2013, November 18, 2013
A key North American study published today in The New England Journal of Medicine
Montréal, November 18, 2013 – A study published today in The New England Journal of Medicine and presented at the American Heart Association's Scientific Sessions 2013 marks a decisive step in the practice of heart surgery. A group of North American researchers compared two types of heart surgery to treat mitral valve failure, a very common heart defect that is estimated to affect approximately one out of five people over the age of 55. The study results seem to indicate that mitral valve replacement provides longer lasting protection than mitral valve repair.
The Severe MR study - Evaluation of Outcomes Following Mitral Valve Repair/Replacement in Severe Chronic Ischemic Mitral Regurgitation, was directed by the Cardiothoracic Surgical Trials Network that includes the National Institutes of Health (NIH); the National Heart, Lung, and Blood Institute (NHLBI); and the Canadian Institutes of Health Research (CIHR). The group of researchers from Université de Montréal were part of the 10 main investigational sites. The Canadian sites recruited nearly 20% of all participants for this study.
“Current practice tends to focus on valve repair (annuloplasty) instead of replacement. However, our study did not show that repair is the most effective treatment. Our findings therefore have major clinical repercussions in the field of heart surgery,” explained Dr. Louis Perrault, lead investigator for the Canadian arm of the study, Chief of Service of the Department of Cardiac Surgery at the Montreal Heart Institute and Professor in the Faculty of Medicine at Université de Montréal.
Overall, 251 patients with severe mitral valve failure participated in this study. They were randomly assigned to one of two groups that were treated either with a mitral valve replacement or with annuloplasty.
Follow-up was during 24 months after the surgery. The success of the procedure was assessed by measuring the size of the left ventricle, which enlarges when the heart valve chronically leaks. They also measured patient health based on the number of deaths, severe heart problems, stroke and hospital readmissions as well as an assessment of quality of life. After one year, there was almost no clinical difference between the two groups.
The only significant gap was a higher rate of recurrent regurgitation in the group that had undergone annuloplasty (32.6% compared to 2.3% in patients who had a mitral valve replacement). This is in line with valve replacement, which offers longer-term protection. It should be noted that regurgitation did not lead to any increase in health problems for patients in the mitral valve repair group.
About mitral valve failure
Mitral valve failure (or mitral valve regurgitation) is the most common type of heart valve disease. This condition occurs when the anterior and posterior flaps of the valve do not close completely, which causes abnormal blood backflow from the left ventricle to the left atrium. Its more severe form can lead to heart failure and death. Open-heart surgery is the current treatment standard for this condition.
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