Similarities in the Computed Tomography Appearance in α1-Antitrypsin Deficiency and Smoking-Related Chronic Obstructive Pulmonary Disease in a Smoking Collective

Abstract

Background: Emphysematous destruction of lung parenchyma visible in computed tomography (CT) can be attributed to chronic obstructive pulmonary disease (COPD) or to α1-antitrypsin deficiency (AATD). Objectives: We evaluated if visual semiquantitative phenotyping of CT data helps identifying individuals with AATD in a group of smokers with severe emphysema and airflow limitation. Method: n = 14 patients with AATD and n = 15 with COPD and a minimum of 10 pack years underwent CT, clinical assessment, and full-body plethysmography. The extent and type of emphysema as well as large and small airway changes were rated semiquantitatively for each lobe using a standardized previously published scoring system. Lastly, a final diagnosis for each patient was proposed. Results: AATD had a significantly lower mean emphysema score than COPD, with 8.9 ± 3.4 versus 11.9 ± 3.2 (p < 0.001), respectively. Within both groups, there was significantly more emphysema in the lower lobes (p < 0.05–0.001). The COPD group showed an upper- and middle-lobe predominance of emphysema distribution when compared to the AATD group (p < 0.001). Centrilobular (CLE) and panlobular (PLE) emphysema patterns showed a uniform distribution within both groups, with a CLE predominance in the upper lung and a PLE predominance in the lower lung regions. AATD and COPD both showed significantly more airway changes in lower lobes compared to upper lobes (p = 0.05–0.001), without significant differences between both groups. Conclusion: The typical emphysema distribution patterns seen on CT traditionally assigned to AATD and COPD were of little use in discriminating both entities. Also, airway changes could not contribute to a more precise differentiation. We conclude that a concise standardized phenotyping-driven approach to chest CT in emphysema is not sufficient to identify patients with AATD in a cohort of smokers with advanced emphysema.

Towards the elimination of chronic obstructive pulmonary disease: a Lancet Commission

“…Although the emphysema distribution patterns and airway changes are broadly similar between α 1 antitrypsin deficiency-related COPD and COPD unrelated to α 1 antitrypsin deficiency, patients with α 1 antitrypsin deficiency tend to have greater basilar emphysema. 62 The proportion of patients experien cing exacerbations of COPD is similar between α 1 antitrypsin deficiency and non-α 1 antitrypsin deficiency populations.…”

Bronchoscopic Lung Volume Reduction in Patients with Emphysema due to Alpha-1 Antitrypsin Deficiency

“…In contrast, one report on CT appearance of emphysema in AATD versus regular COPD described higher emphysema scores in the RML of patients with regular COPD compared to AATD patients. However, the sample size was very small ( n = 14), and there were no differences in age and pack-years between groups, which questions the investigated AATD phenotype [ 29 ]. In contrast to LIBERATE and IMPACT, AATD was not an exclusion criteria in the TRANSFORM study, although the manuscript does not mention prevalence of AATD in the treated patients group.…”

“…The ZZ phenotype was confirmed in 20 (67%) patients, MZ in 1 patient (3%), and the mutation was unknown in 9 patients (30%) (shown in Table 1). The AATD patients were significantly younger (55 [46-62] versus 64 [59-68] years, p < 0.01) and smoked less (14 [8][9][10][11][12][13][14][15][16][17][18][19][20][21] versus 36 [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] pack-years, p < 0.001). There was no significant difference in FEV 1 , RV, or DL CO , but a less pronounced hyperinflation, based on a significant lower RV/TLC ratio, was present in the AATD group (60 [55-66] versus 64 [60-70], p < 0.05).…”

Clinical significance of serum HMGB1 in COPD and correlation with severity of airflow restriction and immune function

“…In current clinical practices, the pulmonary function index FEV1% pred is usually applied to judge the severity of airflow limitation, while the FEV1/FVC ratio is adopted to assess the impairment of pulmonary function of COPD patients, both of which can be used to determine the disease condition in patients. A study demonstrated that smoking is the most important risk factor for COPD, 10-15% of smokers will suffer from COPD, and at least 95% of COPD patients are smokers (7). Nie found that smoking index (amount of smoking × years of smoking) was remarkably negatively related to the pulmonary function index FEV1 (8).…”