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A1092 - Study of the Etiology and Outcomes in Non-Transplant Related Small Airway Disease
Author Block: R. Krishna, T. Moua; Pulmonary Critical Care Medicine, Mayo Clinic, Rochester, Rochester, MN, United States.
Rationale: Outcomes of transplant related obliterative bronchiolitis have been well documented in the literature, but outcomes related to other etiologies or idiopathic disease is relatively unknown. We reviewed the presentation and long-term outcomes related to non-transplant related small airways disease. Methods: A retrospective review performed with a computer-assisted search of the electronic pathology database from 1990 to 2016 for biopsy proven small airways disease. We included adult patients evaluated in the pulmonary division with pathologic diagnoses of constrictive or follicular bronchiolitis. We studied the underlying etiology, coexisting pulmonary diagnoses, therapies used, presenting pulmonary function and chest CT, and long-term outcomes. A US Social Security Death Index search was used to confirm date of death and all-cause mortality as an outcome. Results: After excluding patients who underwent lung or bone marrow transplantation, we found 76 patients with biopsy proven bronchiolitis. We excluded 26 patients with bronchiolitis reported on biopsy as minor and non-clinical findings, leaving 50 patients for study inclusion. Four patients were diagnosed on transbronchial biopsy, the rest by surgical lung biopsy. Fifteen (30%) patients had constrictive bronchiolitis, 30(60%) had follicular bronchiolitis and 5(10%) had both. Twenty five (50%) patients had idiopathic disease with the other half having diagnosable secondary associations or causes. Nine (36%) patients with secondary associations had common variable immunodeficiency (CVID), all of whom had follicular bronchiolitis. The remaining 16(64%) patients had connective tissue disease (CTD). PFT data was available in 47 patients (92%). Sixteen (34%) had normal spirometry, 22 (46%) had obstructive pattern, 5(10.6%) had restriction, and 4(8%) had nonspecific pattern. In this cohort, the mean FEV1 was 63.8% (SD 21) and mean DLCO was 76.4% (SD 12.4). Chest CT was available in 49 patients. Eighteen (36%) had mosaic attenuation or air trapping. Other prominent imaging features included bronchial wall thickening (24%) and centrilobular nodules (30%). Eleven (22%) patients were treated with inhaled steroids, 6(12%) with macrolides, 7(14%) with both, and 26(52%) did not receive any specific treatment for small airways disease. All-cause mortality was 18% over the study period; six (20%) patients with follicular bronchiolitis and 3 (20%) with constrictive bronchiolitis died. Conclusions: In this largest cohort to date of biopsy-proven small airways disease, causes were equally idiopathic or secondary, with secondary disease dominated by CTD and CVID. Spirometry was predominantly obstructive or normal, with air trapping seen on CT imaging in only a third of patients. All-cause mortality was 18% over the study period.