Solid-organ Transplants From Living Donors: Cumulative United States Experience on 140,156 Living Donor Transplants Over 28 Years

BACKGROUND

Transplantation of organs from living donors helps to decrease the organ shortage and shortens waiting times. Living donor (LD) transplantation is also generally associated with better outcomes. Unfortunately, there has been no comprehensive analysis and comparison of all types of solid-organ transplantation from living donors since the inception of the United Network for Organ Sharing (UNOS).

METHODS

Using the UNOS/Organ Procurement and Transplantation Network (OPTN) database, all LD transplants from October 1, 1987, to December 31, 2015, were studied with univariate and multivariate analyses.

RESULTS

A total of 140,090 organs were transplanted from LDs, accounting for 21% of all transplants in the United States. Over 95% were kidney; 4% were liver; and <1% intestine, lung, and pancreas LDs. Only LD kidney transplant patient and graft survival rates were significantly higher compared deceased donor transplants over the period of analysis. The best long-term LD transplant results were achieved in pediatric liver recipients. Significantly more women than men donated organs and significantly more men than women received solid-organ transplants. A regional disparity was observed for LD kidney as well as for LD liver transplants. Despite improvements in outcomes and increased use of nonbiologic donors, the number of LD transplants in the United States has declined. This decline was greater in children than adults and was noted for all types of organ transplants.

CONCLUSION

Further efforts are needed to educate the public, health professionals, and transplant candidates on the advantages of living vs deceased donor organ transplantation. Compared with other countries, LD transplantation has yet to reach its full potential in the United States.

Pancreas Transplantation: An Alarming Crisis in Confidence

In the past decade, the annual number of pancreas transplantations performed in the United States has steadily declined. From 2004 to 2011, the overall number of simultaneous pancreas-kidney (SPK) transplantations in the United States declined by 10%, whereas the decreases in pancreas after kidney (PAK) and pancreas transplant alone (PTA) procedures were 55% and 34%, respectively. Paradoxically, this has occurred in the setting of improvements in graft and patient survival outcomes and transplanting higher-risk patients. Only 11 centers in the United States currently perform ≥20 pancreas transplantations per year, and most centers perform <5 pancreas transplantations annually; many do not perform PAKs or PTAs. This national trend in decreasing numbers of pancreas transplantations is related to a number of factors including lack of a primary referral source, improvements in diabetes care and management, changing donor and recipient considerations, inadequate training opportunities, and increasing risk aversion because of regulatory scrutiny. A national initiative is needed to "reinvigorate" SPK and PAK procedures as preferred transplantation options for appropriately selected uremic patients taking insulin regardless of C-peptide levels or "type" of diabetes. Moreover, many patients may benefit from PTAs because all categories of pancreas transplantation are not only life enhancing but also life extending procedures.

Pancreas After Islet Transplantation: A First Report of the International Pancreas Transplant Registry

Pancreas after islet (PAI) transplantation is a treatment option for patients seeking insulin independence through a whole-organ transplant after a failed cellular transplant. This report from the International Pancreas Transplant Registry (IPTR) and the United Network for Organ Sharing (UNOS) studied PAI transplant outcomes over a 10-year time period. Forty recipients of a failed alloislet transplant subsequently underwent pancreas transplant alone (50%), pancreas after previous kidney transplant (22.5%), or simultaneous pancreas and kidney (SPK) transplant (27.5%). Graft and patient survival rates were not statistically significantly different compared with matched primary pancreas transplants. Regardless of the recipient category, overall 1- and 5-year PAI patient survival rates for all 40 cases were 97% and 83%, respectively; graft survival rates were 84% and 65%, respectively. A failed previous islet transplant had no negative impact on kidney graft survival in the SPK category: It was the same as for primary SPK transplants. According to this IPTR/UNOS analysis, a PAI transplant is a safe procedure with low recipient mortality, high graft-function rates in both the short and long term and excellent kidney graft outcomes. Patients with a failed islet transplant should know about this alternative in their quest for insulin independence through transplantation.

Islet preparation purity is overestimated, and less pure fractions have lower post-culture viability before clinical allotransplantation

BACKGROUND

Replacement of β-cells with the use of isolated islet allotransplantation (IT) is an emerging therapy for type 1 diabetics with hypoglycemia unawareness. The current standard protocol calls for a 36-72-hour culture period before IT. We examined 13 clinical islet preparations with ≥2 purity fractions to determine the effect of culture on viability.

METHODS

After standard islet isolation and purification, pure islet fractions were placed at 37°C with 5% CO2 for 12-24 hours and subsequently moved to 22°C, whereas less pure fractions were cultured at 22°C for the entire duration. Culture density was targeted at a range of 100-200 islet equivalents (IEQ)/cm(2) adjusted for purity. Islets were assessed for purity (dithizone staining), quantity (pellet volume and DNA), and viability (oxygen consumption rate normalized to DNA content [OCR/DNA] and membrane integrity).

RESULTS

Results indicated that purity was overestimated, especially in less pure fractions. This was evidenced by significantly larger observed pellet sizes than expected and tissue amount as quantified with the use of a dsDNA assay when available. Less pure fractions showed significantly lower OCR/DNA and membrane integrity compared with pure. The difference in viability between the 2 purity fractions may be due to a variety of reasons, including hypoxia, nutrient deficiency, toxic metabolite accumulation, and/or proteolytic enzymes released by acinar tissue impurities that are not neutralized by human serum albumin in the culture media.

CONCLUSIONS

Current clinical islet culture protocols should be examined further, especially for less pure fractions, to ensure the maintenance of viability before transplantation. Even though relatively small, the difference in viability is important because the amount of dead or dying tissue introduced into recipients may be dramatically increased, especially with less pure preparations.

Metabolic profile of pancreatic acinar and islet tissue in culture

BACKGROUND

The amount and condition of exocrine impurities may affect the quality of islet preparations, especially during culture. In this study, the objective was to determine the oxygen demand and viability of islet and acinar tissue post-isolation and whether they change disproportionately while in culture.

METHOD

We compared the oxygen consumption rate (OCR) normalized to DNA (OCR/DNA, a measure of fractional viability in units of nmol/min/mg DNA), and the percent change in OCR and DNA recoveries between adult porcine islet and acinar tissue from the same preparation (paired) over 6-9 days of standard culture. Paired comparisons were done to quantify differences in OCR/DNA between islet and acinar tissue from the same preparation, at specified time points during culture.

RESULTS

The mean (±SE) OCR/DNA was 74.0 ± 11.7 units higher for acinar (vs islet) tissue on the day of isolation (n = 16, P < .0001), but 25.7 ± 9.4 units lower after 1 day (n = 8, P = .03), 56.6 ± 11.5 units lower after 2 days (n = 12, P = .0004), and 65.9 ± 28.7 units lower after 8 days (n = 4, P = .2) in culture. DNA and OCR recoveries decreased at different rates for acinar versus islet tissue over 6-9 days in culture (n = 6). DNA recovery decreased to 24 ± 7% for acinar and 75 ± 8% for islets (P = .002). Similarly, OCR recovery decreased to 16 ± 3% for acinar and remained virtually constant for islets (P = .005).

CONCLUSION

Differences in the metabolic profile of acinar and islet tissue should be considered when culturing impure islet preparations. OCR-based measurements may help optimize pre-islet transplantation culture protocols.

Results of open and robot-assisted pancreatectomies with autologous islet transplantations: treating chronic pancreatitis and preventing surgically induced diabetes

For patients with chronic pancreatitis (CP), standard surgical procedures (eg, partial or total resections, drainage procedures) are inadequate treatment options, because they do not confer pain relief and they leave patients prone to brittle diabetes and hypoglycemia. The combination of total pancreatectomy and islet autotransplantation (TP-IAT), however, can create insulin-independent and pain-free states. At our center, from August 2009 through August 2013, 61 patients with CP underwent either open or robot-assisted TP-IAT. The 30-day mortality rate was 0%. The transplanted islet equivalents per body weight ranged from 10,000 to 17,770. In all, 19% of the patients became insulin independent (after a range of 1-24 months); 27% of patients required <10 units of insulin. Moreover, at 12 months after surgery, 71% of the patients were pain free and no longer required analgesics. Our metabolic outcomes could have been even better if most patients had been referred at an earlier disease stage; instead, ∼80% had already undergone surgical procedures, and 91% had abnormal results on preoperative continuous glucose monitoring tests. Only if patients with CP are referred early for a TP-IAT-rather than being subjected to additional inadequate endoscopic and surgical procedures-can insulin-independent and pain-free states be accomplished in most.

