Artificial hearts are often called TAH these days - for Total Artificial Hearts. This separates them from LVADs, which are in heavier and heavier use for heart failure patients. I'll be focusing on Abiomed's Abiocor TAH for now, because it is in phase one safety trials in end-stage heart failure patients in the USA.This puts it ahead of all other TAH devices in the United States for now. Other artificial hearts have been in development for many years, but have not yet reached human trials.Abiomed has a lot of experience in heart assist devices but this is their first - and very well planned - attempt at a replacement heart. The Abiocor TAH is designed to fit completely inside the body, with no wires or tubes poking through your skin. The AbioCor is a quiet pulsatile device. That means it moves your blood in a contract/relax rhythm just like your natural heart does, creating a pulse. The Abiocor system is:
The pumping unit weighs about 2 pounds; It has 2 ventricle chambers with valves, and a motorized hydraulic pumping system. The electronics system is implanted into your stomach area; It monitors and controls the TAH, changing the pumping speed of the heart to handle your changing activity levels.
The Abiocor uses energy from either the internal or external batteries. Since the external battery pack is small and portable, you can go places and be fairly active. The internal battery is an emergency battery. It is kept charged continuously by the external batteries. That internal battery can keep you going for 30 minutes.
Power is sent from the external batteries to the internal pump through the skin (transcutaneous), using coils. One coil is implanted inside you and the other is external. When you put the external coil over the implanted coil, power moves through your skin to the internal coil without any wires. For brief periods, you can remove the external coil (transmitter) and be free of all external parts - the internal batteries supply the power for up to 30 minutes this way.
The Abiocor TAH is made mainly of titanium and a kind of polyurethane plastic called Angioflex. This TAH doesn't really have many moving parts, and that's good. Moving parts wear out faster. Parts like the valves and membranes inside the ventricles that do move are made of Angioflex. In lab testing, this plastic has held up to beating 100,000 times a day for years. The smooth, seamless design is meant to reduce damage to blood cells passing through the pump.
In January of 2001, Abiomed got an FDA Investigational Device Exemption that allowed human trials to begin. The first trial is phase one, to make sure the device doesn't harm patients and also to be sure that it has some kind of benefit for patients, although how much benefit is not the point right now.
The Abiocor TAH was first implanted into a heart failure patient in July of 2001. It has since been implanted in a handful of other patients as well. All patients in this trial faced death in 30 days or less from heart failure without the device. Five medical centers are in the trial. They are: Brigham and Women's Hospital/Massachusetts General Hospital in Boston, Massachussetts; Hahnemann University Hospital in Philadelphia, Pennsylvania; Jewish Hospital Heart and Lung Institute in Louisville, Kentucky; Texas Heart Institute in Houston, Texas; and UCLA Medical Center in Los Angeles, California.
The Abiocor replaces your heart, so your natural heart is almost completely removed. Once it's gone, you can't get it back! The Abiocor can pump more than 10 liters of blood per minute. The pumping unit is about the size of a grapefruit, so it can only be used in average sized or larger adults. The Abiocor's "heart beat" should not be loud enough for other people to hear.
Other TAH devices are in development, and have been for years. It's a long, expensive road to human trials. The Penn State TAH can be seen here. I have seen several other TAH devices described online but details are hard to find, so I am not presenting any information about them at this time. Maybe later.
January 25, 1999 - At the University of Ottawa Heart Institute, scientists are trying to develop a successful artificial heart called the HeartSaver. The HeartSaver is about the size of a man's hand and weighs 500 grams (just over one American pound). It is called an EVAD, for electrohydraulic ventricular assist device. The device is designed to sit next to a patient's heart, and does the work of the damaged left ventricle, the heart's largest pumping chamber.
The heart institute expects to begin trials with 6 local patients for a 5-year study. About 200 heart transplants a year are done in Canada. The first version of the heart sits in a glass box in the lab and has been continuously pumping since October of 1992.
How long will it pump? How will the materials react inside the human body? The HeartSaver is now in its sixth version, each time getting smaller, quieter, and more durable. It is made of titanium and polyurethane. The turbine moves hydraulic liquid, which in turn forces blood to flow through the heart's cavity.
Power to run the HeartSaver is transmitted from a small battery-powered coil taped to the chest. Another coil is implanted beneath the skin. A patient wears a battery on a belt, which can be recharged in a wall outlet or a car's cigarette lighter.
