Lung function after bilateral lower lobe lung volume reduction surgery for α1-antitrypsin emphysema

Abstract

This study explores the mechanism(s) of airflow limitation following lung volume reduction surgery (LVRS) in patients with emphysema due to homozygous α1-antitrypsin (AT) deficiency. Bilateral targeted lower lobe stapled LVRS using video thoracoscopy was performed in six patients (five males) aged 61±9 yrs (mean±SD) with α1-AT emphysema. Two patients received only a 6-month follow-up. However, four patients, at 22, 24, 27 and 36 months post-LVRS, noted relief from dyspnoea and increased walk tolerance. At 27±6 months (mean±SD) post-LVRS, their forced expiratory volume in one second improved only from 30±2% of the predicted value (mean±SEM) before surgery to 33±1% pred after surgery. Yet, total lung capacity (TLC) decreased from 151±13 to 127±10% pred; diffusing capacity increased from 35±9 to 59±9% prod; and vital capacity increased from 68±10 to 88±5% pred. In three patients, static lung elastic recoil at TLC increased from 1.1±0.15 to 1.2±0.10 kPa. Using flow/pressure curves, the mechanism for expiratory airflow limitation pre-LVRS and the improvement noted post-LVRS could be primarily accounted for by the initial loss and subsequent increase in lung elastic recoil. Bilateral lung volume reduction surgery provides modest physiologic improvement for 2-3 yrs in patients with α1-antitrypsin emphysema due to increases in lung elastic recoil.