Declining numbers of pancreas transplantations but significant improvements in outcome

In the United States, over the past 8 years, the number of pancreas transplantations has steadily declined. This decline comes as a surprise, because patient and graft outcomes have substantially improved during the same period of time. Patient survival rates at 1 year in all 3 recipient categories are >96%; graft survival rates are 82%-89%. Changes in immunosuppressive therapy have had a positive impact on outcome, as have better pancreas donor and recipient selection criteria and refined post-transplantation patient care. Although different factors may have contributed to the declining pancreas transplantation numbers, a more effective process of publicly promoting and widely communicating the improved results of pancreas transplantation is warranted.

Three types of simultaneous pancreas and kidney transplantation

PURPOSE

The purposes of this study were to study and compare clinical and functional outcomes after simultaneous deceased donor pancreas and kidney transplantation (SPK DD), simultaneous deceased donor pancreas and living donor kidney transplantation (SPK DL), and simultaneous living donor pancreas and kidney transplantation (SPK LL).

METHODS

From January 1, 1996 to September 1, 2005, 8918 primary, simultaneous pancreas and kidney transplantation (SPK) procedures were reported to the International Pancreas Transplant Registry. Of these, 8764 (98.3%) were SPK DD, 115 (1.3%) were SPK DL, and 39 (0.4%) were SPK LL. We compared these 3 groups with regard to several endpoints including patient and pancreas and kidney graft survival rates.

RESULTS

The 1-year and 3-year patient survival rates for SPK DD were 95% and 90%, 97% and 95% for SPK DL, and 100% and 100% for SPK LL recipients, respectively (P ≥ .07). The 1-year and 3-year pancreas graft survival rates for SPK DD were 84% and 77%, 83% and 71% for SPK DL, and 90% and 84% for SPK LL recipients, respectively (P ≥ .16). The 1-year and 3-year kidney graft survival rates for SPK DD were 92% and 84%, 94% and 86% for SPK DL, and 100% and 89% for SPK LL recipients, respectively (P ≥ .37).

CONCLUSIONS

Patient survival rates and graft survival rates for pancreas and kidney were similar among the 3 groups evaluated in this study.

Islet oxygen consumption rate dose predicts insulin independence for first clinical islet allotransplants

BACKGROUND

Human islet allotransplantation for the treatment of type 1 diabetes is in phase III clinical trials in the U.S. and is the standard of care in several other countries. Current islet product release criteria include viability based on cell membrane integrity stains, glucose-stimulated insulin release, and islet equivalent (IE) dose based on counts. However, only a fraction of patients transplanted with islets that meet or exceed these release criteria become insulin independent following 1 transplant. Measurements of islet oxygen consumption rate (OCR) have been reported as highly predictive of transplant outcome in many models.

METHOD

In this article we report on the assessment of clinical islet allograft preparations using OCR dose (or viable IE dose) and current product release assays in a series of 13 first transplant recipients. The predictive capability of each assay was examined and successful graft function was defined as 100% insulin independence within 45 days post-transplant.

RESULTS

OCR dose was most predictive of CTO. IE dose was also highly predictive, while glucoses stimulated insulin release and membrane integrity stains were not.

CONCLUSION

OCR dose can predict CTO with high specificity and sensitivity and is a useful tool for evaluating islet preparations prior to clinical human islet allotransplantation.

Age-based disparity in outcomes of intestinal transplants in pediatric patients

Outcomes of intestinal transplants (ITx; n = 977) for pediatric patients are examined using the United Network for Organ Sharing data from 1987 to 2009. Recipients were divided into four age groups: (1) <2 years of age (n = 569), (2) 2-6 years (n = 219), (3) 6-12 years (n = 121) and (4) 12-18 years (n = 68). Of 977 ITx, 287 (29.4%) were isolated ITx and 690 (70.6%) were liver and ITx (L-ITx). Patient survival for isolated ITx at 1, 3 and 5 years, 85.3%, 71.3% and 65.0%, respectively, was significantly better than L-ITx, 68.4%, 57.0% and 51.4%, respectively, (p = 0.0001); this was true for all age groups, except for patients <2 years of age. The difference in graft survival between isolated ITx and L-ITx was significant at 1 and 3 years (Wilcoxon test, p = 0.0012). After attrition analysis of graft survival of patients who survived past first year, 3 and 5 years, graft survival for L-ITx patient was significantly better than those for isolated ITx. Isolated ITx should be considered early before the onset of liver disease in children >2 with intestinal failure but is not advantageous in patients <2 years.

Long-term results after pancreas transplantation

With the advances in technique and immunosupression, not only the short- but the long-term outcomes of pancreas transplantation have improved significantly. This retrospective study describes the long-term outcomes of simultaneous pancreas and kidney (SPK) transplants, pancreas after kidney (PAK), and pancreas transplants alone (PTA). An overall analysis was performed for all deceased donor (DD) primary pancreas transplants performed in the United States between 1988 and 1999. In addition, the long-term outcome for pancreas transplants performed at the University of Minnesota (UM) was analyzed. For SPK transplants performed in the United States between 1998 and 1999, the half-life of the pancreas was almost 12 years, and was 12.5 years for kidneys. For SPK cases where the pancreas was functioning at 1 year, the half-lives of both the pancreas and the kidney grafts extended more than 14 years. The half-lives of solitary pancreas transplants were between 7 years for PAK and 9 years for PTA cases. For US solitary transplants with at least 1 year of graft function, the half-lives extended to almost 9 years. Pancreas transplants performed at the UM showed the same significant improvements over time. Of special interest is the excellent long-term graft function of pancreas transplants from a living donor, which in the early years clearly surpassed that of solitary DD pancreas transplants. A multivariate analysis showed that the factor with the highest impact on long-term graft function in all three transplant categories was the use of a young donor. In SPK cases, the most frequent reason for late graft loss was death with a functioning graft. In solitary pancreas transplants, most late graft losses were still due to immunological reasons.

Intestinal graft versus native liver cytokine expression in a rat model of intestinal transplantation: effect of donor-specific cell augmentation

INTRODUCTION

Immunomodulation by portal vein delivery of donor antigen reduces intestinal graft rejection. We investigated the impact of portal venous donor-specific cell augmentation (blood versus bone marrow) on cytokine expression in intestinal grafts versus native livers.

METHODS

Ten groups of intestinal transplants (brown Norway male to Lewis female rats) varied by (1). the type of donor-specific cell augmentation and (2). the use and dose of tacrolimus-based immunosuppression. Tissue samples for histologic analysis and cytokine mRNA analysis were obtained at designated time points.

RESULTS

Without immunosuppression, no type of cell augmentation reduced the rate of rejection. With immunosuppression, outcome was significantly better after portal donor-specific blood transfusion (versus bone marrow infusion). Irrespective of the type of cell augmentation, severe rejection caused strong intragraft expression of IL-1alpha, IL-1beta, IFN-gamma, and TNF-alpha; liver expression mainly involved TNF-alpha. Of note, nonimmunosuppressed, cell-augmented rats showed hardly any differences in cytokine expression in their grafts versus significant increases in their native livers. With immunosuppression, bone marrow infusion (versus blood transfusion) increased intragraft cytokine expression of IL-1alpha, IL-1beta, IFN-gamma, as well as TNF-alpha, and liver expression of IL-1beta.

CONCLUSIONS

(1). Rejection and donor-specific cell augmentation independently caused differences in intragraft versus native liver cytokine expression after intestinal transplants. (2). Portal donor-specific blood transfusion (versus bone marrow infusion) lowered the incidence of rejection and diminished intragraft cytokine up-regulation. (3). In our study, TNF-alpha appeared to be the cytokine most strongly associated with rejection.

