Obesity and urologic complications after renal transplantation

Surgical Complications Following Renal Transplantation in a Large Institutional Cohort

Background

Successful renal transplantation (RTx) relies on immunosuppression and an optimal surgical course with few surgical complications. Studies reporting the postoperative complications after RTx are heterogeneous and often lack systematic reporting of complications. This study aims to describe and identify postoperative short-term and long-term complications after RTx in a large institutional cohort and identify risk factors for a complicated surgical course.

Methods

The study is a retrospective single-center cohort of 571 recipients who underwent living or deceased donor open RTx between 2014 and 2021. Data were collected on background information and perioperative and postoperative data. Complications were defined as short-term (<30 d) or long-term (>30 d) after transplantation and graded according to the Clavien-Dindo classification. Multivariable logistic regression was performed to evaluate risk factors for serious short-term complications and multivariable time-dependent Cox regression to evaluate risk factors for long-term complications.

Results

A total of 351 patients received a graft from a deceased donor, and 144 of these grafts were on perfusion machine before transplantation. One or more short-term complications occurred in 345 (60%) patients. Previous RTx was associated with short-term Clavien-Dindo >2 complications in recipients (odds ratio = 2.08; 95% confidence interval [CI], 1.18-3.69; P = 0.01). Being underweight (body mass index <18.5) in combination with increasing age increased the odds of short-term Clavien-Dindo >2 and vascular complications. Increasing blood loss per 100 mL was associated with increased odds of short-term Clavien-Dindo >2 (odds ratio = 1.11; 95% CI, 1.01-1.21; P = 0.032). No associations were found for long-term complications after RTx. The 5-y cumulative incidence of graft loss was 12.6% (95% CI, 8.9-16.3).

Conclusions

Short-term complications are common after RTx, and risk factors for severe short-term complications include previous RTx, increasing age, and low body mass index. No risk factors were identified for severe long-term complications. Further studies should explore whether new surgical techniques can reduce surgical complications in RTx.

Effect of Recipient Body Mass Index on Kidney Transplantation Outcomes: A Systematic Review and Meta-analysis by the Transplant Committee from the French Association of Urology

CONTEXT

The impact of recipient obesity on kidney transplantation (KT) outcomes remains unclear.

OBJECTIVE

The aim of this study was to perform a systematic review and meta-analysis to appraise all available evidence on the outcomes of KT in obese patients (body mass index [BMI] ≥30 kg/m2) versus nonobese patients (BMI <30 kg/m2).

EVIDENCE ACQUISITION

A systematic review and meta-analysis was performed. Search was conducted in the MEDLINE OvidSP, Web of Science, Google Scholar, Embase, and Cochrane databases to identify all studies reporting the outcomes of KT in obese versus nonobese recipients.

EVIDENCE SYNTHESIS

Fifty-two articles met the inclusion criteria. Delayed graft function and surgical complications were significantly higher in obese recipients (delayed graft function: relative risk [RR]: 1.44, 95% confidence interval [CI]: 1.32-1.57, p < 0.01; surgical complications: RR: 1.74, 95% CI: 1.36-2.22, p < 0.0001). Five-year patient survival (RR: 0.96, 95% CI: 0.92-1.00, p = 0.01), 10-yr patient survival (RR: 0.90, 95% CI: 0.84-0.97, p = 0.006), and 10-yr graft survival (RR: 0.87, 95% CI: 0.79-0.96, p = 0.01) were significantly inferior in the obese group.

CONCLUSIONS

KT in obese recipients was associated with lower patient and graft survival, and higher delayed graft function, acute rejection, and medical and surgical complications than nonobese recipients. In the current situation of organ shortage and increasing prevalence of obesity, ways to optimize KT in this setting should be investigated.

PATIENT SUMMARY

Compared with nonobese population, kidney transplantation in obese recipients has inferior patient and graft survival, and higher medical and surgical complications.

