Objectives: A lack of donors continues to be a significant problem. Kidney donors with a body mass index ≥ 30 kg/m2 are not suitable for laparoscopic donor nephrectomy; however, some studies have suggested that an obese donor could be an appropriate donor with similar surgical outcomes. Here, we report the results of our 10-year experience of laparoscopic donor nephrectomy, examining the effects of body mass index on the surgical results of laparoscopic donor nephrectomy.
Materials and Methods: We retrospectively reviewed medical records of patients who underwent laparoscopic donor nephrectomy at the Shahid Beheshti University Medical Science, Urology Center (Tehran, Iran) from 2005 to 2015. The collected information included pretransplant and posttransplant serum levels of hemoglobin and creatinine. We also collected data on surgical outcomes (operation time, cold and warm ischemia, need for blood transfusion, and conversion to open surgery, length of hospital stay, and complication rates) with respect to body mass index categories (≤ 24.9, 25-29.9, and ≥ 30 kg/m2).
Results: Of 1083 kidney donors, 732 donors had body mass index of ≤ 24.9 kg/m2, 256 had body mass index between 25 and 29.9 kg/m2, and 95 had body mass index of ≥ 30 kg/m2. Differences among groups were not significant in terms of operation time (P = .558), warm or cold ischemic time (P = .829 and .951, respectively), blood transfusion (P = .873), and length of hospital stay (P = .850).
Conclusions: The laparoscopic approach for donor nephrectomy is a safe and effective method in obese donors without significant postoperative complications.
Key words : Kidney donor laparoscopy, Obesity, Renal transplant
Kidney transplant is the treatment of choice for patients with end-stage renal disease and is associated with improved quality of life.1 However, the greatest challenge for kidney transplant continues to be a shortage of living donors, as the demand for kidneys is greater than the available supply.2 The mean wait time is more than 4 years in many countries, even for those patients who are less than 65 years old.3 For older patients on wait lists, about half will die before they receive a kidney transplant.4 The greatest numbers of living donors for kidney transplant have been shown in the United States, Brazil, Iran, Mexico, and Japan.5
Significant factors that affect transplant outcomes are type of kidney transplant (living or deceased donor) and quality of donor kidneys.6,7 Delayed graft function and graft failure are associated with donor age, and donor obesity may contribute to worse posttransplant outcomes; therefore, transplant of kidneys from unrelated young healthy donors is preferred.8,9 In some kidney transplant centers, using strict criteria for living-donor kidney transplant (LDKT) have resulted in a reduction in the number of LDKT procedures.3 Accordingly, some studies have suggested more balanced criteria for LDKT, such as allowing the use of older donors, donors with hypertension, donors with obesity, or donors with reduced glomerular filtration rate and proteinuria and hematuria.10
Obesity, defined as body mass index (BMI) ≥ 30 kg/m2, is an important global pandemic health problem with an increasing trend in incidence.5 Initial guidelines have reported higher rejection rates, perioperative complications, and morbidity and mortality rates in obese kidney donors.6 However, laparoscopic donor nephrectomy (LDN) in healthy obese donors may be associated with favorable surgical outcomes.7-9 In our center, LDN in obese donors has not increased the risk of surgical and preoperative complications. We report our single-center 10-year experience with LDN in obese and nonobese donors.
Materials and Methods
We retrospectively reviewed the medical records of patients who underwent LDN at the Urology Center at the Shahid Beheshti University Medical Science (Tehran, Iran) from 2005 to 2015. The protocol of the study was approved by the Ethics Committee of Shahid Beheshti University Medical Science (ethics code: IR.SBMU.UNRC.REC.1395.7).
Determination of eligibility for LDN was based on the opinion of the nephrologist. Patients ranged in age from 18 to 65 years old and had a glomerular filtration rate value > 80 mL/min. In addition, eligible patients had no systemic diseases, including hypertension, diabetes, proteinuria, history of recurrent renal stones, microscopic hematuria, thrombosis, or thromboemboli. Included patients also had no psychologic contraindications and had no family history of renal disease, diabetes, and hypertension. All included patients had complete medical records. In this study, all patients who met the inclusion criteria were included by applying the convenient sampling method. We used medical records to obtain pretransplant and posttransplant serum levels of hemoglobin and creatinine.
