Anticoagulation and Antiplatelet Therapy — Written Clinical Reasoning

Model answer — Part A: the warfarin hip replacement

Frame the decision as risk arbitration. His stroke risk off anticoagulation is modest and brief; the surgical bleeding risk of arthroplasty is significant. The evidence base is BRIDGE: in warfarin-treated AF patients, therapeutic-dose LMWH bridging produced no reduction in thromboembolism but significantly more major bleeding — so the plan is interruption WITHOUT bridging ^[1].

The protocol: last warfarin dose 5 days before surgery (day minus 6); INR on the day before or day of surgery, with low-dose oral vitamin K only if the INR remains elevated; no bridging LMWH; prophylactic-dose heparin post-op until full anticoagulation is safe; restart warfarin the evening of surgery or next day if haemostasis is secure (warfarin's slow onset is itself the bridge); full therapeutic effect returns over days ^[1].

If he were on apixaban: apply the PAUSE schedule — hold for about 2 days before a high-bleed-risk procedure (last dose 3 days pre-op, longer only if renal impairment), no bridging, and resume full-dose apixaban at 48–72 hours post-op given the bleeding risk of arthroplasty, using prophylactic dosing in between ^[3].

If the procedure were pacemaker insertion: reverse the logic entirely — BRUISE CONTROL showed continued warfarin through device surgery causes markedly less pocket haematoma than interruption with heparin bridging, so operate on therapeutic warfarin with a pre-procedure INR check ^[2].

Named exceptions to no-bridging earn the final marks: mechanical mitral valve, stroke/TIA or VTE within 3 months, or very high thrombotic risk — decided with haematology, not habit ^[1].