B46-18 Dynamic Airway Collapse Undermines Endobronchial Lung Volume Reduction: Insights From a Case of Severe Emphysema

Abstract Background Bronchoscopic lung volume reduction (BLVR) using endobronchial valves (EBVs) is established as a minimally invasive strategy for advanced, heterogeneous emphysema. Anatomical prerequisites include complete fissures and absence of collateral ventilation; when fulfilled, BLVR offers targeted lobe atelectasis and decompression of non-targeted regions. However, the unpredictable interplay of airway dynamics with device mechanics in structurally altered lungs and bronchial walls may give rise to novel failure mechanisms rarely described in literature. Case Presentation A 72-year-old ex-smoker with disabling dyspnea and severe lower-lobe dominant emphysema presented for BLVR. Imaging showed marked hyperinflation of the right lower lobe (RLL) compressing upper and middle lobes. Chartis evaluation excluded collateral ventilation; fissures were intact. Two Zephir EBVs (1 EBV n°4 in B6, 1 EBV n°5.5 before the basal pyramid) were deployed to exclude the RLL. Post-procedure, the patient experienced rapid functional and radiological improvement.Two weeks later, the patient developed new-onset hypoxemia and worsening dyspnea. Bronchoscopy—undertaken for suspected valve migration—revealed all valves in place but significant granulation tissue occluding the entrance to the basal pyramid; EBVs were removed to address mucosal inflammation.In the days following removal, the patient’s status declined precipitously with imaging demonstrating acute reexpansion and even more marked hyperinflation of the previously treated RLL. A bronchoscopy revealed pronounced segmental bronchomalacia at the basal pyramid creating a “reverse valve” effect with airway opening during inspiration and airway collapse during expiration causing lobar hyperexpansion. Recognizing this possible “reverse-valve effect,” a new EBV (size 5.5) was deployed proximally, promptly restoring atelectasis with sustained clinical improvement. Discussion This case emphasizes a previously underappreciated paradigm in BLVR: the “reverse-valve effect,” provoked by severe lobar bronchomalacia. Instead of facilitating unidirectional deflation, airway collapse during expiration impedes outflow, while paradoxical opening during inspiration permits reinflation, mapping onto the Starling resistor model of collapsible airways. Device removal, though necessary for granulation, removed mechanical support, accentuating the effect; restorement through upsizing and repositioning achieved therapeutic reversal.Complex emphysematous airways should be evaluated dynamically pre- and post-procedure, with readiness for tailored interventions. Multidisciplinary approach, iterative device management, and awareness of airway mechanics underpin optimal outcomes in BLVR.Within BLVR for emphysema, lobar bronchus malacia can transform EBVs from effective therapeutic agents into unintended facilitators of paradoxical re-inflation. This “reverse-valve effect” demonstrates the primacy of physiology and airway mechanics over device expectations, and the importance of dynamic assessment and adaptive strategy in severe cases. This abstract is funded by: None