Plug-In Heart Pump

Doctors all too often perform open-heart surgery that is technically perfect only to have the patient die soon after the operation, because his previously weakened heart cannot bear the added burden of surgical shock. To ease the load on ailing hearts, doctors have for several years used implantable balloon pumps (TIME, Aug. 23, 1971) and other devices that are designed to be removed surgically after recovery. A system developed at Manhattan's Mount Sinai Medical Center carries this heart-assist technology a significant step forward. Their pump not only provides a postoperative boost but can be connected again without major surgery if the patient suffers a relapse.

Dr. Robert S. Litwak and his colleagues at Mount Sinai designed the new system to meet two requirements: 1) it had to relieve the left ventricle, the heart's main pumping chamber, of as much as three-quarters of its work load, and 2) it had to remain in place in case it should be needed again. The system they devised is installed while the patient is still hooked up to the heart-lung machine, which takes over the function of these organs during open-heart surgery. First Litwak and his team insert two cannulae, or tubes, of flexible silicone into the patient's open chest. One tube is stitched into his left atrium, to draw off blood before it reaches the ventricle (see diagram). The second tube is connected to the aorta, to return pumped blood to general circulation. The tubes are then led down through the surgical incision in the chest and placed under the skin of the upper abdomen.

When the tune comes to take the patient off the conventional heart-lung machine and close his incision, the ends of the tubes are connected to a simple roller pump. The pump draws oxygenated blood from the left atrium and injects it forcibly into the aorta. The first time the system was used, the pump was doing 65% of the heart's work three hours after the operation. By the fifth hour, the heart had recovered sufficiently to perform 50% of its normal function. By the twelfth hour, the heart was carrying 78%, and by the 42nd hour, 95% of the work. The pump was unhooked 44 hours after the operation.

To make reinstallation easy, silicone plugs were inserted in the openings of the tubes; a flap of skin was closed over the ends. Litwak's first patient and four subsequent ones are now home recovering from their operations, their hearts working at full capacity. Furthermore, they may be better protected than most heart patients against a relapse. If their hearts need some help in the future, all Litwak should have to do is make a simple skin incision and reconnect the pump. The plumbing is still in place.

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