Anticoagulation Management for Mechanical Aortic Valves

Introduction to Mechanical Aortic Valve Anticoagulation

The American College of Cardiology recommends that all patients with mechanical aortic valves require lifelong anticoagulation with warfarin, which is a non-negotiable, Class I recommendation with no acceptable alternatives in routine clinical practice 1, 2, 3
Mechanical valves create inherently thrombogenic conditions due to abnormal flow patterns, zones of low flow within valve components, and high-shear stress that activates platelets, leading to valve thrombosis and embolic events without anticoagulation 3
The risk without warfarin is prohibitive: thromboembolic complications occur at considerably higher rates in patients not receiving warfarin therapy, making it unsafe to withhold anticoagulation 1

For bileaflet or current-generation single tilting disc valves in the aortic position without additional risk factors, maintain INR at 2.5 (range 2.0-3.0) 1, 2, 3
For patients with additional thromboembolic risk factors, such as previous thromboembolism or hypercoagulable state, increase the target INR to 3.0 (range 2.5-3.5) 1, 3

Mechanical valves require lifelong warfarin with no option to discontinue 1, 2, 3
Bioprosthetic (tissue) valves only require warfarin for 3-6 months post-implantation, then can transition to aspirin alone 4

Initiate bridging anticoagulation with heparin or LMWH early after surgery until INR reaches therapeutic range 3
Anticoagulation clinic management results in lower complication rates compared to standard care; home INR monitoring is acceptable for motivated patients 3
Specify a single INR target value rather than just a range, as INR fluctuations are associated with increased complications 3