Prevalence and outcomes of pulmonary arterial hypertension in advanced idiopathic pulmonary fibrosis

Post lung-transplant predictive value of thermodilution vs estimated Fick cardiac output measurement

Background

Comparison of thermodilution (TD) and indirect Fick (iFick) methods of cardiac output (CO) measurement has not been well described in patients with World Health Organization (WHO) group 3 pulmonary hypertension (PH).

Methods

We conducted a single-center retrospective chart review of 96 patients with WHO group 3 PH who underwent lung transplantation. For comparison, 32 WHO group 1 pulmonary arterial hypertension patients who were followed in our PH clinic during the same period were also included in the study.

Results

TThere was a significant difference between iFick CO and TD CO (5.93+/ -1.5 versus 5.46+/ -1.8 liter/minute, p=0.0061) in WHO group 3 PH. Pulmonary vascular resistance (PVR) calculated using iFick and TD-CO values also differed significantly. TD-PVR was more strongly associated with measures of poor outcomes after lung transplant.

Conclusions

iFick-CO and TD-CO can be significantly different in WHO group 3 PH. In cases of discrepancy between iFick and TD-COs, TD-CO correlates better with clinical outcomes after lung transplantation.

The clinical impact of acute vasoreactivity testing in patients with severe pulmonary hypertension associated with lung disease: A retrospective exploratory analysis

BACKGROUND

The clinical impact of acute vasoreactivity testing with inhaled nitric oxide (NO testing) in severe pulmonary hypertension associated with lung disease (LD-PH) remains unknown.

METHODS

We retrospectively reviewed 48 consecutive patients with severe LD-PH (73 ± 9 years; male: 81%) who underwent NO testing between 2014 and 2022. We conducted an exploratory analysis of the association between the response to NO testing and both the efficacy of pulmonary vasodilators and prognosis.

RESULTS

NO testing demonstrated a significant improvement in hemodynamics, with an average reduction of 1.8 wood units in pulmonary vascular resistance (PVR) without a decrease of oxygen saturation. Patients were divided into the vasoreactive and non-vasoreactive groups based on the median PVR response (-15%) to NO testing. The vasoreactive group had a higher proportion of patients who initiated pulmonary vasodilators and had better long-term prognosis than that of the non-vasoreactive group (P = 0.03). Among the 36 patients (75%) who initiated pulmonary vasodilators after NO testing, the vasoreactive group demonstrated a significant improvement in the symptom, brain natriuretic peptide level, and hemodynamics at the first follow-up (median 4 months), whereas the non-vasoreactive group did not. Moreover, a correlation was observed between the change in PVR at NO testing and the change in PVR after initiation of pulmonary vasodilators (r = 0.42, P = 0.02).

CONCLUSIONS

The PVR response to NO testing associated with short-term efficacy of pulmonary vasodilators in patients with severe LD-PH. Prospective studies of PVR response to NO testing on the clinical efficacy in large-scale LD-PH cohorts are warranted.

The global burden of heart failure attributable to interstitial lung diseases: insights from the global burden of disease study 2021

BACKGROUND

The burden of interstitial lung disease (ILD)-associated heart failure (HF) poses a significant challenge to the prognosis of ILD patients. This study aimed to characterize the disease burden and analyse future trends of ILD-associated HF, offering valuable insights to inform targeted prevention and control strategies.

METHODS

Data on the prevalence and years lived with disability (YLDs) of ILD-associated HF were retrieved from the Global Burden of Disease (GBD) database for the period 1990-2021. Trends in ILD-associated HF were evaluated using average annual percentage change (AAPC) and percentage change analyses. Future prevalence data were projected up to 2050 using predictive modelling.

RESULTS

Globally, the number of patients with ILD-associated HF increased from 20,229 in 1990 to 104,059 in 2021, with the prevalence rising from 0.53 to 1.41 per 100,000 population. Prevalence rates were disproportionately higher in older populations, with individuals over 95 years experiencing a 17.78-fold increase over the study period. Additionally, a positive correlation was observed between higher socioeconomic development index (SDI) levels and ILD-associated HF prevalence. Among 204 countries, 71.1% exhibited an increasing trend in prevalence. However, Bayesian age-period-cohort (BAPC) modelling predicts a declining trend over the next 28 years.

CONCLUSION

Over the past three decades, the global burden of ILD-associated HF has escalated, particularly among individuals aged over 65 and in regions with high SDI levels. These findings underscore the need for region-specific, personalized intervention strategies to mitigate disease progression and enhance the quality of life for ILD patients.

A Systematic Review and Expert Recommendation on the Diagnosis of Pulmonary Hypertension Associated With Lung Disease: A Position Paper of the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR)

Pulmonary hypertension (PH) is a common complication of chronic respiratory diseases (CRD) associated with increased morbidity and mortality. Early and individualized identification of PH in these patients is crucial to better understand the evolution of the disease and to assess the application of therapeutic measures aimed at its control. However, there is no consensus on how to approach the diagnostic process. The scarce scientific evidence in this field justifies the creation of this SEPAR position paper, which aims to become a tool to aid in the diagnosis of PH associated with CRD that facilitates decision making for the benefit of patients and the optimization of resources. A panel of 16 SEPAR experts has identified three critical questions. The answers to these questions were developed by the panel members, who were divided into three groups according to their expertise in the underlying disease in question: chronic obstructive pulmonary disease, interstitial lung disease and obesity hypoventilation syndrome. Prior to the discussion and drafting of the document by each group, a systematic review of the literature was performed according to the guidelines recommended by the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). We generated a schematic proposal adjusted to the characteristics of each disease for the diagnostic approach to PH associated with respiratory disease.

Review of the Diagnosis and Management of Pulmonary Hypertension Associated with Interstitial Lung Disease (ILD-PH)

Pulmonary hypertension associated with interstitial lung disease (ILD-PH) frequently complicates the course of patients with fibrotic ILD. In this narrative review, the authors assess current diagnostic tools and management considerations in ILD-PH patients. ILD-PH is associated with increased morbidity and mortality and may be suggested by the presence of symptoms out of proportion to the extent of the ILD. There are other clues to the presence of PH in the context of ILD including the need for supplemental oxygen, a reduced DLCO especially if accompanied by a disproportionately higher forced vital capacity, imaging demonstrating an enlarged pulmonary artery or a dilated right ventricle, or objective evidence of a reduced exercise capacity. While echocardiography is one screening tool, right heart catheterization remains the gold standard for the diagnosis of PH. When appropriate, treatment with inhaled treprostinil, or possibly other pulmonary vasodilators, may be indicated.

The Impact of Comorbidities on the Discontinuation of Antifibrotic Therapy in Patients with Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease of unknown aetiology. Evidence on the progression of idiopathic pulmonary fibrosis (IPF) following the introduction of antifibrotic therapies still indicates a generally poor prognosis. IPF is associated with both respiratory and non-respiratory comorbidities, which can worsen symptoms and impact overall survival. Background/Objectives: The study aimed to investigate the effect of these comorbidities on the early and permanent discontinuation of pirfenidone or nintedanib in IPF patients. Methods: In this single-centre retrospective study, 101 patients diagnosed with IPF according to ATS/ERS/JRS/ALAT guidelines were treated with AFT. Clinical data were collected at 12 months prior to and up to 24 months following treatment initiation, including age, gender, smoking history, and the presence of respiratory and non-respiratory comorbidities. Results: The data showed that 21 patients (20.8%) discontinued treatment within the first 12 months. Additionally, pre-treatment comorbidities were not statistically correlated with the suspension of antifibrotic treatment. Among the overall cohort, 77 patients (76.2%) had at least one comorbidity and 27 (26.7%) had three or more comorbidities. Notably, 24 (23.8%) had respiratory comorbidities, while 75 (74.3%) had non-respiratory comorbidities. Conclusions: This real-life study emphasises the complexities involved in managing IPF, particularly regarding adherence to treatment when significant comorbidities are present. The evidence suggests that in patients with IPF, pre-treatment respiratory or non-respiratory conditions do not affect AFT discontinuation.

Development of the pulmonary fibrosis, pulmonary vascular resistance, six minute walk distance, B-type natriuretic peptide, age (PVD-B65) risk score for patients with chronic lung disease and pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) confers increased mortality in patients with chronic lung disease, yet there remains a lack of validated risk assessment tools to prognosticate these patients. We aimed to create a risk assessment tool to stratify patients with chronic lung disease and PH by risk of one-year mortality from time of PH diagnosis.

METHODS

This was a retrospective cohort study of patients with chronic lung disease and PH. We identified predictors of one-year mortality via multivariable Cox regression and assigned point values to the identified predictors based on their hazard ratios to comprise the risk score. Patients were stratified into low, intermediate, and high-risk based on total scores. Kaplan-Meier survival analysis comparing the stratified groups was performed. Internal statistical validation was performed via Cox regression with bootstrapping.

RESULTS

The identified predictors of one-year mortality that comprised our risk assessment tool were pulmonary fibrosis without emphysema, pulmonary vascular resistance > 5 WU, six-minute walk distance < 150 m, BNP > 200 pg/mL, and age > 65 years (PVD-B65). Once patients were stratified into the three risk groups, Kaplan-Meier survival analysis demonstrated significant differences in one-year survival between the subgroups (logrank p = 0.002). The risk assessment model demonstrated internal validation via bootstrapping (p < 0.05).

CONCLUSION

The PVD-B65 risk assessment tool is a novel, internally validated one-year mortality risk calculator for patients with chronic lung disease and PH that encompasses factors related to pulmonary parenchymal and vascular remodeling. It may help risk stratify and guide therapeutic interventions in patients with chronic lung disease and PH.

Derivation of a simple risk calculator for predicting clinical worsening in patients with pulmonary hypertension due to interstitial lung disease

Background

Pulmonary hypertension due to interstitial lung disease (ILD-PH) portends very poor clinical outcomes, with a median survival time of 1.5 to 2 years. Currently, there is no tool to assess the risk of clinical worsening in patients with ILD-PH. Our aim was to derive a simple and practical risk calculator that could be used to predict risk of clinical worsening in patients with ILD-PH.

