Indications for lung transplant referral and listing

Since the introduction of successful lung transplant in the early 1980’s, the field of lung transplantation has seen considerable improvement in terms of candidate selection, management and outcomes. The selection process of appropriate candidates is a meticulous one. Identifying the patients who will have a clear survival benefit is one of the challenging aspects of lung transplant. Prior to 2005, lungs were allocated based solely on time on waiting list. This was unfavorable to patients with more rapidly progressing disease like idiopathic pulmonary fibrosis (IPF) who had higher mortality while waiting for transplant. The Department of Health and Human Services published the “Final Rule” In 1998 which directed the Organ Procurement Transplant Network (OPTN) to formulate policies to ensure (I) broader sharing of organs, (II) reducing the use of waiting time as an allocation criterion, and (III) equitable organ allocation using objective medical criteria and medical urgency for allocation (1). Because of the Final Rule, the Lung Allocation Score (LAS) was created and implemented in 2005. The International Society for Heart and Lung Transplantation (ISHLT) has published several consensus statements/guidelines on the selection and listing criteria for lung transplant in 1998, 2006 and 2015 (2-4). Despite the growing body of scientific evidence, these statements remain largely based on expert opinion, and are subject to change in light of emerging evidence. The LAS serves to prioritize lung transplant candidates based on waitlist mortality and post-transplant survival by creating a model, which is supposed to reflect a net gained post-transplant survival. In the LAS, lung disease diagnoses are divided into four main categories: (A) obstructive lung disease (chronic obstructive pulmonary disease or COPD); (B) pulmonary vascular disease (idiopathic pulmonary arterial hypertension or IPAH); (C) infectious lung disease [cystic fibrosis (CF)]; and (D) restrictive lung diseases (IPF). We herein review the most common indications for lung transplant referral and listing in each of these categories, represented by one disease for each category. We will also discuss other factors in the prognostication of some diseases and their potential impact on prioritization of lung transplant recipients