The fact that surgeons have cut out the hearts of five terminally ill men and put in artificial ones is amazing enough all by itself. But what absolutely stuns the people who build and install the hearts is what has happened since.
Everything works. There has hardly been a glitch worth mentioning. In the four months since the first operation, the mechanical hearts have never missed a beat. And they clearly are saving the patients' lives.
A 100 percent success rate? With a brand-new, last-ditch treatment tested for the first time on the terminally ill? Doctors say that is just about unheard of in medicine.
"The most surprising thing of all to me is there have been no surprises so far," says David Lederman, president of Abiomed, the suburban Boston company that made the heart.
Doctors caution that bad things can still happen. In fact, they probably will. But for now, against incredible odds, all of the patients are getting better or at least holding their own.
When this started, they were literally at death's door with congestive heart failure. None was thought to have more than a 10 percent chance of surviving another month. Their hearts could not pump powerfully enough to keep their bodies working. As a result, all had damaged organs _ bad lungs, livers, kidneys and more.
They were so sick that Dr. Robert Dowling said he would have felt lucky if one or two had hung on for a couple of months with the mechanical hearts. He implanted the first two at Louisville's Jewish Hospital. The fifth was implanted just last week.
Recovery is slow. But in general, doctors say that step by step the men are overcoming the injury caused by their former weak hearts and returning to health. Now, Dowling is talking about sending his first patient home to Franklin, Ky., maybe by Christmas, with a plastic and titanium pump beating 200,000 times a day inside his chest.
Dr. O.H. Frazier, transplant chief at the Texas Heart Institute in Houston, calls the five men's survival "unprecedented in this field." He did the first implant of this artificial heart in a calf in 1989 and knows how badly things can turn out in the early going. Years earlier, he was among the first to test the HeartMate, a device that gives the damaged heart a boost without replacing it.
"The first four patients that I implanted that in all died," he says. "That's been the experience with most technology. The early patients don't make it."
The five latest patients made it because of the AbioCor, which is the first of its kind _ a self-contained, no-wires-attached, fully implantable replacement for the human heart. If the doctors who have tested it are right, it is also likely to be the first truly practical artificial heart, an off-the-shelf item that could save the lives of tens of thousands of Americans who die each year with irreparably weakened or damaged hearts.
The AbioCor is the first artificial heart to reach this stage of testing since the introduction of the Jarvik-7 in 1982. The first patient, Barney Clark, lived 112 days. Another, William Schroeder, survived for 620. But they were tethered to a noisy 300-pound console and were beset with complications, such as infections and strokes.
Two decades of miniaturization and other improvements have led to the grapefruit-size AbioCor. It hums quietly and, most important, is fully enclosed in the chest. Its internal battery is recharged across the skin, so no wires stick out.
"Until this device, there always was some sort of tube coming out through the skin to connect to batteries," says Dr. Fred Grover of the University of Colorado. "No matter how clever you are, you always have the risk of infection."
Other complications doctors worry about are strokes, serious bleeding and mechanical breakdown. None of those things has happened.
Abiomed officials try not to seem overconfident, but at the same time they talk about their timetable for bringing the artificial heart to market.
"It's still too early to claim clinical success," says Lederman. "We still have a lot to learn. But so far we are encouraged and amazed at how well the device is working and how patients who are facing imminent death can be rehabilitated."
Next year, the company plans to do 10 more in the United States, start testing in Europe and, if all goes well, formally ask the Food and Drug Administration for permission to sell the device. It could be on the market in mid to late 2003.
Dowling and Dr. Laman Gray Jr. implanted the first AbioCor on July 2 in Robert Tools, a 59-year-old diabetic with a long history of heart trouble. In mid September, he ventured out of the hospital for the first time, taking a van ride to a park with a side trip to a White Castle for a cheeseburger.
Tools' major health problem now is poor appetite _ a common issue with heart failure patients _ but Dowling says if he puts on 10 or 20 pounds, he can go home for good.
The same Louisville team performed the second operation Sept. 13 on Tom Christerson, 70. Frazier did the third on Sept. 26 at Houston's St. Luke's Episcopal Hospital. The fourth was Oct. 17 at UCLA Medical Center. The fifth was Nov. 5 at Hahnemann University Hospital in Philadelphia. The latter three patients have not been identified.
Doctors planned and practiced as best they could for the operations. The Louisville team, for instance, implanted the heart in 40 calves, three pigs and 15 cadavers. Still, Dowling said, "we had a lot of unknowns going into this."
For instance, does recharging the battery make the chest feel painfully hot? (It doesn't.) In the human heart, the left and right ventricles pump together. How would the body cope with the artificial heart's setup, which alternately pumps the left side and then the right? (Not a problem.)
Not only is it different, in some ways it is better. One of these pluses became obvious early on. Unlike a real heart, this one is totally programmable. Doctors can easily speed it up, slow it down, or order it to beat more forcefully. Need lower blood pressure? An adjustment or two and it's done.
In fact, doctors say it has potential advantages over a transplanted real heart. One is less need for medication. People with transplants must take a fistful of pills daily to suppress their immune systems to prevent rejection. That can lead to a variety of ills, including susceptibility to infection and cancer.
One of the biggest questions about the AbioCor is its durability. Transplanted hearts tend to wear out after 10 to 15 years. The longest-running versions of the latest model at Abiomed's labs have been beating nonstop for 18 months. However, they are not subjected to the stresses of being inside a moving, living human being.
Newer varieties will almost certainly last longer than the current ones, but for now, "is two years reasonable?" asks Dowling. "Probably. Five years might be stretching it." No one knows exactly how the pump will fail. Will there be warning? Maybe not. In that case, "the system stops and the patient does not survive."
A device that could wear out in two years, though, may seem better than the alternative for many people dying from heart disease. Each year, doctors perform about 2,200 heart transplants, a figure that has not budged in a decade. Many times that number could benefit, but there are not enough organs available from young, healthy victims of violent deaths.
Congestive heart failure claims about 47,000 lives annually. Most of those who need a heart _ including the five with the AbioCor _ never make it onto the waiting list for a transplant, because they are too old or have too many other health problems.
"There has to be a solution to this awful problem," says Dr. Alon Aharon of St. Louis University. "We see patients _ young, salvageable people _ who just die waiting."
A total heart replacement, however, is just one possible solution. For several years, doctors have used implanted pumps called assist devices that boost the heart's power without replacing it.
Now they are installed temporarily until a transplant is available. But tests are under way to see if they can be put in permanently, even though current models all have wires sticking out of them.
In the works, however, are assist devices that, like the AbioCor, are totally implanted. "The big question we in the field will have to decide is whether we need a total heart or just an assist device," says Dr. John Conte of Johns Hopkins University.
The cost is likely to be high, at least at first. Edward Berger, Abiomed's planning director, estimates that if the artificial heart went on the market today, it would cost between $75,000 and $100,000. But prices are likely to drop as production rises, putting the AbioCor in the same category as a mid-priced car, around $25,000 to $30,000.
As with any pricey new medical technology, some worry the artificial heart will be used too much. Dr. Clyde Yancy, a cardiologist at the University of Texas Southwestern Medical Center, notes that many victims of heart failure are not getting all the standard medicines that could help them live longer and better.
"The tragedy would be to excessively apply this technology in patients who could be treated in simpler and less expensive ways," he says.