Risk Factors for Delayed Renal Graft Function and Their Impact on Renal Transplantation Outcome

Clinical indicators of slow graft function and outcome after pediatric kidney transplantation

BACKGROUND

Lesser degrees of perioperative ischemia-reperfusion injury that does not require dialysis may nonetheless influence allograft outcomes, necessitating evaluation of suitable surrogate indicators of perioperative allograft injury.

METHODS

This retrospective analysis of pediatric kidney transplants evaluated two indicators representing pace and completeness of recovery, for association with 12-month estimated glomerular filtration rate (eGFR) and first-year rate of eGFR decline: time to creatinine nadir (TTN) and ratio of recipient/donor unadjusted GFR (uGFR_R/D ) at 1-month post-transplant. Donor, recipient, and perioperative risk factors were tested further for association with these 2 indicators.

RESULTS

179 patients (190 transplants) aged 13 (IQR 7-17) years and 56% male were included. Twelve-month eGFR was strongly associated with unadjusted GFR at 1 month (uGFR_1M , p < .001) and uGFR_R/D (p = .003), but not with TTN. None of the indicators was associated with the rate of subsequent eGFR decline after 1-month post-transplant. As a potential surrogate indicator, uGFR_1M is effectively modeled by TTN and uGFR_R/D (adjusted R²  = 0.57) and is associated with 12-month eGFR (β = 0.81 ± 0.08; p < .001). Clinical factors associated with uGFR_R/D included donor uGFR (p < .001), BSA (p = .026), age (p = .074), and recipient BSA (p < .001). Factors associated with pace of recovery (TTN) included donor uGFR (p = .018), type (p = .019), and recipient BSA (p = .022).

CONCLUSIONS

The uGFR_R/D ratio, but not TTN, is a useful indicator of perioperative allograft damage that is associated with one-year functional outcome; and uGFR_1M is a potential early surrogate outcome. Donor, recipient, and perioperative factors that are associated with slow allograft function are identified.

Effects of polyethylene glycol-20k IV solution on donor management in a canine model of donor brain death

BACKGROUND

Traditionally, vasopressors and crystalloids have been used to stabilize brain dead donors; however, the use of crystalloid is fraught with complications. This study aimed to investigate the effectiveness of a newly developed impermeant solution, polyethylene glycol-20k IV solution (PEG-20k) for resuscitation and support of brain dead organ donors.

METHODS

Brain death was induced in adult beagle dogs and a set volume of PEG-20k or crystalloid solution was given thereafter. The animals were then resuscitated over 16 h with vasopressors and crystalloid as necessary to maintain mean arterial pressure of 80-100 mmHg. The kidneys were procured and cold-stored for 24 h, after which they were analyzed using the isolated perfused kidney model.

RESULTS

The study group required significantly less crystalloid volume and vasopressors while having less urine output and requiring less potassium supplementation than the control group. Though the two groups' mean arterial pressure and lactate levels were comparable, the study group's kidneys showed less preservation injury after short-term reperfusion indexed by decreased lactate dehydrogenase release and higher creatinine clearance than the control group.

CONCLUSIONS

The use of polyethylene glycol-20k IV solution for resuscitating brain dead donors decreases cell swelling and improves intravascular volume, thereby improving end organ oxygen delivery before procurement and so preventing ischemia-reperfusion injury after transplantation.

Identification of Factors Associated With Acute Tubular Necrosis Following Kidney Transplant in Northern Mexico: Increased Risk With Cold Ischemia After 8 Hours

AIM

To identify potential risk factors associated with the incidence of acute tubular necrosis (ATN) following kidney transplant in a sample of patients from northern Mexico.

METHODS

Secondary analysis of data extracted from clinical files of patients who underwent a kidney transplant between 2000 and 2017 at Christus Muguerza Hospital in the city of Chihuahua. The final sample with complete data included 485 patients. ATN was diagnosed in 13.2% of patients using pathologic, clinical, and laboratory criteria. Adjusted odds ratio (ORs) with 95% CIs from multivariate binary logistic regression were used to identify predictors of ATN.

RESULTS

Only 4 of 21 variables analyzed remained statistically significant in the final adjusted model. Cold and warm ischemia followed time-trend patterns with higher odds with longer ischemia times. For cold ischemia, compared with 0 to 240 minutes, ORs were 1.32 (95% CI, 0.49-3.51) for 241-480 minutes, 4.87 (95% CI, 2.29-10.3) for 481-960 minutes, and 10.0 (95% CI, 2.86-35.0) for > 960 minutes; for warm ischemia, compared with 40 to 59 minutes, these were 6.27 (95% CI, 1.95-20.8) for 60-70 minutes and 10.32 (95% CI, 1.95-54.4) for 71-110 minutes. Hypotension during surgery was associated with a higher chance of ATN (OR, 15.9; 95% CI, 4.97-50.9). When the recipients' age was 30 years or older, the probability also increased significantly (OR, 2.88; 95% CI, 1.09-7.57). The final model fitted well and explained 27% of the probability to develop ATN after a kidney transplant.

