What is the goal International Normalized Ratio (INR) for a patient with a St Jude (mechanical) aortic valve?

Goal INR for St Jude Mechanical Aortic Valve

For a St Jude mechanical aortic valve without additional risk factors, target an INR of 2.5 (range 2.0-3.0), but increase to an INR of 3.0 (range 2.5-3.5) if the patient has atrial fibrillation, prior thromboembolism, hypercoagulable state, or severe left ventricular dysfunction. 1

Standard Risk Patients (No Additional Risk Factors)

Target INR: 2.5 (range 2.0-3.0) 1, 2

This recommendation applies to patients with:

• St Jude bileaflet mechanical valve in the aortic position 1
• Normal sinus rhythm 1
• Normal left atrial size 1
• No history of thromboembolism 1

The 2020 ACC/AHA guidelines emphasize that this moderate-intensity anticoagulation provides a reasonable balance between thromboembolism risk (0.53% per patient-year) and bleeding complications, with randomized trials showing no difference in embolic events but significantly reduced bleeding compared to higher INR targets (3.0-4.5). 1

The FDA warfarin label specifically states that for St Jude Medical bileaflet valves in the aortic position, a target INR of 2.5 (range 2.0-3.0) is recommended. 2

High Risk Patients (With Additional Risk Factors)

Target INR: 3.0 (range 2.5-3.5) 1

Increase the INR target if any of the following risk factors are present:

• Atrial fibrillation 1
• Previous thromboembolism 1, 3
• Hypercoagulable state 1
• Severe left ventricular dysfunction 1
• Older-generation prosthesis (ball-in-cage, caged disk) 1

The 2014 AHA/ACC guidelines note that patients with these risk factors require higher-intensity anticoagulation to prevent thromboembolic complications, which are more frequent in this population. 1

Adjunctive Aspirin Therapy

Add low-dose aspirin 75-100 mg daily to warfarin therapy 1, 3

• The addition of aspirin to warfarin reduces major embolism or death from 8.5% to 1.9% per year (P<0.001) and stroke from 4.2% to 1.3% per year (P<0.027). 1
• This combination increases minor bleeding (epistaxis, bruising, hematuria) but does not significantly increase major bleeding risk (8.5% vs 6.6%, P=0.43). 1
• The FDA warfarin label recommends aspirin 75-100 mg/day in combination with warfarin for mechanical valves. 2

Critical Management Principles

Specify a single INR target rather than just a range 1

• Targeting a specific value (2.5 or 3.0) reduces the likelihood of patients consistently running near the upper or lower boundary of the acceptable range. 1
• INR fluctuations are associated with increased complications in prosthetic valve patients. 1

Avoid INR >4.0 1

• Adverse events increase significantly when INR exceeds 4.0 in mechanical aortic valve patients. 1
• INR >4.0 provides no additional therapeutic benefit and substantially increases bleeding risk. 2

Common Pitfalls

Do not use DOACs 3

• Direct thrombin inhibitors (dabigatran) are contraindicated in mechanical valve patients. 3
• Anti-Xa direct oral anticoagulants have not been assessed and are not recommended. 3

Patient compliance challenges with higher INR goals 1, 3

• Patients with target INR 2.0-3.5 achieve therapeutic range 74.5% of the time. 1, 3
• Patients with target INR 3.0-4.5 achieve therapeutic range only 44.5% of the time. 1, 3

Bridging anticoagulation perioperatively 1

• Bridging is recommended during periods when INR is subtherapeutic. 1
• No bridging is needed for routine therapeutic anticoagulation maintenance. 1

Management After Breakthrough Events

If stroke or systemic embolism occurs despite therapeutic INR:

• Increase INR goal from 2.5 (range 2.0-3.0) to 3.0 (range 2.5-3.5) 3
• Add aspirin 75-100 mg daily if not already prescribed, after assessing bleeding risk 3