Can a New Scoring System Improve Prediction of Pulmonary Hypertension in Newly Recognised Interstitial Lung Diseases?

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.

Phenotypes of Sarcoidosis-Associated Pulmonary Hypertension-A Challenging Mystery

Sarcoidosis has been a well-recognised risk factor for pulmonary hypertension (PH) for a long time, but still, the knowledge about this concatenation is incomplete. Sarcoidosis-associated PH (SAPH) is an uncommon but serious complication associated with increased morbidity and mortality among sarcoidosis patients. The real epidemiology of SAPH remains unknown, and its pathomechanisms are not fully explained. Sarcoidosis is a heterogeneous and dynamic condition, and SAPH pathogenesis is believed to be multifactorial. The main roles in SAPH development play: parenchymal lung disease with the destruction of pulmonary vessels, the extrinsic compression of pulmonary vessels by conglomerate masses, lymphadenopathy or fibrosing mediastinitis, pulmonary vasculopathy, LV dysfunction, and portal hypertension. Recently, it has been recommended to individually tailor SAPH management according to the predominant pathomechanism, i.e., SAPH phenotype. Unfortunately, SAPH phenotyping is not a straightforward process. First, there are gaps in our understanding of undergoing processes. Second, the assessment of such a pivotal element as pulmonary vasculature on a microscopic level is non-feasible in SAPH patients antemortem. Finally, SAPH is a dynamic condition, multiple phenotypes usually coexist, and patients can switch between phenotypes during the course of sarcoidosis. In this article, we summarise the basic knowledge of SAPH, describe SAPH phenotypes, and highlight some practical problems related to SAPH phenotyping.

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.

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 PH-ILD Detection tool: External validation and use in patients with ILD

Pulmonary hypertension (PH) results in increased morbidity and mortality in patients with interstitial lung disease (ILD). Early recognition of PH in this population is essential for planning diagnostic testing, initiating therapy, and evaluating for lung transplantation. The previously developed PH-ILD Detection tool has significant potential in the evaluation and treatment of ILD patients; the aim of this study was to validate the tool in an independent, multicenter cohort of patients. We conducted a retrospective review of prospectively collected data from 161 ILD patients. Patients were stratified into low- (n = 78, 48.4%), intermediate- (n = 54, 33.5%), and high-risk (n = 29, 18.0%) groups based on the score obtained with the tool. Intermediate- and high-risk patients underwent follow-up echocardiogram (TTE); 49.4% (n = 41) had an abnormal TTE suggestive of underlying PH. These patients underwent right heart catheterization; PH-ILD was diagnosed in 73.2% (n = 30) of these cases. The PH-ILD Detection tool has a sensitivity of 93.3%, specificity of 90.9%, and area-under-the-curve of 0.921 for diagnosing PH in ILD patients, validating the findings from the original study and establishing the tool as a fundamental resource for early recognition of PH in ILD patients.

Predictors of Pulmonary Hypertension and Right Ventricular Dysfunction in Patients with Hypersensitivity Pneumonitis

BACKGROUND

Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) that occurs in susceptible individuals in response to various inhaled antigens. The fibrotic phenotype of HP is characterized by disease progression and can lead to pulmonary hypertension (PH). The aim of this study was to estimate the prevalence of PH and to identify predictors of PH in patients with chronic HP.

METHODS

We conducted an observational longitudinal study that included 85 patients with an established diagnosis of HP. Clinical examination, quality of life questionnaires, high-resolution computed tomography (HRCT) of the chest, arterial blood gases analyses, six-minute walking test (6-MWT), pulmonary function tests, and echocardiography were performed.

RESULTS

Patients were divided into groups with fibrotic (71.8%) and nonfibrotic phenotype (28.2%). PH was detected in 41 (48.2%) patients. Patients with PH had the predominant fibrotic phenotype of HP, were older, more symptomatic, and had a higher FVC/DLco ratio. The most significant predictors of PH were CT signs of fibrosis, finger clubbing, FVC/DLco, decreased distance, and SpO2 at the end of 6-MWT, as well as the presence of cardiovascular diseases.

