Frantz, Robert P.

Abstract Introduction Interstitial lung disease-associated pulmonary hypertension (ILD-PH) is a clinically challenging entity that lies on a pathophysiologic spectrum between pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD). We compared the metabolomes of patients with ILD-PH to those with PAH and ILD to characterize the PAH-ILD axis and determine whether ILD-PH patients can be phenotyped based on their metabolomic similarity to PAH. Methods Using untargeted metabolomics profiles from patients with PAH, ILD, and ILD-PH in the large, U.S.-based, NIH-funded, multi-center PVDOMICS cohort, we trained an anchor-based classifier on PAH and ILD metabolomes using supervised PLS-DA with a 75/25 train/test split. Primary and secondary PH or risk-group classifications in PVDOMICS were based on expert adjudication of clinical data including right heart catheterization hemodynamics, pulmonary function testing, chest imaging, and laboratory results. We then applied the trained model to each ILD-PH patient to assign a PAH similarity score. We classified patients as having a PAH-like or ILD-like metabolomic phenotype using an optimal PAH similarity score cutoff of 0.5 then compared PAH metabolomic similarity to expert-adjudicated primary and secondary WSPH classifications in PVDOMICS. We implemented FELLA, a network-based metabolomics enrichment method, to holistically characterize the biologic underpinnings of PAH, ILD-PH, and ILD metabolomes. Results We analyzed 244 patients with PAH, 54 with ILD, and 47 with ILD-PH. The anchor-based classifier demonstrated high train-test performance with a c-statistic of 0.81 and 78% agreement with expert-adjudicated diagnoses. Among the ILD-PH patients, 23 were classified as PAH-like and 24 as ILD-like (74% agreement with expert adjudication, Cohen’s kappa 0.49, Hedge’s g estimate of 0.86). FELLA enrichment revealed core glycolytic and bioenergetic pathways were enriched in both pure PAH and ILD-PH. Comparison of diffusion Z-scores between groups demonstrated subtle but biologically coherent differences in several reaction-level nodes, including lactate, NADPH oxidoreductase, and phosphofructokinase, which were enriched in ILD-PH. Conclusion Patients with ILD-PH demonstrate clinically relevant metabolomic phenotypes. Examination of the network biology underlying ILD-PH may point to potential therapeutic targets in this vulnerable subgroup with lagging clinical outcomes. This abstract is funded by: Pulmonary Fibrosis Foundation PFF Scholars Program

Abstract Rationale The pathophysiology and clinical impact of liver injury in pulmonary hypertension (PH) is poorly understood. Liver injury in PH is often attributed to hepatic congestion, but some studies have failed to find strong associations with hemodynamics, suggesting alternative mechanisms. We sought to define the prevalence of liver injury and patterns of liver injury across the spectrum of PH and to determine whether patterns of liver injury were associated with clinical characteristics, hemodynamics and outcomes. Methods We performed an analysis of the PVDOMICS study, a multicenter, prospective, longitudinal cohort study that enrolled incident and prevalent patients with PH and disease comparators. The prevalence of liver injury, defined as aspartate or alanine aminotransferase (AST or ALT) or total bilirubin above the upper limit of normal, and different patterns of liver injury [hepatocellular (elevated AST or ALT with normal bilirubin), cholestatic (elevated bilirubin) and no liver injury] was defined among participants with known or suspected PH. Associations between patterns of liver injury with demographics, hemodynamics, right ventricular function, exercise capacity and quality of life (QoL) were assessed. We used Cox proportional hazards models adjusted for age and sex to assess the association of liver injury patterns with transplant-free survival. Results Liver injury was present in 27.8% (288/1036) of participants (19.0% cholestatic and 8.8% hepatocellular). Patients with liver injury were less likely to be female and have prevalent disease with differences in PH classification (Table 1). Patients with hepatocellular liver injury had a higher body mass index. A cholestatic liver injury pattern was most consistently associated with worse functional class, biventricular filling pressures, pulmonary vascular resistance, right ventricular function, natriuretic peptide elevation, exercise capacity, and REVEAL risk scores. Total bilirubin levels and right atrial pressure as a marker of systemic congestion were weakly correlated (r2=0.02, p < 0.0001). Compared to no liver injury, cholestatic liver injury was associated with an increased risk of death in age and sex adjusted models (HR 1.6, 95% CI 1.3-2.1, p < 0.001) but hepatocellular liver injury was not (p > 0.05). Conclusions Liver injury is common among patients with known or suspected PH. In contrast to a hepatocellular injury pattern, a cholestatic liver injury pattern was most consistently associated with worse hemodynamics, exercise capacity, QoL and survival. However, the weak relationship between right atrial pressure and bilirubin suggests that systemic congestion alone is unlikely to completely explain cholestatic liver injury. Further study is needed to uncouple the pathophysiological basis of cholestasis in PH. This abstract is funded by: NHLBI

