Artificial heart
An artificial heart is a device that replaces the heart. Artificial hearts are typically used as a bridge to heart transplantation, but ongoing research aims to develop a device that could permanently replace the heart when a transplant—whether from a deceased human or, experimentally, from a genetically engineered pig—is unavailable or not viable., there are two commercially available full artificial heart devices; both are intended for temporary use for patients with total heart failure who are awaiting a human heart transplant.
Although other similar inventions preceded it from the late 1940s, the first artificial heart to be successfully implanted in a human was the Jarvik-7 in 1982, designed by a team including Willem Johan Kolff, William DeVries and Robert Jarvik.
An artificial heart is distinct from a ventricular assist device, which may also be a permanent solution, or the intra-aortic balloon pump – both devices are designed to support a failing heart. It is also distinct from a cardiopulmonary bypass machine, which is an external device used to provide the functions of both the heart and lungs, used only for a few hours at a time, most commonly during cardiac surgery. It is also distinct from a ventilator, used to support failing lungs, or the extracorporeal membrane oxygenation, which is used to support those with both inadequate heart and lung function for up to days or weeks, unlike the bypass machine.
History
Origins
A synthetic replacement for a heart remains a long-sought "holy grail" of modern medicine. The obvious benefit of a functional artificial heart would be to lower the need for heart transplants as the demand for organs always greatly exceeds supply.Although the heart is conceptually a pump, it embodies subtleties that defy straightforward emulation with synthetic materials and power supplies. Artificial hearts have historically had issues from both a biomedical standpoint, regarding clotting and foreign object rejection, as well as longevity and practicality, regarding the lifespan of the device as well as the equipment required to run it.
Since the inception of the device, artificial hearts have been continually improved as medical technology has. More recent devices, such as the Carmat heart, have sought to improve upon their predecessors by reducing complications resultant from device implant, such as foreign-body rejection and thrombus.
Early development
The first artificial heart was made by the Soviet scientist Vladimir Demikhov in 1938. It was implanted in a dog.On 2 July 1952, 41-year-old Henry Opitek, suffering from shortness of breath, made medical history at Harper University Hospital at Wayne State University in Michigan. The Dodrill-GMR heart machine, considered to be the first operational mechanical heart, was successfully used while performing heart surgery.
Ongoing research was done on calves at Hershey Medical Center, Animal Research Facility, in Hershey, Pennsylvania, during the 1970s.
Forest Dewey Dodrill, working closely with Matthew Dudley, used the machine in 1952 to bypass Henry Opitek's left ventricle for 50 minutes while he opened the patient's left atrium and worked to repair the mitral valve. In Dodrill's post-operative report, he notes, "To our knowledge, this is the first instance of survival of a patient when a mechanical heart mechanism was used to take over the complete body function of maintaining the blood supply of the body while the heart was open and operated on."
A heart–lung machine was first used in 1953 during a successful open heart surgery. John Heysham Gibbon, the inventor of the machine, performed the operation and developed the heart–lung substitute himself.
Following these advances, scientific interest for the development of a solution for heart disease developed in numerous research groups worldwide.
Early designs of total artificial hearts
In 1949, a precursor to the modern artificial heart pump was built by doctors William Sewell and William Glenn of the Yale School of Medicine using an Erector Set, assorted odds and ends, and dime-store toys. The external pump successfully bypassed the heart of a dog for more than an hour.On 12 December 1957, Willem Johan Kolff, the world's most prolific inventor of artificial organs, implanted an artificial heart into a dog at Cleveland Clinic. The dog lived for 90 minutes.
In 1958, Domingo Liotta initiated the studies of TAH replacement at Lyon, France, and in 1959–60 at the National University of Córdoba, Argentina. He presented his work at the meeting of the American Society for Artificial Internal Organs held in Atlantic City in March 1961. At that meeting, Liotta described the implantation of three types of orthotopic TAHs in dogs, each of which used a different source of external energy: an implantable electric motor, an implantable rotating pump with an external electric motor, and a pneumatic pump.
Paul Winchell designed a model of artificial heart with the assistance of Henry Heimlich and submitted a patent for a mechanically driven artificial heart implementing a cam driven roller mechanism to compress flexible bags containing blood, on 6 February 1961. This is contrary to the popular claim that Winchell submitted the patent in the summer of 1956, as well as contrary to the claim that Winchell "invented" the artificial heart. In fact, two patents existed prior to Winchell's submission. These patents were filed 10 April 1956, and 17 April 1959, respectively. Winchell also claims that the design within his patent was used in later models of the Jarvik hearts, a claim in which Robert Jarvik, the principle designer of those hearts, denies on the basis that his pneumatically driven hearts share little in common with Winchell's mechanically actuated patent.
In 1964, the National Institutes of Health started the Artificial Heart Program, with the goal of putting an artificial heart into a human by the end of the decade. The purpose of the program was to develop an implantable artificial heart, including the power source, to replace a failing heart.