Analysis of United States (US) and non-US pancreas transplants reported to the United network for organ sharing (UNOS) and the international pancreas transplant registry (IPTR) as of October 2001

As of October 10, 2001, > 17,000 pancreas transplant had been reported to the IPTR, > 11,500 in the US and > 4,700 outside the US. An era analysis of US cases from 1987 to 2001 showed a progressive improvement in outcome (p < 0.04), with pancreas transplant graft survival rates (GSRs) going from 75% to 83% at one year for SPK cases, from 50% to 78% for PAK cases, and from 49% to 78% for PTA cases. The improvements were due both to decreases in technical failure (TF) rates (from 14% to 7% in SPK, 23% to 8% in PAK, and 23% to 10% in PTA) and immunological failure rates (going from 7% to 2% for SPK, from 25% to 2% for PAK, and from 28% to 4% for PTA cases). The proportion of recipients > 45 years old increased from 5% to 25%, and the improved outcomes encompassed the older patients as well. In patients > 45 years old, SPK pancreas GSRs at one year increased from 74% to 80% (p < 0.007). Pancreas GSRs were also similar for recipients reported to have Type 1 or Type 2 diabetes (at one year, 84% and 83%, respectively for 1997-2001 SPK transplants), the latter designated in 5% of the recipients. Contemporary pancreas transplant outcomes were calculated separately for 1997-2001 US and non-US cases. US patient survival rates at one year were > or = 95% in each recipient category, with one year pancreas GSRs of 83% for SPK (n = 3885), 79% for PAK (n = 630), and 78% for PTA (n = 240) (p = 0.0002). The immunological graft failure rates for 1997-2001 US SPK, PAK and PTA cases were 4%, 6%, and 8% at one year (p = 0.0001). There was a progressive increase in the use of ED (as opposed to BD) for duct management, to 67% for 1997-2001 US SPK transplants, 51% for PAK and 42% for PTA. Of US SPK ED transplants, 22% had venous drainage via the portal system. US pancreas GSRs were not significantly different for 1997-2001 ED (n = 2,519) and BD (n = 1,260) US SPK transplants (82% and 85%, respectively, at one year), nor was there a difference in pancreas GSRs for systemic (n = 1,958) versus portal (n = 557) venous-drained ED SPK transplants (82% vs. 84% at one year). Kidney GSRs were slightly higher for ED versus BD US SPK cases, 93% versus 91% at one year (p = 0.03). Duct management did matter for solitary (PAK and PTA) pancreas transplants. Pancreas GSRs for PAK recipients were 85% at one year for BD (n = 316) versus 74% for ED (n = 303) US transplants (p < 0.02); for PTA 81% (n = 168) versus 74% (p > or = 0.37). However, BD transplants were associated with a 12% conversion rate to ED by two years posttransplant. Recipient age made little difference for outcome in any category. Indeed, in the PTA category GSRs were significantly higher for US recipients > 45 years old (n = 66) than 21-45 years old (n = 216), 85% versus 77% at 1 year (p < or = 0.10). TAC + MMF was the dominant maintenance immunosuppressant for 1999-2001 US cases (> 70%). In an analysis of outcome according to type of anti-T-cell antibody agents (depleting vs. non-depleting vs. none) for induction therapy in TAC + MMF treated recipients, there were no differences in GSRs in any of the categories. In regard to non-US cases, the overwhelming majority were in the SPK category (n = 1,649 for 1997-2001), with a one year pancreas GSR of 82%, not significantly different than for US cases. In summary, pancreas transplant graft survival rates were nearly 80% at one year in recipients of solitary (PAK and PTA) pancreas transplants, and > 80% in SPK recipients for 1997-2001 cases. The outcome continues to improve as increasing numbers of solitary pancreas transplants are done.

Pancreas transplant outcomes for United States (US) cases reported to the United Network for Organ Sharing (UNOS) and non-US cases reported to the International Pancreas Transplant Registry (IPTR) as of October, 2000

As of October 2000, > 15,000 pancreas transplant had been reported to the IPTR, > 11,000 in the US and > 4,000 outside the US. An era analysis of US cases from 1987-2000 showed a progressive improvement in outcome (p < 0.04), with pancreas transplant graft survival rates (GSRs) going from 72% to 82% at one year for SPK cases, from 52% to 74% for PAK cases, and from 47% to 76% for PTA cases. The improvements were due both to decreases in technical failure (TF) rates (overall from 16% to 7%) and immunological failure rates (going from 8% to 2% for SPK, from 27% to 6% for PAK, and from 37% to 12% for PTA cases). The proportion of recipients > 45 years old increased from 5% to 25%, and the improved outcomes encompassed the older patients as well. In patients > 45 years old, SPK pancreas GSRs at one year increased from 62% to 78% (p < 0.002). Pancreas GSRs were also similar for recipients reported to have Type 1 or Type 2 diabetes (at one year, 84% and 83%, respectively for 1996-2000 SPK transplants), the latter designated in 3% of the recipients. Contemporary pancreas transplant outcomes were calculated separately for 1996-2000 US and non-US cases. US patient survival rates at one year were > or = 94% in each recipient category, with one-year pancreas GSRs of 84% for SPK (n = 3,697), 76% for PAK (n = 696), and 71% for PTA (n = 300) (p = 0.0001). The immunological graft failure rates for 1996-2000 US SPK, PAK and PTA cases were 2%, 6%, and 8% at one year (p = 0.001). There was a progressive increase in the use of ED (as opposed to BD) for duct management, to > 50% for 1996-2000 US SPK transplants. Approximately 20% of US SPK ED transplants had venous drainage via the portal system. Pancreas GSRs were not significantly different for 1996-2000 ED (n = 1,940) and BD (n = 1,541) US SPK transplants (83% and 84%, respectively, at one year), nor was there a difference in pancreas GSRs for systemic (n = 1,509) versus portal (n = 411) venous drained ED SPK transplants (83% for both at one year). Kidney GSRs were also not significantly different for ED versus BD US SPK cases, 93% versus 91% at one year (p = 0.13). Duct management did matter for solitary (PAK and PTA) pancreas transplants (P < or = 0.07). Pancreas GSRs for PAK recipients were 77% at one year for BD (n = 359) versus 67% for ED (n = 306) US transplants; for PTA 75% (n = 174) versus 63%. However, BD transplants were associated with a 12% conversion rate to ED by 2 years after transplantation. Analyses of outcome by immunosuppression for US cases showed pancreas GSRs ranged from 77% to 88% at one year, but were highest in SPK recipients given anti-T-cell agents for induction and CSA-MMF for maintenance immunosuppression. For PAK and PTA recipients, those given anti-T-cell agents for induction and TAC-MMF for maintenance immunosuppression had the highest GSRs: 78% and 78%, respectively, at one year for BD pancreas transplants (vs. 85% in BD SPK recipients similarly immunosuppressed, P > 0.08). In regard to non-US cases, the overwhelming majority were in the SPK category (n = 676 for 1996-2000), with a one-year pancreas GSR of 84%, not significantly different than for US cases. In summary, pancreas transplant graft survival rates were > 70% in the solitary (PAK and PTA) and > 80% in SPK recipients during the last 4 years of the 20th century. These outcomes culminate a third of a century of application for the treatment of diabetes mellitus.

Pancreas after kidney transplants

BACKGROUND

For certain uremic diabetic patients, a sequential transplant of a kidney (usually from a living donor) followed by a cadaver pancreas has become an attractive alternative to a simultaneous transplant of both organs. The purpose of this study was to compare outcomes with simultaneous pancreas-kidney (SPK) versus pancreas after kidney (PAK) transplants to determine advantages and disadvantages of the two procedures.

METHODS

Between January 1, 1994, and June 30, 2000, we performed 398 cadaver pancreas transplants at our center. Of these, 193 were SPK transplants and 205 were PAK transplants. We compared these two groups with regard to several endpoints, including patient and graft survival rates, surgical complications, acute rejection rates, waiting times, length of hospital stay, and quality of life.

RESULTS

Overall, surgical complications were more common for SPK recipients. The total relaparotomy rate was 25.9% for SPK recipients versus 15.1% for PAK recipients (P = 0.006). Leaks, intraabdominal infections, and wound infections were all significantly more common in SPK recipients (P = 0.009, P = 0.05, and P = 0.01, respectively, versus PAK recipients). Short-term pancreas graft survival rates were similar between the two groups: at 1 year posttransplant, 78.0% for SPK recipients and 77.9% for PAK recipients (P = not significant). By 3 years, however, pancreas graft survival differed between the two groups (74.1% for SPK and 61.7% for PAK recipients), although this did not quite reach statistical significance (P = 0.15). This difference in graft survival seemed to be due to increased immunologic losses for PAK recipients: at 3 years posttransplant, the incidence of immunologic graft loss was 16.2% for PAK versus 5.2% for SPK recipients (P = 0.01). Kidney graft survival rates were, however, better for PAK recipients. At 3 years after their kidney transplant, kidney graft survival rates were 83.6% for SPK and 94.6% for PAK recipients (P = 0.001). The mean waiting time to receive the pancreas transplant was 244 days for SPK and 167 days for PAK recipients (P = 0.001).

CONCLUSIONS

PAK transplants are a viable option for uremic diabetics. While long-term pancreas graft results are slightly inferior to SPK transplants, the advantages of PAK transplants include the possibility of a preemptive living donor kidney transplant, better long-term kidney graft survival, significantly decreased waiting times, and decreased surgical complication rates. Use of a living donor for the kidney transplant expands the donor pool. Improvements in immunosuppressive regimens will hopefully eliminate some of the difference in long-term pancreas graft survival between SPK and PAK transplants.

