Faculty Bibliography

BACKGROUND: Thousands of patients with chronic renal failure die yearly and are unable to have a kidney transplant due to the severe shortage of donors. Therapeutic plasma exchange (TPE) is performed to remove ABO antibodies and permit ABO-incompatible (ABO-I) kidney transplants, but there is only limited research within this area and a lack of standardized protocols for TPE. This article reviews the literature to provide a historical perspective of TPE for ABO-I kidney transplantation and also provides the Johns Hopkins Hospital protocol with a focus on both titers and TPE. STUDY DESIGN AND METHODS: The TPE treatment plan is based on ABO titers with the goal of a titer of 16 or less at the anti-human globulin (AHG) phase before surgery. Pretransplant therapy consists of every-other-day TPE followed immediately by cytomegalovirus hyperimmune globulin. ABO antibody titers are closely monitored before and after transplantation. After transplantation, TPE therapy is performed for all patients to prevent rebound of anti-A and anti-B titers until tolerance or accommodation occurs. TPE is discontinued and reinstituted based on the clinical criteria of creatinine levels, biopsy results, and ABO titer. RESULTS: Fifty-three ABO-I kidney transplants have been completed with no episodes of hyperacute antibody-mediated rejection (AMR) and only three episodes of AMR. One-year death-censored graft survival is 100 percent and patient survival is 97.6 percent. CONCLUSIONS: While randomized clinical trials are needed to evaluate the optimal method and protocol to remove ABO antibodies, the current literature and our results indicate a critical role for TPE in ABO-I renal transplantation.

OBJECTIVE: To quantify the independent association between obesity and access to liver transplantation. BACKGROUND: Obesity is associated with higher complication rates, longer hospitalization, and worse survival after liver transplantation. Nevertheless, transplantation provides survival benefit to patients with end-stage liver disease, regardless of body mass index (BMI). We hypothesized that, despite survival benefit, providers were reluctant to transplant obese patients because of the inherent difficulty of these cases and their inferior outcomes. Our goal was to quantify the independent association between BMI and waiting time for orthotopic liver transplantation as a surrogate marker for this reluctance. METHODS: We studied 29,136 wait-list candidates in the model for end-stage liver disease (MELD) era, categorized as severely obese (BMI 35-40), morbidly obese (BMI 40-60), and reference (BMI 18.5-35). All models were adjusted for factors relevant to the allocation system, factors possibly influencing access to healthcare, and factors biologically related to disease progression and outcomes. RESULTS: The odds of receiving a MELD exception were 30% lower in severely obese and 38% lower in morbidly obese patients. Similarly, the likelihoods of being turned down for an organ were 10% and 16% higher, and the rates of being transplanted were 11% and 29% lower in severely obese and morbidly obese patients, respectively. CONCLUSIONS: Current practice seems to indicate a reluctance to transplant obese patients. If indeed as a community we feel that liver allografts should not be distributed to patients with excessive postoperative risk, we should consider expressing this as a formal change to our allocation policy rather than through informal practice patterns.

Providing transplantation opportunities for patients with incompatible live donors through kidney paired donation (KPD) is seen as one of the important strategies for easing the crisis in organ availability. It has been estimated that an additional 1000-2000 transplants per year could be accomplished if a national KPD program were implemented in the United States. While most of these transplants could be arranged within the participants' local or regional area, patients with hard-to-match blood types or broad HLA sensitization would benefit from matching across larger geographic areas. In this case, either patients or organs would need to travel in order to obtain maximum benefit from a national program. In this study, we describe how a triple KPD enabled a highly sensitized patient (PRA 96%) to receive a well-matched kidney from a live donor on the opposite coast. The kidney was removed in San Francisco and transported to Baltimore where it was reperfused 8 h later. The patient had prompt function and 1 year later has a serum creatinine of 1.1 mg/dl. This case provides a blueprint for solving some of the complexities that are inherent in the implementation of a national KPD program in a large country like the United States.

Although the majority of deceased-donor kidneys are donated after brain death, increased recovery of kidneys donated after cardiac death could reduce the organ shortage and is now a national priority. Racial disparities in donations after brain death have been well described for renal transplantation, but it is unknown whether similar disparities occur in donations after cardiac death. In this study, outcomes of adult deceased-donor renal transplant recipients included in the United Network for Organ Sharing database (1993 through 2006) were analyzed. Among black recipients of kidneys obtained after cardiac death, those who received kidneys from black donors had better long-term graft and patient survival than those who received kidneys from white donors. In addition, compared with standard-criteria kidneys from white donors after brain death, kidneys from black donors after cardiac death conferred a 70% reduction in the risk for graft loss (adjusted hazard ratio 0.30; 95% confidence interval 0.14 to 0.65; P = 0.002) and a 59% reduction in risk for death (adjusted hazard ratio 0.41; 95% confidence interval 0.2 to 0.87; P = 0.02) among black recipients. These findings suggest that kidneys obtained from black donors after cardiac death may afford the best long-term survival for black recipients.