Mathai, Stephen C

Abstract Rationale A subset of patients with group 1 pulmonary hypertension (PH) have superimposed left heart abnormalities with unclear metabolic implications. Objectives To compare serum/transpulmonary metabolome between group 1 PH stratified by heart failure with preserved ejection fraction (HFpEF) probability. Methods Patients with group 1 PH were stratified into low (<25%) and high (⩾75%) HFpEF-ABA (age, body mass index, and atrial fibrillation) probability, with healthy control subjects and subjects with clinical HFpEF used for comparison of venous and transpulmonary metabolomics. Measurements and Main Results Group 1 PH + high HFpEF probability (n = 131) was associated with a significant increase in 207 metabolites (false discovery rate [FDR] P < 0.05 and fold change >1) (n = 193, t test) and a significant decrease in 231 metabolites (FDR P < 0.05 and fold change <1) (n = 193, t test) compared with group 1 PH + low HFpEF probability (n = 62). Group 1 PH + high HFpEF probability was associated with enhanced tryptophan metabolism with higher downstream kynurenine metabolite concentrations and lower serotonin concentrations (FDR P < 0.002 for all, n = 193, t test). Linoleate (precursor to arachidonic acid and prostaglandins) and arginine and homoarginine (precursors to nitric oxide) were all lower in group 1 PH + high HFpEF probability (FDR P < 0.03 for all, n = 193, t test). Metabolome changes in group 1 PH + high HFpEF probability overlapped with clinical HFpEF (n = 240) but were abnormal relative to control subjects (n = 85) (P < 0.0001 for all, n = 456, t test). There was no evidence of differential transpulmonary uptake/release of most metabolites, suggesting probable nonpulmonary origin (except for serotonin, interaction P = 0.04; and kynurenine, interaction P = 0.03; n = 433, mixed model). Conclusions Patients with group 1 PH + high HFpEF probability have a unique metabolome characterized by enhanced tryptophan-kynurenine pathway breakdown, deficiency of amino acids (such as glycine and serine), lower serotonin, and decreased prostaglandin and nitric oxide precursors. Despite fulfilling clinical criteria for group 1 PH, these metabolome changes were comparable with clinical HFpEF, supporting biological overlap between these two forms of PH.

BACKGROUND: Patients with lung disease, sleep apnea, and chronic thromboemboli can develop pulmonary hypertension, currently classified as group 3 or 4. Many of these patients also have risk factors for heart failure with preserved ejection fraction (HFpEF), but the optimal approach to identify the disease overlap remains unclear. METHODS: Pretest probability for HFpEF was determined using the HFpEF-ABA (age, body mass index, atrial fibrillation) algorithm among adjudicated group 3 or 4 patients at risk for pulmonary hypertension in the PVDOMICS study (Redefining Pulmonary Hypertension Through Pulmonary Vascular Disease Phenomics). Patients were stratified by current resting right heart catheterization criteria, and in a separate analysis, stratified only by HFpEF-ABA probability into low (<25%), intermediate, and high (≥75%) HFpEF probability groups. RESULTS: Among 598 patients with group 3 disease, 27% (n=161) had elevated pulmonary capillary wedge pressure (PCWP) with postcapillary pulmonary hypertension even at rest, which was associated with the highest exercise PCWP. However, regardless of this resting PCWP-based classification, a larger subset had intermediate-to-high HFpEF-ABA probabilities (32% [n=197] high and 57% [n=358] intermediate HFpEF probability). High HFpEF probability in group 3 disease was associated with higher resting and dynamic PCWP response to NO, fluid, and exercise ( P <0.0001 for all). These changes were comparable with more traditionally defined HFpEF without pulmonary vascular disease (n=61) but less severe than those with combined precapillary and postcapillary pulmonary hypertension HFpEF (n=31; interaction P =0.006). Increasing HFpEF probability in group 3 disease was associated with worse left heart remodeling, quality of life, 6-minute walk distance, and peak VO 2 ( P <0.0001 for all). Findings were replicated in group 4 disease (n=102). CONCLUSIONS: Quantifying pretest probability for HFpEF in patients with sleep apnea, lung disease, or chronic thromboemboli identifies a progressive gradient for dynamic PCWP abnormalities with worse functional status and quality of life. These subclinical left heart abnormalities are not universally detectable by resting right heart catheterization alone and call for further study of whether strategies to prevent or treat HFpEF might improve functional status in these patients with high risk of occult HFpEF.

