'Closed-heart surgery' may offer new alternative
"Dr. Samuel Lichtenstein cut a two-inch hole between an elderly man's ribs. Peering inside, he poked a pencil-sized wire up into the chest, piercing the bottom of the man's heart.
Within minutes, Bud Boyer would have a new heart valve — without having his chest cracked open. Call it closed-heart surgery."
" 'I consider it some kind of magic,' said Boyer, who left the Vancouver, British Columbia, hospital a day later and was almost fully recovered in just two weeks.
In Michigan, Dr. William O'Neill slipped an artificial valve through an even tinier opening — pushing it up a patient's leg artery until it lodged in just the right spot in the still-beating heart.
The dramatic experiments, in a handful of hospitals in the U.S., Canada and Europe, are hunting easier ways to replace diseased heart valves that threaten the lives of tens of thousands of people every year — starting with the aortic valve that is the heart's key doorway to the body.
The need for a less invasive alternative is huge, and growing. Already, about 50,000 Americans undergo open-heart surgery every year to replace the aortic valve: Surgeons saw the breastbone in half, stop the heart, cut out the old valve and sew in a new one. Even the best patients spend a week in the hospital and require two or three months to recuperate.
Thousands more are turned away, deemed too ill to survive that operation and out of options. Demand is poised to skyrocket as the baby boomers gray, because the aortic valve is particularly vulnerable to rusting shut with age.
A radical new alternative?
The new experiments are a radical departure from that proven, if arduous, surgery.
The artificial valves don't even look like valves, squished inside metal cages until they're wedged into place. With barely 150 of any type implanted worldwide, most in the last year, no one knows if they'll work as well as traditional valve replacements, which last decades.
So for now, the only patients who qualify are too sick to be good candidates for regular valve replacement.
Some deaths during the earliest attempts at implanting the devices forced doctors to come up with safer techniques. Clinical trials apparently are back on track, and even the most skeptical cardiologists and heart surgeons are closely watching how these pioneers fare.
The hope is that one day, replacing a heart valve could become almost an overnight procedure.
'There's lots of technical challenges that need to be overcome,' cautioned Dr. Robert Bonow, a valve specialist at Northwestern University, who is monitoring the research for the American Heart Association. But, 'most of us do think this is the future,' he said.
O'Neill's first successful patient in March celebrated the one-year anniversary of his through-the-leg implant.
'I call it a new birthday,' chuckled Fred Grande, 78, a Richmond, Mich., car collector who took one of his beloved models for a fast spin less than a week after the procedure.
'That's the home run we want to hit with all the patients,' said O'Neill, cardiology chief at William Beaumont Hospital in Royal Oak, Mich.
'It's gratifying' to watch people once deemed beyond help bounce back, added Dr. Jeffrey Moses of New York-Presbyterian Hospital/Columbia University, who with O'Neill is leading the U.S. study. One of Moses' first patients is playing golf at age 92.
225,000 valves replaced each year
The heart has four valves, one-way swinging doors that open and close with each heartbeat to ensure blood flows in the right direction. More than 5 million Americans have moderate to severe valve disease, where at least one valve doesn't work properly, usually the aortic or mitral valves. Worldwide, roughly 225,000 valves are surgically replaced every year.
Topping that list is the aortic valve, which can become so narrowed and stiff that patients' hearts wear out trying harder and harder to push oxygen-rich blood out to the rest of the body.
Calcium deposits accumulate on its tender leaflets. Touch one chipped out of a patient, and it feels almost like a rock.
With minimally invasive valve replacement, doctors don't remove that diseased valve. Instead, they prop it open and wedge an artificial one into that rigid doorway.
'It's ironic: You use the disease process to actually help hold your valve in place,' explained Lichtenstein, of St. Paul's Hospital in Vancouver, who helped create the between-the-ribs method.
Different approaches tested
Two manufacturers — Irvine, Calif.-based Edwards LifeSciences, the biggest maker of artificial heart valves, and Paris-based CoreValve — are testing versions of a collapsible valve made of animal tissue that is folded inside a stent, a mesh-like scaffolding similar to those used to help unclog heart arteries.
The difference is how doctors get the new valve to the right spot, pop open its metal casing and make it stick:
The U.S. studies thread the Edwards valve through a leg artery up to the heart, so-called 'percutaneous valve replacement.' Unlike with open-heart surgery, doctors don't stop the patient's heart. So the trickiest part is keeping regular blood flow from washing away the new valve before it's implanted. Once the device is almost in place, doctors speed the heartbeat until normal pumping pauses for mere seconds — and quickly push the new valve inside the old one. Inflating a balloon widens the metal stent to the size of a quarter, lodging it into place and unfolding the new valve inside, which immediately funnels the resuming blood flow.
