Xenotransplantation--caution, but no moratorium.
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Advisory Committees↗
Biomedical subjects
A B Cosimi
Publications and source records attributed to A B Cosimi.
Depletion of anti-Gal(alpha)1-3Gal antibody in baboons by specific alpha-Gal immunoaffinity columns.
Ongoing studies at our center on facilitating transplantation of discordant xenogeneic organs are focused on tolerance induction. To abrogate hyperacute rejection, we have used adsorption methods to eliminate natural anti-Gal(alpha)1-3Gal (alphaGal) antibodies from the circulation of baboons. We have analyzed data concerning antibody removal in baboons that were 1) immunologically naive, 2) receiving conventional pharmacologic immunosuppressive therapy (IS), and 3) treated with a conditioning regimen for tolerance induction. We compared the efficiency of removing alphaGal antibody 1) by perfusion of whole blood through an alphaGal affinity column (CP; n=5) with 2) perfusion of plasma (separated from cellular components by apheresis) through an alphaGal column (CPA; n=39). Our studies demonstrate that 1) CP and CPA are equally effective in removing anti-alphaGal antibody, 2) CPA is the method of choice if multiple adsorptions are required, 3) CPA in naive animals transiently affects levels of total IgG and IgM, 4) four CPAs repeated at 2-4 day intervals in association with heavy IS reduce the pool of anti-alphaGal antibody and total Ig, and 5) splenectomy and/or IS delay the return of anti-alphaGal antibody.
Animals↗
Demonstration of multilineage chimerism in a nonhuman primate concordant xenograft model.
Prior studies from our laboratory have demonstrated that a nonmyeloablative conditioning regimen can induce transient mixed chimerism and renal allograft tolerance between MHC disparate cynomolgus monkeys. We have also shown that this preparative regimen can be extended to a concordant baboon to cynomolgus xenograft model by adding, to the post transplant protocol, therapy designed to prevent antibody production. Here we examine the use of brequinar (BQR) for this purpose and the efficacy of two new reagents developed to demonstrate the establishment of chimerism in the xenograft recipients. The cynomolgus recipients were conditioned with WBI (300 cGy), TI (700 cGy), ATG, cyclosporine, and brequinar sodium. To detect engraftment of the donor marrow, we prepared a polyclonal cynomolgus anti-baboon antibody (CABA) and a monoclonal antibody (215.1), which distinguish baboon and cynomolgus lymphocytes and granulocytes. We employed flow cytometry analysis to detect multilineage chimerism in the xenograft recipients. Five of the six recipients monitored using our new reagents (CABA and 215.1) developed detectable chimerism and only one of these animals lost its kidney to rejection. However, other complications have not permitted assessment of long-term outcome. The features of the multilineage chimerism included the detection of donor granulocytes (1.8-77.4%) and lymphocytes (2.4-22.2%) for 9 to 37 days. Our new reagents permit the detection of multilineage mixed chimerism, which may be a predictor of xenograft tolerance. We also conclude that brequinar may be effective in preventing antibody formation, but because of its toxicity, it is probably not the drug of choice for extension of the mixed chimerism protocol to concordant xenografts.
Animals↗
Anticardiolipin antibodies and hepatic artery thrombosis after liver transplantation.
BACKGROUND: Hepatic artery thrombosis (HAT) remains a devastating complication after liver transplantation. Various factors have been implicated in the pathogenesis of HAT, such as clotting abnormalities, increased hematocrit, and technical complications, but the role of anticardiolipin antibodies has not been evaluated. We investigated the possible association between HAT and anticardiolipin antibodies in adult patients who underwent liver transplantation. METHODS: Seven patients with HAT after orthotopic liver transplantation, 28 liver recipients without HAT, and 35 normal blood donors were evaluated. Determination of IgM and IgG anticardiolipin antibodies was performed by enzyme-linked immunosorbent assay using pretransplant serum from all allograft recipients. Clinical information was obtained from chart review. Fisher's exact test and Wilcoxon rank sum test were used for statistical analysis, and all P-values were two-tailed. RESULTS: Overall, 22 of 35 (63%) liver recipients had a positive anticardiolipin antibody test (either IgG or IgM titer >4 SD from the normal controls). The test was positive in 7 liver recipients (100%) with HAT compared with 15 out of 28 patients (54%) without HAT (P=0.031). As compared with liver recipients without HAT, patients with HAT also tended to have a higher mean anticardiolipin titer of IgG and IgM and a lower pretransplant platelet count; however, these differences were not significant. CONCLUSIONS: Our findings indicate that anticardiolipin antibodies are frequently elevated in patients with liver failure and may contribute to the pathogenesis of HAT after liver transplantation. Other potential consequences of anticardiolipin antibodies in end-stage liver disease remain to be determined.
