Warm Ischemia Time at Vascular Anastomosis is an Independent Predictor for Delayed Graft Function in Kidney Transplant Recipients

Kidney Transplantation Anastomotic Time Is Jointly Associated With Resident and Attending Experience

INTRODUCTION

Few studies evaluate the interplay of attending and resident learning curves in surgical education. Anastomotic time is known to be correlated with transplant outcomes in kidney transplantation. We aimed to evaluate the correlation between the combination of resident and attending experience and anastomotic time in kidney transplantation.

METHODS

We conducted a single-center retrospective cohort study of deceased donor kidney transplants from 2006 to 2019. To analyze the effect of attending and resident experience, dyads were classified as six combinations of early versus later practice attending and resident postgraduate year (PGY-2, PGY-3, and PGY-4/5). Attendings with less than 3 y of postfellowship practice were considered early practice. Linear mixed effects models tested the effects of attending experience, resident PGY, recipient body mass index, and technical operative characteristics (number of donor arteries, operative side) on anastomosis time.

RESULTS

The final linear mixed effects model included 1306 transplants. Compared to later practice attendings with PGY-4/5 residents as reference, early practice attendings paired with PGY-2 or PGY-3 residents had longer anastomotic times (P ≤ 0.005) when adjusted for recipient body mass index, number of donor arteries, and transplant side. When PGY-4/5 residents were paired with early practice attendings, no difference in anastomotic time was demonstrated. When paired with later practice attendings, PGY-2 residents had longer anastomotic times (P < 0.001) while PGY-3 anastomotic times did not differ from PGY-4/5.

CONCLUSIONS

This study demonstrates the correlation between trainee and attending experience jointly and anastomotic time, suggesting that pairing residents and attendings by experience may improve surgical training and potentially patient-related outcomes.

Can robotic gastric bypass be considered a valid alternative to laparoscopy? Our early experience and literature review

Background

Robotic bariatric surgery serves as an alternative to laparoscopy. The technology provides the surgeon with an accurate three-dimensional view, allowing complex maneuvers while maintaining full control of the operating room.

Hypothesis

We report our experience with this innovative surgery compared with laparoscopy during Roux-en-Y gastric bypass to demonstrate its safety and feasibility. The aim of this study is to evaluate potential differences between the robotic and laparoscopic techniques.

Materials and methods

Our study retrospectively identified 153 consecutive obese patients who underwent either laparoscopic or robotic gastric bypass (RGB) procedures over a 2-year period at the Department of Medical and Surgical Sciences, University of Foggia. Data on demographics, operative time, conversion rate, length of hospital stay, and mortality were collected and compared between two groups of patients: 82 patients who underwent laparoscopic procedures and 71 who underwent robotic procedures.

Results

We analyzed 153 patients who underwent gastric bypass with a mean age of 42.58 years, of whom 74 were female; 71 were treated with a robotic approach and 82 with a laparoscopic approach. The mean operative time was 224.75 ± 10.4 min for RGB (including docking time) and 101.22 min for laparoscopic gastric bypass (LGB) (p < 0.05), which is statistically significant. The median length of stay was 4.1 days for the RGB group and 3.9 days for the LGB group (p = 0.89). There is only one conversion to laparoscopy in the RGB group. We observed only one case of postoperative complications, specifically one episode of endoluminal bleeding in the laparoscopic group, which was successfully managed with medical treatment. No mortality was observed in either group.

Conclusion

The statistical analysis shows to support the robotic approach that had a lower incidence of complications but a longer operative duration. Based on our experience, the laparoscopic approach remains a technique with more haptic feedback than the robotic approach, making surgeons feel more confident.This study has been registered on ClinicalTrial.gov Protocol Registration and Results System with this ID: NCT05746936 for the Organization UFoggia (https://clinicaltrials.gov/ct2/show/NCT05746936).

The Kidney Transplant: Maintaining Excellent Outcomes While Increasing Skills Acquisition

OBJECTIVE/BACKGROUND

Kidney transplantation is a complex operation that incorporates multiple fundamental surgical techniques and is an excellent opportunity for surgical skill development during residency training. We hypothesized that increasing resident competency, measured as anastomosis time, could be demonstrated while maintaining high-quality surgical outcomes during the learning process.

METHODS

We performed a retrospective cohort study of surgical resident involvement in kidney transplantation and recorded the anastomosis time. The study population comprised adult, single organ kidney transplants (n = 2052) at a large academic transplant center between 2006 and 2019. Descriptive statistics included frequencies, medians, and means. A mixed model of anastomosis time on number of procedures was fitted. Poisson models were fitted with outcomes of the number of patients with delayed graft function and number of patients that underwent reoperation postoperatively, with the exposure being number of kidney transplants performed by resident.

