Second renal transplantations. Ethical issues clarified by outcome; outcome enhanced by a reliable crossmatch

Differences between kidney retransplant recipients as identified by machine learning consensus clustering

BACKGROUND

Our study aimed to characterize kidney retransplant recipients using an unsupervised machine-learning approach.

METHODS

We performed consensus cluster analysis based on the recipient-, donor-, and transplant-related characteristics in 17 443 kidney retransplant recipients in the OPTN/UNOS database from 2010 to 2019. We identified each cluster's key characteristics using the standardized mean difference of >.3. We compared the posttransplant outcomes, including death-censored graft failure and patient death among the assigned clusters RESULTS: Consensus cluster analysis identified three distinct clusters of kidney retransplant recipients. Cluster 1 recipients were predominantly white and were less sensitized. They were most likely to receive a living donor kidney transplant and more likely to be preemptive (30%) or need ≤1 year of dialysis (32%). In contrast, cluster 2 recipients were the most sensitized (median PRA 95%). They were more likely to have been on dialysis >1 year, and receive a nationally allocated, low HLA mismatch, standard KDPI deceased donor kidney. Recipients in cluster 3 were more likely to be minorities (37% Black; 15% Hispanic). They were moderately sensitized with a median PRA of 87% and were also most likely to have been on dialysis >1 year. They received locally allocated high HLA mismatch kidneys from standard KDPI deceased donors. Thymoglobulin was the most commonly used induction agent for all three clusters. Cluster 1 had the most favorable patient and graft survival, while cluster 3 had the worst patient and graft survival.

CONCLUSION

The use of an unsupervised machine learning approach characterized kidney retransplant recipients into three clinically distinct clusters with differing posttransplant outcomes. Recipients with moderate allosensitization, such as those represented in cluster 3, are perhaps more disadvantaged in the kidney retransplantation process. Potential opportunities for improvement specific to these re-transplant recipients include working to improve opportunities to improve access to living donor kidney transplantation, living donor paired exchange and identifying strategies for better HLA matching.

The risk factors for treatment-related mortality within first three months after kidney transplantation

Mortality at an early stage after kidney transplantation is a disastrous event. Treatment-related mortality (TRM) within 1 or 3 months after kidney transplantation has been rarely reported. We designed a cohort study using the national Korean Network for Organ Sharing database that includes information about kidney recipients between 2002 and 2016. Their demographic, and laboratory data were collected to analyze risk factors of TRM. A total of 19,815 patients who underwent kidney transplantation in any of 40 medical centers were included. The mortality rates 1 month (early TRM) and 3 months (TRM) after transplantation were 1.7% (n = 330) and 4.1% (n = 803), respectively. Based on a multivariate analysis, older age (hazard ratio [HR] = 1.044), deceased donor (HR = 2.210), re-transplantation (HR = 1.675), ABO incompatibility (HR = 1.811), higher glucose (HR = 1.002), and lower albumin (HR = 0.678) were the risk factors for early TRM. Older age (HR = 1.014), deceased donor (HR = 1.642), and hyperglycemia (HR = 1.003) were the common independent risk factors for TRM. In contrast, higher serum glutamic oxaloacetic transaminase (HR = 1.010) was associated with TRM only. The identified risk factors should be considered in patient counselling, and management to prevent TRM. The recipients assigned as the high-risk group require intensive management including glycemic control at the initial stage after transplant.

Graft and patient survival outcomes of a third kidney transplant

BACKGROUND

The waiting time for deceased donor renal transplantation in the United States continues to grow. Retransplant candidates make up a small but growing percentage of the overall transplant waiting list and raise questions about the stewardship of scarce resources. The utility of renal transplantation among individuals with two prior renal transplants is not described in the literature, and we thus sought to determine the survival benefit associated with a third kidney transplant (3KT).

METHODS

Multivariable Cox regression models were created to determine characteristics associated with 3KT outcomes and the survival benefit of 3KT among recipients wait listed and transplanted within the United States between 1995 and 2009.

