Bronchial Rheoplasty Unplugs Mucus in Chronic Bronchitis

Bronchial rheoplasty (BR) significantly reduced mucus plugging in adults with chronic bronchitis (CB), based on new data presented at the American Thoracic Society International Conference.

“Mucus plugging, opacities within the lumen of an airway seen on CT scan, is a relatively new measure in COPD that physicians are investigating,” lead author Vincent Kim, MD, of Temple University Hospital, Philadelphia, said in an interview. “These mucus plugs are comprised of excess mucus that cannot be expelled and obstruct the airway from participating in ventilation,” he said.

Previous research has shown an association between mucus plugging seen on chest CT and increased all-cause mortality, Kim and colleagues wrote in their abstract. 

“Mucus plugs can lead to airflow obstruction, hypoxia, exacerbation of COPD, and infection of the lower respiratory tract,” Kim told Medscape Medical News. “The presence of mucus plugging has been related to increased mortality and increased exacerbations, and reducing or eliminating them is associated with clinical improvements in asthma,” he said.

BR to Improve CB

CB is also associated with mucus plugs, and BR has been shown to improve CB symptoms that can last up to at least a year, he noted. Therefore, Kim and colleagues hypothesized that BR could also reduce mucus plugs.

The researchers recruited 52 adult patients with symptomatic CB (defined as Chronic Obstructive Pulmonary Disease [COPD] Assessment Test cough and phlegm scores > 7) who underwent bilateral BR procedures. CT was performed prior to the BR procedure and 6 months after the completion of the BR. The BR procedure involves nonthermal ablation of the airway epithelium and submucosa with pulsed electric fields, the researchers wrote in their abstract.

Mucus plugging was defined as the occlusion of a segmental airway and was assessed as the number of airway segments (out of a total of 18) with one or more mucus plugs. The mean number of airway segments with mucus plugging was 2.9 out of 18 possible segments. A total of 35 patients (67%) showed mucus plugging before the intervention, and 17 did not, despite significant self-reported baseline CB symptoms, the researchers noted.

Among the patients with baseline mucus plugging, the mean mucus plugging score decreased by approximately one segment from 4.3 to 3.4 after the procedure (P = .0392). More than half of the patients with mucus plugging (20 patients, 57%) improved by one segment or more.

In addition, distal airway volume increased by 7.4% at follow-up, and total airway count increased by 4.9 airways. In patients without baseline mucus plugging, 65% continued to have no mucus plugging at 6 months’ follow-up.

Overall, changes in CT measures were consistent with changes in symptom improvement, with mean changes from baseline to follow-up of −6.8 points and 14.5 points on the COPD Assessment Test and St. George’s Respiratory Questionnaire, respectively.

“We were not surprised with the results because of the association previously shown between chronic bronchitis and mucus plugs, and this was a severely symptomatic cohort of chronic bronchitis, with severe cough and phlegm,” Kim said in an interview.

Although the findings were limited by the relatively small study population and lack of randomization, the results suggested that treatment of CB with BR can not only improve respiratory symptoms and health-related quality of life but also decrease mucus plugging, which may translate into a lower risk for mortality and exacerbation, Kim told Medscape Medical News.

Looking ahead, more data are needed, as current studies have not been randomized. “With more randomized clinical trials, we will get a better understanding of the effects of bronchial rheoplasty on mucus plugs, symptom burden, exacerbation risk, and mortality,” he said.

Real-World Data Inform Clinical Practice

Biologic agents have shown effectiveness in reducing asthma exacerbations, and their effectiveness in reducing COPD exacerbations in a real-world setting is an important research question, said Arianne K. Baldomero, MD, assistant professor of medicine, Minneapolis VA Health Care System, Minneapolis, in an interview.

“I’m not surprised by the study results, as clinical trials are showing similar findings among this group of patients with elevated eosinophil counts,” Baldomero told Medscape Medical News. “The evidence supporting the use of biologics to reduce COPD exacerbations is growing stronger. I anticipate that we will soon begin using biologics to manage frequent exacerbations in patients with COPD,” she added. However, “for both asthma and COPD, more research is needed to guide clinicians in tapering or weaning down biologic treatment and determining whether patients still need to use inhalers,” Baldomero said.

Kim disclosed stipends from AstraZeneca and Galvanize Therapeutics for his role as a consultant; Galvanize Therapeutics is the company that developed BR. Baldomero had no financial conflicts to disclose.