By Anne Bennett
A diagnosis of heart failure once signaled imminent death. Today, specialists are abuzz with pacers, pumps and other implantable mechanisms that have changed the picture for patients with this lethal condition.
There is no cure for heart failure. Half the people diagnosed with it
will be dead within five years. The heart gradually loses its ability
to pump blood; the victim feels a deadening fatigue, struggles to breathe,
and the lungs become congested with fluid. Luckily for most people with
the disease, drug therapy is hugely helpful. But for those who don't respond
to drugs or for some unknown reason stop responding there has been little
aside from a transplant to make the damaged heart function effectively
In the last months of 2000, Hopkins joined a multicenter clinical study called companion (Comparison of Medical Therapy, Pacing and Defibrillation in Chronic Heart Failure) to assess how heart-failure patients fared on the bi-ventricular pacemaker in comparison with other kinds of treatment. Every patient in the study, like Jim McCormick, had a heart with an electrical-conduction disturbance-a "dysynchronous" heart. The patients had been divided into three groups. One group would be treated with medication alone; the other two would receive medication plus one of two possible bi-ventricular devices that would keep the heart beating in sync.
What Jim McCormick needed was resynchronization, and he prayed he wouldn't be relegated to the number one group. "I knew there was a chance the bi-ventricular pacing device might not help me," he says, "but if it did, I felt sure it could extend my life until I got a transplant."
On Nov. 27, 2000, McCormick had a physical exam to qualify for the trial. Three days later, he learned he'd made the cut and would be part of the second group. And so, on Dec. 4, he found himself being wheeled into the Hospital's busy electrophysiology lab where electrophysiologist Ronald Berger was preparing to implant a bi-ventricular pacer in him.
Much of the early work on bi-ventricular pacing was led at Hopkins by David Kass, a heart failure basic researcher who also is in the Department of Biomedical Engineering. Berger was part of Kass's team of researchers. Back in the mid-1990s, he and Kass were doing all sorts of experiments with standard pacemakers, trying to figure out how to pace the left ventricle. Their most significant study confirmed that bi-ventricular pacing improves the heart's efficiency. "We showed how the cardiac muscle uses less oxygen with the pacing despite the fact that it's pumping more blood," Berger says.
Still, for all its glory, the bi-ventricular pacer remains technically challenging for the electrophysiologist. For a long time, Berger was the only one at Hopkins who could put the device into a patient. Even today, he does more than 90 percent of the implants. The procedure, which is done with sedation and a local anesthetic, is not particularly risky, but the cardiologist must stand for long periods, often in awkward positions, clad in a weighty lead vest and wrap-around skirt that acts as a barrier to the radiation emitting from the imaging devices.
As the dilated, baggy heart thumped away, Berger began traveling along the wispy streets and alleys that come off the coronary sinus, dodging dead ends, navigating hairpin turns, heading for a branch that would take him as far out to the side as possible. And because negotiating these turns is the hardest part of the procedure, his eyes almost never left the monitor which showed him in vivid images how far he'd progressed into the heart. Reaching a destination he deemed suitable, Berger inserted the lead into the sheath and over the guide wire and poked it all the way out to the left ventricle outpost. Then he pulled out first the guide wire and then the delivery sheath, leaving the lead in place on the ventricle. Finally, he positioned the two other leads in the right atrium and right ventricle. The pacing could now begin.
"These new pacers benefit only a small group of heart-failure patients," Hare says. "But even though they now are FDA-approved, we know far less about them than we do about drugs. What we do know is that they make patients feel better."
McCormick stands as living testimony to that. Immediately after the procedure, in the recovery room, he already felt "strangely refreshed." Today, a year and a half later, his name remains on the transplant list, but "I have a certain quality of life," he says. "I can't plant a tomato garden, but I can tend one. I can't cut the yard, but I can pull a few weeds. I can't talk for hours, but I can still enjoy the company of friends." As part of companion, McCormick comes for quarterly checkups-he considers it a duty. He hopes that aside from prolonging his life, the device "can teach doctors something about how to help others like me who are waiting for a new heart."
That waiting, of course, remains one of the biggest problems of all. The generally accepted medical therapy for the late stages of heart failure is a transplant. But of the approximately 56,000 people annually who need a new organ, only about 2,000 will be lucky enough to receive the call telling them a donor heart has become available. Most of the rest will die. That's why cardiac specialists have begun resting their hopes on the idea of a workable artificial heart.