CONCLUSIONS

PH is a common condition in patients with chronic HP, especially with the fibrotic phenotype. Early detection of the PH predictors is necessary for the timely diagnosis of this complication of HP.

New 6-Minute-Walking Test Parameter—Distance/Desaturation Index (DDI) Correctly Diagnoses Short-Term Response to Immunomodulatory Therapy in Hypersensitivity Pneumonitis

The six-minute-walking test (6MWT) is an easy-to-perform, cheap and valuable tool to assess the physical performance of patients. It has been used as one of the endpoints in many clinical trials investigating treatment efficacy in pulmonary arterial hypertension and idiopathic pulmonary fibrosis. However, the utility of 6MWT in patients diagnosed with hypersensitivity pneumonitis (HP) is still under investigation. The aim of the present retrospective study was to assess the value of different 6MWT parameters, including the newly developed distance-desaturation index (DDI), to evaluate immunomodulatory treatment outcomes in HP patients. Methods: 6MWT parameters (distance, initial saturation, final saturation, desaturation, distance-saturation product (DSP), and DDI) were analyzed at baseline and after 3 to 6 months of treatment with corticosteroids alone or in combination with azathioprine. Results: 91 consecutive HP patients diagnosed and treated in a single pulmonary unit from 2005 to 2017 entered the study. There were 44 (48%) males and 52 (57%) patients with fibrotic HP (fHP). Sixty-three patients (69%) responded to treatment (responders) and 28 (31%) did not respond (non-responders). In the responders group, all parameters assessed during 6MWT significantly improved, whereas in non-responders, they worsened. Medians (95% CI) of best indices were post-treatment DDI/baseline DDI—1.67 (1.85–3.63) in responders versus 0.88 (0.7–1.73) in non-responders (p = 0.0001) and change in walking distance–51 m (36–72 m) in responders, versus 10.5 m (−61.2–27.9) in non-responders (p = 0.0056). The area under the curve (AUC) of receiver operating characteristics (ROC) for post-treatment DDI/baseline DDI was 0.74 and the optimal cut-off was 1.075, with 71% of specificity and 71% of sensitivity. Conclusions: 6MWT may be used as a tool to assess and monitor the response to immunomodulatory therapy in HP patients, especially if indices incorporating both distance and desaturation are used. Based on the present study results, we recommend 6MWD and DDI use, in addition to FVC and TL,co, to monitor treatment efficacy in patients with interstitial lung diseases.

The Role of Pulmonary Function Test for Pulmonary Arterial Hypertension in Patients with Connective Tissue Disease

Objective: The study aimed to investigate the value of pulmonary function test (PFT) in evaluating and predicting pulmonary arterial hypertension (PAH) in patients with connective tissue disease (CTD). Methods: This was a prospective observational study recruiting patients diagnosed with CTD-PAH. Patients with interstitial lung disease and pulmonary hypertension induced by other causes were not eligible for enrollment. All patients were assessed for PAH every 1–3 months. A patient was considered to have clinical improvement if the grade of risk stratification declined or at least two parameters improved during follow-up, otherwise no improvement. Results: A total of 31 patients with CTD-PAH were recruited in this study. Nearly 70% of patients had declined forced vital capacity (FVC), 60% had declined total lung capacity and maximum expiratory flow at 50% of vital capacity, and 95% had normal or mild decline in forced expiratory volume in 1 second (FEV1)/FVC. A decline in diffusing capacity of the lung for carbon monoxide (DLCO) was present in 96% of patients, and 60% were moderate to severe. Furthermore, 50% of patients had an FVC/DLCO ratio of less than 1.4. Univariate analysis showed that FEV1/FVC, DLCO, and FVC/DLCO were associated with disease prognosis. After adjusting for age as a confounding factor, multivariate logistic regression analysis revealed that DLCO was an independent predictive factor for the prognosis of CTD-PAH. Conclusion: The pulmonary function of patients with CTD-PAH is abnormal in parameters such as lung volume, small airway, and gas exchange. PFT can reveal complex pathophysiological changes in the lungs of CTD-PAH patients and predict prognosis.