RESULTS

A total of 4,334 patients were waitlisted for a 3KT and 2,492 patients received a 3KT. In a multivariate analysis, 3KT demonstrated an overall patient survival benefit compared to the waitlist (hazards ratio, 0.379; 95% confidence interval, 0.302-0.475; P<0.001) for those awaiting their first, second, or third kidney transplants, although an inferior graft outcome compared to first kidney transplants. The time to survival benefit did not accrue until 8 months after transplantation. In addition, we found that the duration of second graft survival was predictive of third graft survival, such that second graft survival beyond 5 years is associated with superior 3KT graft survival. Second graft loss in 30 days or less was not associated with inferior 3KT graft survival.

CONCLUSION

A 3KT achieves a survival benefit over remaining on the waitlist, although is associated with inferior graft outcomes compared to first kidney transplants. Graft survival of the second transplant beyond 5 years is associated with superior 3KT graft survival.

[Renal retransplantation: risk factors and results]

OBJECTIVE

to review our experience in renal retransplantations.

MATERIALS AND METHODS

we carried out a retrospective study on 71 patients with retransplantation performed between 1980 and 2005. We studied: the characteristics of the recipient and graft, surgery data, causes of loss of the graft, number of rejects and transplantectomies and, survival of the graft.

RESULTS

the most frequent cause of graft loss was chronic rejection. The causes of first graft loss were not associated with a greater loss of the second graft (p>0.05). The percentage of anti-HLA antibodies increased in the second transplant in comparison to the first (17.23±27.91% vs. 1.21±7.43%) (p=0.001), however, it was not correlated with a significant increase in loss of the second graft (p=0.320). There were no significant differences between the complications of the first and second transplants (p>0.05) and they were not associated with graft loss (p>0.05). The patients with a transplantectomy in the first transplant presented a risk 8.5 times higher of undergoing a second one (p=0.0001; OR: 8.54; CI: 95% 0.941 - 77.501). The most frequent cause of transplantectomies in the second transplant was acute rejection. Acute rejection as a cause for transplantectomy in the first transplant proved to be an independent risk factor of transplantectomy of the second transplant (p=0.009). The mean survival of the second graft was 5.08±4.81 years, higher than the first transplant (p=0.133). The survival of the graft at 1.5 and 10 years was 83%, 75% and 52%, respectively.

CONCLUSIONS

the survival of the second transplant was not lower than the first, neither was there an increase in the number of complications.

Repeat renal allografts treated with sirolimus, cyclosporine, anti-thymocyte globulin induction and continuous steroids achieve similar immunosuppressive efficacy as primary transplants

OBJECTIVE

We sought to examine repeat versus primary renal transplantations using sirolimus-based regimens.

METHODS

We compared 98 repeat versus 200 matched primary recipients treated de novo with sirolimus plus cyclosporine. Every repeat case received polyclonal antibody induction and continuous steroids. Outcomes were evaluated over a mean five-year follow-up by univariate and multivariate techniques. Kaplan-Meier plots were analyzed with using log-rank statistics with significance at P < or = 0.05.

RESULTS

Significant differences in demographic features included greater panel reactive antibody (PRA), younger age, fewer HLA-mismatches and more pre-emptive repeat versus primary grafts. Neither graft and patient survivals, nor incidences of biopsy-proven acute rejection (BPAR), chronic vasculopathy or tubular atrophy/interstitial fibrosis among biopsies performed for cause were significantly different at 1 and 5 years. Younger recipients, better HLA matches and absence of diabetes promoted repeat graft survival; whereas older age, longer cold ischemia time and BPAR reduced primary transplant outcomes. Renal function was similar at 1, 3, 12, 24, 48 and 60 months.

CONCLUSION

At 5 years this sirolimus regimen achieved similar efficacy for repeat versus primary transplantations.

Influence of number of retransplants on renal graft outcome

BACKGROUND

To assess the influence of number of transplants on the renal graft outcome.

METHODS

Retrospective analysis of various factors that could influence the outcome of kidney retransplantation in patients receiving more than one allograft between 1993 and 2005 at our center.