A prophylactic antibiotic (1 g cefazolin) was administered to all kidney donors 30 minutes before surgery. Fellows under the supervision of 2 experienced laparoscopic urologists performed all LDN procedures. A transperitoneal approach was used, and the kidney was removed through a Pfannenstiel incision. Total surgical time, intra- and postoperative blood transfusion amounts, and the need for conversion to open surgery were recorded. Major intraoperative complications were considered as vascular and visceral organ injury, and minor intraoperative complications were considered as arrhythmia, adrenal injury, and ureter cutting. Major postoperative complications were considered as retroperitoneal hematoma, ventricular tachycardia, pulmonary emboli, and spleen injury. Minor postoperative complications included urinary tract infection, ileus, subcutaneous collection, wound infection, atelectasis, retention, hydrocele, thigh weakness, hand numbness, pleural effusion, operation site collection, omentum extrusion, long-term leakage at drain site, thrombocytopenia, increased bilirubin or liver enzyme levels, subcutaneous emphysema, pelvic hematoma, respiratory distress, gastrointestinal bleeding, pneumothorax without chest tube, and bilateral foot edema. The duration of hospital stay and requirements for reoperation or readmission were also recorded. All parameters, including complication rates, were compared among BMI groups.
Collected data were analyzed with the statistical software IBM SPSS Statistics for Windows version 21.0 (IBM Corp., Armonk, NY, USA). Results of quantitative variables are presented as mean ± standard deviation, and results of categorical variables are presented as frequency and percentage. The 1-sample Kolmogorov-Smirnov test was used to investigate the normal distribution of data. Patients were categorized into 3 groups on the basis of their BMI (≤ 24.9, 25-29.9, and ≥ 30 kg/m2). Continuous variables were compared among these 3 groups using 1-way analysis of variance, and chi-square test was used for categorical variables. For all statistical tests, P values < .05 were considered statistically significant.
Our study included 1083 kidney donors with mean age ± standard deviation of 27.7 ± 5.2 years; 80.8% of donors were men and 19.2% were women. Kidney donors were categorized according to BMI as follows: 732 had BMI ≤ 24.9 kg/m2, 256 had BMI between 25 and 29.9 kg/m2, and 95 had BMI ≥ 30 kg/m2. Differences among these groups were not significant in terms of demographics and preoperative serum levels of creatinine and hemoglobin (P > .05) (Table 1).
As shown in Table 2 and Table 3, intraoperative parameters, including operating time, duration of warm and cold ischemia, requirement for blood transfusion, readmission rate, reoperation rate, and hospital length of stay were not significantly different among the 3 BMI groups (P > .05). However, the number of cases of LDN converted to open surgery was different among the 3 groups. Differences in postoperative serum levels of hemoglobin and creatinine were not significant among the 3 BMI groups, and no significant differences were shown among the 3 BMI groups with regard to minor and major intraoperative and postoperative complications (P > .05). Only 1 LDN in the group with BMI of ≤ 25 kg/m2 was converted to open surgery due to vascular injury.
Our results indicated no significant differences in preoperative complications and incidence of poor surgical outcomes in obese versus nonobese healthy donors. Few studies have compared surgical outcomes between obese and nonobese donors. In their investigation of 69 117 living donors in the United States, Schold and associates indicated that obesity increased the length of hospital stay and procedure-related complications (odds ratio = 1.146, 95% confidence interval, 0.87-1.83).11 These results are in contrast with the results of our study, which could be caused by differences in level of obesity. In our study, 4 donors with BMI > 40 kg/m2 were excluded from the study, with obesity only including BMI levels between 30 and 39.9 kg/m2. Guidelines consider BMI > 30 kg/m2 as a relative contraindication to donation, suggesting that BMI is associated with kidney transplant outcomes, with obesity affecting comorbidities posttransplant.12 In our study, the lack of significant differences in surgical outcomes among our 3 BMI groups could be caused by the inclusion of only otherwise healthy donors, with hypertension and diabetes therefore not affecting the results.
