Endobronchial Valves for Endoscopic Lung Volume Reduction: Best Practice Recommendations from Expert Panel on Endoscopic Lung Volume Reduction

Abstract

Endoscopic lung volume reduction (ELVR) is being adopted as a treatment option for carefully selected patients suffering from severe emphysema. ELVR with the one-way endobronchial Zephyr valves (EBV) has been demonstrated to improve pulmonary function, exercise capacity, and quality of life in patients with both heterogeneous and homogenous emphysema without collateral ventilation. In this "expert best practices" review, we will highlight the practical aspects of this therapy. Key selection criteria for ELVR are hyperinflation with a residual volume >175% of predicted, forced expiratory volume <50% of predicted, and a 6-min walking distance >100 m. Patients with repeated infectious complications, severe bronchiectasis, and those with unstable cardiovascular comorbidities should be excluded from EBV treatment. The procedure may be performed with either conscious sedation or general anesthesia and positive pressure mechanical ventilation using a flexible endotracheal tube or a rigid bronchoscope. Chartis and EBV placement should be performed in 1 procedure when possible. The sequence of valve placement should be orchestrated to avoid obstruction and delivery of subsequent valves. If atelectasis has not occurred by 1 month after procedure, evaluate valve position on CT and consider replacing the valves that are not optimally positioned. Pneumothorax is a common complication and typically occurs in the first 2 days following treatment. A management algorithm for pneumothorax has been previously published. Long-term sequelae from EBV therapy do occur but are easily manageable.

Fig. 1

X-ray of a typical EBV candidate. Note hyperinflation and subsequent flattening of the diaphragm.

Fig. 2

Quantitative CT reconstruction with fissure rendering illustrating a complete major fissure of left lung, a nearly complete major fissure of the right lung (>95%), and an incomplete minor fissure (<80%). Numbers indicate percent of fissure completeness for the lobe mentioned.

Fig. 3

CT analysis revealing emphysema morphology not recommended for treatment.

Fig. 4

Correct Chartis balloon catheter placement to occlude the right lower lobe (RLL) airway by inflating the balloon and placing it onto the ostium. Note the circumferential blanching of the bronchial wall, indicating the balloon seal and correct position of the catheter tip. ML, middle lobe.

Fig. 5

Chartis system output screen demonstrating assessment time and volume of exhaled air from the target lobe during assessment. Example shows presence of collateral ventilation.

Fig. 6

Chartis procedure showing absence of collateral flow performed under different anesthetic methods. a Positive pressure ventilation. b Conscious sedation. c Jet ventilation.

Fig. 7

Chartis balloon placement occluding the RB6 segment in order to achieve appropriate measurement in the right lower lobe.

Fig. 8

Currently available sizes of Zephyr® endobrochial valves (EBV, Pulmonx) designed to occlude varying bronchial airway lengths, with diameters between 4.0 and 8.5 mm. a EBV-TS-4.0-LP. b EBV-TS-4.0. c EBV-TS-5.5.

Fig. 9

An HRCT scan with homogeneous emphysema distribution (a) with an accompanying perfusion scintigraphy scan indicating areas of lower perfusion especially in the right upper zone (b).

Fig. 10

EBV 4.0 EDC delivery catheter with depth markers illustrating the appropriate length of the valve body for the EBV-TS-4.0-LP (thin blue line) and EBV-TS-4.0 valves (thick blue line).

Fig. 11

EBV delivery catheter width sizing wings used to determine the minimum and maximum diameter of the valve.

Fig. 12

Partial deployment technique illustrating EBV placed directly onto the next distal carina.

Fig. 13

The EBV delivery catheter with a depth marker distal to the ostium ensuring valve housing sits within the target segmental airway.

Fig. 14

Axial reconstruction of a CT image demonstrating poor valve misplacement and subsegmental airflow preventing lobar atelectasis.