Experimental short-term immunosuppression after bowel transplantation and donor-specific bone marrow infusion

HYPOTHESIS

We previously showed in a large animal pig model that unmodified donor-specific bone marrow infusion (DSBMI) did not facilitate total bowel engraftment; in contrast, it increased the risks of rejection, infection, and graft-vs-host disease (GVHD) posttransplant. We hypothesize that continuous immunosuppression, in combination with DSBMI, might contribute to-or even trigger-these unwarranted immune responses by both host and graft; therefore, discontinuing immunosuppression might decrease these risks and prolong survival.

METHODS

Six groups of outbred, mixed lymphocyte culture-reactive pigs underwent a total (small and large) bowel transplant: group 1, nonimmunosuppressed control pigs (n = 5); group 2, nonimmunosuppressed DSBMI pigs (n = 6); group 3, tacrolimus (indefinite) pigs (n = 7); group 4, tacrolimus (indefinite) plus DSBMI pigs (n = 7); group 5, tacrolimus (10 days only) pigs (n = 5); and group 6, tacrolimus (10 days only) plus DSBMI pigs (n = 6).

RESULTS

The combination of short-term immunosuppression and DSBMI (group 6) significantly prolonged survival, compared with short-term immunosuppression only (group 5) or DSBMI only (group 2). Short-term immunosuppression and DSBMI (group 6) did not prolong overall survival, compared with indefinite immunosuppression with (group 4) or without (group 3) DSBMI: survival rates at 7, 14, and 28 days posttransplant were 100%, 100%, and 67% in group 6; 100%, 100%, and 71% in group 3; and 100%, 67%, and 47% in group 4 (P =.14). Short-term immunosuppression and DSBMI (group 6) increased the incidence of rejection, infection, and GVHD, compared with indefinite immunosuppression without (but not with) DSBMI.

CONCLUSIONS

Short-term immunosuppression and DSBMI did not prolong survival and did not reduce the incidence of death from rejection, infection, or GVHD, compared with indefinite immunosuppression without DSBMI. But short-term immunosuppression and DSBMI resulted in a lower incidence of death from infection and GVHD, compared with indefinite immunosuppression and DSBMI. When immunosuppression was discontinued 10 days posttransplant, the effect of DSBMI was insufficient to avert death from rejection.

CLINICAL RELEVANCE

The clinical results of bowel transplantation trail those of other solid organ transplants. It reduced the rates of infection and GVHD. Our study shows that systemically infused donor-specific bone marrow with short-term or indefinite immunosuppression does not improve outcome after bowel transplantation. It seems necessary to modify the time, dosing, routing, and/or composition of donor-specific bone marrow before it can be successfully used in clinical bowel transplantation.

Bone marrow augmentation in kidney transplantation: a large animal study

Specific immunomodulatory strategies are required to eliminate the need for lifelong dependence on debilitating immunosuppressants. One proposed strategy is to simultaneously transplant the kidney and infuse donor-specific bone marrow cells. We prospectively studied the effect of unmodified donor-specific bone marrow infusion (DSBMI) on rejection, infection, graft-versus-host disease (GvHD), and graft survival. We performed 57 kidney transplants in mixed lymphocyte culture (MLC)-reactive, outbred pigs. The groups of recipient pigs differed according to the use of (1) indefinite versus short-term tacrolimus-based immunosuppression, (2) DSBMI, and (3) recipient preconditioning (RPC: whole body irradiation with 400 rads on day 0 and horse anti-pig thymocyte globulin (ATG) on days -2, -1, and 0). In all, we studied eight groups: group 1, nonimmunosuppressed control pigs (n = 8); group 2, nonimmunosuppressed DSBMI pigs (n = 7); group 3, nonimmunosuppressed RPC + DSBMI pigs (n = 5); group 4, tacrolimus (indefinite) pigs (n = 11); group 5, tacrolimus (10 days only) pigs (n = 5); group 6, DSBMI + tacrolimus (indefinite) pigs (n = 8); group 7, DSBMI + tacrolimus (10 days only) pigs (n = 6); and group 8, RPC + DSBMI + tacrolimus (indefinite) pigs (n = 7). DSBMI alone (group 2) or in combination with RPC (group 3) did not prolong graft survival, as compared with nonimmunosuppressed controls (group 1). In groups 1, 2, and 3, all but one pig died from rejection; in group 3 only, 45% of the pigs died from concurrent infection or GvHD, indicating that RPC in combination with DSBMI aggravated the risk of generalized infection and GvHD. Post-transplant immunosuppression--irrespective of indefinite or short-term administration--was required for prolonged graft survival. With indefinite use of immunosuppression, graft survival rates and death rates from rejection were not different for pigs with (group 6) versus without (group 4) DSBMI; however, the death rate from infection was higher in group 6, suggesting that the bone marrow inoculum increased the risk of systemic infection. With short-term use of immunosuppression, graft survival rates were higher and death rates from rejection lower for pigs with (group 7) versus without (group 5) DSBMI. But DSBMI and short-term immunosuppression (group 7) failed to prolong survival beyond that achieved with indefinite immunosuppression (groups 4 and 6). Although the combination of DSBMI and short-term immunosuppression (group 7) reduced the risk of infection, it did not avert severe rejection. The addition of RPC to DSBMI and indefinite immunosup- pression (group 8) significantly decreased graft survival, as compared with groups 4, 6, and 7. It also increased the incidence of death from rejection, GvHD, and infection, or a combination thereof. Unmodified DSBMI did not prolong graft survival after kidney transplantation, nor did it decrease the incidence of rejection. But it aggravated the risk of GvHD and infection. Short-term immunosuppression with DSBMI reduced the incidence of death from infection or GvHD, but it resulted in a higher incidence of death from rejection (as compared with indefinite use of immunosuppression). RPC, combined with DSBMI and indefinite immunosuppression, increased the death rate from rejection, GvHD, infection, or a combination thereof. In this large animal study, the effect of unmodified DSBMI has been disappointing. The search continues for the optimal way to successfully perform bone marrow augmentation in solid organ transplants.

Pancreas transplantation for treatment of diabetes mellitus

Pancreas transplantation is the only treatment for type I diabetes mellitus that can induce an insulin-independent normoglycemic state. Because of the need for immunosuppression, it has been most widely applied in uremic diabetic recipients of kidney transplant with a high success rate, particularly when done as a simultaneous (SPK) procedure (insulin independence > 80% at 1 year) with patient and kidney graft survival rates equivalent to or higher than in those who receive a kidney transplant alone. The results of solitary pancreas transplants (PAK in nephropathic diabetic recipients or PTA in nonuremic recipients) have also dramatically improved; 1-year graft survival rates are more than 80% and 70%, respectively, with the new immunosuppressants tacrolimus and mycophenolate mofetil. Multiple factors are important for successful application of pancreas transplantation, as summarized in this review.

Lessons learned from more than 1,000 pancreas transplants at a single institution

OBJECTIVE

To determine outcome in diabetic pancreas transplant recipients according to risk factors and the surgical techniques and immunosuppressive protocols that evolved during a 33-year period at a single institution.

SUMMARY BACKGROUND DATA

Insulin-dependent diabetes mellitus is associated with a high incidence of management problems and secondary complications. Clinical pancreas transplantation began at the University of Minnesota in 1966, initially with a high failure rate, but outcome improved in parallel with other organ transplants. The authors retrospectively analyzed the factors associated with the increased success rate of pancreas transplants.

METHODS

From December 16, 1966, to March 31, 2000, the authors performed 1,194 pancreas transplants (111 from living donors; 191 retransplants): 498 simultaneous pancreas-kidney (SPK) and 1 simultaneous pancreas-liver transplant; 404 pancreas after kidney (PAK) transplants; and 291 pancreas transplants alone (PTA). The analyses were divided into five eras: era 0, 1966 to 1973 (n = 14), historical; era 1, 1978 to 1986 (n = 148), transition to cyclosporine for immunosuppression, multiple duct management techniques, and only solitary (PAK and PTA) transplants; era 2, 1986 to 1994 (n = 461), all categories (SPK, PAK, and PTA), predominantly bladder drainage for graft duct management, and primarily triple therapy (cyclosporine, azathioprine, and prednisone) for maintenance immunosuppression; era 3, 1994 to 1998 (n = 286), tacrolimus and mycophenolate mofetil used; and era 4, 1998 to 2000 (n = 275), use of daclizumab for induction immunosuppression, primarily enteric drainage for SPK transplants, pretransplant immunosuppression in candidates awaiting PTA.

