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Lung volume reduction confers clinical benefit in emphysema

Among patients with severe emphysema, lung volume reduction interventions including surgery, endobronchial valves, endobronchial coils or sclerosing agents improved lung function, exercise capacity and quality of life, but these interventions were also associated with increased risk for serious adverse events, according to a systematic review and meta-analysis.

Of 4,747 studies identified for the review, 20 randomized controlled trials of lung volume reduction involving 2,794 patients with emphysema were included.

In pooled analyses, residual volume was reduced by a mean 0.58 L (95% CI, –0.8 to –0.37) with intervention vs. control. In terms of clinical outcomes, forced expiratory volume (FEV₁) increased by 15.87% (95% CI, 12.27-19.47), 6-minute walk distance increased by 43.28 m (95% CI, 31.36-55.21) and St. George’s Respiratory Questionnaire (SGRQ) score decreased by 9.39 points (95% CI, –10.92 to –7.86). The likelihood of experiencing a serious adverse event, however, was higher with intervention vs. control (OR = 6.21; 95% CI, 4.02-9.58), the researchers reported.

They also found a correlation between the degree of reduction in lung volume and improvements in FEV₁ (P < .0001), 6-minute walk distance (P < .0001) and SGRQ score (P < .0001).

Effects of specific interventions

The researchers also evaluated clinical outcomes with each intervention. Surgically treated patients, when compared with standard of care, had a 1.15-L reduction in residual volume (95% CI, –1.6 to –0.7), a 12.71% increase in mean FEV₁ (95% CI, 7.27-18.14), a 10.3-point decrease in SGRQ score (95% CI, –12.45 to –8.15) and a 49.44-m increase in 6-minute walk distance (95% CI, 38.31-60.56). The odds for an adverse event were four times as high for patients treated with surgery vs. standard of care (OR = 4.08; 95% CI, 1.82-9.14).

With endobronchial valves, residual volume decreased by 0.57 L (95% CI, –0.71 to –0.43), FEV₁ increased by 21.77% (95% CI, 17.63-25.9), 6-minute walk distance increased by 49 m (95% CI, 31.89-66.1) and SGRQ score decreased by 9.13 points (95% CI, –12.37 to –5.89), according to the study. The odds for adverse events were also higher with endobronchial valves than with standard of care (OR = 9.58; 95% CI, 5.56-16.5).

With endobronchial coils, there was a 0.32-L reduction in residual volume (95% CI, –0.48 to –0.17), a 10.14% increase in FEV₁ (95% CI, 6.76-13.52) and a 9.69-point decrease in SGRQ (95% CI, –12.25 to –7.14). Six-minute walk distance improved by 29.49 m with intervention vs. control, but the confidence intervals were wide (95% CI, –1.16 to 60.14), according to the researchers. Patients treated with endobronchial coils, as compared with control, were also more likely to experience an adverse event (OR = 8.73; 95% CI, 2.69-28.32).

Treatment with sclerosing agents decreased residual volume by 0.29 L (95% CI, –0.53 to –0.05), improved FEV₁ by 15.07% (95% CI, 9.97-20.18) and decreased SGRQ score by 8.23 points (95% CI, –12.3 to –4.15). Adverse events were also more likely to occur in the treated groups vs. controls (OR = 3.88; 95% CI, 1.6-9.37).

Interpretations

The study was limited by a lack of long-term data and the fact that not all of the studies collected data on all of the parameters included in the analysis. Nevertheless, these results suggest a benefit of lung volume reduction, the researchers noted.

“This systematic review and meta-analysis confirms that interventions designed to reduce lung volume, especially residual volume, in patients with severe emphysema who are hyperinflated and on optimal medical treatment, leads to improvements in lung function, exercise capacity and quality of life,” they wrote. “The relationship between degree of volume reduction and clinical benefit suggests that endobronchial valves and surgery should be considered first depending on the collateral ventilation status and patient choice. Endobronchial coils, AeriSeal and vapor treatment should only be considered as second-line options.” – by Melissa Foster

Disclosures: van Geffen reports receiving an institutional grant from Novartis. Please see the study for all other authors’ relevant financial disclosures.