Quantitative Computed Tomography Analysis of the Longitudinal Change Between Centrilobular and Paraseptal Emphysema Subtypes: A Retrospective Study.

OBJECTIVE: This study aimed to investigate the difference between the extent of centrilobular emphysema (CLE) and paraseptal emphysema (PSE) on follow-up chest CT scans and their relationship to the cross-sectional area (CSA) of small pulmonary vessels. METHODS: Sixty-two patients (36 CLE and 26 PSE) who underwent 2 chest CT scans were enrolled in this study. The percentage of low attenuation volume (%LAV) and total CSA of the small pulmonary vessels <5 mm 2 (%CSA < 5) were measured at the 2 time points. Analysis of the initial %CSA < 5 and the change in the %LAV and %CSA < 5 on follow-up imaging was performed. RESULTS: The initial %CSA < 5 was not significantly different between the CLE and the PSE groups (CLE, 0.66 vs. PSE, 0.71; P = 0.78). There was no significant difference in the longitudinal change in the %LAV between the 2 groups (CLE, -0.048% vs. PSE, 0.005%; P = 0.26). The longitudinal change in the %CSA < 5 in patients with PSE significantly decreased compared with those with CLE (CLE, 0.025% vs. PSE, -0.018%; P = 0.02). CONCLUSIONS: The longitudinal change in the %CSA < 5 was significantly different for patients with CLE and PSE, demonstrating an important pathophysiological difference between the subtypes.

Ring-Opening Metathesis Polymerization of endo- and exo-Norbornene Lactones.

New ester-functionalized bicyclic aliphatic polymers are synthesized through the ring-opening metathesis polymerization (ROMP) of endo- and exo-norbornene lactones (endo-NBL and exo-NBL) and their oxa-norbornene analogue (exo-oxa-NBL) followed by hydrogenation. The polymerizability between endo- and exo-NBLs, and the thermal properties between the six types of polymers before and after hydrogenation are compared and discussed. The ROMP of all three monomers proceeded in a living fashion under optimized conditions, which is confirmed by chain extension experiments. Endo-NBL shows a much lower homo- and copolymerizability than exo-NBL probably owing to six-membered chelation to the Ru center and steric hindrance in the ruthenacyclobutane intermediate. Stereo-block and stereo-gradient copolymers of poly(endo-NBL) and poly(exo-NBL) are also synthesized. The hydrogenation catalyzed by RuHCl(CO)(PPh3 )3 in the mixed solvents of o-xylene and N,N-dimethyl acetamide (DMAc) results in more than 95% conversion. The obtained hydrogenated polymers, H-poly(endo-NBL) and H-poly(exo-NBL), are amorphous, soluble in chlorinated aliphatic solvents, and thermally stable until 400 °C without a weight loss. Their glass transition temperatures are 163 and 131 °C, respectively; the values are appropriate in terms of both thermal stability and processing deformation for the application of transparent resin materials.

Correlation between heart size and emphysema in patients with chronic obstructive pulmonary disease: CT-based analysis using inspiratory and expiratory scans.

The objective of this study was to investigate the relationship between the extent of emphysema and heart size in patients with chronic obstructive pulmonary disease (COPD) using inspiratory and expiratory chest computed tomography (CT). This retrospective study was approved by the institutional review board and informed consent was waived. We measured lung volume (LV), low attenuation area percent (%LAA; less than or equal to -950 HU), maximum cardiac area, and maximum transverse cardiac diameter on inspiratory/expiratory chest CT in 60 patients with COPD. Spearman rank correlation analysis was used to determine the correlations between the heart and lung CT measurements, and the correlations between these measurements and spirometric values. On inspiratory CT, the maximum transverse cardiac diameter was negatively correlated with LV ( ρ = -0.42; p < 0.01) and %LAA ( ρ = -0.43; p < 0.001). Furthermore, on expiratory CT, the maximum cardiac area was negatively correlated with LV ( ρ = -0.35; p < 0.01) and %LAA ( ρ = -0.37; p < 0.01), and there was a negative correlation between transverse cardiac diameter and %LAA ( ρ = -0.34; p < 0.01). Although inspiratory cardiac size was not correlated with any of the spirometric values, the maximum cardiac area and transverse diameter on expiratory scans were significantly correlated with the reduced airflow values on spirometry ( p < 0.01). In patients with COPD, the transverse cardiac diameter decreased as the emphysema progressed. A smaller cardiac area on expiratory CT suggested the presence of large LVs, emphysema, and airflow limitation in COPD.

