Prognostic value of right ventricular mass, volume, and function in idiopathic pulmonary arterial hypertension

Association between right heart size and right ventricular output reserve in patients with pulmonary arterial hypertension

OBJECTIVES

Right ventricular (RV) output reserve, defined as increase of cardiac output during exercise, is reduced in patients with pulmonary arterial hypertension (PAH). Aim of this study was to evaluate the association of right heart size measured by echocardiography and invasively measured RV function at rest and during exercise in PAH patients.

METHODS

Adult PAH-patients who received routine haemodynamic assessment at rest and during exercise by right heart catheterisation and echocardiographic measurement of right heart size (right atrial (RA) and RV area) were included in this study. Clinical, echocardiographic, laboratory, exercise and invasive haemodynamic parameters were retrospectively analysed. The primary endpoint was to assess the association between right heart size and right ventricular function.

RESULTS

Data from 215 PAH patients (age 58.9 ± 15.9 years, 63.3% female, 62.2% double or triple combination treatment) were analysed in this cross-sectional study. Cardiac index was significantly lower for patients with enlarged RA-area > 18 cm2 at rest, and at 25 and 50 W (all p < 0.001) and for patients with enlarged RV area > 20 cm2 at rest, 25, 50 and 75 W (all p < 0.001). Furthermore, pulmonary vascular resistance and mPAP/CO slope (all p < 0.001) were significantly higher and pulmonary arterial compliance (all p < 0.05) was significantly lower in patients with enlarged RA or RV area. RA and RV area correlated with TAPSE/sPAP (both p < 0.001, R - 0.570 and - 0.530).

CONCLUSION

This study could underline that an enlargement of RA- and RV-area is associated with an impaired RV function at rest and during exercise in patients with PAH.

Native myocardial T1 and right ventricular size by CMR predict outcome in systemic sclerosis-associated pulmonary hypertension

OBJECTIVES

Measures of right heart size and function are prognostic in systemic sclerosis-associated pulmonary hypertension (SSc-PH), but the importance of myocardial tissue characterisation remains unclear. We aimed to investigate the predictive potential and interaction of cardiovascular magnetic resonance (CMR) myocardial tissue characterisation and right heart size and function in SSc-PH.

METHODS

A retrospective, single-centre, observational study of 148 SSc-PH patients confirmed by right heart catheterization who underwent clinically indicated CMR including native myocardial T1 and T2 mapping from 2016 to 2023 was performed.

RESULTS

Sixty-six (45%) patients died during follow-up (median 3.5 years, range 0.1-7.3). Patients who died were older (65 vs 60 years, P = 0.035) with more dilated (P < 0.001), hypertrophied (P = 0.013) and impaired (P < 0.001) right ventricles, more dilated right atria (P = 0.043) and higher native myocardial T1 (P < 0.001).After adjustment for age, indexed right ventricular end-systolic volume (RVESVi, P = 0.0023) and native T1 (P = 0.0024) were independent predictors of all-cause mortality. Both RVESVi and native T1 remained independently predictive after adjusting for age and PH subtype (RVESVi P < 0.001, T1 P = 0.0056). Optimal prognostic thresholds for RVESVi and native T1 were ≤38 mL/m2 and ≤1119 ms, respectively (P < 0.001). Patients with RVESVi ≤ 38 mL/m2 and native T1 ≤ 1119 ms had significantly better outcomes than all other combinations (P < 0.001). Furthermore, patients with RVESVi > 38mL/m2 and native T1 ≤ 1119 ms had significantly better survival than patients with RVESVi > 38mL/m2 and native T1 > 1119ms (P = 0.017).

CONCLUSION

We identified prognostically relevant CMR metrics and thresholds for patients with SSc-PH. Assessing myocardial tissue characterisation alongside right ventricular function confers added value in SSc-PH and may represent an additional treatment target.

Low Thyroid Hormones Level Attenuates Mitochondrial Dysfunction and Right Ventricular Failure in Pulmonary Hypertensive Rats

PURPOSE

This study is to investigate the repercussions of hypothyroidism in the pathophysiological progression of pulmonary arterial hypertension (PAH).

METHODS

While the control (CTL, n = 5) male Wistar rats received vehicle, PAH was induced with monocrotaline (MCT group, n = 15). Hypothyroidism was induced in a subset of rats by methimazole 3 weeks prior to the MCT injection (MMZ + MCT group, n = 15). Plasma thyroid hormones were measured by radioimmunoassay. Electrocardiographic, echocardiographic, and hemodynamic analyses were performed to evaluate the progression of PAH. Gene expression of antioxidant enzymes and cardiac hypertrophy markers were assessed by qPCR. Mitochondrial respiration, ATP levels, and ROS production were measured in right ventricular (RV) samples.

RESULTS

Plasma T3 and T4 decreased in both MCT and MMZ + MCT groups (p < 0.05). Right ventricular systolic pressure (RVSP) increased, and RV - dP/dt, + dP/dt, and contractility index decreased in the MCT versus the CTL group and remained within control levels in the MMZ + MCT group (p < 0.05). Relative RV weight, RV wall thickness, RV diastolic area, and relative lung weight were augmented in the MCT versus the CTL group, whereas all parameters were improved to the CTL levels in the MMZ + MCT group (p < 0.05). Only the MCT group exhibited an increased duration of QTc interval compared to the baseline period (p < 0.05). ADP-induced mitochondrial respiration and ATP levels were decreased, and ROS production was increased in MCT versus the CTL group (p < 0.05), while the MMZ + MCT group exhibited increased mitochondrial respiration versus the MCT group (p < 0.05).

CONCLUSION

Hypothyroidism attenuated the RV mitochondrial dysfunction and the pathophysiological progression of MCT-induced PAH.

Risk stratification and treatment goals in pulmonary arterial hypertension

Risk stratification has gained an increasing role in predicting outcomes and guiding the treatment of patients with pulmonary arterial hypertension (PAH). The most predictive prognostic factors are three noninvasive parameters (World Health Organization functional class, 6-min walk distance and natriuretic peptides) that are included in all currently validated risk stratification tools. However, suffering from limitations mainly related to reduced specificity of PAH severity, these variables may not always be adequate in isolation for guiding individualised treatment decisions. Moreover, with effective combination treatment regimens and emerging PAH therapies, markers associated with pulmonary vascular remodelling are expected to become of increasing relevance in guiding the treatment of patients with PAH. While reaching a low mortality risk, assessed with a validated risk tool, remains an important treatment goal, preliminary data suggest that invasive haemodynamics and cardiac imaging may add incremental value in guiding treatment decisions.

Prognostic utility of exercise cardiovascular magnetic resonance in patients with systemic sclerosis-associated pulmonary arterial hypertension

AIMS

Systemic sclerosis complicated by pulmonary arterial hypertension (SSc-PAH) is a rare condition with poor prognosis. The majority of patients are categorized as intermediate risk of mortality. Cardiovascular magnetic resonance (CMR) is well placed to reproducibly assess right heart size and function, but most patients with SSc-PAH have less overtly abnormal right ventricles than other forms of PAH. The aim of this study was to assess if exercise CMR measures of cardiac size and function could better predict outcome in patients with intermediate risk SSc-PAH compared with resting CMR.

METHODS AND RESULTS

Fifty patients with SSc-PAH categorized as intermediate risk underwent CMR-augmented cardiopulmonary exercise testing. Most patients had normal CMR-defined resting measures of right ventricular (RV) size and function. Nine (18%) patients died during a median follow-up period of 2.1 years (range 0.1-4.6). Peak exercise RV indexed end-systolic volume (ESVi) was the only CMR metric to predict prognosis on stepwise Cox regression analysis, with an optimal threshold < 39 mL/m2 to predict favourable outcome. Intermediate-low risk patients with peak RVESVi < 39 mL/m2 had significantly better survival than all other combinations of intermediate-low/-high risk status and peak RVESVi< or ≥39 mL/m2. In our cohort, ventilatory efficiency and resting oxygen consumption (VO2) were predictive of mortality, but not peak VO2, peak cardiac output, or peak tissue oxygen extraction.

CONCLUSION

Exercise CMR assessment of RV size and function may help identify SSc-PAH patients with poorer prognosis amongst intermediate risk cohorts, even when resting CMR appears reassuring, and could offer added value to clinical PH risk stratification.

