COPD-associated pulmonary hypertension: clinical implications and current methods for treatment

Clinical characteristics and predictors of pulmonary hypertension in chronic obstructive pulmonary disease at different altitudes

BACKGROUND

Pulmonary hypertension (PH) is a common complication in patients with chronic obstructive pulmonary disease (COPD) and is closely associated with poor prognosis. However, studies on the predictors of PH in COPD patients are limited, especially in populations living at high altitude (HA).

OBJECTIVES

To investigate the differences in the clinical characteristics and predictors of patients with COPD/COPD and PH (COPD-PH) from low altitude (LA, 600 m) and HA (2200 m).

METHODS

We performed a cross-sectional survey of 228 COPD patients of Han nationality admitted to the respiratory department of Qinghai People's Hospital (N = 113) and West China Hospital of Sichuan University (N = 115) between March 2019 and June 2021. PH was defined as a pulmonary arterial systolic pressure (PASP) > 36 mmHg measured using transthoracic echocardiography (TTE).

RESULTS

The proportion of PH in COPD patients living at HA was higher than that in patients living at LA (60.2% vs. 31.3%). COPD-PH patients from HA showed significantly different in baseline characteristics, laboratory tests and pulmonary function test. Multivariate logistic regression analysis indicated that the predictors of PH in COPD patients were different between the HA and LA groups.

CONCLUSIONS

The COPD patients living at HA had a higher proportion of PH than those living at LA. At LA, increased B-type natriuretic peptide (BNP) and direct bilirubin (DB) were predictors for PH in COPD patients. However, at HA, increased DB was a predictor of PH in COPD patients.

Prediction of long-term mortality by using machine learning models in Chinese patients with connective tissue disease-associated interstitial lung disease

Background

The exact risk assessment is crucial for the management of connective tissue disease-associated interstitial lung disease (CTD-ILD) patients. In the present study, we develop a nomogram to predict 3‑ and 5-year mortality by using machine learning approach and test the ILD-GAP model in Chinese CTD-ILD patients.

Methods

CTD-ILD patients who were diagnosed and treated at the First Affiliated Hospital of Zhengzhou University were enrolled based on a prior well-designed criterion between February 2011 and July 2018. Cox regression with the least absolute shrinkage and selection operator (LASSO) was used to screen out the predictors and generate a nomogram. Internal validation was performed using bootstrap resampling. Then, the nomogram and ILD-GAP model were assessed via likelihood ratio testing, Harrell’s C index, integrated discrimination improvement (IDI), the net reclassification improvement (NRI) and decision curve analysis.

Results

A total of 675 consecutive CTD-ILD patients were enrolled in this study, during the median follow-up period of 50 (interquartile range, 38–65) months, 158 patients died (mortality rate 23.4%). After feature selection, 9 variables were identified: age, rheumatoid arthritis, lung diffusing capacity for carbon monoxide, right ventricular diameter, right atrial area, honeycombing, immunosuppressive agents, aspartate transaminase and albumin. A predictive nomogram was generated by integrating these variables, which provided better mortality estimates than ILD-GAP model based on the likelihood ratio testing, Harrell’s C index (0.767 and 0.652 respectively) and calibration plots. Application of the nomogram resulted in an improved IDI (3- and 5-year, 0.137 and 0.136 respectively) and NRI (3- and 5-year, 0.294 and 0.325 respectively) compared with ILD-GAP model. In addition, the nomogram was more clinically useful revealed by decision curve analysis.

Conclusions

The results from our study prove that the ILD-GAP model may exhibit an inapplicable role in predicting mortality risk in Chinese CTD-ILD patients. The nomogram we developed performed well in predicting 3‑ and 5-year mortality risk of Chinese CTD-ILD patients, but further studies and external validation will be required to determine the clinical usefulness of the nomogram.

Co-existing obstructive sleep apnea among patients with chronic obstructive pulmonary disease

Background and Objectives:

Chronic obstructive pulmonary disease (COPD) is a common airway disease that is frequently associated with comorbidities. In this study, we assessed the co-existence of obstructive sleep apnea (OSA) among patients with stable COPD.

Methodology:

This cross-sectional study included patients with stable COPD who were screened with Epworth's Sleepiness Scale (ESS). Those with ESS score of >10 were subjected to in-lab polysomnography (PSG). PSG was manually analyzed and reported. Patients with apnea–hypopnea index of >5/h were diagnosed as OSA.