N-Heterocyclic Carbene Initiated Anionic Polymerization of (E,E)-Methyl Sorbate and Subsequent Ring-Closing to Cyclic Poly(alkyl sorbate).

A diene-based cyclic polymer has been synthesized by the anionic polymerization of methyl sorbate (MS) by an N-heterocyclic carbene (NHC) in the presence of a bulky aluminum Lewis acid. We first polymerized methyl sorbate (MS) initiated by NHC in N,N-dimethylformamide (DMF) at 25 °C, poly(MS) with a number-average molecular weight (Mn) of 3.5 × 103 (Mw/Mn = 2.1) was obtained with a conversion of 93%. The structure was confirmed by 1H and 13C NMR and IR spectra, which revealed that the propagation proceeded via 1,2-addition as well as 1,4-addition. Although the polymerization did not occur in toluene in the absence of any additive, quantitative monomer consumption was observed in the presence of methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD) to afford the poly(MS) with a 1,4-trans structure, 86% of threo diastereoselectivity, and a Mn of 23.0 × 103 with narrow molecular weight distribution (Mw/Mn = 1.17). From the matrix assisted laser desorption/ionization (MALDI-TOF) mass spectra of poly(MS) and the hydrogenated analogue, ring-closing occurred by nucleophilic attack of the anionic propagating center into the adjacent carbon of the α-terminal imidazolimium group to afford cyclic poly(MS). The cyclic formation in the present synthesis system was confirmed by DSC and viscosity measurements.

Decrease in Small Pulmonary Vessels on Chest Computed Tomography in Light Smokers Without COPD: An Early Change, but Correlated with Smoking Index.

PURPOSE: The aim of this study was to evaluate the relationship between the amount of smoking and the cross-sectional area (CSA) of small pulmonary vessels in light smokers without a diagnosis of chronic obstructive pulmonary disease (COPD). METHODS: This retrospective study was approved by our institutional review board, which waived the need for informed consent from patients. The study included 34 current smokers without COPD, who were defined as light smokers based on their smoking history (≤25 pack years). The CSA of small pulmonary vessels (<5 mm2 [CSA<5]) was measured on computed tomography (CT) scans, and the percentage of total CSA of the lung (%CSA<5) was calculated. The extent of emphysema was also assessed as the percentage of low attenuation area (%LAA, <-950 Hounsfield units). The correlations of %CSA<5 and %LAA with pack years were determined using the Spearman rank correlation. RESULTS: There was a significant negative correlation between %CSA<5 and pack years, whereas no significant correlation was found between %LAA and pack years. The correlations between pack years and percent predicted forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity were not significant. CONCLUSIONS: The percentage of total CSA of the lung made up of small pulmonary vessels in light smokers without COPD significantly decreases with increasing amount of smoking, in contrast to emphysema measurements. This suggests that small pulmonary vessels might have been injured or might have degenerated because of smoking, and might represent an initial stage in the development of COPD.

Thiol-Mediated Controlled Ring-Opening Polymerization of Cysteine-Derived ß-Thiolactone and Unique Features of Product Polythioester.

The controlled ring-opening polymerization of the ß-thiolactone derived from N-Boc cysteine was achieved using N-Boc-L-cysteine methyl ester as the initiator in NMP at room temperature. The propagating end is the thiol group, which attacks the carbonyl to open the monomer ring by the C(═O)-S bond scission. A thiol-ene click reaction demonstrated the utility of the thiol group at the propagating terminal. The block copolymer was efficiently produced by the terminal coupling of the polythioester with the norbornene terminated PEG. As another interesting reaction, the polythioester underwent the main chain transformation to polycysteine through the intramolecular S-to-N acyl migration, triggered by the deprotection of the pendant Boc groups. The polythioester from L-cysteine showed Cotton effects between 200 and 300 nm in the circular dichroism (CD) spectrum. Although the CD pattern resembled that produced by the α-helix of polypeptide, it was ascribable not to the second structure but to the relative orientation of the thioester and carbamate carbonyls in the repeating unit.