Adult↗
Nephrotic syndrome after liver transplantation in a patient with hepatitis C virus-associated glomerulonephritis.
In recent years, hepatitis C virus infection has been reported to be typically associated with membranoproliferative glomerulonephritis and less frequently with membranous nephropathy. Treatment of hepatitis C with interferon-alpha can reduce viremia and improve renal disease. After liver transplantation for hepatitis C virus-associated liver failure, standard immunosuppressive protocols result in a significant increase in hepatitis C viremia. In this report we describe a patient with end-stage liver disease and biopsy-proven hepatitis C-associated glomerulonephritis who underwent liver transplantation. Within 1 month after transplantation, he developed a severe nephrotic syndrome that paralleled a marked increase in viremia. We discuss the possible pathogenic relationship between hepatitis C virus infection and the nephrotic syndrome that followed liver transplantation.
Angiotensin-Converting Enzyme Inhibitors↗
Modifications of the conditioning regimen for achieving mixed chimerism and donor-specific tolerance in cynomolgus monkeys.
BACKGROUND: We demonstrated previously that a nonmyeloablative preparative regimen can induce mixed chimerism and allograft tolerance in cynomolgus monkeys. METHODS: The current studies were designed to clarify the importance and toxicity of various elements of the allotolerance conditioning regimen by: fractionating or reducing the whole-body irradiation (WBI) dosage; adding deoxyspergualine; or deleting donor bone marrow, cyclosporine, irradiation, or splenectomy. RESULTS: Monkeys treated without donor bone marrow, cyclosporine, or irradiation did not develop chimerism or long-term allograft survival. One of three monkeys treated without splenectomy developed chimerism but died of a surgical complication. The other two did not develop chimerism and rejected by day 117. Six of six monkeys treated with 300 cGy of fractionated WBI developed chimerism. Five of these recipients had long-term graft survival. Only two of four monkeys treated with 250 cGy developed chimerism, so a 2-week course of deoxyspergualine was added. This led to chimerism in two monkeys, but one died of ureteral stenosis and the other died of allograft rejection. An unanticipated high incidence of ureteral complications felt to be secondary to rejection episodes and ischemic injury was observed in the long-term surviving animals. CONCLUSIONS: All parameters of the original preparative regimen seem to be essential for consistent success. The degree of lymphocyte depletion was proportional to the WBI dose. Long-term graft survival was observed only in recipients achieving lymphocyte chimerism of > 1.5%. In this model, lymphocyte depletion seems to be the best predictor of chimerism, and significant lymphocyte chimerism seems to be important in achieving tolerance.
Animals↗
Efficacy of tacrolimus as rescue therapy for chronic rejection in orthotopic liver transplantation: a report of the U.S. Multicenter Liver Study Group.