RESULTS

During the 12-year period (1993-2005), 196 patients received more than one renal transplant. Of these, 163 had two (group 1) and 33 had more than two transplants (group II). In group II, 24 patients had three, eight had four, and one had five consecutive allografts. The control group comprised of 100 randomly selected patients receiving a first graft during the same period. In group I, 53 (32.5%) grafts failed. Eighteen (11.0%) patients died with functioning grafts. In group II, 14 (41.2%) grafts failed while four patients (11.8%) died with functioning grafts. In group I, actuarial graft survival rates at 1, 2, 3, and 4 years were 82.3%, 67.3%, 55.97%, and 42.14%, respectively. In group II, the respective figures were 84.85%, 66.67%, 60.61%, and 51.52%. The difference was not statistically significant (P = .96). In the control group, 1-, 2-, 3-, and 4-year survival rates were 92%, 84, 74%, and 60%, respectively. The difference between the control and study groups was statistically significant (P = .0002).

CONCLUSION

Graft survival after retransplantation is relatively inferior when compared to the primary graft but still remains fairly high. Therefore, previous graft failure should not be considered as a relative contraindication for retransplantation.

Second and Third Kidney Transplantations

We reviewed the results of second and third kidney transplantations at our center. Among 1500 patients who had undergone kidney transplantation from 1968 to October 2005, we discovered 77 (male 55 and female 22 of overall mean age = 48.9 years) second transplantations and 5 (male 4, female 1; mean age = 46.8 years) third transplantations. The 82 kidneys were derived from living donors in 67 patients and from cadaveric donors in 15 patients. The mean duration from the first to the second transplantation was 89 months, and from the second to the third transplantation, 32.7 months. Among the second and third transplantations and graft nephrectomies, we failed to observe additional surgical complications compared with first transplants and over 80% graft survival at 1 year.

Anti-HLA alloantibodies in pediatric solid organ transplantation

An increasing number of studies demonstrate the clinical impact of preformed and de novo anti-human leucocyte antigen alloantibody (HLA-Ab) in solid organ transplantation (Tx). The screening of HLA-Ab in candidates and transplant recipients has evolved over time, with continuous improvement in the sensitivity and specificity of assays for HLA-Ab detection. Furthermore, histologic markers of complement activation pathways are currently implemented in the diagnosis of antibody-mediated rejection (AMR). Therapeutic strategies, including depletion of HLA-Ab and B cells, have allowed Tx across antibody barriers, or have rescued patients with AMR. The purpose of the present review is to summarize the state-of-the-art of HLA-Ab detection, clinical significance and therapeutic strategies in pediatric solid organ Tx.

Kidney retransplantation in comparison with first kidney transplantation

INTRODUCTION

The aim of this study was to depict the outcome of second and third kidney allografts in comparison with first kidney allografts.

METHODS

Among 2150 kidney transplantations are 103 second and 5 third transplantations. Demographic characteristics and survivals of retransplanted patients were compared with a randomly selected group of first kidney recipients, consisting of two cases matched with each retransplanted patient for age, gender, and date of transplantation.

RESULTS

Retransplanted patients consisted of 78 men and 30 women of mean age 32.63 +/- 11.92 years. They had received kidneys from 91 living-unrelated and 17 living-related donors. Median followup was 27 months. One-, 2-, 3-, and 5-year graft survivals were 81.4%, 78.9%, 78.9%, and 73.7% among retransplants, versus 92.9%, 91.5%, 89.8%, and 85.3% in the control group, respectively (P = .0037). Patient survival was 96%, 94.6%, 92.4%, and 87.8% in the retransplant group versus 93.1%, 92.4%, 90.9%, 87.4% in the control group, respectively (P = .63). Also, graft survivals were slightly lower in female compared to male retransplant patients (P = .09). No significant difference in survival rates was seen in different age groups.

CONCLUSION

It seems that kidney retransplantation can yield desirable outcomes, albeit relatively lower graft survivals.

Living-donor kidney retransplantation: risk factors and outcome

OBJECTIVE

To review the results of kidney retransplantation at our centre.

PATIENTS AND METHODS

Between March 1976 and January 2002, 1406 kidneys were transplanted; among these, 54 patients received a second graft (39 men, mean age 32.1 years, sd 8.6). The donors were 48 relatives (mean age 35.4 years, sd 10.1).