Methods

The INCREASE study was a 16-week study that evaluated inhaled treprostinil in patients with ILD-PH. Baseline data from patients who were randomized to the placebo arm (n=163) and thus untreated with any approved pulmonary artery vasodilators were used to derive a risk calculator. The endpoint of interest was the time to clinical worsening. Stepwise regression, Harrell's c-index, and clinician input were used to derive 2 multivariable Cox PH models from a set of candidate variables. The models were then simplified by applying a point-scoring system to the predictors and refitting with total point score as the covariate. Total point scores were grouped into 3 risk strata (lower, intermediate, and higher).

Results

Two versions of a risk calculator were derived. The first was a non-invasive risk calculator which included NT-proBNP and FVC%/DLCO%, and a second adds cardiac index, an invasive parameter, to the above two parameters. For the total point score models, the estimated c-indices were 0.703 (95% CI: 0.635, 0.783) and 0.683 (95% CI: 0.612, 0.761) for the invasive and non-invasive model, respectively.

Conclusion

These two risk calculators provide a simple way to risk stratify ILD-PH patients with clinically useful discrimination. The calculators are easy to employ in clinical practice, since they utilize assessments commonly collected in the care of patients with ILD-PH. Moreover, the calculators can provide clinicians with important prognostic information which can be used to reinforce the benefits of therapy. The risk calculators may also find utility as part of the composite allocation score of ILD-PH patients listed for lung transplant. Future research in this area could include incorporating longer-term outcomes as well as validating the risk models in a separate patient population.

CT Honeycombing and Traction Bronchiectasis Extent Independently Predict Survival across Fibrotic Interstitial Lung Disease Subtypes

Background Prognostic value of radiologic features in interstitial lung disease (ILD) has been predominantly studied in idiopathic pulmonary fibrosis, but findings vary. The relative importance of features versus guideline-defined patterns in predicting outcomes is unknown. Purpose To identify radiologic features that are independently associated with transplant-free survival beyond clinical predictive factors across all ILD subtypes, and to identify whether individual features versus patterns are more important for prognostication. Materials and Methods This is a secondary analysis of the prospective Canadian Registry for Pulmonary Fibrosis. Consecutive patients with ILD were evaluated in standardized multidisciplinary discussions between January 2021 and March 2022. Radiologic features on thin-section CT images were quantified, and guideline-defined usual interstitial pneumonia (UIP) and fibrotic hypersensitivity pneumonitis (fHP) patterns were assigned. Multivariable Cox analysis was used to assess the associations of radiologic features with transplant-free survival, and nested models were used to test the relative importance of features compared with patterns. Results A total of 1593 patients (mean age, 66 years ± 12 [SD]; 800 male) were included. The following four features were associated with transplant-free survival: extent of honeycombing (hazard ratio, 1.20; 95% CI; 1.06, 1.36 per 10% increase in lung involvement; P = .005), extent of traction bronchiectasis (hazard ratio, 1.18; 95% CI: 1.10, 1.26 per 10% increase; P < .001), pulmonary artery diameter (hazard ratio, 1.03; 95% CI: 1.01; 1.04 per 1-mm increase; P = .002), and presence of subpleural sparing (hazard ratio, 0.76; 95% CI: 0.56, 0.96; P = .03). Guideline-defined patterns were not independently associated with survival in a model that included these four radiologic features, each of which retained its prognostic value. Conclusion The extent of fibrosis was predictive of worse outcomes across all ILD subtypes in a dose-dependent fashion and independent of well-recognized clinical prognostic factors. Guideline-defined UIP and fHP patterns each helped risk-stratify patients in isolation but lost prognostic value when accounting for the extent of fibrosis, suggesting that their previous association with mortality is based on these patterns acting as surrogates for a greater extent of fibrosis. © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Wells in this issue.

Performance of the FORD Versus Other Available Models for the Noninvasive Prediction of Pulmonary Hypertension in Patients with Interstitial Lung Disease

PURPOSE

Pulmonary hypertension (PH) is associated with morbidity and mortality in patients with interstitial lung disease (ILD). Several prediction models have been proposed to predict PH in ILD patients. We sought to discern how previously described prediction models perform in predicting PH in patients with ILD.

METHODS

Patients with ILD who completed a baseline right heart catheterization, from Inova Fairfax Hospital, Northwestern Memorial Hospital, and Asan Medical Center in Korea were enrolled. The performance of various prediction models (FORD model, the FORD calculator, the PH-ILD Detection tool, and the mean pulmonary artery pressure prediction model) were assessed using receiver operating characteristic (ROC) curves and area under the receiver operating characteristic curve (AUROC). There were four definitions of pulmonary hypertension against which the models were evaluated.

RESULTS

There were a total of 192 patients with ILD, of whom 32.8% (n = 63/192) met the modified 5th world symposium on PH definition of precapillary PH. Among the models assessed, the FORD calculator had an AUROC (0.733) that was marginally highest. Subgroup analysis revealed that the FORD index had the highest AUROC (0.817) in patients with idiopathic pulmonary fibrosis, while the FORD calculator had the highest AUROC (0.751) in patients with non-IPF ILD.

CONCLUSION

The FORD model can be used to predict group 3 PH in both IPF patients and non-IPF ILD patients. It could serve as a tool for ILD patient selection for right heart catheterization as well as an enrichment tool for clinical trials targeting the pulmonary vasculature.

Pathophysiology of Group 3 Pulmonary Hypertension Associated with Lung Diseases and/or Hypoxia

Pulmonary hypertension associated with lung diseases and/or hypoxia is classified as group 3 in the clinical classification of pulmonary hypertension. The efficacy of existing selective pulmonary vasodilators for group 3 pulmonary hypertension is still unknown, and it is currently associated with a poor prognosis. The mechanisms by which pulmonary hypertension occurs include hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, a decrease in pulmonary vascular beds, endothelial dysfunction, endothelial-to-mesenchymal transition, mitochondrial dysfunction, oxidative stress, hypoxia-inducible factors (HIFs), inflammation, microRNA, and genetic predisposition. Among these, hypoxic pulmonary vasoconstriction and subsequent pulmonary vascular remodeling are characteristic factors involving the pulmonary vasculature and are the focus of this review. Several factors have been reported to mediate vascular remodeling induced by hypoxic pulmonary vasoconstriction, such as HIF-1α and mechanosensors, including TRP channels. New therapies that target novel molecules, such as mechanoreceptors, to inhibit vascular remodeling are awaited.

Revised Precapillary Pulmonary Hypertension Criteria and Their Prognostic Value in IPF Transplant Waitlist Survival

Idiopathic pulmonary fibrosis (IPF) is a leading indication for lung transplantation. Pulmonary hypertension (PH), a common comorbidity in IPF, has gained renewed attention following the updated ESC/ERS guidelines, which redefine diagnostic thresholds for PH. This study evaluates the impact of the revised PH criteria on transplant waitlist outcomes among IPF patients. Specifically, we assessed the prevalence of PH under the new guidelines and its association with waitlist survival. We conducted a retrospective analysis using the OPTN/SRTR database, including 14,156 IPF candidates listed for lung transplantation. Survival analyses were performed using Kaplan-Meier and multivariate models to examine the influence of revised mPAP and PVR thresholds on waitlist mortality. The prevalence of PH, defined by the revised criteria, was significantly higher compared to the prior definition. Kaplan-Meier analysis demonstrated worse waitlist survival for patients with PH under both diagnostic thresholds. However, multivariate analysis revealed that mPAP and PVR thresholds were not independently predictive of mortality. Instead, clinical parameters, including 6MWD, functional status, BMI, FVC, PaCO2, and double lung transplant preference, were significant predictors of waitlist mortality. In conclusion, while the revised PH diagnostic criteria increase PH prevalence in IPF patients, their independent prognostic utility for waitlist survival is limited. This national transplant database study underscores the importance of comprehensive clinical evaluation and timely referral for transplantation in managing IPF with PH.

Dissecting the lung transcriptome of pulmonary fibrosis-associated pulmonary hypertension

Integrative multiomics can help elucidate the pathophysiology of pulmonary fibrosis (PF)-associated pulmonary hypertension (PH) (PF-PH). Weighted gene coexpression network analysis (WGCNA) was performed on a transcriptomic dataset of explanted lung tissue from 116 patients with PF. Patients were stratified by pulmonary vascular resistance (PVR), and differential gene expression analysis was conducted. Gene modules were correlated with hemodynamics at the time of transplantation and tested for enrichment in the lung transcriptomics signature of an independent pulmonary arterial hypertension (PAH) cohort. We found 1,250 differentially expressed genes between high and low PVR groups. WGCNA identified that black and yellowgreen modules negatively correlated with PVR, whereas the tan and darkgrey modules are positively correlated with PVR in PF-PH. In addition, the tan module showed the strongest enrichment for an independent PAH gene signature, suggesting shared gene expression patterns between PAH and PF-PH. Pharmacotranscriptomic analysis using the Connectivity Map implicated the tan and darkgrey modules as potentially pathogenic in PF-PH, given their combined module signature demonstrated a high negative connectivity score for treprostinil, a medication used in the treatment of PF-PH, and a high positive connectivity score for bone morphogenetic protein (BMP) loss of function. Pathway enrichment analysis revealed that inflammatory pathways and oxidative phosphorylation were downregulated, whereas epithelial-mesenchymal transition was upregulated in modules associated with increased PVR. Our integrative systems biology approach to the lung transcriptome of PF with and without PH identified several PH-associated coexpression modules and gene targets with shared molecular features with PAH warranting further investigation to uncover potential new therapies for PF-PH.NEW & NOTEWORTHY An integrative systems biology approach that included transcriptomic analysis of explanted lung tissue from patients with pulmonary fibrosis (PF) with and without pulmonary hypertension (PH) undergoing lung transplantation, combined with hemodynamic correlation and pharmacotranscriptomics, identified modules of genes associated with pulmonary vascular disease severity. Comparison with an independent pulmonary arterial hypertension (PAH) dataset identified shared gene expression patterns between PAH and PF-PH.

Pulmonary Hypertension in Interstitial Lung Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Pulmonary hypertension (PH) is a key complication in interstitial lung disease (ILD), with recent therapeutic advances.

