Mechanical Heart Valve Replacements Have Better Long-Term Survival, Study Finds

Over the past two decades, there has been a shift towards the use of biological heart valves rather than mechanical ones. While short-term clinical outcomes for both types of valves are generally considered comparable, the long-term outcomes remain a subject of ongoing debate. Current guidelines recommend mechanical valves made from synthetic materials for patients under 50 years old, while biological valves, which are made from animal tissue, are preferred for individuals over the age of 65 or 70. For patients aged between 50 and 70, the decision is typically left to the discretion of both surgeons and patients. New research, however, suggests that patients aged 50 to 70 who receive a mechanical heart valve replacement may experience better long-term survival than those with a biological valve.

The study, led by the University of Bristol (Bristol, UK), aimed to assess the clinical outcomes for patients aged 50 to 70 who underwent elective and urgent heart valve replacement at the Bristol Heart Institute (BHI) over a 27-year period (1996 to 2023). The researchers focused on trends, early outcomes, long-term survival rates, the incidence of repeat valve interventions, and patient prosthesis mismatch (PPM). The study included 1,708 patients, with 61% male and an average age of 63 years, of whom 1,191 (69.7%) received a biological valve replacement.

The findings, published in European Journal of Cardio-Thoracic Surgery, revealed that there were no significant differences in the short-term outcomes between patients receiving biological and mechanical valves. However, patients with mechanical valves had better long-term survival, up to 13 years post-surgery. Notably, patients who received a 19 mm biological valve (a smaller valve often used in females) had the poorest long-term survival. In contrast, patients with a 21 mm mechanical valve experienced better survival outcomes than those with either a 19 mm or 21 mm biological valve. The study also highlighted that severe PPM is a major risk factor for poor long-term survival. The research team advises further evaluation of the long-term benefits of mechanical valves, particularly in smaller sizes, despite the advantage of biological valves in eliminating the need for long-term blood thinners.

“Our study has implications for decision-making in surgical heart valve replacements for patients aged between 50 and 70 years old,” said Gianni Angelini, BHF Professor of Cardiac Surgery at the Bristol Medical School. “The evidence supporting better long-term survival in patients receiving a mechanical heart valve suggests the current trend favoring biological valves in this age bracket should be urgently reconsidered. The survival benefit is especially clear in smaller sized valves.”