(Circulation. 2001;104:e9005.)
© 2001 American Heart Association, Inc.
Cardiovascular News
Circulation Newswriter
Totally Contained AbioCor Artificial Heart Implanted July 3, 2001
Surgeons from the University of Louisville have, for the first time anywhere, placed a totally implantable artificial heart in the chest of a patient in his late 50s. This event occurred on July 2, 2001, at Jewish Hospital in Kentucky and was a feat that hailed a new dawn in the development of total artificial hearts. The implantation was performed by Laman Gray, Jr, MD, and Robert D. Dowling, MD, on a patient who was said to be within a month of dying and who had been turned down for a heart transplant.
The patient underwent considerable scrutiny before the surgery was considered, said Dr Gray in a press conference held on July 4, 2001. "When he came to see us, he was extremely sick, a class IV patient . . . the sickest of the sick." The patient suffered from diabetes and impaired kidney function. Using a sophisticated algorithm, doctors predicted that the patient had no longer than 30 days to live. Next, physicians took a CT scan of the patient’s chest and heart and used a computer to determine if the pump, which is much smaller than those that had preceded it, would fit in the man’s chest.
At that point, physicians began to discuss the possibility with the patient. "We try to do this very honestly," said Dr Dowling. "We give them all the options and go over everything. We are very concerned about the ethics of doing this. For that reason, every patient entered into the study has a patient advocate." The advocates have no relationship with Abiomed, the Massachusetts company that developed the total artificial heart, or with the hospital where the procedure is performed. The advocates are also not affiliated with the medical school. The advocates serve as guides in the process and also advocate for conditions that best benefit the patient.
"For example, the patient and his family have asked that no information be released about them, and we will honor that," said Dr Dowling. "I hope everyone will respect their wishes." The patient had already suffered several heart attacks when he sought care in Louisville. At the time of the operation, he was being kept alive with a balloon pump and 3 drugs and was suffering from ischemic cardiomyopathy.
The titanium and plastic AbioCor device is about the size of a softball. Unlike previous heart pumps used in humans, this device has no wires protruding through the skin. Instead, electrical current is transmitted through the skin to a control device that regulates the rate at which blood is pumped.
Within hours of the implantation, the man had to be taken back to surgery because of bleeding. However, surgeons said that this is an expected complication given the complexity of the operation involved.
Abiomed has been extensively involved in the study of artificial hearts and also in the study of ventricular assist devices. However, in recent years, studies of total artificial hearts have fallen out of favor as new, tiny ventricular assist devices, such as those developed by Robert Jarvik, MD, and Michael E. DeBakey, MD, have gone into clinical trials and achieved prominence.
However, Abiomed has remained true to the concept of an artificial heart. The US work with the artificial organ stems from 1963, when Dr DeBakey first persuaded federal officials to fund the project. In 1969, Denton Cooley, MD, implanted an artificial heart that was very similar to the one being developed in Dr DeBakey’s laboratory, sparking a dispute between the 2 surgeons over the ownership of the device and whether Dr Cooley should have sought federal and institutional permission before the implantation. In 1981, Dr Cooley again implanted an artificial heart, this one developed by Tetsuzo Akhutsu, MD, in the chest of a Dutch bus driver.
By 1982, the federal government had come on board with the artificial heart movement, approving a heart that was developed in cooperation with Dr. Jarvik. Subsequently, an implantation in a dentist named Barney Clark took place among much media interest at the University of Utah in December 1982. However, this heart, like others, seemed associated with strokes in the patients who received it. Enthusiasm for the device waned as patients, after receiving the heart, proceeded to deteriorate in the hospital.
During this time, Abiomed and those associated with it continued to work on their artificial heart. Dr Gray said that after 2 years of animal work in Louisville (and much more such work in other centers, such as the Texas Heart Institute in Houston), the components in the complex system had been successfully completed. The information was submitted to the US Food and Drug Administration, which gave the company permission to go ahead with 5 initial implants.