Clinical Outcomes in Living Donor Kidney Transplantation: A Single Center Experience in Latin America

BACKGROUND

In Latin America, few reports are available about the clinical outcomes of living donor kidney transplants (LDKT). We aim to evaluate the main clinical outcomes for LDKT patients in a single center's experience.

METHODS

We retrospectively evaluated 530 LDKT patients who underwent transplantation from August 2008 to December 2020 at Colombiana de Trasplantes. Graft survival censored for death and patient survival were determined up to 5 years post-transplantation by the Kaplan-Meier method. Vascular and urinary complications, readmission, and reintervention rates were documented.

RESULTS

A total of 530 LDKT patients were analyzed. Most of the recipients were men (56%). There were 123 patients (23.2%) with a preemptive transplant. Panel reactive antibody type I and II had higher immunologic risk (>20%) in 15.9% of the patients. The donor mean age was 37.8 ± 11.5 years. Most of the donors were women (52.6%) and related to the recipient (69.1%). Multivariate analysis identified panel reactive antibody type II (P = 0.003), female donor (P = 0.001), surgical reintervention at 30 days post-transplantation (P < .01), and delayed graft function (P < .01) as risk factors for graft loss. The graft survival death-censored rates were 93.7% and 89% at 1 and 5 years, respectively. Patient survival rates were 97.0% and 94.1% at 1 and 5 years after transplantation, respectively.

CONCLUSIONS

The long-term graft and patient survival rates in our center are comparable to previous reports from other leading centers. The clinical outcomes from a medium-sized center can be noteworthy, although not entirely new.

Factors Influencing Lymphocele Development After Kidney Transplant: Single Center Experience

OBJECTIVES

Lymphocele is a well-known postoperative surgical complication after kidney transplant. In this study, our aim was to analyze incidence, risk factors, and outcomes of posttransplant lymphocele in a large cohort.

MATERIALS AND METHODS

This observational study included 395 consecutive patients (219 males and 176 females) who underwent kidney transplant procedures from 183 living and 212 deceased donors in our center between January 2007 and 2014. A lymphocele was diagnosed with ultrasonography.

RESULTS

The incidence of lymphoceles in our cohort was 31.9% (n = 126). There were no significant dif-ferences with regard to body mass indexes, age of donors, deceased donor ratios, acute rejection episodes, and history of abdominal surgery between those with and without lymphoceles. The pre-transplant serum albumin levels (3.29 ± 0.67 vs 3.48 ± 0.69 g/dL; P = .009) in the lymphocele group and diabetes mellitus ratios (15.9% vs 4.5%; P < .001) in the nonlymphocele group were lower than levels shown in the other group. The lymphocele ratio in patients who received cyclosporine was higher than that shown in patients who did not received it (37.5% vs. 27.4%; P = .032). There was no difference in lymphocele incidence between patients who were taking and those who were not taking mammalian target of rapamycin inhibitors, mycophenolate mofetil, or mycophenolate sodium. In regression analysis, presence of diabetes mellitus, transplant from deceased donors, older age of donors, and lower albumin levels were independent risk factors for posttransplant lymphocele occurrence.

CONCLUSIONS

Posttransplant lymphocele was a relatively common surgical complication in our cohort. We concluded that diabetes mellitus, use of kidneys from deceased donors, older donor age, and hypoalbuminemia were independent risk factors for lymphocele development.

Nonlinear relationship between body mass index and clinical outcomes after kidney transplantation: A dose-response meta-analysis of 50 observational studies

BACKGROUND

Exact dose-response relationship between body mass index at transplantation and clinical outcomes after kidney transplantation remained unclear, and no specific body mass index threshold and pretransplant weight loss aim were recommended for kidney transplantation candidates among transplant centers.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were searched for literature published up to December 31, 2019. The two-stage, random effect meta-analysis was performed to estimate the dose-response relationship between body mass index and clinical outcomes after kidney transplantation.

