Survival Benefit of Lung Transplantation in Japan: Extreme Donor Shortage and the Potential Role of Living Transplantation

Abstract

Purpose Cadaveric lung transplantation (LTx) in Japan has multiple limitations including 1) extreme donor shortage (only 44 cadaveric brain-death donors with 37 cadaveric LTx cases across Japan in 2011); 2) limited recipient age below 55 for bilateral and 60 for single LTx; 3) priority of LTx determined solely by waiting time on the list. Thus, living LTx could be the only life-saving option for those who cannot wait for cadaveric LTx. We examined the survival benefit of LTx (either cadaveric or living) among those who were listed for cadaveric LTx in Japan. Methods and Materials The relative risks of death on the waiting list and death after LTx were evaluated using multivariate Cox models. Reception of LTx was treated as censored on the list. Since the initiation of the current Japanese listing system in 1998, patients who were listed by July 31, 2012 were included in the study. Results 617 patients were listed and 174 received LTx (139 cadaveric, 35 living). Average waiting time for cadaveric LTx on the list was 966±676 (10-4507) days. In multivariate Cox regression models, idiopathic pulmonary fibrosis (IPF) showed the most significant risk of death on waiting list (n=115; hazard ratio (HR), 3.53; confidence interval (CI), 2.34-5.31; reference, PAH), while the risk of death after LTx (n=23, including cadaveric (n=15) and living (n=8)) was moderate (HR, 0.85; CI, 0.36-2.01; ref, PAH). Treating the conditions of being on cadacveric-LTx list and being post-LTx as time-dependent covariates, the estimated survival benefit of LTx was most significant in IPF (HR, 0.26; CI, 0.097-0.746). This trend persisted in subanalyses of living and cadaveric LTx. Conclusions IPF showed the most significant survival benefit by LTx. This is explained by their poor prognosis without LTx and reasonable outcome after LTx. Adult-to-adult living LTx, which appears suitable for relatively old IPF patients with small thorax, remains the only life-saving option for many IPF patients who cannot wait for cadaveric LTx.