BACKGROUND: A study was performed by 17 different U.S. liver transplantation centers to determine the safety and efficacy of conversion from cyclosporine to tacrolimus for chronic allograft rejection. METHODS: Ninety-one patients were converted to tacrolimus a mean of 319 days after liver transplantation. The indication for conversion was ongoing chronic rejection confirmed by biochemical and histologic criteria. Patients were followed for a mean of 251 days until the end of the study. RESULTS: Sixty-four patients (70.3%) were alive with their initial hepatic allograft at the conclusion of the study period and were defined as the responder group. Twenty-seven patients (29.7%) failed to respond to treatment, and 20 of them required a second liver graft. The actuarial graft survival for the total patient group was 69.9% and 48.5% at 1 and 2 years, respectively. The actuarial patient survival at 1 and 2 years was 84.4% and 81.2%, respectively. Two significant positive prognostic factors were identified. Patients with a total bilirubin of < or = 10 mg/dl at the time of conversion had a significantly better graft and patient survival than patients converted with a total bilirubin > 10 mg/dl (P=0.00002 and P=0.00125, respectively). The time between liver transplantation and conversion also affected graft and patient survival. Patients converted to tacrolimus < or = 90 days after transplantation had a 1-year actuarial graft and patient survival of 51.9% and 65.9%, respectively, compared with 73.2% and 87.7% for those converted > 90 days after transplantation. The mean total bilirubin level for the responder group was 7.1 mg/dl at the time of conversion and decreased significantly to a mean of 3.4 mg/dl at the end of the study (P=0.0018). Thirteen patients (14.3%) died during the study. Sepsis was the major contributing cause of death in most of these patients. CONCLUSIONS: Our results suggest that conversion to tacrolimus for chronic rejection after orthotopic liver transplantation represents an effective therapeutic option. Conversion to tacrolimus before development of elevated total bilirubin levels showed a significant impact on long-term outcome.
Adolescent↗
Ultra-late recurrence (15 years or longer) of cutaneous melanoma.
BACKGROUND: Melanoma can remain clinically quiescent for decades before regional or distant recurrence appears. This protracted disease free interval challenges the concept of a "cure" for melanoma. METHODS: To understand this prolonged dormancy better, the authors retrospectively studied patients who developed recurrent melanoma 15 years or longer after their initial diagnosis ("ultra-late" recurrence). These cases were identified from 2766 melanoma diagnoses available in the Cancer Registry at the Massachusetts General Hospital (MGH). Histologic features of the primary lesion were also included when possible. RESULTS: Twenty cases were retrieved from the MGH database. There were equal numbers of women and men, although women were younger at the time of initial diagnosis (mean age of women: 29.8 years vs. 43.0 years for men). No patients had more than one primary cutaneous melanoma. The trunk was the most common primary site (35%), although there was no predominant anatomic localization. The average disease free interval was 17.3 years for women, 20.0 years for men, 18.1 years for patients with regional recurrence, and 19.0 years for patients with distant metastases. Distant recurrence was the most common type of recurrence (50% of women and 60% of men). The estimated probability of survival (5 years after recurrence) was 0.8 for regional disease and 0.2 for distant disease. With the available histologic records, it appears that almost all tumors were Clark Level III or IV with thicknesses ranging from 0.8-2.3 mm. In contrast to the published cases, this study did not find that women with lower extremity melanomas were at higher risk for developing ultra-late recurrence. CONCLUSIONS: Ultra-late recurrence of melanoma, although uncommon, can occur in any patient without identifiable risk factors. Because many prognostically favorable melanomas (thin melanomas on extremities) can recur after prolonged disease free intervals, the possibility of delayed recurrence remains and must be kept in mind.
Adolescent↗
Accelerated acute rejection of an apparent A2 renal allograft in an O recipient: report of a case with flow cytometric analysis.
We report a case of accelerated acute rejection of a renal allograft from a presumed ABO histo-blood group A2 donor in an O recipient, in which all of the published criteria for compatibility had been met. Flow cytometric analysis of the A and H antigen expression on the kidney donor's erythrocytes suggested that this donor did not have an A2 phenotype, but rather another subgroup of A. Some of the reported cases of accelerated acute rejection of A2 renal allografts in O recipients may have resulted from misapplication of the results of standard lectin agglutination to the transplant setting. The current case suggests that a more sophisticated method of ABO phenotyping, such as erythrocyte flow cytometric analysis, may be necessary in the transplant setting.
ABO Blood-Group System↗
Biological effects and fate of a soluble, dimeric, 80-kDa tumor necrosis factor receptor in renal transplant recipients who receive OKT3 therapy.
