Cadaveric versus Living Tissue Grafts

There are two current standard sources for organ transplants: cadaveric and living tissue graft donations. From the point of view of the recipient, there are not many significant differences between living and cadaveric transplantations. The individual must still be evaluated in the same manner, and crossmatching with the donor is performed to ensure the immunological feasibility of the procedure. Most intraoperative practices are identical except for the need to obtain greater exposure of the recipient vessels for patients receiving cadaveric grafts. Postoperative care will include immunosuppressant therapy and general monitoring of patient health (such as evaluation of fluid and electrolyte balance).

Demand for organ transplants has increased dramatically since the establishment of transplantation therapy. In fact, there is currently a substantial mismatch between allograft demand and sourcing. This has spurred the creation of an organ waiting list. In 2001, more than 23,000 patients received an organ transplant, 17,000 of which came from deceased donors and 6,500 of which came from living donors. Even though these numbers appear high, it is important to note that less than 25% of individuals are able to receive vital organs from the waiting list. Despite the number of transplants performed in 2001, 6000 patients were reported to have died on the waiting list still in need of a transplant.

The History of Organ Transplantation

P.B. Medawar

The basic techniques necessary for transplantation were understood and developed since the turn of the century. In the early 1900s, a Viennese surgeon attempted the first organ removal and reinsertion in a procedure involving an autologous animal kidney graft. His success led him to investigate further the possibility of transplantation. He failed miserably due to the fact that he crossed the species boundary unknowingly causing immediate and fatal graft rejection. This initial failure had the effect of stunting transplantation progress during the 1920s and 1930s. However, in the 1940s, P.B Medawar recognized that autologous skin grafts were accepted, whereas those given from one relative to another were rejected. This discovery led him to suggest that there was an immunological response. This barrier needed to be overcome for a successful allogeneic graft transplantation. He correctly hypothesized that the human immune system, which is designed to attack foreign bodies, is able to determine that the grafts were non-self, and therefore enact effector mechanisms to ultimately reject the graft. These discoveries induced a new interest in transplantation and instigated successful transplantation attempts. In 1954, Dr. Joseph E. Murray, who received the Nobel Prize for Medicine in 1990, achieved the first successful kidney transplant between identical twins in Boston. In 1967, a South African heart surgeon named Christian Barnard performed the first human heart transplant at Groote Schur Hospital in Cape Town. However, the tendency of the immune system to attack the grafts impeded the success of organ transplantation. In 1978, the immunosuppressive drug Cyclosporine was introduced and the problem of rejection was largely overcome.

Landmarks in Transplantation

1954: Dr. Joseph Murray performed the first successful kidney transplant between living, identical twins in Boston, Massachusetts.
1967: Dr. Thomas Starzl performed the first successful liver transplant in Denver, Colorado.
1968: Dr. Norman Shumway performed the first successful heart transplant in the United States at Stanford University Hospital in California.
1981: Dr. Bruce Reitz performed the first successful heart-lung transplant at Stanford University in California.
1983: Dr. Joel Cooper performed the first successful single lung transplant at the Toronto General Hospital in Toronto, Canada.
1986: Dr. Joel Cooper performed the first successful double lung transplant at the Toronto General Hosptial in Toronto, Canada.
1989: Dr. Christoph Broelsch performed the first successful living-related liver transplant at the University of Chicago in the United States.
1990: Dr. Vaughn Starnes performed the first successful living-related lung transplant at Stanford University Medical Center in California.

Which organs and tissues can be transplanted?

Currently, many organs can be transplanted. This list includes: kidneys, lungs, corneas, livers, pancreases, hearts, heart valves, intestines, bones, tendons, skin, and bone marrow. Of the solid organs, there is the most demand for the kidney, heart and liver. Consequently, these organs are the most commonly transplanted tissues.

How many people benefit from the practices of organ transplantation?

There are currently around 85,000 waiting list candidates in the United States, and 2,000 to 3,000 transplants are performed each month in the United States. About 52,000 people receive whole organ replacements in the world yearly. According to the United Network for Organ Sharing (UNOS), a daily average of 70 people receive either cadaveric or living tissue donations, while an average of 16 patients die every day waiting for an organ, due to limited availability. Current research in fields such as tissue engineering and cloning aims to eliminate the scarcity of available organs.

Immunosuppressive Therapy

Allogeneic transplantation requires immunosuppression for graft survival. Many different forms of treatment have been developed and are discussed in subsequent sections. In general, immunosuppressive therapy has both beneficial and detrimental effects on the transplant recipient. The negative effects of the therapy arise from the nonspecificity of the drugs administered, resulting in increased risk for infection in the recipient. Recently, however, the clinical results of transplantation in humans have improved significantly, due in large part to improved immunosuppressive therapies that are now in place. This is discussed in depth in later pages.

The Economics of Transplantation

The cost of the transplantation procedure and postsurgical care is often a source of great anxiety for the recipient of a graft. Several components relate to the cost of the transplant including hospital costs, physicians' charges, medical supplies, diagnostic tests, postsurgical costs for follow-ups, and medications. The immunosuppressive medications and follow-up care are vital aspects of the transplantation procedure, but the daily drug therapies can add of up to thousands of dollars per year. Transplant recipients and their families often struggle to find the needed coverage, so several supporting transplant organizations have been developed to ensure recipients continue to receive these vital medications.

Significance of Organ Transplantation in the Present

Transplantation has become the treatment of choice for many patients suffering from organ failure or complications arising from diseases of specific organs. This treatment option has been making rapid progress. Several factors have contributed to these improvements. These include increased efficacy of drug therapies used to treat and prevent organ rejection, technical advances in surgery, diagnostic test methods for monitoring patients, improved histocompatibility testing, and enhancement in organ procurement procedures. Earlier and more accurate detection of rejection as well as a more comprehensive understanding of the immune system have also played roles in improving patient and graft survival.

A good indication of the transplantation success over the past several decades is the improvement over time in one-year patient survival rates. A direct result of improved techniques and higher succes rates is an increase in the number of transplants being performed in the United States each year. A major problem, as stated before, is the limited by the availability of organs.

Statistics on Organ Transplantation

The Department of Health and Human Services, in a report entitled "Transplant Center-Specific Graft and Patient Survival Rates," found these statistics:

Percentage of Patients Alive One Year After Transplant:

93.8% - kidney transplants (the most common transplant procedure)
90.5% - pancreas transplant
82.4% - heart transplant
76.7% - liver transplant
68.4% - lung transplant
57% - heart-lung transplant