Endobronchial valves for lung volume reduction: What can we offer patients with advanced emphysema?
Spiration® Valves
Small trials have shown favorable results with the Spiration® IBV for BLVR, including a pilot multicenter cohort study of 30 patients with heterogeneous, upper-lobe emphysema who underwent valve placement (Wood DE, et al. J Thorac Cardiovasc Surg. 2007;133:65). In this trial, investigators found significant improvement in QOL scores, but no change in FEV1 or other physiologic parameters.
The EMPROVE trial is a multicenter, prospective, randomized, controlled study assessing BLVR with the Spiration® IBV. Six- and twelve-month data from the trial were presented in 2018 at the American Thoracic Society Conference and at the European Respiratory Society International Conference.
Collateral Ventilation
Identifying patients in whom there is no CV between lobes is critical to success with BLVR. Collateral ventilation allows air to bypass the valve occlusion distally, thereby negating the desired effect of valve placement, lobar atelectasis. High-resolution computed tomography (HRCT) scanning combined with quantitative software can be used to assess emphysema distribution and fissure integrity. Additionally, a proprietary technology, the Chartis System®, can be employed intra-procedure to estimate CV by measuring airway flow, resistance, and pressure in targeted balloon-occluded segments. Absence of CV based on Chartis evaluation was an inclusion criterion in the aforementioned valve studies.
Which patients with emphysema should be referred for consideration of valve placement?
The following criteria should be used in selecting patients for referral for BLVR:
• FEV1 15% - 45% of predicted value at baseline
• Evidence of hyperinflation: TLC greater than or equal to 100% and RV greater than or equal to 175%
• Baseline postpulmonary rehabilitation 6-MWT distance of 100 - 500 meters
• Clinically stable on < 20 mg prednisone (or equivalent) daily
• Nonsmoking for at least 4 months
• Integrity of one or both major fissures at least 75%
• Ability to provide informed consent and to tolerate bronchoscopy
Complications
The most common complication after valve placement is pneumothorax – a double-edged sword in that it typically indicates the achievement of atelectasis. In published trials, the frequency of pneumothorax varies. Some studies document rates below 10%. Others report rates of nearly 30% (Gompelmann D, et al. Respiration. 2014;87:485). In landmark trials, death related to pneumothorax occurred rarely. Most severe pneumothoraces occur within the first 72 hours after valve placement. This has prompted many centers to observe postprocedure patients in hospital for an extended period. Pneumonia and COPD exacerbations have also been reported after EBV placement. Therefore, in some trials, patients received prophylactic prednisolone and azithromycin. Other less common complications are hemoptysis, granulation tissue formation, and valve migration.
What’s ahead for ELVR?
Overall, valve technology for BLVR is an exciting option in the management of patients with severe emphysema and is now a staple for any advanced emphysema program. Key areas of future interest include management of patients with partial fissures, minimizing adverse procedural effects, and developing programs to optimize and streamline a multidisciplinary approach to timely and efficient referral, assessment, and intervention. As more patients with COPD undergo ELVR, one goal should be to create multi-institution prospective studies as well as registries to delineate further the optimal use of endobronchial valves for lung volume reduction.
Zephyr® Endobronchial Valve (Pulmonx)
Spiration® Valve System (Olympus)
The American College of Chest Physicians (CHEST) does not endorse or supp