RESULTS

Patient and primary cadaver pancreas graft functional (insulin-independence) survival rates at 1 year by category and era were as follows: SPK, era 2 (n = 214) versus eras 3 and 4 combined (n = 212), 85% and 64% versus 92% and 79%, respectively; PAK, era 1 (n = 36) versus 2 (n = 61) versus 3 (n = 84) versus 4 (n = 92), 86% and 17%, 98% and 59%, 98% and 76%, and 98% and 81%, respectively; in PTA, era 1 (n = 36) versus 2 (n = 72) versus 3 (n = 30) versus 4 (n = 40), 77% and 31%, 99% and 50%, 90% and 67%, and 100% and 88%, respectively. In eras 3 and 4 combined for primary cadaver SPK transplants, pancreas graft survival rates were significantly higher with bladder drainage (n = 136) than enteric drainage (n = 70), 82% versus 74% at 1 year (P =.03). Increasing recipient age had an adverse effect on outcome only in SPK recipients. Vascular disease was common (in eras 3 and 4, 27% of SPK recipients had a pretransplant myocardial infarction and 40% had a coronary artery bypass); those with no vascular disease had significantly higher patient and graft survival rates in the SPK and PAK categories. Living donor segmental pancreas transplants were associated with higher technically successful graft survival rates in each era, predominately solitary (PAK and PTA) in eras 1 and 2 and SPK in eras 3 and 4. Diabetic secondary complications were ameliorated in some recipients, and quality of life studies showed significant gains after the transplant in all recipient categories.

CONCLUSIONS

Patient and graft survival rates have significantly improved over time as surgical techniques and immunosuppressive protocols have evolved. Eventually, islet transplants will replace pancreas transplants for suitable candidates, but currently pancreas transplants can be applied and should be an option at all stages of diabetes. Early transplants are preferable for labile diabetes, but even patients with advanced complications can benefit.

Analyses of pancreas transplant outcomes for United States cases reported to the United Network for Organ Sharing (UNOS) and non-US cases reported to the International Pancreas Transplant Registry (IPTR)

As of September 1999, almost 13,000 pancreas transplants had been reported to the IPTR, > 9,000 in the US and > 3,000 outside the US. An era analysis of US cases from 1987 to 1997 showed a progressive improvement in outcome (p < 0.04), with pancreas transplant graft survival rates (GSRs) going from 74% to 85% at one year for SPK cases, from 56% to 75% for PAK cases, and from 50% to 69% for PTA cases. The improvements were due both to decreases in technical failure (TF) rates (overall from 16% to 8%) and immunological failure rates (going from 6% to 2% for SPK, from 23% to 7% for PAK, and from 35% to 9% for PTA cases). The proportion of recipients > 44 years old increased from 5% to 24%, and the improved outcomes encompassed the older patients as well. In patients > 44 years old, SPK pancreas GSRs at one year increased from 69% for 1987-89 cases to 79% for 1996-97 cases (p < 0.03). Pancreas GSRs were also similar for recipients reported to have Type I or Type II diabetes (at 1 year, 84% and 81%, respectively, for 1994-99 SPK transplants), the latter designated in 3% of the recipients. Contemporary pancreas transplant outcomes were calculated separately for 1996-99 US and non-US cases. US patient survival rates at one year were > or = 95% in each recipient category, with one year pancreas GSRs of 84% for SPK (n = 2,502), 76% for PAK (n = 404), and 72% for PTA (n = 176) (p = 0.0001). The immunological graft failure rates for 1996-99 US SPK, PAK and PTA cases were 2%, 6%, and 10% at one year (p = 0.001). There was a progressive increase in the use of ED (as opposed to BD) for duct management, up to nearly 60% of US pancreas transplants by 1998. Approximately 18% of SPK ED transplants had venous drainage via the portal system. Pancreas GSRs were not significantly different for 1996-99 ED (n = 1,170) and BD (n = 1,203) US SPK transplants (84% and 85%, respectively, at 1 year), nor was there any difference in pancreas GSRs for systemic (n = 437) versus portal (n = 194) venous drained ED SPK transplants (84% and 83%, respectively, at 1 year). Interestingly, kidney GSRs were significantly higher for ED versus BD US SPK cases, 93% versus 84% at one year (p = 0.003). Duct management did matter for solitary (PAK and PTA) pancreas transplants. PAK pancreas GSRs were 80% at one year for BD (n = 238) versus 68% for ED (n = 156) US transplants. PTA pancreas GSRs were 78% at one year for BD (n = 98) versus 63% for ED (n = 73) US transplants. However, BD transplants were associated with a 12% conversion rate to ED by 2 years after transplantation. Analyses of outcome by immunosuppression for US cases showed pancreas GSRs to be higher in SPK recipients given MMF (87% at 1 year) than in those who were not (76% at 1 year). For PAK and PTA recipients, those given anti-T cell for induction and TAC and MMF for maintenance immunosuppression had the highest GSRs: 86% and 83%, respectively, at one year for BD pancreas transplants; not significantly different from the pancreas GSR (87% at 1 year) in BD SPK recipients also given anti-T cell for induction and TAC and MMF for maintenance immunosuppression. Analyses of US pancreas transplant outcome according to HLA matching showed no effect at all in the SPK category, while for PAK and PTA transplants an effect was seen at the A and B loci, strongest at the B loci. Matching for at least one antigen at both loci was associated with one-year pancreas GSRs of 85% for PAK and 74% for PTA, versus 70% and 60%, respectively, at one year for those who were not matched for at least one antigen at both the A and B loci. In regard to non-US cases, the overwhelming majority were in the SPK category (n = 528 for 1996-99), with one-year pancreas GSR of 79%, not significantly different from US cases. Approximately 40% of non-US SPK cases were ED (n = 204), and, as in the US, the pancreas GSRs were similar for ED and BD transplants in this category. (ABSTRACT TRUNCATED)

Optimal timing for a pancreas transplant after a successful kidney transplant

BACKGROUND

For certain uremic, diabetic patients, a sequential transplant of a kidney (usually from a living donor) followed by a cadaver pancreas has become an attractive option. But how long to wait after the kidney transplant before proceeding with a pancreas transplant is unclear. We studied outcomes in recipients of a pancreas at varying times after a kidney to determine the optimal timing for the second transplant.

METHODS

We compared pancreas after kidney (PAK) transplants performed early (< or =4 months) and late (>4 months) after the kidney transplant to determine any significant differences in surgical complications or outcomes between the two groups.

RESULTS

Between January 1, 1994, and September 30, 1998, we performed 123 cadaver PAK transplants. Of these, 25 (20%) were early and 98 (80%) were late. Characteristics of the two recipient groups were similar. We found no significant differences in outcome between the two groups. The incidence of surgical complications (bleeding, leaks, thrombosis, infections) and of opportunistic infections (such as cytomegalovirus) did not significantly differ between the two groups. Graft and patient survival rates were also equivalent (P=NS). The incidence of acute rejection by 3 months posttransplant was 20% in both groups.

CONCLUSION

The timing of the pancreas transplant for PAK recipients does not seem to influence outcome. As long as an acceptable organ is available and the recipient is clinically stable, a PAK transplant can be performed relatively soon after the kidney transplant.

Decreased surgical risks of pancreas transplantation in the modern era

OBJECTIVE

To document the decreased incidence of surgical complications after pancreas transplantation in recent times.

SUMMARY BACKGROUND DATA

Compared with other abdominal transplants, pancreas transplants have historically had the highest incidence of surgical complications. However, over the past few years, the authors have noted a significant decrease in the incidence of surgical complications.

METHODS

The authors studied the incidence of early (<3 months after transplant) surgical complications (e.g., relaparotomy, thrombosis, infections, leaks) after 580 pancreas transplants performed during a 12-year period. Patients were analyzed and compared in two time groups: era 1 (June 1, 1985, to April 30, 1994, n = 367) and era 2 (May 1, 1994, to June 30, 1997, n = 213).

RESULTS

Overall, surgical complications were significantly reduced in era 2 compared with era 1. The relaparotomy rate decreased from 32.4% in era 1 to 18.8% in era 2. Significant risk factors for early relaparotomy were donor age older than 40 years and recipient obesity. Recipients with relaparotomy had significantly lower graft survival rates than those without relaparotomy, but patient survival rates were not significantly different. A major factor contributing to the lower relaparotomy rate in era 2 was a significant decrease in the incidence of graft thrombosis; the authors believe this lower incidence is due to the routine use of postoperative low-dose intravenous heparin and acetylsalicylic acid. The incidence of bleeding requiring relaparotomy did not differ between the two eras. Older donor age was the most significant risk factor for graft thrombosis. The incidence of intraabdominal infections significantly decreased between the two eras; this decrease may be due to improved prophylaxis regimens in the first postoperative week.

