Organ Transplantation: Pre-transplant Assessment and Post-transplant Management

Overview

Solid organ transplantation is an accepted, successful, and commonly employed treatment option for patients with end-organ failure. Transplant recipients who have received a heart, kidney, liver, pancreas, lung, or small intestine now live longer with an overall improved quality of life. Progress in the development of immunosuppressive therapies and in methods of organ procurement and distribution has also facilitated the transplant process. Even patients with infectious diseases, such as HIV infection, or a history of certain cancers are now potentially eligible for transplant.

In the US, the United Network for Organ Sharing (UNOS), a non-profit organization endowed by Congress but reporting to the Department of Health and Human Services, regulates the allocation and distribution of donor organs. UNOS has two branches: the Organ Procurement and Transplant Network (OPTN) and the Scientific Registry of Transplant Recipients (SRTR). The OPTN divides the country into 11 distinct geographical regions or donation service areas (DSA); each region has its own waiting list. Allocation of organs generally follows a local, regional, and national progression, where local refers to the boundaries of the DSA. The length of time spent on the waiting list can differ greatly among regions.

Determination of priority is organ specific. For kidneys, the length of time on the waiting list is the primary determining factor, although patients listed simultaneously for transplant of a kidney and another solid organ have greater priority. In addition, full human leukocyte antigen (HLA) compatibility (zero antigen mismatch) confers priority. Pediatric recipients (those patients age 18 and under) of kidneys and livers take priority over adults. Within the last few years, OPTN/UNOS Kidney Transplantation Committee has reviewed this allocation procedure and drafted new guidelines taking into account a candidate's ability to survive on the waiting list and creating a measure of kidney quality that would allow for optimizing the match between donors and recipients. The Lung Allocation Score (LAS) is a calculated score for patients over 12 years of age that identifies, among other things, the severity of illness and the likelihood of a successful transplant outcome. The score undergoes frequent modifications based on, among other things, shifts in the characteristics of the candidate cohort, with the consistent goal of reducing time spent on the waiting list. That score, in addition to other factors, includes age, blood type, and geographical location, and determines waiting-list placement for potential lung transplantation recipients. OPTN limits the allocation of lungs to patient's less than 12 years of age to donors within the same age range. This policy has come under scrutiny due to a highly publicized case in which the parents of a 10-year-old girl appealed to a federal judge to allow the patient access to lungs from the adult donor pool. Increasingly, patients with acute respiratory failure have been placed on a mechanical circulatory support (MCS) device, an extracorporeal membrane oxygenator (ECMO), as a bridge to transplant. The Model for End-Stage Liver Disease (MELD) is also a calculated score that predicts how urgently a patient over 12 years of age will need a transplant within the next 3 months. The only exception to the MELD system is a special category known as “Status 1.” Status 1A patients have suffered acute hepatic failure and might die within hours or days without a transplant. Boxes 58-1 and 58-2 list the LAS and MELD criteria. Since 1999, heart transplant recipients, likewise, receive organs based on medical urgency. Guidelines from 2006 dictate local and regional allocation and allow critically ill patients within a 500 nautical mile radius of the donor's hospital to take priority over less sick patients within the local zone.

Several factors limit the success of organ transplantation. First, there is the ever-present potential for allograft rejection. In addition, immunocompromised hosts are vulnerable to bacteria, viruses, and fungi that are not considered pathogenic in the normal population. Finally, the side effects of immunosuppressive medications that are used to manage rejection can be debilitating, disfiguring, or life-threatening, and increase the risk for neoplasm, problems with bone metabolism, a cushingnoid body habitus, nephrotoxicity, posterior-reversible encephalopathic syndrome (PRES), and the development of diabetes mellitus.