RESEARCH QUESTION

What are the diagnostic evaluation, epidemiologic features, associated factors, prognostic significance, and outcome measures in interventional trials for PH in patients with ILD in the current literature?

STUDY DESIGN AND METHODS

The Ovid MEDLINE, Embase, and CENTRAL databases were searched for original research evaluating PH in participants with ILD of any cause. The definition of PH was based on the investigators' criteria.

RESULTS

Three hundred two studies were included, with varying diagnostic evaluations used to define PH. Commonly used diagnostic tests were right heart catheterization (56%) and transthoracic echocardiography (50%). The pooled prevalence for PH in general populations with ILD was 36% (95% CI, 30%-42%) using right heart catheterization and 34% (95% CI, 29%-38%) using transthoracic echocardiography. Lower diffusion capacity of the lungs for carbon monoxide, worse oxygenation status, reduced exercise capacity, increased pulmonary artery to aorta ratio and pulmonary artery diameter, and elevated serum brain natriuretic peptide consistently were associated with the presence of PH in at least 60% of reported studies. The presence of PH was associated with increased symptom burden and worse prognosis. Outcome measures in interventional trials of PH in ILD focused on changes in pulmonary vascular hemodynamics and 6-min walk distance.

INTERPRETATION

PH is a common complication in ILD with significant health impacts. A standardized definition with prospective evaluation of risk-stratified assessments for PH using identified associated risk factors is warranted. Our findings provide an evidence base for validation as surrogate end points in future PH interventional trials in ILD.

TRIAL REGISTRY

International Prospective Register of Systematic Reviews; No.: CRD42021255394; URL: https://www.crd.york.ac.uk/prospero/.

Pulmonary vascular resistance predicts the mortality in patients with bronchiectasis-associated pulmonary hypertension

OBJECTIVE

Pulmonary hypertension is a severe complication of bronchiectasis, characterized by elevated pulmonary vascular resistance (PVR) and subsequent right heart failure. The association between PVR and mortality in bronchiectasis-associated pulmonary hypertension has not been investigated previously.

METHODS

In the present study, a retrospective analysis was conducted on 139 consecutive patients diagnosed with bronchiectasis-associated pulmonary hypertension based on right heart catheterization, enrolled between January 2010 and June 2023. Baseline clinical characteristics and hemodynamic assessment were analyzed. The survival time for each patient was calculated in months from the date of diagnosis until the date of death or, if the patient was still alive, until their last visit.

RESULTS

Patients with bronchiectasis-associated pulmonary hypertension exhibited estimated survival rates of 89.5, 70, and 52.9 at 1-year, 3-year, and 5-year intervals respectively, with a median survival time of 67 months. Multivariable Cox regression analysis revealed that increased age [(adjusted hazard ratio per year 1.042, 95% confidence interval (CI) 1.008-1.076, P  = 0.015] and elevated PVR (adjusted HR per 1 Wood Units 1.115, 95% CI 1.015-1.224, P  = 0.023) were associated with an increased risk of all-cause mortality. In contrast, higher BMI was associated with a decreased risk of all-cause death (adjusted hazard ratio per 1 kg/m 2 0.915, 95% CI 0.856-0.979, P  = 0.009). Receiver-operating characteristic analyses identified a cutoff value for PVR at 4 Wood Units as predictive for all-cause death within 3 years [area under the curve (AUC) = 0.624; specificity= 87.5%; sensitivity= 35.8%; P  < 0.05]. Patients with a PVR greater than 4 Wood Units had a significantly higher risk of all-cause death compared with those with 4 Wood Units or less (adjusted hazard ratio 2.392; 95% CI 1.316-4.349; P  = 0.019). Notably, there were no significant differences in age, sex, BMI, WHO functional class, 6-min walk distance, and NT-proBNP levels at baseline between patients categorized as having 4 Wood Units or less or greater than 4 Wood Units for PVR.

CONCLUSION

Based on these data, PVR could serve as a discriminative marker for distinguishing between nonsevere pulmonary hypertension (PVR ≤ 4 Wood Units) and severe pulmonary hypertension (PVR > 4 Wood Units). The utilization of a PVR cutoff value of 4.0 Wood Units provides enhanced prognostic capabilities for predicting mortality.

Phenotypes in pulmonary hypertension

The clinical classification of pulmonary hypertension (PH) has guided diagnosis and treatment of patients with PH for several decades. Discoveries relating to underlying mechanisms, pathobiology and responses to treatments for PH have informed the evolution in this clinical classification to describe the heterogeneity in PH phenotypes. In more recent years, advances in imaging, computational science and multi-omic approaches have yielded new insights into potential phenotypes and sub-phenotypes within the existing clinical classification. Identification of novel phenotypes in pulmonary arterial hypertension (PAH) with unique molecular profiles, for example, could lead to new precision therapies. Recent phenotyping studies have also identified groups of patients with PAH that more closely resemble patients with left heart disease (group 2 PH) and lung disease (group 3 PH), which has important prognostic and therapeutic implications. Within group 2 and group 3 PH, novel phenotypes have emerged that reflect a persistent and severe pulmonary vasculopathy that is associated with worse prognosis but still distinct from PAH. In group 4 PH (chronic thromboembolic pulmonary disease) and sarcoidosis (group 5 PH), the current approach to patient phenotyping integrates clinical, haemodynamic and imaging characteristics to guide treatment but applications of multi-omic approaches to sub-phenotyping in these areas are sparse. The next iterations of the PH clinical classification are likely to reflect several emerging PH phenotypes and improve the next generation of prognostication tools and clinical trial design, and improve treatment selection in clinical practice.

A Case of Interstitial Lung Disease-Related Pulmonary Hypertension Successfully Treated with Inhaled Iloprost

Pulmonary hypertension (PH) associated with interstitial lung disease (ILD) (PH-ILD) significantly worsens clinical symptoms and survival, with no effective treatment available. This case report presents the successful treatment of PH-ILD with inhaled iloprost in a patient with idiopathic pulmonary fibrosis (IPF). The patient, a 68-year-old female, was diagnosed with IPF in 2018 and was maintained on pirfenidone. She experienced stable disease until March 2023, when she developed progressive exertional dyspnea, despite stability indicated by a computed tomography (CT) scan, without progression. Transthoracic echocardiography (TTE) and right heart catheterization (RHC) confirmed PH-ILD with a mean pulmonary artery pressure (mPAP) of 43 mmHg. Due to the ineffectiveness of sildenafil and a CT scan indicating stable IPF, a repeat RHC was performed, which showed a worsening of PH (mPAP 62 mmHg). Consequently, inhaled iloprost, at a dosage of 10 mcg every eight hours, was added to the existing antifibrotic agent. After two months, the patient experienced reduced exertional dyspnea and home oxygen requirements. By the seventh month, pulmonary function tests, the six-minute walk test, and RHC parameters (mPAP 37 mmHg) showed marked improvements. This case suggests that inhaled iloprost may be beneficial for managing PH-ILD. Further research is needed to confirm the efficacy of iloprost in PH-ILD treatment.

A comprehensive map of proteoglycan expression and deposition in the pulmonary arterial wall in health and pulmonary hypertension

Changes in the extracellular matrix of pulmonary arteries (PAs) are a key aspect of vascular remodeling in pulmonary hypertension (PH). Yet, our understanding of the alterations affecting the proteoglycan (PG) family remains limited. We sought to investigate the expression and spatial distribution of major vascular PGs in PAs from healthy individuals and various PH groups (chronic obstructive pulmonary disease: PH-COPD, pulmonary fibrosis: PH-PF, idiopathic: IPAH). PG regulation, deposition, and synthesis were notably heightened in IPAH, followed by PH-PF, with minor alterations in PH-COPD. Single-cell analysis unveiled cell-type and disease-specific PG regulation. Agrin expression, a basement membrane PG, was increased in IPAH, with PA endothelial cells (PAECs) identified as a major source. PA smooth muscle cells (PASMCs) mainly produced large-PGs, aggrecan and versican, and small-leucine-like proteoglycan (SLRP) biglycan, whereas the major PGs produced by adventitial fibroblasts were SLRP decorin and lumican. In IPAH and PF-PH, the neointima-forming PASMC population increased the expression of all investigated large-PGs and SLRPs, except fibroblast-predominant decorin (DCN). Expression of lumican, versican, and biglycan also positively correlated with collagen 1α1/1α2 expression in PASMCs in patients with IPAH and PH-PF. We demonstrated that transforming growth factor-beta (TGF-β) regulates versican and biglycan expression, indicating their contribution to vessel fibrosis in IPAH and PF-PH. We furthermore show that certain circulating PG levels display a disease-dependent pattern, with increased decorin and lumican across all patient groups, while versican was elevated in PH-COPD and IPAH and biglycan reduced in IPAH. These findings suggest unique compartment-specific PG regulation in different forms of PH, indicating distinct pathological processes.NEW & NOTEWORTHY Idiopathic pulmonary arterial hypertension (IPAH) pulmonary arteries (PAs) displayed the greatest proteoglycan (PG) changes, with PH associated with pulmonary fibrosis (PH-PF) and PH associated with chronic obstructive pulmonary disease (PH-COPD) following. Agrin, an endothelial cell-specific PG, was solely upregulated in IPAH. Among all cells, neo-intima-forming smooth muscle cells (SMCs) displayed the most significant PG increase. Increased levels of circulating decorin, lumican, and versican, mainly derived from SMCs, and adventitial fibroblasts, may serve as systemic indicators of pulmonary remodeling, reflecting perivascular fibrosis and neointima formation.

Targeting IL-11 to reduce fibrocyte circulation and lung accumulation in animal models of pulmonary hypertension-associated lung fibrosis

BACKGROUND AND PURPOSE

IL-11 is a member of the IL-6 family of cytokine initially considered as haematopoietic and cytoprotective factor. Recent evidence indicates that IL-11 promotes lung fibrosis and pulmonary hypertension in animal models and is elevated in lung tissue of patients with pulmonary fibrosis and pulmonary hypertension. Fibrocytes are bone marrow-derived circulating cells that participate in lung fibrosis and pulmonary hypertension, but the role of IL-11 on fibrocytes is unknown. We investigated the role of IL-11 system on fibrocyte activation in different in vitro and in vivo models of lung fibrosis associated with pulmonary hypertension.