CONCLUSIONS

Although a retrospective study has its limits, the results of this study, the largest single-center experience to date, show a significant decrease in the surgical risk associated with pancreas transplants. Reasons for this decrease are identification of donor and recipient risk factors, better prophylaxis regimens, refinements in surgical technique, and improved immunosuppressive regimens. These improved results suggest that more widespread application of pancreas transplantation is warranted.

Steroid withdrawal in pancreas transplant recipients

BACKGROUND

Numerous studies of steroid withdrawal have been carried out in kidney and liver transplant recipients, but only a few in pancreas transplant recipients. Yet, pancreas transplant recipients could have significant long-term benefits from steroid withdrawal.

METHODS

We performed a retrospective analysis to determine the feasibility of steroid withdrawal in pancreas transplant recipients.

RESULTS

Of 360 recipients who underwent a pancreas transplant between January 1, 1994 and June 30, 1998, 14 attempted steroid withdrawal (12 simultaneous pancreas-kidney [SPK]; 2 pancreas transplant alone [PTA]). Reasons for steroid withdrawal were bone fractures (n = 3), psychiatric disorders (n = 2), severe acne (n = 1), recurrent infections (n = 4), and problems with hypercholesterolemia or hypertension (n = 4). All 14 were maintained on tacrolimus and mycophenolate mofetil (MMF) immunosuppression, except for 1 who was on tacrolimus and azathioprine (AZA). Of the 14 recipients, 11 had no episodes of acute rejection before steroid withdrawal. The remaining 3 had one or more acute rejection episodes. Of the 14 recipients, 10 (72%) currently remain off steroids (mean follow-up 18 months, range 5-51 months). However, 4 recipients have resumed steroids: 2 after an acute rejection episode (at 2 and 21 months post-withdrawal) and 2 because of leukopenia (WBC < 3000) and an inability to tolerate full-dose MMF. Steroid withdrawal was unsuccessful in both PTA recipients and in 2 of the 12 SPK recipients. All 14 recipients currently have a functioning pancreas graft. However, 1 of the SPK recipients, in whom steroid withdrawal failed, has developed chronic kidney rejection and is now back on hemodialysis awaiting a retransplant.

CONCLUSION

Steroid withdrawal is possible in up to 70% of pancreas transplant recipients. Further studies are necessary to define ideal candidates for steroid withdrawal. Based on the results of this analysis, we have launched a prospective, randomized trial of steroid withdrawal in pancreas transplant recipients.

Analysis of United States (US) and non-US pancreas transplants as reported to the International Pancreas Transplant Registry (IPTR) and to the United Network for Organ Sharing (UNOS)

As of November 1998, more than 11,000 pancreas transplants had been reported to the IPTR, including more than 8,800 US and more than 2,600 non-US cases. The 1994-98 cases (> 4,500) were analyzed, including more than 4,000 US and more than 500 non-US transplants. For all US 1994-98 SPK transplants (n = 3,409), one-year patient, pancreas and kidney graft survival rates were 94%, 90% and 83%, respectively; for all PAK cases (n = 375), one-year patient and graft survival rates were 95% and 71%; and for all PTA cases (n = 181), one-year patient and graft survival rates were 95% and 64%, respectively. Recipient age had only a small impact on outcome, with one-year patient survival rates for all recipients < 45 years of 95% (n = 3,215) versus 91% for those > or = 45 years old (n = 758) (p = 0.005). Pancreas graft survival rates at one year for those < 45 versus > or = 45 years old were 84% versus 78% in the SPK (p < 0.02), 70% versus 78% in the PAK (p = 0.13), and 62% versus 79% in the PTA (p = 0.23) categories, respectively). Nearly one-third of US pancreas transplants for 1994-98 were done by the ED drainage technique. For SPK transplants, the one-year pancreas graft survival rate was 83% for BD (n = 2,369) and 82% for ED (n = 912) (p < or = 0.09). For PAK and PTA transplants, pancreas graft survival rates were significantly higher with BD, 74% (n = 261) and 68% (n = 115), respectively, at one year. The drawback for BD was the need for conversion to ED in 7% of the cases at one year and 11% at 2 years. For TS transplants, the pancreas graft loss due to rejection was very low for SPK transplants, 2% at one year versus 9% for PAK and 15% for PTA cases. The various initial maintenance immunosuppressive regimens (Tac + MMF, Tac + Aza, CsA + MMF, CsA + Aza) resulted in only minor differences in pancreas graft survival rates in the SPK cases (80-86% at 1 year), but in PAK and PTA cases the Tac + MMF combination was associated with significantly higher pancreas graft survival rates. For BD PAK transplant recipients given Tac + MMF, the one-year pancreas graft survival rate was 83% (n = 100). For the corresponding BD PTA group it was 75% (n = 44). For non-US cases the outcomes were similar. For non-US SPK transplants (n = 586), one-year patient, kidney and pancreas graft survival rates were 93%, 85% and 81%, respectively. Cox multivariate analyses and logistical regression were done in each recipient category to assess the factors that influence pancreas graft loss. BD was associated with a significantly lower risk than ED in all categories. Increasing donor age was a risk factor in most categories. MMF was associated with a decreased risk for graft loss in the SPK category, and Tac in the PAK and PTA categories.

Pancreas transplants for United States (US) and non-US cases as reported to the International Pancreas Transplant Registry (IPTR) and to the United Network for Organ Sharing (UNOS)

As of November 1997 more than 9,800 pancreas transplants had been reported to the IPTR, including more than 7,400 US and more than 2,400 non-US cases. Cases reported since the inception of UNOS in 1987 (more than 6,800 in the US and more than 2,000 from outside the US) were analyzed, with emphasis on 1994-97 cases. In the US, for all 1994-97 SPK transplants (n = 2,585), one-year patient, pancreas and kidney graft survival rates were 94%, 82% and 90%, respectively; for all PAK cases (n = 230), patient and graft survival rates at one year were 95% and 71%; and for all PTA cases (n = 117), patient and graft survival rates at one year were 93% and 62%, respectively. The 1994-97 pancreas survival rates in all categories were significantly higher than in previous eras. Analysis of bladder versus enteric drainage (BD vs ED) was made only for 1994-97 SPK cases since there were too few solitary ED cases for a comparison. One-year pancreas survival rates (all causes of failure included) were 83% for BD (n = 1,995) versus 80% for ED (n = 456) cases (p = NS). However, nearly 20% of SPK BD grafts had been converted to ED by 2 years. The pancreas retransplant success rates have also significantly increased over time. For 1994-97 pancreas retransplants (n = 92), the one-year graft survival rate was 72%. The technical failure (TF) rate for pancreas transplants has declined over time. For 1994-96 BD cases, the TF rate was 8% in SPK (n = 1,995), 13% in PAK (n = 174) and 11% in PTA (n = 90) cases. For SPK ED cases (n = 456) the TF rate was 11% (p = 0.06 vs SPK BD). The most common cause of technical loss was graft thrombosis, 5.5% for SPK, 10.2% for PAK and 6.7% for PTA. The TF rates were significantly higher in grafts from older (> 45 yrs) donors and donors who died from cardiovascular disease. The immunological graft loss rate has also significantly declined in all categories. For 1994-97, technically successful (TS) cases (DWFG censored), the rejection loss rate at one year was 2% in the SPK (n = 2,234), 9% in the PAK (n = 154), and 16% in the PTA (n = 78) categories. Cox multivariate analyses were done in each recipient category to assess for factors that influence risks of pancreas graft loss. Increasing donor age was a risk factor in all categories. HLA mismatching was important only in the solitary (PAK and PTA) categories. FK506 use was associated with a positive effect in all categories, as was MMF in the SPK category.

Conversion from bladder to enteric drainage after pancreaticoduodenal transplantations

BACKGROUND

Bladder drainage is the most common technique for managing the exocrine secretions of pancreaticoduodenal grafts. However, bladder drainage can cause urinary, pancreatic, and metabolic complications that may require conversion to enteric drainage. With enteric drainage, urinary amylase levels cannot be monitored as a marker for rejection. After enteric conversion, rejection is the major cause of graft loss. Timing the conversion to reduce immunologic graft loss would greatly improve patient and graft survival rates. Our study was designed to assess the incidence of, indications for, and complications of converting from bladder to enteric drainage after pancreaticoduodenal transplantations.