RESULTS

Ninety-four studies were included for qualitative assessment and 50 for dose-response meta-analyses. There was a U-shaped relationship between graft loss, patient death, and body mass index. Body mass index with the lowest risk of graft loss was 25.2 kg/m², and preferred body mass index range was 22-28 kg/m². Referring to a body mass index of 22 kg/m², the risk of graft loss was 1.088, 0.981, 1.003, and 1.685 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. Body mass index with the lowest risk of patient death was 24.7 kg/m², and preferred body mass index range was 22-27 kg/m². Referring to a body mass index of 22 kg/m², the patient death risk was 1.115, 0.981, 1.032, and 2.634 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. J-shaped relationships were observed between body mass index and acute rejection, delayed graft function, primary graft nonfunction, and de novo diabetes. Pair-wise comparisons showed that higher body mass index was also a risk factor for cardiovascular diseases, hypertension, infection, longer length of hospital stay, and lower estimated glomerular filtration rate level.

CONCLUSION

Underweight and severe obesity at transplantation are associated with a significantly increased risk of graft loss and patient death. A target body mass index at kidney transplantation is 22-27 kg/m².

Clinical outcome of kidney transplantation after bariatric surgery: A single-center, retrospective cohort study

Patients with class II and III obesity and end‐stage renal disease are often ineligible for kidney transplantation (KTx) due to increased postoperative complications and technically challenging surgery. Bariatric surgery (BS) can be an effective solution for KTx candidates who are considered inoperable. The aim of this study is to evaluate outcomes of KTx after BS and to compare the outcomes to obese recipients (BMI ≥ 35 kg/m²) without BS. This retrospective, single‐center study included patients who received KTx after BS between January 1994 and December 2018. The primary outcome was postoperative complications. The secondary outcomes were graft and patient survival. In total, 156 patients were included, of whom 23 underwent BS prior to KTx. There were no significant differences in postoperative complications. After a median follow‐up of 5.1 years, death‐censored graft survival, uncensored graft survival, and patient survival were similar to controls (log rank test p = .845, .659, and .704, respectively). Dialysis pre‐transplantation (Hazard Ratio (HR) 2.55; 95%CI 1.03–6.34, p = .043) and diabetes (HR 2.41; 95%CI 1.11–5.22, p = .027) were independent risk factors for all‐cause mortality. A kidney from a deceased donor was an independent risk factor for death‐censored graft loss (HR 1.98; 95%CI 1.04–3.79, p = .038). Patients who received a KTx after BS have similar outcomes as obese transplant recipients.

Early Postoperative Complications and Outcomes of Kidney Transplantation in Moderately Obese Patients

BACKGROUND

Obese renal transplant recipients (body mass index [BMI] ≥30 kg/m²) are at risk of delayed graft function and postoperative complications, such as infections or delayed wound healing. There is also a tendency to exclude extremely obese patients from transplantation (KTx). Nonetheless, no association between obesity and increased mortality has been reported. The aim of this study is to evaluate the effect of BMI on the most common surgical and infectious complications after KTx.

MATERIALS AND METHODS

An observational study in 872 patients transplanted from 2010-2017 was conducted. Median BMI was 24.6 (13.9-34.3), and 8.3% of the group was obese. Patient records were searched for early postoperative complications: lymphocele or hematoma (>33 mL), urinary leakage, or urinary tract infection (UTI). Mann-Whitney U and χ² or Fisher exact tests were used. P < .05 was considered statistically significant. The study complies with the Helsinki Congress and the Istanbul Declaration.

RESULTS

Renal primary nonfunction was observed in 1.4% (12/872) of patients. Surgical or infectious complications occurred in 52.7% (453/860) of patients. No correlation between BMI and complication rate was noted. Complications were observed in 56.9% (41/72) of obese vs 52.3% (412/788) of nonobese patients (P = .448), including lymphocele in 15.3% vs 16.4% (P = .810), hematoma in 22.2% vs 19.2% (P = .530), urinary leakage in 1.4% vs 4.6% (P = .203), and UTI in 31.9% vs 32.9% (P = .873), respectively.

CONCLUSIONS

Recipient's BMI has no significant association with the most common surgical complications after KTx. There is no need to delay KTx in moderately obese patients.

