The 1-year decline in estimated glomerular filtration rate (eGFR) after radical nephrectomy in patients with renal masses and matched living kidney donors is the same

Unexpected Outcomes of Renal Function after Radical Nephrectomy: Histology Relevance along with Clinical Aspects

Acute kidney injury (AKI) and chronic kidney disease (CKD) are common events after radical nephrectomy (RN). In this study we aimed to predict AKI and CKD after RN relying on specific histological aspects. We collected data from a cohort of 144 patients who underwent radical nephrectomy. A histopathological review of the healthy part of the removed kidney was performed using an established chronicity score (CS). Logistic regression analyses were performed to predict AKI after RN, while linear regression analysis was adopted for estimated glomerular filtration rate (eGFR) variation at 1 year. The outcomes of the study were to determine variables correlated with AKI onset, and with eGFR decay at 1 year. The proportion of AKI was 64%. Logistic analyses showed that baseline eGFR independently predicted AKI (odds ratio 1.04, 95%CI 1.02:1.06). Moreover, AKI (Beta −16, 95%CI −21:−11), baseline eGFR (Beta −0.42, 95%CI −0.52:−0.33), and the presence of arterial narrowing (Beta 10, 95%CI 4:15) were independently associated with eGFR decline. Our findings showed that AKI onset and eGFR decline were more likely to occur with higher baseline eGFR and lower CS, highlighting that RN in normal renal function patients represents a more traumatic event than its CKD counterpart.

Organ-Specific Monitoring of Solitary Kidney after Living Donation by Using Markers of Glomerular Filtration Rate and Urinary Proteins

BACKGROUND

Effective follow-up after living kidney donation is important for maintaining the renal function of the donor. We investigated whether the estimated glomerular filtration rate (eGFR) and urinary protein and enzyme levels can provide important information regarding the state of the remaining kidney after donor nephrectomy.

METHODS

Seventy-five living donations were included (prospective/retrospective) in the study. The following parameters were measured up to 1 year after donor nephrectomy: serum creatinine and cystatin C as markers of the GFR; the high-molecular-weight urinary proteins as markers of glomerular injury; and the low-molecular-weight urinary proteins and urinary enzymes as markers of tubular function.

RESULTS

One year after kidney donation, the creatinine and cystatin C values were 1.38-fold increased than their initial values, while the eGFR was 32% lower. At that time, 38% of donors had a moderate or high risk of CKD progression. The biochemical urinary glomerular and tubular kidney markers examined showed different behaviors. After a transient increase, the glomerular proteins normalized. Conversely, the detection of low-molecular-weight urinary proteins and enzymes reflected mild tubular damage at the end of the study period.

CONCLUSIONS

Our findings suggest that for the evaluation of mild tubular damage, low-molecular-weight marker proteins should be included in the urine diagnostic of a personalized living kidney donor follow-up.

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.

Risk for cancer in living kidney donors and recipients

OBJECTIVE

Malignancy following renal transplantation remains inconsistent with the reported safety of kidney donation during the long-term follow-up.

METHODS

We conducted searches of the published literature which included healthy participants, recipients, living kidney donors (LKDs), and the availability of outcome data for malignancy. Eight from 938 potentially relevant studies were analyzed by means of fixed-effects model or random-effects model, as appropriately.

RESULTS

In 48,950 participants, the follow-up range was 18 months to 20 years, and the mean age of the subjects was approximately 41 years. The incidence rate with 95% confidence interval (CI) for malignancy after kidney transplantation was 0.03 (0.01-0.05) in recipients and 0.03 (0.1-0.07) in LKDs, giving a pooled incidence rate of 0.03 (95% CI 0.02-0.04). LKDs contrasted nondonors by the overall odds ratio and 95% CI for total cancer of 2.80 (2.69-2.92).

CONCLUSIONS

Kidney transplantation was associated with an increased risk of cancer during a long-term follow-up. Long-term risk for cancer in LKDs and kidney recipients should be monitored.

Predictive model of 1-year postoperative renal function after living donor nephrectomy

OBJECTIVE

Kidney transplantation from a living donor nephrectomy (LDN) is the best treatment for end-stage renal disease, but decrease in donor renal function is often revealed. The aim of this study was to evaluate the association between preoperative factors and postoperative estimated glomerular filtration rate (eGFR) and test a predictive model to estimate postoperative eGFR, 1 year after LDN.