EXPERIMENTAL APPROACH

Human fibrocytes were isolated from peripheral blood of six healthy donors. Recombinant human (rh)-IL-11 and soluble rh-IL-11 receptor, α subunit (IL-11Rα) were used to stimulated fibrocytes in vitro to measure:- cell migration in a chemotactic migration chamber, fibrocyte to endothelial cell adhesion in a microscope-flow chamber and fibrocyte to myofibroblast transition. Mouse lung fibrosis and pulmonary hypertension was induced using either IL-11 (s.c.) or bleomycin (intra-tracheal), while in the rat monocrotaline (intra-tracheal) was used. In vivo siRNA-IL-11 was administered to suppress IL-11 in vivo.

KEY RESULTS

RhIL-11 and soluble rhIL-11Rα promote fibrocyte migration, endothelial cell adhesion and myofibroblast transition. Subcutaneous (s.c.) IL-11 infusion elevates blood, bronchoalveolar and lung tissue fibrocytes. SiRNA-IL-11 transfection in bleomycin and monocrotaline animal models reduces blood and lung tissue fibrocytes and reduces serum CXCL12 and CXCL12/CXCR4 lung expression.

CONCLUSION AND IMPLICATIONS

Targeting IL-11 reduces fibrocyte circulation and lung accumulation in animal models of pulmonary hypertension-associated lung fibrosis.

Oxygen saturation recovery after 6-minute walk test in patients with idiopathic pulmonary fibrosis

BACKGROUND

The six-minute walk test (6MWT) is widely used to assess functional capacity and prognosis in patients with idiopathic pulmonary fibrosis (IPF). However, studies on oxygen saturation recovery after the 6MWT in patients with IPF are rare. In our study, we investigated the relationship between oxygen saturation recovery time and dyspnea, fatigue, quality of life, prognostic markers and pulmonary hypertension (PH).

METHODS

In this cross-sectional study, IPF patients diagnosed according to current guidelines and followed up in our Interstitial Lung Disease Outpatient Clinic between 2021 and 2022 were included. Demographics, data from spirometry, diffusion capacity measurement, arterial blood gas analysis, transthoracic echocardiography and the 6MWT were recorded. The oxygen saturation recovery time, distance saturation product (DSP), gender-age-physiology (GAP) index and composite physiological index (CPI) scores were calculated. Dyspnea severity was assessed by the modified Medical Research Council (mMRC) and Dyspnoea-12 (D-12) scales, fatigue severity by the Multidimensional Fatigue Inventory (MFI-20) and quality of life by the St George's Respiratory Questionnaire (SGRQ).

RESULTS

Fifty IPF patients (34 men, 16 women, age: 66.8 ± 7.3 years) were included in the study. The mean FVC was 77.8 ± 19.3%, the DLCO was 52.9 ± 17.1%, the 6-minute walk distance (6MWD) was 385.7 ± 90.6 m, the GAP index was 3.5 ± 1.5, and the CPI was 43.7 ± 14.1. Oxygen saturation after the 6MWT reached pretest values at an average of 135.6 ± 73.5 s. The oxygen saturation recovery time was longer in patients with higher GAP index scores (Rs = 0.870, p < 0.001), CPI scores (Rs = 0.906, p < 0.001), desaturation (Rs = 0.801, p < 0.001), FVC%/DLCO% (Rs = 0.432, p = 0.002), sPAP (Rs = 0.492, p = 0.001), TRV (Rs = 0.504, p = 0.001), mMRC (Rs = 0.913, p < 0.001), MFI-20 (Rs = 0.944, p < 0.001), D-12 scale (Rs = 0.915, p < 0.001) and SGRQ scores (Rs = 0.927, p < 0.001); lower FVC (%) (Rs=-0.627, p < 0.001), DLCO (%) (Rs=-0.892, p < 0.001), PaO2 (Rs=-0.779, p < 0.001), DSP (Rs=-0.835, p < 0.001), and 6MWD (Rs=-0.763, p < 0.001). A total of twenty patients (40%) exhibited an increased risk of PH. According to our multiple regression analysis, oxygen saturation recovery time was independently associated with the GAP index (p = 0.036), the lowest oxygen saturation occurring during the 6MWT (p = 0.011) and the SGRQ score (p < 0.001).

CONCLUSIONS

Our results showed that oxygen saturation recovery time is associated with dyspnea, fatigue, quality of life, increased risk of PH and prognostic markers in IPF. Therefore, we recommend continuous measurement of oxygen saturation after 6MWT until pretest values are reached.

Delineating excess comorbidities in idiopathic pulmonary fibrosis: an observational study

BACKGROUND

Our study examined whether prevalent and incident comorbidities are increased in idiopathic pulmonary fibrosis (IPF) patients when compared to matched chronic obstructive pulmonary disease (COPD) patients and control subjects without IPF or COPD.

METHODS

IPF and age, gender and smoking matched COPD patients, diagnosed between 01/01/1997 and 01/01/2019 were identified from the Clinical Practice Research Datalink GOLD database multiple registrations cohort at the first date an ICD-10 or read code mentioned IPF/COPD. A control cohort comprised age, gender and pack-year smoking matched subjects without IPF or COPD. Prevalent (prior to IPF/COPD diagnosis) and incident (after IPF/COPD diagnosis) comorbidities were examined. Group differences were estimated using a t-test. Mortality relationships were examined using multivariable Cox proportional hazards adjusted for patient age, gender and smoking status.

RESULTS

Across 3055 IPF patients, 38% had 3 or more prevalent comorbidities versus 32% of COPD patients and 21% of matched control subjects. Survival time reduced as the number of comorbidities in an individual increased (p < 0.0001). In IPF, prevalent heart failure (Hazard ratio [HR] = 1.62, 95% Confidence Interval [CI]: 1.43-1.84, p < 0.001), chronic kidney disease (HR = 1.27, 95%CI: 1.10-1.47, p = 0.001), cerebrovascular disease (HR = 1.18, 95%CI: 1.02-1.35, p = 0.02), abdominal and peripheral vascular disease (HR = 1.29, 95%CI: 1.09-1.50, p = 0.003) independently associated with reduced survival. Key comorbidities showed increased incidence in IPF (versus COPD) 7-10 years prior to IPF diagnosis.

INTERPRETATION

The mortality impact of excessive prevalent comorbidities in IPF versus COPD and smoking matched controls suggests that multiorgan mechanisms of injury need elucidation in patients that develop IPF.

Predictors of Mortality in Pulmonary Hypertension-Associated Chronic Lung Disease

Background/Objectives: Pulmonary hypertension (PH) often accompanies chronic lung diseases. Several chronic lung diseases with PH portends unfavorable outcomes. We investigated which variables in this cohort of patients with chronic lung disease and PH predicts mortality. Methods: This is a retrospective analysis of patients with chronic lung disease and PH at a single tertiary, academic center. The underlying lung disease included were COPD, IPF, other fibrotic ILD, non-fibrotic ILD, fibrotic sarcoidosis, and CPFE. All patients had right heart catheterization diagnostic of PH as well as pulmonary function testing data including 6 min walk testing. Univariable and multivariate Cox regression was performed to identify variables associated with mortality. Results: We identified 793 patients with chronic lung disease and PH. In total, 144 patients died prior to potential lung transplant. In multivariable Cox regression IPF, other fibrotic ILD, non-fibrotic ILD, and CPFE were significantly associated with an increased risk of mortality. Severe PH (PVR > 5 WU), FEV1 < 30% predicted, FVC < 40% predicted, 6 min walk distance < 150 m were also significantly associated with an increased risk of mortality. Conclusions: Carrying a diagnosis of IPF, CPFE, fibrotic ILD, or non-fibrotic ILD with PH has an increased risk of mortality as compared to COPD with PH. Hemodynamic, PVR > 5 WU, 6 min walk test less than 150 m, as well as spirometric data including FEV1 < 30% and FVC < 40% predicted were independently associated with an increased risk of death.

Pharmacological treatment in Idiopathic Pulmonary Fibrosis: current issues and future perspectives

Idiopathic pulmonary fibrosis (IPF) represents a fibrotic interstitial lung disease characterized by uncertain etiology and poor prognosis. Over the years, the path to effective treatments has been marked by a series of advances and setbacks. The introduction of approved antifibrotic drugs, pirfenidone and nintedanib, marked a pivotal moment in the management of IPF. However, despite these advances, these drugs are not curative, although they can slow the natural progression of the disease. The history of drug therapy for IPF goes together with the increased understanding of the pathogenic mechanisms underlying the disease. Based on that, current research efforts continue to explore new therapies, possible personalized treatment strategies, drug combinations, and potential biomarkers for diagnosis and prognosis. In this review, we outline the route that led to the discover of the first effective therapies, ongoing clinical trials, and future directions in the search for more effective treatments.

Pirfenidone and nintedanib attenuates pulmonary artery endothelial and smooth muscle cells transformations induced by IL-11

Idiopathic pulmonary fibrosis (IPF) associated to pulmonary hypertension (PH) portends a poor prognosis, characterized by lung parenchyma fibrosis and pulmonary artery remodeling. Serum and parenchyma levels of Interleukin 11 (IL-11) are elevated in IPF-PH patients and contributes to pulmonary artery remodeling and PH. However, the effect of current approved therapies against IPF in pulmonary artery remodeling induced by IL-11 is unknown. The aim of this study is to analyze the effects of nintedanib and pirfenidone on pulmonary artery endothelial and smooth muscle cell remodeling induced by IL-11 in vitro. Our results show that nintedanib (NTD) and pirfenidone (PFD) ameliorates endothelial to mesenchymal transition (EnMT), pulmonary artery smooth muscle cell to myofibroblast-like transformation and pulmonary remodeling in precision lung cut slices. This study provided also evidence of the inhibitory effect of PFD and NTD on IL-11-induced endothelial and muscle cells proliferation and senescence. The inhibitory effect of these drugs on monocyte arrest and angiogenesis was also studied. Finally, we observed that IL-11 induced canonical signal transducer and activator of transcription 3 (STAT3) and non-canonical mitogen-activated protein kinase 1/2 (ERK1/2) phosphorylation, but, PFD and NTD only inhibited ERK1/2 phosphorylation. Therefore, this study provided evidence of the inhibitory effect of NTD and PFD on markers of pulmonary artery remodeling induced by IL-11.

