Outcomes after bronchoscopic lung volume reduction (BLVR) for patients with advanced emphysema were not significantly affected by the level of heterogeneity before the procedure, based on data from more than 200 adults presented at the 2025 European Respiratory Society (ESR) Congress in Amsterdam.

Previous research has suggested that patterns of heterogeneity may affect outcomes after BLVR in patients with heterogenous emphysema, said presenting author Ahmad Raza, MBBS, Department of Thoracic Medicine and Surgery, Temple University Hospital, Philadelphia, in an interview.

In these patients, heterogeneity has been defined as the difference in the percent of emphysematous destruction between the target lobe and the nontargeted ipsilateral lobe, Raza said.

Previous research has established that patients with heterogenous emphysema have a better response to treatment with BLVR than those with homogenous emphysema, but the extent to which the degree of heterogeneity affects outcomes remains unclear, said Raza.

“Various studies have used different cutoffs for heterogeneity, which creates confusion when predicting outcomes with BLVR in discussions with patients and referral physicians; therefore, we decided to study the various degrees of heterogeneity and their impact on outcomes in our patients undergoing BLVR,” he told Medscape Medical News.

Raza and colleagues reviewed data from 206 adults with emphysema who underwent BLVR at a single center between January 2018 and December 2024. The mean age of the patients was 68.4 years, and included 99 women. The patients were divided into three groups according to degree of heterogeneity: less than 10% (group A, 48 patients), 10%-14% (group B, 37 patients), and 15% or higher (group C,121 patients). The researchers compared respiratory function measures at baseline and 6-12 months after BLVR.

Baseline forced expiratory volume in 1 second (FEV₁) was similar across the three groups (approximately 80 L), and the mean residual volume/total lung capacity ratio, a test of air trapping and lung hyperinflation, was similar across the three groups (approximately 61).

Overall, post-procedure change in FEV₁ was significantly different from baseline between the lowest and highest heterogeneity groups (A and C, post-procedure changes of 0.11 L and 0.29 L, respectively; P = .02).

However, no significant changes in FEV₁, or in other outcomes including the 6-minute walk test, the modified Medical Research Council dyspnea scale, or the St. George’s Respiratory Questionnaire were noted between group B and group C, which included patients with heterogeneity greater than 10%.

Results Contradicted Hypothesis

Raza said that he was surprised by the study findings, which adds to the importance of the research. “We hypothesized that a greater degree of heterogeneity would have a greater impact on outcomes post-procedure, but that turned out not to be true,” he said. Instead, the researchers found that, while having heterogenous emphysema of the target lung may confer better patient-related outcomes, the degree of heterogeneity does not matter as much as they thought.

Therefore, the study’s takeaway is that the degree of heterogeneity of emphysema is less important than the presence of air trapping in predicting outcomes of BLVR in patients with advanced emphysema and hyperinflation, Raza told Medscape Medical News.

The study findings were limited by factors including the retrospective design and use of data from a single center that may challenge generalizability, despite the relatively large study population, Raza said. More research is needed to standardize the definition of heterogeneous emphysema, as is research to quantify the volume loss after the BLVR procedure in patients with heterogenous emphysema, he added. “Interestingly, various AI software is being studied to quantify the pre- and post-procedure lobar volume, which would be a novel way to predict outcomes post-procedure,” Raza noted.

The Power of 10%

The current study is important because patterns of emphysema, whether homogenous or heterogenous, affect clinical outcomes after BLVR, said Emily DuComb, MD, interventional pulmonologist at the University of Michigan, Ann Arbor, Michigan, in an interview.

“Further evaluating degree of heterogeneity and how that may impact treatment response makes sense to better understand who responds to BLVR and to what degree,” said DuComb, who was not involved in the study.

“Although various studies have used different cutoff values, my practice is to use 10% for the cutoff for heterogeneity,” DuComb told Medscape Medical News. The finding that heterogeneity beyond 10% was not impactful on outcomes was interesting, she added.

Overall, the current study supports the use of 10% as the threshold value for heterogeneity, but additional research is needed to stratify which patients acquire most benefit from valves, DuComb noted.

The study received no outside funding. Raza and DuComb had no relevant financial conflicts to disclose.