Regional Lung Sound Asynchrony in Chronic Obstructive Pulmonary Disease Patients.

BACKGROUND: Regional lung sound distribution in chronic obstructive pulmonary disease (COPD) is reported to be asynchronous. Mathematical analyses using vibration response imaging (VRI), such as left and right lung asynchrony (gap index; GI) and regional lung asynchrony (asynchrony score; AS), are useful measures to evaluate lung sound asynchrony. OBJECTIVES: The aim of this study was to investigate the association of lung sound asynchrony with pulmonary functions and emphysematous lesions in COPD patients. METHODS: VRI recordings and pulmonary function tests were performed in 46 stable male COPD patients and in 40 healthy male smokers. Lung sound asynchrony was evaluated using GI, AS of the left and right lung (AS L-R), and AS of the upper and lower lung (AS U-L). In 38 patients, computed tomography taken within 6 months was available and analyzed. RESULTS: AS L-R and AS U-L were significantly higher in COPD patients than in healthy smokers, with no significant difference in GI. There were no significant correlations with either AS and pulmonary functions, excluding a negative correlation between AS U-L and diffusion capacity. Although there were no significant correlations between both AS and severity of emphysema, significant positive correlations were observed between heterogeneity of emphysematous lesions and AS L-R (ρ = 0.38, p < 0.05) or AS U-L (ρ = 0.51, p < 0.005). CONCLUSIONS: Regional lung sounds are distributed more asynchronously in COPD patients than in healthy smokers, which correlates with the heterogeneous distribution of emphysematous lesions.

Morphological disease progression of combined pulmonary fibrosis and emphysema: comparison with emphysema alone and pulmonary fibrosis alone.

OBJECTIVES: The purpose of this study was to evaluate the differences in 5-year morphological changes among the patients with combined pulmonary fibrosis and emphysema (CPFE), emphysema alone, and fibrosis alone using quantitative computed tomography evaluation. METHODS: This study involved 42 patients with CPFE, 45 patients with emphysema alone, and 35 patients with fibrosis alone who underwent computed tomography scans twice (initial and 5 years after the initial scan). The extent of emphysematous lesions was obtained by calculating the percentage of low attenuation area (%LAA) lower than -950 Hounsfield units. Fibrotic lesion was defined as a high attenuation area (HAA) using thresholds with pixels between 0 and -700 Hounsfield units, and the extent of fibrosis was obtained by calculating the mean percentage of HAA (%HAA). For the quantitative evaluation of the total area of emphysematous change and fibrosis, the percentage of destructed lung area (%DA) was obtained by summing %LAA and %HAA. The 5-year changes of %LAA, %HAA, and %DA were calculated. Differences were evaluated by 1-way analysis of variance, which was followed by the Tukey-Kramer test. RESULTS: The mean change of %LAA was significantly higher in CPFE (7.4% ± 3.8%) than in emphysema alone (P < 0.05). The mean change of %DA was significantly higher in CPFE (12.9% ± 5.8%) than in emphysema alone (4.9% ± 2.8%) and fibrosis alone (7.1% ± 5.7%). CONCLUSIONS: Morphological disease progression in CPFE differed from that in emphysema alone or fibrosis alone. In particular, the increase in emphysematous low-attenuation lesions was significantly higher in CPFE.

Quantitative Computed Tomography Measurement of Tracheal Cross-Sectional Areas in Relapsing Polychondritis: Correlations with Spirometric Values.

