Limited Benefit of Additional Chartis® Assessments for Collateral Ventilation Evaluation in Patients with Software Quantified Intact Target Lobe Fissure – Results from a Retrospective Analysis of the German Lung Emphysema Registry

Background: Endoscopic lung volume reduction (ELVR) with valves is a treatment option for selected patients with emphysema. Collateral Ventilation (CV) is measured directly with the Chartis ® bronchoscopic assessment system (PulmonX Inc. Redwood City, CA, USA) and indirectly via fissure completeness score (FCS) on computed-tomography (CT). It remains unclear, whether the additional Chartis ® assessment improves treatment outcome when the target lobe shows intact fissure (FCS ≥ 95%). Study Design and Methods: This retrospective analysis used data from the German Lungenemphysemregister e.V. a prospective multicenter trial on lung volume reduction therapy. Patients with an intact fissure (FCS ≥ 95%) of the target lobe undergoing ELVR were included. Treatment outcomes were compared between patients who had a Chartis ® measurement prior to ELVR and those who did not. Results: A total of 262 patients were analyzed: 175 with Chartis ® and 87 without. Baseline parameters were comparable between groups. At 3-month follow-up significant improvements in lung function parameters (FEV1, RV, DLCO, pCO2), exercise capacity (6-MWT) and quality of life parameters (SGRQ, mMRC and CAT) were seen in both groups. Treatment efficacy at 3-month follow-up was comparable in patients regardless of previous Chartis ® measurements. Furthermore, there was no difference in treatment outcome, when comparing improvements for the right and left lung separately. Responder rates were similar between the groups, with a comparable MCID in both. Complication rates were also largely comparable, except for a higher pneumothorax rate in the no-Chartis group (7% vs 22%). Discussion: This analysis did not find evidence that a Chartis ® assessment provided additional benefit to the treatment response after ELVR at 3-month follow-up in patients with an intact fissure of the target lobe with an FCS ≥ 95%. These findings may be clinically relevant as they suggest that additional invasive Chartis ® measurement might be dispensable in this subgroup.