Comparison of Multiple Diagnostic Tests to Measure Dynamic Hyperinflation in Patients with Severe Emphysema Treated with Endobronchial Coils

PURPOSE: For this study, we aimed to compare dynamic hyperinflation measured by cardiopulmonary exercise testing (CPET), a six-minute walking test (6-MWT), and a manually paced tachypnea test (MPT) in patients with severe emphysema who were treated with endobronchial coils. Additionally, we investigated whether dynamic hyperinflation changed after treatment with endobronchial coils. METHODS: Dynamic hyperinflation was measured with CPET, 6-MWT, and an MPT in 29 patients before and after coil treatment. RESULTS: There was no significant change in dynamic hyperinflation after treatment with coils. Comparison of CPET and MPT showed a strong association (rho 0.660, p < 0.001) and a moderate agreement (BA-plot, 202 ml difference in favor of MPT). There was only a moderate association of the 6-MWT with CPET (rho 0.361, p 0.024). CONCLUSION: MPT can be a suitable alternative to CPET to measure dynamic hyperinflation in severe emphysema but may overestimate dynamic hyperinflation possibly due to a higher breathing frequency

Patient Selection for Bronchoscopic Lung Volume Reduction

Purpose: Bronchoscopic lung volume reduction (BLVR) is a valuable treatment option for carefully selected patients with severe COPD. There is limited knowledge about the characteristics and outcomes of patients referred to a specialized center for BLVR. The study objectives were to investigate the selection rate for BLVR treatment in patients referred for this treatment and to investigate the differences between patients that were selected for BLVR and patients that were not. Patients and Methods: We performed a retrospective analysis of patients with severe COPD who were referred to our hospital to assess eligibility for BLVR treatment. Our parameters included demographics, comorbidity, chest computed tomography characteristics, reasons for rejection from BLVR treatment and patient survival. Results: In total, 1500 patients were included (mean age 62 years, 50% female and forced expiratory volume in 1 s 33% of predicted). Out of this group, 282 (19%) patients were selected for BLVR treatment. The absence of a suitable target lobe for treatment, an unsuitable disease phenotype and insufficient lung hyperinflation were the most important factors for not being selected. Patients that were selected for any BLVR option lived significantly longer than the group of patients that were not selected for BLVR (median 3060 versus 2079 days, P<0.001). Conclusion: We found that only a small proportion of patients that are referred for BLVR treatment is eligible for a BLVR treatment, indicating a need for both better referral tools and for the development of new therapies for this group of patients. Furthermore, our data suggest that selection for BLVR is associated with a significant survival benefit

Significant Differences in Body Plethysmography Measurements Between Hospitals in Patients Referred for Bronchoscopic Lung Volume Reduction

During the evaluation of potential bronchoscopic lung volume reduction (BLVR) candidates in our hospital, we frequently observe patients with a lower residual volume (RV) value compared to the value measured in their referring hospital, although both measured by body plethysmography. We explored to what degree RV and other pulmonary function measurements match between referring hospitals and our hospital. We retrospectively analyzed a total of 300 patients with severe emphysema [38% male, median age 62 years (range 38-81), median forced expiratory volume in 1 s 29% (range 14-65) of predicted, and a median of 40 packyears (range 2-125)]. We measured a median RV of 4.47 l (range 1.70-7.57), which was a median 310 ml lower than in the referring hospitals (range - 3.04 to + 1.94), P < 0.001). In conclusion, this retrospective analysis demonstrated differences in RV measurements between different hospitals in patients with severe emphysema. Overestimation of RV can lead to unnecessary referrals for BLVR and potential treatment failures. To avoid disappointment and unnecessary hospital visits, it is important that body plethysmography measurements are accurately performed by applying preferably the unlinked method in these patients

Identifying Responders and Exploring Mechanisms of Action of the Endobronchial Coil Treatment for Emphysema

Background: So far, 3 randomized controlled trials have shown that the endobronchial treatment using coils is safe and effective. However, the more exact underlying mechanism of the treatment and best predictors of response are unknown. Objectives: The aim of the study was to gain more knowledge about the underlying physiological mechanism of the lung volume reduction coil treatment and to identify potential predictors of response to this treatment. Methods: This was a prospective nonrandomized single-center study which included patients who were bilaterally treated with coils. Patients underwent an extensive number of physical tests at baseline and 3 months after treatment. Results: Twenty-four patients (29% male, mean age 62 years, forced expiratory volume in 1 s [FEV1] 26% pred, residual volume (RV) 231% pred) were included. Three months after treatment, significant improvements were found in spirometry, static hyperinflation, air trapping, airway resistance, treated lobe RV and treated lobes air trapping measured on CT scan, exercise capacity, and quality of life. The change in RV and airway resistance was significantly associated with a change in FEV1, forced vital capacity, air trapping, maximal expiratory pressure, dynamic compliance, and dynamic hyperinflation. Predictors of treatment response at baseline were a higher RV, larger air trapping, higher emphysema score in the treated lobes, and a lower physical activity level. Conclusions: Our results confirm that emphysema patients benefit from endobronchial coil treatment. The primary mechanism of action is decreasing static hyperinflation with improvement of airway resistance which consequently changes dynamic lung mechanics. However, the right patient population needs to be selected for the treatment to be beneficial which should include patients with severe lung hyperinflation, severe air trapping, and significant emphysema in target lobes