Does preserved kidney volume predict 1 year donor renal function after laparoscopic living donor nephrectomy?

Abstract

Abbreviations & Acronyms BMI = body mass index BSA = body surface area CKD = chronic kidney disease CKD3 = chronic kidney disease level 3 Coef = regression coefficient CT = computed tomography EBL = estimated blood loss eGFR = estimated glomerular filtration rate IQR = interquartile range MDRD = Modification of Diet in Renal Disease OR = operation room WIT = warm ischemia time. Abstract: The aim of the present study was to evaluate whether preserved kidney volume predicts donor renal function at 1-year post-surgery. Data of patients who underwent laparoscopic living donor nephrectomy between October 2006 and September 2010 were retrospectively reviewed. All patients underwent computed tomography scan with an estimation of kidney volume by using an automated segmentation algorithm. We also calculated kidney volume adjusted for donor body surface area and donor preserved kidney volume ratio (split volume). Estimated glomerular filtration rate was estimated using the Modification of Diet in Renal Disease equation. Predictors of the estimated glomerular filtration rate at 1 year were assessed by multiple linear regression. The 1-year estimated glomerular filtration rate was available in 140 patients. The median age was 40 years, and median adjusted preserved kidney volume was 160.5 cc/1.73 m 2 (interquartile range 143.7-177.9). Median estimated glomerular filtration rate was 92.4 (interquartile range 81.9-101.2) and 61.2 mL/min/1.73 m 2 (interquartile range 53.4-68.7), respectively, at baseline and at 1 year. Preserved kidney volume adjusted to body surface area (P = 0.02) with age (P = 0.002) and preoperative estimated glomerular filtration rate (P < 0.001) were independent predictors of estimated glomerular filtration rate at 1 year. However, split kidney volume was not statistically related to estimated glomerular filtration rate at 1 year (P = 0.47). In order to maximize preservation of donor renal function, the pre-donation kidney volume adjusted to body surface area might be a useful parameter to consider when deciding on living kidney donation. Correspondence

Association of mGFR of the Remaining Kidney Divided by Its Volume before Donation with Functional Gain in mGFR among Living Kidney Donors

“…Age has already been shown to be inversely associated with shortterm postdonation GFR (17,29) and also, long-term postdonation GFR (5,24), and initial BMI was reported to be negatively associated with postdonation GFR (30). Taken together, these results suggest that older and heavier living donors have less functional nephrons available and/or a less compensatory hypertrophy capacity in the remaining kidney.…”

“…It has already been reported that larger kidney volume estimated by CT scan was associated with better graft function (13)(14)(15). It has also been shown that the initial preserved kidney volume adjusted for body surface area is correlated with donor renal function at 6 months (31) and 1 year postdonation (17). However, it has never been reported before, to our best knowledge, that the initial kidney volume and its corresponding rk-GFR should be considered simultaneously using the rk-GFR/vol parameter to predict functional gain.…”

“…Consequently, the combination of predonation GFR measurement and nuclear SRF enables us to calculate the initial GFR of the remaining kidney (rk-GFR). Furthermore, it has been suggested that measurements of the volumes of the kidney to be donated and the remaining kidney using renal computed tomography scan (CT scan) are predictive of subsequent renal functions in the recipient (13)(14)(15) and the donor (16,17), respectively.…”

Does size matter? Kidney transplant donor size determines kidney function among living donors

“…Although preserved kidney volume has been identified as a predictor of donor eGFR 6 months [36] and 1 year after donation [38] by multivariate logistic regression analysis, no study to our knowledge has examined how kidney size determines rate of renal recovery and the risk of non-recovery to an eGFR ≥60 mL/min/1.73 m 2 post-nephrectomy.…”

CT volumetry is superior to nuclear renography for prediction of residual kidney function in living donors

“…In light of the limitations of nuclear renography, several investigators have examined the feasibility of using CT‐based techniques for estimating differential kidney function . Several of these studies have used proportional kidney volume by CT volumetry to estimate split kidney function, with the underlying premise that kidney volume is a reliable surrogate for kidney function in healthy patients .…”