Expanding the Donor Pool for Transplant Candidates with Congenital Heart Disease: Use of Recipient Total Cardiac Volumes

Abstract

Purpose Donor-recipient matching parameters are based on weight, with the average donor weight within 30% that of the recipient. Patients with congenital heart disease (CHD) may have larger total cardiac volumes (TCV) by computed tomography (CT) than healthy individuals/potential donors. We sought to determine if using the recipient TCV would allow for expansion of the upper donor weight limit. Methods A single center, retrospective study was performed using CT datasets from 13 patients with CHD listed for transplantation, and 94 with structurally normal hearts for comparison. A 3D software platform was used to determine each patients’ TCV. The most recent echo data prior to CT (0-64 days before) was reviewed for presence of ventricular dilation. A TCV control best fit line was determined based on patients with structurally normal hearts. A projected donor weight, based on the TCV for each recipient with CHD, was calculated based on the best fit line. Results Of the 13 CHD patients, 11 (85%) had single ventricle palliation (BT shunt= 2, Glenn= 1, Fontan= 8). Age at TCV assessment ranged from 13 days to 23 years, with weights of 3.6 kg to 79.7 kg. In total, 8/13 patients (62%) had TCVs with corresponding weights on the best fit line >30% larger than their actual weight (figure), the majority having moderate to severe ventricular dilation by echo. TCVs of patients with a BT shunt corresponded to weights 59-86% higher than the recipient's weight. Four Fontan patients had TCVs correlating with weights on the best fit line that were 82-186% above the recipients’ weights. Among those with biventricular repair, TCVs corresponded to weights 174-253% above the recipients’ weight. Conclusion Among the CHD population, a portion have TCVs that correspond to donor TCVs whose weights are 60 to 250% larger than the recipient weights, depending on the diagnosis. We propose using CT-based TCVs when listing CHD patients for heart transplant, rather than weight alone, to expand the donor pool.