RESULTS

Results from the mixed model suggest that as the number of times a resident performs the surgery increases, the time to conduct the operation decreases with statistical significance. The Poisson regression demonstrated no significant relationship between the operative volume of a resident and postoperative complications.

CONCLUSION

This study demonstrated statistical evidence that with an increase in the number of renal transplantations performed by a surgical resident, anastomosis time decreased. It also demonstrated no significant relationship between number of kidney transplants performed by a resident and postoperative complications, suggesting that patient outcomes for this operation are not adversely affected by resident involvement.

Mean Warm Ischemia Time among Kidney Transplant Patients in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction

In renal transplantation, warm ischemia time is the interval from the removal of a procured kidney from ice storage to initiating graft reperfusion. Successful kidney transplantation depends on warm ischemia time. The study aims to find the mean warm ischemia time among kidney transplant patients in a tertiary care centre.

Methods

This descriptive cross-sectional study was conducted among kidney transplant patients in a tertiary care centre. Data from 15 December 2012 to 15 October 2022 were collected between 1 December 2022 to 4 January 2023 from the hospital records. Ethical approval was taken from the Nepal Health Research Council (Reference number: 1341). All first-time living-related kidney transplant recipients were included in the study. All the patients undergoing kidney transplants from brain-dead donors were excluded from the study. Convenience sampling method was used. Point estimate and 95% Confidence Interval were calculated.

Results

Among 230 patients, the mean warm ischemia time was 35.45±7.35 min. The mean first warm ischemia time was 4.28±2.05 min and the mean second warm ischemia time was 31.27±7.04 min. The mean age of the recipients was 35.14±10.49 years (range 14-64), of which 173 (75.20%) were male and 57 (24.80%) were female.

Conclusions

The mean warm ischemia time among kidney transplant patients in a tertiary care centre was similar to the studies done in similar settings.

Keywords

kidney transplantation; prevalence; warm ischemia.

Renal transplant anastomotic time-Every minute counts!

The impact of anastomotic time in renal transplant is under recognized and not well studied. It is one of the few controllable factors that affect the incidence of delayed graft function (DGF). Our study aimed at quantifying the impact of anastomotic time. We performed a retrospective review of 424 renal transplants between the years 2006 and 2020. A total of 247 deceased donor renal transplants formed the study cohort. Patients were divided into two groups based on the presence or absence of DGF. Variables with p < 0.3 were analyzed using the binary logistic regression test. The final analysis showed anastomotic time to be significantly associated with DGF with odds ratio of 1.04 per minute corresponding to 4% increase in DGF incidence with every minute increment in anastomotic time. Other variables that had significant impact on DGF were DCD donor (odds ratio - 8.7) and donor terminal creatinine. We concluded that anastomotic time had significant impact on the development of DGF and hence should be minimized.

Insulating jackets thermally protect kidneys in an ex vivo model of second warm ischemia

BACKGROUND

Kidney transplantation is the current optimal treatment for suitable patients with end-stage renal disease. The second warm ischemic time (SWIT) is known to negatively impact delayed graft function, and long-term graft survival, and methods are required to ameliorate the impacts of SWIT on transplantation outcomes.

MATERIALS AND METHODS

This study primarily focused on determining the effect of a novel thermally insulating jacket on the thermal profile of the human kidney and quantifying the reduction in thermal energy experienced using this device (KPJ™). An ex vivo simulated transplantation model was developed to determine the thermal profiles of non-utilized human kidneys with and without KPJ™ (n = 5). Control kidney temperature profiles were validated against the temperature profiles of n = 10 kidneys during clinical kidney transplantation.

RESULTS

Using the ex-vivo water bath model, the thermally insulated human kidney reached the 15°C metabolic threshold temperature at 44.5 ± 1.9 min (vs control: 17.3 ± 1.8 min (p = 0.00172)) and remained within the 18°C threshold until 53.3 ± 1.3 min (vs control: 20.9 ± 2.0 min (p = 0.002)). The specific heat capacity of KPJ™ protected kidney was four-fold compared to the control kidney. The clinical temperature audit, closely correlated with the water bath model, hence validating this ex-vivo human kidney transplant model.

CONCLUSION

Intraoperative thermal protection is a simple and viable method of reducing the thermal injury that occurs during the SWIT and increasing the specific heat capacity of the system. Such technology could easily be translated into clinical kidney transplant practice.

