Mild elevation of pulmonary vascular resistance predicts mortality regardless of mean pulmonary artery pressure in mild interstitial lung disease

BACKGROUND

Pulmonary hypertension (PH) is defined by elevated mean pulmonary arterial pressure (MPAP), and elevated pulmonary vascular resistance (PVR) reflects pulmonary vascular abnormalities. The clinical significance of non-severe PH in patients with various interstitial lung diseases (ILDs) has not been fully elucidated. We aimed to investigate the clinical significance of MPAP and PVR for mortality in patients with newly diagnosed ILD.

METHODS

We retrospectively analysed consecutive patients with ILD at initial evaluations that included right heart catheterisation from 2007 to 2018. These patients were classified by MPAP and PVR using the 2022 the European Society of Cardiology (ESC)/the European Respiratory Society (ERS) guidelines for PH. The clinical significance of MPAP and PVR for mortality was analysed.

RESULTS

Among 854 patients, 167 (19.6%) had MPAP>20 mm Hg. The proportion of patients with PVR>2 Wood units (WU) among those with MPAP≤20 mm Hg, 202 WU was associated with a higher mortality rate (HR 1.61, 95% CI 1.28 to 2.02, p<0.0001) even in a group with MPAP≤20 mm Hg.

CONCLUSIONS

Mild elevation of PVR was associated with a higher mortality rate in patients with newly diagnosed ILD, even in those with MPAP≤20 mm Hg.

Pulmonary hypertension survival and hospitalisations in people living with HIV: a systematic review and meta-analysis

INTRODUCTION

People living with HIV (PLHIV) have a higher risk of developing pulmonary hypertension (PH) with subsequent poorer prognosis. This review aimed to determine the (1) survival outcomes and (2) proportion of emergency department (ED) visits and hospitalisations of PLHIV and PH.

METHODS

We conducted a systematic review and meta-analysis of observational studies reporting survival outcomes for PLHIV and PH. Electronic databases (Medline, EMBASE, PubMed, Web of Science, Global Index Medicus and Cochrane Library), trial registries and conference proceedings were searched until 22 July 2023. We pooled similar measures of effect, assessed apriori subgroups and used meta-regression to determine mortality and associated variables.

RESULTS

5248 studies were identified; 28 studies were included with a total of 5459 PLHIV and PH. The mean survival (95% CI) of PLHIV and PH was 37.4 months (29.9 to 44.8). Participants alive at 1, 2 and 3 years were 85.8% (74.1% to 95.0%), 75.2% (61.9% to 86.7%) and 61.9% (51.8% to 71.6%), respectively. ED visits and hospitalisation rates were 73.3% (32.5% to 99.9%) and 71.2% (42.4% to 94.2%), respectively. More severe disease, measured by echocardiogram, was associated with poorer prognosis (β -0.01, 95% CI -0.02 to 0.00, p=0.009). Survival was higher in high-income countries compared with lower-income countries (β 0.50, 95% CI 0.28 to 0.73, p<0.001) and in Europe compared with the America (β 0.56, 95% CI 0.37 to 0.75, p<0.001).

CONCLUSION

Our study confirms poor prognosis and high healthcare utilisation for PLHIV and PH. Prognosis is associated with country income level, geographic region and PH severity. This highlights the importance of screening in this population.

PROSPERO REGISTRATION NUMBER

CRD42023395023.

Inhaled treprostinil in patients with pulmonary hypertension associated with interstitial lung disease with less severe haemodynamics: a post hoc analysis of the INCREASE study

BACKGROUND

Inhaled treprostinil (iTre) is the only treatment approved for pulmonary hypertension due to interstitial lung disease (PH-ILD) to improve exercise capacity. This post hoc analysis evaluated clinical worsening and PH-ILD exacerbations from the 16-week INCREASE study and change in 6-minute walking distance (6MWD) in the INCREASE open-label extension (OLE) in patients with less severe haemodynamics.

