Is there data or rationale for overlapping warfarin with LMWH, UFH, or fondaparinux for VTE prophylaxis post hip or knee orthopedic surgery?
Current ACCP guidelines recommend prophylaxis with LMWH, fondaparinux, or adjusted dose vitamin K antagonists (VKA) for total hip and knee arthroplasty; UFH is not recommended in these populations as it has been found less efficacious than the aforementioned strategies. VKA dosing should begin the day before or the day of surgery and should achieve a target INR 2.0-3.0 within 72 hours post-op. If the INR is not realized at 72 hours, full dose anticoagulation with LMWH or UFH should be used until the therapeutic target is reached. This is the protocol that provides level 1A evidence in support of vitamin K antagonists in this population. Some practitioners have started prophylactic LMWH or fondaparinux post-op at the same time as vitamin K antagonists until the INR goal is reached. To my knowledge, there are no randomized controlled studies comparing this approach to standard evidence-based recommendations. One would hypothesize that this would provide better prophylaxis than traditiona