The Role of Cardiac MRI in Pulmonary Hypertension- Is it Still an Underutilized Tool

Pulmonary hypertension (PH) is an intricate medical issue resulting from increased pressure in the pulmonary artery (PA). The current gold standard for diagnosis involves an invasive procedure known as right heart catheterization. Nevertheless, cardiac magnetic resonance imaging (cMRI) offers a non-invasive and valuable alternative for evaluating the function, structure, and blood flow through the pulmonary artery (PA) in both the left ventricle (LV) and right ventricle (RV). Additionally, cMRI can be a good tool for predicting mortality by assessing various hemodynamic parameters. We perceive that cMRI may be an underutilized tool in the evaluation of PH. More discussions might be needed to highlight its utility in patients with PH. This article aims to discuss the potential role of cMRI in evaluating PH based on the review of recent literature.

Invasive haemodynamics predict outcomes in paediatric pulmonary artery hypertension

BACKGROUND

Invasive haemodynamics are often performed for initiating and guiding pulmonary artery hypertension therapy. Little is known about the predictive value of invasive haemodynamic indices for long-term outcomes in children with pulmonary artery hypertension. We aimed to evaluate invasive haemodynamic data to help predict outcomes in paediatric pulmonary artery hypertension.

METHODS

Patients with pulmonary artery hypertension who underwent cardiac catheterisation (2006-2019) at a single centre were included. Invasive haemodynamic data from the first cardiac catheterisation and clinical outcomes were reviewed. The combined adverse outcome was defined as pericardial effusion (due to right ventricle failure), creation of a shunt for pulmonary artery hypertension (atrial septal defect or reverse Pott's shunt), lung transplant, or death.

RESULTS

Among 46 patients with a median [interquartile range (IQR)] age of 13.2 [4.1-44.7] months, 76% had CHD. Median mean pulmonary artery pressure was 37 [28-52] mmHg and indexed pulmonary vascular resistance was 6.2 [3.6-10] Woods units × m2. Median pulmonary artery pulsatility index was 4.0 [3.0-4.7] and right ventricular stroke work index was 915 [715-1734] mmHg mL/m2. After a median follow-up of 2.4 years, nine patients had a combined adverse outcome (two had a pericardial effusion, one underwent atrial level shunt, one underwent reverse Pott's shunt, and six died). Patients with an adverse outcome had higher systolic and mean pulmonary artery pressures, higher diastolic and transpulmonary pressure gradients, higher indexed pulmonary vascular resistance, higher pulmonary artery elastance, and higher right ventricular stroke work index (p < 0.05 each).

CONCLUSION

Invasive haemodynamics (especially mean pulmonary artery pressure and diastolic pressure gradient) obtained at first cardiac catheterisation in children with pulmonary artery hypertension predicts outcomes.

Cardiac effort and 6-min walk distance correlate with stroke volume measured by cardiac magnetic resonance imaging

Right ventricular (RV) dysfunction in pulmonary arterial hypertension (PAH) is associated with poor outcomes. Cardiac magnetic resonance imaging (cMRI) is the gold standard for volumetric assessment, and few reports have correlated 6-min walk distance (6MWD) and cMRI parameters in PAH. Cardiac Effort, (the number of heart beats used during 6-min walk test)/(6MWD), incorporates physiologic changes into walk distance and has been associated with stroke volume (SV) measured by nuclear imaging and indirect Fick. Here, we aimed to interrogate the relationship of Cardiac Effort and 6MWD with SV measured by the gold standard, cMRI. This was a single-center, observational, prospective study in Group 1 PAH patients. Subjects completed 6-min walk with heart rate monitoring (Cardiac Effort) and cMRI within 24 h. cMRI was correlated to Cardiac Effort and 6MWD using Spearman Correlation Coefficient. Twenty-five participants with a wide range of RV function completed both cMRI and Cardiac Effort. There was a strong correlation between left ventricle SV index and both Cardiac Effort (r = -0.70, p = 0.0001) and 6MWD (r = 0.67, p = 0.0002). Cardiac Effort and 6MWD were statistically separated in patients at prognostically significant thresholds of left ventricle SV index (>31 ml/m2), RV Ejection Fraction (>35%), and SV/End Systolic Volume ( > 0.53). Cardiac Effort and 6MWD are noninvasive ways to gain insight into those with impaired SV. 6MWD may correlate better with SV than previously thought and heart rate monitoring provides physiologic context to the walk distance obtained.

State-of-the Art Cardiac Magnetic Resonance in Pulmonary Hypertension - An Update on Diagnosis, Risk Stratification and Treatment

Pulmonary hypertension (PH) is a globally under-recognized but life-shortening disease with a poor prognosis if untreated, delayed or inappropriately treated. One of the most important issues for PH is to improve patient quality of life and survival through timely and accurate diagnosis, precise risk stratification and prognosis prediction. Cardiac magnetic resonance (CMR), a non-radioactive, non-invasive image-based examination with excellent tissue characterization, provides a comprehensive assessment of not only the disease severity but also secondary changes in cardiac structure, function and tissue characteristics. The purpose of this review is to illustrate an updated status of CMR for PH assessment, focusing on the application of both conventional and emerging technologies as well as the latest clinical trials.

A computational study of right ventricular mechanics in a rat model of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) presents a significant challenge to right ventricular (RV) function due to progressive pressure overload, necessitating adaptive remodeling in the form of increased wall thickness, enhanced myocardial contractility and stiffness to maintain cardiac performance. However, the impact of these remodeling mechanisms on RV mechanics in not clearly understood. In addition, there is a lack of quantitative understanding of how each mechanism individually influences RV mechanics. Utilizing experimental data from a rat model of PAH at three distinct time points, we developed biventricular finite element models to investigate how RV stress and strain evolved with PAH progression. The finite element models were fitted to hemodynamic and morphological data to represent different disease stages and used to analyze the impact of RV remodeling as well as the altered RV pressure. Furthermore, we performed a number of theoretical simulation studies with different combinations of morphological and physiological remodeling, to assess and quantify their individual impact on overall RV load and function. Our findings revealed a substantial 4-fold increase in RV stiffness and a transient 2-fold rise in contractility, which returned to baseline by week 12. These changes in RV material properties in addition to the 2-fold increase in wall thickness significantly mitigated the increase in wall stress and strain caused by the progressive increase in RV afterload. Despite the PAH-induced cases showing increased wall stress and strain at end-diastole and end-systole compared to the control, our simulations suggest that without the observed remodeling mechanisms, the increase in stress and strain would have been much more pronounced. Our model analysis also indicated that while changes in the RV's material properties-particularly increased RV stiffness - have a notable effect on its mechanics, the primary compensatory factor limiting the stress and strain increase in the early stages of PAH was the significant increase in wall thickness. These findings underscore the importance of RV remodeling in managing the mechanical burden on the right ventricle due to pressure overload.

Effect of Macitentan in Pulmonary Arterial Hypertension and the Relationship Between Echocardiography and cMRI Variables: REPAIR Echocardiography Sub-study Results

INTRODUCTION

The aim of this sub-study was to evaluate the relationship between echocardiography (echo) and cardiac magnetic resonance imaging (cMRI) variables and to utilize echo to assess the effect of macitentan on right ventricle (RV) structure and function.

METHODS

REPAIR (NCT02310672) was a prospective, multicenter, single-arm, open-label, 52-week, phase 4 study in pulmonary arterial hypertension (PAH) patients, which investigated the effect of macitentan 10 mg as monotherapy, or in combination with a phosphodiesterase 5 inhibitor, on RV structure, function, and hemodynamics using cMRI and right heart catheterization. In this sub-study, patients were also assessed by echo at screening and at weeks 26 and/or 52. Post hoc correlation analyses between echo and cMRI variables were performed using Pearson's correlation coefficient, Spearman's correlation coefficient, and Bland-Altman analyses.

RESULTS

The Echo sub-study included 45 patients. Improvements in echo-assessed RV stroke volume (RVSV), left ventricular SV (LVSV), LV end-diastolic volume (LVEDV), RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), and in 2D global longitudinal RV strain (2D GLRVS) were observed at weeks 26 and 52 compared to baseline. There was a strong correlation between echo (LVSV, 2D GLRVS, and LVEDV) and cMRI variables, with a moderate correlation for RVSV. Bland-Altman analyses showed a good agreement for LVSV measured by echo versus cMRI, whereas an overestimation in echo-assessed RVSV was observed compared to cMRI (bias of - 15 mL). Hemodynamic and functional variables, as well as safety, were comparable between the Echo sub-study and REPAIR.

