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A natural fix for heart valves

In the operating room, cardiac surgeon Joseph Woo, MD, is poised to begin a challenging operation on a man whose aorta and aortic valve have been damaged by infection.

When the valve is damaged, surgeons typically replace it, either with a mechanical valve or one taken from a pig or cow. But Woo, professor and chair of cardiothoracic surgery at Stanford, is a strong advocate for natural valve repair, or the use of a patient's own tissue to reshape and rebuild the valve to restore it to normal function.

"We’re always thinking, ‘How do you use what’s there and take advantage of it? That’s the fundamental concept to natural valve repair – to use what’s there in whatever creative manner you can to design something that works," Woo told me.

For a newly published story in Stanford Medicine magazine, I observed Woo twice in the operating room as he performed valve repairs on several patients with different conditions.

Two of these patients had damaged mitral valves, which help regulate the flow of blood from the upper left to the left lower chamber of the heart. Mitral valve repair, which originated in the 1980s, has become a more common procedure in recent years, with multiple studies showing it has many benefits over valve replacement, as patients are more likely to survive, spend less time in the hospital and suffer fewer complications, such as infection and stroke.

But aortic valve repair is newer and less commonly performed, as this valve is a "difficult nut to crack," as one noted heart surgeon told me. For one, the aortic valve has three flaps, also known as leaflets, which all have to be evenly aligned for it to open and close properly. And there's less tissue to work with in redesigning the valve, Woo says.

In the case of the patient with the heart infection, Woo opens his chest to find the aortic valve seriously impaired, with the leaflets flopping back and forth, instead of working in synchrony. He replaces the damaged aorta with a Dacron tube, then reimplants the valve back into the new vessel, using very fine sutures and tools. Most surgeons won't attempt this kind of repair, which is very challenging, but Woo knows the patient will do better if he retains his own tissues, rather than having to live with mechanical or animal parts.

After the five-hour procedure, he’s satisfied with the results. "It’s opening up nicely and closing beautifully. This patient will keep his own valve over time,” he said.

Though some conditions simply don't allow for repair, Woo takes an "all-repair" approach, trying to consider each patient a possible candidate. He often gives talks to cardiologists and heart surgeons throughout the world, promoting this idea and repair techniques.

“We believe, in our hands, we can try to approach everyone as potentially reparable,” he told me. “No one should be automatically viewed as not being a repair candidate. Everyone should have an opportunity.”

Previously: Stanford Medicine magazine puts spotlight on pediatric care and Stanford study helps surgery patients make difficult heart valve choice
Photo by Leslie Williamson

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