Gain and subsequent loss of lung function after lung volume reduction surgery in cases of severe emphysema with different morphologic patterns

Abstract

Objective: Surgical lung volume reduction improves lung function and dyspnea in advanced emphysema to a variable degree. Because long-term results with this procedure are scant, we prospectively investigated lung function over several years after lung volume reduction surgery with regard to emphysema morphology. Methods: Bilateral video-assisted thoracoscopic lung volume reduction surgery was performed in severely symptomatic patients with marked hyperinflation caused by advanced nonbullous emphysema. Emphysema heterogeneity was visually graded on chest computed tomography. Symptoms and lung function were assessed before the operation and 3, 6, and then every 6 months after the operation. Results: A total of 115 patients with a median forced expiratory volume in 1 second of 0.73 L (27% of predicted value) underwent lung volume reduction surgery. Follow-up extended over a median of 37 months. Median forced expiratory volume in 1 second significantly increased within 6 months after the operation by 37% in homogeneous (n = 27), by 38% in intermediately heterogeneous (n = 37), and by 63% in markedly heterogeneous emphysema (n = 51, P < .05 vs other morphologies). Maximal forced expiratory volume in 1 second was reached within 6 months after lung volume reduction surgery and decreased in the first postoperative year by 0.16 L per year in homogeneous, by 0.19 L per year in intermediately heterogenous, and by 0.32 L per year in markedly heterogeneous emphysema (P < .01 vs other morphologies). The decline in forced expiratory volume in 1 second over subsequent years decelerated according to an exponential decay and was similar for all morphologic types (median annual decrease of 0.09 L [9%]). Conclusions: Lung volume reduction surgery improves lung function in severe homogeneous and, to an even greater extent, heterogeneous emphysema. Forced expiratory volume in 1 second peaks within 6 months postoperatively. The subsequent decline is most rapid in the first year and slows down in succeeding years according to an exponential decay. Therefore, long-term functional results of lung volume reduction surgery may be more favorable than expected from linear extrapolations of short-term observations.