Small airway disease may be a potential long-lasting effect following COVID-19, according to a new prospective study published Tuesday in Radiology.
Reports have emerged that more than half of individuals who survive the disease may suffer from “long COVID,” with almost 30% experiencing lingering respiratory symptoms. University of Iowa scientists recently put a new CT protocol in place, gathering images of post-COVID patients both inhaling and exhaling. Such “expiratory” chest CT allowed researchers to see potential air trapping, signifying that patients are unable to completely empty their lungs when breathing out.
The study enrolled 100 COVID-19 survivors, including 67 classified as ambulatory, 17 who were hospitalized and 16 who visited the intensive care unit. Comparing their imaging results against 106 healthy patients revealed stark differences. Average percentage of the total lung affected by air trapping landed at more than 25% among the ambulatory cohort, versus nearly 35% for those hospitalized, and just 7.2% in the control group.
“For the first time, we’re describing small airways disease in this population of COVID-19 patients with persistent symptoms. Something is going on in the distal airways related to either inflammation or fibrosis that is giving us a signal of air trapping,” study author Alejandro Comellas, MD, a professor of internal medicine at the Carver College of Medicine in Iowa City, said in a statement.
“If a portion of patients continues to have small airways disease, then we need to think about the mechanisms behind it,” he added later. “It could be something related to inflammation that’s reversible, or it may be something related to a scar that is irreversible, and then we need to look at ways to prevent further progression of the disease.”
Comellas et al. conducted their single-center study between June and December of 2020, enrolling adults who remained symptomatic more than 30 days following their COVID diagnosis. They utilized artificial intelligence to aid in the measurement of ground glass opacities in the lungs, along with gauging the level of air trapping.
Among the hospitalized and ICU groups, the average percent of total lung classified as GGO was 13% and 29%, respectively. The intensive care unit group also saw average air trapping of more than 27%. Comellas and colleagues noted that this air trapping persisted among 8 of the 9 participants who underwent CT more than 200 days following their diagnosis. Median time from that point to chest CT was about 75 days, with such persisting abnormalities raising potential concern for permanent airway remodeling and fibrosis, the authors advised.
Read more of the study in the Radiological Society of North America’s flagship journal, along with a corresponding editorial.
Marty Stempniak has covered healthcare since 2012, with his byline appearing in the American Hospital Association's member magazine, Modern Healthcare and McKnight's. Prior to that, he wrote about village government and local business for his hometown newspaper in Oak Park, Illinois. He won a Peter Lisagor and Gold EXCEL awards in 2017 for his coverage of the opioid epidemic.