The impact of COPD on polyneuropathy: results from the German COPD cohort COSYCONET

Background

Peripheral neuropathy is a common comorbidity in COPD. We aimed to investigate associations between alterations commonly found in COPD and peripheral neuropathy, with particular emphasize on the distinction between direct and indirect effects.

Methods

We used visit 4 data of the COPD cohort COSYCONET, which included indicators of polyneuropathy (repeated tuning fork and monofilament testing), excluding patients with diabetes a/o increased HbA1c. These indicators were analysed for the association with COPD characteristics, including lung function, blood gases, 6-min walk distance (6-MWD), timed-up-and-go-test (TUG), exacerbation risk according to GOLD, C-reactive protein (CRP), and ankle-brachial index (ABI). Based on the results of conventional regression analyses adjusted for age, BMI, packyears and gender, we utilized structural equation modelling (SEM) to quantify the network of direct and indirect relationships between parameters.

Results

606 patients were eligible for analysis. The indices of polyneuropathy were highly correlated with each other and related to base excess (BE), ABI and TUG. ABI was linked to neuropathy and 6-MWD, exacerbations depended on FEV₁, 6-MWD and CRP. The associations could be summarized into a SEM comprising polyneuropathy as a latent variable (PNP) with three measured indicator variables. Importantly, PNP was directly dependent on ABI and particularly on BE. When also including patients with diabetes and/or elevated values of HbA1c (n = 742) the SEM remained virtually the same.

Conclusion

We identified BE and ABI as major determinants of peripheral neuropathy in patients with COPD. All other associations, particularly those with lung function and physical capacity, were indirect. These findings underline the importance of alterations of the micromilieu in COPD, in particular the degree of metabolic compensation and vascular status.

Left heart function in COPD : Impact of lung deflation

Chronic obstructive pulmonary disease (COPD) primarily affects the lungs; however, cardiovascular conditions are among the most common extrapulmonary comorbidities. Besides shared risk factors such as cigarette smoking, pathophysiological connections between the lung and the heart have been identified as mediators of reduced cardiac output. Recent research has focused on hyperinflation of the lung as a pulmonary cause for heart dysfunction. Hyperinflation is a typical lung abnormality seen in COPD; it is characterized by increased residual volume, intrathoracic gas volume, and total lung capacity while vital capacity is decreased. The degree of hyperinflation with airway obstruction is inversely related to left ventricular filling, stroke volume, and cardiac output. The underlying mechanisms are assumed to be compression of the pulmonary veins and thus reduced preload of the left heart as well as decreased pulmonary microvascular blood flow due to compression of the pulmonary vasculature. Treatment with a dual bronchodilator antagonizes this detrimental lung-heart unbalance effectively: Pulmonary blood flow, left ventricular end-diastolic volume, and stroke volume increase in COPD patients without cardiac abnormalities. Similar effects, yet less pronounced, were reported with single bronchodilator therapy. Future work needs to investigate whether these promising findings can be reproduced in COPD patients with cardiovascular diseases.

Combined effects of lung function, blood gases and kidney function on the exacerbation risk in stable COPD: Results from the COSYCONET cohort

RATIONALE

Alterations of acid-base metabolism are an important outcome predictor in acute exacerbations of COPD, whereas sufficient metabolic compensation and adequate renal function are associated with decreased mortality. In stable COPD there is, however, only limited information on the combined role of acid-base balance, blood gases, renal and respiratory function on exacerbation risk grading.

METHODS

We used baseline data of the COPD cohort COSYCONET, applying linear and logistic regression analyses, the results of which were implemented into a comprehensive structural equation model. As most informative parameters it comprised the estimated glomerular filtration rate (eGFR), lung function defined via forced expiratory volume in 1 s (FEV₁), intrathoracic gas volume (ITGV) and (diffusing capacity for carbon monoxide (DLCO), moreover arterial oxygen content (CaO₂), partial pressure of oxygen (PaCO₂), base exess (BE) and exacerbation risk according to GOLD criteria. All measures were adjusted for age, gender, body-mass index, the current smoking status and pack years.