BACKGROUND: Although tracheal stenosis occurs in relapsing polychondritis (RP), no studies exist that have clarified correlations between quantitative airway measurement and spirometry in RP patients. OBJECTIVES: The aim of this study was to investigate correlations between the cross-sectional area (CSA) of the trachea and spirometric values in patients with RP. METHODS: The institutional review board approved this retrospective study, and written informed consent was waived. Twenty-six patients with RP underwent spirometry and chest computed tomography (CT) at full inspiration and end-expiration. On inspiratory and expiratory chest CT images, CSA at the intrathoracic trachea was measured for all CT slices, and the mean and minimum tracheal CSA were obtained. Correlations between the tracheal CSA and spirometric values were assessed by Spearman's rank correlation analysis. Results: Tracheal CSA measurements for inspiratory and expiratory scans were significantly correlated with FEV 1 , FEV 25-75% , and peak flow values (ρ = 0.51-0.86, p <0.01). During each inspiratory or expiratory phase, the minimum tracheal CSA achieved a higher correlation coefficient with spirometric values than the mean CSA. CONCLUSION: Tracheal dimensions for both inspiratory and expiratory CT are significant predictors of pulmonary function in patients with RP. The narrowest tracheal dimension likely determines the severity of airflow limitation in RP.

Changes in the superior vena cava area during inspiration and expiration in relation to emphysema.

BACKGROUND: In patients with emphysema, increased intrathoracic pressure is closely related to hyperinflation and leads to hemodynamic impairments. Both intrathoracic pressure and hemodynamics such as venous return are affected by the respiratory phase. Therefore, respiratory variations in hemodynamics may be associated with the extent of emphysema that causes increased intrathoracic pressure. The current study was designed to evaluate the relationship between respiratory phasic variations in the area of the superior vena cava (SVC) and the extent of emphysema. METHODS: We measured the SVC area and calculated the ratio of the SVC area in inspiratory and expiratory scans (i/e-SVC ratio) in 101 patients with emphysema who underwent both inspiratory and expiratory CT. The correlation of the i/e-SVC ratio with the extent of emphysema (%LAA) obtained by CT images was evaluated. Multiple linear regression analysis using i/e-SVC ratio as the dependent variable was performed. RESULTS: The i/e-SVC ratio had a significant positive correlation with%LAA (ρ = 0.582, p <0.0001). The i/e-SVC ratio was significantly higher in patients with severe emphysema (0.86 ± 0.13) than in patients with mild-moderate emphysema (0.69 ± 0.13) (p <0.0001). Multiple linear regression analysis showed that%LAA was the only independent predictors of the i/e-SVC ratio (r(2) = 0.471, p = 0.0006). CONCLUSION: Respiratory phasic variations in the SVC area are significantly correlated with the extent of emphysema.

Cooperative N-heterocyclic carbene/Brønsted acid catalysis for the tail-to-tail (co)dimerization of methacrylonitrile.

The first tail-to-tail dimerization of methacrylonitrile (MAN) has been realized by the cooperative use of N-heterocyclic carbene (NHC) and Brønsted acid catalysts, producing 2,5-dimethylhex-2-enedinitrile with the E/Z ratio of 24:76. Although the NHC alone was not effective for the catalysis, the addition of alcohols resulted in the significant increase of the dimer yield up to 82% in the presence of 5 mol % NHC. Detailed experimental studies including the ESI-MS analysis of the intermediates, stoichiometric (co)dimerizations, and deuterium-labeling experiments revealed the mechanistic aspects of the proton transfer, isomerization, umpolung, and rate-limiting steps, allowing us to observe several mechanistic differences between the dimerization of MAN and that of methyl methacrylate. The stoichiometric reactions in the presence and absence of an alcohol suggest that the alcohol additives play a role in promoting the intermolecular proton transfers from the deoxy-Breslow intermediate to the regenerated NHC in the second half of the catalytic cycle. In addition, the codimerizations of MAN with n-butyl methacrylate (n-BuMA) have been studied. While the dimerization of n-BuMA was sluggish in the presence of an alcohol, the catalytic activity for the codimerization was enhanced by the cooperative systems.

MRI of pulmonary nodules.