METHODS

Patients were stratified by baseline pulmonary vascular resistance (PVR) of <4 Wood units (WU) versus ≥4 WU and <5 WU versus ≥5 WU. Exacerbations of underlying lung disease, clinical worsening and change in N-terminal prohormone of brain natriuretic peptide (NT-proBNP) in INCREASE were evaluated. For the OLE, patients previously assigned to placebo were considered to have a 16-week treatment delay. 6MWD and clinical events in the OLE were evaluated by PVR subgroup.

RESULTS

Of the 326 patients enrolled in INCREASE, patients with less severe haemodynamics receiving iTre had fewer exacerbations of underlying lung disease and clinical worsening events. This was supported by the Bayesian analysis of the risk of disease progression (HR<1), and significant decreases in NT-proBNP levels. In the OLE, patients without a treatment delay had improved exercise capacity after 1-year compared with those with a 16-week treatment delay (22.1 m vs -10.3 m). Patients with a PVR of ≤5 WU without a treatment delay had a change of 5.5 m compared with -8.2 m for those with a treatment delay. Patients without a treatment delay had a prolonged time to hospitalisation, lung disease exacerbation and death.

CONCLUSION

Treatment with iTre led to consistent benefits in clinical outcomes in patients with PH-ILD and less severe haemodynamics. Earlier treatment in less severe PH-ILD may lead to better exercise capacity long-term, however, the subgroup analyses in this post hoc study were underpowered and confirmation of these findings is needed.

Sendaway capillary NT-proBNP in pulmonary hypertension

BACKGROUND

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a biomarker of cardiac ventricular wall stress that is incorporated into pulmonary hypertension (PH) risk stratification models. Sendaway sampling may enable patients to perform NT-proBNP tests remotely. This UK-wide study aimed to assess the agreement of sendaway NT-proBNP with standard venous NT-proBNP and to assess the effect of delayed processing.

METHODS

Reference venous NT-proBNP was collected from PH patients. Samples for capillary and venous sendaway tests were collected contemporaneously, mailed to a reference laboratory and processed at 3 and 7 days using a Roche Cobas e411 device. Differences in paired measurements were analysed with Passing-Bablok regression, percentage difference plots and the % difference in risk strata.

RESULTS

113 patients were included in the study. 13% of day 3 capillary samples were insufficient. Day 3 capillary samples were not equivalent to reference samples (Passing Bablok analysis slope of 0.91 (95% CI 0.88 to 0.93) and intercept of 6.0 (95% CI 0.2 to 15.9)). The relative median difference was -7% and there were acceptable limits of agreement. Day 3 capillary NT-proBNP accurately risk stratified patients in 93.5% of cases. By comparison, day 3 venous results accurately risk stratified patients in 90.1% of cases and were equivalent by Passing-Bablok regression. Delayed sampling of sendaway tests led to an unacceptable level of agreement and systematically underestimated NT-proBNP.

CONCLUSIONS

Sendaway NT-proBNP sampling may provide an objective measure of right ventricular strain for virtual PH clinics. Results must be interpreted with caution in cases of delayed sampling.

Survival analysis from the INCREASE study in PH-ILD: evaluating the impact of treatment crossover on overall mortality

OBJECTIVE

A post-hoc analysis of the INCREASE trial and its open-label extension (OLE) was performed to evaluate whether inhaled treprostinil has a long-term survival benefit in patients with pulmonary hypertension associated with interstitial lung disease (PH-ILD).

METHODS

Two different models of survival were employed; the inverse probability of censoring weighting (IPCW) and the rank-preserving structural failure time (RPSFT) models both allow construction of a pseudo-placebo group, thereby allowing for long-term survival evaluation of patients with PH-ILD receiving inhaled treprostinil. Time-varying stabilised weights were calculated by fitting Cox proportional hazards models based on the baseline and time-varying prognostic factors to generate weighted Cox regression models with associated adjusted HRs.

