Beck, Gerald J

Background The current classification of pulmonary hypertension (PH), based largely on expert opinion, has limitations in prognostication and guiding therapies. We hypothesize that novel PH clusters that predict survival will reveal mechanistic phenotypes associated with biomarkers of vascular health across all PH groups. Methods We first identify novel PH clinical clusters by performing unsupervised clustering analysis on the CC‐PH (Cleveland Clinic PH) registry (N=1529). We develop classification models to predict the new PH clusters and then apply them to the multicenter PVDOMICS (Pulmonary Vascular Diseases Phenomics) cohort (N=853) for validation. We compare transplantation‐free survival across the new PH clusters. We quantify metabolites of the arginine‐nitric oxide pathway and D‐dimer levels and calculate global arginine bioavailability (arginine/[ornithine+citrulline]) to assess endothelial function and activation in the new clusters and link these biomarkers to clinical outcomes. Results Clustering analysis identify 3 clear clusters in CC ‐ PH that are validated in PVDOMICS and outperform conventional classifications in predicting transplantation‐free survival. The phenotype associated with the worst survival is characterized by reduced lung diffusion capacity, decreased arginine bioavailability and nitrate levels, and elevated D‐dimer levels, consistent with loss of pulmonary microcirculation and endothelial dysfunction. Conclusions We identify new informative PH phenotypes associated with mortality and defined by biomarkers of endothelial function and activation. Loss of endothelial health and pronounced pulmonary vascular rarefication contribute more substantially to mortality across the spectrum of PH than right heart function. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02980887.

ABSTRACT Background Pulmonary arterial hypertension (PAH) is characterized by circulating metabolic alterations, but whether these reflect disease-specific metabolic programs or reorganization of normal metabolic architecture, and how they relate to right ventricular-pulmonary vascular function (RV-PV), remains unclear. We hypothesized that the PAH metabolome is organized into biologically coherent, co-regulated metabolic modules whose relationships to RV-PV function would provide insight into known and novel metabolic pathways. Methods We applied weighted gene co-expression network analysis (WGCNA) to untargeted metabolomic data from 412 PAH patients enrolled in the multicenter PVDOMICS study. Module preservation analysis was performed in 85 healthy controls, with external replication in an independent single-center pulmonary hypertension cohort of 89 patients. Results WGCNA identified 16 distinct metabolic modules organized around biologically coherent programs. A coherent fatty acid axis, spanning substrate pools, β-oxidation intermediates, and conjugated fatty acid disposal products, formed a central organizing structure, with downstream fatty acid oxidation modules strongly associated with adverse hemodynamics and worse RV-pulmonary artery (PA) coupling. Acylcholine-enriched and 5α-reduced androgen metabolite modules were associated with favorable hemodynamic indices. Module architecture was largely preserved in healthy controls, with subtle disease-associated modular reorganization, rather than emergence of novel modules, observed in PAH. Core modules were recovered in the replication cohort with conserved hub metabolites. Conclusions These findings establish a systems-level framework demonstrating that PAH involves structured intensification and reorganization of interconnected metabolic programs associated with favorable and adverse RV-PV phenotypes. This work provides new insight into the metabolic architecture underlying PAH and identifies coordinated metabolic pathways linked to pulmonary vascular and right ventricular function.

