What is Venous Thromboembolism (VTE) and why is it a high risk postoperatively?

From the Guidelines

Venous thromboembolism (VTE) is a high-risk condition postoperatively, and all patients undergoing major elective abdominal or pelvic surgery should receive VTE prophylaxis, unless contraindicated, due to the significant risk of morbidity and mortality associated with VTE. VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE), occurring when blood clots form in veins, typically in the legs (DVT), which can then break off and travel to the lungs (PE) 1. The risk of VTE is increased postoperatively due to several factors that create Virchow's triad: venous stasis, endothelial injury, and hypercoagulability. Surgery often requires immobility, which leads to blood pooling in the veins. Surgical trauma damages blood vessel walls, activating the clotting cascade. Additionally, the inflammatory response to surgery increases blood coagulability. Certain surgeries carry higher risks, particularly orthopedic procedures like hip and knee replacements, major abdominal or pelvic operations, and neurosurgery. Patient-specific risk factors include advanced age, obesity, cancer, previous VTE, hormone therapy, and inherited thrombophilias.

Some key points to consider in the prevention of VTE include:

• Early mobilization
• Mechanical prophylaxis (compression stockings, intermittent pneumatic compression devices)
• Pharmacological prophylaxis with anticoagulants like low molecular weight heparin (LMWH) or unfractionated heparin (UFH)
• The use of extended-duration thromboprophylaxis for 30 days post-surgery using LMWH or a direct oral anticoagulant (DOAC) to decrease the burden of VTE in high-risk patients 1
• The incidence of post-discharge VTE is low, but extended prophylaxis may be beneficial in high-risk patients, such as those with restricted mobility, obesity, or a history of VTE 1

The most recent and highest quality study recommends extended-duration thromboprophylaxis for all high-risk patients undergoing major abdominopelvic surgery, with a significant reduction in the risk of overall VTE and symptomatic VTE 1. Therefore, extended-duration thromboprophylaxis should be considered for all high-risk patients undergoing major abdominopelvic surgery, unless contraindicated, to reduce the risk of VTE and its associated morbidity and mortality.

From the FDA Drug Label

1.5 Prophylaxis of Deep Vein Thrombosis Following Hip or Knee Replacement Surgery XARELTO is indicated for the prophylaxis of DVT, which may lead to PE in adult patients undergoing knee or hip replacement surgery.

1.6 Prophylaxis of Venous Thromboembolism in Acutely Ill Medical Patients at Risk for Thromboembolic Complications Not at High Risk of Bleeding XARELTO is indicated for the prophylaxis of venous thromboembolism (VTE) and VTE related death during hospitalization and post hospital discharge in adult patients admitted for an acute medical illness who are at risk for thromboembolic complications due to moderate or severe restricted mobility and other risk factors for VTE and not at high risk of bleeding

Venous Thromboembolism (VTE) is a condition where a blood clot forms in the deep veins of the body, which can lead to Pulmonary Embolism (PE). VTE is a high risk postoperatively due to factors such as:

• Immobilization: Prolonged bed rest or restricted mobility can increase the risk of blood clots forming in the deep veins.
• Surgery: Major surgeries, especially those involving the hip or knee, can increase the risk of VTE.
• Other risk factors: Such as age, obesity, and history of previous VTE. The FDA drug label for rivaroxaban 2 indicates that it is used for the prophylaxis of DVT, which may lead to PE, in adult patients undergoing knee or hip replacement surgery, and for the prophylaxis of VTE in acutely ill medical patients at risk for thromboembolic complications.

From the Research

Definition of Venous Thromboembolism (VTE)

• Venous Thromboembolism (VTE) is a preventable cause of postoperative morbidity and mortality 3
• It is a common complication of surgical procedures, determined by the combination of individual predisposing factors and the specific type of surgery 4

Risk Factors for VTE

• Patient characteristics such as history of VTE, Factor V Leiden disorder, and use of general anesthesia increase the risk of postoperative VTE 5
• The type of surgery, such as orthopedic surgery, also plays a significant role in determining the risk of VTE 4, 5
• Other risk factors include patient- and procedure-specific factors, which can be estimated using validated risk-assessment models such as the Caprini score 3

High Risk Postoperatively

• VTE is a high risk postoperatively due to the combination of patient and surgical factors, which can lead to a hypercoagulable state 4, 6
• The risk of VTE is highest in the first week after surgery, with over 90% of pulmonary embolisms (PEs) and 33.3% to 75% of deep vein thromboses (DVTs) diagnosed during this period 5
• The use of prophylactic strategies, such as mechanical and pharmacological methods, can reduce the risk of VTE postoperatively 3, 4, 6

Prophylaxis Strategies

• Prophylaxis with mechanical and pharmacological methods has been shown to be effective and safe in most types of surgery 4
• The use of low-dose unfractionated heparin, low-molecular-weight heparin, fondaparinux, and warfarin are recommended for pharmacological prophylaxis 4, 6, 7
• Mechanical prophylaxis with graduated compression stockings and intermittent pneumatic compression is also recommended as an alternative or in combination with pharmacological prophylaxis 6