Tissue-Based Heart Valves Better for the Middle-Aged

Patients between 40 and 70 years of age who undergo aortic valve replacement (AVR) may fare better with tissue-based valves rather than metal-based ones, according to a new study.

Researchers at the University of Sydney (Australia; sydney.edu.au) and Royal Prince Alfred Hospital (Sydney, NSW, Australia) conducted a database search and identified 13 studies comparing mechanical and bioprosthetic valves in AVR patients aged 40 to 70 years. The results revealed that 15-years post-surgery, no difference was found in survival, stroke rate, or rate of endocarditis among patients with either valve; however, each patient group developed a different set of complications.

Patients with bioprosthetic valves were twice as likely as mechanical valve patients to need re-operation due to worn-out valves, while patients with mechanical valves were twice as likely to experience a major bleeding event or a blood clot. Because patients with major bleeding had a significant increase of death compared to those needing reoperation, the researchers concluded that bioprosthetic valves should strongly be considered for patients in this age group, though valve choice should be individualized for each patient. The study was published on January 12, 2016, in the Annals of Thoracic Surgery.

“We combined the best available evidence comparing mechanical valves versus bioprosthetic valves to determine the risks and benefits to patients following surgery, depending on the type of valve they received,” said lead author James Wu, BMusStudies, of the University of Sydney. “We hope that our results can give future patients needing AVR more information to help them choose the appropriate replacement valve for their condition.”

“This is a complex decision that requires up-to-date evidence. There are options to reduce the bleeding risk of mechanical valves, so, ideally, a discussion with both the surgeon and cardiologist is warranted to take into account an individual's circumstances,” concluded senior author Paul Bannon, MBBS, PhD.

Mechanical valves are the most long-lasting type of replacement valve, but patients will usually require blood thinners to stop clots from forming, as they can lodge in valve flaps or hinges which can cause a malfunction or form emboli. Bioprosthetic tissue can last 10–20 years, but usually do not require long-term use of medication. On the other hand, a young person with a bioprosthetic valve replacement, the need for additional surgery or another valve replacement later in life is highly likely.

Related Links:
University of Sydney
Royal Prince Alfred Hospital