OBJECTIVE: The purpose of this article is to review the current status of MRI for evaluation of pulmonary nodules. CONCLUSION: Although clinical applications of pulmonary MRI face technical limitations, currently available MRI methods have contributed to morphologic and functional evaluations of pulmonary nodules.

Relationship between quantitative CT of pulmonary small vessels and pulmonary perfusion.

OBJECTIVE: The relationship between morphologic alterations of pulmonary small vessels and pulmonary perfusion has not been clarified. The purpose of this study was to evaluate the relationship between the cross-sectional area (CSA) of pulmonary small vessels alterations measured on CT images and pulmonary perfusion on lung perfusion scintigraphy. MATERIALS AND METHODS: This study comprised 46 subjects who underwent both CT and lung perfusion scintigraphy. We measured CSA of pulmonary small vessels less than 5 mm(2) and 5-10 mm(2) using CT images and obtained the percentage of the right lung to whole lung in each CSA group (CSA<5,R/W and CSA5-10,R/W, respectively). Using (99m)Tc-macroaggregated albumin (MAA) lung perfusion scintigraphy, we obtained right and total lung counts and calculated the percentage of the right to whole-lung counts (MAAR/W). Those CT and scintigraphy measurements were also calculated separately each in right upper, right lower, left upper, and left lower zones. The correlations of CSA<5,R/W and CSA5-10,R/W with MAAR/W, the correlation between the percentage of each lung zone to whole-lung CSA<5 and the percentage of each corresponding lung zone to whole-lung MAA were evaluated. RESULTS: The mean CSA<5,R/W was 58.1% ± 11.2%, and the mean MAAR/W was 59.3% ± 17.9%. CSA<5,R/W had a significant correlation with MAAR/W (ρ = 0.865, p < 0.0001), whereas significant correlation was found but was relatively weak between CSA5-10,R/W and MAAR/W (ρ = 0.512, p = 0.0003). The percentage of each lung zone to whole-lung CSA<5 had significant correlations with the percentage of each corresponding lung zone to whole-lung MAA. CONCLUSION: Pulmonary small vessels alteration, as measured by CSA on CT images, significantly correlated with pulmonary perfusion.

Quantitative computed tomography assessment of air trapping in relapsing polychondritis: correlations with spirometric values.

OBJECTIVE: The purpose of this study was to evaluate the relationship between quantitative computed tomography (CT) parameters of air trapping obtained with inspiratory and expiratory CT and pulmonary function tests (PFTs) in patients with relapsing polychondritis (RP). MATERIALS AND METHODS: This study included 23 patients with RP who underwent both CT and PFTs. In each patient, the mean lung density (MLD) was obtained by averaging CT attenuation of the lung parenchyma on both inspiratory and expiratory CT. The ratio of expiratory MLD to inspiratory MLD (E/I ratio) was also calculated. Correlations between those quantitative CT measurements and the results of PFTs were evaluated using Spearman rank correlation. RESULTS: The expiratory MLD and E/I ratio were significantly correlated with forced expiratory volume in 1 second (FEV1) %predicted, ratio of FEV1 to FVC (FEV1/FVC), and the mid expiratory phase of forced expiratory flow (FEF25%-75%) %predicted (expiratory MLD: FEV1 %predicted, r = 0.764, P < 0.0001; FEV1/FVC, r = 0.764, P < 0.0001; FEF25%-75% %predicted, r = 0.674, P < 0.001, respectively; the E/I ratio: FEV1 %predicted, r = -0.689, P < 0.001; FEV1/FVC, r = -0.689, P < 0.001; FEF25%-75% %predicted, r = -0.586, P < 0.01, respectively). The correlation between inspiratory MLD and PFTs did not reach statistical significance. CONCLUSIONS: In RP patients, air trapping demonstrated on expiratory CT correlated with airway obstruction. This study may assist further refinement of the use of CT as quantitative evaluation for small and large airway obstruction in RP.

Effects of bronchodilators on regional lung sound distribution in patients with chronic obstructive pulmonary disease.

