Predictors of Mortality in Patients with Interstitial Lung Disease-Associated Pulmonary Hypertension

Pulmonary hypertension associated with lung diseases

Pulmonary hypertension (PH) associated with chronic lung disease (CLD) is both common and underrecognised. The presence of PH in the setting of lung disease has been consistently shown to be associated with worse outcomes. Recent epidemiological studies have advanced understanding of the heterogeneity of this patient population and shown that defining both the specific type of CLD as well as the severity of PH (i.e. deeper phenotyping) is necessary to inform natural history and prognosis. A systematic diagnostic approach to screening and confirmation of suspected PH in CLD is recommended. Numerous uncontrolled studies and one phase 3 randomised, controlled trial have suggested a benefit in treating PH in some patients with CLD, specifically those with fibrotic interstitial lung disease (ILD). However, other studies in diseases such as COPD-PH showed adverse outcomes with some therapies. Given the expanding list of approved pharmacological treatments for pulmonary arterial hypertension, developing a treatment algorithm for specific phenotypes of CLD-PH is required. This article will summarise existing data in COPD, ILD and other chronic lung diseases, and provide recommendations for classification of CLD-PH and approach to the diagnosis and management of these challenging patients.

Noninvasive diagnostic modalities and prediction models for detecting pulmonary hypertension associated with interstitial lung disease: a narrative review

Pulmonary hypertension (PH) is highly prevalent in patients with interstitial lung disease (ILD) and is associated with increased morbidity and mortality. Widely available noninvasive screening tools are warranted to identify patients at risk for PH, especially severe PH, that could be managed at expert centres. This review summarises current evidence on noninvasive diagnostic modalities and prediction models for the timely detection of PH in patients with ILD. It critically evaluates these approaches and discusses future perspectives in the field. A comprehensive literature search was carried out in PubMed and Scopus, identifying 39 articles that fulfilled inclusion criteria. There is currently no single noninvasive test capable of accurately detecting and diagnosing PH in ILD patients. Estimated right ventricular pressure (RVSP) on Doppler echocardiography remains the single most predictive factor of PH, with other indirect echocardiographic markers increasing its diagnostic accuracy. However, RVSP can be difficult to estimate in patients due to suboptimal views from extensive lung disease. The majority of existing composite scores, including variables obtained from chest computed tomography, pulmonary function tests and cardiopulmonary exercise tests, were derived from retrospective studies, whilst lacking validation in external cohorts. Only two available scores, one based on a stepwise echocardiographic approach and the other on functional parameters, predicted the presence of PH with sufficient accuracy and used a validation cohort. Although several methodological limitations prohibit their generalisability, their use may help physicians to detect PH earlier. Further research on the potential of artificial intelligence may guide a more tailored approach, for timely PH diagnosis.

A composite score based on cardiovascular parameters can predict the mortality risk of patients with newly diagnosed interstitial lung disease: A prospective observational study

BACKGROUND

It is crucial to identify factors that can predict the risk of mortality in patients newly diagnosed with interstitial lung disease (ILD). This study sought to develop and assess a composite scoring system for mortality prediction among ILD patients based on cardiovascular parameters, which were previously reported as predictors of survival.

METHODS

We prospectively enrolled patients with newly diagnosed ILD and monitored their survival status for 24 months. Surviving and deceased patients were compared regarding their baseline characteristics including clinical, pulmonary, and cardiovascular parameters. A system of composite scores was established based on significant cardiovascular parameters and the Gender-Age-Physiology (GAP) score. Receiver operating characteristic curves were generated to identify their optimal cut-off values. Univariate as well as multiple multivariate regression models were built to investigate the mortality prediction of different individual and combined parameters.

RESULTS

Ninety-six patients newly diagnosed with ILD underwent cardiovascular evaluation. In univariate analysis, three cardiovascular parameters were identified as significant predictors of mortality risk in ILD patients, either individually or as a combination of composite scores: tricuspid regurgitation velocity > 3.1 m/s; N-terminal pro-B-type natriuretic peptide level > 300 pg/ml and computed tomography pulmonary artery/ascending aorta diameter ratio > 0.9. In multivariate analysis, a composite score of those parameters [hazard ratio (HR) = 2.37 (confidence interval [CI]:1.06-5.33); p = 0.037; Score 1] and GAP score [HR = 1.62 (CI: 1.11-2.36); p = 0.012] were the most significant predictors for mortality among ILD patients. Combination of Score 1 and GAP score (Score 2) can increase the accuracy of survival predictions (area under the curve 0.83; p < 0.001).