A preliminary clinical study of renal allograft recipients revealed that a dimeric form of the human 80 kDa soluble receptor (sTNFR:Fc) for tumor necrosis factor (TNF) is well tolerated and attenuates the OKT3-induced acute clinical syndrome. The current study determined the in vivo biological effects and fate of sTNFR:Fc in these patients. Serial assessment of both antigenic and biological activities of circulating TNF and sTNFR:Fc have led to the following observations. (1) Although control patients typically responded to the first OKT3 injection with a rapid increase of biologically active TNFalpha, patients on sTNFR:Fc therapy had markedly higher serum TNFalpha antigenic levels, but no detectable bioactivity. Thus, sTNFR:Fc functioned as a potent antagonist, despite its cytokine-carrier effect. (2) Peak sTNFR:Fc levels averaging 800 and 2500 ng/ml were routinely achieved in vivo, using the low-dose (0.05 mg/kg) and high-dose (0.15 mg/kg) protocols. (3) The half-life of circulating sTNFR:Fc was estimated to be approximately 4.4 days, and levels of p80 receptors in treated patients remained significantly above those in control patients for at least 20 days. (4) In vitro blocking studies demonstrated that circulating sTNFR:Fc remained biologically active for 2 weeks. These results demonstrate that under current protocols, significant serum levels of sTNFR:Fc, capable of effectively neutralizing TNF activity over prolonged periods, can be achieved. The persistent OKT3 side effects observed, despite sTNFR:Fc therapy, are therefore likely to be caused by factors other than TNF.
Dimerization↗
Pig to monkey bone marrow and kidney xenotransplantation.
BACKGROUND: The intensity of discordant xenograft cellular rejection makes it unlikely that safe doses of immunosuppressive drugs will alone be sufficient to permit long-term survival. We have therefore concentrated our efforts on establishing tolerance to xenogeneic organs through lymphohematopoietic chimerism and the elimination of preformed natural antibodies (nAbs). METHODS: Here we report the most recent series of 11 technically successful porcine to nonhuman primate transplantation procedures. In eight experimental animals induction therapy consisted of (1) 3 x 100 cGy nonlethal whole body irradiation (day -6 and day -5) to all animals, (2) horse anti-human thymocyte globulin (day -2, day -1, and day 0) to seven of the animals, (3) 700 cGy thymic irradiation (day -1) to five of the animals, and (4) pig bone marrow infused on day 0 (2-9 x 10(8)/cells/kg). On day 0, just before the renal xenograft, the recipient was splenectomized, and antipig nAbs were removed by means of perfusion of the monkey's blood through either a pig liver (n = 6) or a Gal-alpha (1,3)-Gal adsorption column (n = 5). There control animals did not receive this pretransplantation induction therapy but did undergo hemoperfusion and posttransplantation immunosuppression identical to the experimental animals. All 11 recipients were treated after transplantation with cyclosporin A and 15-deoxyspergualin. Recombinant pig-specific growth factors (interleukin-3 and stem cell factor) were given to six experimental animals from day 0 until the termination of the experiment. RESULTS: Analysis of recipients' sera by means of flow cytometry indicated the effective removal of immunoglobulin M and immunoglobulin G nAbs by either liver perfusion or column adsorption. In the eight experimental animals, nAb titers remained low until death (up to 15 days), but in the three control animals nAb titers increased substantially with time. The longest surviving recipient maintained excellent kidney function with creatinine levels at 0.8 to 1.3 mg/dl throughout its course. Death occurred at day 15 from complications caused by a urinary leak and pancytopenia. Histologic examination of the xenograft revealed only focal tubular necrosis and cytoplasmic vacuolization, with trace amounts of fibrin and C3 in peritubular capillaries. In this animal a fraction of the peripheral blood cells (3%) at day 7 were of pig origin as detected by pig-specific monoclonal antibodies. In addition, colony-forming assays performed on a bone marrow biopsy specimen taken at day 14 indicated that approximately 30% of the relatively few myeloid progenitors detected were of swine origin. CONCLUSIONS: We have demonstrated that our protocol is effective in the prevention of hyperacute rejection and in the maintenance of excellent function of the renal xenograft for up to 15 days. These results also indicate that at least short-term engraftment of the xenogeneic donor bone marrow cells is possible to achieve in this discordant large animal combination. Longer survivals will be required to assess the possible effect of this engraftment on induction of tolerance.
Animals↗
Surgical management of primary cutaneous melanomas of the hands and feet.