Consensus on definition and severity grading of lymphatic complications after kidney transplantation

BACKGROUND

The incidence of lymphatic complications after kidney transplantation varies considerably in the literature. This is partly because a universally accepted definition has not been established. This study aimed to propose an acceptable definition and severity grading system for lymphatic complications based on their management strategy.

METHODS

Relevant literature published in MEDLINE and Web of Science was searched systematically. A consensus for definition and a severity grading was then sought between 20 high-volume transplant centres.

RESULTS

Lymphorrhoea/lymphocele was defined in 32 of 87 included studies. Sixty-three articles explained how lymphatic complications were managed, but none graded their severity. The proposed definition of lymphorrhoea was leakage of more than 50 ml fluid (not urine, blood or pus) per day from the drain, or the drain site after removal of the drain, for more than 1 week after kidney transplantation. The proposed definition of lymphocele was a fluid collection of any size near to the transplanted kidney, after urinoma, haematoma and abscess have been excluded. Grade A lymphatic complications have a minor and/or non-invasive impact on the clinical management of the patient; grade B complications require non-surgical intervention; and grade C complications require invasive surgical intervention.

CONCLUSION

A clear definition and severity grading for lymphatic complications after kidney transplantation was agreed. The proposed definitions should allow better comparisons between studies.

Efficacy and Safety of Intra-gastric Balloon Placement in Dialyzed Patients Awaiting Kidney Transplantation

BACKGROUND

The number of obese patients who are candidates for renal transplantation has considerably increased, but obesity can be a barrier to kidney transplantation. Weight loss is often difficult through diet alone. We studied the efficacy and tolerance of the intra-gastric balloon (IGB) procedure in obese patients who were undergoing dialysis and were candidates for a renal transplantation.

PATIENTS AND METHODS

Obese patients (BMI > 30 kg/m²) who were candidates for renal transplantation were prospectively included in the study between 2010 and 2012. The balloon was inserted and removed during a gastric endoscopy under general anesthesia. The treatment lasted 6 months. The end point was a decrease in BMI after 6 months. Body impedance spectrometry (BIS) and nutritional statute were evaluated initially and then after IGB removal.

RESULTS

Seventeen patients (nine females and eight males) with a mean age of 53.4 years [19.4-69.4] were included. The decrease in body mass index (BMI) during the 6-month placement was 3 kg/m² (from 37.7 to 34.4 kg/m²). The mean weight loss was 7 kg. The mean percentage of excess weight loss after 6 months was 20.2 (± 11.4). The tolerance was good without any complications. Eleven patients underwent kidney transplantation.

CONCLUSION

IGB in obese dialyzed patients who are candidates for renal transplantation is safe and effective. However, the amount of weight loss can vary.

Successful salvage of allograft dysfunction triggered by transplant renal vein thrombosis immediately after kidney transplantation: a case report

Background

Transplant renal vein thrombosis (TRVT) is a severe vascular complication and is caused by various factors, including recipient factors, donor factors, immunosuppression regimens, and surgical techniques. Despite adequate interventions, including thrombolytic therapy or surgical thrombectomy, successful salvage of the allograft is often difficult. We observed a case of TRVT induced by compression of the renal vein immediately after intraoperative abdominal closure.

Case presentation

A 41-year-old male underwent ABO-compatible living kidney transplantation. The donor was his 45-year-old sister, and her right kidney was donated. The allograft had a single artery and vein. One of the preoperative recipient problems was obesity (body mass index, 33.4 kg/m²). Intraoperative Doppler ultrasonography (US) revealed sufficient blood flow throughout the allograft, and urine output was also observed. After surgery, hematuria was observed; the urine output decreased and serum creatinine levels increased to 7.0 mg/dL. Doppler US showed a decrease in diastolic flow and an elevated resistive index, which were similar findings to those noted in acute rejection. Although steroid pulse therapy was initiated, allograft dysfunction was worsening. On postoperative day 4, surgical exploration revealed TRVT; consequently, thrombectomy was performed. The urine output increased, and serum creatinine levels decreased to 1.8 mg/dL. The cause of TRVT development may be that the transplant renal vein was relatively short, due to the right kidney being compressed by surrounding tissues after abdominal closure, and that TRVT was gradually developing due to stagnant blood flow.

