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Wider Use Ahead : Heart Pump: Stopgap for Emergencies

March 25, 1985|HARRY NELSON | Times Medical Writer

It was a little-noticed operation, but San Francisco surgeon J. Donald Hill was making medical history.

Last September, Hill, of the Pacific Medical Center, became the first to successfully use what doctors call a left ventricular assist device to sustain the life of a dying heart patient awaiting a human donor heart.

Hill's achievement was in part the culmination of a goal almost two decades old. It meant that a patient desperately in need of a new heart did not have to die because no heart was immediately available. Instead, an artificial pump--the result of a nationwide research effort that has taken 15 years and hundreds of millions of dollars to produce--was used as a stopgap until a transplant could be performed eight days later.

More technologically sophisticated than the Jarvik-7 artificial heart that has gained so much publicity recently, left ventricular assist devices are being touted by most heart surgeons as the wave of the future.

Aids Failing Heart

Instead of replacing the entire heart, as the Jarvik-7 heart does, the assist device is hooked to the failing heart to assist it in providing the body with a normal amount of blood flow.

Heart experts say the greatest potential use for these temporary assist devices is with patients who do not need a transplant. These include cases in which the heart goes into shock after open-heart surgery or in which it does not restart after the heart-lung machine that maintains circulation during surgery is removed.

Left ventricular assist devices have been used more than 200 times to temporarily take over the pumping function in such cases. Doctors report a 50% success rate when the device is used for this function.

As Hill's breakthrough showed, however, left ventricular assist devices can serve a second purpose: maintaining normal circulation for patients awaiting a transplant.

Within two to three years, researchers predict, several of the new left ventricular assist device designs under development will be ready for use as implantable permanent artificial hearts.

Free From Tether

One benefit, they say, is that the new devices are being designed to help free the patient from the tethering restrictions of the Jarvik-7 heart.

The emphasis on devices capable of assisting the pumping action of sick hearts is part of a new strategy by heart surgeons to deal with the estimated 100,000 people in the United States who are considered candidates for either temporary or permanent assist implants.

Most surgeons are convinced that with the exception of certain categories of patients, a human heart transplant will be preferable to even the most advanced permanent artificial hearts that they expect to see in the near future.

(Typically, a device must have two chambers in order to be considered an artificial heart. This is the case with the Jarvik-7. Because of their similar functions in pumping blood, left ventricular assist devices are also sometimes referred to as artificial hearts.)

The surgeons concede, however, that medical centers that do transplants must be prepared to also implant artificial hearts.

"Ten years ago it was a competition that led to the development of an artificial heart in some centers and heart transplantation in others," said Dr. Jack Copeland of the University of Arizona Medical Center. Today, he told reporters at a recent meeting of the American College of Cardiology, most medical centers agree that the two programs go hand in hand.

Copeland dramatized that point earlier this month when, despite not having authorization from the U.S. Food and Drug Administration for such an operation, he implanted an artificial heart in a patient whose transplanted heart had failed. The artificial device, called the Phoenix heart, was used as a bridge to keep the patient alive for 11 hours until another human donor heart could be found.

The Phoenix heart was not a left ventricular assist device, but Copeland used it for the same purpose that the assist device serves.

Surgeons have been searching for a long time for a way to keep patients alive until a donor heart arrives. This drive has been fueled by the spectacular improvement in survival of heart transplant patients over the last several years.

75% to 80% Survive

Heart transplant patients now have a one-year survival rate of 75% to 80% and stand a 50% chance of living five years.

Heart transplant experts attribute these advances in survival to better methods of selecting appropriate patients, improved post-operative care and refinements in the use of drugs that prevent rejection.

This improvement has in turn led to a greater willingness by cardiologists to refer patients to transplantation centers and greater pressure on private and government health plans to pay for transplants.

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