OBJECTIVE: The purpose of the study was to investigate the surgical management of cutaneous melanomas of the hands and feet. SUMMARY BACKGROUND DATA: Prior studies suggest that patients with melanomes > 1-mm thick should be treated with excision with a 2-cm margin and undergo elective lymphadenectomy in selected circumstances. These recommendations are based primarily on data from melanomas of the trunk and extremities. Melanomas of the hands and feet are less common and less well studied. They pose a surgical challenge because primary wound closure often is difficult, and the incidence and management of regional node metastases are unclear. METHODS: Charts of patients with melanomas of the hands or feet treated at the Massachusetts General Hospital between 1980 and 1994 were reviewed retrospectively. Local recurrence rates and the incidence of regional node metastases were analyzed as a function of histology, margin of excision, and microscopic thickness of the melanoma. RESULTS: Data from 116 patients (39 men, 77 women) with melanomas of the hands (n = 26) and feet (n = 90) were evaluated. Pathologic diagnoses were: acral lentiginous melanoma (48 patients); subungual melanoma (13 patients), and skin of dorsum of the hand or foot (n = 55). Digital amputation was required in all 13 patients with subungual melanoma to maintain local control; still, nodal metastases developed in 46% of patients within 1 year. Seventy-one percent of patients with acral lentiginous melanoma presented with lesions > or = 1.5 mm, and nodes or systemic disease or both developed in 56% of patients. Acral lentiginous melanoma lesions < 1.5-mm thick were treated principally by excision with a 1-cm margin; a local recurrence or metastases did not develop in any of the patients. None of the patients with melanomas on the dorsum of the hand or foot < 1.5-mm thick had a local recurrence, but regional or systemic disease developed in > 50%. Local control in patients with lesions > 1.5-mm thick frequently required skin grafting or amputation. The majority of patients with melanomas > or = 1.5 mm in thickness undergoing elective lymph node dissection had histologically positive nodes for melanoma. CONCLUSIONS: Melanomas of the hands and feet < 1.5-mm thick have a low incidence of nodal metastases and are treated effectively with wide excision of the primary with a 1-cm margin. Thicker melanomas are associated with a > 50% rate of regional or systemic failure. In the absence of metastatic disease, these individuals should undergo local excision with a 2-cm margin and intraoperative lymphatic mapping followed by lymphadenectomy if the sentinel node is positive.
Adolescent↗
Evaluation of recombinant human soluble dimeric tumor necrosis factor receptor for prevention of OKT3-associated acute clinical syndrome.
Tumor necrosis factor alpha (TNFa) has been shown to be the primary cytokine responsible for the OKT3-induced acute clinical syndrome (OKT3-ACS). Recombinant human soluble tumor necrosis factor receptor (TNFR:Fc) is a dimer of the p80 TNF receptor, which binds both TNFa and lymphotoxin (LT). Renal allograft recipients undergoing OKT3 therapy for steroid-resistant rejection were randomized to receive OKT3 alone or in combination with TNFR:Fc to determine its safety and efficacy in decreasing the severity of OKT3-ACS and in restoring renal function. Six of 12 patients were given TNFR:Fc prior to each of the first two injections of OKT3. All patients were monitored for manifestations of OKT3-ACS and changes in renal function. In addition, serial serum samples were assayed for TNFa and TNFR:Fc levels (ELISA) and TNFa bioactivity (L929). No adverse side effects were identified in patients receiving TNFR:Fc. Patients treated with TNFR:Fc had significantly fewer symptoms by day 2 of OKT3, and had a lower overall incidence of chills and arthralgias. Renal dysfunction reversed within 24 hr in the TNFR:Fc-treated group in contrast to the 48-72-hr delay in the control group. Antigenic TNFa levels increased in the control group from < 10 pg/ml pre OKT3 to a mean peak level of 30 +/- 13 pg/ml on day 1 and decreased to pretreatment levels by day 2. TNFR:Fc-treated patients had a mean peak TNFa level of 235 +/- 135 pg/ml, suggesting a carrier effect of TNFR:Fc. In contrast, bioactivity was barely detectable (mean 20 +/- 14 pg/ml) in the day 1 samples from TNFR:Fc-treated patients, whereas significant bioactivity (peak mean 60 +/- 35 pg/ml) was detected in sera from control patients. TNF receptor levels reached 600 ng/ml in treated patients and remained elevated for up to 18 days confirming the long half-life of TNFR:Fc. This phase 1 trial demonstrates that TNFR:Fc is well tolerated and may limit the severity of OKT3-ACS. The most significant observation was a more rapid improvement in renal function in the TNFR:Fc-treated patients. The absence of TNFa bioactivity indicates that TNFR:Fc functions as a TNF antagonist. Further evaluation of higher doses of TNFR:Fc in OKT3-treated patients is currently in progress.
