Mechanical heart valves provide better long-term survival for patients ages 50 to 70

Mechanical heart valves provide better long-term survival for patients ages 50 to 70

Patients aged between 50 and 70 who had a mechanical heart valve replacement had better long-term survival compared to those with a biological valve, new research led by the University of Bristol. The study is published in theEuropean Journal of Cardiothoracic Surgery.

Over the past two decades, the use of biological over mechanical heart valve replacement has increased. While short-term clinical results are known as the same long-term results are still debated.

Existing guidelines support the use of mechanical valves made from synthetic materials in patients younger than 50 years, while biological valves made from animal tissue are preferred for those older than 65 or 70 years. The guidelines leave the decision up to surgeons and patients ages 50 to 70.

The research team wanted to find out the clinical outcomes for patients aged between 50 and 70 years of elective and urgent heart valve replacement at the Bristol Heart Institute (BHI) over a period of 27 years [1996 to 2023].

The researchers also sought to examine trends, early outcomes and long-term survival rates, the incidence of repeat valve interventions, and patient prosthesis mismatch (PPM).

A total of 1,708 (61% male) patients with a mean age of 63 years were included, with 1,191 (69.7%) receiving biologic valve replacement.

The research found that there were no short-term differences when patients receiving biological and mechanical valves were compared. However, patients who received mechanical valves had better long-term survival up to 13 years after surgery.

Patients with 19 mm biological valves (a fairly small valve commonly used in women) had worse long-term survival. Patients with a mechanical size of 21 mm had better survival compared to biological valves of size 19 and 21 mm. The study confirmed that severe PPM is a significant risk factor for poor long-term survival.

Gianni Angelini, BHF Professor of Cardiac Surgery at Bristol Medical School: Translational Health Sciences (THS), Director of the Bristol Heart Institute and corresponding author, said:"Our study has implications for decision-making in surgical valve replacement in patients between the ages of 50 and 70. The evidence of better long-term survival in patients receiving a mechanical heart valve suggests that the current trend favoring biological valves in this age group should be urgently repaired. The survival benefit is particularly clear in smaller valves." “

The research team recommends evaluating the long-term benefits associated with mechanical valves, particularly in smaller sizes, although long-term blood thinners are not needed with biological valves.

Study limitations

The single-institution design, retrospective data collection, and lack of randomization make the study open to bias. The lack of echocardiographic information could potentially underestimate the incidence of structural valve failure. Regarding repeated valve interventions, only patients who underwent RE-do surgical aortic valve valve replacement or valve transcatheter aortic valve implantation (TAVI) at BHI were included.

Since BHI is a supra-regional center, it is very unlikely that many patients have undergone reintervention at other institutions. The cause of death (cardiovascular/non-cardiovascular) was not available.

Sources: