Operative candidates were selected on the basis of hyperinflation, heterogeneity of disease, pulmonary perfusion and ventilation deficits, and significant functional disability. Patients with morbid obesity, chronic bronchitis and/or excessive sputum production, metastatic cancer, continued or recent cigarette smoking, or less-than-severe functional disability were excluded from consideration.
Preoperative evaluation included inspiratory and expiratory posteroanterior and lateral chest radiographs as well, and inspiratory and expiratory chest computed tomography (CT) scans. Quantitative ventilation-perfusion scans with xenon washout studies were obtained in all patients, and dobutamine stress thallium studies and/or left-heart catheterization were performed in patients with suspected coronary artery disease. Patients with suspected right-ventricular dysfunction underwent echocardiography and/or right-heart catheterization. All patients were offered preoperative rehabilitation therapy, and the majority participated in a rehabilitation program prior to operation.
Pulmonary function was assessed by standard spirometry, including measurement of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), total lung capacity (TLC), and residual volume (RV), as well as lung volume determination by helium dilution and body plethysmography. Arterial blood gas analysis, cardiopulmonary stress testing, and 6-min walk test were also performed. Finally, patients were asked to subjectively classify their degree of dyspnea according to the Modified Medical Research Council (MRC) Dyspnea Index (15). This screening tool grades the degree of dyspnea on a scale ranging from 0 to 5. Grade 0 represents no functional impairment, and grade 5 represents dyspnea at rest.
Repeated spirometry, 6-min walk test, and dyspnea grading were requested from patients 3-6 mo postoperatively, and at 6-mo intervals thereafter. For purposes of the postoperative data analysis, measurements obtained closest to 6 mo postoperatively were used. Survival status was assessed by contacting all patients directly or through their primary physicians.
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