ACTSI Multi-site Study Finds Association between Expiratory Central Airway Collapse & Poor Respiratory Outcomes in Smokers

Marilyn Foreman, MD, professor of medicine at Morehouse School of Medicine

Expiratory central airway collapse (ECAC) usually occurs in former or current smokers, in which they develop weaker airway walls and experience a flattening or collapse of the central airway during expiration. Many times people are not even aware that this is occurring. With a healthy respiratory system, there is a slight contraction in the airway during expiration – those with ECAC, however, experience a collapse of the airway of as much as 50 percent or more. The airway does return to its prior shape in preparation for the next breath, so many clinicians have supposed that the collapse, while disturbing, is not necessarily dangerous. A multisite team led by Surya Bhatt, MD, assistant professor in the Division of Pulmonary, Allergy, and Critical Care Medicine at the University of Alabama at Birmingham, and Marilyn Foreman, MD, professor of medicine at Morehouse School of Medicine, however, decided to investigate the prevalence of ECAC and its correlation with overall respiratory quality of life. The findings were recently published in The Journal of the American Medical Association (JAMA).

The study team at seven institutions examined 8,820 subjects, both current and former smokers aged 45 to 80, enrolled in a previous large multicenter cohort study, Genetic Epidemiology of COPD (COPDGene), seeking to determine the prevalence and clinical significance of expiratory central airway collapse. This study was supported by Atlanta Clinical & Translational Science Institute’s (ACTSI) Clinical Research Network (CRN) at the Grady Clinical Research Site through nursing support. Through two chest CT scans that observed the trachea both during inhalation and expiration, the team was able to determine that five percent of the study participants were observed to have ECAC. This group was then compared to the control group, investigating the respiratory-related health impairment with quality of life. Researchers also examined other outcomes of ECAC, including shortness of breath, frequency of respiratory issues such as coughing and difficulty breathing that required treatment with antibiotics or steroids, as well as exercise capacity. Across the board, the subjects with ECAC fared worse than those without the condition.

The team concluded that the presence of expiratory central airway collapse is in fact associated with worse respiratory quality of life. In addition, they found that those with lung disease often experience symptoms of ECAC that are not easily explained by their diagnosed illness, just the same as smokers who fail chronic obstructive pulmonary disease (COPD) lung tests. The study suggests that ECAC may contribute to these unexplained symptoms, and may also prove to be some semblance of a biomarker of adverse respiratory events in this patient population. ECAC was also associated with increased incidence of acute respiratory events in those without COPD, and even experience a far higher frequency of severe airway obstructions. Finally, the team concluded that evaluating the presence and effect of ECAC in patients of the future could be of great value to clinicians.  

ACTSI’s Clinical Research Network inpatient and outpatient units provide valuable research implementation services for clinical researchers, including laboratory and nursing services. ACTSI is a city-wide partnership between Emory University, Morehouse School of Medicine, and Georgia Institute of Technology and is one of over 60 in a national consortium striving to improve the way biomedical research is conducted across the country. The consortium, funded through the National Center for Advancing Translational Sciences (NCATS) and the National Institutes of Health’s Clinical and Translational Science Awards, shares a common vision to translate laboratory discoveries into treatments for patients, engage communities in clinical research efforts, and train the next generation of clinical investigators.

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