High Hyperinflation Predictor of Response in Endobronchial Coil Therapy

Thoracic CT Scan
Thoracic CT Scan
It is important to select patients with significant hyperinflation and a low attenuation area on emphysema score when planning for endobronchial coil therapy.

When planning for endobronchial coil therapy, it is critical to select patients with high hyperinflation (residual volume of ≥200% of predicted value), absence of airways disease in computed tomography (CT) scans, and ≥20% low attenuation area (LAA) on emphysema score. These criteria are associated with better outcomes at 1 year post-treatment, according to research published in CHEST.

This post hoc analysis of the RENEW trial (Lung Volume Reduction Coil Treatment in Patients With Emphysema; ClinicalTrials.gov Identifier: NCT01608490) included 125 individuals who received endobronchial coil therapy and completed 1 year of follow-up. A radiology laboratory performed quantitative analysis, and a team of 5 blinded experts (4 pulmonologists and 1 radiologist) performed qualitative analysis via thoracic CT scans taken at baseline. Participants with ≥15% ipsilateral difference in %LAA950 in both lungs were defined as “heterogeneous,” those with <15% difference were defined as “homogeneous,” and those with one heterogeneous and one homogeneous lung were defined as “mixed.” The relationship between characteristics and clinical response were examined using univariable and multivariable logistic regression.

Treatment of lobes with highest emphysematous destruction (QVM+) occurred in 78 participants, whereas treatment in ≥1 lobes that were not the most destroyed (QVM-) occurred in 47 participants. The QVM+ group showed higher rates of heterogeneity (P <.0005), air trapping (P <.005), and percent emphysema (P <.005) at baseline than the QVM- group. In those receiving QVM+ treatment, 64% (n=50) were observed to have high hyperinflation (residual volume of ≥200% of predicted), no airways disease in CT scans, and >20% LAA on emphysema score. Additionally, this subgroup demonstrated significantly improved forced expiratory volume in 1 second (+15.2±3.1%), residual volume (–0.57±0.13 L), and Saint George’s Respiratory Questionnaire score (–12±2 points; P <.01).

Limitations of this study included the small sample size, retrospective design, and the potential for confounding influences.

The researchers concluded that they “identified three baseline criteria with proposed inclusion thresholds ([residual volume]>200% predicted, emphysema score %LAA>20, and absence of airways disease on visual CT) that defined a patient subgroup achieving clinically significant pulmonary function and volume reduction outcomes at 12-months post coil treatment. Patients selected for lobar volume reduction with endobronchial coil treatment should meet all these criteria, and lobe targets should be confirmed with densitometry analysis to ensure treatment in the lobes of greater destruction.”

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Disclosures: The original RENEW study received financial support from PneumRx, Inc. This post hoc analysis did not. Several authors report financial associations with PneumRx/BTG and other corporations. For a full list of author disclosures, see the reference.


Slebos DJ, Cicenia J, Sciurba FC, et al. Predictors of response to endobronchial coil therapy in patients with advanced emphysema [published online February 21, 2019]. CHEST. doi:10.1016/j.chest.2019.02.012