A Nomogram for Predicting the Risk of Pulmonary Hypertension for Patients with Chronic Obstructive Pulmonary Disease

Background

Pulmonary hypertension (PH) is a life-threatening complication of chronic obstructive pulmonary disease (COPD). Timely diagnosis of PH in COPD patients is vital to achieve proper treatment; however, there is no algorithm to identify those at high risk. We aimed to develop a predictive model for PH in patients with COPD that provides individualized risk estimates.

Methods

A total of 527 patients with COPD who were admitted to our hospital between May 2019 and December 2020 were retrospectively enrolled in this study. Using echocardiographic results as a standard, patients were stratified into a moderate- or high-PH probability group and a low-PH probability group. They were randomly grouped into either the training set (n = 368 patients) or validation set (n = 159 patients) in a ratio of 7:3. We utilized the least absolute shrinkage and selection operator (LASSO) regression model to select the feature variables. The characteristic variables selected in the LASSO regression were analyzed using multivariable logistic regression to construct the predictive model. The predictive model was displayed using a nomogram. We used the receiver operating characteristic curve, calibration curve, and clinical decision curve analysis (DCA) to evaluate model performance, and internal validation was assessed.

Results

The predictive factors included in the prediction model were Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, emphysema, PaCO₂, NT-pro-BNP, red blood cell (RBC) distribution width-standard deviation (RDW-SD), and neutrophil/lymphocyte ratio (NLR). The predictive model yielded an area under the curve (AUC) of 0.770 (95% confidence interval [CI], 0.719–0.820); in the internal validation, the AUC was 0.741 (95% CI, 0.659–0.823). The predictive model was well calibrated, and the DCA showed that the proposed nomogram had strong clinical applicability.

Conclusion

This study showed that a simple nomogram could be used to calculate the risk of PH in patients with COPD which can be useful for the individualized clinical management of COPD patients who may be occur with PH. Further studies need to be confirmed by larger sample sizes and validated in the stable COPD population.

Echocardiographic signs of pulmonary hypertension in patients with newly recognized hypersensitivity pneumonitis, prevalence and clinical predictors

Background

Hypersensitivity pneumonitis (HP) is the third, according to frequency, interstitial lung disease, with the estimated incidence rate of 1–2/100,000. In HP patients, the extensive inflammatory lesions encompassing both small airways and lung parenchyma, as well as subsequent development of lung fibrosis, may result in respiratory insufficiency and secondary pulmonary hypertension (PH). The aim of the present retrospective study was to assess the prevalence of echocardiographic signs of PH and its’ clinical predictors, in newly recognized HP patients.

Methods

Consecutive HP patients, recognized in single pulmonary unit between 2005 and 2017, in whom echocardiography was performed at diagnosis, entered the present study. HP diagnosis was verified in every patient according to current diagnostic recommendations. The results of high resolution computed tomography of the chest (HRCT) were re-evaluated by two independent radiologists, blinded to clinical data. Echocardiographic signs of PH were defined as pulmonary artery systolic pressure (PASP) exceeding 36 mmHg. Regression analysis was applied to calculate PH risk, and receiver operator characteristic curves (ROC) were plotted to investigate diagnostic utility of various parameters in PH prediction.

Results

PASP exceeding 36 mmHg was noted in 26 out of 70 patients (37%)—with equal frequency among patients with fibrotic and non-fibrotic HP. Significant predictors of PH on echocardiography were: partial oxygen tension in arterialized capillary blood (PaO2) <69 mmHg, lung transfer capacity for carbon monoxide (TLCO) <42% of predicted, six minutes walking test (6MWT) distance <455 meters, and 6MWT desaturation rate >8%. In case of TLCO <42% of predicted, probability of PH on echocardiography was increased by five-fold, in case of 6MWT desaturation rate >8%—by four fold.

Conclusions

The best predictors of PASP >36 mmHg on echocardiography in HP patients at diagnosis were: TLCO <42% and 6MWT desaturation rate >8%. Neither the presence of lung fibrosis on HRCT, nor the duration of the disease or patients age, were helpful in PH prediction.