CONCLUSIONS

A composite score based on cardiovascular parameters and the GAP score can be used to predict the risk of mortality of patients with ILD. Such a score achieved better diagnostic accuracy than the GAP score alone. Nevertheless, further larger-scale randomized controlled trials are required for evaluation of the newly proposed score and confirmation of our results.

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.

Pulmonary vascular dysfunction without pulmonary hypertension: A distinct phenotype in idiopathic pulmonary fibrosis

Pulmonary vascular dysfunction in the absence of pulmonary hypertension (PH) has been observed in patients with idiopathic pulmonary fibrosis (IPF). We describe the prevalence and etiology of elevated pulmonary vascular resistance (PVR) without PH among patients with IPF. Hemodynamic, echocardiographic, and functional respiratory imaging (FRI) data was compared between patients with IPF without PH with normal (<3 wood units) and elevated PVR (≥3 wood units). Mortality between these two groups were compared to patients with IPF and PH. Of 205 patients with IPF, there were 146 patients without PH, of whom 114 (78.1%) had a normal PVR and 32 (21.9%) who had a high PVR. Functional testing and hemodynamics were similar in the two groups, except for the cardiac index which was significantly lower in patients with a high PVR (2.3 vs. 2.6 L/min/m2; p = 0.004). Echocardiographic comparison demonstrated a higher tricuspid regurgitant velocity in those with a high PVR (3.4 vs 3.0 m/s; p = 0.046). FRI revealed proportionately fewer large vessels as a proportion of the vasculature in the patients without PH and elevated PVRs. Among patients without PH, PVR was associated with increased mortality. In conclusion, patients with IPF without PH but a high PVR appear to be a distinct phenotype with a prognosis between those with and without PH, likely reflecting the continuum of vascular dysfunction. The basis for this unique hemodynamic profile could not be definitively discerned although FRI suggested an aberrant anatomical vascular response.

Unmasking a Silent Threat: Improving Pulmonary Hypertension Screening Methods for Interstitial Lung Disease Patients

This article provides a comprehensive overview of the latest literature on the diagnostics and treatment of pulmonary hypertension (PH) associated with interstitial lung disease (ILD). Heightened suspicion for PH arises when the advancement of dyspnoea in ILD patients diverges from the expected pattern of decline in pulmonary function parameters. The complexity of PH associated with ILD (PH-ILD) diagnostics is emphasized by the limitations of transthoracic echocardiography in the ILD population, necessitating the exploration of alternative diagnostic approaches. Cardiac magnetic resonance imaging (MRI) emerges as a promising tool, offering insights into hemodynamic parameters and providing valuable prognostic information. The potential of biomarkers, alongside pulmonary function and cardiopulmonary exercise tests, is explored for enhanced diagnostic and prognostic precision. While specific treatments for PH-ILD remain limited, recent studies on inhaled treprostinil provide new hope for improved patient outcomes.

Predicting New-onset Exertional and Resting Hypoxemia in Fibrotic Interstitial Lung Disease

Rationale: Hypoxemia in fibrotic interstitial lung disease (ILD) indicates disease progression and is of prognostic significance. The onset of hypoxemia signifies disease progression and predicts mortality in fibrotic ILD. Accurately predicting new-onset exertional and resting hypoxemia prompts appropriate patient discussion and timely consideration of home oxygen. Objectives: We derived and externally validated a risk prediction tool for both new-onset exertional and new-onset resting hypoxemia. Methods: This study used ILD registries from Canada for the derivation cohort and from Australia and the United States for the validation cohort. New-onset exertional and resting hypoxemia were defined as nadir oxyhemoglobin saturation < 88% during 6-minute-walk tests, resting oxyhemoglobin saturation < 88%, or the initiation of ambulatory or continuous oxygen. Candidate predictors included patient demographics, ILD subtypes, and pulmonary function. Time-varying Cox regression was used to identify the top-performing prediction model according to Akaike information criterion and clinical usability. Model performance was assessed using Harrell's C-index and goodness-of-fit (GoF) likelihood ratio test. A categorized risk prediction tool was developed. Results: The best-performing prediction model for both new-onset exertional and new-onset resting hypoxemia included age, body mass index, a diagnosis of idiopathic pulmonary fibrosis, and percent predicted forced vital capacity and diffusing capacity of carbon monoxide. The risk prediction tool exhibited good performance for exertional hypoxemia (C-index, 0.70; GoF, P = 0.85) and resting hypoxemia (C-index, 0.77; GoF, P = 0.27) in the derivation cohort, with similar performance in the validation cohort except calibration for resting hypoxemia (GoF, P = 0.001). Conclusions: This clinically applicable risk prediction tool predicted new-onset exertional and resting hypoxemia at 6 months in the derivation cohort and a diverse validation cohort. Suboptimal GoF in the validation cohort likely reflected overestimation of hypoxemia risk and indicated that the model is not flawed because of underestimation of hypoxemia.

