The concept of an implantable artificial heart that can drive circulation rhythmically and ensure the functioning of all other organs was there even before the advent and development of the modern heart-lung machine and other circulatory assist devices. The ultimate goal is to have a better quality of life and enjoy the outdoors in an unencumbered, hassle-free, and independent way with minimal gadgetry accompaniments. The main problems the researchers encountered were --
1. Size of the device - customization is cost-oriented,
2. The pump, an electromechanical gadget, has to be leakproof with no contact either with the circulation inside or interstitial fluid (third space fluid) outside,
3. Flow within and to the body vascular conduits have to be unidirectional with prosthetic valves interposed at appropriate positions so that the normal circulatory pattern is mimicked,
4. The weight of the device should be comfortable for the patient and the biomaterials used resist clot formation,
5. Situational, emotional, and organ-specific circulation has to be accounted for and a balance between the left and the right ventricular output, depending upon respective systemic and pulmonary vascular resistances, is important.
My interest in implantable artificial hearts was rekindled when I became engrossed in the practice of heart transplantation. I realised --
1. Donor heart is rare.
2. The transplant group has to have a pool of patients of all the known blood groups requiring transplantation to maximise the chances of tissue matching.
3. The whole transplant process is complex and pre-transplant vaccinations, tissue matching, lifelong immunosuppressive therapy, and periodic monitoring are all time-consuming and require hospitalisation when needed.
At that time, in addition to the usual departmental work and the transplant programme, I was also doing collaborative work with Dr. Sourabh Bhunia, who was in Minnesota (Minneapolis) as a senior scientific officer for Medtronic Inc. We were trying to develop a low-cost leadless epicardial pacemaker that could be introduced and positioned intra-pericardially by a minimally invasive technique. Sourabh was flying to Kolkata at that time I was awed to know for the first time that he happened to be one of the two mechanical engineers inducted into a project by Abiomed for the developement of an implantable artificial heart that can be continuously charged by the transcutaneous energy transmission (TET). I was thrilled to learn that although he was a junior, we shared the same school. Sourabh told me about an interesting encounter during one of the flights. A gentleman sitting next to him was a person who had a heart transplant and was surviving on numerous medications, regular blood tests, and periodic hospitalisation for intracardiac biopsy. A model of the artificial heart was with Sourabh and he offered the gentleman a detailed look and was ready to answer his questions. Satisfied with the inspection, the gentleman replied that he was not confident and had an uneasy feeling about having an inanimate vital appliance within his body even though he was very much aware that such a gadget had the dual ability to cut down the cost and the physical harassment. Monitoring was, of course, necessary, but it did not involve any bodily discomfort. Indeed this was a one-of-incident but this interaction indicates people's attitude about implanted mechanical devices. Since birth human beings have been intrigued by the seat of the mind - and no one wants to hear that the person is "heartless"-- the psyche of a person still believes that the heart has something to do with empathy and similar emotional expressions. To a suffering human patient, the hardship and the problems of a donor transplant are still favoured over a mechanical device.
The quest for an artificial heart began earnestly even before the popularisation of the heart-lung machine and its effective use in various cardiovascular problems, both acquired and congenital. However, progressive dysfunctional myocardium due to any cause leading to inadequate circulation is a different problem. Orthotopic organ transplantation is the only answer. In 1943 William Kolf invented the dialyser in the Netherlands (Groningen) using used orange juice cans, discarded and malfunctioning auto parts, and sausage casings. After two years of further research and the survival of an acute kidney injury patient, the device was ready and earnest Industrial production began. The year was 1945 and Europe was in the throes of the Second World War.; Kolf, by this time had become quite well known as an inventor in the medical field and emigrated to the United States. In the course, he took over the role of the Head of the department of the University of Utah's Unit of Artificial Organs and Division of Biomedical Engineering. The year was 1967, and in the same year, a South African Christian Barnaard created history by successfully transplanting a heart harvested from the body of a fresh accident victim into the chest of a dying subject. Kolf dedicated the rest of his time to developing an implantable artificial heart. Kolf instructed Robert Jarvik, his doctoral student then, to proceed freely with the necessary improvements required for a basic model of an artificial heart. Jarvik made important changes in each successive model. Thus working with Clifford Kwan-Get, a physician-engineer, and Donald Lyman. a biomedical engineer, Jarvik integrated hemispherical diaphragms separating the pneumatic pumps, a simplified drive console, and an inner polyurethane lining minimising the affinity for clot formation.
