Conference Coverage

Age, anticoagulation prime issues in choice of mechanical valves


 

EXPERT ANALYSIS FROM THE 2017 MITRAL VALVE CONCLAVE

– While bioprosthetic valves have become the predominant choice for cardiothoracic surgeons performing heart valve replacement, situations exist in which a mechanical valve may be a better choice. Young and middle-aged adults are the ideal candidates for mechanical valves, but achieving long-term success with mechanical valves also depends on a patient’s circumstances, according to an expert panel at the American Association for Thoracic Surgery Mitral Conclave 2017 here.

“I think we should put in more mechanical valves,” said panel chair Thoralf M. Sundt III, MD, of Massachusetts General Hospital, Boston and former AATS president. “I think mechanical valves have gotten a bad rap. If patients have a supportive, stable social structure and they can manage their anticoagulation, I don’t think there’s anything wrong with a mechanical valve. I think the pendulum has swung too far.”

Dr. Thoralf Sundt III
Dr. Thoralf Sundt III
Socioeconomic factors can play a role too, Dr. Sundt said. “It depends a lot on what the risk and practicality of a reoperation are like,” he said. “There are environments where a reoperation just isn’t an economic possibility. If you’re in a country where a family has to sell the farm in order to get the first operation, there’s not going to be a second operation.”

Anelechi C. Anyanwu, MD, of Mount Sinai Health System, New York, acknowledged another patient factor that would enter his calculus for recommending a mechanical mitral valve. “We would consider a mechanical valve in the patient who is compliant [and] well informed and understands well the requirements and implications of long-term anticoagulation,” he said. In another scenario – “the patient who’s had multiple reoperations – we may consider a mechanical valve.” Particularly, the patient who has had a reoperation for a bioprosthetic valve resulting from early degeneration will merit consideration of a mechanical prosthesis, Dr. Anyanwu said.

Michael A. Borger, MD, of Columbia University Medical Center, New York, agreed that the younger patient who has had a series of operations is a good candidate for a mechanical mitral valve. “In addition, the mechanical valve does have some hemodynamic advantages over bioprosthetic valves,” Dr. Borger said. “If a surgeon implants a 25-mm tissue valve with a plan for the patient to undergo a series of valve-in-valve operations in the future, mitral stenosis will definitely become a factor at some point.”

Dr. Anelechi Anyanwu
Dr. Anelechi Anyanwu
Small children are another population in which mechanical valves may be considered, but the long-term success rate has been discouraging, said Rudiger Lange, MD, of the German Heart Center, Munich.

Pedro J. del Nido, MD, a pediatric cardiac surgeon at Children’s Hospital, Boston, expanded on that point. “We very, very rarely use mechanical valves in young patients,” Dr. del Nido said. “In very young patients, the reoperation rates for mechanical or biological valves are not much different. We still have to reoperate on both sets of patients. But, the reoperation itself for a mechanical valve is more difficult, and there is the need for full anticoagulation.”

Instead, Dr. del Nido has used the bovine Melody valve (Medtronic) in the mitral position for these patients because it accommodates some growth. Typically, the only time Dr. del Nido considers a mechanical valve in these young patients is for an aortic valve replacement.

Another younger patient that may be a good candidate for a mechanical valve is the 25-year-old male with rheumatic mitral stenosis. “I would err on the side of the mechanical valve in this patient if I were to make a choice, but I would present the patient with informed data on the outcomes of both mechanical valve and bioprosthesis,” according to Dr. Anyanwu

Dr. Pedro del Nido
Dr. Pedro del Nido
However, Dr. Lange would still opt for a biological valve in that 25-year-old. “The patient’s preference is important,” he said. “I would rather put in a biological valve in this patient – maybe put two more transcatheter valves transeptally in the future and do one reoperation.”

For even younger patients, Dr. del Nido bases his valve choice on their activity level. “I have a lot of young teenagers, and my decision is entirely based on what their background is like – what their regular life is like,” he said. “If they have a support structure than can help them manage anticoagulation, absolutely the mechanical valve is probably the best thing.”

However, there are exceptions because the couching of the device can change over time. “Eventually that 12-year-old [or] that 15-year-old is going to decide he can still snowboard or ride a motorcycle, and that’s when he’s going to get into trouble,” Dr. del Nido said. “If a reoperation is not problematic, I would still say it’s a tossup between the mechanical and biological valve. I would still offer the possibility of a bioprosthesis knowing that they’ll be back in 6, 8, or 10 years.”

Bleeding risk is another factor that can influence valve choice, as mechanical valve recipients must stay on anticoagulation. “The bleeding complication rates are very low when patients are younger, in their 40s or 50s, but the bleeding rates increase exponentially with warfarin for patients in their 80s and 90s,” Dr. Borger said. “The older you are, the more difficult it is to manage anticoagulation. In addition, the ability to stop anticoagulants because of bleeding is different for the two types of prostheses. If a patient develops bleeding during anticoagulation for leaflet immobility after a tissue valve-in-valve procedure, the physician can simply stop the warfarin. But, if you have a mechanical mitral valve in place that’s not an option.”

That’s not necessarily a bad problem to have, Dr. Sundt said, quoting Steven Bolling, MD, of the University of Michigan. “If you’re 25 and you’ve had your valve replaced and you’re worried about bleeding at the age of 80, I call that a success.”

Dr. Borger disclosed he is a speaker for and consultant to Edwards Lifesciences, Medtronic, and CryoLife; a speaker for St. Jude; and a recipient of research support from NeoChord. Dr. Lange disclosed he is a consultant and speaker for Medtronic, St. Jude/Abbott, LivaNova and NeoChord and cofounder of HighLife. Dr. Anyanwu, Dr. del Nido, and Dr. Sundt reported no relevant financial relationships.