Park, Margaret

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.

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.

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.

Introduction: Assessment of right ventricular (RV) size and function by echo is challenging due to complex RV anatomy and requires integration of multiple measurements. We sought to compare accuracy of echo measures of RV size and function with cardiac MRI (CMR) in pulmonary hypertension (PH). Methods: We included patients with PH from the PVDOMICS Study who underwent both echo and CMR. Echo measures of RV size (basal dimension, area, 3D volume) and function (fractional area change [FAC], 3D RV ejection fraction [EF], RV global longitudinal strain [GLS], S’, TAPSE, Tei index) were compared to CMR derived RV volumes and RVEF. Agreement was assessed using Bland-Altman (BA) plots and Lin’s concordance correlation coefficients (ρ c ). Predictive trends were evaluated using linear regression. Results: The cohort included 446 subjects (58 ± 15 yrs, 36% male). Echo measures of RV size showed poor agreement with CMR, but substantial linear associations, when comparing CMR end diastolic volume (EDV) with: echo basal dimension (ρ c = 0.002; β = 60, R 2 = 0.47), end-diastolic area (ρ c = 0.04, β = 6.4, R 2 = 0.64), and 3D EDV (bias = 106, limits of agreement [LOA]: -14.1 to 225); and also when comparing CMR end-systolic volume (ESV) with: end-systolic area (ρ c = 0.08; β = 6.8, R 2 = 0.74) and 3D ESV (bias = 67.3, LOA: -31.8 to 166). Select echo measures of RV function demonstrated better agreement with CMR RVEF including: 3D RVEF (bias -0.23, LOA -17.9 to 17.5) and FAC (ρ c = 0.55; β = 0.89, R 2 = 0.50). Others exhibited modest or poor agreement including: RV GLS (ρ c = 0.11; β = -1.5, R 2 = 0.40), along with S’, TAPSE, and Tei index (ρ c ≤ 0.02; R 2 ≤ 0.19 for all). [Figure] Discussion: In this largest comparison of echo vs CMR measures of RV assessment in PH, echo measures of RV size agreed poorly with CMR, especially at larger RV volumes. RV functional assessment was best with echo 3D RVEF and FAC, which should be preferentially used for echo RV functional assessment. Consider CMR for more accurate volume assessment of RV size.

Background: Normative changes in right ventricular (RV) structure and function have not been characterized in the context of treatment-associated functional recovery (RV functional recovery [RVFnRec]). The aim of this study is to assess the clinical relevance of a proposed RVFnRec definition. Methods: We evaluated 63 incident patients with pulmonary arterial hypertension by right heart catheterization and cardiac magnetic resonance imaging at diagnosis and cardiac magnetic resonance imaging and invasive cardiopulmonary exercise testing following treatment (≈11 months). Sex, age, ethnicity matched healthy control subjects (n=62) with 1-time cardiac magnetic resonance imaging and noninvasive cardiopulmonary exercise testing were recruited from the PVDOMICS (Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics) project. We examined therapeutic cardiac magnetic resonance imaging changes relative to the evidence-based peak oxygen consumption (VO 2peak )>15 mL/(kg·min) to define RVFnRec by receiver operating curve analysis. Afterload was measured as mean pulmonary artery pressure, resistance, compliance, and elastance. Results: A drop in RV end-diastolic volume of −15 mL best defined RVFnRec (area under the curve, 0.87; P =0.0001) and neared upper 95% CI RV end-diastolic volume of controls. This cutoff was met by 22 out of 63 (35%) patients which was reinforced by freedom from clinical worsening, RVFnRec 1 out of 21 (5%) versus no RVFnRec 17 out of 42, 40% (log-rank P =0.006). A therapy-associated increase of 0.8 mL/mm Hg in compliance had the best predictive value of RVFnRec (area under the curve, 0.76; [95% CI, 0.64–0.88]; P =0.001). RVFnRec patients had greater increases in stroke volume, and cardiac output at exercise. Conclusions: RVFnRec defined by RV end-diastolic volume therapeutic decrease of −15 mL predicts exercise capacity, freedom from clinical worsening, and nears normalization. A therapeutic improvement of compliance is superior to other measures of afterload in predicting RVFnRec. RVFnRec is also associated with increased RV output reserve at exercise.