RESULTS

1506 patients with stable COPD (GOLD grade 1-4; mean age 64.5 ± 8.1 y; mean FEV₁ 54 ± 18 %predicted, mean eGFR 82.3 ± 16.9 mL/min/1.73 m²) were included. BE was linked to eGFR, lung function and PaCO₂ and played a role as indirect predictor of exacerbation risk via these measures; moreover, eGFR was directly linked to exacerbation risk. These associations remained significant after taking into account medication (diuretics, oral and inhaled corticosteroids), whereby corticosteroids had effects on exacerbation risk and lung function, diuretics on eGFR, BE and lung function.

CONCLUSION

Even in stable COPD acid-base metabolism plays a key integrative role in COPD risk assessment despite rather small deviations from normality. It partially mediates the effects of impairments in kidney function, which are also directly linked to exacerbation risk.

[Presumed consent for organ donation? : A survey among members of the German Society of Medical Intensive Care and Emergency Medicine]

BACKGROUND

Since 2010, the number of organ donations has decreased by 30% in Germany; however, stricter organizational structures in clinics and improved payment for hospital services associated with organ removal should increase the current decline in the number of organ donations in Germany. In addition, the Federal Minister of Health proposed introduction of the double presumed consent solution for organ donation. This proposal is currently being discussed very controversially. Against this background, we conducted an online survey of all members of the German Society of Medical Intensive Care and Emergency Medicine (DGIIN) in order to evaluate the attitude towards organ donation.

METHOD

The present work is an anonymous online survey among the members of DGIIN, which took place from 10-23 September 2018. In addition to a few demographic queries, the personal opinion on the regulation of organ donation was collected.

RESULTS

A total of 1019 (51.9%) of 1964 invited DGIIN members took part at the survey: 79.3% of the participants were male; average age 47.5 ± 11.2 years; 97.7% were physicians, of whom 89.2% were specialists and 62.7% had the additional degree in critical care; 20.6% voted for the current decision-making solution, 43.1% for the presumed consent, 33.1% for the double presumed consent, whereas 3.2% of the respondents were uncertain in their decision.

CONCLUSION

A clear majority of the surveyed members of DGIIN support the concept of presumed consent.

Blood monocyte profiles in COPD patients with PiMM and PiZZ α1-antitrypsin

Human blood monocytes are divided into populations based on the differential expression of CD14 and CD16 receptors: CD14 ⁺ CD16(classical), CD14 ⁺ CD16 ⁺ (intermediate), and CD14^-CD16⁺ (non-classical). Given their functional differences and their role in pathogenesis of chronic obstructive pulmonary disease (COPD), monocyte profiling is of clinical interest. Here we investigated blood monocyte subsets in clinically stable COPD patients with alpha1-antitrypsin (AAT) deficiency (PiZZ, n = 7) and with normal AAT variant (PiMM, n = 7). Peripheral whole blood was collected in sodium heparin tubes and incubated with LPS (from E. coli; 1 μg/ml) or placebo for 6 h at 37 °C, 5% CO2. To profile monocyte subsets we performed flow cytometry analysis based on HLA-DR and CD14/CD16 staining. HLA-DR + subsets of cells did not differ between PiZZ and PiMM COPD, and healthy controls (n = 7), used as a reference. Monocyte profiling, which express the CD14 and CD16, but not the HLA-DR (HLA-DR-) showed that intermediate monocytes subset was lowest in PiZZ group, and almost totally disappeared from blood treated with LPS. The non-classical subset was almost absent in PiZZ patients independently of LPS treatment. Recent studies demonstrate that non-classical monocytes exhibit a unique ability to protect the vascular endothelium under both homeostatic and inflammatory conditions whereas intermediate monocytes are recruited at a later stage of inflammation, and are associated with secretion of cytokines/chemokines and wound healing. Evident alterations in blood monocyte subsets together with a partial reduction of AAT levels, an important anti-inflammatory protein, can be key factors for the early manifestation of emphysema in some PiZZ AATD carriers.