Conclusion

Although TRVT is induced by multiple factors, an accurate diagnosis is often difficult. Understanding these factors, including obesity, and considering TRVT as a cause of allograft dysfunction are important during the pre-, peri-, and postoperative periods. Knowledge of TRVT can lead to early and accurate diagnosis and intervention, resulting in better outcomes for the patients with allograft dysfunction.

The Incidence and Pathophysiology of the Obesity Paradox: Should Peritoneal Dialysis and Kidney Transplant Be Offered to Patients with Obesity and End-Stage Renal Disease?

PURPOSE OF REVIEW

To educate nephrologists and primary-care physicians about the incidence, pathophysiology, and survival benefits of the obesity paradox in end-stage renal disease (ESRD). This review also discusses the future of kidney transplant and peritoneal dialysis in obese dialysis patients.

RECENT FINDINGS

Obesity paradox in ESRD was first reported three decades ago, and since then, there have been several epidemiological studies that confirmed the phenomenon. Regardless of the anthropometric indices used to define obesity in ESRD patients, these markers serve to predict the dialysis patient's survival. The pathophysiology of obesity paradox tends to be multifactorial. Recent cohort studies demonstrated a survival benefit in all race and ethnic groups, but Hispanics and blacks experienced increased survival rates when compared to non-Hispanic whites. Obese dialysis patients should be offered peritoneal dialysis, especially if they are new to dialysis and have an adequate renal residual function. Several studies have shown that the benefit of receiving kidney transplant in obese patients exceeds the risks. The robotic-assisted kidney transplant (RAKT) procedure is the latest innovation that could offer hope for obese dialysis patients who have been denied or are waiting for kidney transplant. The obesity paradox phenomenon in ESRD is a unique illustration of survival benefit in a population that has a high overall annual mortality. Peritoneal dialysis should be encouraged for obese patients who have preserved residual renal function. Kidney transplant centers should encourage RAKT utilization in obese dialysis patients instead of denying them a kidney transplant.

Absence of the Effect of Pretransplant Body Mass Index on Post Kidney Transplant Outcomes

CONTEXT

Obesity has been reported as risk factor for reduced posttransplant graft and patient survival and increased delayed graft function (DGF).

OBJECTIVE

The purpose of this work is to analyze the effect of body mass index (BMI) on defined transplant outcomes in patients transplanted under defined guidelines in a kidney transplant program.

DESIGN

Review of a prospectively collected database in renal transplant recipients receiving rabbit antithymocyte globulin induction, mycophenolate mofetil, tacrolimus, and early corticosteroid withdrawal between 2001 and 2011.

SETTING

This review was conducted in a single abdominal transplant program in the United States.

MAIN OUTCOME MEASURES

Primary outcome was death-censored graft survival categorized by posttransplant body mass groups. Secondary outcomes included DGF as well as patient survival.

RESULTS

Four hundred sixty seven patients were identified. No difference was observed in graft survival or DGF between BMI groups. One-year, death-censored graft survival and patient survival rates ranged from 97.5% to 100% and 96.6% to 100%, respectively. Delayed graft function was uncommon across all BMI groups, ranging from 5.3% to 9.1%, with the lowest incidence in patients with a BMI ≥ 35 kg/m(2). Biopsy-proven acute rejection rates at 1 year were similar across all groups (10.1%-14%) as were estimated glomerular filtration rates were at 1, 3, and 5 years.

CONCLUSION

Our results do not show an effect of BMI on posttransplant outcomes, suggesting that relaxation of BMI criteria may be warranted for recipient selection.

