Effects of epoprostenol on right ventricular hypertrophy and dilatation in pulmonary hypertension

Establishing minimally important differences for cardiac MRI end-points in pulmonary arterial hypertension

BACKGROUND

Cardiac magnetic resonance (CMR) is the gold standard technique to assess biventricular volumes and function, and is increasingly being considered as an end-point in clinical studies. Currently, with the exception of right ventricular (RV) stroke volume and RV end-diastolic volume, there is only limited data on minimally important differences (MIDs) reported for CMR metrics. Our study aimed to identify MIDs for CMR metrics based on US Food and Drug Administration recommendations for a clinical outcome measure that should reflect how a patient "feels, functions or survives".

METHODS

Consecutive treatment-naïve patients with pulmonary arterial hypertension (PAH) between 2010 and 2022 who had two CMR scans (at baseline prior to treatment and 12 months following treatment) were identified from the ASPIRE registry. All patients were followed up for 1 additional year after the second scan. For both scans, cardiac measurements were obtained from a validated fully automated segmentation tool. The MID in CMR metrics was determined using two distribution-based (0.5sd and minimal detectable change) and two anchor-based (change difference and generalised linear model regression) methods benchmarked to how a patient "feels" (emPHasis-10 quality of life questionnaire), "functions" (incremental shuttle walk test) or "survives" for 1-year mortality to changes in CMR measurements.

RESULTS

254 patients with PAH were included (mean±sd age 53±16 years, 79% female and 66% categorised as intermediate risk based on the 2022 European Society of Cardiology/European Respiratory Society risk score). We identified a 5% absolute increase in RV ejection fraction and a 17 mL decrease in RV end-diastolic or end-systolic volumes as the MIDs for improvement. Conversely, a 5% decrease in RV ejection fraction and a 10 mL increase in RV volumes were associated with worsening.

CONCLUSIONS

This study establishes clinically relevant CMR MIDs for how a patient "feels, functions or survives" in response to PAH treatment. These findings provide further support for the use of CMR as a clinically relevant clinical outcome measure and will aid trial size calculations for studies using CMR.

The REPAIR Study: Effects of Macitentan on RV Structure and Function in Pulmonary Arterial Hypertension

OBJECTIVES

The REPAIR (Right vEntricular remodeling in Pulmonary ArterIal hypeRtension) study evaluated the effect of macitentan on right ventricular (RV) and hemodynamic outcomes in patients with pulmonary arterial hypertension (PAH), using cardiac magnetic resonance (CMR) and right heart catheterization (RHC).

BACKGROUND

RV failure is the primary cause of death in PAH. CMR is regarded as the most accurate noninvasive method for assessing RV function and remodeling and CMR measures of RV function and structure are strongly prognostic for survival in patients with PAH. Despite this, CMR is not routinely used in PAH clinical trials.

METHODS

REPAIR was a 52-week, open-label, single-arm, multicenter, phase 4 study evaluating the effect of macitentan 10 mg, with or without phosphodiesterase type-5 inhibition, on RV remodeling and function and cardiopulmonary hemodynamics. Primary endpoints were change from baseline to week 26 in RV stroke volume, determined by CMR; and pulmonary vascular resistance, determined by RHC. Efficacy measures were assessed for all patients with baseline and week 26 data for both primary endpoints.

RESULTS

At a prespecified interim analysis in 42 patients, both primary endpoints were met, enrollment was stopped, and the study was declared positive. At final analysis (n = 71), RV stroke volume increased by 12 mL (96% confidence level: 8.4-15.6 mL; P < 0.0001) and pulmonary vascular resistance decreased by 38% (99% confidence level: 31%-44%; P < 0.0001) at week 26. Significant positive changes were also observed in secondary and exploratory CMR (RV and left ventricular), hemodynamic, and functional endpoints at week 26. Improvements in CMR RV and left ventricular variables and functional parameters were maintained at week 52. Safety (n = 87) was consistent with previous clinical trials.

CONCLUSIONS

In the context of this study, macitentan treatment in patients with PAH resulted in significant and clinically-relevant improvements in RV function and structure and cardiopulmonary hemodynamics. At 52 weeks, improvements in RV function and structure were sustained. (REPAIR: Right vEntricular remodeling in Pulmonary ArterIal hypeRtension [REPAIR]; NCT02310672).

