Reference: Dunn AS, Spyropoulos AC, Turpie AG. Bridging therapy in patients on long-term oral anticoagulants who require surgery: the Prospective Peri-operative Enoxaparin Cohort Trial (PROSPECT). Journal of Thrombosis and Haemostasis. 2007 Nov;5(11):2211-2218.
Summary: Due to limited data on the incidence of peri-operative thromboemobolic and bleeding during bridge therapy, there is no agreement on optimal peri-operative management of patients on oral anticoagulants (OACs). Dunn et al sought to “examine the incidence of major bleeding of a peri-operative strategy using once-daily therapeutic-dose enoxaparin administered primarily at home, and the effect, if any, of the extensiveness of the procedure on the risk of bleeding during bridge therapy” (p.2211-2212).
The study involved 24 sites in North America between January 2002 and August 2003. The figure below shows the study’s peri-operative management protocol (p.2212): 
Safety outcomes:
- Incidence of major bleeding while on enoxaparin or in the 24 hours following cessation of enoxaparin treatment
- Occurred in 3.5% (95% CI: 1.6-6.5)
- Invasive procedures: 1.4%
- Minor surgery: 0%
- Major surgery: 27.5%
- Rate of minor bleeding while on enoxaparin, or within 24 hours of discontinuation
- Occurred in 108 patients (41.5%, 95% CI:35.7-47.6)
- Invasive procedures: 44.6%
- Minor surgery: 47.2%
- Major surgery: 20.0%
Efficacy outcomes:
- Incidence of arterial thromboembolic events for patients with afib
- 4 events out of 176 patients (2.3%, 95% CI: 0.6-5.7)
- 2 TIAs, 0 strokes, 2 patients had peripheral arterial thromboembolic events
- Incidence of venous thromboembolic events for patients with a history of DVT.
- 1 event out of 96 patients (1.0%, 95% CI: 0.03-5.7)
- None fatal
Bleeding risk is high when bridging therapy is done peri-operatively in major surgery. In this study, there were 8 instances of major bleeding among 40 total patients in major surgery. Out of 220 invasive procedures or minor surgery, there was only 1 major bleeding event.
Surgical Focus 