From the Guidelines
The choice between metallic and bioprosthetic valves for aortic valve replacement should be individualized based primarily on patient age, life expectancy, and ability to take anticoagulation, with mechanical valves generally recommended for younger patients and bioprosthetic valves for older patients or those with specific contraindications to anticoagulation. When considering the choice between metallic and bioprosthetic valves, several factors come into play, including valve durability, expected hemodynamics, surgical or interventional risk, the potential need for long-term anticoagulation, and patient values and preferences 1. The decision involves weighing the risk of reintervention for bioprosthetic valve deterioration against the risk of long-term anticoagulation with mechanical valves, which requires lifelong anticoagulation with warfarin and aspirin 1. For patients under 50 years of age, mechanical valves are often preferred due to their superior durability, but this requires careful consideration of the patient's ability to manage lifelong anticoagulation 1. In contrast, bioprosthetic valves are typically preferred for older patients (over 65-70 years) or those with limited life expectancy, as they usually require only temporary anticoagulation post-surgery, followed by aspirin alone 1. The most recent guidelines suggest that for patients aged 50-70, the decision should be individualized, taking into account patient preferences, lifestyle factors, comorbidities, and compliance with medication regimens 1. Ultimately, the choice between metallic and bioprosthetic valves should be a shared decision-making process that accounts for the patient’s values and preferences, with full disclosure of the indications for and risks of anticoagulant therapy and the potential need for and risks associated with valve reintervention 1. Key considerations include the patient's age, life expectancy, ability to take anticoagulation, and personal preferences regarding anticoagulation management versus potential reoperation, as outlined in the 2020 ACC/AHA guideline and the 2021 ESC/EACTS guideline 1. Some of the key evidence supporting these recommendations includes studies on the durability of bioprosthetic valves, the risks of anticoagulation, and the outcomes of patients with mechanical versus bioprosthetic valves 1. For example, a prospective cohort study by Goldstone et al. (2017) found that mechanical prostheses were associated with lower 15-year mortality for patients aged 45-54 years, while a randomized trial by Stassano et al. found that the 10-year risk of bioprosthetic valve failure was significantly increased in patients aged 55-70 years 1. Overall, the decision between metallic and bioprosthetic valves for aortic valve replacement requires careful consideration of multiple factors and should be individualized to each patient's unique needs and preferences.
From the Research
Recommendations for Aortic Valve Replacement
The choice between metallic and biologic valves for aortic replacement depends on various factors, including patient age, lifestyle, and medical history.
- Metallic valves are more durable but require lifelong anticoagulation therapy to prevent blood clots, as seen in the study by 2.
- Biologic valves, on the other hand, have a lower risk of blood clots but may not be as durable, with a higher risk of reoperation, as noted in the study by 3.
Patient Age and Valve Choice
For patients between 45 and 65 years old, the type of biologic valve used does not significantly affect midterm survival or valve-related morbidity, as found in the study by 3.
- However, for patients aged 50 to 70 years, mechanical valves may have a survival advantage compared to bioprostheses, as suggested by the study by 4.
- A more recent study by 5 found that long-term survival was comparable between biological and mechanical prostheses in patients between 50 and 65 years old.
Anticoagulation Therapy
The use of anticoagulation therapy after biologic aortic valve replacement is still a topic of debate, with some studies suggesting that aspirin may be as effective as warfarin in preventing cerebral ischemic events, as seen in the study by 6.
- The American College of Cardiology/American Heart Association and European Society of Cardiology guidelines recommend the use of warfarin for the first three months after biological aortic valve replacement, although the benefits and risks are still unclear, as noted in the study by 6.
Valve-Related Morbidity
The risk of valve-related morbidity, such as stroke, reoperation, and major bleeding, varies between metallic and biologic valves, with mechanical prostheses associated with a higher risk of major bleeding and biologic prostheses associated with a higher risk of reoperation, as found in the study by 5.