Results:

This study included 301 patients (78.1% male, 76.4% smokers, age 59.6 ± 10 years) with stable COPD. ESS score of >10 was observed in 47 (15.6%) patients. Among patients with ESS score of >10, OSA was observed in 34 (72.3%) patients. The overall prevalence of OSA among patients with COPD was 10.9%. Patients with co-existing OSA were older and had thicker neck and higher body mass index (BMI) as compared to COPD alone. In addition, patients with associated OSA had worse health-related quality of life (QOL) as shown by higher St. George's Respiratory Questionnaire score (42.42 ± 7.22 vs. 25.22 ± 8.66; P < 0.001).

Conclusions:

Co-existing OSA is common among patients with COPD and has a significant adverse effect on the QOL. Among COPD patients, older age, thick neck, and high BMI may predict co-existing OSA and require PSG for the confirmation.

Hypoxic mast cells accelerate the proliferation, collagen accumulation and phenotypic alteration of human lung fibroblasts

Pulmonary vascular remodeling and fibrosis are the critical pathological characteristics of hypoxic pulmonary hypertension. Our previous study demonstrated that hypoxia is involved in the functional alteration of lung fibroblasts, but the underlying mechanism has yet to be fully elucidated. The aim of the present study was to investigate the effect of mast cells on the proliferation, function and phenotype of fibroblasts under hypoxic conditions. Hypoxia facilitated proliferation and the secretion of proinflammatory cytokines, including tumor necrosis factor (TNF)‑α and interleukin (IL)‑6, in human mast cells (HMC‑1). RNA sequencing identified 2,077 upregulated and 2,418 downregulated mRNAs in human fetal lung fibroblasts (HFL‑1) cultured in hypoxic conditioned medium from HMC‑1 cells compared with normoxic controls, which are involved in various pathways, including extracellular matrix organization, cell proliferation and migration. Conditioned medium from hypoxic HMC‑1 cells increased the proliferation and migration capacity of HFL‑1 and triggered phenotypic transition from fibroblasts to myofibroblasts. A greater accumulation of collagen type I and III was also observed in an HFL‑1 cell culture in hypoxic conditioned medium from HMC‑1 cells, compared with HFL‑1 cells cultured in normoxic control medium. The expression of matrix metalloproteinase (MMP)‑9 and MMP‑13 was upregulated in HFL‑1 cells grown in hypoxic conditioned medium from HMC‑1 cells. Similar pathological phenomena, including accumulation of mast cells, activated collagen metabolism and vascular remodeling, were observed in a hypoxic rat model. The results of the present study provide direct evidence that the multiple effects of the hypoxic microenvironment and mast cells on fibroblasts contribute to pulmonary vascular remodeling, and this process appears to be among the most important mechanisms underlying hypoxic pulmonary hypertension.

Prognostic significance of pulmonary hypertension in patients with cystic fibrosis: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Pulmonary hypertension (PH) is frequently found in advanced parenchymal lung diseases like cystic fibrosis (CF), but the role played by PH in the clinical outcome of CF patients remains unclear. The aim of this study is to determine the influence of PH on survival in the CF population by meta-analysis.

METHODS

Publications addressing the associations between PH and overall survival (OS) or other clinical characteristics in CF patients were selected from electronic databases. Odds ratios (ORs) or mean differences (MDs) were used to estimate the association between PH and the clinical characteristics. The hazard ratios (HRs) with 95% confidence interval (CI) were abstracted or calculated to evaluate the association between PH and CF survival outcome. Subgroup analyses were also conducted.

RESULTS

Seven studies including 2141 CF patients who met the inclusion criteria were included in our meta-analysis. With respect to clinical features, PH was significantly associated with lower PaO2 (P < .001), higher PaCO2 (P = .02), lower forced expiratory volume in 1 second percent (P < .001) and lower forced vital capacity percent (P < .001). However, PH had no significant impact on CF patients' OS (HR = 1.29, 95% CI 0.81 to 2.06, P = .283). Furthermore, subgroup analyses also showed no evidence of prognostic role of PH in CF patients (all P values >.05).

CONCLUSIONS

Our findings suggest that the presence of PH was strongly correlated with worse blood-gas parameters and worse lung function, but surprisingly had no significant prognostic value on survival among CF patients. Further large-scale and prospective studies are needed to confirm these findings.