BACKGROUND: Bronchodilators have been reported to influence regional lung ventilation in patients with chronic obstructive pulmonary disease (COPD), which may change regional lung sound distribution. Vibration response imaging (VRI) is a lung imaging system for the assessment of breath sounds. OBJECTIVE: To evaluate the effects of a short-acting ß2-agonist (SABA) on the regional distribution of lung sounds in COPD patients. METHODS: A double-blind crossover trial was performed to compare the treatment of COPD patients with an SABA (20 µg of inhaled procaterol) versus a placebo. The percentage of regional lung sound energy [quantitative lung data (QLD)] was evaluated with VRI. VRI, spirometry, and impulse oscillometry (IOS) were performed immediately before and 30 min after SABA administration. RESULTS: Ten male patients (69.6 ± 14.2 years of age, percentage predicted forced expiratory volume in 1 s: 43.8 ± 16.9%) were evaluated. The use of an SABA produced significant functional improvements in the spirometric and IOS measurements. Among the homogeneous emphysema patients (n = 7), the upper-lung QLD decreased (from 24.2 ± 5.8 to 18.8 ± 6.1%, p < 0.05) and the lower-lung QLD increased (from 37.9 ± 12.7 to 46.1 ± 14.3%, p < 0.05) following SABA inhalation. However, the significant redistribution of the regional lung QLD to the lower-lung field was not observed in 2 of the 3 inhomogeneous emphysema patients. CONCLUSION: The additional use of an SABA by COPD patients improved their pulmonary function, which was accompanied by changes in regional lung air flow. The distribution of emphysematous lesions and the bronchial reactivity to SABA appeared to affect the redistribution of the lung sounds following bronchodilator administration.

Selective Angiographic Evaluation in Patients with Simple-Type Pulmonary Arteriovenous Malformations Treated with Vascular Plug.

PURPOSE: To evaluate the angiographic recanalization rate of patients who underwent embolization juxta-proximal to the sac with AMPLATZER Vascular Plug type IV (AVP IV) for a simple pulmonary arteriovenous malformation (PAVM). MATERIAL AND METHODS: Ten patients (7 females and 3 males; median age, 47 years [range 28-83 years]) with 19 simple-type PAVMs who underwent embolization using an AVP IV between May 2015 and November 2021 were included in this retrospective study. The median feeding artery diameter on computed tomography was 4.0 mm (range 3-5.9 mm), and the median ratio of AVP IV size to feeding artery diameter on computed tomography was 1.5 (range 1.3-2.1). Technical success was defined by AVP IV placement at the junction between the pulmonary artery and the sac, or the pulmonary artery within 1 cm from the junction and beyond the last normal branch. The primary endpoint was the PAVM recanalization rate in selective or segmental pulmonary angiography performed 1 year post-embolization. RESULTS: The technical success rate of embolization juxta-proximal to the sac for simple-type PAVMs was 100%. None of the 19 lesions showed recanalization in pulmonary angiography performed 1 year after embolization. One patient experienced hemoptysis and pneumonia. CONCLUSION: Embolization of simple-type PAVMs' feeding vessel using AVP IV is safe and effective, with a high technical success rate and no recanalization on pulmonary angiography performed at 1 year post-embolization.

Helicity Induction in Three π-Conjugated Chromophores by Planar Chirality of Calixamide.

Shall we twist? Three-dimensional arrangement of π-conjugated chromophores with triple-stranded helicity was achieved by using the planar chirality of m-calix[3]amide. Based on spectroscopic data and theoretical calculations, the dynamic and preferred helical characters of bithiophene units embedded in the tubular molecule were elucidated, and the absolute configuration was determined.

Experimental mechanistic studies of the tail-to-tail dimerization of methyl methacrylate catalyzed by N-heterocyclic carbene.