CONCLUSIONS

A good relationship between relevant echo and cMRI parameters was shown. Improvements in RV structure and function with macitentan treatment was observed by echo, consistent with results observed by cMRI in the primary analysis of the REPAIR study. Echo is a valuable complementary method to cMRI, with the potential to non-invasively monitor treatment response at follow-up.

TRIAL REGISTRATION NUMBER

REPAIR NCT02310672.

The ALPHA phase 1 study: pulmonary ArteriaL hypertension treated with CardiosPHere-Derived allogeneic stem cells

BACKGROUND

Pulmonary Arterial Hypertension (PAH) is a progressive condition with no cure. Even with pharmacologic advances, survival remains poor. Lung pathology on PAH therapies still shows impressive occlusive arteriolar remodelling and plexiform lesions. Cardiosphere-derived cells (CDCs) are heart-derived progenitor cells exhibiting anti-inflammatory and immunomodulatory effects, are anti -fibrotic, anti-oxidative and anti-apoptotic to potentially impact several aspects of PAH pathobiology. In preclinical trials CDCs reduced right ventricular (RV) systolic pressure, RV hypertrophy, pulmonary arteriolar wall thickness and inflammation.

METHODS

The ALPHA study was a Phase 1a/b study in which CDCs were infused into patients with Idiopathic (I)PAH, Heritable (H) HPAH, PAH-connective tissue disease (CTD) and PAH-human immunodeficiency virus (HIV). The study was IRB approved and DSMB monitored. Phase 1a, was an open label study (n = 6). Phase 1b was a double-blind placebo-controlled study (n = 20) in which half received 100 million CDCs (the maximum feasible dose from manufacturing perspective) and half placebo (PLAC) infusions. Right heart catheterization (RHC) and cardiac MR imaging (cMR) were performed at baseline and at 4 months post infusion. Patients were followed over a year.

FINDINGS

No short-term clinical safety adverse events (AE) were related to the IP, the primary outcome measure. There were no adverse hemodynamic, gas exchange, rhythm or other clinical events following infusion and in the 1st 23 h monitored in hospital. There were no long-term AEs over 12 months noted, including unrelated limited hospitalizations. No immunologic short or long-term AEs were noted. We examined exploratory outcomes across multiple domains to determine encouraging signals to motivate future advanced phase testing. Phase 1a data showed encouraging observations for both 50 and 100 million CDC doses. Several encouraging findings favouring CDCs (n = 16) compared to placebo (n = 10) were noted. On cMR, the RV end diastolic volume (RVEDV) and index (RVEDVI) decreased with CDCs with a rise in the PLAC group. The 6-min walk distance was increased 2 months post infusion in the CDC group compared with PLAC. With PLAC, diffusing capacity (DLCO) decreased at 4 months but was unchanged with CDCs. Serum creatinine decreased with CDCs at 4 months. Encouraging observations favouring CDCs were also noted for RV fractional area change on echo and RV ejection fraction (RVEF) on cMR at 4 months. No differences were observed for mean pulmonary artery pressures or pulmonary vascular resistance. Review of long-term data to 12 months showed continued decline in DLCO for the PLAC cohort at 6 months with no change through 12 months. By contrast, CDC subjects showed an unchanged DLCO over 12-months. For parameters exhibiting early encouraging exploratory findings in CDC subjects, no further improvement was noted in long-term follow up through 12 months.

INTERPRETATION

Intravenous CDCs were safe in both the short and long term in PAH subjects and thus may be safe in larger cohorts, in line with our extensive track record of safety in clinical trials for other conditions. Further, CDCs exhibited encouraging exploratory findings across several domains. Repeat dosing (quarterly, over one year) of intravenous CDCs has been reported to yield highly significant sustained disease-modifying bioactivity in subjects with advanced Duchenne muscular dystrophy. Because only single CDC doses were used here, the findings represent a lower limit estimate of CDC's potential in PAH. Upcoming phase 2 studies would logically use a repeat dosing paradigm.

FUNDING

California Institute for Regenerative Medicine (CIRM). Project Number: CLIN2-09444.

The association of Pulmonary Hypertension and right ventricular systolic function - updates in diagnosis and treatment

Right ventricular (RV) systolic function is an essential but neglected component in cardiac evaluation, and its importance to the contribution to overall cardiac function is undermined. It is not only sensitive to the effect of left heart valve disease but is also more sensitive to changes in pressure overload than the left ventricle. Pulmonary Hypertension is the common and well-recognized complication of RV systolic dysfunction. It is also the leading cause of pulmonary valve disease and right ventricular dysfunction. Patients with a high pulmonary artery pressure (PAP) and a low RV ejection fraction have a seven-fold higher risk of death than heart failure patients with a normal PAP and RV ejection fraction. Furthermore, it is an independent predictor of survival in these patients. In this review, we examine the association of right ventricular systolic function with Pulmonary Hypertension by focusing on various pathological and clinical manifestations while assessing their impact. We also explore new 2022 ESC/ERS guidelines for diagnosing and treating right ventricular dysfunction in Pulmonary Hypertension.

Comparison of cardiac magnetic resonance imaging, functional and haemodynamic variables in pulmonary arterial hypertension: insights from REPAIR

Background

Measures that can detect large treatment effects are important for monitoring therapeutic effectiveness. The 2022 European Society of Cardiology/European Respiratory Society guidelines highlight the importance of imaging in monitoring disease status and treatment response in pulmonary arterial hypertension (PAH). Are the standardised treatment effect sizes (STES) of cardiac magnetic resonance imaging (cMRI) comparable with functional and haemodynamic variables?

Methods

REPAIR (ClinicalTrials.gov: NCT02310672) was a prospective, multicentre, single-arm, open-label, 52-week phase 4 study evaluating the effect of macitentan 10 mg, with or without a phosphodiesterase 5 inhibitor (PDE5i), on right ventricular (RV) remodelling, cardiac function and cardiopulmonary haemodynamics. Both cMRI and functional assessments were performed at screening and at weeks 26 and 52; haemodynamic measurements were conducted at screening and week 26. In this post hoc analysis, STES were estimated using the parametric Cohen's d and non-parametric Cliff's delta tests.

Results

At week 26, large STES (Cohen's d) were observed for 10 of the 20 cMRI variables assessed, including the prognostic measures of RV and left ventricular stroke volume and RV ejection fraction and the haemodynamic trial end-point, pulmonary vascular resistance; medium STES were observed for 6-min walk distance (6MWD). The STES were consistent in treatment-naïve patients and those escalating therapy and maintained at week 52. Similar results were obtained using the non-parametric Cliff's delta method.

Conclusions

The treatment effect of macitentan, alone or in combination with a PDE5i, was comparable for several cMRI and haemodynamic variables with prognostic value in PAH, and greater than that of 6MWD in patients with PAH, highlighting the emerging relevance of cMRI in PAH.

Toward the Implementation of Optimal Cardiac Magnetic Resonance Risk Stratification in Pulmonary Arterial Hypertension

BACKGROUND

The 2022 European Society of Cardiology/European Respiratory Society pulmonary hypertension (PH) guidelines incorporate cardiac magnetic resonance (CMR) imaging metrics in the risk stratification of patients with pulmonary arterial hypertension (PAH). Thresholds to identify patients at estimated 1-year mortality risks of < 5%, 5% to 20%, and > 20% are introduced. However, these cutoff values are mostly single center-based and require external validation.

RESEARCH QUESTION

What are the discriminative prognostic properties of the current CMR risk thresholds stratifying patients with PAH?

STUDY DESIGN AND METHODS

We analyzed data from incident, treatment-naïve patients with PAH from the Amsterdam University Medical Centres, Vrije Universiteit, The Netherlands. The discriminative properties of the proposed CMR three risk strata were tested at baseline and first reassessment, using the following PH guideline variables: right ventricular ejection fraction, indexed right ventricular end-systolic volume, and indexed left ventricular stroke volume.

RESULTS

A total of 258 patients with PAH diagnosed between 2001 and 2022 fulfilled the study criteria and were included in this study. Of these, 172 had follow-up CMR imaging after 3 months to 1.5 years. According to the CMR three risk strata, most patients were classified at intermediate risk (n = 115 [45%]) upon diagnosis. Only 29 (11%) of patients with PAH were classified at low risk, and 114 (44%) were classified at high risk. Poor survival discrimination was seen between risk groups. Appropriate survival discrimination was seen at first reassessment.

