Volumetrics and fit assessments for donor to recipient size matching in pediatric heart transplantation: Is it time for a new paradigm?

Abstract

Pediatric heart transplant patients face the highest waitlist mortality in solid organ transplantation. Given the relatively fixed number of donor organs becoming available each year, improving donor organ utilization could potentially have significant impact on reducing waitlist mortality. Donor to recipient weight ratio has historically been used to identify suitable donors; however, this method does not take into account the potential for significant variance in heart size due to complex congenital heart disease or underlying cardiomyopathy. We believe, based on our experience to date, that donor matching based upon weight ratios should be augmented by improved methodologies that provide a more accurate assessment of heart volumes. Herein we describe the rationale for these methodologies and our single‐center experience using volumetrics as an alternative for donor fit assessments.

Reducing the wait: TCV can expand the donor pool for heart transplant candidates

“…While our center has historically been conservative on DRWR, some transplant centers select a less restrictive DRWR of >2 for pediatric patients. 6 However, the actual transplanted DRWR average is 1.64 for these patients and not significantly higher than those with a lower listing DRWR. Our center is cognizant of our conservative DRWR approach and thus has recently begun using CT-derived TCV to inform listing behaviors with this case being the first example.…”

“…Weight-based size matching in pediatric heart transplantation is the current standard; however, weight-based organ matching has not consistently been shown to impact outcomes. [3][4][5][6][7] There are no guidelines for weight ranges and therefore significant practice variation exists in transplant listing, indicating a need for guidance on size matching to enable optimal utilization of the available organs for transplant. 3 Furthermore, the most recent guidelines by the International Society of Heart and Lung Transplantation offer no specific guidance for constraining weight range.…”

“…10 Lacking a heart size measure like PHM in children, TCV-based size matching has recently emerged as a method for more precise organ matching and has demonstrated on numerous occasions the potential to expand the donor pool for listed patients. 1,2,6,11,12 This type of targeted size matching allows avoidance of complications related to oversizing, such as bronchial compression, delayed chest closure, and prolonged length of stay. 13,14 F I G U R E 1 The TCV segmentation is shown in the axial plane (A), coronal plane (B), and 3-dimensional reconstruction (C).…”

A coordinated approach to improving pediatric heart transplant waitlist outcomes: A summary of the ACTION November 2019 waitlist outcomes committee meeting

“…Several centers are utilizing this technology, and the early experience is promising. 35,36 Although it is reasonable to theorize that better size estimations should contribute to increased waitlist survival by expanding the pool of available donors for those listed for transplant, the true impact of more accurate size matching remains unknonwn. 37 Since its inception, the ACTION WOC has been supporting the collaboration of institutions using such technologies and has launched a QI initiative to assess the impact of this intervention, which is currently in the planning phase of…”

“…Current commercially available technology allows for accurate donor‐recipient sizing using three‐dimensional reconstruction of donor heart and recipient cardiac cavities. Several centers are utilizing this technology, and the early experience is promising 35,36 . Although it is reasonable to theorize that better size estimations should contribute to increased waitlist survival by expanding the pool of available donors for those listed for transplant, the true impact of more accurate size matching remains unknonwn 37 .…”