Will that 40-year-old really be a typical artificial heart recipient? Opinions differ. Mehmet Oz, a surgeon at Columbia Presbyterian Medical Center, thinks the device will find a much more limited role, primarily as a replacement when a transplant recipient rejects a donated heart and isn’t eligible for another. Others are even less optimistic. “I have some doubts about how well it will do as a permanent implant,” says DeBakey. “History tells us this is very difficult.”
Whatever their degree of skepticism, all observers agree that only human tests will yield answers. Lederman has promised tests on people will begin before the end of next year. As TR went to press, however, Abiomed engineers were still tweaking the heart’s final design; the FDA will require Abiomed to run some 12 to 20 units in the lab for up to one year with few or no mechanical failures before human studies can get under way.
And though Abiomed’s animal tests look promising, the transition from healthy calves to sick humans presents many unknowns, says Richard Smith, head of the artificial heart program at the University of Arizona. How will human skin react to the electricity-conducting coils, for example? “We are going to have to learn the way we always have learned-which is the hard way,” Smith says.
That view is widely shared, and Alan Snyder, who heads the engineering team working on Penn State’s heart, warns that the public should have realistic expectations. He notes that even patients who have had only one heart valve replaced with a mechanical substitute have some chance of stroke. With four synthetic valves, he says, “you have to realize that things will happen to these patients that we wish wouldn’t.”
At Abiomed, Lederman continues to do all he can to make history without repeating it. But no amount of technical care or ethical caution, advisory boards or media test cases can say for sure how the PulsaCor will fare in human testing. “Sooner or later,” Frazier says, “we will have to move forward with some uncertainties still.”