Pulmonary Hypertension in the Course of Interstitial Lung Diseases-A Personalised Approach Is Needed to Identify a Dominant Cause and Provide an Effective Therapy

The prevalence of pulmonary hypertension (PH) complicating interstitial lung diseases (ILDs) is 3.5-15% at an early stage, and up to 90% in ILD patients listed for lung transplantation. In addition, other types of PH may occur in patients with ILDs due to concomitant conditions. Therefore, any significant PH occurring in the setting of ILD requires a proper differential workup. PH increases morbidity and mortality in ILDs. The pathomechanisms underlying PH due to ILD (PH-ILD) are not fully known, and there is no straightforward correlation between the presence or severity of PH-ILD and the severity of ILD. Severe PH in mild ILD without other explanatory causes constitutes a dilemma of differentiating between PH due to ILD and pulmonary arterial hypertension coexisting with ILDs. The heterogeneity and poor prognosis of patients with ILDs coexisting with PH necessitate an individualised approach to the management of this condition. This review presents recent advances in understanding and treatment options in PH-ILD. It also addresses practical issues, such as when to suspect and how to screen for PH in ILD, what are the indications for right heart catheterisation, and how to approach an individual ILD patient to determine the dominant PH cause and apply adequate management.

The association between pulmonary artery enlargement and mortality in an Emergency Department population undergoing computed tomography pulmonary angiography

Findings of an enlarged pulmonary artery diameter (PAd) and increased pulmonary artery to ascending aorta ratio (PA:AA) on contrast-enhanced computed tomography pulmonary angiography (CTPA) are associated with increased mortality in particular groups of patients with cardiopulmonary disease. However, the frequency and prognostic significance of these incidental findings has not been studied in unselected patients evaluated in the Emergency Department (ED). This study aims to determine the prevalence and associated prognosis of enlarged pulmonary artery measurements in an ED cohort. We measured PA and AA diameters on 990 CTPA studies performed in the ED. An enlarged PA diameter was defined as >27 mm in females and >29 mm in males, while an increased PA:AA was defined as >0.9. Poisson regression was performed to calculate prevalence ratios for relevant comorbidities, and multivariable Cox regression was performed to calculate hazard ratios (HR) for mortality of patients with enlarged pulmonary artery measurements. An enlarged PAd was observed in 27.9% of 990 patients and was more commonly observed in older patients and in patients with obesity or heart failure. Conversely, PA:AA was increased in 34.2% of subjects, and was more common in younger patients and those with peripheral vascular disease or obesity. After controlling for age, sex, and comorbidities, both enlarged PAd (HR 1.29, 95% CI 1.00-1.68, p = 0.05) and PA:AA (HR 1.70, 95% CI 1.31-2.22 p < 0.01) were independently associated with mortality. In sum, enlarged PAd and increased PA:AA are common in patients undergoing CTPAs in the ED setting and both are independently associated with mortality.

Pathogenesis, clinical features, and phenotypes of pulmonary hypertension associated with interstitial lung disease: A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative - Group 3 Pulmonary Hypertension

Pulmonary hypertension (PH) is a frequent complication of interstitial lung disease (ILD). Although PH has mostly been described in idiopathic pulmonary fibrosis, it can manifest in association with many other forms of ILD. Associated pathogenetic mechanisms are complex and incompletely understood but there is evidence of disruption of molecular and genetic pathways, with panvascular histopathologic changes, multiple pathophysiologic sequelae, and profound clinical ramifications. While there are some recognized clinical phenotypes such as combined pulmonary fibrosis and emphysema and some possible phenotypes such as connective tissue disease associated with ILD and PH, the identification of further phenotypes of PH in ILD has thus far proven elusive. This statement reviews the current evidence on the pathogenesis, recognized patterns, and useful diagnostic tools to detect phenotypes of PH in ILD. Distinct phenotypes warrant recognition if they are characterized through either a distinct presentation, clinical course, or treatment response. Furthermore, we propose a set of recommendations for future studies that might enable the recognition of new phenotypes.

Phosphodiesterase 5 inhibitor treatment and survival in interstitial lung disease pulmonary hypertension: A Bayesian retrospective observational cohort study

BACKGROUND AND OBJECTIVE

Pulmonary hypertension is a life-limiting complication of interstitial lung disease (ILD-PH). We investigated whether treatment with phosphodiesterase 5 inhibitors (PDE5i) in patients with ILD-PH was associated with improved survival.