CONCLUSION

Shortening the duration of ischemia and avoiding hypotension during surgery is essential to prevent ATN following a kidney transplant.

Analysis of Risk Factors for Allograft Outcome Comparing 2 Kidneys From the Same Donor in Separate Recipients

BACKGROUND

An analysis of 2 kidney transplants from the same donor at the same center enables us to analyze the influence of risk factors on the outcome of the grafts in different recipients.

METHODS

We retrospectively analyzed 88 kidneys from 44 donors that were implanted in 88 recipients at our institution between 2007-2016. We defined unsatisfactory outcome as glomerular filtration rate <30 mL/min/1.73 m² allograft loss or recipient death within the first year after transplantation. Fifty-three kidneys were allocated and age-matched to donors above the age of 65 years (via Eurotransplant Senior Program or center offer). We compared kidney pairs with satisfactory outcome in both recipients (group A) to pairs with divergent outcome (group B) and unsatisfactory outcome in both recipients (group C).

RESULTS

Thirty-four grafts (17 donors) had a satisfactory outcome for both recipients (group A), and 16 grafts (8 donors) had an unsatisfactory outcome for both recipients (group C). Donor age was significantly higher in group C vs group A (67.5 ± 6.7 vs 56.4 ± 16.0 years, P = .010). The 19 donors donating 1 kidney with satisfactory and the other with unsatisfactory outcome were 67.4 ± 10.7 years old (group B). A severe surgical complication occurred more often in recipients with an unsatisfactory outcome in comparison to patients with a satisfactory outcome.

CONCLUSION

Donor age is an important risk factor for an unsatisfactory outcome, either in one or both kidneys of the same donor.

Gene expression profile in delay graft function: inflammatory markers are associated with recipient and donor risk factors

Background. Delayed graft function (DGF) remains an important problem after kidney transplantation and reduced long-term graft survival of the transplanted organ. The aim of the present study was to determine if the development of DGF was associated with a specific pattern of inflammatory gene expression in expanded criteria of deceased donor kidney transplantation. Also, we explored the presence of correlations between DGF risk factors and the profile that was found. Methods. Seven days after kidney transplant, a cDNA microarray was performed on biopsies of graft from patients with and without DGF. Data was confirmed by real-time PCR. Correlations were performed between inflammatory gene expression and clinical risk factors. Results. From a total of 84 genes analyzed, 58 genes were upregulated while only 1 gene was downregulated in patients with DGF compared with no DGF (P = 0.01). The most relevant genes fold changes observed was IFNA1, IL-10, IL-1F7, IL-1R1, HMOX-1, and TGF-β. The results were confirmed for IFNA1, IL-1R1, HMOX-1 and TGF-β. A correlation was observed between TGF-β, donor age, and preablation creatinine, but not body mass index (BMI). Also, TGF-β showed an association with recipient age, while IFNA1 correlated with recipient BMI. Furthermore, TGF-β, IFNA1 and HMOX-1 correlated with several posttransplant kidney function markers, such as diuresis, ultrasound Doppler, and glycemia. Conclusions. Overall, the present study shows that DGF is associated with inflammatory markers, which are correlated with donor and recipient DGF risk factors.

Delayed graft function and long-term outcome in kidney transplantation

BACKGROUND

There are still many controversies about the impact of delayed graft function (DGF) on kidney transplantation outcome. The aims of this study were to define factors associated with DGF and to ascertain the relative impact of DGF on kidney transplantation outcome, both in the early postoperative period and in long-term follow-up.

PATIENTS AND METHODS

Four hundred kidney transplant recipients were reviewed to assess the clinical impact of DGF on long-term outcome.

RESULTS

The overall prevalence of DGF was 24.3%. DGF was significantly associated with increasing recipient and donor age, duration of dialysis, and cold ischemia time. Patients with DGF displayed a significantly worse graft (P = .005) and patient (P < .001) survival compared with recipients with immediate function.

CONCLUSION

DGF is a frequent complication of renal transplantation and may be associated with a reduced graft and even patient survival. Strategies to prevent graft injury and, more specifically, DGF may be an important clue to provide a better long-term outcome in kidney transplantation.

Does timing of post-renal transplant diuresis affect graft survival in live-donor renal transplants?

OBJECTIVE

To study the effect of timing of diuresis on short and long term graft survival in live-donor (LD) renal transplants.

METHODS

Between 1976 and 2005, 1747 consecutive LD renal transplants were performed in a single institution. Patients were classified according to timing of diuresis after vascular de-clamping; group 1 included patients with diuresis within 10 min; group 2 started diuresis between 10 and 60 min after de-clamping; group 3 started diuresis between 1 and 24 h after de-clamping; and group 4 started diuresis > 24 h after de-clamping. Patients' data were stored on an electronic database and were reviewed for risk factors and clinical relevance of timing of diuresis.

