Possible Donor Heart Found for Young Jarvik Recipient
A possible donor heart was found Friday in Texas for Michael Drummond, who is being kept alive with the Jarvik-7 artificial heart, a spokeswoman at the University of Arizona Medical Center said.
A medical team flew to the unidentified Texas site Friday night to determine whether the human heart is suitable for transfer into Drummond, who had recovered sufficiently Friday from a series of multiple tiny strokes to sit up and order a cheeseburger.
If the Texas heart is suitable, surgery to implant it in Drummond would begin early today in Tucson, hospital spokeswoman Nina Trasoff said.
Meanwhile, doctors at several medical centers that are conducting human and artificial heart transplants said the strokes suffered by Drummond and the three other surviving recipients of the Jarvik-7 should not be taken as a sign that the mechanical blood pump is a failure.
Clot-Dissolving Drugs
Refinements in the design of the artificial heart and new drugs that dissolve dangerous blood clots that can lodge in the brain should reduce the risks of strokes, they said. For now, they said, the Jarvik-7 heart is sustaining patients who, in the words of one heart surgeon, “would long since have been dead.”
Drummond is the first person to receive the Jarvik-7 as a temporary “bridge to transplant” rather than as a permanent replacement for a failed heart.
The condition of the 25-year-old Phoenix man had fallen to “critical and unstable” Thursday after the strokes, but he was reported as “stable” Friday by Trasoff.
Despite the improvement in his condition, Drummond was still considered a “Class 9,” or highest-priority, candidate for a heart transplant, Trasoff said. There is a continuous threat of more serious strokes as long as he remains on the artificial heart, she said.
Both William J. Schroeder and Murray P. Haydon, whose Jarvik-7 hearts were implanted in Louisville, Ky., have had strokes. Last weekend, Leif Stemberg, who received a Jarvik-7 in Stockholm, Sweden, five months ago, was similarly stricken.
According to cardiologist Eugene Braunwald, chairman of Harvard University’s Department of Medicine, clotting “is a hazard of any prosthetic device.” Blood tends to coagulate when it contacts foreign substances such as the plastic and metal inside an artificial heart.
“Clearly, there is a problem,” he said, referring to the track record of the Jarvik heart. “But we had the same problem when we first introduced heart valves years ago.”
The development of various anti-coagulant drugs, such as Heparin, allowed artificial heart valves to be implanted in thousands of patients, lengthening many lives, Braunwald said. New drugs that destroy clots without severe side effects will improve results for the artificial heart, he added.
Heparin is being used to keep Drummond’s blood from clotting, according to his surgeon, Dr. Jack Copeland. But Drummond’s unusually quick recovery from the Aug. 29 operation caused his liver to produce more clotting agents than expected, taking the surgical team by surprise on Wednesday. Small clots traveled to several parts of Drummond’s brain, causing the stroke.
Copeland’s team took several steps Friday to reduce the risk of further strokes, Trasoff said. The dosage of Heparin was increased, and another anti-clotting drug called Dextran was administered; extra fluid is being introduced intravenously to thin Drummond’s blood, and the pumping rate of the heart has been increased, to push more blood to his brain.
William Grigg, a spokesman for the Food and Drug Administration, said that the risk of stroke associated with the Jarvik heart was known before the agency granted permission to use it.
Side Effect Foreseen
“Long ago, before the first one was even implanted, it was anticipated that this might be one of the potential side effects,” Grigg said. “For one thing, artificial heart valves themselves increase the likelihood of blood clots--that’s one of their principal liabilities.”
Dr. Denton Cooley, chief of surgery at the Texas Heart Institute, who has performed more than 60,000 heart operations, said Friday that he is not discouraged by the clotting problem. As long as indicators of clot formation are frequently monitored, clots can be prevented, he said. Copeland’s team “was doing so well they may have been lulled into complacency,” he added.
Cooley foresees a need for a variety of mechanical devices to assist or replace the heart. Willem Kolff, director of the Institute for Biomedical Engineering at the University of Utah and the first man to build an artificial heart, in 1957, said that new types of valves for the Jarvik heart may reduce the frequency of clot formation.