Societal mores also impose limitations. The scarcity of cadaveric organs creates a mismatch between the number of patients who need transplantation and the number who can undergo transplantation. Currently, there are 118,725 active waiting-list candidates for a solid organ transplantation, but only 14,105 transplants were done between January and July of 2013. In recent years, transplant centers have attempted to expand the donor pool by harvesting organs from donors after circulatory death (DCD) and expanded criteria donors (ECD) in addition to harvesting organs from persons who have been declared dead by neurological criteria (i.e., brain death). In response to this problem, the Institute of Medicine (IOM) created a committee to study ways in which the supply of transplantable organs can be increased. The committee's report, released in May 2006, recommended the following: vigorous public education about organ donation; provision of more opportunities for registration as an organ donor; easier access to state donor registries; and renewed attention to improvement of organ procurement systems. A more recent effort includes the establishment of the Transplant Growth and Management Collaborative in 2007, and, in 2008, legislation that gave the Department of Health and Human Services a mandate to issue a National Medal honoring organ donors. Some European countries follow the doctrine of “presumed consent” for post-mortem donation, but the US has not embraced this idea. In fact, New York State Assemblyman Richard Brodsky was unable to attract support for his bill that would assume presumed consent for New York residents.

Organ donation by living donors is an increasingly important potential source of transplantable kidneys, livers, and lungs. This is especially true in Japan where there are no defined criteria for determination of brain death and therefore few cadaveric organs are available for harvest. In the US, living donors may be: related to the recipient; unrelated but emotionally connected; or anonymous, altruistic strangers. According to data from OPTN (from 2013) 11,216 transplanted organs came from deceased donors and 2,889 organ transplants (kidney, liver, lung) came from live donors. Parent-to-child liver transplantation (of the left lateral lobe) is an option, as is adult-to-adult transplantation of the right hepatic lobe. Living-lung donation is also an option for carefully selected candidates, but it requires a lower lobe from two different donors for each single potential recipient. The source of the donated organ (i.e., from a deceased donor or living donor)does not affect recipient outcome.

Living organ donation raises several ethical questions: What is true informed consent regarding both short- and long-term risks for the donor? Is the donor's offer (be it from an emotionally connected or unrelated person) truly voluntary? It is difficult to determine what level of risk is acceptable for a healthy, altruistic donor.

Several retrospective studies of the long-term medical and psychological sequelae in living organ donors have been conducted. Short-term risks for live kidney donors include the morbidity secondary to surgery and anesthesia (e.g., bleeding, infection) and salary loss during the weeks of recovery. For kidney donors, long-term health risks include the development of microalbuminuria and the potential for renal failure in the remaining kidney. The mortality rates for kidney donors is 0.05% ; with adult-to-adult liver donation there is a significant degree of morbidity, and mortality rate estimates approach 0.1% for left lateral donation and 0.5% for right lateral donation. To date, no deaths have resulted from living lobar lung donation. One study found that donors lose 15% to 20% of their total lung volume and often experience a decrease in exercise capacity. Another study demonstrated that both the forced vital capacity (FVC) and forced expiratory volume at 1 minute (FEV1) returned to 90% of baseline at 1 year post-lobectomy.

Psychiatric Evaluation of the Transplant Patient

Psychiatrists and other mental health professionals are involved in many different aspects of the transplantation process. In some centers, a designated psychiatrist works with a specific team: for example, the kidney transplant team. Other transplant centers rely on general hospital psychiatric consultation services, psychologists, or social workers to provide case-by-case consultation. The “involvement” of mental health professionals ranges from the pre-operative evaluation of candidates and living donors, to the short- and long-term post-operative management of solid organ recipients.

The psychiatrist or other mental health professional plays an important role in the evaluation of the patient who is approaching a transplant. Initially, the psychiatrist conducts a thorough psychiatric evaluation of the potential recipient to determine suitability for transplant. The psychiatrist must be familiar with medical and surgical problems facing the patient (both before and after transplantation), in order to educate both the patient and the family members about the risks and benefits of transplantation.

The psychiatrist may also act as a liaison between the patient (and family members) and the transplant team. The patient will need support, direction, and clarification of the transplant team's expectations and concerns. The transplant team may require help interpreting a patient's behavior. The psychiatrist can direct the team's attention on ethical dilemmas that may arise, particularly in the area of directed living donation by a related or unrelated donor.

After transplantation, the psychiatrist will be instrumental in guiding the family through the patient's often difficult and unpredictable post-operative course, as well as in managing the neuropsychiatric sequelae secondary to graft rejection, infection, and immunosuppression.