Study Published in JAMA Finds Tissue Valves As Safe As Mechanical Valves in Middle-Aged Patients Over the Long Term

No significant difference in 15-year survival or stroke rates in younger patients who had aortic valve replacement with bioprosthetic valves compared with mechanical valves.

 – September 30, 2014 /Press Release/  –– 

New Icahn School of Medicine at Mount Sinai research findings published in the October 1 issue of JAMA show there was no significant difference in 15-year survival or stroke rates in patients aged between 50 and 69 years who had aortic valve replacement with bioprosthetic valves (made primarily with biological tissue) compared with mechanical valves. The study results show patients in the bioprosthetic valve group had a greater likelihood of reoperation but a lower likelihood of major bleeding.

About 50,000 patients have aortic valve replacement surgery each year in the United States. In elderly patients, bioprosthetic valves pose a low lifetime risk of needing additional surgeries to address structural degeneration and avert many of the complications associated with mechanical valves; bioprosthetic valves are therefore recommended in patients older than 70 years. Less clear is the best prosthesis type for younger patients because they see higher failure rates of bioprosthetic valves.

"Our study findings support the choice of tissue valves in middle-aged patients who need aortic valve replacement," says Joanna Chikwe, MD, Associate Professor in the Department of Cardiovascular Surgery at Icahn School of Medicine at Mount Sinai and the study's lead author. "Our new evidence may help patients who want to avoid the complications and lifestyle limitations associated with mechanical valves."

"This is one of the largest studies to date on the long-term outcomes of treatment of patients with aortic valve replacement," says the study's senior author Natalia Egorova, PhD, MPH, Assistant Professor in the Department of Population Health Science and Policy at Mount Sinai. "The previous prospective studies have been underpowered to detect differences in long-term survival and major morbidity in the younger age group that we studied."

The study's authors used a statewide patient database to evaluate differences in long-term survival, stroke, reoperation, and major bleeding episodes after aortic valve replacement according to the type of valve implanted. The analysis included 4,253 patients aged 50 to 69 years who underwent primary isolated aortic valve replacement using bioprosthetic versus mechanical valves in New York State from 1997 through 2004. Median follow-up time was 10.8 years, with a maximum follow-up of 16.9 years.

"Our study findings show that tissue valves are as safe as mechanical valves in this younger patient group," says Mr. Chiang, the study's first author, who is currently a fourth year medical student in the inaugural class of the combined MD/Master of Science in Clinical Research PORTAL program at Mount Sinai.

Fifteen-year survival was 60.6 percent in the bioprosthesis group compared with 62.1 percent in the mechanical prosthesis group. The cumulative incidence of stroke at 15 years was 7.7 percent for patients who received a bioprosthetic valve, compared with 8.6 percent for those who received a mechanical prosthetic valve. These differences were not statistically significant.

Bioprostheses were associated with a significantly higher rate of aortic valve reoperation than mechanical prostheses: the cumulative incidence of aortic valve reoperation at 15 years was 12.1 percent in the bioprosthesis group and 6.9 percent in the mechanical prosthesis group. Mechanical prostheses were associated with a significantly higher rate of major bleeding at 15 years compared with bioprostheses: 13.0 percent for the mechanical prosthesis group vs. 6.6 percent for the bioprosthesis group.

"These outcomes, together with the well-recognized patient dissatisfaction with the prospect of a lifetime of anticoagulation, may partially explain the increasing use of bioprostheses," the authors write.

Mount Sinai study co-authors are David H. Adams, MD, Professor and Chair of Cardiovascular Surgery for the Mount Sinai Health System, and Shinobu Itagaki, MD, a surgical resident on the Integrated Thoracic Surgery Residency Program; and Alan J. Moskowitz, MD, Professor in the Department of Population Health Science and Policy.

About the Mount Sinai Health System
The Mount Sinai Health System is an integrated health system committed to providing distinguished care, conducting transformative research, and advancing biomedical education. Structured around seven member hospital campuses and a single medical school, the Health System has an extensive ambulatory network and a range of inpatient and outpatient services—from community‐based facilities to tertiary and quaternary care.

The System includes approximately 6,600 primary and specialty care physicians, 12‐minority‐owned free‐standing ambulatory surgery centers, over 45 ambulatory practices throughout the five boroughs of New York City, Westchester, and Long Island, as well as 31 affiliated community health centers. Physicians are affiliated with the Icahn School of Medicine at Mount Sinai, which is ranked among the top 20 medical schools both in National Institutes of Health funding and by U.S. News & World Report.

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