Comparison of postoperative estimated glomerular filtration rate between kidney donors and radical nephrectomy patients, and risk factors for postoperative chronic kidney disease

Predicting new-baseline glomerular filtration rate (NBGFR) after donor nephrectomy: validation of a split renal function (SRF)-based formula

BACKGROUND

Accurate prediction of post-donor nephrectomy (DN) glomerular filtration rate is potentially useful for evaluating and counselling living kidney donors. Currently, there are limited tools to evaluate post-operative new-baseline glomerular filtration rate (NBGFR) in kidney donors. We aim to validate a conceptually simple formula based on split renal function (SRF) previously developed for radical nephrectomy patients.

METHODS

Eighty-three consecutive patients who underwent DN from 2010 to 2016 were included. Pre-operative CT imaging and functional data including pre-DN baseline Global GFR (108.2 ± 13.2 mL/min/1.73m2) were included. Observed NBGFR was defined as the latest eGFR 3-12 months post-DN. SRF, defined as volume of the contralateral non-resected kidney normalised by total volume of kidneys, was determined from pre-operative cross-sectional imaging (49.2 ± 2.36%). The equation derived from Rathi et al. is as detailed: Predicted NBGFR = 1.24 × (Global GFR Pre-DN) x (SRF).

RESULTS

The relationship between predicted NBGFR (66.0 ± 8.29 mL/min/1.73m2) and observed NBGFR (74.9 ± 16.4 mL/min/1.73m2) was assessed by evaluating correlation coefficients, bias, precision, accuracy, and concordance. The new SRF-based formula for NBGFR prediction correlated strongly with observed post-operative NBGFR (Pearson's r = 0.729) demonstrating minimal bias (median difference = 7.190 mL/min/1.73m2) with good accuracy (96.4% within ± 30%, 62.7% within ± 15%) and precision (IQR of bias =  - 0.094 to 16.227).

CONCLUSION

The SRF-based formula was also able to accurately discriminate all but one patient to an NBGFR of > 45 mL/min/1.73m2. We utilised the newly developed SRF-based formula for predicting NBGFR in a living kidney donor population. Counselling of donor post-operative renal outcomes may then be optimised pre-operatively.

[Renal functional compensation after unilateral radical nephrectomy of renal cell carcinoma]

OBJECTIVE

To investigate factors influencing renal functional compensation(RFC) of the preserved kidney after radical nephrectomy (RN).

METHODS

A total of 286 patients treated with RN in Peking University People's Hospital were retrospectively analyzed. Preoperative body mass index (BMI), systolic blood pressure (SBP), history of smoking, history of chronic diseases and other basic information, as well as preoperative blood biochemistry, urine routine, imaging examination results were recorded. All the patients underwent ^99mtechnetium-diethylenetriamine pentaacetic acid (^99mTc-DTPA) renal scans before operation. The surgical method, pathology and blood creatinine values from 1 month to 60 months after RN were recorded. Preoperative and postoperative estimated glomerular filtration rate (eGFR) was calculated by the chronic kidney disease epidemiology collaboration (CKD-EPI) formula. Renal functional compensation was defined as percent change in eGFR of the preserved kidney after RN compared with the preoperative eGFR. Univariate and multivariate regression analyses were used to identify predictive factors of RFC.

RESULTS

Median age was 61 years and 65.4% of the patients were male. Early stage (T1 or T2) tumors were found in 83.6% of the cases. 18.5% of the patients had preoperative diabetes mellitus, 39.5% had hypertension, 19.2% had a history of smoking, and 27.6% were found to have renal cyst on the contralateral side. In the study, 226 cases underwent laparoscopic radical nephrectomy and 60 cases underwent open radical nephrectomy. Renal clear cell carcinoma was the most common pathological type, accounting for 88.5%. The median tumor maximum diameter was 4.5 cm (0.7-13.5 cm). Median renal function compensation was 27% one month after radical nephrectomy. Functional stability was then observed to 5 years. The results of univariate analysis showed that age, gender, preoperative blood uric acid, preoperative urine protein, contralateral renal cyst, and percentage of split renal function of contralateral kidney were correlated with RFC (P < 0.05). Among them, UA level and split renal function of contralateral kidney were strongly negatively correlated with RFC. The results of multivariate linear regression analysis showed age (P < 0.001), blood uric acid (P < 0.001), urine protein (P=0.002), preoperative eGFR (P < 0.001) and the split renal function of contralateral kidney (P < 0.001) were independent predictors of RFC.

CONCLUSION

The basic examinations, such as blood biochemistry, urine routine and renal scan before RN are of great significance in predicting the compen-satory ability of the preserved kidney after RN, which is supposed to be taken into consideration when making clinical decision.

