Earlier this summer Robert Imhausen won one horseshoe tournament and placed second in another–not bad for a 67-year-old guy whose doctor told him last fall he would be dead in six months.
Imhausen survives with the aid of an experimental device implanted in his body to help his heart pump blood to his organs. He is one of dozens of heart failure patients whose life has been extended by some version of an artificial heart.
Surgeons have been experimenting with artificial hearts for nearly 50 years, and despite many failures and a few successes, they continue to pursue developing a device to assist or even replace a failing heart and provide the patient with years of a life worth living.
An estimated 4.8 million Americans have congestive heart failure, with some 400,000 new cases diagnosed annually. Each year heart failure is directly responsible for 42,000 deaths and is related to the cause of death in another 219,000 cases, a study from the Centers for Disease Control and Prevention estimates.
Artificial hearts and left ventricular assist devices, or LVADs, represent cardiology’s most aggressive technology, sometimes serving as a bridge to a heart transplant, but often seeking to help patients for whom no transplantable heart is available.
Artificial hearts and LVADs replace or bolster failing heart muscle. That is more ambitious than implanted pacemakers and defibrillators, which use technology to correct faulty heartbeats.
Yet even though pacemakers and defibrillators have been approved for widespread use for years, their makers still encounter difficulties and must recall the devices at great expense.
So why do physicians persist in pursuing the more difficult, riskier technology of artificial hearts?
“The reason we all keep after the problem is that the patient has no alternative. Just death,” said Dr. Valluvan Jeevanandam, the University of Chicago heart surgeon who implanted the pump that helps keep Imhausen’s blood flowing.
While some drugs help to make patients feel better, they cannot reverse the underlying problem in heart failure, which is that a person’s heart muscle no longer has enough power to pump blood to nourish all the body’s organs, Jeevanandam said.
Studies have shown that artificial pumps can provide better results than medications, but the pumps have shortcomings that add up the longer they operate. Patients may develop infections or suffer strokes. And wear and tear causes parts to fail with each passing month of operation.
The device Jeevanandam uses seeks to avoid these shortcomings. All its moving parts operate outside the body.
An electric pump the patient wears on a vest moves air in and out of a balloon implanted on the patient’s aorta–the big artery that carries blood away from the heart. This inflating and deflating balloon works in concert with the heart’s normal rhythm to suck blood out of the heart as the heart muscle contracts to pump blood.
This design has many advantages, said Jeevanandam, who has no financial interest in the company that makes the device, L-VAD Technology Inc. of Detroit.
Also, if the patient wants to turn off the device, called the CardioVADII, he can do so without fear of dire consequences.
Indeed, this happened with Imhausen, a Portage, Ind., retiree, when his pump stopped working. He took it to the University of Chicago Hospitals, where technicians fixed it.
“I don’t have to worry,” said Imhausen, who received his pump in February. “If anything happens to the machine, I know I can survive until they fix it up. Now I have things to look forward to. Before, I had nothing to look forward to.”
The first version of the CardioVAD was implanted in a patient in 1966. The first patient died almost immediately, and the second patient lived less than two weeks.
“But we had evidence that we could take a patient out of heart failure,” said Dr. Adrian Kantrowitz, founder of L-VAD Technology. Kantrowitz’s design eventually was used to produce an assist device intended to help patients with short-term heart failure, and it has been commercially available for years.
Creating a device suitable for long-term use has been Kantrowitz’s lifelong quest. Once the University of Chicago gets four or five patients implanted with CardioVADIIs the technology may be ready for the kind of large trial needed to win approval from the federal Food and Drug Administration.
That would require treating about 100 patients at several institutions to demonstrate the efficacy of the pump. That would cost millions. Before undertaking such an ambitious trial, Kantrowitz said, he will need to get new management for his company and attract funding from venture capitalists.
Kantrowitz is a caring physician and gifted device designer, “but he’s no businessman,” said Jeevanandam. “Adrian will not go forward with an implant unless he is convinced it is the best possible device he can produce.
“Unlike other companies, L-VAD Technology is very responsive to patient outcomes. Adrian’s attitude, however, has slowed down the company, but I feel it will produce the best possible device for patients.”
Several other heart pumps are much closer to FDA approval. The HeartMate II Left Ventricular Assist System from Thoratec Corp. is one product already launched in a large, multi-institutional study.
Unlike conventional pumps, the HeartMate II is a rotary mechanism with one moving part that weighs about 14 ounces and is just a little more than 3 inches long.
The small size and simplicity of the HeartMate II are advantages, said Dr. Rohinton Morris, surgical director of the heart transplant program at the University of Pennsylvania hospital, where the device is being implanted.
The lack of pulsation in moving blood poses questions, said Morris. “Nobody knows in the long term what this means for the kidneys, the brain, what it means for someone who wants to exercise.”
The test requires results from hundreds of patients and takes two years before researchers will know the optimal use for the device, Morris said.
“All these things are experimental,” he said. “If these were developed and one just worked beautifully, everybody would use it.”
While the current crop of heart pumping devices all have some drawbacks, Jeevanandam said that third- and fourth-generation devices now on the drawing boards will take advantage of what has been learned.
These new devices not only promise fewer side effects, but they will also be easier to install or remove, he said.
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jvan@tribune.com