RESULTS

In the INCREASE trial, there were 10 and 12 deaths in the inhaled treprostinil and placebo arms, respectively, during the 16-week randomised trial. During the OLE, all patients received inhaled treprostinil and there were 29 and 33 deaths in the prior inhaled treprostinil arm and prior placebo arm, respectively. With a conventional analysis, the HR for death was 0.71 (95% CI 0.46 to 1.10; p=0.1227). Both models demonstrated significant reductions in death associated with inhaled treprostinil treatment with HRs of 0.62 (95% CI 0.39 to 0.99; p=0.0483) and 0.26 (95% CI 0.07 to 0.98; p=0.0473) for the IPCW and RPSFT methods, respectively.

CONCLUSION

Two independent modelling techniques that have been employed in the oncology literature both suggest a long-term survival benefit associated with inhaled treprostinil treatment in patients with PH-ILD.

Vasoactive drugs for the treatment of pulmonary hypertension associated with interstitial lung diseases: a systematic review

OBJECTIVES

Vasoactive drugs have exhibited clinical efficacy in addressing pulmonary arterial hypertension, manifesting a significant reduction in morbidity and mortality. Pulmonary hypertension may complicate advanced interstitial lung disease (PH-ILD) and is associated with high rates of disability, hospitalisation due to cardiac and respiratory illnesses, and mortality. Prior management hinged on treating the underlying lung disease and comorbidities. However, the INCREASE trial of inhaled treprostinil in PH-ILD has demonstrated that PH-ILD can be effectively treated with vasoactive drugs.

METHODS

This comprehensive systematic review examines the evidence for vasoactive drugs in the management of PH-ILD.

RESULTS

A total of 1442 pubblications were screened, 11 RCTs were considered for quantitative synthesis. Unfortunately, the salient studies are limited by population heterogeneity, short-term follow-up and the selection of outcomes with uncertain clinical significance.

CONCLUSIONS

This systematic review underscores the necessity of establishing a precision medicine-oriented strategy, directed at uncovering and addressing the intricate cellular and molecular mechanisms that underlie the pathophysiology of PH-ILD.

PROSPERO REGISTRATION NUMBER

CRD42023457482.

Methamphetamine-associated pulmonary arterial hypertension: data from the national biological sample and data repository for pulmonary arterial hypertension (PAH Biobank)

OBJECTIVE

This study compares the clinical and haemodynamic severity of methamphetamine-associated pulmonary arterial hypertension (MA-PAH) with idiopathic pulmonary arterial hypertension (IPAH) and connective tissue-associated pulmonary arterial hypertension (CTD-PAH). It also examines sex differences in clinical and physiological parameters among those with MA-PAH.

DESIGN

This is a cross-sectional study using clinically derived data from the National Biological Sample and Data Repository for Pulmonary Arterial Hypertension (PAH biobank), a US-based registry, to compare clinical and physiological characteristics between males and females with MA-PAH.

POPULATION

The analysis included 1830 patients enrolled in the PAH biobank, with a diagnosis of MA-PAH (n=42), IPAH (n=1073), or CTD-PAH (n=715).

MAIN OUTCOME MEASURES

The study assessed and compared the clinical and haemodynamic parameters of patients with MA-PAH, IPAH and CTD-PAH.

RESULTS

Among the patients analysed, 42 had MA-PAH, with 69.1% being female. There were no statistically significant differences in functional class among patients with MA-PAH, IPAH and CTD-PAH. The per cent predicted 6-min walk distance (6MWD) was comparable between the three groups. Patients with MA-PAH had similar mean pulmonary artery pressure and pulmonary vascular resistance to patients with IPAH but higher compared with patients with CTD-PAH. Male patients with MA-PAH exhibited a worse functional class and lower per cent predicted 6MWD, but no significant differences in haemodynamic findings were observed between the sexes.

CONCLUSION

There were no differences in haemodynamic between MA-PAH and IPAH but we found that MA-PAH differed from CTD-PAH. The study did not find evidence of sex differences in MA-PAH. Further research is necessary to identify risk factors and underlying mechanisms of MA-PAH, particularly considering the increasing prevalence of methamphetamine use. Such investigations will contribute to the development of effective prevention and treatment strategies for this condition.

