagulability) in patients at high risk.⁶⁴

VTE prevention with pharmacologic treatment

Anticoagulant therapy with unfractionated heparin, low-molecular-weight heparin (LMWH), and fondaparinux in high-risk medical patients has been shown to reduce the incidence of VTE (both symptomatic and asymptomatic DVT detected by venography or ultrasound).^{67, 68, 69, 119} While this means of prophylaxis has been more extensively studied in surgical than in medical patients, the balance of evidence from trials involving medical patients provides strong support for this approach. There is less-conclusive data about the impact on fatal and nonfatal PE, although a recent meta-analysis indicated a treatment benefit.⁶⁹

VTE prevention with nonpharmacologic approaches

Both early ambulation and foot extension exercises help minimise venous stasis and should be encouraged. While a number of clinical trials have shown a benefit for graduated compression stockings and pneumatic leg compression devices postoperatively, these methods have not been well studied in hospitalised medical patients. In addition, meaningful research in this area is hampered by the lack of blinding.⁶⁴ These methods of prophylaxis should be employed for patients with an elevated risk of bleeding complications from anticoagulant therapy.

VTE prevention in heart failure

According to current guidelines, all hospitalised patients with heart failure who are not at high risk for bleeding should receive prophylactic treatment with low-dose unfractionated heparin (LDUH), low-molecular-weight heparin (LMWH) or fondaparinux.³ However, there remains a significant gap between these guidelines and clinical practice. This may be due to lack of awareness, inadequate institutional protocols or uncertainties regarding the risk of bleeding.²⁴⁷ Improved physician-patient communication, as well as timely follow-up after hospitalisation, can help improve treatment adherence and ensure that patients are aware of the risk/benefit ratio of anticoagulation in heart failure.²⁴⁷

VTE prevention in the hospitalised, medically ill patient

While VTE risk is often considered in surgical or trauma patients, it is important to note that hospitalisation for acute medical illness poses an 8-fold increase in the relative risk for VTE and that roughly 1 out of every 4 VTE events occurs in patients in hospital because of medical illness.³ Guidelines from the American College of Chest Physicians (ACCP) for preventing VTE recommend either LDUH, LMWH or fondaparinux for acutely ill medical patients with specific risk factors.³ These risks include confinement to bed, congestive heart failure or severe respiratory disease, plus 1 or more additional risk factors (eg, active cancer, history of VTE, sepsis, acute neurological illness or inflammatory bowel disease).³ (See previous section for more information about VTE prevention in heart failure.) However, the multinational, epidemiologic ENDORSE study, published in 2008, reported that approximately 40% of medical patients at risk for VTE based on the ACCP criteria actually received appropriate VTE prophylaxis.⁵⁷ This finding identifies a significant gap between optimal preventive treatment and actual clinical practice in many settings.

VTE prevention in pregnancy

DVT occurs with comparable frequency in each trimester and after childbirth, while PE occurs more commonly after childbirth.¹⁸² The ACCP recommends anticoagulation therapy for pregnant women with a history of thrombosis to prevent recurrent events.¹⁶¹ Patients already on anticoagulant therapy should continue treatment during pregnancy.¹⁶¹ However, warfarin should be avoided during pregnancy because of its teratogenic effects.¹⁶¹ Instead, heparin products are currently recommended for DVT prevention and treatment in pregnant women.¹⁶¹ These women should also receive thromboprophylaxis during the first 2 to 6 weeks postpartum.^{161, 208} Thromboprophylaxis after childbirth may be indicated for other women due to prolonged labour, mid-forceps delivery and immobility after delivery.¹⁸²