Acute Disease↗
A regional experience with emergency liver transplantation.
Liver transplantation for patients requiring life-support results in the lowest survival and highest costs. A ten year (1983-1993) regional experience with liver transplantation for critically ill patients was undertaken to ascertain the fate of several subgroups of patients. Of the 828 liver transplants performed at six transplant centers within the region over this period, 168 (20%) were done in patients who met today's criteria for a United Network of Organ Sharing (UNOS) status 1 (emergency) liver transplant candidate. Recipients were classified according to chronicity of disease and transplant number (primary-acute, primary-chronic, reTx-acute, reTx-chronic). Overall one-year survival was 50% for all status 1 recipients. The primary-acute subgroup (n = 63) experienced a 57% one-year survival compared with 50% for the primary-chronic (n = 51) subgroup (P = 0.07). Of the reTx-acute recipients (n = 43), 44% were alive at one year in comparison with 20% for the reTx-chronic (n = 11) group (P = 0.18). There was no significant difference in survival for the following: transplant center, blood group compatibility with donors, age, preservation solution, or graft size. For patients retransplanted for acute reasons (primary graft nonfunction (PGNF) or hepatic artery thrombosis [HAT]), survival was significantly better if a second donor was found within 3 days of relisting (52% vs. 20%; P = 0.012). Over the study period progressively fewer donor organs came from outside the region. No strong survival-based argument can be made for separating, in allocation priority, acute and chronic disease patients facing the first transplant as a status 1 recipient. Clearly patients suffering from PGNF or HAT do far better if retransplanted within 3 days. Establishing an even higher status for recipients with PGNF, perhaps drawing from a supraregional donor pool, would allow surgeons to accept more marginal donors, thus potentially expanding the pool, without significantly compromising patient survival. Retransplantation of the recipient with a chronically failing graft who deteriorates to the point of needing life-support is nearly futile, and in today's health care climate, not an optimal use of scarce donor livers.
Acute Disease↗
Hepatitis C viral infection in liver transplantation.
OBJECTIVE: To study the outcomes of patients who underwent liver transplantation for the primary diagnosis of chronic active hepatitis secondary to hepatitis C virus (HCV). DESIGN AND SETTING: Retrospective review within a university medical center. PATIENTS: Seventy-four adult recipients who received 78 orthotopic liver allografts for the primary diagnosis of chronic active hepatitis secondary to HCV between January 1990 and December 1994. Sixty-seven patients (91%) survived more than 2 months and were analyzed further for recurrent HCV infection. MAIN OUTCOME MEASURE: Recurrence of HCV infection, hepatitis, or cirrhosis and survival rates for patients who were undergoing orthotopic liver transplantation for chronic active hepatitis secondary to HCV. RESULTS: Actuarial survival rates for the entire group were 79.3%, 70.9%, and 64.5% at 1,2, and 3 years, respectively. Four patients (5% underwent retransplantation with an actuarial survival rate of 14.3% at 1 year (P<.05). Thirty-eight patients (57%) had evidence of posttransplant HCV infection, 31 patients (46%) showed histologic evidence of viral hepatitis, and 11 patients (16%) experienced portal fibrosis or cirrhosis. Seven (33%) of the deaths and all retransplantations were secondary to recurrent HCV infection. There were no significant differences in age, sex, United Network of Organ Sharing status, associated diagnoses, intraoperative packed red blood cell requirements, OKT3 use, or 1-, 2-, and 3-year survival rates in the recurrent vs nonrecurrent HCV infection groups. A higher incidence of posttransplant cirrhosis was observed in patients who were treated with tacrolimus (FK 506) (31.8% vs 8.9%, P<.05). Twenty-one patients (70%) received interferon alfa antiviral therapy with a significant benefit in the liver function test results during therapy (P<.01). CONCLUSIONS: Despite recurrence of HCV infection in most patients after transplantation, survival following primary orthotopic liver transplantation for chronic active hepatitis secondary to HCV infection remains favorable, and these patients should continue to be candidates for liver transplantation. In contrast, survival following retransplantation for HCV infection is poor and should be reconsidered. There is an apparent association between the intensity of immunosuppression and recurrent HCV infection and cirrhosis that warrants continued evaluation. Interferon therapy appears to afford benefit to patients in whom recurrent HCV hepatitis develops after transplantation.
