Anticoagulation Management for Mechanical Heart Valves

Introduction to Anticoagulation Targets

The American College of Cardiology recommends a target INR of 2.5 (range 2.0-3.0) for mechanical aortic valves without risk factors, and a target INR of 3.0 (range 2.5-3.5) for mechanical mitral valves or aortic valves with risk factors 1, 2, 3

For low-risk patients with mechanical aortic valves, the target INR is 2.5 (range 2.0-3.0), and aspirin 75-100 mg daily should be added to warfarin therapy 1, 2, 3
For high-risk patients with mechanical aortic valves, the target INR is 3.0 (range 2.5-3.5), due to the presence of risk factors such as atrial fibrillation, previous thromboembolism, left ventricular dysfunction, hypercoagulable conditions, or older-generation mechanical valves 1, 2, 3

The target INR for all mechanical mitral valve replacements is 3.0 (range 2.5-3.5), regardless of risk factors, and aspirin 75-100 mg daily should be added to warfarin therapy 1, 2, 3

If a stroke or systemic embolism occurs while the patient is on therapeutic anticoagulation, the INR goal should be increased to 3.0 (range 2.5-3.5) for mechanical aortic valves, or to 4.0 (range 3.5-4.5) for mechanical mitral valves, or low-dose aspirin 75-100 mg daily should be added if not already prescribed 1

Direct oral anticoagulants (DOACs) should not be used in patients with mechanical heart valves, as dabigatran is contraindicated and anti-Xa DOACs have not been assessed 1
A single INR target value should be specified, rather than just a range, to reduce the likelihood of patients consistently running at the upper or lower boundary 2
INR fluctuations increase complications, and patients should strive for consistent INR values within the target range 2
Anticoagulation clinics with dedicated pharmacists or nurses result in lower complication rates than standard care 2
Low-dose aspirin (75-100 mg daily) is recommended in addition to warfarin for all mechanical valve patients, but the addition of aspirin should be balanced against increased bleeding risk 1, 3