PATIENTS AND METHODS

We reviewed 226 records of consecutive patients who underwent laparoscopic live donor nephrectomy between 2006 and 2014 in a single tertiary center. Of these, complete data on 202 patients were analyzed. A training (2/3 of the whole population) and a validation set (1/3) were randomized. A multivariate regression model was used to identify predictors and a formula to estimate of 1-year postoperative eGFR in the training set, using the CKD-EPI formula. Then, the formula was subjected to internal validation using the validation set using receiver operating characteristic (ROC) curves.

RESULTS

Two hundred and two LLDN were evaluated with a mean preoperative eGFR of 94.1 ± 15.5 ml/min/1.73 m² and postoperative eGFR of 64.6 ± 14.5 ml/min/1.73 m² (p < 0.0001). In multivariable analysis, age and preoperative eGFR were independent predictors of postoperative eGFR in the training set. A formula to estimate postoperative eGFR was generated with Pearson r = 0.70 in the training cohort and 0.65 in the validation cohort (both p < 0.0001). Area under the ROC curve of the formula was 0.89 in the training cohort and 0.83 in the validation cohort (both p < 0.0001).

CONCLUSIONS

Preoperative eGFR and age are predictors of postoperative eGFR after LDN. The internally validated predictive model of postoperative eGFR developed could be an accurate tool to improve the selection of LDN candidates.

Kidney disease progression in patients of upper tract urothelial carcinoma following unilateral radical nephroureterectomy

OBJECTIVES

To compare the renal outcomes in patients of unilateral renal cell carcinoma (RCC) with upper tract urothelial carcinoma (UTUC) following surgical resection of the tumor-bearing kidney, and to investigate the potential predictors in renal function decline.

PATIENTS AND METHODS

In this retrospective cohort study, 319 RCC patients undergoing radical nephrectomy (RN) and 297 UTUC patients undergoing radical nephroureterectomy were recruited from a tertiary medical center between 2001 and 2010. Demographic data, co-morbidity, smoking habit, baseline estimated glomerular filtration rate (eGFR) calculated by chronic kidney disease-epidemiology equation, as well as tumor staging of RCC and UTUC, were recorded. The primary endpoint was serum creatinine doubling and/or end-stage renal disease (ESRD) necessitating long-term dialysis. Cox proportional hazard model and Fine and Gray's competing risk regression accounting for death were used to model renal outcome.

RESULTS

UTUC patients had a higher incidence rate of renal function deterioration than RCC patients did (15.01 vs. 2.68 per 100 person-years, p<0.001). In Cox proportional hazard model and Fine and Gray's competing risk regression, UTUC was significantly associated with increased risk of creatinine doubling and/or ESRD necessitating dialysis (hazard ratio, 3.13; 95% confidence interval, 2.01-4.87) as compared to RCC following unilateral RN. Nevertheless, our study is observational in nature and cannot prove causality.

CONCLUSIONS

UTUC per se is strongly associated with kidney disease progression as compared to RCC following unilateral nephrectomy. Further studies are needed to elucidate this association.

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

OBJECTIVES

To compare post-nephrectomy renal function between kidney donors and renal cell carcinoma patients, to evaluate trends in recovery, and to identify factors relevant to renal failure.

METHODS

Patients who had radical or donor nephrectomy from four different institutions between 2003 and 2012 were reviewed. Propensity score matching was carried out and 79 patients were selected for each group. The estimated glomerular filtration rate was calculated using the Modification of Diet in Renal Disease formula preoperatively and postoperatively at 1, 3, 6, 12, 24 and 36 months. Mean estimated glomerular filtration rate was compared, and the difference between preoperative values and each preceding date was calculated. A multivariate logistic regression was used to determine independent factors for a decrease in estimated glomerular filtration rate to <60 mL/min/1.73 m(2) .

RESULTS

The donor nephrectomy group showed a trend of improved estimated glomerular filtration rate recovery at 24 months and 36 months compared with the radical nephrectomy group, which was statistically significant (P = 0.028, P = 0.012). Multivariate logistic regression showed that renal cell carcinoma (odds ratio 4.605, 95% confidence interval 1.626-13.040, P = 0.004), a baseline estimated glomerular filtration rate lower than 110 (odds ratio 4.477, 95% confidence interval 1.360-14.742, P = 0.014) and age older than 40 years (odds ratio 21.616, 95% confidence interval 2.761-169.222, P = 0.003) were predictive factors for a decrease in renal function.

CONCLUSIONS

Renal cell carcinoma is an independent risk factor for chronic kidney disease after nephrectomy. In addition, age older than 40 years and a baseline estimated glomerular filtration rate of 110 mL/min/1.73 m(2) or less seem to represent risk factors associated with chronic kidney disease after nephrectomy.