INTERPRETATION

Risk stratifying patients with PAH with the recent proposed CMR cutoffs from the European Society of Cardiology/European Respiratory Society 2022 PH guidelines requires adjustment because post-processing consensus is lacking and general applicability is limited. Risk assessment at follow-up yielded better survival discrimination, emphasizing the importance of the individual treatment response.

The Right Ventricle in Pulmonary Hypertension

The right ventricle plays a pivotal role in patients with pulmonary hypertension (PH). Its adaptation to pressure overload determines a patient's functional status as well as survival. In a healthy situation, the right ventricle is part of a low pressure, high compliance system. It is built to accommodate changes in preload, but not very well suited for dealing with pressure overload. In PH, right ventricular (RV) contractility must increase to maintain cardiac output. In other words, the balance between the degree of RV contractility and afterload determines stroke volume. Hypertrophy is one of the major hallmarks of RV adaptation, but it may cause stiffening of the ventricle in addition to intrinsic changes to the RV myocardium. Ventricular filling becomes more difficult for which the right atrium tries to compensate through increased stroke work. Interaction of RV diastolic stiffness and right atrial (RA) function determines RV filling, but also causes vena cava backflow. Assessment of RV and RA function is critical in the evaluation of patient status. In recent guidelines, this is acknowledged by incorporating additional RV parameters in the risk stratification in PH. Several conventional parameters of RV and RA function have been part of risk stratification for many years. Understanding the pathophysiology of RV failure and the interactions with the pulmonary circulation and right atrium requires consideration of the unique RV anatomy. This review will therefore describe normal RV structure and function and changes that occur during adaptation to increased afterload. Consequences of a failing right ventricle and its implications for RA function will be discussed. Subsequently, we will describe RV and RA assessment in clinical practice.

Heart Failure Preserved Ejection Fraction in Women: Insights Learned from Imaging

While the prevalence of heart failure, in general, is similar in men and women, women experience a higher rate of HFpEF compared to HFrEF. Cardiovascular risk factors, parity, estrogen levels, cardiac physiology, and altered response to the immune system may be at the root of this difference. Studies have found that in response to increasing age and hypertension, women experience more concentric left ventricle remodeling, more ventricular and arterial stiffness, and less ventricular dilation compared to men, which predisposes women to developing more diastolic dysfunction. A multi-modality imaging approach is recommended to identify patients with HFpEF. Particularly, appreciation of sex-based differences as described in this review is important in optimizing the evaluation and care of women with HFpEF.

Left ventricular underfilling in PAH: A potential indicator for adaptive-to-maladaptive transition

Pulmonary arterial hypertension (PAH) still remains a life-threatening disorder with poor prognosis. The right ventricle (RV) adapts to the increased afterload by a series of prognostically significant morphological and functional changes, the adaptive nature should also be understood in the context of ventricular interdependence. We hypothesized that left ventricle (LV) underfilling could serve as an important imaging marker for identifying maladaptive changes and predicting clinical outcomes in PAH patients. We prospectively enrolled patients with PAH who underwent both cardiac magnetic resonance and right heart catheterization between October 2013 and December 2020. Patients were categorized into four groups based on their LV and RV mass/volume ratio (M/V). LV M/V was stratified using the normal value (0.7 g/mL for males and 0.6 g/mL for females) to identify patients with LV underfilling (M/V ≥ normal value), while RV M/V was stratified based on the median value. The primary endpoint was all-cause mortality, and the composite endpoints included all-cause mortality and heart failure-related readmissions. A total of 190 PAH patients (53 male, mean age 37 years) were included in this study. Patients with LV underfilling exhibited higher NT-proBNP levels, increased RV mass, larger RV but smaller LV, lower right ventricular ejection fraction, and shorter 6-min walking distance. Patients with LV underfilling had a 2.7-fold higher risk of mortality than those without and LV M/V (hazard ratio [per 0.1 g/mL increase]: 1.271, 95% confidence interval: 1.082-1.494, p = 0.004) was also independent predictors of all-cause mortality. Moreover, patients with low LV M/V had a better prognosis regardless of the level of RV M/V. Thus, LV underfilling is an independent predictor of adverse clinical outcomes in patients with PAH, and it could be an important imaging marker for identifying maladaptive changes in these patients.

Right ventricular assessment in pulmonary hypertension

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of assessment of right ventricular function in the context of pulmonary hypertension and pulmonary arterial hypertension (PAH). We will review unique features of right ventricular anatomy, delineation of cause of pulmonary hypertension through careful right ventricular assessment, echocardiographic and hemodynamic evaluation, and the importance of this assessment in prognosis.

RECENT FINDINGS

The importance of performance in prognosis and risk assessment in patients with pulmonary hypertension has been continually emphasized in ongoing research. Representative parameters of right ventricular function have been shown to be predictive of prognosis in patients with pulmonary hypertension. Further, the importance of serial right ventricular assessment in risk assessment and prognosis has remained an emerging theme.

SUMMARY

Careful evaluation of right ventricular function is paramount in assessing the cause of pulmonary hypertension and severity of disease. Further, it has prognostic significance, as many representative parameters of right ventricular function have been linked with mortality. In our opinion, right ventricular function should be assessed serially throughout the course of treatment in pulmonary hypertension, and baseline parameters in addition to dynamic changes should be incorporated into risk assessment. Achieving normal or near-normal right ventricular performance may serve as a principal goal in the treatment of pulmonary hypertension.

Treatment of pulmonary arterial hypertension: recent progress and a look to the future

Pulmonary arterial hypertension (PAH) is a severe but treatable form of pre-capillary pulmonary hypertension caused by pulmonary vascular remodelling. As a result of basic science discoveries, randomised controlled trials, studies of real-world data, and the development of clinical practice guidelines, considerable progress has been made in the treatment options and outcomes for patients with PAH, underscoring the importance of seamless translation of information from bench to bedside and, ultimately, to patients. However, PAH still carries a high mortality rate, which emphasises the urgent need for transformative innovations in the field. In this Series paper, written by a group of clinicians, researchers, and a patient with PAH, we review therapeutic approaches and treatment options for PAH. We summarise current knowledge of the cellular and molecular mechanisms of PAH, with an emphasis on emerging treatable pathways and optimisation of current management strategies. In considering future directions for the field, our ambition is to identify therapies with the potential to stall or reverse pulmonary vascular remodelling. We highlight novel therapeutic approaches, the important role of patients as partners in research, and innovative approaches to PAH clinical trials.

Ventricular global function index is associated with clinical outcomes in pediatric pulmonary hypertension

BACKGROUND

Multiple right ventricular (RV) metrics have prognostic value in pulmonary hypertension (PH). A cardiac magnetic resonance imaging (CMR) derived global ventricular function index (GFI) provided improved prediction of composite adverse outcome (CAO) in adults with atherosclerosis. GFI has not yet been explored in a PH population. We explored the feasibility of GFI as a predictor of CAO in a pediatric PH population.

METHODS

Two center retrospective chart review identified pediatric PH patients undergoing CMR from Jan 2005-June 2021. GFI, defined as the ratio of the stroke volume to the sum of mean ventricular cavity and myocardial volume, was calculated for each patient. CAO was defined as death, lung transplant, Potts shunt, or parenteral prostacyclin initiation after CMR. Cox proportional hazards regression was used to estimate associations and assess model performance between CMR parameters and CAO.

RESULTS

The cohort comprised 89 patients (54% female, 84% World Health Organization (WHO) Group 1; 70% WHO-FC ≤ 2; and 27% on parenteral prostacyclin). Median age at CMR was 12 years (IQR 8.1-17). Twenty-one (24%) patients experienced CAO during median follow up of 1.5 years. CAO cohort had higher indexed RV volumes (end systolic-145 vs 99 mL/m2, p = 0.003; end diastolic-89 vs 46 mL/m2, p = 0.004) and mass (37 vs 24 gm/m2, p = 0.003), but lower ejection fraction (EF) (42 vs 51%, p < 0.001) and GFI (40 vs 52%, p < 0.001). Higher indexed RV volumes (hazard ratios [HR] 1.01, CI 1.01-1.02), lower RV EF (HR 1.09, CI 1.05-1.12) and lower RV GFI (HR 1.09, CI 1.05-1.11) were associated with increased risk of CAO. In survival analysis, patients with RV GFI < 43% demonstrated decreased event-free survival and increased hazard of CAO compared to those with RV GFI ≥ 43%. In multivariable models, inclusion of GFI provided improved prediction of CAO compared to models incorporating ventricular volumes, mass or EF.

