Anticoagulation in Prosthetic (Artificial) Heart Valves
Anticoagulation in Prosthetic (Artificial) Heart Valves
(Based on ESC/EACTS Guidelines 2021 and preliminary 2025 update highlights, ACC/AHA 2020 Guidelines, and Recent Reviews 2024)
Keynotes:
1-Mechanical Valves (Surgical)
• Warfarin only — required lifelong for all mechanical valves.
• DOACs are contraindicated (not allowed).
• Target INR:
• Aortic valve → 2.5 (no risk factors) / 3.0 (with risk factors)
• Mitral valve → 3.0 (higher thrombotic risk)
Why Warfarin only?
• Mechanical valves are made of metal or carbon surfaces that directly contact blood and strongly activate clotting.
• Warfarin blocks several key clotting factors (II, VII, IX, X), giving broad protection against valve thrombosis and embolic stroke.
• DOACs (dabigatran, rivaroxaban, apixaban, edoxaban) inhibit only one target (thrombin or Xa) and were unsafe in the RE-ALIGN trial (NEJM 2013), showing higher thrombosis, stroke, and bleeding.
• Therefore, DOACs are Class III – Harm in all guidelines; they must not be used for mechanical valves.
2-Bioprosthetic Valves (Surgical Tissue Valves)
• Warfarin (INR ≈ 2.5) for 3–6 months, then switch to Aspirin only.
• If bleeding risk is high → Aspirin alone from the start is acceptable.
• After 6 months → Aspirin lifelong.
• DOACs may be used only if the patient has another indication (e.g., atrial fibrillation), but not routinely.
3-Transcatheter valves (TAVR / TMVR / TTVR) cause less procedural trauma than surgical tissue valves:
• Aspirin only (Single Antiplatelet Therapy) is now preferred (Class IIa ,Level of Evidence)
• Short DAPT (Aspirin + Clopidogrel for ≈ 3 months) may be used in high-thrombotic-risk cases(Class IIb=optional)
•Warfarin or DOACs — Class IIb, and usually used if another condition requires them (e.g., atrial fibrillation, LV thrombus).
Summary Statement :
For Transcatheter Valves, Aspirin (SAPT) remains the standard (Class IIa).
Short DAPT is optional (Class IIb).
Oral anticoagulation (Warfarin / DOAC) is Class I if another indication exists, and Class IIb if considered without one.
4-If the patient has Atrial Fibrillation or another clear indication for anticoagulation
• Use Warfarin or a DOAC if the valve is bioprosthetic (not mechanical).
• If the valve is mechanical, always Warfarin — never DOACs.
5-Bridging Therapy (during surgery/procedures):
• Major surgery → interrupt VKA and bridge with heparin.
• UFH (intravenous) preferred for predictable effect; LMWH acceptable if monitored (anti-Xa 0.5–1.0 U/mL).
• Fondaparinux should not be used (Class III).
Summary:
U.S. guidelines (ACC/AHA 2020) limit bridging to mitral or high-risk cases,
while European guidelines (ESC 2021) recommend bridging for all mechanical valves.
Key Takeaway :
• Mechanical valve → Warfarin lifelong (only proven safe).
• Bioprosthetic surgical valve → short-term Warfarin or Aspirin, then Aspirin lifelong.
• Transcatheter valve → Aspirin (± short DAPT).
• DOACs → only for other indications, and never for mechanical valves.