Bioinformatics analysis of hypoxia associated genes and inflammatory cytokine profiling in COPD-PH

Pulmonary hypertension (PH) in chronic obstructive pulmonary disease (COPD) is associated with worse clinical outcomes and decreased survival rates. In absence of disease specific diagnostic/therapeutic targets and unclear pathophysiology, there is an urgent need for the identification of potential genetic/molecular markers and disease associated pathways. The present study aims to use a bioinformatics approach to identify and validate hypoxia-associated gene signatures in COPD-PH patients. Additionally, hypoxia-related inflammatory profile is also explored in these patients. Microarray dataset obtained from the Gene Expression Omnibus repository was used to identify differentially expressed genes (DEGs) in a hypoxic PH mice model. The top three hub genes identified were further validated in COPD-PH patients, with chemokine (C-X-C motif) ligand 9 (CXCL9) and CXCL12 showing significant changes in comparison to healthy controls. Furthermore, multiplexed analysis of 10 inflammatory cytokines, tumor necrosis factor alpha (TNF-α), transforming growth factor β (TGF-β), interleukin 1-beta (IL-1β), IL-4, IL-5, IL-6, IL-13, IL-17, IL-18 and IL-21 was also performed. These markers showed significant changes in COPD-PH patients as compared to controls. They also exhibited the ability to differentially diagnose COPD-PH patients in comparison to COPD. Additionally, IL-6 and IL-17 showed significant positive correlation with systolic pulmonary artery pressure (sPAP). This study is the first report to assess the levels of CXCL9 and CXCL12 in COPD-PH patients and also explores their link with the inflammatory profile of these patients. Our findings could be extended to better understand the underlying disease mechanism and possibly used for tailoring therapies exclusive for the disease.

Antifibrotic therapy in progressive pulmonary fibrosis: a review of recent advances

INTRODUCTION

Progressive pulmonary fibrosis (PPF) is a manifestation of a heterogenous group of underlying interstitial lung disease (ILD) diagnoses, defined as non-idiopathic pulmonary fibrosis (IPF) progressive fibrotic ILD meeting at least two of the following criteria in the previous 12 months: worsening respiratory symptoms, absolute decline in forced vital capacity (FVC) more than or equal to 5% and/or absolute decline in diffusing capacity for carbon monoxide (DLCO) more than or equal to 10% and/or radiological progression.

AREAS COVERED

The authors subjectively reviewed a synthesis of literature from PubMed to identify recent advances in the diagnosis and characterisation of PPF, treatment recommendations, and management challenges. This review provides a comprehensive summary of recent advances and highlights future directions for the diagnosis, management, and treatment of PPF.

EXPERT OPINION

Recent advances in defining the criteria for PPF diagnosis and licensing of treatment are likely to support further characterisation of the PPF patient population and improve our understanding of prevalence. The diagnosis of PPF remains challenging with the need for a specialised ILD multidisciplinary team (MDT) approach. The evidence base supports the use of immunomodulatory therapy to treat inflammatory ILDs and antifibrotic therapy where PPF develops. Treatment needs to be tailored to the specific underlying disease and determined on a case-by-case basis.

Relationship between idiopathic interstitial pneumonias (IIPs) and connective tissue disease-related interstitial lung disease (CTD-ILD): A narrative review

While idiopathic interstitial pneumonia (IIP) centering on idiopathic pulmonary fibrosis (IPF) is the most prevalent interstitial lung disease (ILD), especially in the older adult population, connective tissue disease (CTD)-related ILD is the second most prevalent ILD. The pathogenesis of IPF is primarily fibrosis, whereas that of other ILDs, particularly CTD-ILD, is mainly inflammation. Therefore, a precise diagnosis is crucial for selecting appropriate treatments, such as antifibrotic or immunosuppressive agents. In addition, some patients with IIP have CTD-related features, such as arthritis and skin eruption, but do not meet the criteria for any CTD, this is referred to as interstitial pneumonia with autoimmune features (IPAF). IPAF is closely associated with idiopathic nonspecific interstitial pneumonia (iNSIP) and cryptogenic organizing pneumonia (COP). Furthermore, patients with iNSIP or those with NSIP with OP overlap frequently develop polymyositis/dermatomyositis after the diagnosis of IIP. Acute exacerbation of ILD, the most common cause of death, occurs more frequently in patients with IPF than in those with other ILDs. Although acute exacerbation of CTD-ILD occurs at a low rate of incidence, patients with rheumatoid arthritis, microscopic polyangiitis, or systemic sclerosis experience more acute exacerbation of CTD-ILD than those with other CTD. In this review, the features of each IIP, focusing on CTD-related signatures, are summarized, and the pathogenesis and appropriate treatments to improve the prognoses of patients with various ILDs are discussed.

Derivation and validation of a noninvasive prediction tool to identify pulmonary hypertension in patients with IPF: Evolution of the model FORD

BACKGROUND

The administration of inhaled prostanoids to patients with pulmonary hypertension (PH) related to idiopathic pulmonary fibrosis (IPF) and other fibrotic lung diseases improves functional outcomes. Selection of patients with IPF at risk for concomitant PH to undergo right heart catheterization (RHC) remains challenging. We sought to develop a clinical prediction tool based on common noninvasive parameters to identify PH in patients with IPF.

METHODS

A prediction model based on noninvasive parameters was derived from patients enrolled in the ARTEMIS-IPF randomized, placebo-controlled clinical trial. Predictor variables were tested for association with the presence of PH diagnosed based on RHC. The derived multivariable logistic regression model and associated point-score index were then externally validated in a real-world cohort of patients with IPF.

RESULTS

Of the 481 patients included in the ARTEMIS-IPF study, 9.8% (N = 47) were diagnosed with PH related to IPF. Four variables were associated with PH and were included in the final model: forced vital capacity/diffusing capacity for carbon monoxide ratio (F), oxygen saturation nadir during 6-minute walk test (6MWT) (O), race (R), and distance ambulated during 6MWT (D). A model containing continuous predictors (FORD calculator) and a simple point-score system (FORD index) performed similarly well in the derivation cohort (area under the curve [AUC]: 0.75 and 0.75, respectively) and validation cohort (AUC: 0.69 and 0.69, respectively).

CONCLUSIONS

The FORD models are simple, validated tools incorporating noninvasive parameters that can be applied to identify patients at risk of PH related to IPF who may benefit from invasive testing.

Impact of the New Definition of Pulmonary Hypertension on the Prevalence of Primary Graft Dysfunction in Lung Transplant Recipients

BACKGROUND & AIM

Pulmonary hypertension (PH) secondary to lung disease (Group-3 PH) is the second leading cause of PH. The role of PH as a risk factor for primary graft dysfunction (PGD) following lung transplant (LT) is controversial.

OBJECTIVE

To assess the impact that the new definition of PH had on the prevalence of PH in patients with advanced lung disease-candidate for LT, and its association with the occurrence of PGD.

METHOD

A retrospective study was performed in all patients undergoing cardiac catheterisation referred for consideration as candidates to LT in a centre between 1 January 2017 and 31 December 2022. The baseline and haemodynamic characteristics of patients were analysed, along with the occurrence of PGD and post-transplant course in those who ultimately underwent transplantation.

RESULTS

A total of 396 patients were included. Based on the new 2022 European Society of Cardiology/European Respiratory Society definitions, as many as 70.7% of patients met PH criteria. Since the introduction of the 2022 definition, a significant reduction was observed in the frequency of severe Group-3 PH (41.1% vs 10.3%; p<0.001), with respect to the 2015 definition. As many as 236 patients underwent transplantation. None of the variables associated with PH was identified as a risk factor for PGD.

CONCLUSION

The new classification did not have any impact on the prevalence of PGD after transplantation. These results exclude that any significant differences exist in the baseline characteristics or post-transplant course of patients with Group-3 PH vs unclassified PH.

Efficacy of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension patients with pulmonary comorbidity

Background

Balloon pulmonary angioplasty (BPA) is an established treatment for inoperable chronic thromboembolic pulmonary hypertension (CTEPH), but its efficacy in CTEPH patients with a pulmonary comorbidity has not been well-studied. Here, we compared post-BPA outcomes between CTEPH patients with and without chronic pulmonary disease at baseline and analyzed predictors of BPA success.

Methods

From August 2017 to October 2022, 62 patients with inoperable CTEPH who underwent BPA were consecutively enrolled and grouped based on the presence of a pulmonary comorbidity at baseline. All patients underwent transthoracic echocardiography, pulmonary function tests, and right heart catheterization. Pre- and post-BPA data were evaluated to identify factors that influence the success of BPA.

Results

Among the 62 CTEPH patients, BPA was considered successful in 50 patients and unsuccessful in 12 patients. Responders to BPA had better exercise capacity and right heart function at baseline, but no differences in hemodynamic or respiratory function were detected between the groups. In CTEPH patients with chronic pulmonary disease (n = 14), BPA significantly improved mean pulmonary arterial pressure, pulmonary vascular resistance and right heart function parameters. Only CTEPH patients without chronic pulmonary disease (n = 48) exhibited significant improvement in 6-minute walk distance and respiratory function. Multivariate logistic regression analysis showed that pulmonary comorbidity at baseline was independently associated with the efficacy of BPA.

Conclusions

BPA provided significantly improvements in hemodynamics and right heart function in CTEPH patients, independent of pulmonary comorbidity at baseline. However, pulmonary comorbidity can negatively impact post-BPA outcomes.

Phenotyping exercise limitation of patients with Interstitial Fibrosing Lung Disease: the importance of exercise hemodynamics

INTRODUCTION AND OBJECTIVE

Left-heart dysfunction and pulmonary vasculopathy are increasingly recognized as contributing factors of exercise capacity limitation in interstitial fibrosing lung disease (IFLD). Moreover, the clinical significance of exercise pulmonary hypertension (ePH) in pulmonary and cardiac diseases has been documented, representing a risk factor for decreased exercise capacity and survival, progression to resting pulmonary hypertension (PH) and overall clinical worsening. We conducted a prospective study aiming at: (a) assessing the prevalence of PH and ePH in a cohort of 40 functionally limited patients with IFLD, (b) determining the post-capillary (postC) or pre-capillary (preC) etiology of either PH or ePH in this cohort, and (c) examining the correlations between invasively and non-invasively measured exercise variables among hemodynamic groups.