RESULTS

The mean (sd, range) duration of the first graft was 49.1 (45.9, 1-192) months and the main cause of these grafts failing was immunological. The mean duration of graft failure was 17.3 (10.5, 5-62) months. The rate of histocompatibility leukocyte antigen (HLA)-A, -B >3 was 16.7% and of haplotype DR matching was 11%. The immunosuppression regimen was mainly based on cyclosporin (75%). There were 33 episodes of acute rejection in 23 patients. The major complications were hypertension (70%), infections (30%) and hepatitis (11%). The overall graft and patient survival was good; 15 grafts (27%) were lost during the follow-up of 1-17 years. Ten patients died, five with a functioning graft. Multivariate analysis showed that donor relationship, primary immunosuppression, duration of first graft and serum creatinine level at 1 year were predictors of graft survival.

CONCLUSION

Renal retransplantation is the treatment of choice in patients who have lost their graft. The use of related living-donors and potent immunosuppression could help to improve the outcome.

Ten-year survival of second kidney transplants: impact of immunologic factors and renal function at 12 months

BACKGROUND

The aim of the present study was to assess long-term survival of cadaveric second kidney allografts performed in our center and to determine risk factors predictive of long-term graft outcome.

METHODS

Of 1704 kidney transplantations performed between January 1985 and March 1998, 233 were second grafts. The majority of the recipients were sensitized. All patients were treated with the same quadruple immunosuppressive regimen.

RESULTS

Kaplan-Meier analysis documented graft survival of 89% at 1 year, 76% at 5 years, and 53% at 10 years. Graft survival was similar for second and primary kidney transplants performed during the same period of time. When long-term second graft survival was examined, only two risk factors were found to be significant: (1) the degree of human leukocyte antigen (HLA) DR mismatch (MM) and (2) the number of acute rejection episodes. Multivariate analysis of several pre- and posttransplant variables also confirmed the importance of HLA MM (DR> A), but also, identified serum creatinine at 12 months as the most significant predictor of graft survival. In addition, the Cox proportional hazards model revealed that only the year of transplantation had an independent significant effect on acute rejection occurrence (RR = 0.591, 95%CI 0.437 to 0.801, P < 0.0007). Indeed, the incidence of acute rejection was found to decrease over time (44% of patients experienced at least one episode of acute rejection before 1990 vs. 17% after 1990).

CONCLUSION

Finally, second graft long-term outcome shows an improved evolution according to the time period resulting from a strong decrease in acute rejection incidence and the impact of creatinine at 12 months.

Retransplantation of multiple organs: how many organs should one individual receive?

Every year, the transplant waiting list gets longer, while donor numbers essentially remain the same. This makes the responsibility of being good stewards of this precious and limited resource greater than ever. Transplant teams, who are both committed to their patients and aware of this important responsibility, are left to make the difficult and ethical decisions regarding retransplantation. Retransplantation of organs in pediatric patients presents a different set of issues to consider, and the results are promising. This case study presents a boy who received a kidney transplant for focal segmental glomerulosclerosis at age 5. At age 11, because of the recurrence of focal segmental glomerulosclerosis and severe cardiomyopathy, he required a rare combined kidney-heart transplant. At age 17, he developed chronic renal failure and posttransplant coronary artery disease, most likely related to a period of noncompliance, and required yet another combined kidney-heart transplant. He is currently alive and well 2 years after transplantation.

Retransplantation of Multiple Organs: How Many Organs Should One Individual Receive?

Every year, the transplant waiting list gets longer, while donor numbers essentially remain the same. This makes the responsibility of being good stewards of this precious and limited resource greater than ever. Transplant teams, who are both committed to their patients and aware of this important responsibility, are left to make the difficult and ethical decisions regarding retransplantation. Retransplantation of organs in pediatric patients presents a different set of issues to consider, and the results are promising. This case study presents a boy who received a kidney transplant for focal segmental glomerulosclerosis at age 5. At age 11, because of the recurrence of focal segmental glomerulosclerosis and severe cardiomyopathy, he required a rare combined kidney-heart transplant. At age 17, he developed chronic renal failure and posttransplant coronary artery disease, most likely related to a period of noncompliance, and required yet another combined kidney-heart transplant. He is currently alive and well 2 years after transplantation.