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.

Abstract Rationale: The 7th World Symposium on Pulmonary Hypertension highlighted the importance of patient-reported outcomes in clinical assessment of pulmonary arterial hypertension (PAH). Patient-reported outcomes, such as health-related quality of life (HRQOL), have been associated with morbidity and mortality in PAH, but the added value of HRQOL measures to validated risk prediction models remains unknown. Methods: Adults with RHC-proven PAH from the Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics (PVDOMICS) Study, a multi-center observational study, were included in this study. The Pulmonary Hypertension Association Registry (PHAR) was used as a validation cohort. HRQOL was measured using the emPHasis-10 score, where higher scores reflect worse HRQOL. Noninvasive risk assessment was measured by REVEAL Lite 2 risk score, categorized into 3-strata. Cox proportional hazard models were used to model survival evaluating the interaction between risk strata and HRQOL scores, adjusting for age, sex, and incident diagnosis. Harrell's C-statistics were calculated to compare discriminative performance. Results: From the PVDOMICS and PHAR cohorts, 265 and 2671 individuals with PAH and complete emPHasis-10 and REVEAL Lite 2 scores were included. Both cohorts had similar demographics, with an average age of 52±13 and 56±16 years, 75% and 72% female, 81% and 75% White, in the PVDOMICS and PHAR cohorts respectively. Over 87% of PVDOMICS were prevalent cases of PAH, while in the PHAR half were incident. Most individuals (62%) in PVDOMICS were REVEAL Lite 2 low risk, with 16% intermediate and 22% high risk; by contrast, in PHAR 33% were low, 29% intermediate, and 38% high risk. REVEAL Lite 2 scores demonstrated weak to moderate correlation with emPHasis-10 scores in both cohorts (PVDOMICS r=0.48 p&lt;0.001; PHAR r=0.33 p&lt;0.001). Notably, the full range of emPHasis-10 scores were observed in the low-risk individuals across both cohorts. In the PVDOMICS adjusted Cox models, higher emPHasis-10 scores predicted poorer survival (p=0.047) particularly among low-risk individuals (interaction versus high-risk group p=0.08). Similar adjusted models in PHAR demonstrated emPHasis-10 to be a confounder (p=0.001) without significant interaction by risk strata (low vs high-risk interaction p=0.94), but the greatest change in median survival time was observed in the low-risk group (Figure 1). Addition of emPHasis-10 to REVEAL Lite 2 scores improved discrimination in predicting survival (PVDOMICS: C-statistic 0.71 vs 0.73; PHAR: C-statistic 0.67 vs 0.69). Conclusions: Across two multicenter cohorts of incident and prevalent PAH, HRQOL as measured by the emPHasis-10 score improved discrimination for survival, particularly among individuals with lower risk scores.