Early estimated glomerular filtration rate and depression in kidney transplantation recipients: a longitudinal study

Depression is a common psychological problem in kidney transplantation (KT) recipients and affects long-term graft outcomes. Estimated glomerular filtration rate (eGFR) as a commonly used indicator of renal function plays a vital role in follow-up detection after KT. The aim of this study is to observe the change of early eGFR within 3 months after KT and to explore the correlation between eGFR and depression before and after transplantation. The Self-rating Depression Scale was used to evaluate depression. Among 135 patients with KT, 128 patients completed the longitudinal study. We used a one-way repeated-measures analysis of variance to analyze eGFR and a generalized estimating equation model to examine the relationship between depression and eGFR in KT recipients with pre-transplant and 30, 60, 90 days post-transplant. The mean eGFR of KT recipients at four time-points was 5.97 ± 4.83, 72.84 ± 26.06, 79.06 ± 26.45 and 81.79 ± 25.62, respectively. The results demonstrated that eGFR kept steady at 60 days and 90 days post-transplant; depression was significantly associated with eGFR. Earlier identification and treatment of depression in KT recipients may be essential to promote their recovery of early renal function.

Organ-sparing procedures in GU cancer: part 1-organ-sparing procedures in renal and adrenal tumors: a systematic review

PURPOSE

Organ-sparing surgery (OSS) for the kidney and adrenals has emerged as the need for preservation of function is paramount in patients with poor functional reserve. As reports increasingly showed that oncological outcomes were equivalent to radical excision, elective OSS became a viable alternative in patients with otherwise normal reserve. In this review, we summarize the current knowledge of OSS for adrenal and renal tumors.

MATERIALS AND METHODS

PubMed, Web of Science and Cochrane Library Central Search were searched for recently published articles up to December 2017. The following keywords were used; "partial adrenalectomy", "adrenal sparing", "partial nephrectomy", "nephron sparing", "kidney/renal cancer".

RESULTS

Partial adrenalectomy became an attractive alternative to total adrenalectomy avoiding adrenal insufficiency. Both minimally invasive surgery and ablative techniques were increasingly reported for adrenal OSS with adequate residual adrenal function and excellent oncological outcome. Radical nephrectomy remained for many years as the gold standard of treatment for organ-confined renal cell carcinoma. As the need to reduce the impact on renal function, more conservative approaches were utilized. Soon, the non-inferiority of nephron-sparing surgery to that of radical excision became evident and elective partial nephrectomy was gaining ground as the standard of care for small renal masses in patients with normal contralateral kidneys.

CONCLUSIONS

Herein, we present a comprehensive review of the current status of OSS in renal and adrenal tumors.

Outcome Measures Used to Report Kidney Function in Studies Investigating Surgical Management of Kidney Tumours: A Systematic Review

CONTEXT

Most practice decisions relevant to preserving kidney function in patients managed surgically for kidney tumours are driven by observational studies. A wide range of outcome measures are used in these studies, which reduces comparability and increases the risk of reporting bias.

OBJECTIVE

To comprehensively and succinctly describe the outcomes used to evaluate kidney function in studies evaluating surgical management of kidney tumours.

EVIDENCE ACQUISITION

Electronic search of the PubMed database was conducted to identify studies with at least one measure of kidney function in patients managed surgically for kidney tumours, published between January 2000 and September 2017. Abstracts were initially screened for eligibility. Full texts of articles were then evaluated in more detail for inclusion. A narrative synthesis of the evidence was conducted.

EVIDENCE SYNTHESIS

A total of 312 studies, involving 127905 participants, were included in this review. Most were retrospective (n=274) studies and conducted in a single centre (n=264). Overall, 78 unique outcome measures were identified, which were grouped into six outcome categories. Absolute postoperative kidney function (n=187), relative kidney function (n=181), and postoperative chronic kidney disease (n=131) were most frequently reported. Kidney function was predominantly quantified using estimated glomerular filtration rate or creatinine clearance (n=255), most using the modification of diet in renal disease equation (n=182). Only 70 studies provided rationale for specific outcome measures used.

CONCLUSIONS

There is significant variability in the reporting and quantification of kidney function in studies evaluating patients managed surgically for kidney tumours. A standardised approach to measuring and reporting kidney function will increase the effectiveness of outcomes reported and improve relevance of research findings within a clinical context.

PATIENT SUMMARY

Although we know that the removal of a kidney can reduce kidney function, clinical significance of various approaches is a matter of debate. This article demonstrates significant variability in the way kidney function was reported across all studies of patients with kidney cancer undergoing surgery, indicating a need for standardisation.

Influence of CT-based depth correction of renal scintigraphy in evaluation of living kidney donors on side selection and postoperative renal function: is it necessary to know the relative renal function?

PURPOSE

To analyse the influence of CT-based depth correction in the assessment of split renal function in potential living kidney donors.