METHODS

Consecutive incident patients with ILD-PH and right heart catheterisation, echocardiography and spirometry data were followed from diagnosis to death, transplantation or censoring with all follow-up and survival data modelled by Bayesian methods.

RESULTS

The diagnoses in 128 patients were idiopathic pulmonary fibrosis (n = 74, 58%), hypersensitivity pneumonitis (n = 17, 13%), non-specific interstitial pneumonia (n = 12, 9%), undifferentiated ILD (n = 8, 6%) and other lung diseases (n = 17, 13%). Final outcomes were death (n = 106, 83%), transplantation (n = 9, 7%) and censoring (n = 13, 10%). Patients treated with PDE5i (n = 50, 39%) had higher mean pulmonary artery pressure (median 38 mm Hg [interquartile range, IQR: 34, 43] vs. 35 mm Hg [IQR: 31, 38], p = 0.07) and percentage predicted forced vital capacity (FVC; median 57% [IQR: 51, 73] vs. 52% [IQR: 45, 66], p=0.08) though differences did not reach significance. Patients treated with PDE5i survived longer than untreated patients (median 2.18 years [95% CI: 1.43, 3.04] vs. 0.94 years [0.69, 1.51], p = 0.003) independent of all other prognostic markers by Bayesian joint-modelling (HR 0.39, 95% CI: 0.23, 0.59, p < 0.001) and propensity-matched analyses (HR 0.38, 95% CI: 0.22, 0.58, p < 0.001). Survival difference with treatment was significantly larger if right ventricular function was normal, rather than abnormal, at presentation (+2.55 years, 95% CI: -0.03, +3.97 vs. +0.98 years, 95% CI: +0.47, +2.00, p = 0.04).

CONCLUSION

PDE5i treatment in ILD-PH should be investigated by a prospective randomized trial.

Clinical significance of pulmonary hypertension in interstitial lung disease: A consensus statement from the Pulmonary Vascular Research Institute's innovative drug development initiative-Group 3 pulmonary hypertension

Pulmonary hypertension (PH) has been linked to worse outcomes in chronic lung diseases. The presence of PH in the setting of underlying Interstitial Lung Disease (ILD) is strongly associated with decreased exercise and functional capacity, an increased risk of hospitalizations and death. Examining the scope of this issue and its impact on patients is the first step in trying to define a roadmap to facilitate and encourage future research in this area. The aim of our working group is to strengthen the communities understanding of PH due to lung diseases and to improve the care and quality of life of affected patients. This introductory statement provides a broad overview and lays the foundation for further in-depth papers on specific topics pertaining to PH-ILD.

Cardiovascular complications in patients with interstitial lung disease and their correlation with 6-minute walk test and spirometry: A single-center study

Introduction

Pulmonary hypertension and other cardiac complications occur frequently due to chronic hypoxia induced by interstitial lung diseases (ILD) or due to connective tissue disorder itself. Two-dimensional (2D) echocardiography is ideal for identifying abnormalities at a given time. In this study, we tried to detect cardiovascular complications in patients with ILD using 2D echocardiography and correlate them with a 6-minute walk test (6 MWT) and spirometry.

Materials and Methods

This study was carried out for 18 months including 100 consecutive cases of ILD. The diagnosis was made using the latest criteria as per the disease and high-resolution computed tomography (HRCT) thorax. All patients were evaluated with 2D echocardiography, 6 MWT, and spirometry along with routine investigations. Their results were analyzed using STATA 15.1 software.

Result

Cardiovascular involvement was detected in 68% of cases. Pulmonary hypertension predominated with a prevalence of 50%. In spirometry, mean Forced expiratory volume in first second (FEV₁)and Forced vital capacity (FVC) were found to be 54.96 (L) and 53.49 (L), respectively, with a predominant restrictive pattern (89%). There was a significant correlation between baseline saturation of oxygen (SpO₂) and pulmonary arterial systolic pressure (PASP) with a P value of <0.05. Baseline SpO₂ and distance covered in 6 MWT had a significant correlation (P = 0.014).

Conclusion

A baseline or nighttime hypoxia is responsible for developing PAH. Pulmonary arterial hypertension should be suspected in patients unable to perform 6 MWT or having low baseline SpO₂. A routine follow-up with a 6 MWT and baseline SpO₂ should be performed in each visit to identify early deterioration of the disease.