METHODS

We retrospectively reviewed our experience with 80 recipients who underwent enteric conversion. We studied the recipient category, the interval from transplantation to conversion, the interval from the last rejection episode to conversion, the indications for conversion, the type of enteric drainage at conversion (loop versus Roux-en-Y), the results of the conversion, and postconversion complications.

RESULTS

The major indications for conversion were metabolic acidosis (n = 26, 33%), recurrent urinary tract infections (UTIs) (n = 16, 20%), reflux pancreatitis (n = 15, 19%), and hematuria (n = 12, 15%). For most recipients, their symptoms resolved after conversion (n = 76, 95%). The cumulative probability of undergoing conversion was 13% at 12 months, 21% at 36 months, and 25% at 60 months. Of the recipients with surgical complications after conversion (n = 12, 15%), one lost his graft as a result of pancreatitis. Overall, of the 80 recipients who underwent conversion, 12 (15%) lost their graft, most due to rejection (n = 8, 75%). Immunologic graft loss was highest for recipients of pancreas transplants alone who underwent conversion < or = 6 months after transplantation or < or = 1 year after their last rejection episode.

CONCLUSIONS

Enteric conversion is safe and therapeutic in recipients with complications related to the exocrine secretions of bladder-drained pancreas grafts. After conversion, rejection accounted for 75% of the grafts lost. However, waiting at least 1 year after the last rejection episode significantly reduced immunologic graft loss.

Mycophenolate mofetil in pancreas transplantation

BACKGROUND

Mycophenolate mofetil (MMF) has been shown to decrease the incidence of acute rejection episodes after kidney transplantation. The use of MMF along with tacrolimus for > or =1 year after pancreas transplantation has not been studied in a large single-center analysis.

METHODS

Between July 1, 1995 and June 30, 1997, both MMF and tacrolimus were given to 120 pancreas transplant recipients. By category, 61 underwent simultaneous pancreas-kidney transplantation (SPK); 44 underwent pancreas transplantation after previous kidney transplantation (PAK); and 15 underwent pancreas transplantation alone (PTA). By donor source, 86% of the grafts were from a cadaver, and 14% were from a living-related donor. Induction therapy was with MMF, tacrolimus, prednisone, and antithymocyte globulin (n=109) or OKT3 (n=2). Until oral intake was resumed, recipients initially received intravenous azathioprine. Side effects were as follows: gastrointestinal (GI) toxicity in 53% of recipients receiving combined MMF and tacrolimus therapy; bone marrow toxicity in 24% of recipients receiving MMF alone; nephrotoxicity in 18% and neurotoxicity in 11% of recipients receiving tacrolimus alone. We did a matched-pair analysis to compare outcome in MMF versus azathioprine recipients, using the database of the International Pancreas Transplant Registry. Matching criteria included transplantation category, transplantation number, recipient and donor age, duct management, HLA typing, and transplantation year.

RESULTS

One-year patient survival rates were 98% for SPK, 98% for PAK, and 100% for PTA (P=NS). For SPK recipients, 1-year pancreas graft survival rates were 86% with MMF versus 79% with azathioprine (P=NS); kidney graft survival rates were 96% with MMF versus 86% with azathioprine (P=NS). The incidence of first rejection episodes at 1 year was significantly lower for MMF recipients (15% with MMF versus 43% with azathioprine) (P = 0.0003). For recipients of solitary pancreas transplants (PTA and PAK), we found no difference in graft survival rates between MMF and azathioprine. The conversion rate from MMF to azathioprine at 1 year was 14% for SPK recipients, 26% for PAK, and 39% for PTA (P < 0.007). The most common reason for conversion was GI toxicity, in particular for nonuremic (PTA) or posturemic (PAK) recipients. The rates of posttransplant infection and lymphoproliferative disease were low for recipients on MMF and tacrolimus.

CONCLUSIONS

The combination of MMF and tacrolimus after pancreas transplantation is highly effective and safe. For SPK recipients, the incidence of acute reversible rejection episodes was significantly lower with MMF than with azathioprine. The conversion rate from MMF to azathioprine because of GI toxicity was lowest for SPK and highest for PTA recipients.

Pancreas transplantation: a review

Pancreas transplantation is now performed as a routine treatment for uremic diabetic recipients of kidney transplants either simultaneously with or after the kidney. Such patients are obligated to immunosuppression and with a successful pancreas transplant can achieve insulin independence as well as a dialysis-free state. Pancreas transplants alone are less commonly applied because of the need for immunosuppression, but the trade off to achieve an insulin-independent state may be worthwhile for individual patients, particularly those who are labile with hypoglycemic unawareness. This option should certainly be a part of the treatment armentation of the modern diabetologist. A positive effect on secondary complications will certainly occur with an early transplant, and even late can have an impact as has been shown for neuropathy. Whether the simpler procedure of islet transplantation will replace pancreas transplants remains to be seen. Of more than 200 islet allografts performed in the 1990s, less than 10% of the recipients have achieved insulin independence at 1 year. Clinical islet trials are ongoing but limited to patients who accept a low individual probability of success to assist in development, or to those in whom the surgical risks of a pancreas transplant is high. Islet transplantation has held promise for over 25 years, but candidates for endocrine replacement therapy must honestly be told the difference in success rates, which are currently much higher with the pancreas.

Donor-specific portal blood transfusion in intestinal transplantation: a prospective, preclinical large animal study

BACKGROUND

Unlike in kidney and heart transplantation, the role of pretransplant donor-specific blood transfusion (DST) has not been studied prospectively in a large animal model of bowel transplantation. We investigated the impact of portal versus systemic DST on overall survival, rejection, graft-versus-host disease (GVHD), and infection after total (small and large) bowel transplantation in pigs.

METHODS

Mixed lymphocyte culture-reactive, outbred pigs underwent total enterectomy and orthotopic total bowel transplantation with portal vein graft drainage. One unit of donor blood was transfused via the portal or systemic circulation (according to a randomization protocol) before graft implantation was begun. We studied six groups, all of which underwent at least a total bowel transplant: group 1 (n=5) comprised nonimmunosuppressed control pigs with portal DST; group 2 (n=6), nonimmunosuppressed control pigs with systemic DST; group 3 (n=5), cyclosporine (CsA)-treated pigs with portal DST; group 4 (n=5), CsA-treated pigs with systemic DST; group 5 (n=5), tacrolimus-treated pigs with portal DST; and group 6 (n=5), tacrolimus-treated pigs with systemic DST. All immunosuppressed pigs received prednisone (2 mg/kg/day) and either CsA (to maintain levels between 250 and 350 ng/ml) or tacrolimus (to maintain levels between 10 and 30 ng/ml). Stomal biopsies and autopsies were obtained to study the incidence of rejection, GVHD, and infection.

RESULTS

Portal DST and tacrolimus-based immunosuppression resulted in the highest survival rates. At 7, 14, and 28 days after transplantation, survival rates in group 5 were 100%, 100%, and 80%; in group 6, 100%, 60%, and 40%; and in group 3, 100%, 0%, and 0%, respectively. Only the combination of portal DST and tacrolimus prevented the occurrence of, and death from, rejection. Death from rejection at 7, 14, and 28 days in group 5 was 0%, 0%, and 0%; in group 6, 0%, 33%, and 67%; and in group 3, 0%, 100%, and 100%, respectively. Of note, if immunosuppression was used, the groups with portal (versus systemic) DST had a higher risk of death from infection but a lower risk of death from GVHD. Simultaneous immunologic events were noted more frequently in groups with systemic (versus portal) DST. Long-term survival was noted only in groups with tacrolimus-based immunosuppression and was more common for those with portal (versus systemic) DST.

CONCLUSIONS

Portal DST at the time of total bowel transplantation and posttransplant immunosuppression with tacrolimus prevent rejection and significantly increase graft survival. The combination of portal antigen presentation and tacrolimus needs to be studied in clinical bowel transplantation.

Pregnancy after pancreas transplantation in the cyclosporine era: report from the International Pancreas Transplant Registry

BACKGROUND

As of December 31, 1996, a total of 9012 pancreas transplants have been reported to the International Pancreas Transplant Registry (IPTR). Over 75% of these recipients were < or = 40 years of age at the time of their transplant. With continued improvement in short- and long-term outcome after transplant, an increasing number of female recipients have become pregnant. However, outcome after pregnancy in pancreas transplant recipients has not been studied in detail.

METHODS

To evaluate the risks of pregnancy after pancreas transplantation in the cyclosporine era, we surveyed the institutions reporting to the IPTR.

