Adaptation over a Wide Range of Donor Graft Lung Size Discrepancies in Living-Donor Lobar Lung Transplantation

Abstract

Purpose Unlike deceased donor lung transplantation, ideal size matching between donor and recipient is usually difficult because of the limited population of potential donors in living-donor lobar lung transplantation (LDLLT). As a result, there is a wide range of size discrepancies between donor and recipient in LDLLT. The aim of this study was to evaluate the function of the donor graft lung in the recipient thorax after LDLLT in 12 cases of bilateral LDLLT involving 24 successfully transplanted lower-lobe grafts. Methods and Materials Pulmonary function tests and three-dimensional computed tomography (3D-CT) volumetry were performed perioperatively. Results Donor graft volume ranged from 40 to 161% of the hemilateral thoracic volume of the recipient. Graft forced vital capacities (FVC) increased over time, reaching 107 ± 38% of preoperatively estimated values at 12 months after LDLLT. Graft volumes also increased over time, reaching 123 ± 39% of the original values at 12 months postoperatively. As for the association between donor graft FVC ratio to the preoperatively estimated value at 12 months after LDLLT and 3D-CT volumetry size matching, there was a significant correlation between these parameters (r2 = 0.31, p = 0.005, Figure 1). In contrast, there was no significant correlation between donor graft volume ratio to the original value at 12 months after LDLLT and 3D-CT volumetry size matching (p = 0.37, Figure 2). Undersized donor grafts expanded more after LDLLT than oversized donor grafts, producing greater FVCs than the preoperatively estimated values. In contrast, oversized donor grafts became inflated to their original size, and the FVCs also approached preoperatively estimated values. Six-minute walk distance dramatically improved at 3 months after LDLLT in both groups, reaching more than 500 m at 12 months postoperatively. Conclusions In conclusion, we found that donor grafts overinflated or underinflated to the extent that they could maintain their own function in a new recipient environment.