Abstract Rationale: Although guidelines recommend the use of provocative testing to diagnose pulmonary venous hypertension (PVH) that is unapparent at normal resting right heart catheterization (RHC), the incremental value of provocative testing is unknown. We aim to evaluate the incremental diagnostic capability of inhaled nitric oxide (iNO), fluid challenge (FC) or invasive cardiopulmonary exercise testing (iCPET) to unmask PVH using previously defined hemodynamic cutoffs. Methods: We included subjects from the NHLBI-funded Pulmonary Vascular Disease Phenomics (PVDOMICS) study. Our analysis included patients with World Symposium on Pulmonary Hypertension (WSPH) Group 2 disease (G2PH) and G2PH comparators (WSPH Group 2 phenotype without a diagnosis of PH) as determined by the PI or adjudication panel. We then applied a protocol-driven provocative approach based on the feasibility of modalities available in most catheterization labs. Using a pulmonary capillary wedge pressure (PCWP) cutoff of &gt;15, frequencies were identified for subjects based on resting PCWP and with iNO. Frequencies were also identified for: those who received FC with a PCWP cutoff of ≥18 or those who received iCPET with PCWP cutoff of &gt;20 (upright) or &gt;25 (supine). Results: There were 419 subjects identified with WSPH Group 2 disease (Figure). Roughly half were found to have a PCWP &gt;15 during resting RHC (N = 207). Of the remaining subjects with a resting PCWP ≤15 (N = 150), 42 subjects were found to have a PCWP &gt;15 with iNO administration (40.0%). Of the remaining 63 subjects with PCWP ≤15 following iNO administration, nearly half (N = 26, 48.0%) demonstrated a PCWP ≥18 following FC while 8 subjects (14.8%) demonstrated an elevated PCWP following iCPET. Conclusions: There is a high proportion of G2PH patients (∼35%) who appear hemodynamically similar to precapillary PH at rest. Inhaled nitric oxide vasodilatory challenge unmasks G2PH in many patients. In situations where iNO does not disclose the G2PH phenotype, provocation with FC or iCPET can be useful as a supplementary provocative maneuver. Future directions will focus on agnostically assessing the utility of provocation based on grouping subjects by resting hemodynamics as well as assessing the use of provocation in other forms of PH.

Abstract Rationale Pulmonary arterial hypertension (PAH) is associated with significant morbidity and mortality. The extent of medication nonadherence in PAH is uncertain and may be linked to adverse outcomes. There has been a lack of multicenter, registry-based studies assessing medication nonadherence and patient-centered outcomes in PAH. Objectives To determine the prevalence of self-reported nonadherence in Pulmonary Hypertension Association Registry (PHAR) participants with PAH or chronic thromboembolic pulmonary hypertension and the relationship of nonadherence with several patient-centered outcomes (mortality, hospitalization rates, emergency department visits, and health-related quality of life). Methods Self-reported PAH medication nonadherence was captured at PHAR enrollment and during follow-up visits. Predictors of nonadherence were modeled using generalized estimating equations assuming a binary distribution. Outcomes associated with nonadherence were modeled using generalized estimating equations with a Poisson distribution. Results A total of 1,543 patients were included, of whom 1,092 (70.8%) were female and 1,340 (86.8%) had PAH. The overall rate of any self-reported nonadherence was 6.1% (95% confidence interval [CI], 5.3–6.9). Predictors of nonadherence included self-reported male sex at birth (odds ratio [OR], 1.4; 95% CI, 1.0–1.9; P = 0.02), poverty (OR, 1.6; 95% CI, 1.2–2.3; P = 0.01), not being married or partnered (OR, 1.5; 95% CI, 1.1–1.9; P = 0.01), having Medicaid or no health insurance (OR, 2.1; 95% CI, 1.5–2.9; P &lt; 0.001), and having completed high school but not having a college degree (OR, 1.7; 95% CI, 1.1–2.9; P &lt; 0.001). PHAR participants who reported any nonadherence had 50.0% more emergency department visits (P &lt; 0.001), 13.3% more hospital admissions (P = 0.03), and 61.9% more days hospitalized (P = 0.01). No relationship was observed between nonadherence and the type or number of PAH therapies or all-cause mortality. Participants reporting nonadherence had worse mean Short Form-12 scores (P &lt; 0.001) and worse emPHasis-10 scores (P = 0.02). Conclusions The rate of self-reported nonadherence in PHAR registrants was low but was associated with male sex and several social determinants of health. Although the complexity or type of PAH regimen did not appear to influence nonadherence, nonadherence was associated with numerous adverse patient-centered outcomes, including greater healthcare use and worse health-related quality of life. Because of limitations in the structure of the gathered data, relationships between exposure and outcomes were not temporally definitive; these observations warrant additional prospective studies.