The other centers designated as initial implant sites include Brigham and Women’s Hospital, Boston, Mass, which is teamed with Massachusetts General Hospital, Boston, Mass; Hahnemann University Hospital, Philadelphia, Pa; Texas Heart Institute and St Luke’s Episcopal Hospital, Houston, Texas; and UCLA Medical Center, Los Angeles, Calif. These medical centers are among the largest and most prestigious heart transplant centers in the world, and all have had significant experience working with advanced devices such as Abiomed’s BVS 5000 Bi-Ventricular Support System.
To implant the device, the surgeon removed most of the patient’s diseased heart, leaving only the left and right atria. The device was then attached to the upper chambers of the heart and to the aorta. The heart’s rhythm is maintained by a battery pack that transfers electricity across the skin to an internal coil and battery that powers the heart’s control unit. The design of the AbioCor allows its wearer to determine when the battery power is low. Because no wires penetrate the skin, the patient can take a shower and change clothes easily. Each battery is rechargeable and lasts for 4 hours, enabling a patient to be mobile.
The patient in Louisville was taken off the ventilator for about 8 hours on July 4, 2001, while family members gathered around. However, he became fatigued and needed the ventilator so that he could rest and recuperate. Hospital officials said the weakness and need for aid in breathing was to be expected.
Hospital officials said updates would be provided to the public when appropriate; this is a sharp difference from the era of Barney Clark in Utah and the subsequent use of the heart at Humana Heart Institute in Louisville in patients William Schroeder, Murray Haydon, and Jack Burcham, when press coverage became a day-to-day circus.
Battle Lines Drawn Over Patient Rights as Debate Moves to the US House of Representatives
After 5 years of battle, the US Congress is closer to passing a patient rights’ bill than ever before. However, the bill passed by the US Senate has evoked opposition from President Bush because it allows patients to sue managed care plans for malpractice.
According to the news service Reuters, the President urged the passage of a patients’ bill of rights during July. "The Congress must act on a patients’ bill of rights, a good patients’ bill of rights, one that recognizes patients are important, not lawyers," the President told a group of volunteers during a Rose Garden speech.
House leaders have said they favor a bill that would have strict limits on lawsuits, a measure that Bush is said to support.
The House bill that most closely parallels that passed by the Senate is HR 526, which is sponsored by US Representatives Charlie Norwood (R-Ga), John Dingell (D-Mich), and Greg Ganske (R-Iowa). A rival bill (HR 2315) sponsored by Rep Ernie Fletcher (R-Ky) has Republican support because the latter bill allows patients to sue health plans in state courts only when the plans refuse to follow the dictates of mandatory appeals panels. The Norwood-Dingell-Ganske bill includes a more expansive right to sue in both state and federal courts.
The Trouble With Clones
While politicians fret over the legality of human cloning, scientists warn that the technique is not a perfected as its proponents might want the world to think. In an article in the July 6, 2001, issue of the journal Science (2001;293:95–97), scientists from the Whitehead Institute of Biomedical Research in Cambridge, Mass, and the Department of Anatomy and Reproductive Biology at the John A. Burns School of Medicine at the University of Hawaii in Honolulu have found severe abnormalities of gene expression in clones.
Working in the laboratories of Rudolf Jaenisch and Ryuzo Yanagimachi, the researchers cloned mice from embryonic stem cells and monitored the activity of imprinted genes. These genes govern development and are controlled by special tags that do not affect the base sequences. They intended to see if the tags were reproduced exactly in the cloned mice and in the donor cells used to make the clones. From these data, they could tell if problems with cloning were caused by aberrations in the donor cells or by the procedure of cloning itself.
They were disturbed to determine that the donor embryonic stem cells were unstable in culture. As they divided, they lost the tags that instructed an imprinted gene to be turned on or off during development. Despite this, some of the embryos survived to adulthood, the researchers noted. "This suggests that even apparently normal clones may have subtle aberrations of gene expression that are not easily detected in the cloned animal," said Dr Jaenisch in a released statement.
Although these results are cause for concern, Dr Jaenisch said he see a real use for embryonic stem cells as therapeutic tools because it is unlikely that the imprinted cells would have a crucial role in differentiated cells.
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