What is the preferred anticoagulation regimen for an 87-year-old patient with a history of Coronary Artery Bypass Grafting (CABG) x 3 and Aortic Valve Replacement (AVR)?

Anticoagulation Management for an 87-Year-Old Patient with CABG x 3 and AVR

For an 87-year-old patient with history of CABG x 3 and aortic valve replacement (AVR), warfarin with a target INR of 2.5 (range 2.0-3.0) plus low-dose aspirin (75-100 mg daily) is the preferred anticoagulation regimen. 1, 2

Anticoagulation Selection Based on Valve Type

The anticoagulation regimen depends critically on whether the patient received a mechanical or bioprosthetic valve:

For Mechanical AVR:

• Standard regimen: Warfarin with target INR 2.5 (range 2.0-3.0) plus aspirin 75-100 mg daily 1, 2
• If additional risk factors exist (atrial fibrillation, previous thromboembolism, LV dysfunction, or hypercoagulable conditions), increase target to INR 3.0 (range 2.5-3.5) 1
• Older-generation mechanical valves (ball-in-cage or caged disk) require higher intensity anticoagulation with INR 3.0 (range 2.5-3.5) plus aspirin 1

For Bioprosthetic AVR:

• Warfarin with target INR 2.5 (range 2.0-3.0) for the first 3-6 months after valve implantation 1, 2
• After this initial period, transition to lifelong aspirin 75-100 mg daily 1, 2

Special Considerations for Elderly Patients

Given the patient's advanced age (87 years), several factors require special attention:

• Bleeding risk: Elderly patients have increased risk of anticoagulation-related bleeding complications 1, 3
• Medication interactions: More frequent INR monitoring is needed due to potential drug interactions common in elderly patients 1
• Dosing approach: Start with lower warfarin doses (typically 2-5 mg daily) with careful titration based on INR response 4, 3
• Monitoring frequency: Initially monitor INR every few days until stable, then every 2-4 weeks 2

Practical Implementation

1. Initial dosing: Begin with warfarin 2-3 mg daily (lower than standard due to advanced age) 4, 3
2. Titration: Adjust dose based on INR results, targeting the appropriate range based on valve type
3. Monitoring: Check INR after 3-4 days, then twice weekly until stable, then every 2-4 weeks 1
4. Add aspirin: Once INR is stable, add aspirin 75-100 mg daily 1, 2
5. Patient education: Provide detailed information about diet consistency, medication interactions, and bleeding signs

Important Cautions

• DOACs (direct oral anticoagulants) are contraindicated in patients with mechanical heart valves 2
• Avoid triple therapy (dual antiplatelet plus anticoagulant) unless absolutely necessary due to extremely high bleeding risk in elderly patients 1
• For any procedures requiring temporary interruption of anticoagulation, consider bridging therapy with heparin, especially for mechanical valves 2
• INRs >4.0 significantly increase bleeding risk without additional antithrombotic benefit 1, 5

Anticoagulation Clinic Management

Consider referral to a specialized anticoagulation clinic, which has been shown to reduce adverse events and improve outcomes in elderly patients on warfarin therapy 6.