Acute humoral rejection in renal allograft recipients: I. Incidence, serology and clinical characteristics

BACKGROUND

Acute rejection (AR) associated with de novo production of donor-specific antibodies (DSA) is a clinicopathological entity that carries a poor prognosis (acute humoral rejection, AHR). The aim of this study was to determine the incidence and clinical characteristics of AHR in renal allograft recipients, and to further analyze the antibodies involved.

METHODS

During a 4-year period, 232 renal transplants (Tx) were performed at our institution. Assays for DSA included T and B cell cytotoxic and/or flow cytometric cross-matches and cytotoxic antibody screens (PRA). C4d complement staining was performed on frozen biopsy tissue.

RESULTS

A total of 81 patients (35%) suffered at least one episode of AR within the first 3 months: 51 had steroid-insensitive AR whereas the remaining 30 had steroid-sensitive AR. No DSA were found in patients with steroid-sensitive AR. In contrast, circulating DSA were found in 19/51 patients (37%) with steroid-insensitive AR, and widespread C4d deposits in peritubular capillaries were present in 18 of these 19 (95%). In at least three cases, antibodies were against donor HLA class II antigens. DSA were not found in the remaining 32 patients but C4d staining was positive in 2 of 32. The DSA/C4d positive (n=18) and DSA/C4d negative (n=30) groups differed in pre-Tx PRA levels, percentage of re-Tx patients, refractoriness to antilymphocyte therapy, and outcome. Plasmapheresis and tacrolimus-mycophenolate mofetil rescue reversed rejection in 9 of 10 recipients with refractory AHR.

CONCLUSION

More than one-third of the patients with steroid-insensitive AR had evidence of AHR, often resistant to antilymphocyte therapy. Most cases (95%) with DSA at the time of rejection had widespread C4d deposits in peritubular capillaries, suggesting a pathogenic role of the circulating alloantibody. Combined DSA testing and C4d staining provides a useful approach for the early diagnosis of AHR, a condition that often necessitates a more intensive therapeutic rescue regimen.

Factors that impact on the outcome of second renal transplants in children

We have reviewed the incidence, demography, and outcome of children who have received a repeat transplant in the North American Pediatric Renal Transplant Cooperative Study registry. From 1987 through 1994, 3290 primary and 573 first repeat transplants were performed on North American children. Living donor grafts were used in 52% of primary and 23% of first repeat transplants. Of primary transplants, 23.7% were among children under the age of 6 years. For repeat transplants, the percentage was 15% for the same category. The percentage of 2-DR mismatches was 27% for primary and 40% for repeat transplants (P < 0.01). Graft survival rates for primary transplants at 6, 12, 24, 36, and 60 months were 88%, 85%, 80%, 76%, and 69%, respectively, compared with 81%, 77%, 71%, 64%, and 52% for repeat transplants at the same time periods (P < 0.05). For cadaver donor source transplants, graft survival rates were 83%, 79%, 74%, 69%, and 62%, compared with 79%, 74%, 68%, 60%, and 47% for the repeat transplants (P < 0.01). However, for living related repeat transplants, the rates of 88%, 86%, 81%, 78%, and 72% were not significantly different from the rates of 93%, 91%, 87%, 83%, and 76% for primary transplants. A proportional hazards model for cadaver donor source repeat transplants evaluated donor age, recipient age, race, use of T-cell induction therapy, number of HLA-DR mismatches, year of transplantation, and cold storage time. Only the use of kidneys from cadaver donors less than 6 years of age was predictive of graft failure. Graft survival rates at 12 and 24 months were 77% and 70%, respectively, for donors > 6 years of age, and 58% and 54% for donors < 6 years of age (P < 0.007). We conclude that avoiding the use of younger aged cadaver donors would assure better graft survival for repeat transplants and negate the ethical dilemma facing the issue of retransplantation.