About 20% of donors are obese, and including these as kidney donors can increase the donor pool.13 We found no significant differences in surgical outcomes of obese versus nonobese donors. In a study from Heimbach and colleagues, donors undergoing LDN with a BMI ≥ 35 kg/m2 had a similar length of stay, renal function, and microalbuminuria compared with donors undergoing LDN with BMI < 25 kg/m2.7 Another study that compared donors with BMI > 27 kg/m2 versus donors with BMI < 25 kg/m2 undergoing LDN reported no significant differences in the number of complications.14 Although these previous results agree with our present study, the group also reported significantly less blood loss and shorter operation time in obese women compared with men, hypothesizing that this may be due to a technically easier LDN procedure in women.14 Differences in the number of surgical complications, such as blood loss and increased transfusion requirements, between obese versus nonobese donors have been due to the surgical techniques used in early studies, as donors had previously required open nephrectomy.15,16 However, with the introduction of LDN, overall rates of blood loss, analgesic requirements, and duration of hospital stay have substantially decreased.17,18 That is, there is a lack of differences in complication rates between obese versus nonobese donors who had LDN,14 similar to our study. Despite these results, guidelines still suggest that BMI is an absolute contraindication for LDN.19
Kok and associates reported higher conversion rates in obese male donors.14 Although obesity is associated with several renal pathologies,20 in our present study, obese donors did not have higher serum creatinine levels before surgery. However, the kidney weight was increased with increased BMI. These results are consistent with the results of previous research suggesting that obese donors have a larger kidney size.21 Increased kidney weight in obese individuals is attributed to hypertrophy of nephrons, which can also impair tubular and glomerular function or is due to the intracellular and extracellular accumulation of fluid and lipid components.20 A laparoscopic approach for obese kidney donors may be associated with increased warm ischemia time, but this is not considered as a risk factor for delayed graft function.22 However, in our present study, warm ischemic time and the pre- and postoperative serum levels of creatinine were not different among the 3 BMI groups, indicating that similar outcomes can be obtained in the absence of kidney disease and/or other comorbidities.
One of the limitations of our present study was its retrospective nature, which limited proposing the causal relationship between the variables. Furthermore, the results were reported with respect to examinations of medical records; accordingly, any bias in the recorded data could have affected the results of this study.
In our comparison of surgical outcomes among healthy donors with different BMIs undergoing LDN, obesity did not affect the postsurgical outcomes. Not only were the risks of minor and major intra- and postoperative complications similar among the 3 BMI groups, but also postoperative serum creatinine levels, blood loss, and length of hospital stay were also similar. These results suggest that a laparoscopic approach can be considered for obese donors who are otherwise healthy.
DOI : 10.6002/ect.2019.0381
From the 1Department of Urology, Shahid Labbafinejad Hospital, Shahid Beheshti
University of Medical Sciences, and the 2Urology and Nephrology Research Center
(UNRC), Shahid Beheshti University of Medical Sciences, Tehran, Iran
Acknowledgements: The authors have no sources of funding for this study and have no conflicts of interest to declare.
Corresponding author: Mohammad Hadi Radfar, Urology and Nephrology Research Center (UNRC), Shahid Beheshti University of Medical Sciences, Shahid Labbafinejad Hospital, 9th Boostan, Pasdaran Avenue, Tehran, Iran
Phone: +98 21 23602221, +98 912 3877647
Table 1. Comparison of Demographics and Baseline Characteristics of Patients According to Body Mass Index
Table 2. Comparison of Demographics and Baseline Characteristics of Patients According to Body Mass Index
Table 3. Comparison of Major and Minor Intraoperative and Postoperative Complications According to Body Mass Index