Patients' perceptions on clinical trials outcomes in pulmonary arterial hypertension therapy

The value placed by patients and their caregivers on the components of composite outcomes in pulmonary arterial hypertension (PAH) remains unknown. We surveyed the importance of these outcomes from a patients' and caregivers' perspective, with participants (n=335, including 257 patients with PAH) rating individual components defining clinical worsening in PAH trials as of critical, major, mild-to-moderate or minor importance. Most outcomes were considered of major or mild-to-moderate importance to patients. Death was the only outcome considered of critical importance. Perceptions of clinical outcomes varied between patients and caregivers. Integrating patients' perception in the elaboration of clinical trials is essential.

Thyroid-stimulating hormone and mortality in pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) remains a serious and life-threatening illness. Thyroid dysfunction is relatively understudied in individuals with PAH but is known to affect cardiac function and vascular tone in other diseases. The aim of this observational study was to evaluate the association between thyroid-stimulating hormone (TSH), mortal and non-mortal outcomes in individuals with PAH.

METHODS

The Seattle Right Ventricle Translational Science (Servetus) Study is an observational cohort that enrolled participants with PAH between 2014 and 2016 and then followed them for 3 years. TSH was measured irrespective of a clinical suspicion of thyroid disease for all participants in the cohort. Linear regression was used to estimate the relationships between TSH and right ventricular basal diameter, tricuspid annular plane systolic excursion and 6-minute walk distance. Logistic regression was used to estimate the relationship with New York Heart Association Functional Class, and Cox proportional hazards were used to estimate the relationship with mortality. Staged models included unadjusted models and models accounting for age, sex at birth and aetiology of pulmonary hypertension with or without further adjustment for N-terminal-pro hormone brain natriuretic peptide.

RESULTS

Among 112 participants with PAH, TSH was strongly associated with mortality irrespective of adjustment. There was no clear consistent association between TSH and other markers of severity in a cohort with PAH.

DISCUSSION

This report reinforces the important observation that TSH is associated with survival in patients with PAH, and future study of thyroid dysfunction as a potential remediable contributor to mortality in PAH is warranted.

Incidence and outcomes of pulmonary hypertension in the Ireland

INTRODUCTION

Pulmonary hypertension (PH) is a progressive disease of the pulmonary vasculature, which is characterised by premature morbidity and mortality. The aim of this study is to define the characteristics of PH in the national PH unit (NPHU) in Ireland between 2010 and 2020.

METHODS

Cases of PH which were referred to the NPHU between 2010 and 2020 were included. PH was defined as a mean pulmonary artery pressure ≥25 mm Hg at right heart catheterisation.

RESULTS

Four hundred and fifteen cases of PH were identified during the study period. Group 1 pulmonary arterial hypertension (PAH) accounted for 39% (n=163) of cases, with a calculated annual incidence of 3.11 per million population (95% CI 1.53 to 4.70). The leading PAH subgroup was connective tissue disease-associated PAH (CTD-PAH), which was responsible for 49% of PAH referrals. This was followed by idiopathic PAH, with an estimated annual incidence of 0.63 cases per million population. The mean age at PAH diagnosis was 56±15 years and 86% (n=111) received double-combination or triple-combination therapy within the first 12 months of diagnosis. The 1-year, 3-year and 5-year transplant-free survival for PAH was 89%, 75% and 65%. This was significantly lower for individuals with CTD-PAH relative to other PAH subgroups (p<0.05).

DISCUSSION

This study describes the incidence and outcomes of PH in Ireland. While the outcomes are comparable to other centres, the incidence of PAH and specific subgroups appears low, suggesting that improved disease awareness and case recognition are required. Furthermore, the survival of individuals with CTD-PAH is poor and requires additional exploration.

