For general and abdominal-pelvic surgery patients at very low low risk for VTE, no specific pharmacologic (Grade 1B) or mechanical (Grade 2C) prophylaxis other than early ambulation is recommended

For patients at low risk of VTE after abdominal-pelvic surgery or cardiac surgery with an uncomplicated course, mechanical prophylaxis, preferably with IPC, over no prophylaxis is suggested (Grade 2C)

For patients at moderate VTE risk after general, abdominal-pelvic, or thoracic surgery, or cardiac surgery with a prolonged course not at high risk for major bleeding complications, LMWH or LDUH (Grade 2B), or mechanical prophylaxis, preferably with IPC (Grade 2C), is suggested over no prophylaxis

For patients at moderate risk for VTE after general, abdominal-pelvic surgery, thoracic surgery, or cardiac surgery who are at high risk for major bleeding complications or those in whom the consequences of bleeding are thought to be particularly severe, mechanical prophylaxis, preferably with IPC, is suggested over no prophylaxis (Grade 2C)

Surgical populations excluding orthopedics

For patients at high risk for VTE after general, abdominal-pelvic, and thoracic surgery who are not at high risk for major bleeding complications, pharmacologic prophylaxis with LMWH (Grade 1B) or LDUH (Grade 1B) is suggested over no prophylaxis. Combination with graduated compression stockings or IPC is also suggested (Grade 2C)

For high-VTE-risk general, abdominal-pelvic, and thoracic surgery patients who are at high risk for major bleeding complications or those in whom the consequences of bleeding are thought to be particularly severe, the use of mechanical prophylaxis, preferably with IPC, is suggested over no prophylaxis until the risk of bleeding diminishes and pharmacologic prophylaxis may be initiated (Grade 2C)

For high-VTE-risk patients undergoing abdominal or pelvic surgery for cancer who are not otherwise at high risk for major bleeding complications, extended-duration pharmacologic prophylaxis (4 weeks) with LMWH is recommended over shorter-duration prophylaxis (Grade 18)

For general and abdominal-pelvic surgery patients at high risk for VTE in whom both LMWH and LDUH are contraindicated or unavailable and who are not at high risk for major bleeding complications, low-dose aspirin (Grade 2C), fondaparinux (Grade 2C), or

mechanical prophylaxis, preferably with IPC (Grade 2C), is suggested over no prophylaxis

For general and abdominal-pelvic surgery patients, an inferior vena cava (IVC) filter is not recommended for primary VTE prevention (Grade 2C)