Risk factors for venous thromboembolism
Modelling data indicate that multiple risk factors can increase the likelihood of Venous thromboembolism
- Surgery, especially major orthopaedic surgery involving the lower extremity and major surgery for cancer, is a prominent risk factor for the development of Venous thromboembolism (VTE)
- Immobilization, such as that experienced by many patients hospitalized for acute medical illnesses, is also a risk factor
- If a patient has multiple risk factors, there is generally a cumulative impact on the risk of Venous thromboembolism (VTE)
Major orthopaedic surgery
Major orthopaedic surgery, such as elective hip or knee replacement surgery and hip fracture surgery, is associated with a high risk of Venous thromboembolism
In the absence of prophylaxis
, the incidence of DVT (as assessed by venography): 3
- Ranges from 41% to 85% after elective hip or knee replacement surgery
- Is as high as 60% after hip fracture surgery
Other surgical patients
Venous thromboembolism (VTE) risk
in general and emergency surgery:55
- The incidence of DVT in patients undergoing general surgery without thromboprophylaxis is 15–30%; the risk of pulmonary embolism (PE) in this same group is approximately 0.08%
- Duration of hospitalization and type of surgery affect thrombosis risk, as do increasing age and other risk factors, such as cancer, prior Venous thromboembolism (VTE) and obesity
Venous thromboembolism (VTE) risk in laparoscopic surgery:55
- The relative risk of Venous thromboembolism (VTE) with laparoscopy versus open procedures has not yet been investigated in depth
- Based on the pathophysiology of Venous thromboembolism (VTE), factors that may heighten the risk with laparoscopy are duration of the procedure, patient positioning (e.g. reverse Trendelenberg position for some procedures) and the injection of air into the peritoneum
- Shorter hospital stays and more rapid postoperative mobilization would be expected to decrease the risk
Venous thromboembolism (VTE) risk in major gynaecological, major open urological and neurological surgery:
- Major gynaecological surgery poses a Venous thromboembolism (VTE) risk that is similar to the risk involved in general abdominal surgery (15–40% without preventive therapy) 3
- Major open urological procedures confer significant risk, but transurethral procedures do not3
- Venographic studies in patients undergoing neurosurgery show a rate of DVT of approximately 30%, with increased risks in cranial surgery compared with spinal surgery, in cases of malignant tumours compared to cases of benign tumours, and in patients with leg weakness56
Venous thromboembolism (VTE) risk in surgical patients
Surgery, especially major orthopaedic surgery involving the lower extremity and major surgery for cancer, is a prominent risk factor for the development of venous thromboembolism
And if a patient has many risk factors, there is generally a cumulative impact on Venous thromboembolism (VTE) risk
.3, 55, 56
Immobilization increases the risk of Venous thromboembolism
- Hospitalized medical patients are often immobile because of weakness, reduced alertness or nerve injury
- Patients in critical care settings are often bedridden
- Even in the absence of medical illness, lack of mobility can lead to venous stasis and Venous thromboembolism (VTE), as can occur during long-distance air travel1
often have multiple risk factors for Venous thromboembolism
- Risk factors are generally cumulative64
- All patients should be evaluated for their risk of Venous thromboembolism (VTE) at the time of hospital admission
- Evaluation should be repeated whenever there is a significant change in a patient’s clinical status
Although Venous thromboembolism
) is often associated with recent trauma or surgery, 50–70% of symptomatic cases, as well as the majority of cases of fatal PE, occur in medical (non-surgical, nontrauma) patients. 3
Prospective studies show that hospitalized medical patients at risk of Venous thromboembolism
) who do not receive preventive anticoagulant therapy develop distal DVT in the calf in 10–15% of cases. The same studies revealed an incidence of proximal DVT of 2–5% and of PE of 0.3–1.5%.64
- 3 - 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.
- 26 - Merli GJ. Pathophysiology of venous thrombosis, thrombophilia, and the diagnosis of deep vein thrombosis-pulmonary embolism in the elderly. Clin Geriatr Med. 2006;22(1):75-92, viii-ix.
- 59 - Planes A, Vochelle N, Darmon JY, Fagola M, Bellaud M, Huet Y. Risk of deep-venous thrombosis after hospital discharge in patients having undergone total hip replacement: double-blind randomised comparison of enoxaparin versus placebo. Lancet. 1996;348(9022):224-228.
- 55 - Kakkar AK. Prevention of venous thromboembolism in general surgery.In: Colman RW, Marder VJ, Clowes AW, George JN, Goldhaber SZ, eds. Hemostasis and Thrombosis: Basic Principles and Clinical Practice. 5th ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2006:1361-1367.
- 56 - Motte S, Samama CM, Guay J, Barré J, Borg JY, Rosencher N. Prevention of postoperative venous thromboembolism. Risk assessment and methods of prophylaxis. Can J Anaesth. 2006;53(6)(suppl):S68-S79.
- 1 - Lapostolle F, Surget V, Borron SW, et al. Severe pulmonary embolism associated with air travel. N Engl J Med. 2001;345(11):779-783.
- 64 - Francis CW. Clinical practice. Prophylaxis for thromboembolism in hospitalized medical patients. N Engl J Med. 2007;356(14):1438-1444.
- 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.
- A potentially dangerous state of an increased tendency for blood to coagulate, even within blood vessels. Hypercoagulability can be an inherited condition (e.g., Factor V Leiden mutation) or acquired through circumstance (e.g., cancer).
- The prevention of a disease or pathological condition.
- 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.
- The use of medication or medical devices to prevent the formation of blood clots.
- Reverse Trendelenberg
- A person in the 'Reverse Trendelenberg' position is lying on the back with their feet slightly lower than their head.
- 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.