Is It Time to Expand the Criteria for Bronchoscopic Lung Volume Reduction in Very Low FEV1 and DLCO Emphysema

Abstract

T he National Emphysema Treatment Trial (NETT) found increased mortality and limited functional improvement in patients with forced expiratory volume in 1 s (FEV1) ≤ 20% and either homogeneous emphysema or diffusing capacity of the lungs for carbon monoxide (DLCO) ≤ 20%, who underwent surgical lung volume reduction (SLVR) compared to medical treatment. 1 Subsequently, randomized control trials for bronchoscopic lung volume reduction (BLVR) excluded patients with FEV1 or DLCO ≤ 20%. 2,3 Given 2 decades have passed since the NETT trial finding, it is time to reexamine the literature on the lung physiologic parameters exclusion criteria in BLVR. METHODSWe searched PubMed and Embase from inception to February 16, 2024, employing search terms: "very low FEV1" OR "very low DLCO" AND emphysema AND "valve" OR "coil" OR "vapor" OR "sealant." We included only primary studies of adult patients with COPD and severe emphysema, hyperinflation, very low FEV1 and/or DLCO ( ≤ 20%) who underwent BLVR. BLVR included valves (Spiration/Zephyr), coil, vapor, or sealant. Exclusion criteria were non-English articles, abstracts, case reports, or small case series ( < 10 subjects). RESULTSA total of 64 articles were identified that addressed BLVR in very low FEV1 and/or DLCO. Most were excluded during the screening of titles and abstracts because they were not research studies or enrolled in a different population than desired (Fig. 1). Ten articles were retrieved for full-text review, from which 6 articles were selected. [4][5][6][7][8][9] These included 5 studies on valve placements, 4-8 and 1 on coil placement. 9 The inclusion criteria for heterogeneous/ FIGURE 1. PRISMA flowchart.