Masafumi Yamaguchi

A Mixed Phenotype of Airway Wall Thickening and Emphysema Is Associated with Dyspnea and Hospitalization for Chronic Obstructive Pulmonary Disease

RATIONALE Quantitative computed tomography (CT) has been used to phenotype patients with chronic obstructive pulmonary disease (COPD). A mixed phenotype is defined as the presence of both airway wall thickening and emphysema on quantitative CT. Little is known about patients with COPD with the mixed phenotype. OBJECTIVES To propose a method of phenotyping COPD based on quantitative CT and to compare clinically relevant outcomes between patients with COPD with the mixed phenotype and those with other CT-based phenotypes. METHODS Each of 427 male smokers (187 without COPD, 240 with COPD) underwent a complete medical interview, pulmonary function testing, and whole-lung CT on the same day. The percentage of low-attenuation volume at the threshold of -950 Hounsfield units (%LAV) and the square root of wall area of a hypothetical airway with an internal perimeter of 10 mm (Pi10) were measured. Patients with COPD were classified into four distinct phenotypes based on the upper limits of normal for %LAV and Pi10, which were derived from the data of smokers without COPD by using quantile regression. MEASUREMENTS AND MAIN RESULTS Of 240 patients with COPD, 52 (21.7%) were classified as CT-normal phenotype, 39 (16.3%) as airway-dominant phenotype, 103 (42.9%) as emphysema-dominant phenotype, and 46 (19.2%) as mixed phenotype. Patients with COPD with the mixed phenotype were associated with more severe dyspnea than those with each of the remaining CT-based phenotypes (P < 0.01 for all comparisons). The number of hospitalizations for COPD exacerbations during the preceding year was 2.0 to 3.6 times higher in patients with the mixed phenotype than in those with each of the remaining CT-based phenotypes (P < 0.05 for all comparisons). Findings persisted after adjustment for age, pack-years of smoking, smoking status, body mass index, and FEV1. CONCLUSIONS Patients with COPD with the mixed phenotype are associated with more severe dyspnea and more frequent hospitalizations than those with each of the remaining CT-based phenotypes. Thus, patients with COPD with the mixed phenotype may need more attention and interventions.

Airway wall area derived from 3-dimensional computed tomography analysis differs among lung lobes in male smokers.

Background It is time-consuming to obtain the square root of airway wall area of the hypothetical airway with an internal perimeter of 10 mm (√Aaw at Pi10), a comparable index of airway dimensions in chronic obstructive pulmonary disease (COPD), from all airways of the whole lungs using 3-dimensional computed tomography (CT) analysis. We hypothesized that √Aaw at Pi10 differs among the five lung lobes and √Aaw at Pi10 derived from one certain lung lobe has a high level of agreement with that derived from the whole lungs in smokers. Methods Pulmonary function tests and chest volumetric CTs were performed in 157 male smokers (102 COPD, 55 non-COPD). All visible bronchial segments from the 3rd to 5th generations were segmented and measured using commercially available 3-dimensional CT analysis software. √Aaw at Pi10 of each lung lobe was estimated from all measurable bronchial segments of that lobe. Results Using a mixed-effects model, √Aaw at Pi10 differed significantly among the five lung lobes (R2 = 0.78, P<0.0001). The Bland-Altman plots show that √Aaw at Pi10 derived from the right or left upper lobe had a high level of agreement with that derived from the whole lungs, while √Aaw at Pi10 derived from the right or left lower lobe did not. Conclusion In male smokers, CT-derived airway wall area differs among the five lung lobes, and airway wall area derived from the right or left upper lobe is representative of the whole lungs.

Mediastinitis and pericarditis after endobronchial ultrasound‐guided transbronchial needle aspiration

A 73‐year‐old man was admitted to our hospital for further investigation of multiple lung nodules and lymphadenopathy that were observed on chest radiography. Endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) was performed to sample the lower paratracheal lymph node (4R), leading to a definitive diagnosis of squamous cell carcinoma of the lung. About 2 weeks after EBUS‐TBNA, the patient had a high temperature, anterior chest pain, tachycardia, and hypotension. The diagnosis of infectious mediastinitis and pericarditis as complications of EBUS‐TBNA, which were successfully treated with systemic antibiotics, was made after examinations. EBUS‐TBNA is minimally invasive and useful for the diagnosis of hilar and mediastinum lesions particularly in determining the extent of lung cancer. With the increased employment of this method, critical complications may also increase. Clinicians should be aware of the rare but critical complications associated with EBUS‐TBNA.