Though Kolf and his team consistently contributed to developing an implantable artificial heart through research and laboratory work, he was not the first to conceive this idea. History shows that Demikov of Russia, fabricated and used some sort of alternative circulation for the creation of his operative monsters. "The world's first implantable total artificial heart was designed by Vladimir Demikhov as a fourth-year biology student in Voronezh, Soviet Union, in 1937. As a prototype of his device, Demikhov must have used an apparatus for extracorporeal blood circulation invented by Sergei Bryukhonenko of Moscow. The device was the size of a dog's native heart and consisted of two diaphragm pumps brought into motion by an electric motor. A dog with an implanted device lived for 2.5 hours. In addition to having the prototype, the preconditions for Demikhov's artificial heart creation were his manual dexterity, animal physiology expertise, and mechanistic worldview". In 1949 William Sewell and William Glenn made a model of an implantable artificial heart at Yale for dog experiments. The duo claimed around 60 minutes of survival for their model of an artificial heart-implanted dog. Kolf also implanted one of his earlier models in a dog at the same Cleveland Clinic, in1957, which survived for 90 minutes. Kolf moved to University of Utah, Salt Lake City, and then concentrated his research on implantable artificial hearts.
A narrative about the implantable artificial heart will be incomplete if there is no mention of Paul Winchel. This person was a certified ventriloquist and he claimed to have put forward his design of a total artificial heart for the patent. However, thorough historical research proved his claims erroneous.
Domingo Liotta, an Argentine, started an independent implantable total artificial implantable heart at Lyon (France) in 1958. The next year he shifted to the National University of Cordoba in Argentina (1959). In 1961 Liotta presented an interesting paper at the American Society for Artificial Organs where along with his futuristic model, he proposed three other possibilities --
1. an implantable electric motor,
2. an implantable rotating pump with an external electric motor, and
3. a pneumatic pump.
The power drive had to be external, per the technology at the time. Initially, Liotta collaborated with Michael DeBakey, but after a period of apparent disinterest and inactivity, Liotta became frustrated and had a pact with D.A. Cooley to perform a transplant with Liotta's device as a bridge at a different centre and when DeBakey was busy lobbying in Washington. The year 1969 in December Liotta and Cooley did the transplant as planned. Liotta's device supported the circulation satisfactorily for 48 hours after which a donor heart was found and the definitive transplant operation was done. The transplanted patient did not survive long and expired after a severe fungal infection consequent to incomplete immunosuppression. This incident is famous because it strained DeBakey and Cooley's relationship for a long period.
William Devries joined Kolf's artificial implantable heart programme in 1981 at the University of Utah, Salt Lake City, and applied to the FDA for formal permission for the implantation of a Jarvik-7 model, that gave the best animal experiment results In 1982, Dr. Barney Clark, a retired dentist. had end-stage heart failure and consented. Dr. Clark lived for 112 days and was constantly connected to the 480-pound Utah drive console; He never left the hospital and ultimately succumbed to multi-organ failure.
Devries considered the transplant of an artificial pneumatically driven heart a success and though Barney Clark had consented to this experimental procedure, Devries could not handle the intense media glare. He shifted his work to the Humana Hospital Audubon in Louisville, Kentucky, where he did the second Jarvik-7 transplant on Bill Schroeder. Schroeder made history surviving 620 days with the device. During the recovery phase in the hospital, he enjoyed a can of Coor's beer and even had a telephonic conversation with Reagan, who was the President then. The recovery was progressing satisfactorily and fitted with a lighter, compact, and movable drive-console, the patient was made ambulatory. He was officially discharged from the hospital and set up a specially equipped house nearby. Embolic strokes followed by partial recovery, bleeding episodes that, somehow, could be controlled, treatable episodes of infections, etc., all happened while he lived after the operation and ultimately expired from a combination of respiratory failure and sepsis.
The use of Jarvk-7 as destination therapy has been few and sporadic so far. Kolf and Jarvik initially used biopolymers and other compatible plastics for the construction, Periodic changes and improvements were made. The device has been mostly used as a bridge until a donor heart is available. Conservative estimates suggest more than 2000 implants in countries and patients where money is not a problem. initially, Symbion first marketed the prototype of the Jarvik-7 model. (contd.)
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