A Proof-of-Concept Preclinical Study Using a Novel Thermal Insulation Device in a Porcine Kidney Auto-Transplantation Model

Ischemia-reperfusion injury remains a fundamental problem during organ transplantation logistics. One key technical factor is the rapid allograft rewarming during the time of vascular reconstruction in the recipient. In this pilot study, a new thermal insulation bag (TIB) for organ transplantation was used. Insulation capacity, tissue compatibility, and usability were tested initially ex vivo on porcine kidneys (n = 24) followed by the first in vivo usage. Fourteen female German landrace pigs underwent kidney auto-transplantation after 24 h cold storage (4 °C). During the implantation process the kidney was either insulated with the new TIB, or it was not thermo-protected at all, which represents the clinical standard. In this proof-of-concept study, the usability (knife-to-skin-time) and the general thermal capacity (30 min warm storage at 38 °C ex vivo p < 0.001) was shown. The clinical outcome showed significant differences in the determination of CRP and pi-GST levels. Syndecan-1 Antibody staining showed clear significant higher counts in the control group (p < 0.01) indicating epithelial damage. However, the effect on renal outcomes in not severely pre-damaged kidneys does not appear to be conclusively significant. A close follow-up study is warranted, especially in the context of marginal organs or in cases where anastomosis-times are prolonged due to surgical complexity (e.g., multiple vessels and complex reconstructions).

Cancer Metabolism and Ischemia-Reperfusion Injury: Two Sides of the Same Coin

Cancer cells are characterized by the reprogramming of certain cell metabolisms via activation of definite pathways and regulation of gene signaling. Ischemia-reperfusion injury (IRI) is characterized by tissue damage and death following a lack of perfusion and oxygenation. It is most commonly seen in the setting of organ transplantation. Interestingly, the microenvironments seen in cancer and ischemic tissues are quite similar, especially due to the hypoxic state that occurs in both. As a consequence, there is genetic signaling involved in response to IRI that has common pathways with cancer. Some of these changes are seen across the board with many cancer cells and are known as Hallmarks of Cancer, among which are aerobic glycolysis and the induction of angiogenesis. This literature review aims to compare the metabolic pathways that are altered in cancer tissues and in normal tissues subjected to IRI in order to find common adaptive processes and to identify key pathways that could represent a therapeutic target in both pathologies. By increasing our understanding of this relationship, clinical correlations can be made and applied practically to improve outcomes of transplanted organs, given the known association with acute rejection, delayed graft function, and poor graft survival. The following metabolic pathways are discussed in our review, both in the setting of cancer and IRI: apoptosis, glycolysis, and angiogenesis. The role of the immune system in both pathologies as well as mitochondrial function and the production of reactive oxygen species (ROS) are reviewed.

Delayed Graft Function Under the Microscope: Surveillance Biopsies in Kidney Transplantation

Delayed graft function (DGF) is a common complication of kidney transplantation and frequently leads to the necessity of surveillance biopsies. The purpose of this study is to describe the histological findings in surveillance biopsies of deceased donor kidney transplant recipients and evaluate the risk factors for graft outcomes. This is a monocentric, retrospective study including kidney transplant recipients that underwent a graft biopsy during the DGF period between January 2006 and July 2019. 356 biopsies were performed in 335 deceased donor transplant recipients. Biopsies were analyzed according to the Banff classification. The main histological findings were: acute tubular necrosis in 150 biopsies (42.1%), acute rejection in 96 biopsies (26.9%), and borderline findings in 91 biopsies (25.5%). In the multivariate analysis, recipient age (p = 0.028) and DGF duration (p = 0.005) were associated with rejection, antibody-induction with anti-thymocyte globulin (ATG) was protective (p = 0.001). The occurrence of rejection was associated with lower death-censored graft survival (log-rank; p = 0.009). Surveillance biopsies of kidney grafts experiencing DGF remain an essential tool for the care of kidney transplant recipients. The recipient’s age and duration of DGF are independent risk factors for acute rejection, while antibody-induction therapy with ATG is associated with protection from its occurrence.

Acute Kidney Injury (AKI) before and after Kidney Transplantation: Causes, Medical Approach, and Implications for the Long-Term Outcomes

Acute kidney injury (AKI) is a common finding in kidney donors and recipients. AKI in kidney donor, which increases the risk of delayed graft function (DGF), may not by itself jeopardize the short- and long-term outcome of transplantation. However, some forms of AKI may induce graft rejection, fibrosis, and eventually graft dysfunction. Therefore, various strategies have been proposed to identify conditions at highest risk of AKI-induced DGF, that can be treated by targeting the donor, the recipient, or even the graft itself with the use of perfusion machines. AKI that occurs early post-transplant after a period of initial recovery of graft function may reflect serious and often occult systemic complications that may require prompt intervention to prevent graft loss. AKI that develops long after transplantation is often related to nephrotoxic drug reactions. In symptomatic patients, AKI is usually associated with various systemic medical complications and could represent a risk of mortality. Electronic systems have been developed to alert transplant physicians that AKI has occurred in a transplant recipient during long-term outpatient follow-up. Herein, we will review most recent understandings of pathophysiology, diagnosis, therapeutic approach, and short- and long-term consequences of AKI occurring in both the donor and in the kidney transplant recipient.