BACKGROUND: Defining qualitative grades of echocardiographic metrics of right heart chamber size and function is critical for screening, clinical assessment, and measurement of therapeutic response in individuals with pulmonary vascular disease (PVD). In a population enriched for PVD, we sought to establish qualitative grades and prognostic value of right heart chamber size and function. METHODS: We investigated 1053 study participants in PVDOMICS (Redefining Pulmonary Hypertension Through the PVD Phenomics Program) to determine clinical and echocardiographic differences associated with increasing pulmonary vascular resistance severity. Right heart chamber size and function were qualitatively assessed using a percentile-based approach above the median values to create a clinical grading system for right heart adaptation. The relationship between echocardiographic categories and all-cause mortality was examined using survival analyses adjusted for potential confounders. RESULTS: A stepwise increase in adverse right heart remodeling was observed with a concomitant decrease in functional parameters by pulmonary vascular resistance strata ( P <0.001 for all). Mild, moderate, and severe categories of right heart chamber size and dysfunction were defined using a percentile-based approach across the spectrum of PVD. During a median follow-up of 2.07 years (interquartile range, 1.23–3.01 years), 130 participants died (11.4%). Progressive pulmonary vascular resistance increase and 2DE evidence of right heart dysfunction inclusive of fractional area change, and right ventricular global longitudinal strain were independently associated with increased all-cause mortality risk in multivariate analysis adjusted for age, disease duration, and male sex. CONCLUSIONS: In this well-characterized sample of adults with diverse etiologies and varying PVD severity, we define categories of abnormal right heart chamber size and function. Further, we demonstrate a stepwise relationship between these categories of abnormal morphology and function and all-cause mortality. Defining grades of right ventricular dysfunction in individuals with known PVD has important clinical implications for monitoring disease progression and response to therapies.

Abstract Aims The clinical utility of pulmonary hypertension (PH) risk scores in non-group 1 PH with pulmonary vascular disease (PVD) remains unresolved. Methods and results We utilized the prospective multicenter PVDOMICS cohort with group 2, 3, 4 or 5 PH-related PVD and calculated group 1 PH risk scores (REVEAL 2.0, REVEAL Lite 2, French registry score and COMPERA 2). The c-statistic to predict death was compared separately in (i) pre-capillary PH groups 3/4/5, and (ii) combined post- and pre-capillary PH group 2. Exercise right heart catheterization reserve, ventricular interdependence and right ventricular–pulmonary artery (RV-PA) coupling were compared across risk categories. Among 449 individuals with group 3/4/5 PH, the REVEAL 2.0 risk score had the highest c-statistic for predicting death (0.699, 95% confidence interval [CI] 0.660–0.737, p &lt; 0.0001) with comparable performance using the simpler REVEAL Lite 2 score (0.695, 95% CI 0.656–0.734, p &lt; 0.0001). The French and COMPERA 2 risk scores were also predictive of mortality, but performance of both was statistically inferior to REVEAL 2.0 (c-statistic difference −0.072, 95% CI −0.123 to −0.020, p = 0.006, and −0.043, 95% CI −0.067 to −0.018, p = 0.0007, respectively). RV function and RV-PA coupling measures were prognostic in isolation, but did not add incremental value to REVEAL (p &gt; 0.50 for all). Findings were similar in patients with group 2 PH (n = 239). Stratification by the REVEAL Lite 2 score non-invasively identified non-group 1 PH with more advanced PVD with worse exercise capacity, RV-PA uncoupling, ventricular interdependence and impaired cardiac output reserve (p &lt; 0.05 for all). Conclusions Non-invasive REVEAL risk predicts mortality in non-group 1 PH without incremental prognostic value from detailed RV function or RV-PA coupling assessment. Baseline REVEAL Lite 2 risk stratification non-invasively identifies greater pulmonary vascular dysfunction and right heart-related exercise limitation, which may help guide patient selection for targeted pulmonary vascular therapies in non-group 1 PH.

