Lung volume reduction using one-way endobronchial valves is a bronchoscopic treatment for patients with severe emphysema without collateral ventilation between the treatment target lobe and the ipsilateral lobe(s). CT-scan fissure analysis is often used as a surrogate to predict the absence of collateral ventilation. We aimed to evaluate the predictive value of the fissure completeness score (FCS) compared to the functional Chartis measurement of collateral ventilation and to provide cut-off values of the FCS in patient selection.

Multicenter study in patients eligible for treatment with one-way valves. The FCS was calculated by quantitative CT analysis (Thirona, the Netherlands) and compared to status of interlobar collateral ventilation measured with Chartis system (PulmonX, USA). Thresholds were calculated for the predictive values of the presence of collateral ventilation.

An FCS >95% of the left major fissure had a positive predictive value (PPV) of 91%, with 1 in 11 fissures demonstrating collateral ventilation with Chartis measurement, whereas an FCS of ≤80% had a negative predictive value (NPV) of 100% for the presence of collateral ventilation. For the right major fissure, the NPV was 100% for an FCS ≤90%, but 69.7% for the right upper lobe fissure.

Quantitative CT analysis is recommended in all patients evaluated for endobronchial valves. Patients with incomplete fissures (left major fissure: FCS <80%; right major fissure: <90%) can be excluded from Chartis measurement and endobronchial valve treatment. In patients with more complete fissures, the FCS is not specific enough for endobronchial valve treatment decisions. In this case, additional Chartis measurements are always recommended in the right lung. For the left lung, Chartis assessments may be omitted if the FCS is >95%.