Print page

Email page

Treatment of Established DVT and PE >

Article references

3 - 1. Geerts WH, Bergqvist D, Pineo GF, et al. Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6)(suppl):381S-453S.
64 - Francis CW. Clinical practice. Prophylaxis for thromboembolism in hospitalized medical patients. N Engl J Med. 2007;356(14):1438-1444.
67 - Cohen AT, Davidson BL, Gallus AS, et al; ARTEMIS Investigators. Efficacy and safety of fondaparinux for the prevention of venous thromboembolism in older acute medical patients: randomised placebo controlled trial. BMJ. 2006;332(7537):325-329.
68 - Samama MM, Cohen AT, Darmon JY, et al. A comparison of enoxaparin with placebo for the prevention of venous thromboembolism in acutely ill medical patients. Prophylaxis in Medical Patients with Enoxaparin Study Group. N Engl J Med. 1999;341(11):793-800.
69 - Dentali F, Douketis JD, Gianni M, Lim W, Crowther MA. Meta-analysis: anticoagulant prophylaxis to prevent symptomatic venous thromboembolism in hospitalized medical patients. Ann Intern Med. 2007;146(4):278-288.
119 - Leizorovicz A, Cohen AT, Turpie AG, Olsson CG, Vaitkus PT, Goldhaber SZ; PREVENT Medical Thromboprophylaxis Study Group. Randomized, placebo-controlled trial of dalteparin for the prevention of venous thromboembolism in acutely ill medical patients. Circulation. 2004;110(7):874-879.
247 - Ng TM, Tsai F, Khatri N, Barakat MN, Elkayam U. Venous thromboembolism in hospitalized patients with heart failure: incidence, prognosis, and prevention. Circ Heart Fail. 2010;3(1):165-173.
57 - Cohen AT, Tapson VF, Bergmann JF, et al; ENDORSE Investigators. Venous thromboembolism risk and prophylaxis in the acute hospital care setting (ENDORSE study): a multinational cross-sectional study. Lancet. 2008;371(9610):387-394.
182 - Dresang LT, Fontaine P, Leeman L, King VJ. Venous thromboembolism during pregnancy. Am Fam Physician. 2008;77(12):1709-1716.
161 - Bates SM, Greer IA, Pabinger I, Sofaer S, Hirsh J. Venous thromboembolism, thrombophilia, antithrombotic therapy, and pregnancy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6)(suppl):844S-886S.
208 - James AH. Pregnancy and thrombotic risk. Crit Care Med. 2010;38(2)(suppl):S57-S63.

Venous thromboembolism: A condition in which a blood clot (thrombus) forms in a vein, which in some cases then breaks free and enters the circulation as an embolus, finally lodging in and completely obstructing a blood vessel, e.g., in lungs causing a PE. The term encompasses both DVT and PE.
Prophylaxis: The prevention of a disease or pathological condition.
Fondaparinux: An indirect Factor Xa inhibitor comprising a synthetic pentasaccharide sequence matching the part of the heparin molecule that binds to antithrombin. It is administered by subcutaneous injection.
Heparin: An anticoagulant that exerts its activity by binding to antithrombin and greatly increasing its activity. The principal coagulation factors inhibited by heparin are Factors IIa and Xa. It is administered by intravenous or subcutaneous injection.
Venography: An X-ray of the veins performed by first injecting a radiopaque contrast (shows up on X-ray) into the vein in question and then taking a conventional X-ray. Used to demonstrate blockage of a vein. Commonly used in the lower extremities to diagnose DVT.
Venous stasis: The presence of an abnormally low rate of blood flow in the veins. This can be caused by, for example, the use of a tourniquet or prolonged immobility.
American College of Chest Physicians: Multidisciplinary international medical society based in Northbrook, Illinois, USA, that focuses on the treatment and prevention of all diseases of the chest. It has over 16,000 active members with physicians representing all chest medicine disciplines. Publishes the journal Chest.
Congestive heart failure: Congestive heart failure (CHF) is a condition with impaired ability of the heart to fill with or pump a sufficient amount of blood through the body. Typical symptoms include shortness of breath with exertion, difficulty breathing when lying flat and leg or ankle swelling.
Low-molecular-weight heparin: An anticoagulant derived from unfractionated heparin (UFH), containing only the low-molecular-weight molecules of heparin. It binds to antithrombin, greatly increasing its activity. It inhibits coagulation Factor Xa and, to a lesser extent, Factor IIa. LMWHs are administered by subcutaneous injection.
Thromboprophylaxis: The use of medication or medical devices to prevent the formation of blood clots.
Warfarin: A vitamin K antagonist. Most commonly used oral anticoagulant in chronic prevention or treatment of VTE.