We and others have previously reported the intermolecular umpolung reactions of Michael acceptors catalyzed by an N-heterocyclic carbene (NHC). The representative tail-to-tail dimerization of methyl methacrylate (MMA) has now been intensively investigated, leading to the following conclusions: (1) The catalysis involves the deoxy-Breslow intermediate, which is quite stable and remains active after the catalysis. (2) Addition of the intermediate to MMA and the final catalyst elimination are the rate-limiting steps. Addition of the NHC to MMA and the proton transfers are relatively very rapid. (3) The two alkenyl protons of the first MMA undergo an intermolecular transfer to C3 and C5 of the dimer. (4) The initial proton transfer is intermolecular. (5) Compared with the benzoin condensation, noticeable differences in the kinetics, reversibility, and stability of the intermediates are observed.

Assessing the site of maximal obstruction in the trachea using lateral pressure measurement during bronchoscopy.

RATIONALE: Lateral airway pressure can provide valuable physiological information during bronchoscopy. OBJECTIVES: To evaluate tracheal obstruction during intervention. METHODS: To prospectively measure lateral airway pressure during bronchoscopy using a double-lumen catheter in 15 healthy subjects and 30 patients with tracheal obstruction. Pressure difference was used to evaluate the site of maximal obstruction. The angle between pressure recordings on either side of the stenosis was measured simultaneously (pressure-pressure curves) to assess the degree of tracheal obstruction. MEASUREMENTS AND MAIN RESULTS: In the experimental study, the angle of the pressure-pressure curve was unaffected by breathing maneuvers whereas the pressure difference was affected. In healthy subjects, no pressure difference between the carina and trachea was observed during tidal breathing, and the angle was close to 45°. In patients with tracheal obstruction, the dyspnea scale, pressure difference, and angle changed significantly beyond 50% obstruction (P<0.0001). After stenting, the pressure difference disappeared and the angle was close to 45°. The degree of tracheal obstruction was significantly correlated with the pressure difference (r=0.83, P<0.0001) and angle (r=-0.84, P<0.0001). The cross-sectional area, dyspnea scale, pulmonary function tests, pressure difference, and the angle significantly improved after procedures (P<0.0001). Responder rates on the modified Medical Research Council Scale were 84.6% for obstructions above 80%, and 58.8% for obstructions between 50 and 80%. CONCLUSIONS: The direct measurement of pressure difference and the angle of the pressure-pressure curve represent a new assessment modality for the success of interventional bronchoscopy. Measuring lateral airway pressure could estimate the need for additional procedures better than bronchoscopy alone.

Long-term survival, causes of death, and prognostic factors for mortality in patients with microscopic polyangiitis and those with anti-neutrophil cytoplasmic antibody-positive interstitial lung disease: A single-center retrospective study.

AIM: To elucidate the clinical features, long-term survival, and prognostic factors for mortality among patients with microscopic polyangiitis (MPA), including those with anti-neutrophil cytoplasmic antibody-positive interstitial lung disease (ILD) (ANCA-ILD), which could be a subset of its variant phenotype. METHODS: We retrospectively included 76 consecutive patients between 2006 and 2014, diagnosed with MPA according to the European Medicines Agency algorithm using the Chapel Hill Consensus Conference definitions or ANCA-ILD. ILD was classified as usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia pattern using chest computed tomography. RESULTS: The mean (standard deviation) age of the patients (female, 68%) was 69 (12) years. The median (interquartile range) follow-up period was 68 (33-95) months. Comorbid ILD and glomerulonephritis were observed in 44 (58%) (68% UIP) and 54 (71%) patients, respectively. Comorbid ILD was associated with low survival (P = .0563). There were 17 (39%) and 5 (16%) deaths in the ILD and non-ILD groups, respectively (P = .0404). In the ILD group, 6 and 5 of the deaths were attributed to infection and ILD progression, respectively. In the non-ILD group, 1 and 2 patients expired from subsequently developed ILD and aspiration pneumonia, respectively. Age ≥ 70 years (hazard ratio = 2.78; 95% confidential interval 1.15-6.70) and UIP (3.95; 1.60-9.77) were independent risk factors for mortality. CONCLUSION: Age ≥ 70 years and ILD with a UIP pattern were associated with high mortality, owing to susceptibility to infection and ILD progression. A more effective and less toxic treatment is required for progressive ILD.