RESULTS

Groups 1-4 comprised 1598 (91.5%), 87 (5%), 44 (2.5%) and 18 (1%) patients, respectively. By multivariate analysis, vascular thrombosis was the significant risk factor for delayed diuresis. Delayed diuresis was significantly associated with the occurrence of acute tubular necrosis (ATN), and acute and chronic rejection. Graft and patient survival rates were significantly affected by the timing of diuresis. The 1-year graft survival rates were 93.8, 83.0, 83.6 and 55.6%, and the 5-year graft survival rates were 77.4, 59.4, 69.4 and 35.7% in groups 1, 2, 3 and 4, respectively (P < 0.001). The 1-year patient survival rates were 96.5, 84.4, 90.7 and 61.1% and the 5-year patient survival rates were 87.1, 72.0, 78.1 and 52.4% in groups 1, 2, 3 and 4, respectively (P < 0.001).

CONCLUSION

Delayed diuresis is a rare event after LD renal transplantation, which has an adverse effect on short- and long-term graft and patient survival.

A risk prediction model for delayed graft function in the current era of deceased donor renal transplantation

Delayed graft function (DGF) impacts short- and long-term outcomes. We present a model for predicting DGF after renal transplantation. A multivariable logistic regression analysis of 24,337 deceased donor renal transplant recipients (2003-2006) was performed. We developed a nomogram, depicting relative contribution of risk factors, and a novel web-based calculator (http://www.transplantcalculator.com/DGF) as an easily accessible tool for predicting DGF. Risk factors in the modern era were compared with their relative impact in an earlier era (1995-1998). Although the impact of many risk factors remained similar over time, weight of immunological factors attenuated, while impact of donor renal function increased by 2-fold. This may reflect advances in immunosuppression and increased utilization of kidneys from expanded criteria donors (ECDs) in the modern era. The most significant factors associated with DGF were cold ischemia time, donor creatinine, body mass index, donation after cardiac death and donor age. In addition to predicting DGF, the model predicted graft failure. A 25-50% probability of DGF was associated with a 50% increased risk of graft failure relative to a DGF risk < 25%, whereas a > 50% DGF risk was associated with a 2-fold increased risk of graft failure. This tool is useful for predicting DGF and long-term outcomes at the time of transplant.

Trends in HLA antibody screening and identification and their role in transplantation

HLA testing has been a staple in transplantation since the recognition that antibodies, directed against lymphocytes, were associated with allograft failure. This seminal finding led to the discovery of the MHC and the appreciation of the importance of HLA testing in transplantation. Early approaches focused on the importance of HLA matching, and were an important aspect of deceased organ donor allocation. More recently, and as a direct result of improvements in immunosuppression, there has been a movement away from 'matching' as the driving force in organ allocation. By contrast, we are now challenged with selecting donor-recipient pairs based on acceptable mismatches. For patients devoid of HLA antibodies, this is not an issue. However, for patients with HLA alloantibodies, that is, the sensitized patient, we face significant challenges in assessing the repertoire of the HLA antibody reactivity they possess. Over the past several years, significant advances in HLA antibody detection have occurred. Solid-phase, multiplex testing platforms have replaced traditional cell-based assays, and have provided better sensitivity and specificity in antibody detection. As a direct result of improved antibody identification, many programs are moving into the realm of the 'virtual crossmatch'. The virtual crossmatch has proven to be successful in renal, cardiac and lung transplantation, and has resulted in a greater percentage of sensitized patients gaining access to transplantation. This review will be devoted to highlighting the latest developments in antibody assessments and discussing their utilization in transplant testing.

Pulsatile perfusion of kidney allografts

PURPOSE OF REVIEW

The purpose of this article is to describe the current use of pulsatile kidney perfusion during organ preservation and the effects on kidney allograft outcomes and utilization.

RECENT FINDINGS

As of spring 2008, there were 75 629 candidates on the kidney waiting list in the USA according to United Network for Organ Sharing data. In 2006, a total of 1815 deceased donor expanded criteria donors kidneys were transplanted, and approximately 80% of those kidneys had cold ischemic time of over 12 h. The utilization of kidney pulsatile perfusion varies extensively throughout the USA with rates of 7-12% in our institution.

SUMMARY

Data on the use of pulsatile hypothermic perfusion for kidneys during organ preservation are limited and mostly retrospective. Most authors agree that pulsatile perfusion is safe and leads to a decrease in delayed graft function, especially for marginal kidneys from extended criteria or deceased donors. The long-term effects of delayed graft function on graft survival remain to be seen. With the recent large-sampled international prospective randomized trial recently completed, we may see more kidneys pulsatile perfused. This may lead to an increase in the utilization of otherwise discarded kidneys, though these data are difficult to extrapolate.