PATIENTS AND METHODS

40 IFLD patients underwent cardiopulmonary evaluation, including: clinical examination, lung function tests, 6-minute walking test, heart ultrasonography, cardiopulmonary exercise test and, finally, right heart catheterization (RHC). Resting hemodynamic evaluation was followed by the exercise protocol proposed by Herve et al, using a bedside cycle ergometer in the supine position. Abnormal elevation of mean pulmonary artery pressure (mPAP) above 30mmHg during exercise, with respect to abnormal elevation of cardiac output (CO) below 10 L/min (mPAP-CO ratio ⩾3 mmHg·min·L-1) was used to define ePH (Herve et al, 2015). Secondary hemodynamic evaluation involved detection of abnormal pulmonary arterial wedge pressure (PAWP) increase at peak exercise in relation to CO. Specifically, ΔPAWP/ΔCO >2 mmHg/L per minute determined an abnormal PAWP elevation (Bentley et al, 2020).

RESULTS

Among the 40-patient cohort, 25% presented postC PH, 37.5% preC PH, 27.5% ePH, with the remaining 10% recording normal hemodynamics. PAWP evaluation during exercise revealed a postC etiology in 4 out of the 11 patients presenting ePH, and a postC etiology in 6 out of the 15 patients presenting resting preC PH. Mean values of non-invasive variables did not display statistically significant differences among hemodynamic groups, except for: diffusing capacity for carbon monoxide (DLCO), carbon monoxide transfer coefficient (KCO) and the ratio of functional vital capacity to DLCO (FVC%/DLCO%), which were lower in both ePH and PH groups (p < 0.05). Resting values of CO, cardiac index (CI), stroke volume (SV) and pulmonary vascular compliance (PVC) were significantly impaired in ePH, preC-PH and postC-PH groups when compared to the normal group.

CONCLUSIONS

Both PH and ePH were highly prevalent within the IFLD patient group, suggesting that RHC should be offered more frequently in functionally limited patients. Diffusion capacity markers must thus guide decision making, in parallel to clinical evaluation. ePH was associated to lower resting CO and PVC, in a similar way to resting PH, indicating the relevance of cardiopulmonary function to exercise limitation. Finally, the use of the ΔPAWP/ΔCO>2 criterion further uncovered PH of postcapillary etiology, highlighting the complexity of hemodynamics in IFLD.

CLINICALTRIALS

gov ID: NCT03706820.

The Role of Proton Pump Inhibitors in the Realm of Idiopathic Pulmonary Fibrosis and its Associated Comorbidities: A Systematic Review

As the global incidence of idiopathic pulmonary fibrosis (IPF) is on the rise, there is a need for better diagnostic criteria, better treatment options, early and appropriate diagnosis, adequate care, and a multidisciplinary approach to the management of patients. This systematic review explores the role of proton pump inhibitors (PPIs) in IPF and answers the question, "Does proton pump inhibitor improve only the prognosis of gastroesophageal associated idiopathic pulmonary fibrosis or for other types of idiopathic pulmonary fibrosis too?" We used PubMed (PMC) and Google Scholar for data collection for this systematic review and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for conducting this review. After in-depth literature screening and quality appraisal, 12 articles were selected for this systematic review. On the one hand, the efficacy of PPI therapy is supported by research such as the CAPACITY and ASCEND trials, a pilot randomized control trial (RCT) investigating the role of omeprazole in IPF and a bidirectional two-sample Mendelian randomization (MR) study, respectively. On the other hand, a systematic review and meta-analysis on antacid and antireflux surgery in IPF negate these results and show no statistical significance. Questions regarding the efficacy of PPI therapy must be dealt with in an adequately powered multicenter and double-blinded randomized control trial. The anti-inflammatory properties of antacids can serve as the cornerstone for future trials. In the following systematic review, antacid, antireflux therapy, omeprazole, and proton pump therapy are synonymous with stomach acid suppression therapy.

Treatment of idiopathic pulmonary fibrosis and progressive pulmonary fibrosis: A position statement from the Thoracic Society of Australia and New Zealand 2023 revision

Idiopathic pulmonary fibrosis (IPF) is a progressive disease leading to significant morbidity and mortality. In 2017 the Thoracic Society of Australia and New Zealand (TSANZ) and Lung Foundation Australia (LFA) published a position statement on the treatment of IPF. Since that time, subsidized anti-fibrotic therapy in the form of pirfenidone and nintedanib is now available in both Australia and New Zealand. More recently, evidence has been published in support of nintedanib for non-IPF progressive pulmonary fibrosis (PPF). Additionally, there have been numerous publications relating to the non-pharmacologic management of IPF and PPF. This 2023 update to the position statement for treatment of IPF summarizes developments since 2017 and reaffirms the importance of a multi-faceted approach to the management of IPF and progressive pulmonary fibrosis.

Evolution of pulmonary hypertension in interstitial lung disease: a journey through past, present, and future

Interstitial lung diseases (ILD) are a spectrum of disorders often complicated by pulmonary hypertension (PH) in its course. The pathophysiologic mechanism of WHO group 3 PH is different to other forms of PH. The advent of PH is a harbinger for adverse events like mortality and morbidity, implying that the PH component of disease expedites deteriorated clinical outcomes. In fact, WHO group 3 PH due to ILD has the worse prognosis among all groups of PH. Hence, early detection of PH by a comprehensive screening method is paramount. Given considerable overlap in clinical manifestations between ILD and PH, early detection of PH is often elusive. Despite, the treatment of PH due to ILD has been frustrating until recently. Clinical trials utilizing PAH-specific pulmonary vasodilators have been ongoing for years without desired results. Eventually, the INCREASE study (2018) demonstrated beneficial effect of inhaled Treprostinil to treat PH in ILD. In view of this pioneering development, a paradigm shift in clinical approach to this disease phenotype is happening. There is a renewed vigor to develop a well validated screening tool for early detection and management. Currently inhaled Treprostinil is the only FDA approved therapy to treat this phenotype, but emergence of a therapy has opened a plethora of research toward new drug developments. Regardless of all these recent developments, the overall outlook still remains grim in this condition. This review article dwells on the current state of knowledge of pre-capillary PH due to ILD, especially its diagnosis and management, the recent progresses, and future evolutions in this field.

Pulmonary vascular pressure respiratory swings in COPD and ILD candidates for lung transplantation: Large but different

We analyzed the effect of respiratory swings on interpreting intravascular pulmonary vascular pressures (PVPs) in chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) candidates for lung transplantation (LTx) and the role of the alterations in pulmonary function tests on the dynamic respiratory variations. Twenty-eight consecutive patients were included. All patients underwent a complete hemodynamic study (right atrial, mean pulmonary arterial, and pulmonary arterial occlusion pressures [RAP, mPAP, and PAOP]-) and pulmonary function testing (force vital capacity [FVC], forced expiratory volume in the first second [FEV1], and residual volume [RV]). A subgroup of 10 patients underwent simultaneous esophageal pressure (PES). All hemodynamic parameters and PES were collected during apnea after an unforced expiration (ee) and during spontaneous breathing averaging five respiratory cycles (mrc). The respiratory swing (osc) was estimated as the difference between maximum-minimum values of pressures during the respiratory cycle. Intravascular RAPee, mPAPee, and PAOPee were higher than mrc values (p < 0.05), leading to 11% of pulmonary hypertension (PH) misdiagnosis and 37% of postcapillary PH misclassification. PAOPosc of COPD was higher than ILD patients and RAPosc (p < 0.05). Only PAOPosc correlated with FVC, FEV1, and RV (p < 0.05). ILD PESmrc was lower than COPD (p < 0.05), and it was associated with a significantly higher transmural than intravascular RAPmrc, mPAPmrc, and PAOPmrc. PESmrc was significantly correlated with FVC. Transmural mPAPmrc and PAOPmrc readings determined around 20% of reclassification of the patients compared to ee measurements. Candidates for LTx showed large respiratory swings in PVP, which were correlated with pulmonary function alterations. mrc PVP would be more closely approximated to the true transmural PVP leading to PH reclassification. Adjusting PVP for PES should be considered in COPD and ILD candidates of LTx with severe alterations in pulmonary functional tests and suspicion of a PESmrc far from 0. PES respiratory swings could be different in ILD to COPD patients.

Examining prevalence and predictors of pulmonary hypertension in adults with idiopathic pulmonary fibrosis: a population-based analysis in the United States

Pulmonary hypertension (PH) often complicates idiopathic pulmonary fibrosis (IPF), a progressive parenchymal lung disease. We investigated predictors of PH in IPF hospitalizations in the United States. We identified IPF hospital- izations with or without PH using the National Inpatient Sample (2018) and relevant ICD-10-CM codes. We com- pared demographics, comorbidities, PH prevalence, and its multivariable predictors adjusted for confounders among patients with IPF. In 2018, 30,335 patients from 30,259,863 hospitalizations had IPF, of which 8,075 (26.6%) had PH. Black (41%), Hispanic (21.3%), and female (28.7%) patients had higher rates of PH compared to white patients (25%). The IPF-PH cohort was hospitalized more often in urban teaching (77.7% vs. 72.2%), Midwest, and West hospitals vs. non-PH cohort. Comorbidities including congestive heart failure (2.08 [1.81-2.39]), valvular disease (2.12 [1.74-2.58]), rheumatoid arthritis/collagen vascular disease (1.32 [1.08-1.61]) predicted higher odds of PH. The PH-IPF cohort was less often routinely discharged (35.4%) and more likely to be transferred to intermediate care facilities (22.6%) and home health care (27.1%) (P < 0.001). The PH-IPF group had higher rates of all-cause mortality (12.3% vs. 9.4%), cardiogenic shock (2.4% vs. 1%), dysrhythmia (37.6% vs. 29%), and cardiac arrest (2.7% vs. 1.5%) vs. non-PH cohort (all P < 0.001). Patients with PH-IPF also had longer hospital stays (9 vs. 8) and a higher median cost ($23,054 vs. $19,627, P < 0.001). Nearly 25% of IPF hospitalizations with PH were linked to higher mortality, extended stays, and costs, emphasizing the need to integrate demographic and comorbidity predictors into risk stratification for improved outcomes in patients with IPF-PH.