Abstract Rationale Sotatercept is a novel activin signaling inhibitor approved for the treatment of pulmonary arterial hypertension (PAH). Sotatercept has been studied in randomized clinical trials, but little is known regarding the real-world use of sotatercept. We sought to describe the safety, tolerability and efficacy of sotatercept in our clinical practice. Methods We performed a combined prospective and retrospective cohort study of all patients treated with sotatercept at Mayo Clinic Rochester since its approval in March 2024. Patients enrolled in a separate clinical trial of sotatercept were excluded from this analysis as their data will be reported separately. Clinical data was abstracted from the electronic health record. Follow-up data was collected at 6 ± 3 months after initiation of sotatercept. Data is summarized as n (%) and mean ± SD. We used paired t-tests to compare baseline and follow-up characteristics within individuals. Results Fifty-eight PAH patients treated with sotatercept were included. Patients were 48.4 ± 37.6 years old at treatment initiation and were predominantly female with a mean duration of PAH of 6.7 years and a range of PAH etiologies including portopulmonary hypertension, congenital heart disease, and pulmonary veno-occlusive disease (Table 1). Twenty-one (36%) of patients had mixed etiologies of PH. Six months after initiation of sotatercept, patients had a significant improvement in NTproBNP (1922 ± 4464 to 363 ± 596 pg/ml, p = 0.04), 6 minute walk distance (378.8 ±144.6 to 395.7±129.5 meters, p = 0.02) and right ventricular systolic pressure (74.6 ± 20.5 to 60.6 ± 20.3 mm Hg, p < 0.001). No patients permanently discontinued due to abnormal laboratory values. Mean highest hemoglobin achieved over the initial 6 months of treatment was 15.5 ± 2.1 g/dL and mean lowest platelet count was 181 ± 74K. Seven patients discontinued sotatercept at a range of 170-275 days after starting. Four patients discontinued due to possible treatment-related adverse effects: 1 each of gastrointestinal hemorrhage, retinal hemorrhage, hypoxia/intrapulmonary vasodilatation and spontaneous bilateral subdural hematomas. Three patients discontinued due to other reasons: newly diagnosed metastatic cancer leading to transition to hospice and two due to lack of improvement. Conclusions In this real-world registry of sotatercept in PAH, sotatercept was well-tolerated among patients with PAH and associated with improvements in exercise capacity, echocardiographic parameters, and NTproBNP. Overall discontinuation due to possible treatment-related adverse effects was low and reasons for discontinuation included bleeding and hypoxia attributed to intrapulmonary vasodilatation. This abstract is funded by: None

Abstract Rationale Prior studies demonstrate pulmonary artery (PA) enlargement on computed tomography (CT) in pulmonary hypertension (PH). Some patients exhibit markedly enlarged or “aneurysmal” PA dilation, but its clinical relevance remains unclear. We aimed to characterize clinical characteristics, hemodynamics, and survival probability of patients with aneurysmal PA size. Methods Demographics, clinical characteristics, and CT imaging were obtained for individuals with group 1 or 2 PH and matched controls in the Pulmonary Vascular Disease Phenomics cohort. PA diameter was measured using Osirix software. PA diameter was categorized based on previously reported values as normal (<27 mm [females], <29 mm [males]), enlarged (27-39 mm [females], 29-39 mm [males]), or aneurysmal (≥40 mm). Outcomes included mean PA pressure (mPAP) on right heart catheterization (RHC) and time to death or heart/lung transplant. Associations with mortality and mPAP were evaluated using multivariable Cox and linear regression models, adjusting for age, sex, and BMI. Descriptive statistics are presented as median [IQR]. Results 690 subjects met the inclusion criteria for survival analysis (364 WSPH group 1 or matched comparator, 241 group 2 or comparator, 85 healthy control), with 594 undergoing RHC. PA diameter was normal in 163 participants, enlarged in 414, and aneurysmal in 113. Aneurysmal PA, compared with normal or enlarged PA, was associated with younger age (53 ± 14 vs 55 ± 16 and 59 ± 15 years, respectively; p < 0.001), non-White race (18.9% vs 8% and 17.2%; p = 0.034), pro-BNP (1950 ± 5708 vs 531 ±1651 and 110 ± 2258 pg/mL; p < 0.001), PH duration (6.78 ± 6.86 vs 2.24 ± 4.39 and 3.82 ± 5.47 years; p < 0.001), group 1 disease (77% vs 37% and 61%), and congenital heart disease (CHD)-PAH (10.6% vs 0.0% and 4.8%, p < 0.001). Aneurysmal PA subjects had higher mPAP (46 [36-57] vs 19 [16- 25] and 35 [28-47] mmHg, p < 0.001), pulmonary vascular resistance (PVR) (5.5 [3.6-9.4] vs 1.7 [1.0-2.3] and 4.1 [2.4-7.1] Woods units, p < 0.001), cardiac index (CI; 2.73 [2.34-3.29] vs 2.55 [2.13-2.98] and 2.52 [2.12-3.10] L/min/m2, p < 0.02) and likelihood of death or transplant (p < 0.001; Figure 1). Conclusion “Aneurysmal” PA was more common in younger, non-White subjects with longer WSPH group 1 disease duration, CHD, and higher pro-BNP levels. Aneurysmal PA was associated with elevated mPAP, PVR, and CI, and reduced likelihood of survival. These findings highlight the need to further elucidate the pathophysiology and prognostic implications of aneurysmal PA remodeling in PH. This abstract is funded by: NHLBI and the Pulmonary Hypertension Association