Some 125,000 Americans a year could be candidates for an implantable
artificial heart. The new AbioCor replacement heart, currently in several
small, FDA-authorized clinical trials and first implanted in a patient
in Louisville, KY., in the summer of 2001, is a small battery-driven pump
about the size of a grapefruit and weighing two pounds. How soon the AbioCor
becomes available on an experimental basis at Hopkins, however, will depend
on the manufacturer and what modifications it chooses to make. "I
expect to be putting it in as soon as we get it," says Edward Kasper,
medical director of the heart failure/heart transplant program. "But
that could be two years from now, or as early as the fall."
LVADs, of late, have been proving their mettle. A landmark study published last November found that they kept heart-failure patients alive longer than optimal medical therapy and offer them an improved quality of life. They may even be able to provide an acceptable alternative therapy for heart-failure patients who aren't candidates for transplantation.
Fortunately for Riddle, his ample torso easily accommodated the LVAD. Once he was fitted with the device, he did well for a full year. "We went on errands, picnics in the park. He even went fishing," his wife Rosa recalls. Then, early in the afternoon last March 26, while Rosa and he were sitting in the den of their Columbia, Md., home, the LVAD's alarm went off, meaning that the pump had either slowed or stopped. Steve's feeble heart may have actually pumped on its own for the minute or two it took him to change the batteries and check the alarm. Nothing helped. The pump refused to pump, and Steve passed out.
Rosa grabbed for the hand pump that Albaugh had taught her to use. Panic-stricken, she pumped and nudged her husband, pumped and nudged, calling Steve's name over and over. Gradually, he came to, and as Rosa continued to pump, Steve even dialed 911 and lucidly gave the dispatcher the vital information. All the way into the Hopkins emergency department, the EMTs pumped Steve. At Hopkins, doctors discovered the LVAD had an electrical problem.
"I never thought this would happen," Rosa says bitterly. For her and Steve, the big hurdle to get through had been finding a donor heart. The mechanical failure had been an unanticipated roadblock.
The only safe place now for Riddle and his malfunctioning device was a hospital bed. Four months, as his name stood at the top of the transplant list, he lay tethered to a pneumatic pump that required round-the-clock surveillance. But coming up with a donor heart that matched Riddle's substantial size was not easy. By July, cardiologists were thinking about implanting a second LVAD. But Riddle held out, praying a heart would come through. On the night of July 13, cardiac surgeon Peter Greene walked into his room."We've got a heart," he said. "Do you want it?" Early the next morning, Greene began the transplant.
"We are on the precipice of some big advances," says Conte, who's surgical director of the heart failure/heart transplant program. "Once the problems of the earlier devices are corrected-and that's just a matter of time-VADs will become permanent for some patients-alternatives and not bridges to transplant. When LVADs become fully implantable, Conte says, they may be more cost effective than transplants. "Down the road, they may even render heart transplants a thing of the past."
There will be a price to pay if more physicians begin implanting LVADs or one of the new pacing devices in patients. Each of these devices costs tens of thousands of dollars. An LVAD like the one Riddle had, for example, goes for around $50,000. Such costs are fueled by a number of sources-the desperate hopes of dying patients, commercial interests of medical equipment manufacturers, institutions striving to offer the latest in medical technology and, perhaps most of all, by physicians laboring to keep dying patients alive. "We are not at the point yet where we can cure congestive heart failure, even though we've made great strides," says cardiologist Hare. "These devices offer tremendous opportunities for stabilizing patients and preventing them from dying. For that we feel extremely lucky."
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Stents of a New Stripe
Most people don't think of clogged coronary arteries as having anything
to do with heart failure. But, in fact, cardiologists say that the earliest
stage of the condition occurs when fat deposits begin to seriously block
the blood flow to the heart. And so, they have come up with inventive
ways to keep the vital coronary blood vessels open. What's been a challenge
is to keep them from clogging up again.
Much of the early work on these so-called drug-eluting stents was done
by Hopkins interventional cardiologist Alan Heldman and researchers at
the Gerontology Research Center of the National Institute on Aging, located
on the Johns Hopkins Bayview campus. Using paclitaxel, the active ingredient
in the drug Taxol®, the scientists tried to affix the drug to the
stent in several different ways. Ultimately, they settled on what Heldman
describes as the simplest approach: "We just got the bare-naked drug
on the bare-naked stent."