[Pneumological Assessment with Regard to Performance Demands - Concept: "Load to Capacity"]

Professional opinions on and assessments of physical performance must be oriented to the individual capacity of the person in question. Moreover, this performance has to be correlated with the expected physical load at work, sports activities or operative stress. This "Load to Capacity Concept" is already a part of an integrative medical assessment, based on clinical experience and common sense, rather than on diagnostic numerical values. An evaluation of work intensity in the context of socio-medical assessment ("light - moderate - severe - very severe", German Statutory Pension Insurance, based on the German REFAClassification) can now be complemented by well accessible and valid data based on measurements of real-life and professional activities. Also the ratio of continuous power in view of the maximal power output (V'O₂ peak) and the power at the aerobic-anaerobic threshold (V'O₂ at VT1) is well established. This information is gained by ergospirometry (CPET - Cardio Pulmonary Exercise Testing). The focus while interpreting the performance lies on Watt as a physical parameter and on O₂-consumption (V'O₂ L/min) as the crucial biological correlate. V'O₂ is presented as a direct value (L/min) or in complex values like MET (Metabolic Equivalent of Task) and calories (kcal).Recent studies can take advantage of technical progress in this field: rapid sensory measurement, convenient display in graphs and tables. In earlier literature there is ample information on working demands and energy expenditure, supplemented by V'O₂-data and MET (see Ainsworth et al.). These studies are helpful for orientation. However, it has to be kept in mind that these studies were done with technical possibilities available then, mostly in a laboratory setting, not under real-life conditions. Portable ergospirometry was not available at that time. Ergospirometry has already proved to be a useful tool in cases where expert opinion is required on compensation claims or questions of early retirement. Positive results of our study on "Occupational Activity of Cleaning Personnel in Clinics" are also reported here.

Detection of chronic lung allograft dysfunction using ventilation-weighted Fourier decomposition MRI

Chronic lung allograft dysfunction (CLAD) remains the leading cause of morbidity and mortality after lung transplantation. Diagnosis requires spirometric change, which becomes increasingly difficult with advancing CLAD. Fourier decomposition magnetic resonance imaging (FD-MRI) permits acquisition of ventilated-weighted images during free-breathing. This study evaluates FD-MRI in detecting CLAD in selected patients after bilateral lung transplantation (DLTx). DLTx recipients demonstrating CLAD at various stages participated. Radiologists remained blinded to clinical status until completion of image analysis. Image acquisition used a 1.5-T MR scanner using a spoiled gradient echo sequence. After FD processing and regional fractional ventilation (RFV) quantification, the volume defect percentage at 2 thresholds (VDP_1,2 ), median lung RFV and quartile coefficient of dispersion (QCD) were calculated. Sixty-two patients participated. CLAD was present in 29/62 (47%) patients, of whom 17/62 (27%) had forced expiratory volume in 1 second ≤65% at image acquisition. VDP₁ was higher among these participants compared to other groups (P < .001). Increased VDP₁ was associated with subsequent graft loss, with values >2% showing reduced survival, independent of degree of graft dysfunction (P = .005). VDP₂ discriminated between presence or absence of CLAD (area under the curve = 0.71; P = .03). QCD increased significantly with advancing disease (P < .001). In conclusion, FD-MRI-derived parameters demonstrate potential in quantitative CLAD diagnosis and assessment after DLTx.

Lobe-wise assessment of lung volume and density distribution in lung transplant patients and value for early detection of bronchiolitis obliterans syndrome

PURPOSE

To evaluate quantitative computed tomography (CT) measurements of the lung parenchyma in lung transplant (LTx) patients for early detection of the bronchiolitis obliterans syndrome (BOS).

