THORACOSCOPIC LASER-ABLATION OF PULMONARY BULLAE - RADIOGRAPHIC SELECTION AND TREATMENT RESPONSE

The purpose of this study was to develop objective preoperative select ion methods for predicting outcome in patients undergoing thoracoscopi c laser ablation of emphysematous pulmonary bullae. Initial radiograph ic presentation was correlated with physiologic function both before a nd after the operation in 24 patients entered into a prospective clini cal protocol for evaluation of carbon dioxide laser treatment of emphy sematous pulmonary bullae. Nineteen surviving patients underwent follo w-up evaluation 1 to 3 months after the operation. Pulmonary function test results showed improvements in spirometry (forced vital capacity increased 0.82 +/- 0.125 L, forced expiratory volume in 1 second incre ased 0.36 +/- 0.07 L, and maximum voluntary ventilation increased 11.6 9 +/- 2.6 L/m; p < 0.002); airway resistance decreased by 0.9 +/- 0.35 cm of water/L per second, and specific conductance increased 0.019 +/ - 0.006 L/cm H2O per second (p < 0.02). Lung volumes improved (residua l volume decreased 1.25 +/- 0.23 L, p < 0.001) without significant cha nge in resting gas exchange. Quantitative radiographic grading of exte nt of preoperative pulmonary bullae correlated well with response to l aser treatment in patients with preoperative and postoperative studies . Patients with large bullae accompanied by crowding of adjacent lung structures, upper lobe predominance, and minimal underlying emphysema had greatest improvement in pulmonary function results with laser bull ae ablation (p < 0.05). However, some patients with multiple smaller b ullae and diffuse emphysema also demonstrated objective improvement af ter operation. Quantitative radiographic analysis of the extent of bul lous disease and the degree of associated emphysema can be used to det ermine short-term postoperative pulmonary response and may be useful i n selecting future thoracoscopic laser bullae ablation candidates. Add itional follow-up will be necessary to further improve selection crite ria and help define the long-term role of thoracoscopic laser treatmen t of bullous emphysema.