Latest Heart Valve Treatment Allows Patients To Avoid An Open-Heart Surgery
Currently used for patients for whom an open-heart surgery can be fatal, doctors are trying make transcatheter aortic valve replacement a treatment for all patients with an aortic valve disease.
Use of transcatheter for an aortic valve replacement is a more viable option
- About 8 million americans suffer from heart valve disease at a given time
- Surgeons wish to use a transcatheter for mitral and pulmonary valve too
- An open-heart surgery is still much more safe in a long run
"I was pretty sore, but the pain went away over time, and by the first week of January I was back on the treadmill," he says.
Within the next few years, based on the results of a study now underway, people like my brother might be able to choose a less-invasive option that would get them home within three days and take half the recovery time, although, as with most procedures, there are risks.
Transcatheter aortic valve replacement, or TAVR (also called TAVI, for transcatheter aortic valve implantation), currently is approved only for patients who cannot have open-heart surgery or for whom it would be risky. These include the elderly and frail, and people with complications such as kidney disease and coronary obstructive pulmonary disease.
For many of them, TAVR has been lifesaving. "We're very thankful to have this technology," says Paul Stelzer, a cardiac surgeon at Mount Sinai Hospital in New York, who operated on my brother. "Now we can do something for octogenarians and 90-year-olds we couldn't help before."
Many experts believe that TAVR will become the first-line valve replacement treatment for almost everyone with aortic valve disease.
"I think transcatheter valve technology is going to rule," says Joseph E. Bavaria, co-director of the transcatheter valve program at the University of Pennsylvania. "It's a great technology, a radical, revolutionary technology. You don't have to open up the chest and put somebody on a heart-lung machine. In the future - I can't tell you when, but at some time - most aortic valve procedures will be done through a transcatheter approach."
TAVR involves threading a catheter tipped with a replacement valve through a blood vessel to the heart, where the surgeon pushes the old valve open, places the new one inside, and expands it to fit. The old valve remains, but the new one takes over its work. Surgeons now use TAVR only for aortic valves, but experts hope there will be a role for it in replacing other valves.
About 8 million Americans suffer from heart-valve diseases at any given time, with nearly 6 million diagnosed annually, according to the American Heart Association. Not everyone ends up having replacement surgery: Treatment depends on disease severity and whether it is worsening. Also, many valves can be repaired rather than replaced. Almost 83,000 valve replacements were performed in the United States during most of 2017, according to the Society of Thoracic Surgeons, and more than half of them were TAVR procedures.
In addition to the aortic valve, there are three others: the mitral, the tricuspid and the pulmonary. All have tissue flaps that open and close with each heartbeat, ensuring that blood flows in the right direction through the heart's four chambers.
When valve problems occur, they usually involve regurgitation or backflow when a valve doesn't close tightly, often a cause of mitral valve prolapse, in which blood leaks back into the chambers; stenosis, which is when a valve becomes thick or stiff, or fuses together, and can't fully open; and atresia, when the valve lacks an opening.
Heart-valve disease can afflict one valve or several in combination, but the aortic and mitral valves are the ones most frequently affected.
No one knows why the aortic valve is prone to narrowing, "but it seems to be associated with aging," says A. Marc Gillinov, chairman of the Department of Thoracic and Cardiovascular Surgery at Cleveland Clinic, which performs more heart-valve surgery than any other facility in North America. He predicts: "The longer we live, the more we will see."
The heart association estimates that about 25,000 people die annually from underrecognized valve disease, especially from aortic stenosis. It includes such symptoms as shortness of breath, lightheadedness or fainting, and chest pain. But sometimes there are no warning signs. My brother was asymptomatic until the day he nearly fainted during a treadmill workout and a stress test revealed that his blood pressure was dangerously low.
"The doctor gave me Dr. Stelzer's number and told me to call him right away and say it was urgent," he recalls.
TAVR evolved from the frustration of cardiac surgeons over their inability to treat valve disease patients who were too old, too frail or too sick for open-heart surgery. A French surgeon, Alain Cribier, performed the world's first transcatheter aortic valve replacement in 2002.
