Mechanical Heart Valve: Overview and Considerations

Introduction

A mechanical heart valve is an artificial device implanted in the heart to replace a malfunctioning natural valve. It is typically used in patients with severe valve disease, such as aortic stenosis, mitral regurgitation, or congenital heart defects. These valves are designed to last a lifetime but require lifelong anticoagulation therapy to prevent blood clots.

Types of Mechanical Heart Valves

There are two main types: 1. Bileaflet Valves – Consist of two semicircular discs that open and close. (e.g., St. Jude valve) 2. Tilting Disc Valves – Feature a single disc that tilts to allow blood flow. (e.g., Medtronic-Hall valve)

Advantages and Disadvantages

Advantages:

✅ Durability: Mechanical valves last 20+ years, unlike biological valves that may require replacement after 10-15 years. ✅ Consistent Function: They provide strong, predictable hemodynamics (blood flow).

Disadvantages:

⚠️ Need for Lifelong Anticoagulation: Patients must take warfarin or direct oral anticoagulants (DOACs) to prevent blood clot formation. ⚠️ Risk of Bleeding: Anticoagulation increases the risk of bleeding complications. ⚠️ Audible Clicking Sound: Some patients can hear the valve opening and closing.

Anticoagulation Therapy and Monitoring

Patients with mechanical valves require close INR (International Normalized Ratio) monitoring: - Target INR for aortic valve: 2.0 - 3.0 - Target INR for mitral valve: 2.5 - 3.5 - Patients may also be prescribed aspirin in certain cases.

Risk Factors and Comorbidities

• Atrial fibrillation increases clot risk and requires stricter INR control.
• Diabetes and hypertension can complicate anticoagulation management.
• Pregnancy increases risks; warfarin can harm the fetus, necessitating special management.

Conclusion

Mechanical heart valves offer a durable solution for valve replacement but require lifelong commitment to anticoagulation and regular clinical follow-ups. Patients must work closely with their cardiologists to maintain proper INR levels and prevent complications.

Source recommendations

1. American Heart Association (AHA)/American College of Cardiology (ACC) Guidelines for the Management of Patients with Valvular Heart Disease

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000923
2. https://pubmed.ncbi.nlm.nih.gov/9809971/
3. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2024/03/13/18/13/2024-acc-aha-clinical-performance-valvular
4. https://pubmed.ncbi.nlm.nih.gov/33332149/
5. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2020/12/16/21/58/2020-ACC-AHA-VHD-GL-Pt-1-GL-VHD

2. European Society of Cardiology (ESC) Guidelines for the Management of Valvular Heart Disease

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Valvular-Heart-Disease-Guidelines
2. https://academic.oup.com/eurheartj/article/43/7/561/6358470
3. https://pubmed.ncbi.nlm.nih.gov/34453165/
4. https://academic.oup.com/eurheartj/article/38/36/2739/4095039
5. https://eurointervention.pcronline.com/article/2021-esc-eacts-guidelines-for-the-management-of-valvular-heart-disease