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World J Transplant. Mar 24, 2016; 6(1): 155-164
Published online Mar 24, 2016. doi: 10.5500/wjt.v6.i1.155
Donor to recipient sizing in thoracic organ transplantation
Michael Eberlein, Robert M Reed
Michael Eberlein, Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States
Robert M Reed, Division of Pulmonary and Critical Care Medicine, University of Maryland, Baltimore, MD 21201, United States
Author contributions: Eberlein M and Reed RM contributed to this paper in conception and design, acquisition, analysis and interpretation of data, and drafting the article and revising it critically for important intellectual content; all authors approved this version to be published.
Supported by Flight Attendants Medical Research Institute in part (to Robert M Reed); Michael Eberlein is supported by a PILOT grant from the Institute for Clinical and Translational Science (ICTS) at the University of Iowa via the National Institutes of Health (NIH) Clinical and Translational Science Award (CTSA) program, grant 2 UL1 TR000442-06.
Conflict-of-interest statement: There is no conflict of interest associated with any of the senior author or other coauthors contributed their efforts in this manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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/
Correspondence to: Michael Eberlein, MD, PhD, Division of Pulmonary, Critical Care and Occupational Medicine, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, C 33 GH, Iowa City, IA 52242, United States. michael-eberlein@uiowa.edu
Telephone: +1-319-3561265 Fax: +1-319-3536406
Received: July 29, 2015
Peer-review started: August 19, 2015
First decision: September 22, 2015
Revised: November 17, 2015
Accepted: December 7, 2015
Article in press: December 8, 2015
Published online: March 24, 2016
Abstract

Donor-to-recipient organ size matching is a critical aspect of thoracic transplantation. In the United States potential recipients for lung transplant and heart transplant are listed with limitations on donor height and weight ranges, respectively. Height is used as a surrogate for lung size and weight is used as a surrogate for heart size. While these measures are important predictors of organ size, they are crude surrogates that fail to incorporate the influence of sex on organ size. Independent of other measures, a man’s thoracic organs are approximately 20% larger than a woman’s. Lung size can be better estimated using the predicted total lung capacity, which is derived from regression equations correcting for height, sex and age. Similarly, heart size can be better estimated using the predicted heart mass, which adjusts for sex, age, height, and weight. These refined organ sizing measures perform better than current sizing practice for the prediction of outcomes after transplantation, and largely explain the outcome differences observed after sex-mismatch transplantation. An undersized allograft is associated with worse outcomes. In this review we examine current data pertaining to size-matching in thoracic transplantation. We advocate for a change in the thoracic allocation mechanism from a height-or-weight-based strategy to a size-matching process that utilizes refined estimates of organ size. We believe that a size-matching approach based on refined estimates of organ size would optimize outcomes in thoracic transplantation without restricting or precluding patients from thoracic transplantation.

Keywords: Lung transplant, Heart transplant, Organ size, Size mismatch, Organ allocation

Core tip: Recipients for lung transplant and heart transplant are listed with acceptable donor height and weight ranges as surrogates for organ size, respectively. While these measures are important predictors of organ size, they are crude surrogates that fail to incorporate the influence of sex on organ size. Lung size can be better estimated using the predicted total lung capacity (derived from height, sex and age). Similarly, heart size can be better estimated using the predicted heart mass (derived from sex, age, height, and weight). These refined organ sizing-measures perform better than current sizing practice for the prediction of outcomes after transplantation.