Abstract Background We recently reported a strong association between CT markers of pulmonary artery (PA) dilation and mean PA pressure (mPAP) in subjects with World Symposium on Pulmonary Hypertension (WSPH) group 1 and 2 pulmonary hypertension (PH). The relationship between PA size and mPAP in subjects with WSPH group 3 PH, in which parenchymal changes may influence PA dilation, remains uncertain. We sought to investigate this relationship in subjects with and without PH who have significant parenchymal pulmonary disease or hypoxia. Methods We measured PA diameter and PA:aorta (PA:A) ratio on CT for all subjects with WSPH group 3 PH, matched disease comparators, and healthy controls in the Pulmonary Vascular Disease Phenomics (PVDOMICS) cohort. PH and comparator subjects were categorized by group 3 etiology into obstructive (including chronic obstructive pulmonary disease [COPD] and cystic fibrosis), interstitial (including idiopathic pulmonary fibrosis, unspecified interstitial lung disease, combined pulmonary fibrosis and emphysema, and chronic hypersensitivity pneumonitis), and non-parenchymal (including obesity hypoventilation syndrome, obstructive sleep apnea, and extrinsic restrictive disease) subgroups. Primary outcome was mPAP on right heart catheterization (RHC). Association with mPAP was evaluated using multivariable linear regression adjusted for age, sex, and BMI. Results 339 subjects met inclusion criteria (101 WSPH group 3 PH, 153 disease comparators, 85 healthy controls). 83 subjects had obstructive disease, 125 had interstitial disease, and 46 had non-parenchymal disease. PA diameter and PA:A were associated with mPAP in all subjects and in each subgroup (p < 0.001; see figure 1). The association was notably stronger in the non-parenchymal group (ρ = 0.707 for diameter, 0.750 for PA:A) compared to obstructive (ρ = 0.566 for diameter, 0.529 for PA:A) and interstitial (ρ = 0.432 for diameter, 0.373 for PA:A) groups. Change in PA size between 25th and 75th percentile mPAP was lower in the interstitial group (3.88 mm, ratio 0.12) than in the obstructive (4.88 mm, ratio 0.17) and non-parenchymal (4.80 mm, ratio 0.19) groups (see figure 1). Conclusions PA size on CT is associated with mPAP in subjects with chronic lung disease with and without PH. This association is strongest in subjects without parenchymal lung disease but with features of hypercarbia or hypoxia alone. These data suggest that features of parenchymal lung disease in certain patients may limit expected PA dilation in response to elevated PA pressures. Further study is needed regarding the implications of these findings for early identification of PH in patients with chronic lung disease. This abstract is funded by: The NHLBI and Pulmonary Hypertension Association

