Efficacy of three-dimensional computed tomography volumetry for recipients in downsizing oversized grafts in brain-dead donor lung transplantation

Abstract

Objective: Brain-dead donor lung transplantation frequently requires reduction in the size of oversized lung grafts for patients with a small chest cavity. We focused on the role of three-dimensional computed tomography (3D-CT) volumetry for recipients on downsizing oversized lung grafts.

Methods: We performed 53 brain-dead donor bilateral lung transplantations, including 15 lobar lung transplants (Lobar group) and 38 standard lung transplants with full-sized grafts (Full group), between December 2010 and December 2018. Recipient chest volume before transplantation was measured using 3D-CT volumetry, and donor lung volume was evaluated by predicted total lung capacity. Post-transplant outcomes and pulmonary function were retrospectively compared between the groups.

Results: The ratio of the recipient chest volume to the donor lung volume was significantly lower in the Lobar group (0.42 ± 0.15) than in the Full group (0.77 ± 0.30, P < 0.01). The calculated size matching between the donor and recipient after downsizing the grafts was significantly correlated to the ratio of the recipient chest volume to the donor lung volume (Spearman r = 0.69; P < 0.01). Early post-transplant outcomes did not significantly differ between the groups. Although the Full group showed slightly better pulmonary function after transplantation, the 1-, 3-, and 5-year overall survival rates were similar to the Lobar group (100%, 93%, and 81% in the Lobar group vs. 92%, 78%, and 70% in the Full group; P = 0.50).

Conclusions: Brain-dead donor lobar lung transplantation showed favorable post-transplant outcomes. The assessment of recipient chest cavity volume using 3D-CT volumetry may help surgeons precisely downsize oversized lung grafts prior to transplantation.

Keywords: Brain dead donor; Lobar lung transplantation; Oversized graft; Three-dimensional computed tomography volumetry.

Fig. 1

Donor to recipient size matching was performed using predicted vital capacity. Donor-to-recipient size matching was significantly decreased after downsizing (pre-downsizing: 117.9 ± 8.5% vs. post-downsizing: 82.6 ± 14.6%, P < 0.01) in brain-dead lobar lung transplant patients. The size matching between donor and recipient was significantly higher before downsizing and lower after downsizing in the Lobar group than in the Full group (P < 0.01). The data of the Full group (100.5 ± 13.0%) were indicated by red color dotted line

Fig. 2

Significant correlation was observed not before (Spearman r = 0.34, P = 0.21) but after downsizing the donor lung grafts (Spearman r = 0.69, P < 0.01) between the donor-to-recipient size matching and the ratio of recipient chest volume to donor lung volume. Recipient chest volume was evaluated by three-dimensional computed tomography volumetry, while donor lung volume was assessed by the predicted vital capacity. Two patients who underwent lobar lung transplantation due to infection were indicated by red color plots

Fig. 3

Post-transplant pulmonary function, %vital capacity (%VC) and %forced expiratory volume in 1 s (%FEV1) of predicted values, was slightly better in the Full group (a). The 6-min walking distance (6MWD) did not differ between the groups except at 3 months after transplantation (b). *P < 0.05

Fig. 4

The 1-, 3-, and 5-year overall survival rates were 100%, 93%, and 81% in the lobar transplant group and 92%, 78%, and 70% in the full lung transplant group (P = 0.50)