Pulmonary Capillary Hemangiomatosis as a Rare Underlying Cause of Primary Pulmonary Hypertension: A Case Report in an Adolescent.

Despite its rarity, pulmonary capillary hemangiomatosis (PCH) presents a significant diagnostic challenge. Due to its similarity to other pulmonary vascular diseases, such as pulmonary veno-occlusive disease, it is characterized by abnormal pulmonary capillary proliferation, which is a rare cause of primary pulmonary hypertension. This case was the first reported instance of PCH in Shahid Rajaee Heart Hospital in Tehran, Iran, in 2023, which was confirmed by genetic testing. It highlighted the importance of considering PCH among the differential diagnoses for pulmonary hypertension, even in adolescent patients. The 13-year-old patient's main complaints were progressive exertional dyspnea and chest pain. He had no previous medical history and had not taken any pharmaceutical or herbal medications. Critical clinical findings included a heart murmur, an electrocardiogram revealing right ventricular hypertrophy, and echocardiogram evidence of pulmonary hypertension. The main diagnosis was PCH, as shown by CT findings of pulmonary artery dilatation and diffuse nodular ground glass opacities. Genetic tests indicated pathogenic EIF2AK4 mutations and suspicion of PCH. Therapeutic intervention included vasodilator therapy, which exacerbated the patient's condition. This case emphasized the importance of maintaining a high index of suspicion for rare causes of pulmonary hypertension, such as PCH. The outcome was to prepare the patient for lung transplantation. To differentiate PCH from other pulmonary vascular diseases, a combination of clinical presentation, radiologic studies, genetic analysis, and response to treatment is required to determine appropriate management, particularly lung transplantation.

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 (ß -0.01, 95% CI -0.02 to 0.00, p=0.009). Survival was higher in high-income countries compared with lower-income countries (ß 0.50, 95% CI 0.28 to 0.73, p<0.001) and in Europe compared with the America (ß 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.

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.

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.

Escalating Oral Treprostinil Dose With Intravenous Treprostinil Bridging Therapy.

Oral treprostinil, approved for the treatment of pulmonary arterial hypertension, remains an attractive option in combination with other medications to delay disease progression and improve exercise capacity. However, patients are often challenged with the ability to overcome adverse effects as outpatients and reach effective doses in a timely manner. We describe a case of a 47-year-old female on oral treprostinil who presented to the clinic with worsening symptoms of disease, necessitating higher dosing. This patient was previously uptitrated outpatient with oral treprostinil, which had allowed her to remain stable for years. Once uptitrated with additional intravenous therapy, the oral treprostinil dose was gradually further increased to the new goal dosage, resulting in improvements in symptoms and right ventricular function. This case highlights the versatility of dose optimization of oral treprostinil with rapid bridging through intravenous therapy.

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.

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.

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.

Exercised-based cardiac rehabilitation associates with lower all-cause mortality in patients with primary pulmonary hypertension.

Background: Despite pharmacological therapies to improve outcomes of pulmonary hypertension (PH), poor long-term survival remains. Exercised-based cardiac rehabilitation (ExCR) may be an alternative strategy to improve prognosis. Therefore, using an electronic medical record (EMR) database, the objective of this study was to compare mortality between patients with primary PH with ExCR vs. propensity-matched PH patients without ExCR. Methods: The retrospective analysis was conducted on February 15, 2023 using anonymized data within TriNetX, a global federated health research network. All patients were aged ≥18 years with primary PH recorded in EMRs with at least 1-year follow-up from ExCR. Using logistic regression models, patients with PH with an EMR of ExCR were 1:1 propensity score-matched with PH patients without ExCR for age, sex, race, and comorbidities, and cardiovascular care. Results: In total, 109,736 patients with primary PH met the inclusion criteria for the control group and 784 patients with primary PH met the inclusion criteria for the ExCR cohort. Using the propensity score-matched cohorts, 1-year mortality from ExCR was proportionally lower with 13.6% (n = 101 of 744 patients) in the ExCR cohort compared to 23.3% (n = 174 of 747 patients) in the controls (OR 0.52, 95% CI 0.40-0.68). Conclusion: The present study of 1,514 patients with primary PH suggests that ExCR is associated with 48% lower odds of 1-year mortality, when compared to propensity score-matched patients without ExCR.