CONCLUSIONS

RV GFI was associated with CAO in this cohort, and inclusion in multivariable models had increased predictive value compared to RVEF. GFI uses readily available CMR data without additional post-processing and may provide additional prognostic value in pediatric PH patients beyond traditional CMR markers.

The emerging role of sacubitril/valsartan in pulmonary hypertension with heart failure

Pulmonary hypertension due to left heart disease (PH-LHD) represents approximately 65%-80% of all patients with PH. The progression, prognosis, and mortality of individuals with left heart failure (LHF) are significantly influenced by PH and right ventricular (RV) dysfunction. Consequently, cardiologists should devote ample attention to the interplay between HF and PH. Patients with PH and HF may not receive optimal benefits from the therapeutic effects of prostaglandins, endothelin receptor antagonists, or phosphodiesterase inhibitors, which are specific drugs for pulmonary arterial hypertension (PAH). Sacubitril/valsartan, the angiotensin receptor II blocker-neprilysin inhibitor (ARNI), was recommended as the first-line therapy for patients with heart failure with reduced ejection fraction (HFrEF) by the 2021 European Society of Cardiology Guidelines. Although ARNI is effective in treating left ventricular (LV) enlargement and lower ejection fraction, its efficacy in treating individuals with PH and HF remains underexplored. Considering its vasodilatory effect at the pre-capillary level and a natriuretic drainage role at the post-capillary level, ARNI is believed to have a broad range of potential applications in treating PH-LHD. This review discusses the fundamental pathophysiological connections between PH and HF, emphasizing the latest research and potential benefits of ARNI in PH with various types of LHF and RV dysfunction.

Multimodality Imaging of Right Heart Function: JACC Scientific Statement

Right ventricular (RV) size and function assessed by multimodality imaging are associated with outcomes in a variety of cardiovascular diseases. Understanding RV anatomy and physiology is essential in appreciating the strengths and weaknesses of current imaging methods and gives these measurements greater context. The adaptation of the right ventricle to different types and severity of stress, particularly over time, is specific to the cardiovascular disease process. Multimodality imaging parameters, which determine outcomes, reflect the ability to image the initial and longitudinal RV response to stress. This paper will review the standard and novel imaging methods for assessing RV function and the impact of these parameters on outcomes in specific disease states.

The heart of the matter: Right heart imaging indicators for treatment escalation in pulmonary arterial hypertension

Right heart (RH) structure and function are major determinants of symptoms and prognosis in pulmonary arterial hypertension (PAH). RH imaging provides detailed information, but evidence and guidelines on the use of RH imaging in treatment decisions are limited. We conducted a Delphi study to gather expert opinion on the role of RH imaging in decision-making for treatment escalation in PAH. A panel of 17 physicians with expertise in PAH and RH imaging used three surveys in a modified Delphi process to reach consensus on the role of RH imaging in PAH. Survey 1 used open-ended questions to gather information. Survey 2 contained Likert scale and other questions intended to identify consensus on topics identified in Survey 1. Survey 3 contained Likert scale questions derived from Survey 2 and summary information on the results of Survey 2. The Delphi panel reached consensus that RH imaging is likely to improve the current risk stratification algorithms and help differentiate risk levels in patients at intermediate risk. Tricuspid annular plane systolic excursion, right ventricular fractional area change, right atrial area, tricuspid regurgitation, inferior venae cavae diameter, and pericardial effusion should be part of routine echocardiography in PAH. Cardiac magnetic resonance imaging is valuable but limited by cost and access. A pattern of abnormal RH imaging results should prompt consideration of hemodynamic evaluation and possible treatment escalation. RH imaging is an important tool for decisions about treatment escalation in PAH, but systematically collected evidence is needed to clarify its role.

The right ventricle in tetralogy of Fallot: adaptation to sequential loading

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

Potential Prognostic Value of Native T1 in Pulmonary Hypertension Patients

Native T1, extracellular volume fraction (ECV), and late gadolinium enhancement (LGE) characterize myocardial tissue and relate to patient prognosis in a variety of diseases, including pulmonary hypertension. The purpose of this study was to evaluate if left ventricle (LV) fibrosis measurements have prognostic value for cardiac outcomes in pulmonary hypertension subgroups. 54 patients with suspected pulmonary hypertension underwent right-heart catheterization and were classified into pulmonary hypertension subgroups: pre-capillary component (PreCompPH) and isolated post-capillary (IpcPH). Cardiac magnetic resonance imaging (MRI) scans were performed with the acquisition of balanced cine steady-state free precession, native T1, and LGE pulse sequences to measure cardiac volumes and myocardial fibrosis. Associations between cardiac events and cardiac MRI measurements were analyzed within PreCompPH and IpcPH patients. IpcPH: LV native T1 was higher in patients who experienced a cardiac event within two years vs. those who did not. In patients with LV native T1 > 1050 ms, the rate of cardiac events was higher. ECV and quantitative LGE did not differ between groups. PreCompPH: native T1, ECV, and quantitative/qualitative LGE did not differ between patients who experienced a cardiac event within two years vs. those who did not. LV native T1 may have potential value for forecasting cardiac events in IpcPH, but not in PreCompPH, patients.

Risk Stratification and Outcomes in Patients With Pulmonary Hypertension: Insights into Right Ventricular Strain by MRI Feature tracking

BACKGROUND

Despite a recommended multidimensional approach for pulmonary hypertension (PH) risk stratification and guidance of treatment decisions, this may not always be achievable in patients with advanced disease. One issue is the lack of an imaging modality to assess right ventricular (RV) structure and function abnormalities.

PURPOSE

To explore the risk stratification and prognostic value of cardiac MR feature tracking (MR-FT)-derived RV strain.

STUDY TYPE

Retrospective.

POPULATION

A total of 80 patients with idiopathic pulmonary artery hypertension (N = 52) or chronic thromboembolic PH (N = 28).

FIELD STRENGTH

A 1.5 T or 3.0 T, balanced steady-state free precession sequence.

ASSESSMENT

All patients underwent laboratory testing, right heart catheterization, and MR imaging (and in 37 cases, a cardiopulmonary exercise test was also performed) within a 1-month period. Cardiac functional parameters and both global longitudinal strain (GLS) and global circumferential strain (GCS) were analyzed. Patients were stratified into low, intermediate, and high-risk groups by guideline suggested stratified values of risk factors. The combined endpoint was death or hospitalization for congestive heart failure assessed during follow-up since the date of MR examination.

STATISTICAL TESTS

Kolmogorov-Smirnov's test, independent-sample t-tests, Wilcoxon's rank-sum tests, one-way analysis of variance, χ² tests or Fisher's exact test, receiver operating characteristic analysis, Kaplan-Meier survival analysis, and Cox regression analysis. A P value < 0.05 was considered statistically significant.

RESULTS

The median follow-up duration was 3.4 years. Thirty-five patients presented with combined endpoint including 10 cardiac deaths. RV structural and deformation impairments were significantly associated with combined endpoint (ejection fraction: 31.3% ± 13.2% vs. 38.0% ± 14.8%, hazard ratio [HR: 0.974; GLS: -14.5 [-18.6, -10.9] % vs. -20.4 [-26.0, -13.2] %, HR: 1.071; GCS: -9.8 [-14.5, -7.3] % vs. -12.3 [-19.9, -8.4] %, HR: 1.059). There were significant differences in RVGLS among low, intermediate, and high-risk groups (-19.3% ± 7.2% vs. -17.3% ± 9.4% vs. -11.5% ± 4.4% by cardiac functional class, -21.8% ± 7.3% vs. -19.4% ± 8.2% vs. -12.7 ± 5.3% by NT-proBNP, -19.7% ± 7.7 vs. -15.8% ± 6.5% vs. -12.6% ± 8.2% by cardiac index).

