What is the preferred anticoagulant, warfarin or Eliquis (apixaban), for a patient with a bioprosthetic pig valve?

Warfarin vs Eliquis for Bioprosthetic Pig Valve

Warfarin is the only appropriate anticoagulant for patients with bioprosthetic pig valves who require anticoagulation—Eliquis (apixaban) and other direct oral anticoagulants (DOACs) are contraindicated and should not be used. 1, 2

Why DOACs Like Eliquis Are Contraindicated

• The 2020 ACC/AHA guidelines explicitly recommend against using DOACs routinely for bioprosthetic valves, based on harm demonstrated in the GALILEO trial and absence of robust supporting evidence 2
• DOACs have not been adequately studied in patients with bioprosthetic valves and lack FDA approval for this indication 1
• The evidence base for anticoagulation in bioprosthetic valves is built entirely on warfarin (vitamin K antagonist) studies, not DOACs 1

When Warfarin Is Indicated for Bioprosthetic Valves

Early Post-Operative Period (First 3-6 Months)

For mitral position bioprosthetic valves:

• Warfarin with target INR 2.5 (range 2.0-3.0) is recommended for the first 3 months after valve insertion 1
• This can be extended to 6 months in patients at low bleeding risk 1, 2
• The stroke risk in the first postoperative month can be as high as 40 events per 100 patient-years for mitral bioprostheses 1

For aortic position bioprosthetic valves:

• Warfarin with target INR 2.5 (range 2.0-3.0) is reasonable for 3-6 months in patients at low bleeding risk 1, 2
• A large Danish registry demonstrated lower stroke and mortality rates with 6 months of warfarin after bioprosthetic aortic valve replacement, without significantly increased bleeding 1, 2
• The evidence is somewhat weaker than for mitral valves (Grade 2C vs Grade 2C) 1

Long-Term Management (Beyond 3-6 Months)

Warfarin is indicated indefinitely if:

• Atrial fibrillation is present (most common reason for long-term anticoagulation) 1, 2
• History of systemic embolism exists 2
• Evidence of thrombus was found at surgery 2
• Additional risk factors are present: left ventricular dysfunction, hypercoagulable state, or previous thromboembolism 1, 2

For patients WITHOUT these risk factors:

• Low-dose aspirin (75-100 mg daily) is recommended after the initial 3-6 month period, NOT warfarin 1, 2
• Long-term warfarin is not supported by evidence in patients with bioprosthetic valves in normal sinus rhythm without other risk factors 1
• The long-term thromboembolic risk with bioprosthetic valves is low (0.2-2.6% per year), with aortic position having the lowest risk (0.2% per year) 1

Critical Clinical Pitfalls

• Never use Eliquis or any DOAC for bioprosthetic valves—this is based on demonstrated harm in clinical trials 1, 2
• The highest stroke risk occurs in the first 30-180 days after valve implantation, justifying time-limited warfarin therapy 1, 2
• Achieving and maintaining therapeutic INR with warfarin can be challenging: in one registry, 20% of patients failed to reach therapeutic levels, and among those who did, 78% had at least one subtherapeutic INR during follow-up 3
• Patients with supratherapeutic INR values have a seven-fold higher risk of bleeding (26% vs 3%) 3
• If atrial fibrillation develops at any point, this becomes an independent indication for lifelong anticoagulation with warfarin 1, 2