Post-Transplant Outcomes of Novel Surgical Procedures to Deal with Graft Size Mismatch in Living-Donor Lobar Lung Transplantation

Abstract

Various living-donor lobar lung transplant (LDLLT) procedures have been developed in order to resolve the serious issue of graft size mismatch. The purpose of this study was to compare the outcomes of newly developed transplant techniques with those of the standard LDLLT approach. In Kyoto University, the procedures of "native upper lobe-sparing transplant" and "right-left inverted transplant" have been employed as strategies for managing undersized grafts, and single lobar transplant has been used to manage oversized grafts. Between June 2008 and May 2018, we performed 47 standard LDLLT procedures (Standard group), 22 native upper lobe-sparing transplants and/or right-left inverted transplants for undersized grafts (Under group), and 11 single lobar transplants for oversized grafts (Over group). The LDLLT patients showed great early post-transplant outcomes: the ECMO requirement rate was 8.8%, 30-day mortality was 2.5%, and hospital mortality was 5.0%. The pulmonary function at 1 year after LDLLT was similar among the three groups: %FVC of 59%±22% in the Standard group, 63%±19% in the Under group and 61%±21% in the Over group (P = 0.81), and %FEV1 of 59%±20% in the Standard group, 62%±15% in the Under group and 58%±20% in the Over group (P = 0.84). The LDLLT patients had a favorable exercise capacity at 1 year after transplant, as demonstrated by the 6-minute walking distance (Standard: 474±132 m; Under: 525±114 m; Over: 399±81 m, P = 0.08). The incidence of CLAD per graft did not differ markedly among the groups (Standard: 17.4%; Under: 14.3%; Over: 20%, P = 0.87). The overall 5-year survival rate of LDLLT was 79%, and each group showed an excellent 5-year survival rate (Standard: 77%; Under: 74%; Over: 91%, P = 0.67). These novel LDLLT procedures may have resolved the critical size-matching problems between living-donor lobar lungs and recipients, demonstrating favorable post-transplant outcomes.