Assist for an Ailing Heart

Though a growing number of surgeons are learning how to transplant hearts, the operation seems destined to remain a rarity because donors are scarce and the problem of tissue rejection is still unsolved. Therefore, researchers have been working for more than a decade to develop an implantable artificial heart. Last week, Dr. Adrian Kantrowitz, the surgical pioneer who performed the first heart transplant in the U.S., moved the effort a significant step forward. In Detroit's Sinai Hospital, he put an artificial heart booster into the chest of Haskell Shanks, 63, whose heart was so weakened that it could not pump enough oxygenated blood to his body.

The operation was hardly the first attempt to use an artificial heart device in humans. Dr. Michael DeBakey has tried temporary pumping mechanisms on eight patients, two of whom are still alive. Kantrowitz has twice installed permanent heart pumps in patients, one of whom survived for 13 days. But last week's operation differed from the previous ones. Kantrowitz's new pump is not only more advanced than earlier assist mechanisms, but because of a specially developed inner coating, it is less likely to trigger the blood-clotting problems that plagued earlier implants. Therefore it has a better chance of remaining in the patient indefinitely. Hence it could offer new hope for patients with intractable congestive heart failure.

Cigar Shape. Described as a patch booster, the pump is an improved model of the device developed in 1966 by Kantrowitz and his brother Arthur, a physicist. Made of silicone rubber and Dacron, the booster is deceptively simple in construction. Six inches long and shaped like a cigar, it consists of two tubes, a balloon-like outer bladder surrounding a narrow tube, with an air hose that leads from the outer tube to a helium-powered driving unit and compressed air tank outside the body.

Installation of the pump was intricate business. Shanks, who was near death, was wheeled into the operating room at 7:15 p.m. Doctors opened his chest and slit the descending aorta, the downward trunk of the main artery leading from the heart. They then sewed the booster directly into the aorta, led the air hose out through the chest and connected it to the exterior tank. The procedure took five hours, but it was not until 5 a.m. that Shanks left the operating room; Kantrowitz kept him there until he was certain that the booster was doing its job.

It did just that. A regulator unit connected to the heart muscle by wires kept the external pump in phase with the internal organ. As the heart's left ventricle, or major pumping chamber, contracted to force blood through the aorta, the external pump sucked air out of the outer tube, creating negative pressure that helped pull the blood out of the ventricle. Then, as the ventricle relaxed, the pump forced air back into the outer tube, increasing the pressure on the inner passage and forcing the blood through the aorta to the body.

Shanks' heart was relieved of at least half the work of supplying blood to his body. Only hours after the operation, he was doing well. But Kantrowitz believes that no heart operation is a success until the patient returns home. Shanks is not yet ready for that.

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