Medicine: Bridging the Gap: A new role for artificial hearts

In Pittsburgh, Thomas Gaidosh, 47, a burly, 6-ft. 3-in. factory worker and father of two, languished in his hospital bed last month, struggling for his life. For weeks, doctors at Presbyterian-University Hospital had been searching for a donor heart to replace his debilitated one. Time was running out. Across the state, in the chocolate capital of Hershey, Anthony Mandia, 44, was losing a similar battle. Mandia, a Philadelphia recreation-center director, had a history of coronaries, and now his heart was deteriorating rapidly, but no donor could be found. On the West Coast, Richard Dallara, 33, an auto mechanic from Sonoma, Calif., was near death, also awaiting a donor heart. Then, within one week, all three became willing subjects in the newest medical experiment in borrowing time: the use of a mechanical pump as a temporary “bridge” to a human-heart transplant.

Last week they appeared to have safely crossed that bridge. Within hours of one another, the three men underwent surgery to replace their temporary mechanical devices with donor hearts. At week’s end all seemed to be making progress, and none showed signs of rejection.

The flurry of surgery marked an important transition in the use of artificial hearts. After the serious neurological complications in such earlier mechanical-heart recipients as Barney Clark, Jack Burcham and William Schroeder (who remains alive but brain-impaired after nearly 350 days with the Jarvik-7), the tide seems to be turning away from the use of artificial pumps as permanent fixtures. Instead, surgeons are beginning to implant them as emergency stopgap measures. This change of emphasis became apparent at a meeting in Washington last month attended by most of the world’s leading implant surgeons. Several felt that the artificial heart, in its current form, is simply too crude and too risky to be widely used on a long-term basis. Tucson Surgeon Jack Copeland, who helped pioneer the use of an artificial heart as a temporary measure, judged the Jarvik-7 “a monstrous thing that does awful things to people.” The longer it remains in a patient, he said, “the more likely you’re going to have trouble.”

Used as a bridge, the mechanical heart is kept in place until the patient’s condition stabilizes and a donor organ is found. Surgeons can now choose among several types of pumps. While Gaidosh received the familiar Jarvik-7, Mandia’s surgery marked the debut of the Penn State heart, developed by Surgeon William Pierce of the Milton S. Hershey Medical Center. It has been approved by the Food and Drug Administration for temporary use only and is designed to overcome the blood-clotting problems that have plagued Jarvik-7 recipients. Dallara, meanwhile, was connected to a pair of external pumps called ventricular assist devices, which are ordinarily used singly to help heart patients recover after surgery. When used in pairs, VADs can take over the work of both the left and the right pumping chambers and serve as a complete artificial heart.

Many surgeons are optimistic about the use of mechanical hearts as bridges. Under ideal conditions, once the artificial heart is replaced by a human donor heart, a patient’s prospects should be roughly similar to those of other transplant recipients: an 80% chance of survival for at least one year, 60% for five years. There is, however, an ethical concern: patients with mechanical hearts may be given priority over others waiting for donor hearts, which are in desperately short supply.

In the long run, some sort of permanent artificial implant will almost certainly be necessary if the growing demand for replacement hearts is to be met. The early efforts of Surgeon William DeVries with the Jarvik-7 and the new work with bridge implants have already suggested ways of improving today’s crude devices. In the future, says Pierce, “they’ll seem to us like the Model T.” Down the road, he hopes, lies the cardiac equivalent of a well-tuned Mercedes.