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.

Comparison Between Robotic and Laparoscopic or Open Anastomoses: A Systematic Review and Meta-Analysis

INTRODUCTION

Robotic surgery has been increasingly used in fashioning various surgical anastomoses. Our aim was to collect and analyze outcomes related to anastomoses performed using a robotic approach and compare them with those done using laparoscopic or open approaches through meta-analysis.

METHODS

A systematic review was conducted for articles comparing robotic with laparoscopic and/or open operations (colectomy, low anterior resection, gastrectomy, Roux-en-Y gastric bypass (RYGB), pancreaticoduodenectomy, radical cystectomy, pyeloplasty, radical prostatectomy, renal transplant) published up to June 2019 searching Medline, Scopus, Google Scholar, Clinical Trials and the Cochrane Central Register of Controlled Trials. Studies containing information about outcomes related to hand-sewn anastomoses were included for meta-analysis. Studies with stapled anastomoses or without relevant information about the anastomotic technique were excluded. We also excluded studies in which the anastomoses were performed extracorporeally in laparoscopic or robotic operations.

RESULTS

We included 83 studies referring to the aforementioned operations (4 randomized controlled and 79 non-randomized, 10 prospective and 69 retrospective) apart from colectomy and low anterior resection. Anastomoses done using robotic instruments provided similar results to those done using laparoscopic or open approach in regards to anastomotic leak or stricture. However, there were lower rates of stenosis in robotic than in laparoscopic RYGB (p=0.01) and in robotic than in open radical prostatectomy (p<0.00001). Moreover, all anastomoses needed more time to be performed using the robotic rather than the open approach in renal transplant (p≤0.001).

CONCLUSION

Robotic anastomoses provide equal outcomes with laparoscopic and open ones in most operations, with a few notable exceptions.

Outcomes From Right Versus Left Deceased-Donor Kidney Transplants: A US National Cohort Study

RATIONALE & OBJECTIVE

There may be important transplant-related differences between right and left kidneys, including logistical/surgical considerations about vessel length for the right compared to the left kidney from the same donor. Because US centers choose between the right and left kidney when their recipient is ranked higher on a "match-run," we sought to determine whether deceased-donor right kidneys have had worse posttransplantation outcomes than left kidneys.

STUDY DESIGN

Paired Organ Procurement and Transplantation Network analysis.

SETTING & PARTICIPANTS

Deceased-donor kidney pairs transplanted during 1990 to 2016.

EXPOSURE

Right versus left kidney controlling for other significant factors.

OUTCOMES

Delayed graft function (DGF), all-cause and death-censored graft failure, and mortality.

ANALYTICAL APPROACH

Multivariable conditional logistic regression for DGF; proportional hazards models (conditional on same donor) for failure/mortality with right kidneys (operationalized as 6-month time-varying coefficients) adjusting for DGF and other confounders.

RESULTS

87,112 recipient pairs shared the following donor characteristics: mean age of 41 ± 14 years, 60% males, and 11% with cardiac death. Recipient characteristics were numerically similar by donor kidney side but with some statistical differences given the sample size. Right kidneys had slightly longer cold ischemia time. DGF occurred more often for right kidneys (28% vs 25.8%; P < 0.001; adjusted OR, 1.15 [95% CI, 1.12-1.17]). The adjusted hazard ratio (aHR) for all-cause graft failure with right kidneys within 6 months was 1.07 (95% CI, 1.03-1.11), and was 0.99 (95% CI, 0.97-1.01) thereafter. The aHRs for death-censored graft failure with right kidneys before and after 6 months were 1.11 (95% CI, 1.06-1.16) and 0.96 (95% CI, 0.93-0.99), respectively; the corresonding aHRs for mortality were 0.99 (95% CI, 0.93-1.04) and 1.00 (95% CI, 0.98-1.03), respectively.

LIMITATIONS

Registry data, different transplant eras, reasons for kidney side unavailable.

CONCLUSIONS

There is modest association for transplantation of right kidneys with DGF and graft loss within the first 6 months, which is lost beyond this time point. These findings do not support the use of laterality of deceased-donor kidneys as an important factor in organ acceptance decisions.