Improving survival outcomes in lung transplant recipients through early detection of bronchiolitis obliterans: Daily home spirometry versus standard pulmonary function testing.

Patients diagnosed with advanced lung disease remain significantly symptomatic despite medical therapy and experience statistically high short-term mortality (1). Many of these patients desperately seek symptomatic relief and would consider undergoing lung transplantation to improve their quality of life. Since the first successful heart-lung transplant was performed in 1981 by Dr Bruce Reitz (2), an accepted intervention has emerged for patients with end-stage cardio-pulmonary disease. An estimate by the Global Observatory on Donation & Transplantation in 2011 reported an average of 3200 lung transplants performed each year from 2006 to 2010 worldwide (3), increasing to 3972 in 2012 (4). Although many patients live longer with an improved quality of life after lung transplantation, a significant proportion experience adverse effects and comorbidities, often leading to death sooner after transplant than predicted without (1). The need for investigation is a result of notably poor survival outcomes for lung transplant recipients specifically. According to a 2008 publication from the Registry of the International Society for Heart & Lung Transplantation (ISHLT) (5), lung transplant recipients had an overall median survival of 5.3 years. The registry described long-term survival rates after lung transplantation of 79% at one year, 63% at three years, 52% at five years and 29% at 10 years (5). Survival outcomes for lung recipients remain inferior by nearly one-half of those achieved with other solid-organ transplant procedures. Heart transplant recipients have survival rates of 88%, 75% and 56% at one, five and 10 years, respectively (5,6). Similar differences are apparent with recipients of deceased donor livers, having respective survival rates of 88%, 74% and 60% (5,6). Lung transplantation clearly has a significant early postoperative mortality rate and, often, the recipient may experience significant morbidity associated with transplant and immunosuppression (1). The major cause of death post-lung transplantation has remained constant over the past three decades. Graft failure and infection have been the cause of most acute rejections (ie, first 30 days), whereas bronchiolitis obliterans syndrome (BOS) has been linked to the cause of almost all chronic rejections (ie, after the first year) (7–9). BOS presents as a fibrotic inflammatory process that affects the small airway bronchioles (9). The disease process can be devastating, involving rapidly progressive airways obstruction, eventually leading to respiratory failure (10–12). The development of BOS is believed to be due to chronic graft rejection and has been routinely treated with increased immunosuppression therapy. The concern is that most often, immunosuppression is not successful (9–11). Once BOS is identified, alterations in immunosuppression generally prove, at best, to be only of modest benefit (11). An irreversible decline in forced expiratory volume in 1 s (FEV1) obtained through pulmonary function testing, has shown to be the most well-documented tool to diagnose BOS (11,13). Early intervention, which is essential to improving long-term survival, is dependent on the earliest possible detection. Several studies have suggested that the frequent monitoring of pulmonary function can provide such detection capability (13–19). The relative lack of improvement in lung transplant rejection rates is a concern for an ageing population in which the burden of chronic lung disease is increasing. The present article systematically reviews current research regarding the use of spirometry as a tool for BOS detection in lung transplant recipients, particularly through FEV1 values, and the role home spirometry can play in monitoring for FEV1 changes sooner. A secondary outcome of interest in the present analysis was the impact of early detection using spirometry on survival.