Abstract Background World Symposium on Pulmonary Hypertension (WSPH) Group 2 pulmonary hypertension (PH) is a clinically integrated phenotype attributed to left heart disease, whereas pre- versus post-capillary classification is operationalized primarily by pulmonary capillary wedge pressure (PCWP). Although current recommendations emphasize contextual interpretation and provocative testing for intermediate PCWP values, the relationship between PCWP-based classification and underlying phenotype has not been systematically evaluated. We aim to quantify phenotype–hemodynamic discordance across the PCWP spectrum and evaluate a staged physiology-guided framework incorporating inhaled nitric oxide (iNO), ventricular geometry, and provocative testing. Methods We studied 1,032 participants from the NHLBI-sponsored PVDOMICS cohort with multidisciplinary adjudicated phenotypes integrating clinical, imaging, physiologic, and hemodynamic data. Stage-specific PCWP thresholds classified pre- versus post-capillary physiology at rest, during iNO, and during provocation (fluid challenge or invasive cardiopulmonary exercise testing [iCPET]). Echocardiographic right ventricular-to-left ventricular (RV/LV) ratio was evaluated as a marker of ventricular interdependence. Restricted cubic spline and staged concordance analyses defined certainty-based PCWP ranges and incremental diagnostic yield. Results Adjudicated Group 2 PH was present in 37.0% of participants. Resting PCWP demonstrated good discrimination (AUC 0.86), but substantial bidirectional phenotype–hemodynamic discordance persisted across intermediate PCWP ranges. At a resting PCWP of 12 mmHg, 25% of participants classified as pre-capillary had adjudicated Group 2 PH, whereas at 18 mmHg, 35% classified as post-capillary remained discordant non–Group 2. Concordance did not approach 90% until PCWP values were <9 mmHg or >24 mmHg. Dynamic testing incrementally improved concordance within these overlap zones. Nearly half of adjudicated Group 2 PH participants (46.5%) were not identified by resting PCWP alone; incorporation of iNO and provocative testing increased cumulative Group 2 identification by 63.4% and improved sensitivity from 79.9% to 83.7%. Model discrimination improved from an AUC of 0.863 to 0.908 (likelihood-ratio P<0.001). iNO increased PCWP in discordant Pre/G2 participants, unmasking latent left-sided limitation, while lowering PCWP in discordant Post/NonG2 participants, consistent with ventricular interdependence. RV/LV ratio ≥0.94 reduced discordant Post/NonG2 classification by 70.5%, and incorporation of PCWP/cardiac output slope improved physiologic specificity during exercise. Conclusions Group 2 PH is a dynamic, load-dependent phenotype inadequately characterized by resting PCWP alone. Intermediate PCWP values represent continuous probabilities of bidirectional discordance rather than discrete diagnostic states. A staged physiology-guided approach integrating iNO, ventricular geometry, and provocative testing improves concordance between hemodynamic classification and clinically integrated phenotype assignment. Clinical Perspective What Is New? In the deeply phenotyped PVDOMICS cohort, resting pulmonary capillary wedge pressure demonstrated good overall discrimination for adjudicated Group 2 (left heart disease) pulmonary hypertension, yet intermediate values frequently either concealed latent left-heart disease or overclassified patients without intrinsic left-heart disease Resting pulmonary capillary wedge pressure should be viewed as a continuous probability signal rather than a binary threshold, allowing additional physiologic testing to be targeted according to the degree of diagnostic uncertainty a clinician is willing to accept. A staged physiology-guided approach incorporating inhaled nitric oxide, ventricular geometry, and provocative testing improved concordance with adjudicated PH category and pre or post-capillary classification. What Are the Clinical Implications? Pre- versus post-capillary classification should be interpreted within the broader clinical and physiologic context rather than relying on a single resting pulmonary capillary wedge pressure threshold. Intermediate pulmonary capillary wedge pressure values should prompt consideration of additional physiologic evaluation, with inhaled nitric oxide providing a practical intermediate step and provocative testing providing the greatest incremental diagnostic yield. Exercise pulmonary capillary wedge pressure/cardiac output slope and markers of ventricular interdependence may provide complementary information for resolving uncertainty when resting and dynamic hemodynamics are discordant.

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: 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.

Background Right ventricular (RV) maladaptation to elevated pulmonary afterload is the primary determinant of outcomes in pulmonary artery (PA) hypertension; however, the pathobiological mechanisms underlying RV decompensation remain poorly understood. Methods We performed global untargeted metabolomics on plasma from 55 patients who underwent gold‐standard RV‐PA coupling measurements using multibeat pressure volume loop assessment in a single‐center cohort and from 1027 patients with coupling surrogate measurements in a larger multicenter cohort, the PVDOMICS (Pulmonary Vascular Disease Phenomics) study. Age and sex‐adjusted linear regression was performed to identify associations between metabolites and coupling metrics. Additionally, we performed a metabolic flux analysis using gene expression data from RV tissue in an independent cohort of 32 patients. Partial least squares–discriminant analysis was used to identify metabolites and reactions characteristic of the decompensated RV. Results RV‐PA coupling was negatively associated with tricarboxylic acid (TCA) cycle intermediate levels. Specifically, plasma α‐ketoglutarate and fumarate were significantly associated with all coupling metrics in both cohorts. Metabolic flux analysis indicated that decompensated RVs exhibited aberrant TCA cycle activity, including reduced acetyl coenzyme A entry and increased lactate elimination, suggesting a shift from the TCA cycle toward glycolysis at the RV tissue level. Conclusions We identify an association between circulating TCA cycle intermediate levels and RV‐PA uncoupling in 2 independent cohorts, and dysregulated TCA cycle metabolism in decompensated PA hypertension RVs, suggesting that aberrant TCA cycle metabolism could represent a hallmark of RV maladaptation in PA hypertension. Further study of this pathway is warranted to develop novel biomarkers of RV function or RV‐targeted therapies.