Texas physicians and scientists made numerous contributions to the field of human heart transplantation as it evolved from preliminary experimentation to an accepted orthodox therapy for patients with end-stage cardiac disease. Two Houston surgeons, Michael E. DeBakey and Denton Cooley, have been in the forefront in developing heart surgery and heart transplantation. DeBakey and his team performed the first successful coronary artery bypass graft procedure on November 23, 1964. By the mid-1980s more than one-half million coronary bypass surgeries were performed each year in the United States to extend the lives of patients. Cooley and his associates performed the first heart transplant in the United States on May 3, 1968, at St. Luke's Hospital in Houston. The first transplant patient, Everett Thomas, lived for 204 days with the heart donated from a fifteen-year-old girl. On August 31, 1968, DeBakey and his team performed the first simultaneous multi-organ transplant, removing two kidneys, a lung, and a heart from one donor and implanting them into four different patients. On September 15, 1969, Cooley performed the first heart and lung transplant to the same patient. His two-month-old patient lived only fourteen hours, and died of respiratory insufficiency. Although cardiac transplantation was technically possible in the late 1960s, it had limited therapeutic success. Initially, patients seemed to do well following the transplantation, but within a short period the recipient's body would reject the donor's heart. DeBakey and Cooley reported that sixty of the first 100 heart transplant recipients died by the eighth day following surgery.
The available supply of donor hearts has never met the demand. Research has attempted to fill the gap through the development of artificial hearts. Texas has been the site for pioneering work in the evolution of a total artificial heart and of left ventricular assist devices. In the early 1960s Domingo Liotta began research at DeBakey's Baylor laboratories in Houston to develop an artificial human heart and to work on devices that would provide circulatory and ventricular assistance in acute clinical situations. Liotta also coordinated his efforts with scientists and engineers at Rice University. DeBakey and Liotta reported the first two successful implantations of pneumatically driven left ventricular bypass pumps in humans at the Baylor College of Medicine in 1963 and 1966. In February 1963 DeBakey proposed that the federal government support an organized program to develop a total artificial heart. The Artificial Heart Program was established at the National Institutes of Health in 1964. The mechanical heart was conceived as a temporary "bridge" to provide additional time for patients waiting for a donor heart to become available. In early 1969 Cooley established the Cullen Cardiovascular Laboratories at the Texas Heart Institute in Houston and immediately began work on constructing and testing artificial hearts. On April 4, 1969, he became the first surgeon in the world to implant a total artificial heart in a human. The TAH provided total cardiac support for sixty-four hours until a suitable heart donor could be located. The patient, Haskell Karp, regained consciousness after the transplantation was accomplished but died thirty-two hours later from pneumonia and renal failure. This experience demonstrated that mechanical heart substitutes could afford circulatory support and could be used as a bridge prior to cardiac transplantation. The artificial heart Cooley used to provide Karp with cardiac support is in the Smithsonian Institution in Washington. Implantation of that artificial heart sparked a controversy between the two Houston heart surgeons and their respective institutions concerning who had developed the mechanical heart for clinical use. One of the chief designers, Liotta, had worked in both Cooley's and DeBakey's labs. Extensive investigations and litigations followed and the media coverage was intense. DeBakey and Cooley's personal and professional rivalry continued for decades.
Relatively few transplantations were performed in the 1970s and the surgery was still considered experimental. Some progress during this decade was made when the Texas state legislature joined other states in defining "brain death" as a legal terminal event, which enabled the acquisition of donor hearts to become better organized. The technique for removing organs, preserving them, and transporting them improved. Blood and tissue typing of donors became more standardized. National and international registries were formed to help bring patients awaiting transplants together with organ donors. Mortality results also improved as more experience was gained in preparatory and post-operative care. In the early 1980s the discovery of new anti-rejection medications, chiefly cyclosporine, made long term survival more likely. Unlike other immunosuppressants, cyclosporine did not wipe out the body's immune defenses. Rather, it selectively deactivated that part of the immune system that causes tissue rejections. This event dramatically impacted the field, and human heart transplantation finally became a viable reality. Heart transplant programs in Texas were reinstituted. By 1987 80 percent of patients who received heart transplants survived for at least one year. The five-year survival rate among those heart recipients treated with cyclosporine was 78 percent. Some patients have survived more than ten years with new hearts.
Heart transplantation is no longer an experimental procedure but rather a highly effective therapy for the treatment of end-stage heart disease. According to the United Network for Organ Sharing, a total of 26,704 heart transplantations have been reported worldwide, and 1,804 of these were performed in Texas. It is estimated that as many as 15,000 people per year could benefit from a heart transplant, but the actual number of recipients is constrained by the donor supply. Worldwide, just over 3,000 heart transplants are performed each year. In 1994 167 of these were in Texas.
In September 1994 the rival institutions in Houston announced a change of heart. Methodist Hospital of Houston and St. Luke's signed a letter of intent to merge the two world-renowned heart-transplantation centers. In 1995 O. H. Frazier, the chief of cardiopulmonary transplantation and codirector of the Cullen Cardiovascular Research Laboratories at the Texas Heart Institute, continued work in both heart transplantation and artificial heart research.