Right ventricular functional recovery assessment with stress echocardiography and cardiopulmonary exercise testing after pulmonary embolism: a pilot prospective multicentre study.

BACKGROUND: Data on right ventricular (RV) exercise adaptation following acute intermediate and high-risk pulmonary embolism (PE) remain limited. This study aimed to evaluate the symptom burden, RV functional recovery during exercise and cardiopulmonary exercise parameters in survivors of intermediate and high-risk acute PE. METHODS: We prospectively recruited patients following acute intermediate and high-risk PE at four sites in Australia and UK. Study assessments included stress echocardiography, cardiopulmonary exercise testing (CPET) and ventilation-perfusion (VQ) scan at 3 months follow-up. RESULTS: Thirty patients were recruited and 24 (median age: 55 years, IQR: 22) completed follow-up. Reduced peak oxygen consumption (VO2) and workload was seen in 75.0% (n=18), with a persistent high symptom burden (mean PEmb-QoL Questionnaire 48.4±21.5 and emPHasis-10 score 22.4±8.8) reported at follow-up. All had improvement in RV-focused resting echocardiographic parameters. RV systolic dysfunction and RV to pulmonary artery (PA) uncoupling assessed by stress echocardiography was seen in 29.2% (n=7) patients and associated with increased ventilatory inefficiency (V̇E/V̇CO2 slope 47.6 vs 32.4, p=0.03), peak exercise oxygen desaturation (93.2% vs 98.4%, p=0.01) and reduced peak oxygen pulse (p=0.036) compared with controls. Five out of seven patients with RV-PA uncoupling demonstrated persistent bilateral perfusion defects on VQ scintigraphy consistent with chronic thromboembolic pulmonary vascular disease. CONCLUSION: In our cohort, impaired RV adaptation on exercise was seen in almost one-third of patients. Combined stress echocardiography and CPET may enable more accurate phenotyping of patients with persistent symptoms following acute PE to allow timely detection of long-term complications.

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.

Review of the British Thoracic Society Winter Meeting 23 November 2022 23-25 November 2022.

The British Thoracic Society Winter Meeting at the QEII Centre in London provided the first opportunity for the respiratory community to meet and disseminate research findings face to face since the start of the COVID-19 pandemic. World-leading researchers from the UK and abroad presented their latest findings across a range of respiratory diseases. This article aims to represent the range of the conference and as such is written from the perspective of a basic scientist, a physiotherapist and two doctors. The authors reviewed showcase sessions plus a selection of symposia based on their personal highlights. Content ranged from exciting new developments in basic science to new and unpublished results from clinical trials, delivered by leading scientists from their fields including former deputy chief medical officer Professor Sir Jonathan Van-Tam and former WHO chief scientist Dr Soumya Swaminathan.

Management of Idiopathic Pulmonary Arterial Hypertension in a Patient in Trinidad: A Case Report.

Abnormal elevation in pulmonary arterial blood pressure without secondary causes is Idiopathic Pulmonary Arterial Hypertension (IPAH). It is imperative to establish this diagnosis because IPAH often progresses to right heart failure (RHF) and death without treatment. Right heart catheterization is the standard gold test for diagnosing pulmonary hypertension (PH); however, echocardiography is a susceptible sensitive test and the best non-invasive test. The overall management of IPAH involves supportive measures, conventional therapy, and, pending availability, PAH-targeted therapy. Upon review of the literature, there were no published case reports on IPAH in Trinidad and Tobago. We describe a case of IPAH presented at Apley Medical Centre Limited, Trinidad and Tobago, in the West Indies, emphasizing contemporary management, including using the Implantable Delivery Systems (IDS) for Remodulin injection.