RESULTS

Nineteen cases of pregnancy in 17 female recipients of simultaneous pancreas-kidney transplants resulted in 19 live births. Metabolic control during pregnancy was good in all cases. Mean duration of gestation was 35.2-2.2 weeks. Mean birth weight was 2150+/-680 g. Two congenital malformations were reported (one bilateral cataract and one double aortic arch). One child developed type I diabetes at age 3 years. Only one pancreas graft and one kidney graft were lost (in two different recipients). The pancreas graft was lost after delivery (because of acute rejection). The kidney graft was lost 3 months after delivery (impaired function due to previous amphotericin B treatment). One case of a worsened secondary complication (retinopathy) was reported. One recipient died of myocardial infarction 7 years after transplant and 5 years after delivery, in spite of a normal pretransplant coronary angiogram and good pancreas function.

CONCLUSION

This study shows that simultaneous pancreas-kidney transplantation can restore fertility in uremic type I diabetic female recipients. Thus, both posttransplant contraception and fertility counseling are options for female recipients. However, our analysis demonstrates that, when discussing the possibility of pregnancy with female pancreas recipients, these potential risks must be considered: (1) graft loss, (2) progressive maternal morbidity and mortality even with good glycemic control, and (3) diabetes transmission to offspring.

Diagnosis of pancreas rejection: cystoscopic transduodenal versus percutaneous computed tomography scan-guided biopsy

BACKGROUND

The most common cause of graft failure after technically successful pancreas transplants is rejection. Laboratory parameters for detecting pancreas graft rejection are not consistently reliable and can lead to unnecessary antirejection treatment. Histopathologic evaluation is the gold standard in the differential diagnosis of pancreas graft dysfunction. Four biopsy techniques have been described: cystoscopic transduodenal (CB), percutaneous computed tomography scan-guided (PB), open, and laparoscopic biopsy.

METHODS

We studied the two most common techniques, CB and PB, in pancreas transplant recipients with presumed rejection. Group 1 comprised 103 attempts at CB in 82 recipients (53 men, 29 women) with bladder-drained (BD) pancreas transplants, at 1 to 80 (median, 14) months after transplant. Group 2 comprised 93 attempts at PB in 68 recipients (41 men, 27 women), at 0.5 to 64 (median, 14) months after transplant.

RESULTS

In group 1, of 103 attempts at CB, adequate tissue was obtained in 90 (87%): pancreas alone in 23 (22%), pancreas + duodenum in 35 (34%), duodenum alone in 32 (31%). Of the 58 pancreas biopsies, 23 (40%) showed acute rejection. Of the 67 duodenal biopsies, 16 (24%) showed acute rejection. Complications of CB included macrohematuria in 4 recipients (4%) and microhematuria in 32 (31%). We noted no biopsy-related pancreatitis. The mean cost of CB was $2561+/-246. In group 2, of 93 attempts at PB, adequate tissue (all pancreas) was obtained in 67 (72%); of these, 29 (43%) showed acute rejection. Of 23 inaccessible pancreases, 9 (39%) underwent CB; pancreatic tissue was obtained in four (45%), and results were consistent with rejection in all four. Complications of PB included biopsy-related pancreatitis (serum amylase > or = 25%) in five (7%) recipients, macrohematuria in one (1%), and abdominal hemorrhage in two (3%). The mean cost of PB was $1038+/-78. (1) CB and PB prevented unnecessary antirejection treatment in 44% of our recipients with successful biopsies; (2) CB had a higher success rate for obtaining tissue (including duodenal specimens) and a lower rate of major complications; (3) PB was easier and cheaper, did not require general anesthesia, and was performed as an outpatient procedure.

CONCLUSIONS

We conclude that PB should become the biopsy technique of choice in recipients with presumed pancreas graft rejection. If PB fails, recipients with bladder-drained pancreas transplants should undergo CB. If CB fails, or in recipients with enteric-drained or duct-injected pancreas transplants, a laparoscopic or open biopsy should be considered.

Surgical complications requiring early relaparotomy after pancreas transplantation: a multivariate risk factor and economic impact analysis of the cyclosporine era

OBJECTIVES

To study significant surgical complications requiring early (< or = 3 months posttransplant) relaparotomy (relap) after pancreas transplants, and to develop clinically relevant surgical and peritransplant decision-making guidelines for preventing and managing such complications.

SUMMARY BACKGROUND DATA

Pancreas grafts are still associated with the highest surgical complication rate of all routinely transplanted solid organs. However, the impact of surgical complications on morbidity, hospital costs, and graft and patient survival rates has not been analyzed in detail to date.

METHODS

We retrospectively studied surgical complications requiring relap in 441 consecutive cadaver, bladder-drained pancreas transplants (54% simultaneous pancreas and kidney [SPK]; 22% pancreas after kidney [PAK]; 24% pancreas transplant alone [PTA]; 37% retransplant). Outcome and hospital charges were analyzed separately for recipients with versus without reoperation.

RESULTS

The overall relap rate was 32% (SPK, 36%; PAK, 25%; PTA, 16%; p = 0.04). The most common causes were intraabdominal infection and graft pancreatitis (38%), pancreas graft thrombosis (27%), and anastomotic leak (15%). Perioperative relap mortality was 9%; transplant pancreatectomy was necessary in 57% of all recipients with one or more relaps. The pancreas graft was lost in 80% of recipients with versus 41% without relap (p < 0.0001). Patient survival rates were significantly lower (p < 0.05) for recipients with versus without relap. By multivariate analysis, significant risk factors for graft loss included older donor age (SPK, PAK), retransplant (PAK), relap for infection (SPK, PAK), and relap for leak or bleeding (PAK). For death, risk factors included older recipient age (SPK, PAK),retransplant (SPK, PAK), relap for thrombosis (PAK), relap for infection or leak (SPK), and relap for bleeding (PTA).

CONCLUSIONS

Posttransplant surgical complications requiring relap were frequent, resulted in a high rate of pancreas (SPK, PAK, PTA) and kidney (SPK, PAK) graft loss, and had a major economic impact (p = 0.0001). Complications were associated with substantial perioperative mortality and decreased patient survival rates. The focus must therefore shift from graft salvage to preservation of the recipient's life once a pancreas graft-related complication requiring relap occurs. Thus, the threshold for pancreatectomy should be low. In this context, acceptance of older donors and recipients must be reconsidered.

Solitary pancreas transplantation for nonuremic patients with labile insulin-dependent diabetes mellitus

BACKGROUND

Simultaneous pancreas-kidney transplantation has become a widely accepted treatment option for selected uremic patients with insulin-dependent diabetes mellitus (IDDM). Patient survival rates at 1 year exceed 90%, and rates of pancreas graft survival, 70%. However, solitary pancreas transplantation for nonuremic patients with IDDM has been controversial because of the less favorable outcome and the need for long-term immunosuppression with its associated morbidity and mortality.

METHODS

We studied the outcome of 225 solitary pancreas transplants during three immunosuppressive eras: the precyclosporine (CsA) era (n=83), the CsA era (n=118), and the tacrolimus era (n=24). Only patients with labile IDDM (e.g., hypoglycemic unawareness, insulin reactions, > or = 2 failed attempts at intensified insulin therapy for metabolic control) underwent solitary pancreas transplantation. Using univariate and multivariate analyses, we looked at patient and graft survival, the risk of surgical complications, and native kidney function during these three eras.

RESULTS

Pancreas graft survival improved significantly over time: 34% at 1 year after transplantation in the pre-CsA era, 52% in the CsA era, and 80% in the tacrolimus era (P=0.002). Pancreas graft loss due to rejection decreased from 50% at 1 year in the pre-CsA era, to 34% in the CsA era, to 9% in the tacrolimus era (P=0.008). The rate of technical failures (i.e., the risk of surgical complications) decreased from 30% in the pre-CsA era, to 14% in the CsA era, to 0% in the tacrolimus era (P=0.001). Patient survival rates at 1 year have ranged between 88% and 95% in the three eras (P=NS). Matching for at least one antigen on each HLA locus and avoiding HLA-B mismatches significantly decreased the incidence of rejection. The incidence of native kidney failure due to drug-induced toxicity decreased significantly over time, in part because only recipients with pretransplant creatinine clearance > or = 80 ml/min received transplants.

CONCLUSIONS

Solitary pancreas transplantation has become a viable alternative for nonuremic patients with labile IDDM. The risks of surgical complications and drug-induced nephrotoxicity have significantly decreased over time. Using tacrolimus as the mainstay immunosuppressant, patient and graft survival rates now no longer trail those of simultaneous pancreas-kidney transplantation.