An international study of more than 400 adults concludes that people who undergo mitral valve surgery (between the left atrium and the left ventricle of the heart) and also have less than severe leakage of the tricuspid valve (a section of the heart that directs blood from the right atrium to the ventricle) may benefit from having both valves repaired at the same time. The study found that simultaneous repair decreased the risk of future severe leakage of the tricuspid valve.

The results of the clinical trial were presented Nov. 13 at the American Heart Association’s annual Scientific Sessions meeting. The full study was published simultaneously in the New England Journal of Medicine.

Heart valves are responsible for regulating blood flow to and from the four chambers of the heart. The valves have leaflets, thin but strong flaps of tissue that work to keep blood from leaking back into the heart. When a valve leaks, it is known as regurgitation. Symptoms of such leaks include shortness of breath, fatigue and dizziness.

Leaky mitral valves are the most common type of heart valve abnormality, and are most often repaired or replaced by surgery. In the U.S., more than 50,000 operations are performed to fix mitral valve regurgitation annually.

To repair the tricuspid valve, a ring is implanted around the valve to treat and prevent progression of leaks and the fluid accumulation in the heart that is an independent risk factor for increased risk of death in the long term.

 “There’s a general agreement among surgeons that if there is severe leakage of the tricuspid valve, then we should fix it,” said lead investigator James Gammie, M.D., surgical leader and co-director of the Heart and Vascular Institute at the Johns Hopkins University School of Medicine. “However, there has been considerable uncertainty as to whether the tricuspid valve needs repair at the time of mitral valve surgery when the leakage is only moderate or less.”

To study the potential effectiveness and safety of less than moderate tricuspid valve repair during mitral valve surgery, researchers conducted an international, multicenter, randomized controlled trial at 39 locations across the U.S., Canada and Germany between 2016 and 2018. A total of 401 adults were included in the study; 203 had only the mitral valve operation, while 198 had mitral valve surgery plus tricuspid valve repair. The participants were primarily white men (91% white; 75% male) and on average were 67 years old. Researchers assessed the rate of death, repeat operation for tricuspid regurgitation and progression of tricuspid valve leakage.

After a two-year follow-up of participants, the researchers found that overall, those who had both their mitral valve and their tricuspid valve problem repaired at the same time experienced better outcomes, such as less progression to moderate or severe leakage and improved treatment success than those who had only their mitral valve repaired.

The study’s key findings:

• Only 3.4% of people who had both valves repaired progressed to moderate or severe tricuspid regurgitation after two years, compared with 25% of those who had the mitral valve surgery alone.
• Less than 1% (0.6%) of patients who had both valves fixed progressed to severe tricuspid regurgitation after two years, compared with 5.6% of those in the mitral valve-only surgery group.
• The treatment failure rate, defined as death and/or reoperation for tricuspid valve surgery, was higher (10.2%) among the group that did not have their tricuspid valve fixed at the same time as mitral valve surgery, compared with those who did (3.9%).

The death rate for participants undergoing modern mitral valve surgery was less than 1%, and two years later the survival was over 96%. While repairing the tricuspid valve during mitral valve surgery limited leakage and potential damage to the heart, researchers also found disadvantages:

• The addition of tricuspid valve repair prolonged the length of surgery time and time spent on a heart-lung machine by 34 minutes.
• Permanent pacemakers were needed in 14% of patients in the tricuspid valve repair group compared with 2.5% of patients who had the mitral-only surgery. Researchers note this did not appear to have a negative impact on patients.
• Patients had a longer median hospital stay by two days.

 “We clearly need to better understand the risk factors for needing a permanent pacemaker implanted after tricuspid valve repair and how to best mitigate the risk with technique modifications or different postoperative management strategies,” says Gammie. “But for the first time, we have high-level evidence to help us understand what to do in the operating room when it comes to tricuspid valve repair in those with less than severe regurgitation.”

Gammie says the trial is designed to continue to follow patients up to five years after surgery to see if there is further progression of tricuspid valve leakage.

Other researchers involved in this study include Michael Chu of Western University, London Health Sciences Centre; Vokmar Falk of Charité Universitätsmedizin Berlin; Jessica Overbey, Alan Moskowitz, Eric Rose, Samantha Raymond, Ellen Moquete, Karen O’Sullivan, Mary Marks, Emilia Bagiella and Annetine Gelijns of Icahn School of Medicine at Mount Sinai; Marc Gillinov of The Cleveland Clinic; Michael Mack of Baylor Scott & White Health; Pierre Voisine of Institut Universitaire de Cardiologie et de Pneumologie de Québec; Markus Krane of Yale School of Medicine; Babatunde Yerokun of Duke University; Michael Bowdish of Keck School of Medicine of USC; Lenard Conradi of University Heart Center Hamburg; Steven Bolling and Goray Ailawadi of University of Michigan Health System; Marissa Miller, Wendy Taddei-Peters and Neal Jeffries of the National Heart, Lung, and Blood Institute; Michael Parides of Albert Einstein College of Medicine; Richard Weisel of Toronto General Hospital and University of Toronto; Mariell Jessup of the American Heart Association; John Mullen of University of Alberta, Edmonton, AB; Alexander Iribarne of Dartmouth-Hitchcock Medical Center; Friedhelm Beyersdorf of University Heart Center Freiburg; Michael Borger of University of Leipzig; Arnar Geirsson of Yale School of Medicine; Judy Hung of Massachusetts General Hospital; and Patrick O’Gara of Brigham and Women’s Hospital.

Funding for this trial was supported by a cooperative agreement (U01 HL088942) funded by the National Heart, Lung, and Blood Institute and a grant from the German Centre for Cardiovascular Research.

Authors have no conflicts of interest to report.