Combining creative writing and narrative analysis to deliver new insights into the impact of pulmonary hypertension

INTRODUCTION

Pulmonary hypertension is life limiting. Delays in diagnosis are common, and even after treatment has been initiated, pulmonary hypertension has marked effects on many aspects of social and physical function. We believed that a new approach to examining disease impact could be achieved through a combination of narrative research and creative writing.

METHODS

Detailed unstructured narrative interviews with people with pulmonary hypertension were analysed thematically. Individual moments were also summarised and studied using creative writing, in which the interviewer created microstories from narrative and interview data. Stories were shared with their subjects, and with other patients, clinicians, researchers and the wider public. The study was carried out in hospital and in patients' homes.

RESULTS

Narrative analysis generated a rich data set which highlighted profound effects of pulmonary hypertension on identity, and demonstrated how the disease results in very marked personal change with ongoing and unpredictable requirement for adaptation. The novel methodology of microstory development proved to be an effective tool to summarise, communicate and explore the consequences of pulmonary hypertension and the clinical challenges of caring for patients with this illness.

CONCLUSIONS

A holistic approach to treatment of chronic respiratory diseases such as pulmonary hypertension requires and benefits from explicit exploration of the full impacts of the illness. Narrative analysis and the novel approach of targeted microstory development can form a valuable component of the repertoire of approaches to effectively comprehend chronic disease and can also facilitate patient-focused discussion and interventions.

The molecular targets of approved treatments for pulmonary arterial hypertension

Until recently, three classes of medical therapy were available for the treatment of pulmonary arterial hypertension (PAH)--prostanoids, endothelin receptor antagonists and phosphodiesterase type 5 (PDE5) inhibitors. With the approval of the soluble guanylate cyclase stimulator riociguat, an additional drug class has become available targeting a distinct molecular target in the same pathway as PDE5 inhibitors. Treatment recommendations currently include the use of all four drug classes to treat PAH, but there is a lack of comparative data for these therapies. Therefore, an understanding of the mechanistic differences between these agents is critical when making treatment decisions. Combination therapy is often used to treat PAH and it is therefore important that physicians understand how the modes of action of these drugs may interact to work as complementary partners, or potentially with unwanted consequences. Furthermore, different patient phenotypes mean that patients respond differently to treatment; while a certain monotherapy may be adequate for some patients, for others it will be important to consider alternating or combining compounds with different molecular targets. This review describes how the four currently approved drug classes target the complex pathobiology of PAH and will consider the distinct target molecules of each drug class, their modes of action, and review the pivotal clinical trial data supporting their use. It will also discuss the rationale for combining drugs (or not) from the different classes, and review the clinical data from studies on combination therapy.

CT features of pulmonary arterial hypertension and its major subtypes: a systematic CT evaluation of 292 patients from the ASPIRE Registry

We evaluated the prevalence and prognostic value of CT-pulmonary angiographic (CTPA) measures in 292 treatment naive patients with pulmonary arterial hypertension (PAH). Pulmonary artery calcification (13%) and thrombus (10%) were exclusively seen in PAH-congenital heart disease. Oesophageal dilation (46%) was most frequent in PAH-systemic sclerosis. Ground glass opacification (GGO) (41%), pericardial effusion (38%), lymphadenopathy (19%) and pleural effusion (11%) were common. On multivariate analysis, inferior vena caval area, the presence of pleural effusion and septal lines predicted outcome. In PAH, CTPA provides diagnostic and prognostic information. In addition, the presence of GGO on a CT performed for unexplained breathlessness should alert the physician to the possibility of PAH.

Changes in right heart haemodynamics and echocardiographic function in an advanced phenotype of pulmonary hypertension and right heart dysfunction associated with pulmonary fibrosis

BACKGROUND

Pulmonary hypertension (PH)-targeted therapy in the setting of pulmonary fibrosis (PF) is controversial; the main clinical concern is worsening of systemic hypoxaemia. We sought to determine the effects of gentle initiation and chronic administration of parenteral treprostinil on right heart function in patients with PF associated with an advanced PH phenotype.

