SESSION TITLE: Transplant SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: The reasons why some patients post lung transplantation have an increased propensity for rejection and/or infection is incompletely understood. Although surveillance testing, such as pulmonary function and bronchoscopy for culture and transbronchial biopsies, has been used effectively to identify patients with post-transplant complications, there is a need for more sensitive and non-invasive assays. Fractional exhaled nitric oxide (FeNO) is a simple, widely available, non-invasive, and inexpensive method to indirectly assess increased airway neutrophilia. The objective of this study was to evaluate the use of FeNO trajectory after lung transplantation as a predictive tool for lung function decline in patients post lung transplant. METHODS: The study included all consecutive patients who had undergone bilateral lung transplantation at a single center from January to December 2015. Serial FeNO measurements were done at week 4, 8, 12, 16, 26 and 52 post-transplant. Demographics, pre-transplant diagnosis, lung function, number of infections and instances of biopsy proven rejection on surveillance or clinically indicated bronchoscopy were collected during the 12-month study period. Primary outcome was to assess the clinical correlation between FeNO levels and lung function measured by forced expiratory volume in 1 second (FEV1) percentage change. RESULTS: 29 patients were screened for the study (2 patients died and 4 had single lung transplants). Of the 23 patients included, the most common reason for transplantation was interstitial lung disease (61%), followed by COPD (26%). Rejection and infection was identified in 14 (61%) and 21 (91%) patients, respectively. FeNO levels did not have defined trajectories over time in the whole cohort (R2=0.017), or in those patients that had rejection (R2=0.013). FeNO levels did not correlate with FEV1 in all post-transplant patients (R2=0.001) or those that had rejection (R2=0.001). CONCLUSIONS: FeNO levels were not correlated with either rejection or lung function decline in lung transplant recipients. CLINICAL IMPLICATIONS: Although limited by its sample size, the current study does not support the routine use of serial measurements of FeNO to evaluate for allograft dysfunction in lung transplant recipients. DISCLOSURE: The following authors have nothing to disclose: Diego Maselli, Nina Zatikyan, Benjamin Stephens, Maria Velez, Sergio Burguete, Holly Keyt, Stephanie Levine, Marcos Restrepo, Deborah Levine, Luis Angel No Product/Research Disclosure Information