Severe pulmonary hypertension-interstitial lung disease presenting as right ventricular failure: stabilisation with intravenous prostacyclin and maintenance with inhaled prostacyclin

Background

Pulmonary hypertension (PH) leads to increased morbidity and mortality in interstitial lung disease (ILD). While the INCREASE trial highlighted the use of inhaled prostacyclin in PH-ILD patients, such therapy may be inadequate when right ventricular failure (RVF) is also present. In this study, we report the use of intravenous prostacyclin in three PH-ILD patients to stabilise right ventricular (RV) function, with a subsequent transition to maintenance therapy with inhaled prostacyclin.

Methods

We evaluated three consecutive PH-ILD patients with RVF. RV afterload and pulmonary vascular resistance (PVR) were treated with intravenous prostacyclin during the induction phase of the therapy. Patients transitioned from intravenous prostacyclin to the maintenance phase of the treatment with inhaled prostacyclin once three transition criteria were met: cardiac index (CI) >2 L·min-1·m-2, PVR <7 Wood units (WU) and tricuspid annular plane systolic excursion (TAPSE) change >1 mm or TAPSE >1.6 cm.

Results

Pre-treatment parameters for the three patients were a mean PVR of 14.3 WU, a mean Fick CI of 1.8 L·min-1·m-2 and a mean TAPSE of 1.4 cm. The average intravenous prostacyclin dose at the time of transition to maintenance therapy was 20.7 ng·kg-1·m-2 of treprostinil. At 3-months follow-up, the mean PVR was 6.3 WU, Fick CI 2.2 L·min-1·m-2 and TAPSE 1.7 cm.

Conclusion

This case series of three PH-ILD patients with RVF introduces the concept of an initial intravenous prostacyclin induction phase, followed by a transition to maintenance therapy with inhaled prostacyclin. Further development of this treatment algorithm with a refinement of the transition criteria, potential testing in a clinical trial and a longer-term follow-up period is warranted to improve the outcomes of advanced PH-ILD patients with concomitant RVF.

Management of Pulmonary Hypertension Associated with Chronic Lung Disease

Pulmonary hypertension (PH) is a common complication of chronic lung diseases, particularly in chronic obstructive pulmonary disease (COPD) and interstitial lung diseases (ILD) and especially in advanced disease. It is associated with greater mortality and worse clinical course. Given the high prevalence of some respiratory disorders and because lung parenchymal abnormalities might be present in other PH groups, the appropriate diagnosis of PH associated with respiratory disease represents a clinical challenge. Patients with chronic lung disease presenting symptoms that exceed those expected by the pulmonary disease should be further evaluated by echocardiography. Confirmatory right heart catheterization is indicated in candidates to surgical treatments, suspected severe PH potentially amenable with targeted therapy, and, in general, in those conditions where the result of the hemodynamic assessment will determine treatment options. The treatment of choice for these patients who are hypoxemic is long-term oxygen therapy and pulmonary rehabilitation to improve symptoms. Lung transplant is the only curative therapy and can be considered in appropriate cases. Conventional vasodilators or drugs approved for pulmonary arterial hypertension (PAH) are not recommended in patients with mild-to-moderate PH because they may impair gas exchange and their lack of efficacy shown in randomized controlled trials. Patients with severe PH (as defined by pulmonary vascular resistance >5 Wood units) should be referred to a center with expertise in PH and lung diseases and ideally included in randomized controlled trials. Targeted PAH therapy might be considered in this subset of patients, with careful monitoring of gas exchange. In patients with ILD, inhaled treprostinil has been shown to improve functional ability and to delay clinical worsening.

[Pulmonary hypertension associated with lung disease]

Lung diseases and hypoventilation syndromes are often associated with pulmonary hypertension (PH). In most cases, PH is not severe. This is defined hemodynamically by a mean pulmonary arterial pressure (PAPm) > 20 mmHg, a pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg and a pulmonary vascular resistance of ≤ 5 Wood units (WU). Both the non-severe (PVR ≤ 5 WU) and much more the severe PH (PVR > 5 WU) have an unfavorable prognosis.If PH is suspected, it is recommended to primarily check whether risk factors for pulmonary arterial hypertension (PAH, group 1 PH) or chronic thromboembolic pulmonary hypertension (CTEPH, group 4 PH) are present. If risk factors are present or there is a suspicion of severe PH in lung patients, it is recommended that the patient should be presented to a PH outpatient clinic promptly.For patients with severe PH associated with lung diseases, personalized, individual therapy is recommended - if possible within the framework of therapy studies. Currently, a therapy attempt with PH specific drugs should only be considered in COPD patients if the associated PH is severe and a "pulmonary vascular" phenotype (severe precapillary PH, but typically only mild to moderate airway obstruction, no or mild hypercapnia and DLCO < 45 % of predicted value) is present. In patients with severe PH associated with interstitial lung disease phosphodiesterase-5-inhibitors may be considered in individual cases. Inhaled treprostinil may be considered also in non-severe PH in this patient population.

Relationship of Main Pulmonary Artery (Truncus Pulmonalis) Diameter With Hospital Stay and Mortality in Pulmonary Hypertension Patients Admitted to the Emergency Department

INTRODUCTION

Pulmonary hypertension (PH) is a haemodynamic and pathophysiological disease significantly associated with morbidity and mortality. The increase in pulmonary vascular resistance, high pulmonary artery pressure and wall tension that occurs in PH results in dilatation of the main pulmonary artery (truncus pulmonalis), one of the largest and most important vessels in the body. The aim of this study is to investigate the relationship between the diameter of the truncus pulmonalis and hospitalization, length of hospital stay, and mortality in patients diagnosed with PH.

METHODS

Demographic characteristics, number of Emergency Department (ED) admissions, post-admission status, treatment, truncus pulmonalis diameter, and mortality were evaluated statistically through the patient files of 115 PH patients who presented to the ED of Fırat University Faculty of Medicine, Elazığ, Türkiye, between January 2022 and December 2022.

RESULTS

Of the 115 PH patients who came to the ED, 70 (60.8%) were women and 45 (39.2%) were men, with a mean age of 78.77±8.72 years. Fifty-one of these patients were discharged from the ED after treatment, and 64 were hospitalized. The mean length of hospital stay was two (min=0, max=38) days. Thoracic CT scans demonstrated that the mean diameter of the truncus pulmonalis of the patients was 34.874±3.288 mm (35.20±3.6509 mm in women, 34.367±2.5836 mm in men; p₌0.351) and there was no statistically significant relationship with mortality (p=0.496), hospitalization (p=0.806), and length of hospital stay (p=0.416). There was a statistically significant relationship between mortality rate and male gender (p=0.02) and comorbidity (p=0.001).

CONCLUSION

It was determined that there was no statistically significant relationship between the truncus pulmonalis diameter and gender, comorbidity, hospitalization, length of hospital stay, and mortality in this study in which single-centre one-year admissions of PH, which differ in aetiology, epidemiology, and demographic features were examined. However, among the patient demographics, a significant relationship was determined between gender and the number of comorbidities and mortality.

Pulmonary Hypertension in Interstitial Lung Disease: Updates in Disease, Diagnosis, and Therapeutics

Pulmonary hypertension is a debilitating condition that frequently develops in the setting of interstitial lung disease, likely related to chronic alveolar hypoxemia and pulmonary vascular remodeling. This disease process is likely to be identified more frequently by providers given recent advancements in definitions and diagnostic modalities, and provides practitioners with emerging opportunities to improve patient outcomes and quality of life. Despite years of data suggesting against the efficacy of pulmonary vasodilator therapy in patients with pulmonary hypertension due to interstitial lung disease, new data have emerged identifying promising advancements in therapeutics. The authors present to you a comprehensive review of pulmonary hypertension in interstitial lung disease, reviewing our current understanding of pathophysiology, updates in diagnostic approaches, and highlights of recent clinical trials which provide an effective approach for medical management.

Comorbidity of Pulmonary Fibrosis and COPD/Emphysema: Research Status, Trends, and Future Directions --------- A Bibliometric Analysis from 2004 to 2023

Objective

The comorbidity of pulmonary fibrosis and COPD/emphysema has garnered increasing attention. However, no bibliometric analysis of this comorbidity has been conducted thus far. This study aims to perform a bibliometric analysis to explore the current status and cutting-edge trends in the field, and to establish new directions for future research.

Methods

Statistical computing, graphics, and data visualization tools such as VOSviewer, CiteSpace, Biblimatrix, and WPS Office were employed.

Results

We identified a total of 1827 original articles and reviews on the comorbidity of pulmonary fibrosis and COPD/emphysema published between 2004 and 2023. There was an observed increasing trend in publications related to this comorbidity. The United States, Japan, and the United Kingdom were the countries with the highest contributions. Professor Athol Wells and the University of Groningen had the highest h-index and the most articles, respectively. Through cluster analysis of co-cited documents, we identified the top 17 major clusters. Keyword analysis predicted that NF-κB, oxidative stress, physical activity, and air pollution might be hot spots in this field in the future.

Conclusion

This bibliometric analysis demonstrates a continuous increasing trend in literature related to the comorbidity of pulmonary fibrosis and COPD/emphysema. The research hotspots and trends identified in this study provide a reference for in-depth research in this field, aiming to promote the development of the comorbidity of pulmonary fibrosis and COPD/emphysema.