METHODS

Open-label, prospective analysis of patients with PF-PH referred for lung transplantation (LT). Advanced PH was defined as mean pulmonary artery pressure (mPAP) ≥35 mm Hg. We compared haemodynamics, Doppler echocardiography (DE), oxygenation, dyspnoea and quality of life indices, and 6 min walk distance (6MWD) before and 12 weeks after parenteral treprostinil.

RESULTS

15 patients were recruited in the study. After therapy, there were significant improvements in right heart haemodynamics (right atrial pressure (9.5 ± 3.4 vs 6.0 ± 3.7); mPAP (47 ± 8 vs 38.9 ± 13.4); CI (2.3 ± 0.5 vs 2.7 ± 0.6); pulmonary vascular resistance (698 ± 278 vs 496 ± 229); transpulmonary gradient (34.7 ± 8.7 vs 28.5 ± 10.3); mvO2 (65 ± 7.2 vs 70.9 ± 7.4); and stroke volume index (29.2 ± 6.7 vs 33 ± 7.3)) and DE parameters reflecting right heart function (right ventricular (RV) end diastolic area (36.4 ± 5.2 vs 30.9 ± 8.2 cm(2)), left ventricular eccentricity index (1.7 ± 0.6 vs 1.3 ± 0.5), tricuspid annular planar systolic excursion (1.6 ± 0.5 vs 1.9 ± 0.2 cm)). These changes occurred without significant alteration in systemic oxygenation, heart rate, or mean systemic arterial pressure. In addition, improvements were seen in 6MWD (171 ± 93 vs 230 ± 114), 36-Item Short Form Health Survey Mental Component Summary aggregate (38 ± 11 vs 44.2 ± 10.7), University of California, San Diego Shortness of Breath Questionnaire (87 ± 17.1 vs 73.1 ± 21), and brain natriuretic peptide (558 ± 859 vs 228 ± 340).

CONCLUSIONS

PH-targeted therapy may improve right heart haemodynamics and echocardiographic function without affecting systemic oxygen saturation in an advanced PH phenotype associated with RV dysfunction in the setting of PF.

Surgical specimens, haemodynamics and long-term outcomes after pulmonary endarterectomy

Background

Chronic thromboembolic pulmonary hypertension is surgically curable by pulmonary endarterectomy (PEA). It is unclear whether PEA impacts primarily steady state right ventricular afterload (ie, pulmonary vascular resistance (PVR)) or pulsatile right ventricular afterload (ie, pulmonary arterial compliance (C_PA)). Our objectives were to (1) quantify PEA specimens and measure the impact of PEA on PVR and C_PA in a structure/function study and (2) analyse the effects of haemodynamic changes on long-term survival/freedom of lung transplantation in an outcome study.

Methods

Thrombi were laid out, weighed, photographed and measured. PVR, C_PA and resistance times compliance (RC-time) were assessed at baseline, within 4 days after PEA (‘immediately postoperative’) and 1 year after PEA, in 110 consecutive patients who were followed for 34.5 (11.9; 78.3) months.

Results

Lengths and numbers of PEA specimen tails were inversely correlated with immediate postoperative PVR (p<0.0001, r=−0.566; p<0.0001, r=−0.580). PVR and C_PA normalised immediately postoperatively while RC-time remained unchanged. Immediate postoperative PVR was the only predictor of long-term survival/freedom of lung transplantation (p<0.0001). Patients with immediate postoperative PVR<590 dynes.s.cm⁻⁵ had better long-term outcomes than patients with PVR≥590 dynes.s.cm⁻⁵ (p<0.0001, respectively).

Conclusions

PEA immediately decreased PVR and increased C_PA under a constant RC-time. However, immediate postoperative PVR was the only predictor of long-term survival/freedom of lung transplantation. Our study confirms the importance of a complete, bilateral surgical endarterectomy. Low PVR measured immediately postoperative predicts excellent long-term outcome.