Dominating Cause of Pulmonary Hypertension May Change Over Time-Diagnostic and Therapeutic Considerations in a Patient with Pulmonary Hypertension Due to Rheumatoid Arthritis with Lung Involvement

Chronic lung diseases are one of the most frequent causes of pulmonary hypertension (PH). The diagnostic challenge is to differentiate PH due to chronic lung disease from pulmonary arterial hypertension (PAH) with coexisting chronic lung disease. Moreover, the dominating cause of PH may change over time, requiring the implementation of new diagnostic procedures and new treatment modalities. We present a 68-year-old female, initially diagnosed with PH in the course of interstitial lung disease, with restrictive impairment of lung function. Therapy with immunosuppressive drugs resulted in significant clinical, radiological and functional improvement. However, five years later, arthritis symptoms developed, with PH worsening, despite stable lung disease. The patient was diagnosed with PAH in the course of rheumatoid arthritis. The introduction of sildenafil resulted in marked clinical and hemodynamic responses. Long-term survival (eleven years from PH onset and five years from PAH confirmation) has been achieved, and the patient remains in good functional condition. As the differential diagnosis of PH in patients with lung diseases is complex, the cooperation of pulmonologists and cardiologists is mandatory to obtain therapeutic success.

Cone Beam CT Guidance Improves Transbronchial Lung Cryobiopsy Safety

INTRODUCTION

Determining the cause of diffuse parenchymal lung disease (DPLD) is challenging. While surgical lung biopsy has been the standard approach, transbronchial lung cryobiopsy (TBLC) represents a minimally invasive alternative with an acceptable safety profile and reasonable accuracy. In this study, we prospectively assessed whether the use of cone beam CT (CBCT) coupled with a novel bronchoscope holder and prophylactic administration of vasoconstricting medications decreases potential complications and improves diagnostic accuracy when performing TBLC.

METHODS

33 patients presenting for evaluation of newly diagnosed DPLD were enrolled. Demographic data, pulmonary function values, chest imaging pattern, procedural information, and diagnosis were recorded.

RESULTS

Mean patient age was 67, with the majority Caucasian (n = 26, 79%) and male (n = 20, 61%). Mean pulmonary function values revealed restrictive lung disease (76 ± 14% predicted) and diffusing capacity impairment (52 ± 16%). A non-usual interstitial pneumonia imaging pattern was commonly seen (n = 20, 61%). CBCT guided TBLC was performed in one lobe (n = 29, 88%) or two lobes (n = 4, 12%) with mean probe-to-pleura distance of 4.2 ± 1.3 mm. No peri or post procedural complications occurred. 32 patients (97%) received a histological diagnosis with a final multidisciplinary conference diagnosis possible for 32 (97%).

CONCLUSION

CBCT guided TBLC coupled with a novel articulating scope holder and prophylactic phenylephrine administration has the potential to increase safety and diagnostic yield for patients with newly identified DPLD. Future studies comparing different aspects of this approach in isolation and with other modalities have the potential to refine this procedure to improve patient care.

Acute exacerbation in interstitial lung disease

BACKGROUND:

Information regarding acute exacerbation (AE) in patients with interstitial lung disease (ILD) is limited.

OBJECTIVES:

The objective of the study was to elucidate the clinical features and outcome of AE among ILD patients.

METHODS:

We retrospectively analyzed the data of 667 consecutive ILD (nonidiopathic pulmonary fibrosis [IPF] ILD, n = 463; IPF, n = 204) patients. ILD patients meeting the 2016 definition of AE-IPF were identified. Information analyzed included pulmonary function tests, 6-min walk tests, and right heart catheterization data, among others. Cox regression models were used to identify independent predictors of survival.

RESULTS:

AE was identified in non-IPF ILD (n = 113) and IPF (n = 74). Compared with AE-IPF patients, non-IPF ILD patients with AE were of younger age, predominantly women, and primarily nonsmokers (all, P < 0.0001). The estimated survival probabilities at 1, 3, and 5 years were 88%, 75%, and 70%, respectively, in the ILD without AE group; 80%, 57%, and 50%, respectively, in the non-IPF ILD with AE group; and 53%, 38%, and 28%, respectively, in the AE-IPF group (P < 0.0001 by log-rank analysis). Age, body mass index, IPF diagnosis, AE, diffusion capacity of the lung for carbon monoxide <35% predicted, 6-min walk distance <300 meters, and cardiac index were independent predictors of survival in the ILD cohort.

CONCLUSIONS:

Non-IPF ILD patients with AE have distinct clinical features compared to AE-IPF patients. Importantly, AE is one of many independent risk factors associated with worsened outcomes regardless of the underlying ILD type.