Identification of the shared gene signatures between pulmonary fibrosis and pulmonary hypertension using bioinformatics analysis

Pulmonary fibrosis (PF) and pulmonary hypertension (PH) have common pathophysiological features, such as the significant remodeling of pulmonary parenchyma and vascular wall. There is no effective specific drug in clinical treatment for these two diseases, resulting in a worse prognosis and higher mortality. This study aimed to screen the common key genes and immune characteristics of PF and PH by means of bioinformatics to find new common therapeutic targets. Expression profiles are downloaded from the Gene Expression Database. Weighted gene co-expression network analysis is used to identify the co-expression modules related to PF and PH. We used the ClueGO software to enrich and analyze the common genes in PF and PH and obtained the protein-protein interaction (PPI) network. Then, the differential genes were screened out in another cohort of PF and PH, and the shared genes were crossed. Finally, RT-PCR verification and immune infiltration analysis were performed on the intersection genes. In the result, the positive correlation module with the highest correlation between PF and PH was determined, and it was found that lymphocyte activation is a common feature of the pathophysiology of PF and PH. Eight common characteristic genes (ACTR2, COL5A2, COL6A3, CYSLTR1, IGF1, RSPO3, SCARNA17 and SEL1L) were gained. Immune infiltration showed that compared with the control group, resting CD4 memory T cells were upregulated in PF and PH. Combining the results of crossing characteristic genes in ImmPort database and RT-PCR, the important gene IGF1 was obtained. Knocking down IGF1 could significantly reduce the proliferation and apoptosis resistance in pulmonary microvascular endothelial cells, pulmonary smooth muscle cells, and fibroblasts induced by hypoxia, platelet-derived growth factor-BB (PDGF-BB), and transforming growth factor-β1 (TGF-β1), respectively. Our work identified the common biomarkers of PF and PH and provided a new candidate gene for the potential therapeutic targets of PF and PH in the future.

Efficacy and Safety of Pirfenidone in Advanced Versus Non-Advanced Idiopathic Pulmonary Fibrosis: Post-Hoc Analysis of Six Clinical Studies

INTRODUCTION

In the European Union (EU), the indication for the antifibrotic pirfenidone prior to April 2023 did not include patients with advanced idiopathic pulmonary fibrosis (IPF). This analysis compared the efficacy and safety of pirfenidone in advanced IPF versus non-advanced IPF.

METHODS

Data were included from the following studies of pirfenidone: ASCEND (NCT01366209); CAPACITY (004 [NCT00287716] and 006 [NCT00287729]); RECAP (NCT00662038; advanced IPF defined as percent predicted forced vital capacity [%FVC] < 50% and/or percent predicted carbon monoxide diffusing capacity [%DLco] < 35% at baseline); PASSPORT (NCT02699879; advanced IPF defined as baseline %FVC < 50%); and SP-IPF (NCT02951429; patients with advanced IPF [defined as %DLco ≤ 40% at screening] at risk of group 3 pulmonary hypertension).

RESULTS

In the pooled ASCEND/CAPACITY studies, the annual mean rate of FVC decline from baseline to Week 52 was significantly lower for pirfenidone versus placebo in advanced (p = 0.0035) and non-advanced IPF (p = 0.0001). Rate of all-cause mortality over 52 weeks was numerically lower for pirfenidone versus placebo in advanced and non-advanced IPF. In RECAP, the mean annual rate of FVC decline from baseline to Week 180 of pirfenidone treatment was similar in patients with advanced (- 141.5 mL) and non-advanced IPF (- 153.5 mL). In SP-IPF, the mean annual rate of FVC decline and rate of all-cause mortality from baseline to Week 52 in patients treated with placebo + pirfenidone were - 93.0 mL and 20.2%, respectively. No new safety signals were identified, and the safety profile of pirfenidone in patients with advanced IPF was generally consistent with that of non-advanced IPF.

CONCLUSIONS

These results highlight the benefit of pirfenidone treatment in patients with advanced and non-advanced IPF. As such, the indication for pirfenidone in the EU has now been updated to include the treatment of adult patients with advanced IPF.

TRIAL REGISTRATIONS

ASCEND (NCT01366209), CAPACITY 004 (NCT00287716), CAPACITY 006 (NCT00287729), RECAP (NCT00662038), PASSPORT (NCT02699879), and SP-IPF (NCT02951429).

Pulmonary hypertension associated with lung disease: new insights into pathomechanisms, diagnosis, and management

Patients with chronic lung diseases, particularly interstitial lung disease and chronic obstructive pulmonary disease, frequently develop pulmonary hypertension, which results in clinical deterioration, worsening of oxygen uptake, and an increased mortality risk. Pulmonary hypertension can develop and progress independently from the underlying lung disease. The pulmonary vasculopathy is distinct from that of other forms of pulmonary hypertension, with vascular ablation due to loss of small pulmonary vessels being a key feature. Long-term tobacco exposure might contribute to this type of pulmonary vascular remodelling. The distinct pathomechanisms together with the underlying lung disease might explain why treatment options for this condition remain scarce. Most drugs approved for pulmonary arterial hypertension have shown no or sometimes harmful effects in pulmonary hypertension associated with lung disease. An exception is inhaled treprostinil, which improves exercise capacity in patients with interstitial lung disease and pulmonary hypertension. There is a pressing need for safe, effective treatment options and for reliable, non-invasive diagnostic tools to detect and characterise pulmonary hypertension in patients with chronic lung disease.

Cohort study to evaluate prognostic factors in idiopathic pulmonary fibrosis patients introduced to oxygen therapy

While high-level evidence is lacking, numerous retrospective studies have depicted the value of supplemental oxygen in idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases, and its use should be encouraged where necessary. The clinical course and survival of patients with IPF who have been introduced to oxygen therapy is still not fully understood. The objective of this study was to clarify overall survival, factors associated with prognosis, and causes of death in IPF patients after the start of oxygen therapy. This is a prospective cohort multicenter study, enrolling patients with IPF who started oxygen therapy at 19 hospitals with expertise in interstitial lung disease. Baseline clinical data at the start of oxygen therapy and 3-year follow-up data including death and cause of death were assessed. Factors associated with prognosis were analyzed using univariable and multivariable analyses. One hundred forty-seven eligible patients, of whom 86 (59%) were prescribed ambulatory oxygen therapy and 61 (41%) were prescribed long-term oxygen therapy, were recruited. Of them, 111 died (76%) during a median follow-up of 479 days. The median survival from the start of oxygen therapy was 537 ± 74 days. In the univariable analysis, low body mass index (BMI), low forced vital capacity (FVC), low diffusion capacity (DLCO), resting hypoxemia, short 6 min-walk distance, and high COPD assessment test (CAT) score were significantly associated with poor prognosis. Multivariable analysis revealed low BMI, low FVC, low DLCO, low minimum SpO2 on 6MWT, and high CAT score were independent factors for poor prognosis. The overall survival of IPF patients after starting oxygen therapy is about 1.5 years. In addition to pulmonary function tests, 6MWT and patient reported outcomes can be used to predict prognosis more accurately.Clinical Trial Registration: UMIN000009322.

ACE2 overexpression in corticotropin-releasing-hormone cells offers protection against pulmonary hypertension

Background

Pulmonary hypertension (PH), characterized by elevated pulmonary pressure and right heart failure, is a systemic disease involving inappropriate sympathetic activation and an impaired gut-brain-lung axis. Global overexpression of angiotensin converting enzyme 2 (ACE2), a cardiopulmonary protective enzyme of the renin-angiotensin system, attenuates PH induced by chronic hypoxia. Neurons within the paraventricular nucleus of the hypothalamus (PVN) that synthesize corticotropin-releasing hormone (CRH) are activated by stressors, like hypoxia, and this activation augments sympathetic outflow to cardiovascular tissues. These data coupled with our observations that ACE2 overexpression in CRH cells (CRH-ACE2KI mice) decreases anxiety-like behavior via suppression of hypothalamic-pituitary-adrenal (HPA) axis activity by decreasing CRH synthesis, led us to hypothesize that selective ACE2 overexpression in CRH neurons would protect against hypoxia-induced PH.

Methods

CRH-ACE2KI and WT male and female mice were exposed to chronic hypoxia (10%O2) or normoxia (21%O2) for 4 weeks in a ventilated chamber with continuous monitoring of oxygen and carbon dioxide concentrations (n = 7-10/group). Pulmonary hemodynamics were measured with Millar pressure catheters then tissues were collected for histological analyses.

Results

Chronic hypoxia induced a significant increase (36.4%) in right ventricular (RV) systolic pressure (RVSP) in WT mice, which was not observed in CRH-ACE2KI mice. No significant differences in RVSP were observed between male and female mice in any of the groups.

Conclusion

Overexpression of ACE2 in CRH cells was protective against hypoxia-induced PH. Since the majority of expression of CRH is in brain nuclei such as paraventricular nucleus of the hypothalamus (PVN) and/or central nucleus of the amygdala (CeA) these data indicate that the protective effects of ACE2 are, at least in part, centrally mediated. This contributes to the systemic nature of PH disease and that CRH neurons may play an important role in PH.

Clinical assessment for pulmonary hypertension in interstitial lung disease

BACKGROUND

Pulmonary hypertension (PH) is an important complication of interstitial lung disease (ILD), as its development confers a poor prognosis. There are no specific recommendations for methods of assessment for PH in ILD populations.

AIMS

To determine current assessment practices for PH in an Australian ILD centre.

METHODS

In the Austin Health ILD database, 162 consecutive patients with idiopathic pulmonary fibrosis or connective tissue disease-associated ILD were identified and retrospectively evaluated for methods of PH assessment with transthoracic echocardiography (TTE), serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and right heart catheterisation (RHC) in relation to patient demographic and physiological parameters.

RESULTS

The median follow-up was 30 (14.4-56.4) months. At baseline, vital capacity was 80.0 ± 18.4% predicted, and diffusing capacity for carbon monoxide was 59.6 ± 15.2% predicted. Evaluation for PH was performed in 147 (90.7%) patients, among whom 105 (64.8%) had TTE performed at least once. At the initial TTE, 33.7% patients had high probability of PH, defined as RVSP >40 mmHg + RAp and/or right ventricular dysfunction. At the time of the most recent TTE, these criteria were met in 45 (52.3%) patients. Elevated serum NT-proBNP levels during the first year were observed in 47 (38.8%) patients. Only 14 (8.6%) patients had RHC.

CONCLUSION

Our institutional PH assessment practice in ILD demonstrates a substantial prevalence of probable PH at baseline. As new therapies emerge for the treatment of PH in ILD, well-defined screening practices are important in this population for early identification and optimal management.