METHODS

In 116 consecutive living kidney donors preoperative split renal function was assessed using the CT-based depth correction. Influence on donor side selection and postoperative renal function of the living kidney donors were analyzed. Linear regression analysis was performed to identify predictors of postoperative renal function.

RESULTS

A left versus right kidney depth variation of more than 1 cm was found in 40/114 donors (35%). 11 patients (10%) had a difference of more than 5% in relative renal function after depth correction. Kidney depth variation and changes in relative renal function after depth correction would have had influence on side selection in 30 of 114 living kidney donors. CT depth correction did not improve the predictability of postoperative renal function of the living kidney donor. In general, it was not possible to predict the postoperative renal function from preoperative total and relative renal function. In multivariate linear regression analysis, age and BMI were identified as most important predictors for postoperative renal function of the living kidney donors.

CONCLUSIONS

Our results clearly indicate that concerning the postoperative renal function of living kidney donors, the relative renal function of the donated kidney seems to be less important than other factors. A multimodal assessment with consideration of all available results including kidney size, location of the kidney and split renal function remains necessary.

The Effect of Patient and Surgical Characteristics on Renal Function After Partial Nephrectomy

BACKGROUND

The purpose of the study was to identify patient and disease characteristics that have an adverse effect on renal function after partial nephrectomy.

PATIENTS AND METHODS

We conducted a retrospective review of 387 patients who underwent partial nephrectomy for renal tumors between 2006 and 2014. A line plot with a locally weighted scatterplot smoothing was generated to visually assess renal function over time. Univariable and multivariable longitudinal regression analyses incorporated a random intercept and slope to evaluate the association between patient and disease characteristics with renal function after surgery.

RESULTS

Median age was 60 years and most patients were male (255 patients [65.9%]) and white (343 patients [88.6%]). In univariable analysis, advanced age at surgery, larger tumor size, male sex, longer ischemia time, history of smoking, and hypertension were significantly associated with lower preoperative estimated glomerular filtration rate (eGFR). In multivariable analysis, independent predictors of reduced renal function after surgery included advanced age, lower preoperative eGFR, and longer ischemia time. Length of time from surgery was strongly associated with improvement in renal function among all patients.

CONCLUSION

Independent predictors of postoperative decline in renal function include advanced age, lower preoperative eGFR, and longer ischemia time. A substantial number of subjects had recovery in renal function over time after surgery, which continued past the 12-month mark. These findings suggest that patients who undergo partial nephrectomy can experience long-term improvement in renal function. This improvement is most pronounced among younger patients with higher preoperative eGFR.

The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) Study: Protocol for a Prospective Observational Study

Background:

Tumour nephrectomy conveys a significant risk of adverse renal functional outcomes postoperatively, however there are limited strategies for predicting patients at increased risk of these outcomes. The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) study is a prospective observational study evaluating the risk of chronic kidney disease and end-stage kidney disease in tumour nephrectomy patients.

Methods:

The CKD-TUNED study involves analysis of clinical data and collection of tissue, urine and blood samples for the purposes of forming a tissue repository resource for future investigation. Recruitment began in 2013 and is expected to continue until 2023, with a projected sample size between 700-1000 subjects.

Results:

All relevant ethics and site-specific approvals have been granted and all relevant infrastructure is in place. Study methods are undergoing validation and refinement. As of June 2017 there are 267 participants enrolled in the study.

Conclusion:

It is anticipated that this study will have the potential to identify risk factors for adverse renal functional outcomes following tumour nephrectomy, which can be used in the development of predictive models with clinical utility, and in turn improve patient outcomes.

Real Renal Function After Renal Autotransplantation Through the Analysis of Solitary Kidney Autotransplantation Cases

INTRODUCTION

Previous studies of the safety of renal autotransplantation (RAT) have been limited by a lack of evidence. Because of the influence of the opposite kidney, it is difficult to evaluate actual renal function. This study evaluated the actual results of RAT by collecting only cases involving a solitary kidney.

METHODS

Between September 1, 1999, and November 30, 2015, 9 RAT procedures were performed in 9 patients with a solitary kidney. We retrospectively evaluated medical data collected prospectively. Renal function was evaluated using the creatinine level and the estimated glomerular filtration rate (eGFR).

RESULTS

The indications for RAT differed among the nin9e study patients. Five patients had complex renovascular problems, 2 were treated for partial nephrectomy, 1 was had a radically resected ureter due to ureteral cancer, 1 patient underwent RAT for the preservation of renal function during suprarenal-type abdominal aortic aneurysm repair. The mean cold ischemic time was 116.66 minutes (range, 21-256), and the mean follow-up duration was 54.2 months (range, 1 to 184). There were no significant decreases in eGFR until 12 months except 1 patient who underwent RAT with partial nephrectomy due to renal cell cancer.

CONCLUSIONS

We report stable renal function after RAT in patients with solitary kidney. Postoperative complications were rare. This is evidence for the safety of RAT.