Kidney transplantation in obese patients

The World Health Organization estimated that in 2014, over 600 million people met criteria for obesity. In 2011, over 30% of individuals undergoing kidney transplant had a body mass index (BMI) 35 kg/m² or greater. A number of recent studies have confirmed the relationship between overweight/obesity and important comorbidities in kidney transplant patients. As with non-transplant surgeries, the rate of wound and soft tissue complications are increased following transplant as is the incidence of delayed graft function. These two issues appear to contribute to longer length of stay compared to normal BMI. New onset diabetes after transplant and cardiac outcomes also appear to be increased in the obese population. The impact of obesity on patient survival after kidney transplantation remains controversial, but appears to mirror the impact of extremes of BMI in non-transplant populations. Early experience with (open and laparoscopic) Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy support excellent weight loss (in the range of 50%-60% excess weight lost at 1 year), but experts have recommended the need for further studies. Long term nutrient deficiencies remain a concern but in general, these procedures do not appear to adversely impact absorption of immunosuppressive medications. In this study, we review the literature to arrive at a better understanding of the risks related to renal transplantation among individuals with obesity.

Body mass index: short- and long-term impact on kidney transplantation

AIM

The topic of pretransplantation body mass index (BMI) is still a matter of controversy. The aim of this study was to investigate the influence of pretransplant BMI on short- and long-term outcomes in patients receiving kidney transplant.

METHODS

We have analysed 521 renal transplant recipients (RTRs). BMI was categorised as follows: less than or equal to 20, more than 20 to less than or equal to 25, more than 25 to less than or equal to 30 and more than 30 RESULTS: The distribution of the RTRs per category of BMI at baseline was: ≤ 20 (14.4%), > 20 to ≤ 25 (50.9%), > 25 ≤ 30 (26.9%) and > 30 (7.9%). In further analysis, the patients were stratified into four groups according to their pretransplant BMI values. There was no difference in the rates of delayed graft function between the four analysed groups of patients. Recipients with normal pre-transplant BMI were less likely to develop wound complications in comparison to the recipients with high BMI (p = 0.04) and obese recipients (p = 0.0001). RTRs with normal BMI were less likely to develop lymphoceles in comparison to the recipients with high BMI (p = 0.0003). Obese patients were more likely to develop lymphocele in comparison to the recipients with high BMI (p = 0.01). Obese recipients had a longer mean length of hospital stay in comparison to the recipients with normal BMI (p = 0.04). There was no significant difference regarding 1-year graft and patient survival, as well as because of acute rejection crisis between the investigated groups of recipients. We did not find any significant difference in 5-year patients and graft survival between those RTRs with BMI > 20 to ≤ 25 and to those recipients with BMI > 25.

CONCLUSION

Overweight and obese transplant candidates should not be excluded from kidney transplantation.

The combined effect of age and body mass index on outcomes in foregut surgery: a regression model analysis of the National Surgical Quality Improvement Program data

BACKGROUND

In a parallel demographic phenomenon, the elderly and obese populations will become a larger part of our population and surgical practices. The elderly obese surgical risk profile is not clearly defined, although studies have confirmed their independent negative effect on surgical outcomes. Benign foregut surgery is a relatively common complex procedure performed on this demographic and warrants deeper investigation into outcomes. We investigate the synergistic effect of age and body mass index (BMI) on the outcomes of benign foregut surgery.

METHODS

Data from National Surgical Quality Improvement Program were collected for all patients undergoing foregut surgery from 2005 to 2012. Subjects were over 18 years of age and 16 BMI. Primary and secondary outcomes were 30-day mortality and overall 30-day morbidity, respectfully. Binary logistic regression models were used to assess independent and interactive effects of age and BMI.

RESULTS

A total of 19,547 patients had an average age and BMI of 57 and 29.7, respectively. Sample 30-day mortality was 0.32 %. Every 10-year age increase led to a 46 % increased odds of mortality. BMI showed a bimodal distribution with underweight and morbidly obese patients having increased mortality. The effect of BMI only became apparent with increasing age.

CONCLUSIONS

Both age and BMI are independent predictors of mortality; only older patients experienced the bimodal BMI effect. Therefore, increasing age and BMI have a synergistic effect on outcomes after foregut operations.