DATA CONCLUSION

RV deformation may aid risk stratification in patients with PH, providing crucial information for RV remodeling, pulmonary hemodynamic condition and exercise capacity.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Riociguat and the right ventricle in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are progressive diseases that can lead to right heart failure and death. Right ventricular dysfunction, hypertrophy and maladaptive remodelling are consequences of increased right ventricular (RV) afterload in PAH and CTEPH and are indicative of long-term outcomes. Because RV failure is the main cause of morbidity and mortality in PAH and CTEPH, successful treatments should lead to improvements in RV parameters. Riociguat is a soluble guanylate cyclase stimulator approved for the treatment of PAH and inoperable or persistent/recurrent CTEPH after pulmonary endarterectomy. This review examines the current evidence showing the effect of riociguat on the right ventricle, with particular focus on remodelling, function and structural parameters in preclinical models and patients with PAH or CTEPH.

Apply pressure-strain loop to quantify myocardial work in pulmonary hypertension: A prospective cohort study

Objectives

Pressure-strain loop (PSL) is a novel method to quantify myocardial work in many cardiovascular diseases. To investigate the value of myocardial work parameters derived from PSL for evaluating cardiac function and clinical prognosis in patients with pulmonary hypertension (PH).

Methods

A total of 52 patients with PH and 27 healthy controls were enrolled in this prospective study. PSLs determined by echocardiography were used to calculate global work index (GWI) of left ventricle (LV) and right ventricle (RV). Global constructive work (GCW) comprised the sum of myocardial work performed during shortening in systole and during lengthening in isovolumic relaxation. Global wasted work (GWW) comprised the sum of myocardial work performed during lengthening in systole and during shortening in isovolumic relaxation. Global work efficiency (GWE) was defined as GCW/(GCW + GWW).

Results

LVGWW, RVGWI, RVGCW and RVGWW were significantly higher in patients than controls (all P < 0.001). LVGWE, LVGWI, LVGCW, and RVGWE were lower in patients than controls (all P < 0.01). Myocardial work parameters correlated well with clinical and other conventional echocardiographic assessments (all P < 0.05). In binary logistic regression analysis, the combination of RVGWE and estimation of pulmonary arterial systolic pressure (ePASP) was the best model to predict clinical outcomes (OR = 0.803, P = 0.002 and OR = 1.052, P = 0.015, respectively). Receiver operating characteristic curv demonstrated the combination of RVGWE and ePASP was the best predictor of adverse events with 100% sensitivity and 76.3% specificity (AUC = 0.910, P < 0.001).

Conclusion

Myocardial work parameters derived from PSL are emerging markers of cardiac function. And the combination of RVGWE and ePASP is a useful predictor of clinical outcome in PH patients.

Heart recovery and reverse remodeling following lung transplant in pulmonary artery hypertension

Background

Pulmonary artery hypertension (PAH) is a progressive disease that result in right heart dysfunction. Lung transplantation (LTx) improve survival in end-stage disease. The aim of this study is to assess heart recovery after LTx for patients with primary and secondary pulmonary hypertension.

Methods

We conducted a single center retrospective review for patients with primary and secondary PAH underwent LTx between the period of January 2015 and December 2020. Baseline characteristics and echocardiographic measures were assessed pre-operative and after 1 year follow-up. Survival comparison between primary and secondary PAH was estimated by Kaplan–Meier method.

Results

We identified 43 participants for the study. Among the participants, 11 case had primary PAH. Median age during transplant was 60 years (45.5, 65.5). Left atrium anterio-posterior dimensions, systolic right ventricle pressure tricuspid peal regurgitant velocity and severity of tricuspid regurgitation were found to be significantly improved post-operatively compared to pre-operative echocardiography (p value < 0.05). Overall mortality was not significant between primary and secondary PAH (p value = 0.66).

Conclusions

LTx can reverse heart remodeling and facilitate recovery in primary and secondary PAH. Our data confirm the importance of LTx as a viable option in PAH failing medical treatment.

Increased biventricular hemodynamic forces in precapillary pulmonary hypertension

Precapillary pulmonary hypertension (PHprecap) is a condition with elevated pulmonary vascular pressure and resistance. Patients have a poor prognosis and understanding the underlying pathophysiological mechanisms is crucial to guide and improve treatment. Ventricular hemodynamic forces (HDF) are a potential early marker of cardiac dysfunction, which may improve evaluation of treatment effect. Therefore, we aimed to investigate if HDF differ in patients with PHprecap compared to healthy controls. Patients with PHprecap (n = 20) and age- and sex-matched healthy controls (n = 12) underwent cardiac magnetic resonance imaging including 4D flow. Biventricular HDF were computed in three spatial directions throughout the cardiac cycle using the Navier-Stokes equations. Biventricular HDF (N) indexed to stroke volume (l) were larger in patients than controls in all three directions. Data is presented as median N/l for patients vs controls. In the RV, systolic HDF diaphragm-outflow tract were 2.1 vs 1.4 (p = 0.003), and septum-free wall 0.64 vs 0.42 (p = 0.007). Diastolic RV HDF apex-base were 1.4 vs 0.87 (p < 0.0001), diaphragm-outflow tract 0.80 vs 0.47 (p = 0.005), and septum-free wall 0.60 vs 0.38 (p = 0.003). In the LV, systolic HDF apex-base were 2.1 vs 1.5 (p = 0.005), and lateral wall-septum 1.5 vs 1.2 (p = 0.02). Diastolic LV HDF apex-base were 1.6 vs 1.2 (p = 0.008), and inferior-anterior 0.46 vs 0.24 (p = 0.02). Hemodynamic force analysis conveys information of pathological cardiac pumping mechanisms complementary to more established volumetric and functional parameters in precapillary pulmonary hypertension. The right ventricle compensates for the increased afterload in part by augmenting transverse forces, and left ventricular hemodynamic abnormalities are mainly a result of underfilling rather than intrinsic ventricular dysfunction.

Computational modelling of multi-temporal ventricular-vascular interactions during the progression of pulmonary arterial hypertension

A computational framework is developed to consider the concurrent growth and remodelling (G&R) processes occurring in the large pulmonary artery (PA) and right ventricle (RV), as well as ventricular-vascular interactions during the progression of pulmonary arterial hypertension (PAH). This computational framework couples the RV and the proximal PA in a closed-loop circulatory system that operates in a short timescale of a cardiac cycle, and evolves over a long timescale due to G&R processes in the PA and RV. The framework predicts changes in haemodynamics (e.g. 68.2% increase in mean PA pressure), RV geometry (e.g. 38% increase in RV end-diastolic volume) and PA tissue microstructure (e.g. 90% increase in collagen mass) that are consistent with clinical and experimental measurements of PAH. The framework also predicts that a reduction in RV contractility is associated with long-term RV chamber dilation, a common biomarker observed in the late-stage PAH. Sensitivity analyses on the G&R rate constants show that large PA stiffening (both short and long term) is affected by RV remodelling more than the reverse. This framework can serve as a foundation for the future development of a more predictive and comprehensive cardiovascular G&R model with realistic heart and vascular geometries.

Atrioventricular plane displacement and regional function to predict outcome in pulmonary arterial hypertension

To investigate if left and right atrioventricular plane displacement (AVPD) or regional contributions to SV are prognostic for outcome in patients with pulmonary arterial hypertension (PAH). Seventy-one patients with PAH and 20 sex- and age-matched healthy controls underwent CMR. Myocardial borders and RV insertion points were defined at end diastole and end systole in cine short-axis stacks to compute biventricular volumes, lateral (SVlat%) and septal (SVsept%) contribution to stroke volume. Eight atrioventricular points were defined at end diastole and end systole in 2-, 3- and 4-chamber cine long-axis views for computation of AVPD and longitudinal contribution to stroke volume (SVlong%). Cut-off values for survival analysis were defined as two standard deviations above or below the mean of the controls. Outcome was defined as death or lung transplantation. Median follow-up time was 3.6 [IQR 3.7] years. Patients were 57 ± 19 years (65% women) and controls 58 ± 15 years (70% women). Biventricular AVPD, SVlong% and ejection fraction (EF) were lower and SVlat% was higher, while SVsept% was lower in PAH compared with controls. In PAH, transplantation-free survival was lower below cut-off for LV-AVPD (hazard ratio [HR] = 2.1, 95%CI 1.2-3.9, p = 0.02) and RV-AVPD (HR = 9.8, 95%CI 4.6-21.1, p = 0.005). In Cox regression analysis, lower LV-AVPD and RV-AVPD inferred lower transplantation-free survival (LV: HR = 1.16, p = 0.007; RV: HR = 1.11, p = 0.01; per mm decrease). LV-SVlong%, RV-SVlong%, LV-SVlat%, RV-SVlat%, SVsept% and LV- and RVEF did not affect outcome. Low left and right AVPD were associated with outcome in PAH, but regional contributions to stroke volume and EF were not.