Abstract Rationale Pulmonary hypertension (PH) is a heterogeneous condition classified into 5 WSPH groups but lacking detailed molecular distinction. The PVDOMICS cohort includes all PH groups alongside healthy and disease comparators, is deeply clinically phenotyped and has RNA sequencing data. Pseudogenes are conserved genome elements that due to sequence-defects cannot be translated into functional proteins. Some pseudogenes never-the-less produce RNA-transcripts which can regulate the expression of other, protein coding genes. Therefore, our study was focused on identifying differentially expressed pseudogene-transcripts within the dataset from the PVDOMICS study and gaining insights into their potential function. Methods Peripheral venous whole blood was collected from PVDOMICS participants [n = 525 PH patients; n = 312 controls without PH who were comparators (n = 256) or healthy (n = 56)]. RNA was isolated, RNA sequencing was performed. After quality control, differential transcript expression between PH and control groups was analyzed using the limma-voom pipeline, rSEA with adjustment for age, sex, race, smoking, WSPH group, latent factors and false discovery rate. We focused on a) transcripts expressed at increased levels (n = 218): the first 200 DEG (differentially-expressed-genes)-transcripts based on log2 difference plus increased DEG within the first 200 most significant p-values; and b) transcripts expressed at decreased levels (n = 292): last 200 DEG based on log2 difference plus decreased DEG within the first 200 most significant p-values. Results Six pseudogene transcripts were among the increased and 35 pseudogene transcripts were among the decreased DEG in the PH group compared to controls. Some of the differentially expressed pseudogenes (DEP) belonged to gene families, like the ribosomal protein family (7 DEP), mitochondria expressed transcripts (3 DEP), zinc finger proteins (2 DEP). Associations of pseudogenes with biological function or disease were extracted via GeneCards(R) and information from GWAS analysis. The DUSP8P5 pseudogene was among the DEP and is known for its association with left heart disease and hypertension; 2 additional DEP have known association with hypertension. Further known associations were with inhibitory or inflammatory immune processes (8 DEP), bone density (6 DEP), metabolism and diabetes (6 DEP), respiratory function or disease (4 DEP), erythrocyte biology (3 DEP), cancer (5 DEP), kidney disease (1 DEP), and demographic parameters like eye or hair color (2 DEP). Ten DEP had no known association with function or disease. Conclusions We identified pseudogene RNA-transcripts associated with PH across WSPH groups. The local vs. systemic effects of these pseudogene transcripts on PH remain to be determined and regulators of pseudogene-transcript expression (e.g. environmental exposures) identified. This abstract is funded by: 1 X01 HL148611 (TopMed), PVDOMICS NHLBI, PVDOMICS Pulmonary Hypertension Association, HT9425-25-1-0533 (GG), 1R21OH012955-01 (GG)

BACKGROUND: The metabolic mechanisms underlying right ventricular (RV) dysfunction are poorly understood, particularly outside of group 1 pulmonary hypertension (PH). We aimed to identify metabolites and pathways associated with RV systolic function and explored whether associations differed by pulmonary vascular resistance, PH group 1 status, and sex. METHODS: We analyzed data from the multicenter PVDOMICS (Pulmonary Vascular Disease Phenomics) cohort. RV systolic function metrics included fractional area change (echo), global longitudinal strain (echo), and ejection fraction (cardiac magnetic resonance). We used linear regression adjusted for age, sex, body mass index, and PH group to assess associations between metabolites and RV function. Pathway enrichment analyses were used to identify pathways significantly associated with RV function. Interaction terms were assessed to determine whether metabolite associations were modified by pulmonary vascular resistance, group 1 PH status, or sex. Least absolute shrinkage and selection operator regression was used to develop metabolite-based scores for RV function, and prognostic performance was assessed. RESULTS: There were 979 participants with plasma metabolomics and RV function data. Linear regression identified 170 metabolites that were significantly associated with all 3 RV metrics. Androgenic steroid, gamma-glutamyl amino acid, polyamine, vitamin A, fatty acid, and sterol pathways are most strongly associated with RV systolic function. Two metabolites interacted with group 1 PH status, and 6 interacted with pulmonary vascular resistance. Four androgenic steroids are associated more strongly with RV systolic function in women compared with men. Metabolite-based scores were prognostically equivalent to RV systolic function metrics and less accurate than REVEAL Lite 2 scores. CONCLUSIONS: We provide a blueprint of metabolites and metabolic pathways associated with RV systolic function across the spectrum of PH. Novel links to vitamin A and glutathione metabolites were observed. We detected few metabolites that associated with RV systolic function differentially by group 1 PH status or degree of pulmonary vascular resistance elevation. Androgenic steroids may associate more strongly with RV systolic function in women compared with men.

