Rate of FEV1 change following lung volume reduction surgery

Introduction: Lung volume reduction surgery (LVRS) improves pulmonary function and dyspnea symptoms acutely in selected patients with heterogeneous emphysema. Limited data are available regarding long-term function following LVRS. We analyzed short-term (<6 months) and long-term rate of change of pulmonary function in 376 patients who underwent unilateral or bilateral LVRS using thoracoscopic or median sternotomy, staple, laser, or combined techniques. We hypothesized that the long-term rate of deterioration in lung function would be dependant on the surgical procedure used and would be greatest in those with the largest short-term postoperative improvement. Methods: Pulmonary function was assessed preoperatively and at repeated intervals following LVRS. The change in pulmonary function over time was assessed for each patient by determining the individual change in FEV1 using linear regression analysis short and long term. Overall rate of change in pulmonary function was calculated for the composite group of patients and subgrouped by operative procedure. Results: Lung function appears to improve in the first few months following LVRS in most patients, maximising at approximately 3 to 6 months and declining thereafter. The short-term incremental improvement following staple procedures is superior to improvements following laser procedures or unilateral surgery: FEV1 increase (mean+/-SD) of 0.39+/-0.03 L for bilateral staple, 0.25+/-0.83 L for unilateral staple, 0.10+/-0.03 L for unilateral laser, and 0.22+/-0.1 L for mixed unilateral staple/laser procedures. However, the long-term rate of decline in FEV1 was greatest for bilateral staple LVRS procedures as well: 0.255+/-0.057 L/yr for bilateral staple, 0.107+/-0.068 L/yr for unilateral staple, 0.074+/-0.034 L/yr for unilateral laser, and 0.209+/-0.12 L/yr for mixed staple laser procedures. There was a general correlation between the magnitude of short-term incremental improvement and the rate of deterioration in FEV1 (r=0.292, p=0.003). Conclusions: While bilateral staple LVRS procedures lead to greater short-term improvement in FEV1, the more rapid rate of FEV1 decline in these patients and the general association between greater short-term incremental improvement and higher rates of deterioration raise questions regarding optimal long-term procedures. Further studies will be needed to answer these important questions.