Abstract Aims Iron deficiency is common in pulmonary hypertension, but its clinical significance and optimal definition remain unclear. Methods and results Phenotypic data for 1028 patients enrolled in the Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics study were analyzed. Iron deficiency was defined using the conventional heart failure definition and also based upon optimal cut-points associated with impaired peak oxygen consumption (peakVO2), 6-min walk test distance, and 36-Item Short Form Survey (SF-36) scores. The relationships between iron deficiency and cardiac and pulmonary vascular function and structure and outcomes were assessed. The heart failure definition of iron deficiency endorsed by pulmonary hypertension guidelines did not identify patients with reduced peakVO2, 6-min walk test, and SF-36 (P &gt; 0.208 for all), but defining iron deficiency as transferrin saturation (TSAT) &lt;21% did. Compared to those with TSAT ≥21%, patients with TSAT &lt;21% demonstrated lower peakVO2 [absolute difference: −1.89 (−2.73 to −1.04) mL/kg/min], 6-min walk test distance [absolute difference: −34 (−51 to −17) m], and SF-36 physical component score [absolute difference: −2.5 (−1.3 to −3.8)] after adjusting for age, sex, and hemoglobin (all P &lt; 0.001). Patients with a TSAT &lt;21% had more right ventricular remodeling on cardiac magnetic resonance but similar pulmonary vascular resistance on catheterization. Transferrin saturation &lt;21% was also associated with increased mortality risk (hazard ratio 1.63, 95% confidence interval 1.13–2.34; P = 0.009) after adjusting for sex, age, hemoglobin, and N-terminal pro-B-type natriuretic peptide. Conclusion The definition of iron deficiency in the 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) pulmonary hypertension guidelines does not identify patients with lower exercise capacity or functional status, while a definition of TSAT &lt;21% identifies patients with lower exercise capacity, worse functional status, right heart remodeling, and adverse clinical outcomes.

AbstractChronic thromboembolic pulmonary hypertension (CTEPH) is believed to involve both vascular obstruction and vasoconstriction; hence, pulmonary vasodilators such as riociguat may be beneficial. Acute vasoreactivity testing (AVT) is seldom performed routinely in CTEPH patients, so there is limited understanding of the frequency and significance of an acute vasodilator response. Systematic vasodilator testing with oxygen (O2) and oxygen plus inhaled nitric oxide (O2 + iNO) was performed as part of the Pulmonary Vascular Disease Omics (PVDOMICS) NHLBI project, providing an opportunity to examine AVT responses in CTEPH. Patients with CTEPH enrolled in PVDOMICS (n = 49, 40 with prevalent CTEPH [82%]) underwent right heart catheterization including AVT with O2 and O2 + iNO. Hemodynamics were obtained at baseline and with each challenge. Fourteen of 49 patients (29%) had >20% drop in pulmonary vascular resistance (PVR) with O2. With O2 + iNO, 30/49 (61%) had >20% drop in PVR, 20% had >20% drop in mean pulmonary artery pressure (mPAP) and PVR, and 8% had >10 mmHg decline in mPAP to mPAP < 40 with normal cardiac output. Patients on riociguat had less response to O2 + iNO than patients on phosphodiesterase‐5 inhibitors. Our findings shed light on the significant variability in vascular tone that is present in CTEPH, confirming that CTEPH represents a combination of mechanical obstruction and vasoconstriction that appears similar to that observed with Group 1 PAH. Additional study regarding whether results of acute vasodilator testing predict response to therapy and relate to prognosis is warranted.

Abstract Aims There is a wide spectrum of diseases associated with pulmonary hypertension, pulmonary vascular remodelling, and right ventricular dysfunction. The NIH-sponsored PVDOMICS network seeks to perform comprehensive clinical phenotyping and endophenotyping across these disorders to further evaluate and define pulmonary vascular disease. Methods and results Echocardiography represents the primary non-invasive method to phenotype cardiac anatomy, function, and haemodynamics in these complex patients. However, comprehensive right heart evaluation requires the use of multiple echocardiographic parameters and optimized techniques to ensure optimal image acquisition. The PVDOMICS echo protocol outlines the best practice approach to echo phenotypic assessment of the right heart/pulmonary artery unit. Conclusion Novel workflow processes, methods for quality control, data for feasibility of measurements, and reproducibility of right heart parameters derived from this study provide a benchmark frame of reference. Lessons learned from this protocol will serve as a best practice guide for echocardiographic image acquisition and analysis across the spectrum of right heart/pulmonary vascular disease.