So far, 19 Americans have been implanted this way, plus more than 80 other people worldwide, most of them in France by the procedure's inventor, Dr. Alain Cribier, and in Vancouver by Lichtenstein's colleague, Dr. John Webb.
Fourteen people in Canada, Germany and Austria have received the Edwards valve through the ribs, a more direct route to the heart for patients whose leg arteries are too clogged to try the other experiment. Doctors make a tiny hole in the bottom of the heart muscle so the new valve can enter, and then use the same balloon technique to wedge it inside the old valve. Talks have begun with the Food and Drug Administration about opening a similar U.S. study later this year.
CoreValve's slightly different valve is being tested in Europe and Canada. It, too, is threaded up the leg artery. But it's made of pig tissue instead of horse tissue and, the key difference, has a self-expanding stent that requires no balloon. Doctors remove a sheath covering it and the stent's metal alloy, warmed by the body, widens until it lodges tight against the old, rocky valve. More than 45 have been implanted, and CoreValve hopes to begin a U.S. study next year. Meanwhile, lead researcher Dr. Eberhard Grube of The Heart Center in Siegburg, Germany, expects within months to begin testing a newer version small enough to thread through an artery at the collarbone, another more direct route to the heart.
Experiments pose major risks
The experiments come with some significant risks. Indeed, Edwards temporarily halted the U.S. study last year after four of the first seven U.S. patients died. Initially, doctors threaded the valve up a leg vein, not an artery, a route that required tortuous turns inside the heart that sometimes damaged a second valve, explained O'Neill.
Twelve people have been implanted since the study re-started in December using the artery route considered easier and safer; all but one have survived and are faring well, researchers say.
O'Neill and Moses — plus doctors at a third hospital, the Cleveland Clinic — have government permission to implant eight additional patients in the U.S. pilot study, which will be expanded if it goes well.
CoreValve's first four patients also died as doctors struggled to develop and learn the through-the-artery technique, Grube said.
For doctors, pushing the large valve through tiny, twisting arteries — against regular blood flow and guided by X-rays — is laborious. Occasionally, they aren't able to wedge it into position.
And because they're squeezing a round valve into an irregular-shaped opening, there's a risk that the new valve will leak blood backwards into the heart, also problematic.
Do benefits outweigh dangers?
But once researchers master how to get the valve into place safely, the question becomes how much recipients benefit: do these very ill patients live longer than expected? If not, does quality of life improve enough to warrant the procedure anyway?
It's too soon to know.
But three of French inventor Cribier's original patients have lived 2 1/2 years so far, with a 'return to normal life and no sign of heart failure,' he said. Eleven others have lived a year and counting.
CoreValve reports five patients faring well a year later.
Aside from those who didn't survive the implantation, others have died from their advanced illnesses even though their new valve was working.
It is the handful of astounding successes — people like Grande and Boyer — that have other heart specialists taking note, said Northwestern's Bonow.
'Patients have to know what they're getting into,' he stressed. Many of the seriously ill are willing to chance the experimental procedure because 'they're so debilitated and ... there have been some good examples of patients who have gotten better.'
The bigger challenge, Bonow added, is whether to expand the studies to include less sick patients who could survive open-heart valve replacement but want to avoid its rigors. Already, there are such patients clamoring to be included.
'There is a trade-off'
That's a difficult decision, because even 80- and 90-year-olds can undergo regular valve replacement successfully. When performed by the most skilled surgeons, risk of death from the operation is about 2 percent — but in less experienced hands, it can reach 15 percent, Bonow said.
Just as using a balloon to unclog heart arteries is sometimes done on patients who'd fare better with bypass surgery, eventually researchers will have to ask if patients would accept a less-than-perfect aortic valve if they got to skip surgery's pain and risks, said Dr. Michael Mack of Medical City Hospital in Dallas.
'There is a trade-off, and how you make that trade-off is a totally gray area,' he said.
But Vancouver's Boyer — who underwent two previous open-heart surgeries for clogged arteries — said avoiding that kind of pain isn't a trivial issue for patients.
'They're doing something to the field of medicine that's going to make life a hell of a lot easier to people who've got that problem,' said a grateful Boyer, describing how he could finally breathe easy after the through-the-ribs valve implant. 'I think I'll have a bunch of other parts go bad before I have a problem with this'."
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Copyright 2006 The Associated Press
© 2006 MSNBC.com
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