What are the considerations for using a mechanical valve in heart valve replacement?

From the Guidelines

Mechanical heart valves are a suitable option for heart valve replacement, but their use requires careful consideration of the need for lifelong anticoagulation therapy, typically with a vitamin K antagonist (VKA) and a target INR of 2.0-3.0, to prevent thromboembolic events 1. When considering the use of a mechanical valve, several factors must be taken into account, including the patient's age, lifestyle, and ability to manage anticoagulation therapy.

• The decision to use a mechanical valve should be based on a shared decision-making process between the patient and the healthcare provider, taking into account the patient's values and preferences 1.
• Mechanical valves are generally preferred for younger patients (under 50-60 years) due to their exceptional durability, which can last 20-30 years or more, and avoids the need for future reoperations 1.
• However, mechanical valves are contraindicated in patients who cannot take anticoagulants, women planning pregnancy, and those with lifestyle concerns about bleeding risks or monitoring requirements.
• The target INR range for patients with mechanical valves is typically between 2.0 and 3.0, with a goal of reducing the risk of thromboembolic events while minimizing the risk of bleeding 1.
• Regular blood monitoring is necessary to ensure that the patient's INR remains within the target range, and patients must be educated on the importance of adhering to their anticoagulation regimen.
• The choice of valve type, either mechanical or bioprosthetic, should be individualized based on the patient's specific needs and circumstances, and should take into account factors such as the patient's age, lifestyle, and medical history 1.

From the Research

Considerations for Mechanical Valve Replacement

• The choice of prosthesis type in patients with valvular heart disease should always be individualised, weighing the concerns surrounding durability of bioprosthetic valves compared with mechanical valves and the need for lifelong anticoagulation required with mechanical valves 2.
• Mechanical valves are typically chosen for young patients undergoing mitral valve replacement due to their durability, but bioprosthetic valves may have the benefit of valve-in-valve transcatheter valve replacement when valve failure occurs 3.
• Guidelines recommend that patients under the age of 60 would benefit from a mechanical valve, and those over 70 would benefit from a bioprosthetic valve 2.

Anticoagulation Management

• Anticoagulation regimens vary according to surgeon, nature of the valve (mechanical or biological), its position, and other risk factors for stroke 4.
• For mechanical heart valves, anticoagulation with Warfarin at an INR range 2-3 for patients with a bileaflet mechanical valve in the aortic position is recommended, while an INR of 2.5-3.5 is recommended for valves in the mitral position 4.
• Alternative anticoagulation therapies, such as enoxaparin, may be considered for patients who do not tolerate or who fail warfarin 5.
• Combined low-dose aspirin and warfarin therapy may be associated with a greater reduction in thromboembolism events than warfarin therapy alone, without an increase in the rate of major bleeding or mortality 6.

Outcomes and Complications

• Mechanical valve replacement may be associated with a lower reoperation rate and longer estimated survival compared to bioprosthetic valve replacement in patients under 65 years old 3.
• The incidence of bleeding and stroke or embolic events between mechanical and bioprosthetic valve replacement groups may be similar 3.
• Thromboembolism related to a mechanical heart valve is a major complication after surgical valve replacement, and alternative anticoagulation therapies may be necessary in some cases 5.