Until now, replacing a malfunctioning aortic valve required open-heart surgery, which involves cutting through the breastbone to provide access to the heart. Although the surgery, done more than 500,000 times a year in the United States, is remarkably safe, it may be too demanding for the elderly — precisely the people most likely to need an aortic valve replacement. • Now, however, two new procedures allow aortic valve replacement without open-heart surgery. One procedure doesn't even involve surgery.
Each time the heart beats, blood surges through the aortic valve and begins its trip through the body. The valve, which resembles a Mercedes-Benz logo, consists of three leaflets, or flaps, that close tightly between heartbeats to prevent blood from flowing backward into the heart, but open widely when the heart contracts to let blood out. At least that's what happens when the valve is healthy.
With age, the leaflets in the aortic valve of some people become thick and stiff, barely opening wide enough to let blood out. As a result, the muscular wall of the left ventricle below the valve thickens to overcome this resistance, and that produces another problem. A thick heart wall can disrupt the electrical cascade that produces each heartbeat, which can result in sudden cardiac death unless defibrillator paddles are used.
The replacement valve
The only effective treatment for the narrowing of the valve, called aortic stenosis, involves replacing the stiffened valve with an artificial valve. Among the options is a durable mechanical valve, a tissue valve made from the aortic valve of a cow or a pig, or a transplanted valve from a donated human heart.
Each has drawbacks. The mechanical valve causes blood clots, which require lifelong treatment with blood thinners that increase the risk of brain bleeds. The tissue valves wear out, usually in 10 to 15 years. Availability of homografts is also an issue.
Despite these limitations, an artificial valve restores blood flow out of the heart and into the aorta, which usually reduces or eliminates symptoms. People with aortic stenosis who could not even climb a flight of stairs may find themselves free of chest pain, shortness of breath and other symptoms after they receive a new valve.
But open-heart surgery may not be an option for those elderly patients deemed too frail or sick.
An alternative approach
Some surgeons have developed minimally invasive techniques without the trauma of open-heart surgery.
Dr. Joseph Lamelas, for example, chief of cardiac surgery at Mount Sinai Medical Center in Miami, has developed a technique that involves making a 3-inch incision in the chest between two ribs to gain access to the aorta without damaging the sternum or any other bones. Recovery tends to take days instead of weeks, with much less pain, as I can attest, having had the surgery. The technique achieves superior results, according to data he has published in the January and February issues of the Annals of Thoracic Surgery. People who undergo the minimally invasive technique, for example, average seven days in the hospital instead of 12 days, according to Lamelas and his co-authors. They also have half as many complications and experience dramatically lower rates of infection and kidney failure.
Lamelas has been teaching the technique to surgeons around the world, but minimally invasive aortic valve replacement is relatively rare.
"Many patients don't know about it," Lamelas said, "and this procedure is definitely more challenging technically. No doubt, there is a learning curve, but there is a learning curve with everything."
Yet another option
Another technique, currently experimental and limited to elderly patients too frail to endure open-heart surgery, is known as transcatheter aortic valve implantation (TAVI). The procedure involves making a tiny incision near the groin to gain access to a blood vessel that provides a highway to the heart. A catheter that contains a new valve compressed inside is inserted into the femoral artery and threaded to the center of the aortic valve. When the new valve is released and inflated, it crushes the old valve and takes its place, getting right to work. Even elderly patients often go home the next day.
The only problem is that this experimental technique is limited to elderly patients with severe aortic stenosis. However, the results so far have been very encouraging, and will be available soon at 40 sites across the country, including Mount Sinai.
"We are one of the 40 sites that have been accepted for the trial," Lamelas said. "TAVI will have its role in a certain subset of patients, initially the high-risk or inoperable patients, but it will complement, not replace, surgical approaches."
A caveat: As you consult with your cardiologist about less-invasive options, carefully consider the doctor's reports and recommendations intended for you. No two patients are alike.
Tom Valeo writes frequently about health matters. He can be reached at firstname.lastname@example.org.
Aortic valve images provided courtesy of Healthwise Inc.