An internal battery is implanted under the skin and used as a backup power source. By itself, it can keep the heart beating for up to an hour, to allow a person to swim or shower. With the Heartsaver, a patient will not have any wires and tubes coming through the flesh, which increase risk of infection. The HeartSaver generates a pulse, just like a human heart.
A person's implanted HeartSaver is expected to last 5 years. It would then have to be replaced. The device will probably sell for $50,000 US.
Author: Maria Bohuslawsky
Source: The Ottawa Citizen
February 1, 2001 - The FDA has given permission to Abiomed to start a trial of its implantable replacement heart, the AbioCor. The FDA granted an exemption that will allow the AbioCor to be implanted in 5 patients.
The AbioCor is meant to help patients at risk of imminent death, who cannot for some reason get a heart transplant, and cannot be helped by other available treatments. The company said its implantable replacement heart is in an advanced stage of development and is ready for human trials.
November 26, 2001 - Abiomed has received permission from the FDA to implant its artificial heart in 5 more patients. The Abiocor trial calls for 15 implants done in groups of 5. So far the device has been implanted in 5 patients.
"The first 5 AbioCor patients show that we have made significant progress toward the goal of providing meaningful life extension to end-stage heart failure patients with no other alternative," said Abiomed CEO Dr. David Lederman, "But there is much left to prove and many lessons to be learned."
Source: Reuters Health
May 30, 2000 - NIH has awarded a $4.2 million grant to researchers from Utah's LDS Hospital, the Utah Artificial Heart Institute, and MedQuest Products, to develop the HeartQuest, a new total artificial heart. The 4 year grant is the first to be given under NIH's new Bioengineering Research Partnership program.
"The HeartQuest has a rotor suspended in a magnetic field so there are no internal touching parts," Dr. Don Olsen explained. The HeartQuest will only be 30 to 40% the size of existing total artificial hearts. A prototype has been designed and assembled, and the company expects a usable device to be fully tested by 2002.
Source: Reuters Health
July 4, 2000 - A 7 year old Arizona boy received a heart transplant Monday after becoming the first patient in North America to receive a child-sized artificial heart pump. Carlos Ochoa received the heart in a 6 hour operation, and was listed in critical but stable condition. He had suffered from restrictive cardiomyopathy, a condition that caused his heart to become too stiff to pump properly.
Little Carlos had been fitted with a German-made device called the Berlin Heart on May 24. The FDA gave Dr. Jack Copeland permission to use the heart pump on an emergency basis in this case. The device, which comes in several sizes and is the only one that can be used in children, is used in Europe but its manufacturer decided that testing for approval in the USA would be too expensive. Copeland said this successful use might encourage research and testing of artificial hearts and pumps for American children.
August 27, 2001 - Patients with ICDs who get staphylococcus aureus bacteremia may have infected devices also. This risk is much higher than anyone guessed before. Researchers now estimate that about 70% of S aureus bacteremia patients who have an implanted device may also have a device infection.
Dr. Anna Chamis studied 33 patients with ICDs or pacemakers who had S aureus bacteremia over a 6 year period. Device infection was found in 15 of these patients (45%). "The majority of device infections showed no obvious signs," Dr. Chamis said.
In the 12 patients who had their device implanted within one year of infection, 9 had confirmed device infections; So did 6 patients whose device had been implanted for more than a year. Device infection was suspected in another 9 patients, but these patients died of blood poisoning before tests were completed.
Heart device infection is not always obvious, especially when the infection involves the "pocket" where the device generator is implanted. Sixty percent of the patients with confirmed device infection showed no "detectable signs of generator pocket infection," the researchers said. Neither physical exam nor an echo can definitely spot this type of infection.
In patients who get S aureus bacteremia, the device is usually involved, and 40% of these patients do show signs of infection. However, in patients who get S aureus bacteremia more than a year after device implant, the device is not usually the source of bacteremia, and there are no signs of device infection - even if the device is infected. The implanted device is involved in about 28% of these patients.
Doctors with patients who get S. aureus bacteremia should worry about device infection, Dr. Chamis said. Device infection results in increased illness and death. If the infected device is not replaced, there is increased risk of death.
If the device becomes infected, it should be replaced, Dr. Chamis said. "If the device is not infected, then the patient should get extended treatment with antibiotics. If test results are uncertain, patients should be closely followed with repeated blood testing."
