Radiologic and Clinical Features of COPD Patients With Discordant Pulmonary Physiology: Lessons From α1-Antitrypsin Deficiency

摘要

Introduction: Subjects with COPD display heterogeneity in clinical, physiologic, and radiologicncharacteristics, which are thought to result from different pathophysiologic mechanisms. It isnimportant to identify and understand specific phenotypes for patient management. We investi-ngated differences in emphysema distribution and health status in u00011-antitrypsin deficient subjectsn(PiZ) with discordant lung function.nMethod: CT scan densitometry, arterial oxygen tension, and St. George respiratory questionnairenscores were compared for 15 subjects with normal FEV1 and lung diffusion capacity corrected fornalveolar ventilation (KCO), both defined as > 80% predicted (group 1), 10 subjects with abnormalnFEV1 and normal KCO (group 2), 15 subjects with normal FEV1 and abnormal KCO (group 3),nand 10 subjects with both an abnormal FEV1 and KCO (group 4).nResults: Group 2 subjects had the greatest predominance of basal emphysema, and group 3nsubjects had the least. Upper zone voxel index (ie, the percentage of voxels < u0002910 Hounsfieldnunits) was greater in all groups with abnormal lung function (p u0003 0.003, 0.044, and < 0.001,nrespectively), indicating more upper zone emphysema than in subjects with normal lung function.nLower zone voxel index was increased in groups 2 and 4 compared to groups 1 and 3. Groups 2nand 4 had a lower PaO2 (p < 0.001) than the other groups. All groups with abnormal lung functionnhad a worse quality of life than those with normal lung function.nConclusion: Abnormality of FEV1 is associated with basal-predominant emphysema, and abnor-nmality of KCO is associated with relatively more upper zone emphysema; but, an isolated defectnin KCO has a significant effect on health status. (CHEST 2007; 132:909–915)