Long-term prognostic value of cardiac catheterization and acute vasodilator testing with inhaled iloprost in pediatric idiopathic pulmonary arterial hypertension

To assess the long-term prognostic value of cardiac catheterization and acute vasodilator testing (AVT) with inhaled iloprost in children with idiopathic pulmonary arterial hypertension (IPAH). Data on 81 consecutive children with IPAH referred to our center who underwent cardiac catheterization and AVT between June 2008 and August 2019 were collected. The correlation between the invasive hemodynamic data and transplant-free survival was analyzed. Twenty-four patients died and 1 underwent lung transplantation during a median follow-up of 3.8 years, with a 5-year transplant-free survival rate of 64.9%. Univariate analysis showed that predictors associated with improved survival included a lower pulmonary vascular resistance index (PVRI), PVRI/systemic vascular resistance index (SVRI), mean pulmonary arterial pressure (mPAP)/mean systemic arterial pressure, mean right atrial pressure, and a higher cardiac index (CI), mixed systemic venous oxygen saturations (SvO2), and acute vasodilator response (AVR) according to the Barst criteria (decrease in mPAP and PVRI/SVRI ratio of >20% without a decrease in CI). In multivariate Cox regression analysis, Barst AVR and SvO2 were independently related to transplant-free survival. Multiple hemodynamic variables from cardiac catheterization and AVT with inhaled iloprost have important prognostic value for long-term survival in children with IPAH, of which pulmonary vasoreactivity defined by the Barst criteria and SvO2 are independent prognostic factors.

Proteomic and Metabolomic Analyses of Right Ventricular Failure due to Pulmonary Arterial Hypertension

Right ventricular failure (RVF) is the independent and strongest predictor of mortality in pulmonary arterial hypertension (PAH), but, at present, there are no preventive and therapeutic strategies directly targeting the failing right ventricle (RV). The underlying mechanism of RV hypertrophy (RVH) and dysfunction needs to be explored in depth. In this study, we used myocardial proteomics combined with metabolomics to elucidate potential pathophysiological changes of RV remodeling in a monocrotaline (MCT)-induced PAH rat model. The proteins and metabolites extracted from the RV myocardium were identified using label-free liquid chromatography–tandem mass spectrometry (LC-MS/MS). The bioinformatic analysis indicated that elevated intracellular Ca²⁺ concentrations and inflammation may contribute to myocardial proliferation and contraction, which may be beneficial for maintaining the compensated state of the RV. In the RVF stage, ferroptosis, mitochondrial metabolic shift, and insulin resistance are significantly involved. Dysregulated iron homeostasis, glutathione metabolism, and lipid peroxidation related to ferroptosis may contribute to RV decompensation. In conclusion, we depicted a proteomic and metabolomic profile of the RV myocardium during the progression of MCT-induced PAH, and also provided the insights for potential therapeutic targets facilitating the retardation or reversal of RV dysfunction in PAH.

Exploring the failing right ventricle in pulmonary hypertension by cardiac magnetic resonance: An in vivo study utilizing Macitentan

Cardiac magnetic resonance (CMR) imaging is used to assess the right ventricle (RV) of pulmonary hypertensive (PH) patients and more recently to track changes in response to therapy. We wished to investigate if repeat CMRs could be used to assess ventricular changes in the Sugen 5416 hypoxic (Su/Hx) rat model of PH treated with the dual endothelin receptor antagonist Macitentan. Male Sprague Dawley Su/Hx rats were dosed for 3 weeks with either vehicle or Macitentan (30 mg/kg) daily, control rats received only vehicle. All rats underwent three CMR scans; before treatment, 2 weeks into treatment, and end of the study. A separate group of Su/Hx and control rats, treated as above, underwent terminal hemodynamic measurements. Using terminal and CMR measurements, Macitentan was found to lower RV systolic pressure pulmonary artery remodeling and increase RV ejection fraction but not change RV hypertrophy (RVH). Repeat CMRs determined that Su/Hx rats treated with Macitentan had significantly reversed RVH via reducing RV mass as well as reducing elevated left ventricular eccentricity index; reductions in RV mass were also observed in Su/Hx vehicle rats exposed to normoxic conditions. We have demonstrated that repeat CMRs can be used to assess the volume and structural changes in the ventricles of the Su/Hx rat model. Using repeat CMRs has allowed us to build a more complete picture of the response of the RV and the left ventricle to treatment. It is unknown if these effects are a consequence of direct action on the RV or secondary to improvements in the lung vasculature.

Clinically important changes in right ventricular volume and function in pulmonary arterial hypertension assessed with cardiac magnetic resonance imaging

Right ventricular (RV) dilatation predicts clinical worsening in pulmonary arterial hypertension (PAH) and RV volumes can be measured with high precision using cardiovascular magnetic resonance imaging. In regular follow-up of patients and in studies of improvement in RV function, knowledge of clinically significant changes of RV volumes and function are of relevance. Patients with PAH were followed with cardiovascular magnetic resonance imaging and clinical assessment at 6-month intervals. Changes in RV volumes associated with changes in clinical status were assessed. Twenty-five patients with PAH (Group 1) were included and examined every 6 months for 2.5 years, with a total of 107 MRI scans. For a step change in WHO functional class, the associated change in RV volume was 11% (confidence interval 7%-14%, p < 0.0001) and in stroke volume 9% (confidence interval 3%-15%, p = 0.003). This study found an 11% change in RV volume to be clinically significant. The combination of clinically significant changes and the known precision in the measurements enables individualized follow-up of RV-function in PAH. To our knowledge, this study is the first to use repeated assessments to suggest clinically significant changes of RV volume based on changes in clinical presentation.

Time-Velocity Integral of Left Ventricular Outflow Tract Predicts Worse Long-Term Survival in Pulmonary Arterial Hypertension

BACKGROUND

The time-velocity integral of the left ventricular outflow tract (TVI_LVOT) has been demonstrated to correlate with heart failure hospitalization and mortality, but the association of TVI_LVOT with the severity and prognosis of pulmonary arterial hypertension (PAH) has not been evaluated.

OBJECTIVES

The aim of this study was to investigate the predictive value of baseline TVI_LVOT in PAH.

METHODS

A total of 225 consecutive patients with a diagnosis of incident PAH were prospectively studied and echocardiology-derived TVI_LVOT was measured at enrollment followed by right heart catheterization examination within 48 hours. Cox proportional hazards analysis was performed to assess the association between baseline variables and mortality.

RESULTS

During a median follow-up period of 33.8 months, 44 patients died of cardiovascular events. Baseline TVI_LVOT was significantly lower in the nonsurvivors compared with the survivors (P < 0.001). Baseline TVI_LVOT was positively correlated with stroke volume obtained by right heart catheterization (r = 0.709; P < 0.001), and inversely correlated with N-terminal pro-B-type natriuretic peptide (r = -0.533; P < 0.001), pulmonary vascular resistance (r = -0.423; P < 0.001). Multivariate analysis showed that baseline TVI_LVOT (hazard ratio: 0.856; 95% CI: 0.780-0.941; P = 0.001) was an independent predictor of cardiovascular mortality in PAH. Patients with a baseline TVI_LVOT <17.1 cm (median value) had a significantly worse survival than those with a baseline TVI_LVOT ≥17.1 cm (P < 0.001).

CONCLUSIONS

The findings of this study suggest that noninvasive TVI_LVOT provides a practical method to assess the severity and predict long-term outcome of PAH.

A Study of the Efficacy and Safety of Aerobic Exercise Training in Pulmonary Arterial Hypertension (the Saturday Study): Protocol for a Prospective, Randomized, and Controlled Trial

Background

Patients with pulmonary arterial hypertension (PAH) have reduced exercise capacity and poor quality of life. Exercise-based rehabilitation in PAH results in clinically relevant improvements in exercise capacity and hemodynamics. To clarify the mechanism, we will evaluate the effect of aerobic exercise training rehabilitation on right ventricular (RV) remodeling and function as determined measured by cardiac magnetic resonance imaging (CMR).