Title: Staphylococcus aureus Bacteremia in Patients With Permanent Pacemakers or Implantable Cardioverter-Defibrillators
Authors: Anna Chamis, Gail Peterson, Christopher Cabell, G. Corey, Robert Sorrentino, Ruth Greenfield, Thomas Ryan, L. Reller, Vance Fowler Jr
Source: Circulation 2001;104:1029-1033
Correspondence to Vance G. Fowler, Jr, Box 3281, Division of Infectious Diseases, Duke University Medical Center, Durham, NC 27710. E-mail firstname.lastname@example.org
January 24, 2002 - Abiomed has removed a piece of their artifical heart design because of fears it may cause blood clotting in users. Deposits that can cause clotting were found on a plastic cage in the artificial hearts of 2 patients who died. As a result, the cage has been removed.
Most patients who have received an AbioCor heart have had clots removed. One of them suffered a major stroke, apparently caused by a blood clot. Doctors are concerned that the plastic cage is restricting blood flow, which could lead to clotting.
The plastic cage was created for early devices that were tested on cows. However, the cage is not needed on humans because surgeons are attaching the cuff in a place where there won't be any blockage. Lederman said. "Since we don't need it, we removed it."
The Abiomed replacement heart has so far been implanted into 6 patients who were all quickly dying of heart failure. Three have died but one has been released from the hospital, a startling advance.
Researchers also said Wednesday that they are working on a smaller version of the heart that could fit all adults. The current heart fits only about half of all men and 18% of women. The new model would be about 30% smaller than the current one.
Source: AP, Abiomed press conference
April 4, 2002 - Abiomed is slowing patient enrollment in its AbioCor artificial heart trial. However, the company said that a filing for US approval for limited patient use is still expected before the end of 2003. "Previously, we had announced that all 15 trial patients would be implanted by June 30," a company spokeswoman said. However, now she says the company is "really taking time to reflect on the previous 6 implants to ensure the success of the remaining nine."
The trial is designed to see if the AbioCor heart can double the survival time of biventricular heart failure patients who have a life expectancy of less than 30 days. To date, six patients have been enrolled in the trial. Five have actually received the AbioCor device, and 3 have died. The sixth patient died during surgery before implant.
One of the deaths may have been caused by a stroke from by a plastic cage in the device. That cage is no longer used. Three AbioCor patients have had strokes. Despite the deaths, the AbioCor has been quite successful, with 4 of 5 patients living well beyond their expected time.
Source: Reuters Health, Medscape
March 27, 2002 - Artificial heart recipient Tom Christerson was was discharged March 20, 2002, from Jewish Hospital, where he has been recovering since his implant on September 13, 2001. He is now living at The Inn at Jewish Hospital, a hotel one block from the hospital. "The rest of Mr. Christerson's routine, such as twice daily rehab and occasional lab tests, will remain the same," Dr. Gray explained. "However, he should feel less like a patient now that he's able to sleep and relax outside of the hospital."
Christerson was the second patient in the world to receive the AbioCor Implantable Replacement Heart.
April 12, 2002 - The seventh patient to get an Abiomed artificial heart died shortly after the surgery that implanted the heart.
The surgery was done Wednesday at Jewish Hospital in Louisville, Kentucky. Doctors said the patient had a long history of heart problems, was on multiple drugs to maintain blood pressure, and was on a ventilator before the surgery.
The implanted heart functioned as expected but the patient died after the surgery. All but 2 of the 7 patients receiving the heart have died: one during surgery and 3 from later complications. The FDA has authorized 15 implants for the first trial.
The company expects to present trial results to the FDA by the end of 2003, spokeswoman Sara Goldstein said. If the replacement heart gets FDA approval, it will probably be more succcessful because patients getting it would not be so near death at time of implant.
Source: Reuters Health
April 16, 2002 - A 71 year old recipient of Abiomed's artificial heart was sent home Tuesday, having survived 215 days with the device. "I've been given a second chance at life, and I can't wait to get home and begin celebrating it," Tom Christerson said as he got ready to leave for his hometown of Central City, Kentucky.
Christerson is the second recipient of the heart, which has no wiring outside the body. He has been living at a hotel close to Jewish Hospital, where the implant was done September 13, 2001. Jewish Hospital staff have been training local medical people in Central City about the heart. Christerson's car has been fitted with a charger so his heart's power supply can charge while he drives.
Source: Reuters Health
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