Comparison of obstructive sleep apnoea prevalence and severity across WHO pulmonary hypertension groups.

INTRODUCTION: Pulmonary hypertension is classified into five groups in the WHO classification system. Patients with pulmonary hypertension often have comorbid obstructive sleep apnoea (OSA), yet the prevalence and severity of OSA in each of the WHO pulmonary hypertension groups have not been well established. METHODS: To compare the prevalence and severity of OSA between WHO pulmonary hypertension groups, we performed a retrospective cohort study, including patients who had polysomnography or a home sleep study and confirmed pulmonary hypertension on right heart catheterisation. The primary outcomes of OSA prevalence and severity were measured by median apnoea hypopnea index (AHI) or respiratory event index (REI) and were compared by WHO pulmonary hypertension group. Multivariable negative binomial regression was used to evaluate the association between the outcome of OSA severity by AHI or REI and WHO group. RESULTS: Among the cohort of 132 patients, OSA was common in all WHO pulmonary hypertension groups but was most common and most severe in WHO group II pulmonary hypertension. Median AHI or REI in WHO group II was 12.0 events/hour compared with 2.8 in group I, 3.7 in group III, 10.0 in group IV and 6.4 in group V. Multivariable negative binomial regression showed about a twofold increase in AHI or REI in WHO group II compared with WHO group I pulmonary hypertension. DISCUSSION: Our findings demonstrate that OSA deserves greater consideration as a treatable comorbidity that may affect pulmonary haemodynamics and quality of life in patients with pulmonary hypertension across all WHO groups.

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.

Abnormal Liver Function Tests Were Related to Short- and Long-Term Prognosis in Critically Ill Patients With Primary Pulmonary Hypertension.

Aim: The aim of this study was to examine the utility of liver function tests (LFTs) in predicting the prognosis of critically ill patients with primary pulmonary hypertension (PPH) with/without liver disease. Methods: We retrieved the Medical Information Mart for Intensive Care III (MIMIC-III) database to acquire clinical data. From the database, we recruited adult patients that were equal to or older than 18 years with primary pulmonary hypertension (PPH) discharge from intensive care unit (ICU). Then, the relationship between LFTs and duration of hospitalization and ICU stays was examined based on the Spearman correlation. The chi-square assessment was conducted to examine the correlation between LFTs and death rates. Survival curves were plotted with the aid of the Kaplan-Meier technique, and the curves were subsequently compared utilizing the log-rank test. The LFTs were identified as independent predictive variables of death according to the results of multivariable logistic regression. The specificity and sensitivity for mortality were calculated utilizing receiver operating characteristic (ROC) curves and the area under the curve (AUC). Results: In total, 198 patients satisfying the inclusion criteria were recruited, among which there were 23 patients with liver disease. Only ALB was correlated with the length of ICU stay in the total PPH group. ALB independently served as a risk variable for hospital mortality and 90-day mortality and was significantly associated with 90-day and 4-year survival rates in both total PPH and PPH without liver disease. AST was correlated with hospital mortality and 90-day survival curves in both total PPH and PPH without liver disease and independently served as a risk factor for hospital and 90-day mortality only in the total PPH group. ALT independently acted as a risk variable for hospital mortality and total bilirubin was correlated with hospital mortality in the total group. The diagnostic performance of the predictive model combining the LFTs was moderately good for the hospital, 90-day, and 4-year mortality. Both Modeli End-Stage iLiveri Disease (MELD) score and albumin-bilirubin (ALBI) score were independent risk factors for short- and long-term prognosis. And they were also significantly associated with short- and long-term prognosis. Conclusion: Among critically ill patients with PPH and with or without liver illness, aberrant LFT was linked to short- and long-term prognoses.

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.