MATERIALS AND METHODS

359 CT scans of 122 lung transplant patients were evaluated. Measurements of lung volume and density were performed for the whole lung and separately for each lobe. For longitudinal analysis the difference between the baseline at 6 months after LTx and follow-up examinations was calculated. Patients with and without BOS (matched 1:2) were compared at two different time points, the last examination before the BOS onset and the first examination within one year after BOS onset.

RESULTS

30 patients developed BOS during the follow-up period. Longitudinal changes in the lung volume and lung density measured on CT differed significantly between those patients with and without early BOS, in particular the difference of the inspiratory and expiratory lung volume (p < 0.001), the ratio of the expiratory and inspiratory lung volume (p < 0.001-p = 0.001) and MLD (p < 0.001-p = 0.001), the volume on expiration (p < 0.001-p = 0.007), the MLD on expiration (p < 0.001-p = 0.007), and the percentiles on expiration (p < 0.001-p = 0.002) with an increase of lung volume and a decrease of lung density. Changes were pronounced in the lower lobes. Before BOS onset, patients with and without future development of BOS showed no significant differences.

CONCLUSION

Longitudinal changes of lung volume and lung density measured on CT start markedly at BOS onset with increased lung volume and decreased lung density indicating increased inflation levels. Even though this method may help to diagnose BOS at onset it is not useful as a predictor for BOS before disease onset.

Endobronchial Ultrasound in Suspected Non-Malignant Mediastinal Lymphadenopathy

BACKGROUND

 Endobronchial ultrasound (EBUS) bronchoscopy with transbronchial needle aspiration (TBNA) is a well-established tool in mediastinal staging in lung cancer and gains importance in exploration of non-malignant lymphadenopathy. The aim of this study was to evaluate the role of EBUS-TBNA in suspected non-malignant diseases.

METHODS

 A retrospective, single-center, observation analysis of endobronchial ultrasound bronchoscopy procedures was performed in a university medical center between March 2013 and July 2015. All patients with suspected non-malignant mediastinal lymphadenopathy were included. Cytopathological and microbiological results of EBUS were compared to clinical diagnosis 6 months after procedure and performance of EBUS was contrasted to malignant indications.

RESULTS

 During study period, 333 EBUS bronchoscopies in 315 patients with mediastinal lymphadenopathy were performed. 111 out of 315 (35 %) patients had neither primary signs nor history of a malignant disease, categorised as patients with suspected non-malignant disease. 245 lymph nodes were sampled (median size 15 mm [IQR10 - 19]). Preferred station for TBNA was lymph node station 7 (38 %). Cytopathological findings revealed non-specific inflammation (n = 81; 70 %), carcinoma (n = 7; 6 %), epithelioid cell granulomas (n = 20; 17 %). 7 samples (6 %) were non-representative. Microbiologic testing of lymph nodes identified 3 infections (Mycobacteria tuberculosis [n = 2] and Nocardia nova [n = 1]) relevant to antibiotic therapy. Minor adverse events were observed in 9 out of 115 (8 %) patients. Sensitivity of EBUS-TBNA intervention in suspected non-malignant disease was 76 % and specificity 96 %.

CONCLUSIONS

 EBUS-TBNA revealed a specific cause for suspected non-malignant lymphadenopathy in one-third of cases and was associated with excellent specificity. Predominant specific causes were granuloma, besides from tumor. In 3 patients pathogen could be isolated by TBNA.

[Guideline for the Diagnosis and Treatment of COPD Patients - Issued by the German Respiratory Society and the German Atemwegsliga in Cooperation with the Austrian Society of Pneumology]

This document is a revision of the guideline for diagnosis and treatment of COPD that replaces the version from 2007. A multitude of recent reports regarding risk factors, diagnosis, assessment, prevention and pharmacological as well as non-pharmacological treatment options made a major revision mandatory. The new guideline is based on the GOLD document taking into account specifics in Germany and Austria.