Relative contributions of emphysema and airway remodelling to airflow limitation in COPD: Consistent results from two cohorts

The relative contributions of emphysema and airway remodelling to airflow limitation remain unclear in chronic obstructive pulmonary disease (COPD). We aimed to evaluate the relative contributions of emphysema and airway wall thickness measured by quantitative computed tomography (CT) to the prediction of airflow limitation in two separate COPD cohorts.

Assessment of inhalation flow patterns of soft mist inhaler co-prescribed with dry powder inhaler using inspiratory flow meter for multi inhalation devices

The patients’ inhalation flow pattern is one of the significant determinants for clinical performance of inhalation therapy. However, the development of inhalation flow meters for various inhalation devices has been unable to keep up with the increasing number of newly launched inhalation devices. In the present study, we developed simple attachment orifices for the inhalation flow pattern monitoring system, which are suitable for all commercial inhalers, and investigated the efficacy of the system on the clinical inhalation instruction for patients co-prescribed dry powder inhaler (DPI) and soft mist inhaler (SMI). First, we constructed simple attachment orifices that were adjusted for 13 commercial inhalers, and examined the correlation between orifice and inhalation device. Second, the inhalation flow patterns (peak inspiratory flow rate, PIFR; inhalation duration time, DT) of patients prescribed a combination of DPI and SMI were monitored before and after inhalation instruction. The inhalation resistance of commercial inhalers are listed in the following order; Twincaps® > Handihaler® > Swinghaler® = Clickhaler® > Twisthaler® > Turbuhaler® > Jenuair® > Diskus® = Ellipta® > Diskhaler® > Breezhaler® > Respimat® = pMDI. The pressure drop via orifice was significantly correlated with that via the commercial inhaler. For the confirmation, all participants achieved the DPI criterion of PIFR. On the other hand, 4 participants (6 clinical visits) of 10 experimented participants could not achieve the essential criterion of DT (> 1.5 sec) for SMI, but all participants improved their duration time after inhalation instruction by pharmacists (P<0.05). In the present study, we successfully developed simple attachment orifice suitable for 13 commercial inhalation devices. These data suggested that our simple attachment orifices for the inhalation flow pattern monitoring system can detect patients with inadequate inhalation patterns via SMI.

Behavioral Changes in General Practitioners towards Chronic Obstructive Pulmonary Disease Over Five Years: An Observational Study.

OBJECTIVE Early detection of chronic obstructive pulmonary disease (COPD) is critical for preventing progression; however, the disease is rarely detected in the early stages. One reason for this is that COPD is not generally recognized and diagnosed by general practitioners (GPs). The objective of this study was to observe changes in the knowledge and behavior of GPs regarding the diagnosis and treatment of COPD over a five-year period. METHODS The surveys were performed using identical and anonymous questionnaires in 2005, 2006 and 2010. During this period, various educational campaigns were conducted. MATERIALS All members of the Shiga Medical Association working as GPs in Shiga Prefecture. RESULTS The number of questionnaires collected was 216 of 711, 269 of 731 and 326 of 856, respectively. Throughout the study period, the number of doctors who prescribed inhaled long-acting muscarinic antagonists (LAMAs) significantly increased (p<0.001). However, there were no significant changes in the rate of possession of spirometers or recognition of COPD guidelines. When we focused on the data for internists, the rate of recognition of the guidelines increased significantly (p<0.01), despite a lack of change in the rate of possession of spirometers. Furthermore, the results of the multivariate analysis revealed that increased knowledge concerning COPD was associated with the doctors specialty, ownership of a spirometer, number of COPD patients attending their clinic and their level of recognition of the guidelines. CONCLUSION During the study period, the GPs prescribed more inhaled LAMAs. The rate of recognition of COPD guidelines was also increased among internists. Educational campaigns may be more effective if the backgrounds of the GPs are taken into consideration.