Two-Year Data Suggest Added Health Risks Of Combining Mitral-Valve Repair To Bypass Surgery With Little Benefit

Lack of Clear Benefit May Signal Major Change in Treatment Algorithm

News provided by

Apr 03, 2016, 04:38 ET

NEW YORK, April 3, 2016 /PRNewswire-USNewswire/ -- Just released two-year follow up data comparing coronary-artery bypass grafting (CABG) with combined CABG and mitral-valve repair in patients with moderate ischemic mitral regurgitation (IMR) found no significant differences in benefit. The patients with CABG and mitral-valve repair had an early hazard of longer hospital stay post-surgery, a higher incidence of postoperative supraventricular arrhythmias and higher rate of serious neurological events than those with CABG alone. There was a three-fold higher incidence of persistent mitral regurgitation in this same group without evidence of higher mortality or adverse clinical events. The study authors conclude that physicians must weigh risks of adverse events "against the uncertain benefits" of combing mitral-valve repair during CABG.

These highly anticipated study findings, Two-Year Outcomes of Surgical Treatment of Moderate Ischemic Mitral Regurgitation, were presented today by Robert Michler, M.D. at the American College of Cardiology Scientific Session 2016 and published simultaneously in the New England Journal of Medicine by the Cardiothoracic Surgical Trials Network (CTSN).

This is the first study of its kind to provide evidence-based data on how best to treat patients needing CABG who also present with IMR. It is expected that this two-year data will impact how the medical community of physicians, surgeons and institutions will manage this patient population going forward.

"The results of this study suggest there is no significant benefit to what is often considered a routine addition to the open-heart procedure of CABG for patients with moderate IMR," said first study author Robert Michler, M.D., professor and chairman, Department of Cardiothoracic and Vascular Surgery, and the Department of Surgery at Montefiore Health System and Albert Einstein College of Medicine, and co-director of The Montefiore Einstein Center for Heart and Vascular Care. "However, after two years, we did find that the addition of mitral-valve repair provided a more durable correction of mitral regurgitation."

IMR occurs when blood backflows into the left atrium from the left ventricle of the heart due to improper closure of the MV. The condition often develops as a complication of a heart attack and subsequent enlargement of the left ventricle, the heart's main pumping chamber. Functional IMR affects 1.6 million to 2.8 million patients in the U.S. and is associated with a doubling in mortality among patients with mild or greater degrees of mitral regurgitation after a heart attack.

"The approach to managing patients with moderate ischemic MR at the time of coronary artery bypass grafting remains controversial. The results of this trial study should inform surgical decision making when caring for these complex patients," said Annetine C. Gelijns, Ph.D., the Edmond A. Guggenheim Professor of Health Policy and chair of the Department of Health Evidence and Policy at Icahn School of Medicine at Mount Sinai, and the principal investigator for the Data Coordinating Center based at Mount Sinai.

Ischemic mitral regurgitation of moderate severity develops in approximately 10 percent of patients after myocardial infarction. Mitral regurgitation is caused by the displacement of papillary muscle, leaflet tethering, reduced closing forces, and annular dilatation. Over time, the condition has an adverse effect on the rate of survival free of heart failure. Because most patients with ischemic mitral regurgitation have multivessel coronary artery disease requiring revascularization, surgeons have to consider whether to add mitral-valve repair to coronary-artery bypass grafting (CABG).

The prospective, multi-center, controlled clinical trial randomly assigned 301 patients with moderate IMR to CABG alone or CABG with MV repair. The primary endpoint was left ventricular end systolic volume (LVESVI) at one-year, assessed using a Wilcoxon rank sum test categorizing deaths as the lowest LVESVI rank.

Two-year mortality was 10 percent in CABG/MV repair patients versus 10.6 percent in CABG patients. There were no observed differences in MACCE, death, readmissions, functional status or quality-of-life at two years. Overall rates of hospital readmission and serious adverse events were similar in the two groups, but neurologic events and supraventricular arrhythmias remained more frequent in the combined-procedure group.

The CTSN DCC is based at the Icahn School of Medicine at Mount Sinai, which has eight core clinical centers in the U.S. and Canada, including Cleveland Clinic Foundation, Columbia University, Duke University, Emory University, Montefiore Einstein Heart Center, Montreal Heart Institute, University of Virginia, University of Pennsylvania and 19 Consortium sites.

This study was presented at the Featured Clinical Research Session I: Two-year Outcomes of Surgical Treatment of Moderate Ischemic Mitral Regurgitation: A Randomized Clinical Trial from The Cardiothoracic Surgical Trials Network

The Moderate Ischemic Mitral Regurgitation trial was supported by a cooperative agreement (U01 HL088942) funded by the National Heart Lung and Blood Institute, the National Institutes of Neurological Disorders and Stroke of the National Institutes of Health (NIH), Bethesda, MD, and the Canadian Institutes of Health Research.

About Montefiore Health System
Montefiore is a premier academic health system and the University Hospital for Albert Einstein College of Medicine. Combining nationally-recognized clinical excellence with a population health perspective that focuses on the comprehensive needs of the communities it serves, Montefiore delivers coordinated, compassionate, science-driven care where, when and how patients need it most. Montefiore consists of eight hospitals and an extended care facility with a total of 2,747 beds, a School of Nursing, and state-of-the-art primary and specialty care provided through a network of more than 150 locations across the region, including the largest school health program in the nation and a home health program. The Children's Hospital at Montefiore is consistently named in U.S. News' "America's Best Children's Hospitals." Montefiore's partnership with Einstein advances clinical and translational research to accelerate the pace at which new discoveries become the treatments and therapies that benefit patients. The health system derives its inspiration for excellence from its patients and community, and continues to be on the frontlines of developing innovative approaches to care. For more information please visit http://www.montefiore.org. Follow us on Twitter; like us on Facebook; view us on YouTube.

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 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 6,100 primary and specialty care physicians; 12 joint-venture ambulatory surgery centers; more than 140 ambulatory practices throughout the five boroughs of New York City, Westchester, Long Island, and Florida; and 31 affiliated community health centers. Physicians are affiliated with the renowned Icahn School of Medicine at Mount Sinai, which is ranked among the highest in the nation in National Institutes of Health funding per investigator. The Mount Sinai Hospital is ranked as one of the nation's top 10 hospitals in Geriatrics, Cardiology/Heart Surgery, and Gastroenterology, and is in the top 25 in five other specialties in the 2015-2016 "Best Hospitals" issue of U.S. News & World Report. Mount Sinai's Kravis Children's Hospital also is ranked in seven out of ten pediatric specialties by U.S. News & World Report. The New York Eye and Ear Infirmary of Mount Sinai is ranked 11th nationally for Ophthalmology, while Mount Sinai Beth Israel is ranked regionally.
For more information, visit http://www.mountsinai.org/ or find Mount Sinai on Facebook http://www.facebook.com/mountsinainyc, Twitter http://twitter.com/mountsinainyc and YouTube http://www.youtube.com/mountsinainy.