BACKGROUND: With pulmonary hypertension (PH), a pulmonary artery wedge pressure (PAWP)>15 mm Hg is used to diagnose left heart dysfunction, but some patients with adjudicated group 1 PH demonstrate PAWP>15 mm Hg. The primary objective of the study was to evaluate group 1 PH with high PAWP>15 mm Hg. METHODS: Patients with adjudicated group 1 PH from PVDOMICS between 2016 and 2019 were separated into high PAWP(>15 mm Hg) or normal PAWP and compared with adjudicated combined pre- and postcapillary (Cpc) PH related to heart failure with preserved ejection fraction (HFpEF). Participants underwent dynamic right heart catheterization and metabolomics. Findings were validated in 3 independent cohorts with adjudicated group 1 PH (validation cohorts 1 and 2 with exercise right heart catheterization and validation cohort 3 with resting right heart catheterization). RESULTS: Of 325 patients with group 1 PH (73% women, mean age 53.0±14.3 years), 15% (n=48) had high PAWP. Group 1 PH+high PAWP demonstrated greater obesity, left ventricular hypertrophy ( P <0.0002), left ventricular strain impairment ( P <0.0001), and decreased left ventricular compliance ( P <0.0001) compared with group 1 PH+normal PAWP, with changes comparable to Cpc-PH HFpEF (n=75). Compared with Cpc-PH HFpEF, left atrial function was better in group 1 PH+high PAWP with lower PAWP V wave, higher left atrial compliance, and left atrial ejection fraction ( P <0.0001 for all). Metabolomics demonstrated little difference between group 1 PH with high versus normal PAWP but large differences between group 1 PH+high PAWP versus Cpc-PH HFpEF (100 metabolites altered at false discovery rate P <0.05). Elevated PAWP was also observed in 18% of group 1 PH in the validation cohort 1 (n=402), with exercise PAWP response intermediately abnormal in group 1 PH+high PAWP relative to Cpc-PH HFpEF and group 1 PH+normal PAWP (interaction P <0.0001). Elevated PAWP was similarly observed in 22% and 19% of group 1 PH in validation cohorts 2 (n=55) and 3 (n=787), respectively. CONCLUSIONS: Approximately 1 in 5 adjudicated patients with group 1 PH has elevation in resting PAWP despite severe pulmonary vascular dysfunction and metabolomics consistent with traditionally defined group 1 PH. Despite resting PAWP elevation, these patients with group 1 PH were metabolomically and biologically distinct from Cpc PH HFpEF, with better left atrial function and diastolic reserve during exercise. These data emphasize the limitations of using resting PAWP alone to separate group 1 PH from HFpEF and call for development of more integrated clinical diagnostic criteria.

BACKGROUND: Although obesity and insulin resistance (IR) are established risk factors for left heart dysfunction, their clinical impact in group 1 pulmonary hypertension (PH) remains unclear. We sought to determine the impact of excess adiposity versus IR on biventricular hemodynamic and functional reserve in group 1 PH. METHODS: Homeostasis model of insulin resistance and adiposity indices (body mass index [BMI], fat mass, waist circumference) were measured among group 1 patients with PH recruited to PVDOMICS (Redefining Pulmonary Hypertension Through Pulmonary Vascular Disease Phenomics). Functional capacity, and dynamic pulmonary capillary wedge pressure (PCWP) and right atrial pressure responses were compared stratified by obesity (BMI≥30 kg/m 2 ) and IR status (HOMA-IR≥2.6) using repeated-measure mixed models. RESULTS: Among patients with group 1 PH (n=418), 158 (38%) had BMI≥30 kg/m 2 (94 [60%] of whom had IR), and 260 (62%) had BMI<30 kg/m 2 (74 [28%] of whom had IR). Among those with waist circumference measurement (n=375), 287 (77%) had excess adiposity by elevated waist/height ratio, with 214 (57%) having elevated waist circumference. Patients with obesity had worse quality of life, exercise capacity and left heart remodeling, along with higher resting/dynamic PCWP, right atrial pressure and cardiac output ( P <0.0001 for all). Higher PCWP response with obesity persisted after adjusting for IR (IR-adjusted PCWP+2.5 mm Hg [95% CI, +1.4 to +3.6]; P <0.0001). All adiposity indices were consistently associated with PCWP response, but IR was not. Similar associations were observed between adiposity indices with higher right atrial pressure and cardiac output. Greater visceral adiposity as measured by body shape index (hazard ratio, 2.01 [95% CI, 1.16–3.47]; P =0.01) or weight-adjusted waist index (hazard ratio, 1.64 [95% CI, 1.10–2.46]; P =0.01) was associated with worse survival. CONCLUSIONS: Excess adiposity is common in group 1 PH, occurring in 4 out of 5 patients by the more sensitive waist/height ratio, in contrast to only 2 out of 5 patients having obesity by traditional BMI criteria. Excess adiposity is associated with higher biventricular filling pressures, cardiac output demand, worse functional status and reduced survival. These data support trials of adipose-reducing therapies in patients with group 1 PH and excess adiposity.