In February 1966, Adrian Kantrowitz rose to international prominence when he performed the world's first permanent implantation of a partial mechanical heart at Maimonides Medical Center.
In 1967, Kolff left Cleveland Clinic to start the Division of Artificial Organs at the University of Utah and pursue his work on the artificial heart.
- In 1973, a calf named Tony survived for 30 days on an early Kolff heart.
- In 1975, a bull named Burk survived 90 days on the artificial heart.
- In 1976, a calf named Abebe lived for 184 days on the Jarvik 5 artificial heart.
- In 1981, a calf named Alfred Lord Tennyson lived for 268 days on the Jarvik 5.
First clinical implantation of a total artificial heart
On 4 April 1969, Domingo Liotta and Denton A. Cooley replaced a dying man's heart with a mechanical heart inside the chest at The Texas Heart Institute in Houston as a bridge for a transplant. The man woke up and began to recover. After 64 hours, the pneumatic-powered artificial heart was removed and replaced by a donor heart. However thirty-two hours after transplantation, the man died of what was later proved to be an acute pulmonary infection, extended to both lungs, caused by fungi, most likely caused by an immunosuppressive drug complication.The original prototype of Liotta-Cooley artificial heart used in this historic operation is prominently displayed in the Smithsonian Institution's National Museum of American History "Treasures of American History" exhibit in Washington, D.C.
First clinical applications of a permanent pneumatic total artificial heart
The first clinical use of an artificial heart designed for permanent implantation rather than a bridge to transplant occurred in 1982 at the University of Utah.In 1981, William DeVries submitted a request to the FDA for permission to implant the Jarvik-7 into a human being. On 1 December 1982, William DeVries implanted the Jarvik-7 artificial heart into Barney Clark, a retired dentist from Seattle who had severe congestive heart failure. Clark's case was highly publicized and received much media attention, garnering attention from television networks, newspapers and periodicals. Clark lived for 112 days tethered to the UtahDrive pneumatic drive console, a device weighing some. During that time Clark required several re-operations, suffered seizures, experienced prolonged periods of confusion and a number of instances of bleeding and asked several times to be allowed to die. Clark, however, still believed his being part of the initial experiment was an important contribution to medicine, and maintained an overall positive outlook on his condition. Barney Clark died on 23 March 1983, of multiorgan system failure. Despite the complications, DeVries considered Clark's case a success.
DeVries subsequently moved his practice to Humana Hospital Audubon in Louisville, Kentucky to continue studies using the Jarvik-7. DeVries' first artificial heart patient in Louisville was Bill Schroeder. DeVries replaced Schroeder's failing heart with a Jarvik-7 on 25 November 1984. Like Clark, Schroeder suffered from bleeding that required re-operation to resolve. In the first weeks the outlook was good and Schroeder was allowed to have a can of Coors beer and he was given a phone call by President Reagan, in which he famously asked the president for an update on a late Social Security check. However, 19 days after the operation, Schroeder suffered the first of four strokes. Despite this, his recovery continued and was allowed to live in a specially outfitted apartment near the hospital for a period of time, as well as use a newly developed battery-powered portable drive unit for the heart which allowed him to venture out of the hospital for short periods. Schroeder's health continued to decline as three more strokes plagued his time with the artificial heart. He died on 6 August 1986, from complications from a stroke, respiratory failure and sepsis, after 620 days with the artificial heart.
Three more patients received the Jarvik-7 as a permanent heart. Murray Haydon, DeVries' third patient, received a Jarvik-7 on 17 February 1985. Haydon suffered pulmonary issues and was required to be on a mechanical ventilator for the duration of his time with the artificial heart. Haydon died of infection and kidney failure on 19 June 1986, after 488 days with his artificial heart. On 7 April 1985, Dr. Bjarne Semb of Karolinska Hospital in Stockholm, Sweden implanted a Jarvik-7 in Swedish businessman Leif Stenberg. Stenberg lived 229 largely uneventful days with the heart, but suffered from a stroke and subsequently died on 21 November 1985. Jack Burcham was DeVries' fourth and final patient to receive a Jarvik-7 as a destination therapy. Burcham received his heart on 14 April 1985, but due to complications from the size of the device, bleeding and kidney failure, Burcham died just 10 days later on 25 April 1985.
In the mid-1980s, artificial hearts were powered by large pneumatic drive consoles. Moreover, two sizable catheters had to cross the body wall to carry the pneumatic pulses to the implanted heart, greatly increasing the risk of infection. To speed development of a new generation of technologies, the National Heart, Lung, and Blood Institute opened a competition for implantable electrically powered artificial hearts. Three groups received funding: Cleveland Clinic in Cleveland, Ohio; the College of Medicine of Pennsylvania State University in Hershey, Pennsylvania; and AbioMed, Inc. of Danvers, Massachusetts. Despite considerable progress, the Cleveland program was discontinued after the first five years.