A 70-year-old man with mechanical aortic valve prosthesis is on warfarin (INR 2.5–3.5). He needs elective colectomy. What is the MOST appropriate perioperative anticoagulation strategy?
- A Stop warfarin 5 days preoperatively; no heparin bridging required for tissue valve
- B Continue warfarin throughout — target INR 2.0 during surgery is acceptable for colectomy
- C Stop warfarin 5 days preoperatively; bridge with therapeutic low-molecular weight heparin given the high thromboembolic risk of mechanical valve ✓
- D Switch permanently to DOACs (rivaroxaban) preoperatively as they do not require bridging
Explanation
Mechanical heart valves carry high thromboembolic risk (especially aortic mechanical valves, higher for mitral) and require warfarin bridging when anticoagulation must be interrupted. The BRIDGE trial (2015) showed no benefit of LMWH bridging in AF patients but specifically EXCLUDED patients with mechanical valves, who remain an indication for bridging per ACC/AHA guidelines. Strategy: stop warfarin 5 days preoperatively; start therapeutic LMWH (enoxaparin 1 mg/kg BD or UFH) when INR <2.0; hold LMWH 24 h before surgery; restart post-surgery when haemostasis secured; resume warfarin. DOACs are contraindicated with mechanical valves.
Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.