Actuarial Analysis↗
Ethical dichotomies in organ transplantation. A time for bridge building.
Rapid advances of the past 15 years have resolved many of the technical and immunologic limitations to organ transplantation. With the success rates that can now be achieved, there is increased attention to the limited supply of donor organs and to cost considerations, the remaining obstacles to wide application of organ transplantation. Competition for organs and for funding demands greater focus on patient selection and resource allocation. As Charles Taylor, philosopher and political scientist, has written, ethical formulations inevitably conflict when each is taken to its logical end point. In the 1960s, a life boat ethics framework predominated for selection of transplant recipients. The opposing egalitarian framework of recent decades has allowed for enrollment of older transplant recipients and those with histories of substance abuse. In the United States, alcoholic liver disease has been the most common indication for orthotopic liver transplantation since 1987. Among those awaiting transplantation, urgency has been a priority over time waiting. But many potential transplant candidates who are young and who appear relatively stable die while waiting. Despite the shortage of cadaveric organs, physicians and ethicists have for the most part eschewed rewards or reimbursement for living related organ donation. Such conventions are a function of the prevailing zeitgeist and are susceptible to a paradigm shift in parallel with overall changes in societal regulation of medical practice. Theorists and practitioners are immersed in the trends of the day and the approach at each moment seems preferable to that of the moment preceding. From a practical standpoint it may be possible to bridge disparate ethical constructs. For example, in the wait for solid organ transplantation, a bicameral approach could alternatively accommodate time waiting and urgency. Selection of older patients and those with a past substance abuse history could be limited to those with the best prognosis for compliance and posttransplantation quality of life. Living organ donors and families of nonliving donors could receive incentives of a noncoercive nature that would stimulate participation without sacrificing altruism. Creative approaches are needed to improve fairness and efficacy in solid organ transplantation.
Age Factors↗
A mixed chimerism approach to renal transplantation between concordant nonhuman primate species.
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Animals↗
Selective use of veno-venous bypass in orthotopic liver transplantation.
The use of veno-venous bypass (VVB) during the anhepatic phase of orthotopic liver transplantation (OLT) remains controversial. We employ VVB on a selective basis: patients who tolerate intra-operative supra-hepatic IVC test cross-clamping undergo OLT without VVB while patients who, despite maximal volume resuscitation, develop hemodynamic instability during test cross-clamping, undergo OLT with VVB. The records of 150 adult orthotopic liver allograft recipients transplanted at the Massachusetts General Hospital from January 1984 to December 1994 were reviewed to identify any potential adverse affects on peri-operative, 6 months, 1 year outcomes in recipients foregoing VVB during liver transplantation. Thirty-eight patients (25%) underwent OLT without VVB with actuarial survivals of 78.4% and 69% at 6 months and 1 year. 112 patients (75%) underwent OLT with VVB with actuarial survivals at 6 months and 1 year of 73% and 72%. Demographic data, UNOS status, and diagnoses were similar in each group. There were no significant differences in intra-operative PRBC requirements; lengths of hospital stay; retransplantation rates; or 30 day, 6 months and 1 year survivals between these two groups. There was no significant difference in renal function as determined by preoperative, peak post-operative, discharge serum creatinine levels, or number of patients requiring HD between these two groups. There were two major complications (1.8%) possibly resulting from VVB. In conclusion, patients who tolerate IVC test cross-clamping can safely undergo orthotopic liver transplantation without veno-venous bypass. In our experience, there were no significant differences in peri-operative parameters, post-operative renal function, or short-term survival when compared to patients who, due to hemodynamic instability during IVC cross-clamping, underwent OLT with VVB. Given the potential complications associated with VVB, we feel that in those patients who tolerate intra-operative IVC cross-clamping, it is better to proceed without the use of VVB.
Actuarial Analysis↗