Methods

We will conduct a 26-week multicenter randomized controlled trial. Patients on stable and unchanged PAH-targeted medication are randomly assigned (1:1) to the control and training groups. The primary endpoint is the RV stroke volume (RVSV) change from baseline to Week 26, determined by CMR. Comprehensive RV function is also performed using CMR. Other characteristics of the RV and left ventricle, World Health Organization functional class, 6-min walk distance, and N-terminal pro-B-type natriuretic peptide are included in secondary endpoints. We also investigate the proteomic, metabolomic, and transcriptomic changes after exercise training as exploratory endpoints.

Ethics and Dissemination

The study and protocol were approved by the Ethics Committee of Shanghai Pulmonary Hospital (Approved No. of ethics committee: L20-17). The results will be disseminated at medical conferences and in journal publications. All participants will sign written informed consent.

Trial Registration Number

ChiCTR2000031650.

Mineralocorticoid receptor antagonist treatment of established pulmonary arterial hypertension improves interventricular dependence in the SU5416-hypoxia rat model

Treatment with mineralocorticoid receptor (MR) antagonists beginning at the outset of disease, or early thereafter, prevents pulmonary vascular remodeling in preclinical models of pulmonary arterial hypertension (PAH). However, the efficacy of MR blockade in established disease, a more clinically relevant condition, remains unknown. Therefore, we investigated the effectiveness of two MR antagonists, eplerenone (EPL) and spironolactone (SPL), after the development of severe right ventricular (RV) dysfunction in the rat SU5416-hypoxia (SuHx) PAH model. Cardiac magnetic resonance imaging (MRI) in SuHx rats at the end of week 5, before study treatment, confirmed features of established disease including reduced RV ejection fraction and RV hypertrophy, pronounced septal flattening with impaired left ventricular filling and reduced cardiac index. Five weeks of treatment with either EPL or SPL improved left ventricular filling and prevented the further decline in cardiac index compared with placebo. Interventricular septal displacement was reduced by EPL whereas SPL effects were similar, but not significant. Although MR antagonists did not significantly reduce pulmonary artery pressure or vessel remodeling in SuHx rats with established disease, animals with higher drug levels had lower pulmonary pressures. Consistent with effects on cardiac function, EPL treatment tended to suppress MR and proinflammatory gene induction in the RV. In conclusion, MR antagonist treatment led to modest, but consistent beneficial effects on interventricular dependence after the onset of significant RV dysfunction in the SuHx PAH model. These results suggest that measures of RV structure and/or function may be useful endpoints in clinical trials of MR antagonists in patients with PAH.

Right ventricular end-systolic remodeling index on cardiac magnetic resonance imaging: comparison with other functional markers in patients with chronic thromboembolic pulmonary hypertension

BACKGROUND

Cardiac magnetic resonance imaging (CMR) can provide important metrics of pulmonary hypertension. In the current study, we investigated whether the CMR-derived right ventricular end-systolic remodeling index (RVESRI) could be a metric in assessing the function and hemodynamics of chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

A total of 64 patients (45±14 years, 37 males), including 46 patients with CTEPH and 18 patients with chronic pulmonary thromboembolism (CTE), were retrospectively enrolled. All patients underwent right heart catheterization and CMR within 7 days. RVESRI, right ventricular eccentricity index, right ventricular end-diastolic and end-systolic volume index, right ventricular ejection fraction, right ventricular cardiac output, and strain were analyzed on cine images of CMR. Hemodynamic parameters including mean pulmonary arterial pressure, pulmonary vascular resistance, and cardiac output were obtained from right heart catheterization.

RESULTS

RVESRI of all patients was 1.50 (IQR, 1.26-1.90). Compared with CTE patients, RVESRI in patients with CTEPH was significantly increased (U=27.5, P<0.001). The interclass correlation coefficients of intra-observer reproducibility and inter-observer reproducibility for RVESRI measurement were 0.96 (95% CI, 0.93-0.97) and 0.99 (95% CI, 0.98-0.99), respectively. RVESRI positively correlated with right ventricular end-diastolic and end-systolic volume index and right ventricular global longitudinal strain (r=0.79, 0.83, 0.62, P<0.001), while it was negatively correlated with right ventricular ejection fraction (r=-0.64, P<0.001), right ventricular cardiac output (r=-0.50, P<0.001), and right ventricular eccentricity index (r=-0.81, P<0.001). RVESRI had a positive correlation with mean pulmonary arterial pressure (r=0.65, P<0.001) and pulmonary vascular resistance (r=0.69, P<0.001), while it was negatively correlated with cardiac output (r=-0.64, P<0.001). The receiver operating characteristic curve indicated that RVESRI >1.35 had a sensitivity of 97.8% and specificity of 83.3% in predicting mean pulmonary arterial pressure ≥25 mmHg, and its area under the curve (AUC) was 0.96±0.02. Meanwhile, the AUC of RVESRI was similar to RVEI (Z=1.635, P=0.102) and was more than the diameter of the main pulmonary artery (MPA) (Z=2.26, P=0.02) and the ratio of the MPA and ascending aorta diameter (MPA/AAo) (Z=3.826, P<0.001) in predicting mean pulmonary arterial pressure ≥25 mmHg.

CONCLUSIONS

RVESRI measured on CMR is a simple and reproducible metric in assessing right ventricular function and hemodynamics in CTEPH patients.

Cardiac MRI predictors of adverse outcomes in adults with a systemic right ventricle

Aims

Predicting risk in individuals with a systemic right ventricle (SRV) remains difficult. We assessed the value of cardiac MRI (CMR) for predicting death, heart transplantation (HT), or need for a ventricular assist device (VAD) in adults with D‐transposition of the great arteries (DTGA) post Mustard/Senning and in adults with congenitally corrected transposition of the great arteries (ccTGA) at two large academic centres.

Methods and results

Between December 1999 and November 2020, 158 adult patients with an SRV underwent CMR. Indexed right ventricular end‐diastolic volume (RVEDVI), indexed right ventricular end‐systolic volume (RVESVI), right ventricular ejection fraction (RVEF), and right ventricular mass (RV mass) were determined by a core laboratory. Receiver operating curves, area under the curve (AUC), and cut‐points maximizing sensitivity and specificity for the endpoint for each CMR parameter were calculated. Over a median of 8.5 years, 21 patients (13%) met a combined endpoint of HT referral, VAD, or death. Each CMR parameter was significantly associated with the endpoint in both cohorts. The AUCs for RVEDVI, RVESVI, RVEF, and RV mass to predict the endpoint were 0.93, 0.90, 0.73, and 0.84 for DTGA and 0.76, 0.74, 0.71, and 0.74 for ccTGA, respectively. Optimized cut‐points for RVEDVI were calculated for DTGA and ccTGA and were 132 and 126 mL/m², respectively. RVEDVI cut‐points were simplified to 130 mL/m² for survival analysis, which was significantly associated with survival in both cohorts.

Conclusions

Cardiac MRI parameters are associated with an increased risk of death, HT, or VAD in patients with an SRV and should be considered to facilitate risk stratification.

A Clinical Approach to Multimodality Imaging in Pulmonary Hypertension

Pulmonary hypertension (PH) is a clinical condition characterized by progressive elevations in mean pulmonary artery pressures and right ventricular dysfunction, associated with significant morbidity and mortality. For resting PH to develop, ~50-70% of the pulmonary vasculature must be affected, suggesting that even mild hemodynamic abnormalities are representative of advanced pulmonary vascular disease. The definitive diagnosis of PH is based upon hemodynamics measured by right heart catheterization; however this is an invasive and resource intense study. Early identification of pulmonary vascular disease offers the opportunity to improve outcomes by instituting therapies that slow, reverse, or potentially prevent this devastating disease. Multimodality imaging, including non-invasive modalities such as echocardiography, computed tomography, ventilation perfusion scans, and cardiac magnetic resonance imaging, has emerged as an integral tool for screening, classifying, prognosticating, and monitoring response to therapy in PH. Additionally, novel imaging modalities such as echocardiographic strain imaging, 3D echocardiography, dual energy CT, FDG-PET, and 4D flow MRI are actively being investigated to assess the severity of right ventricular dysfunction in PH. In this review, we will describe the utility and clinical application of multimodality imaging techniques across PH subtypes as it pertains to screening and monitoring of PH.