A client had a new artificial aortic heart valve implanted three days ago and is receiving a heparin IV infusion. The client's activated partial thromboplastin time (aPTT) is 60 seconds, and the international normalized ratio (INR) is 2. The nurse should prepare the client for which change in prescriptions? Reference Range: Activated partial thromboplastin time (aPTT) [1.5 to 2.5 times the control value in seconds.] International normalized ratio (INR) [0.8 to 1.1]

Rationale: A. Replacement of the heparin infusion with warfarin PO daily: Clients with prosthetic heart valves require long-term anticoagulation with warfarin. Since the INR is now therapeutic at 2, the transition from heparin to warfarin is indicated. B. Low molecular weight heparin SUBQ in addition to the heparin infusion: Adding LMWH while the client is already on heparin is unnecessary and increases bleeding risk. LMWH is sometimes used for bridging but not alongside a therapeutic IV heparin infusion. C. Reduction of the heparin infusion and initiation of enteric coated aspirin PO daily: Aspirin is not the standard long-term therapy for mechanical valve replacement. Antiplatelet therapy may sometimes be combined with warfarin, but it does not replace anticoagulation. D. Discontinuing the heparin infusion and initiation of protamine sulfate IV: Protamine sulfate is an antidote for heparin toxicity. Since the aPTT is within therapeutic range (60 seconds), there is no indication of overdose or excessive bleeding requiring reversal.