Abstract Rationale Inhibition of aromatase with anastrozole reduces pulmonary hypertension in experimental models. Objectives We aimed to determine whether anastrozole improved the 6-minute-walk distance (6MWD) at 6 months in pulmonary arterial hypertension (PAH). Methods We performed a randomized, double-blind, placebo-controlled phase II clinical trial of anastrozole in subjects with PAH at seven centers. Eighty-four postmenopausal women with PAH and men with PAH were randomized in a 1:1 ratio to receive anastrozole 1 mg or placebo by mouth daily, stratified by sex using permuted blocks of variable sizes. All subjects and study staff were masked. The primary outcome was the change from baseline in 6MWD at 6 months. By intention-to-treat analysis, we estimated the treatment effect of anastrozole using linear regression models adjusted for sex and baseline 6MWD. Assuming 10% loss to follow-up, we anticipated having 80% power to detect a difference in the change in 6MWD of 22 meters. Measurements and Main Results Forty-one subjects were randomized to placebo and 43 to anastrozole, and all received the allocated treatment. Three subjects in the placebo group and two in the anastrozole group discontinued the study drug. There was no significant difference in the change in 6MWD at 6 months (placebo-corrected treatment effect, −7.9 m; 95% confidence interval, −32.7 to 16.9; P = 0.53). There was no difference in adverse events between the groups. Conclusions Anastrozole did not show a significant effect on 6MWD compared with placebo in postmenopausal women with PAH and in men with PAH. Anastrozole was safe and did not have adverse effects. Clinical trial registered with www.clincialtrials.gov (NCT03229499).

Purpose: New 2022 European Society of Cardiology/European Respiratory Society PAH guidelines recommend treatment guided by a multi-parameter risk assessment. 1 Patients with low/intermediate risk without cardiopulmonary comorbidities should start dual PAH combination therapy; those with cardiopulmonary comorbidities should be reassessed early for rapid escalation to dual therapy. Initial triple therapy is recommended for high-risk patients. We examined use of dual and triple PAH therapy in the US (before guideline update). Methods: We used the Pulmonary Hypertension Association Registry (PHAR), a prospective US registry of pulmonary hypertension (PH) patients, enrolled within 6 months of their first outpatient visit at one of 54 participating PH care centers in the US, between Sep 2015-Jun 2022. We included adults (≥18 years at enrollment) with incident PAH (newly diagnosed and treated within 6 months of enrollment) and ≥1 follow-up clinic visit post baseline visit. Chronic thromboembolic PH patients were excluded. Results: We analyzed (descriptive statistics) 794 incident patients (baseline characteristics in Table 1). Treatment patterns at baseline (n=794)/last follow-up visit (n=610) were 289 (36.4%)/102 (16.7%) on monotherapy, 419 (52.8%)/314 (51.5%) on dual combination, 83 (10.5%)/179 (29.3%) on triple combination therapy, respectively. Mean time from enrollment to dual and triple combination therapy was 86.1 (standard deviation [SD]: 209.0) and 346.1 days (SD: 430.8), respectively. Conclusions: Among incident PHAR patients, half received initial dual and 10% triple upfront combination therapy. At last follow-up, most (>80%) patients had escalated to dual/triple combination therapies. Clinical Implications: At PH care centers, most incident PHAR patients are escalated to dual and triple therapy (at last follow-up) per current guidelines. Reference 1. Humbert M, et al. Eur Heart J. 2022;43:3618-731.