A recent study comparing mechanical prosthetic versus bioprosthetic mitral valves in patients who were 50 to 69 years old and undergoing mitral valve replacement found no significant differences in survival after 15 years. However, there were differences concerning the risk for reoperation, stroke and bleeding. The results were published in JAMA‘s April 14 issue.
In individuals suffering with severe, symptomatic mitral valve disease that are also ineligible for surgical repair, a mitral valve replacement can reduce symptoms and significantly improve survival chances. Bioprosthetic valves are primarily made of tissue and are highly recommended for those older than 70 years in whom the probability of needing to be reoperated on due to valve degeneration is low. In non elderly patients in need for valve replacement, it is harder to decide between bioprosthetic and mechanical prosthetic valves, as long-term survival and further outcomes are not well defined at the outset of diagnosis.
Joanna Chikwe from the Icahn School of Medicine at Mount Sinai in New York and fellow researchers compared long-term survival, reoperation, stroke and bleeding events after bioprosthetic versus mechanical prosthetic mitral valve replacement; the study enrolled 3,433 patients (aged between 50 and 69 years) that had mitral valve replacement in New York State hospitals within the period of 1997 to 2007 and patients were followed up for 8.2 years on average.
According to researchers, there was no difference in long-term survival between the mechanical ( 57.5 percent of 15-year survival) and the bioprosthetic replacement (59.9 percent of 15-year survival). Further, the cumulative incidence of stroke at 15 years after having mitral valve replacement was significantly higher in the mechanical group compared with the bioprosthesis group (14.0 percent versus 6.8 percent); the same happened on the cumulative incidence of bleeding events (14.9 percent vs. 9.0 percent). Further, the cumulative incidence of mitral valve reoperation at 15 years was much lower in the mechanical prosthesis group (5.0 percent) compared with the bioprosthesis group (11.1 percent).
“Consensus guidelines have increasingly emphasized patient preference in preoperative decision making. Quality-of-life surveys indicate that many patients view the distant possibility of reoperation as a reasonable trade-off for freedom from lifelong anticoagulation, reduced quality of life, and poorer perceived health status associated with mechanical prosthetic valves. Our data strongly suggest that the incremental risks of stroke and bleeding associated with mechanical prosthetic valve replacement should also be a major consideration in any discussion of prosthesis choice,” explained the researchers, pointing out that bioprosthetic mitral valve replacement as a good alternative for patients 50 to 69 years of age.