Lung volume reduction surgery: a meta-analysis of randomized clinical trials.

Background: Observational studies have suggested that lung volume reduction surgery (LVRS) is superior to optimal medical therapy for selected subsets of patients with advanced emphysema. Randomized clinical trials (RCTs) with the exception of the National Emphysema Treatment Trial (NETT), failed to enroll a sufficient number of patients to provide clinicians and patients with convincing outcome data on the usefulness of LVRS. It was postulated that a meta-analysis of these RCTs (3-12 months' follow up) may provide more compelling information on the value of LVRS in patients with emphysema.

Methods: A comprehensive search of the MEDLINE database between January 1994 and January 2004 for RCTs on LVRS was performed.

Results: From a total of eight RCTs on record, six studies (306 patients) with 3- to 12-month follow up were deemed suitable for meta-analysis. Key baseline features of these RCT populations included heterogeneous emphysema, comparable inclusion/exclusion criteria and, in retrospect, low walking capacity as measured by the 6-minute walk distance (6MWD). This profile closely resembles NETT's 'predominantly upper lobe--low exercise tolerance emphysema' cohort. The LVRS arm of the meta-analysis population showed better results than the medical cohort in terms of pulmonary function (FEV(1) p < 0.0001, FVC p < 0.0001, residual volume p < 0.0001, total lung capacity p = 0.004), gas exchange (arterial partial pressure of oxygen p < 0.0001) and exercise capacity (6MWD p = 0.0002). Although information on quality-of-life measures was not sufficiently uniform to qualify for meta-analysis, a survey of available data revealed better results in the surgical than in the medical arms of each RCT. Mortality 6-12 months after random assignment to treatment was similar in the two study arms, suggesting that the operative mortality from LVRS was offset, within months, by deaths in the medical arm.

Conclusions: This meta-analysis showed that a selected subset of patients with advanced, heterogeneous emphysema and low exercise tolerance (6MWD) experienced better outcomes from LVRS than from medical therapy.