The Lung Microbiome and Endobronchial Valve Treatment

Overview

Lung emphysema is an incurable disease and is often associated with chronic obstructive pulmonary disease (COPD). Dyspnea is the main, debilitating symptom and is relieved by inhaled bronchodilators and rehabilitation. However, a substantial number of patients continue to suffer from dyspnea, and among these, many patients have severe hyperinflated lungs due to emphysema. For selected patients, lung transplantation or lung volume reduction by surgical removal (LVRS) of the most emphysematous parts of the lungs can improve symptoms and survival. However, LVRS has a relatively large risk of adverse events, and therefore not all patients are suitable for surgery. An alternative to LVRS is bronchial lung volume reduction with endobronchial valves (EBV), where one-way valves are inserted in the bronchial system. It has emerged as a valid treatment option, with reduction of hyperinflation and increased pulmonary function, quality of life, and exercise capacity. The normal lung is colonized with several types of bacteria, and together these are called the microbiome. Some bacteria are potentially beneficial, while others are potentially harmful. After the insertion of EBVs, some patients develop chronic infections. The hypothesis is that the microbiome can affect the risk of chronic infection, and therefore the objective of this study is to assess the microbiome during the insertion of the EBVs and afterwards observe which patients develop chronic infection and whether these patients are harboring specific bacterial species.

The objective of this study is primarily to investigate the effect of the lung microbiome on outcomes and morbidity after EBV treatment. Second, to investigate the evolution of the lung microbiome in patients later requiring valve removal or clean-up. Before the insertion of the EBV, during the procedure, the patient will undergo a bronchoalveolar lavage (BAL). BAL fluid will be used for bacterial profiling through 16S ribosomal analysis and conventional bacterial culture. The number of infections and the need for clean-up or valve removal will be registered during the following 24 months, during which the patient follows the ordinary follow-up programme. As a secondary part of the study, during potential clean-up or valve removal, the removed material will again undergo 16S ribosomal analysis and culture to investigate shifts in the microbiome.