PURPOSE: Bronchoscopic lung volume reduction (BLVR) therapy utilizing a biological system that remodels and shrinks damaged tissue has been advanced into human trials. Phase 1 results confirm safety and have provided evidence of potential physiological and functional benefit. To further characterize responses to BLVR, transpulmonary pressures were measured during static and dynamic maneuvers.
METHODS: Transpulmonary pressures recorded using an esophageal balloon during static deflation from TLC, forced exhalation, and quiet breathing pre- and 3 months post-BLVR were used to construct lung volume vs pleural pressure profiles (Campbell diagrams) and to calculate lung resistance during inspiration (RLi). BLVR was performed as previously reported.
RESULTS: BLVR at 2 subsegmental sites in three patients produced an 11% increase in PTLC (9.2±2.1cm H2O to 10.3±2.7cm H2O), a 5% reduction in RV (6.0±0.6L to 5.7±0.2L), and a 1% reduction in TLC (9.1±0.4L to 9.0±0.1L), changes associated with a 4% improvement in FVC and 10% increase in 6MWD at 3 months. RLi increased by 10% (7.4±1.2 to 8.2±1.3 cm H2O/L/sec).
CONCLUSION: BLVR at a small number of sites produced favorable changes in lung volumes and elastic recoil pressures, which were associated with improvements in lung function and exercise capacity. Measures of inspiratory resistance did not improve, suggesting that the mechanism of improvement from BLVR is similar to that of conventional LVRS (see Figure 1).
CLINICAL IMPLICATIONS: The data raise the possibility that treatment at additional sites could produce additional benefit. Studies to evaluate the physiological and clinical response to BLVR at higher doses are presently ongoing.
DISCLOSURE: George Washko, None.