Since then, studies have shown TAVR's efficacy in two groups of patients with health problems. These include high-risk patients, whose age and health issues make them ineligible for open heart surgery, and a second group with less severe health problems for whom open heart surgery would be risky, but not impossible.
The initial study among high-risk patients compared TAVR to standard therapy - but not open-heart surgery - such as balloon valvuloplasty. This procedure threads a catheter with a balloon at its tip through a blood vessel to the faulty valve, where the balloon inflates to widen the defective valve. The study found that patients getting TAVR died far less frequently than those receiving the standard treatment.
Another study compared TAVR to open-heart surgery among those at intermediate risk and found no significant difference between the two, making TAVR a viable option and "a big win for transcatheter valve technology," Bavaria says.
A current study compares TAVR with open-heart surgery in low-risk patients like my brother. "Right now, the choices are to have normal surgery or participate in a clinical trial," Stelzer says, although he thinks the Food and Drug Administration probably will approve it for this group. "Patients want it. They prefer having a less-invasive procedure over having their chest cracked," he says.
Still, "I prefer doing open-heart on my low-risk patients," Stelzer adds. "It takes a couple of months to get over, but I think they're better off in the long run."
Studies also are looking at using a transcatheter approach for mitral valves, although, unlike aortic valves, mitral valves often can be repaired. "You are better off with a good repair of your own valve," Gillinov says. "Also, if you are going to try to replace a mitral valve with a catheter valve, you don't have as favorable a 'landing zone.' The calcium of the aortic valve gives you an anchoring substance, while the mitral valve usually isn't calcified."
TAVR valves can be expensive, which usually means insurance probably won't cover them for unapproved patients. A TAVR valve - just the device itself - costs about $30,000 compared with about $5,000 for a valve used in open-heart surgery.
And TAVR is not risk-free.
The earliest TAVR devices - since modified - were stiff and bulky. When surgeons pushed them into place, they sometimes dislodged pieces of calcium from the old valve, sending them to the brain, causing stroke. The latest valves are smaller and more flexible, and the risk of stroke has decreased dramatically.
But problems remain. TAVR sometimes disrupts the heart's conduction system, increasing the need for a pacemaker. A recent study found that this complication lengthens hospital stays and may worsen survival. Also, TAVR valves leak. "About 40 percent of patients have a leak," Bavaria says. "But they are usually trivial or mild."
Bavaria, who also chairs the Society of Thoracic Surgeons' transcatheter valve therapy steering committee, says he believes these problems are not permanent. "It will take some time, but I believe the problems will be fixed," he says.
There is another side effect to TAVR, which is rare but potentially deadly. In about 1 percent of patients - those whose hearts have uncommon structures, such as unusually large valve leaflets (leaflets are flaps that ensure one-way blood flow) or small aortic roots - the large leaflets can block the flow of blood to the coronary arteries as the new valve's scaffolding opens. This can cause a fatal obstruction.
Since the old valve remains, "surgeons squash it aside, which is fine, most of the time," says Jaffar Khan, a cardiologist and staff clinician at the National Heart, Lung, and Blood Institute. But in rare cases, "these leaflets act like a trap door that shuts the coronary arteries. The TAVR valve pins the old valve up against the entry of the coronary artery, with no way for the blood to flow," he says. "Essentially, you've created a massive heart attack."
Khan and his NHLBI colleague Robert Lederman recently developed a method to prevent this. In this approach, the surgeon weaves an electrified wire the size of a sewing thread through a catheter and uses it to split the original leaflet in two so it cannot block the coronary artery. Potential TAVR patients are screened in advance to identify those at risk and sent to a specialized center where surgeons are trained in the new procedure.
Meanwhile, the study in low-risk patients is expected to wrap up by next spring, and most experts believe it will show the same safety profile as open-heart surgery, paving the way for wider use of TAVR. "I think the (patient groups) will continue to expand," Gillinov says. "It has become very safe."
My brother, now 81, says his new valve - which should last another decade - apparently is working fine. Still, he complains, albeit good-naturedly. "I can't do all the things I used to do, like hills," he says of his walking regimen. "But I think that probably has more to do with my age than my heart."
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
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