The Total Artificial Heart as a Bridge to Cardiac Transplantation

Christiaan Barnard's ¹ first implantation of a cardiac allograft, in December 1967, led to a flurry of interest in cardiac replacement. However, the few surgeons who thereafter became active in cardiac transplantation soon realized that the shortage of donor organs severely limited the number of procedures they could perform. Moreover, allografts were seldom available in urgent circumstances. Although a few devices were available for temporary left ventricular support, none was sufficient for complete biventricular support.

Much of the initial work in the field of total artificial hearts was done in Willem Kolff's laboratories in Cleveland and later in Salt Lake City. Dr. Kolff and his associates, including Domingo Liotta, Tetsuzo Akutsu, Yukihiko Nosé, C.S. Kwann-Gett, and Robert Jarvik, developed various pulsatile devices, mostly pneumatically activated. In 1961, we recruited Liotta for our laboratory at Baylor, where he continued design and fabrication of his biventricular device, which we thought would be suitable for human implantation. Dr. Liotta had become frustrated because he felt there was little chance that he would be able to implant the device clinically in Salt Lake City. At Baylor, Liotta continued his in vitro and in vivo experiments with pumps of pneumatic design. Soon, single pumps were implanted by Crawford ² in 1 patient for left ventricular assistance and by DeBakey ³ in several patients for temporary support during the immediate postoperative period. One of these patients was successfully weaned from support and survived.

After discussing an appropriate initial indication for the pneumatically activated biventricular device, Dr. Liotta and I began a series of orthotopic implantations of the device in calves. Although the results from calves were not encouraging, we were convinced that such a device could be practical as a bridge to orthotopic transplantation. We hired an engineer to produce a pneumatic drive console, which would enable us to use the device in human beings (Fig. 1). The expandable membrane of the heart was constructed of Dacron embedded in Silastic. A reticular fabric surface was chosen, to mimic the surface used in vascular grafts. Because of their wide orifice and freedom of flow, ⁴ Wada-Cutter hingeless valves were used in the heart (Fig. 2). These valves had a degree of incompetence, a disadvantage that proved later to be an advantage, since the regurgitant stream discouraged thrombus formation.

Fig. 1 The pneumatic drive console.

Fig. 2 Photograph of the Liotta heart. Note the Wada-Cutter hingeless valves.

Implantation of the Total Artificial Heart

The patient who received this device was a 47-year-old man with a history of advanced coronary occlusive disease and a 10-year history of myocardial infarction; he was almost totally disabled. He became a candidate for the total artificial heart after he had been on our service for a month. During that time, we had tried to persuade him to undergo transplantation, which he had refused. He had read about our experience with ventricular resection for postinfarction myocardial aneurysm, and he wanted us to try remodeling his heart first. He did consent to implantation of the mechanical heart, if the attempted remodeling repair failed.

The patient's operation was performed on 4 April 1969, using cardiopulmonary bypass for circulatory support. ⁴ When his heart was emptied of blood, it collapsed like a deflated basketball. The ventricular cavity and papillary muscles had mostly been replaced by scar tissue. The ventricle was plicated in an effort to restore a more normal configuration, but our efforts failed to produce even marginal function. Thus, the moment of decision arrived. The engineer with the device was summoned, and we proceeded to excise the diseased heart and implant the Liotta artificial heart (Fig. 3). Domingo Liotta assisted in the procedure.

Fig. 3 World's 1st implantation of a total artificial heart in a human being, 4 April 1969. Surgeon is Denton A. Cooley.

To our enormous gratification and relief, the patient awakened and, for the next 24 hours, seemed to improve. However, hemolysis and deteriorating renal function left us with transplantation as our only alternative and with an urgent need to procure a donor organ. Immunosuppression was begun, using azathioprine (Imuran), prednisone, and antilymphocyte globulin.

The Transplant Operation

A frantic search for a donor ensued. Finally, we received a call that a donor heart was available in Boston. The blood types of donor and patient matched, enabling us to proceed. A Lear jet was chartered to take 2 attendants from our intensive care unit to Boston to bring the donor back to Houston. On the flight back, the plane's hydraulic system failed, and the pilot was forced to land without brakes at a small airport halfway to Houston. Another jet was sent for the donor and attendants. Finally, they arrived safely in Houston. During the ambulance ride to the hospital, the donor's heart fibrillated, requiring thoracic compression for 5 minutes. On arrival at the hospital, electrical countershock was applied to restore normal rhythm. The donor was taken immediately to the operating room for removal of the heart.

Just 72 hours after the artificial heart had been implanted, the patient was again prepared for surgery. Cardiopulmonary bypass was instituted, and the device was replaced by the allograft. About 36 hours later, the patient died of sepsis secondary to immunosuppression, in combination with kidney failure and allograft rejection. Thus ended an exhausting effort for our entire team.

Results

Although the patient did not survive long after the transplant, much useful information was gleaned from this 1st implantation of an artificial heart. When we examined the device, we did not find any thrombi, and the surfaces were covered by a smooth lining of fibrin and platelets. Most important, we learned that human circulation could be successfully sustained by a mechanical pulsatile device. This experience led us to attempt implanting devices in several other patients, with limited success.

In 1974, Dr. Tetsuzo Akutsu joined our staff to continue development of his artificial heart. In 1981, the Akutsu heart was used as a bridge to transplantation (the 2nd implantation of an artificial heart in the world) in a 36-year-old man who had heart failure after undergoing a coronary artery bypass operation. ⁵ Unfortunately, this patient died after transplant. We also implanted Jarvik-7 total artificial hearts in 2 patients. The Jarvik-7, designed by Robert Jarvik, was the most widely used of any total artificial heart. ⁶ Before the Food and Drug Administration called for a moratorium on the implantation of artificial hearts in the United States, more than 100 orthotopic total hearts were implanted by a number of investigators—either as bridges or as complete heart replacements.

Whether permanent, mechanical, orthotopic replacement of the heart will be feasible or practical remains a moot question. In my opinion, the discomfort of the patient remains a concern. Interest in the development of implantable total artificial hearts continues, however, and, perhaps in the near future, a reliable pump will be available for clinical implantation. Meanwhile, implantable left ventricular assist devices have produced promising results for the field of circulatory support.

Addendum

Since this report was prepared, Dr. Laman A. Gray and his team at Jewish Hospital in Louisville, Kentucky, performed an historic implantation of a total artificial heart on 2 July 2001. The AbioCor device that they implanted has been under development and study by researchers at the Texas Heart Institute, working with ABIOMED engineers, for more than 12 years. The patient in Louisville is recovering 8 weeks after the surgery, and the electrically activated mechanical heart reportedly has supported his circulation well. The discomfort he experiences is much less than that endured by patients with the 1st pneumatically activated total artificial hearts. A new era in orthotopic cardiac replacement may be commencing.