Prospective Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Jun 29, 2020; 10(6): 173-182
Published online Jun 29, 2020. doi: 10.5500/wjt.v10.i6.173
Living kidney donor assessment: Kidney length vs differential function
Jacob A Akoh, Katharina J Schumacher
Jacob A Akoh, Katharina J Schumacher, Department of Surgery, Derriford Hospital, University Hospitals Plymouth NHS Trust, Plymouth PL6 8DH, Devon, United Kingdom
Jacob A Akoh, South West Transplant Centre, Derriford Hospital, University Hospitals Plymouth NHS Trust, Plymouth PL6 8DH, Devon, United Kingdom
Author contributions: Akoh JA and Schumacher KJ collected data; Akoh JA: designed study, analysed data, wrote paper, and critically appraised manuscript; Schumacher KJ collected data and wrote aspects of paper; all authors have read and approved the final manuscript.
Institutional review board statement: The study was reviewed and approved by the University Hospitals Plymouth NHS Trust Institutional Review Board. Ethics approval and individual informed consent was not required.
Clinical trial registration statement: Not Applicable for this Manuscript.
Informed consent statement: Not Applicable for this Manuscript.
Conflict-of-interest statement: Both authors have no conflict of interests to declare.
Data sharing statement: There is no additional data available.
CONSORT 2010 statement: The authors have read the CONSORT 2010 Statement, and the manuscript was prepared and revised according to the CONSORT 2010 Statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Jacob A Akoh, FRCS (Ed), FRCS (Gen Surg), MBBS, Associate Professor, Consultant General and Transplant Surgeon, Department of Surgery, Derriford Hospital, University Hospitals Plymouth NHS Trust, Derriford Road, Plymouth PL6 8DH, Devon, United Kingdom. jacob.akoh@nhs.net
Received: February 24, 2020
Peer-review started: February 24, 2020
First decision: April 18, 2020
Revised: May 19, 2020
Accepted: May 21, 2020
Article in press: May 21, 2020
Published online: June 29, 2020
Processing time: 119 Days and 15.2 Hours
Abstract
BACKGROUND

The key question in living kidney donor assessment is how best to determine the contribution of each kidney to overall renal function and guide selection of which kidney to donate, ensuring safety of procedure and good outcome for both recipient and donor. It is thought that a length difference > 2 cm may indicate significant difference in function and therefore need for measurement of differential function.

AIM

To determine the effect of using kidney length to decide which kidney to donate in a retrospective cohort of potential donors.

METHODS

All 333 potential living kidney donors between January 2009 and August 2018 who completed assessment were retrospectively evaluated. Donor assessment was performed as per United Kingdom guidelines. Data included age, sex, kidney length (cranio-caudal) obtained by computed tomography/ultrasono-graphy,51-chromium ethylenediamine tetraacetatic acid measured glomerular filtration rate, mercapto acetyl tri glycine split function and vascular anatomy. There were 48 exclusions due to inadequate data or incomplete investigations. Statistical analysis was performed using Excel pivot tables and GraphPad Prism. Correlation between kidney length and differential function was determined with Pearson’s correlation coefficient.

RESULTS

Of 285 potential donors included in the study, there were 144 males (mean age 49.9 ± 14.75) and 141 females (mean age 51.2 ± 11.23). Overall, the Pearson’s correlation between differences in length and divided function of kidney pairs was 0.1630, P = 0.0058. Of 73 with significant difference (> 10%) in divided function, 18 (24.7%) had no difference in kidney length; 54 (74%) had a difference of < 2 cm and only one of > 2 cm. Using a length difference of > 1 cm would only predict significant difference in divided function in 8/34 (23.5%) of cases. Using a difference of > 2 cm as cut off for performing split function would lead to false reassurance in 72 patients (6 had > 20% difference in divided function whereas 66 had 10%-20% difference).

CONCLUSION

Length difference between kidney pairs alone is not sufficient to replace measurement of divided function. This issue requires a randomised controlled trial to resolve it.

Keywords: Kidney transplantation; Living kidney donor assessment; Kidney length; Kidney volume; Differential function; Glomerular filtration rate

Core tip: Selection of which kidney to donate is of critical importance in living kidney donation. The decision-making process based on divided function and vascular anatomy was used to validate a retrospective “what if” analysis of prospectively reported kidney length measurements in a cohort of 285 potential donors. This study shows a significant risk for making wrong/harmful decision (removing the significantly better functioning kidney) if kidney length alone is used for decision making -25% if using 2 cm difference as cut off. Difference in length between kidney pairs alone is not sufficient to replace measurement of divided function.