Allopurinol in Patients with Pulmonary Hypertension Associated with Chronic Lung Disease

Background

Oxidative stress (OS) has been implicated in the development of pulmonary hypertension (PH) and ventricular hypertrophy. Xanthine oxidase is a well-recognised source of reactive oxygen species, which lead to OS. The aim of this proof of concept study was to assess whether allopurinol (xanthine oxidase inhibitor) would reduce right ventricular mass (RVM) in patients with PH-associated chronic lung disease (PH-CLD).

Methods

We conducted a randomised, double-blind, parallel-group, placebo-controlled trial in patients with PH-CLD (93% COPD, 7% IPF) who were randomly assigned to receive allopurinol or placebo for 12 months. The primary outcome was the mean change in RVM, as assessed by cardiac magnetic resonance imaging (CMRI). Secondary outcomes included quality of life (QOL), spirometry and six-minute walk test (6MWT).

Results

Seventy-one patients were recruited: mean age 71 years, mean pulmonary arterial pressure 30 mm Hg, FEV₁ 60% and resting SpO₂ 96%. After 12 months, there was no significant difference in the change in RVM from baseline (allopurinol 1.85g vs placebo 0.97g with mean difference 0.88g, CI −4.77 to 3.01, p =0.7). There were also no significant changes in other cardiac parameters measured on MRI, in QOL, spirometry and 6MWT. Subgroup analysis showed that allopurinol significantly reduced RVM compared to placebo with -6.16g vs 0.75g and mean difference 6.92g (CI 1.14 to 12.69, p = 0.02) in COPD patients with more severe airflow limitation.

Conclusion

Allopurinol had no overall impact on patients with PH-CLD but had potential benefit in COPD patients with more severe airflow limitation.

Emerging role of cardiovascular magnetic resonance imaging in the management of pulmonary hypertension

Pulmonary hypertension (PH) is a clinical condition characterised by elevation of pulmonary arterial pressure (PAP) above normal range due to various aetiologies. While cardiac right-heart catheterisation (RHC) remains the gold standard and mandatory for establishing the diagnosis of PH, noninvasive imaging of the heart plays a central role in the diagnosis and management of all forms of PH. Although Doppler echocardiography (ECHO) can measure a range of haemodynamic and anatomical variables, it has limited utility for visualisation of the pulmonary artery and, oftentimes, the right ventricle. Cardiovascular magnetic resonance (CMR) provides comprehensive information about the anatomical and functional aspects of the pulmonary artery and right ventricle that are of prognostic significance for assessment of long-term outcomes in disease progression. CMR is suited for serial follow-up of patients with PH due to its noninvasive nature, high sensitivity to changes in anatomical and functional parameters, and high reproducibility. In recent years, there has been growing interest in the use of CMR derived parameters as surrogate endpoints for early-phase PH clinical trials. This review will discuss the role of CMR in the diagnosis and management of PH, including current applications and future developments, in comparison to other existing major imaging modalities.

Quantification of Cardiac Output with Phase Contrast Magnetic Resonance Imaging in Patients with Pulmonary Hypertension

Objective

The purpose of the study is to compare phase contrast (PC) imaging with invasive measurements of cardiac output (CO) in patients with pulmonary hypertension (PH).

Materials and Methods

We analyzed 81 cases with PH who underwent cardiac magnetic resonance imaging and right heart catheterization (RHC). Measurement of CO and stroke volume (SV) by cardiac magnetic resonance (CMR) was performed by PC imaging of the proximal aorta (Ao) and pulmonary artery (Pa) and by RHC using the Fick and thermodilution (TD) methods.

Results

There was good correlation in CO measurements between PC and RHC; however, there was better correlation with SV measurements; Fick-TD (r=0.85), PC-TD (Ao r=0.77, Pa r=0.79), and PC-Fick (Ao r = 0.73, Pa r = 0.78). Bland-Altman analysis of SV showed that Pa PC had slightly lower standard deviation than Ao PC; PC-Fick (Pa SD = 15.11 vs. Ao SD = 16.4 ml) and PC-TD (Pa SD = 16.99 ml vs. Ao SD = 17.4 ml) while Fick-TD had the lowest (SD = 14.4 ml). Compared to Fick, measurement of SV with Ao PC (‒4.12 ml) and Pa PC (0.22 ml) both had lower mean difference than TD (‒11.1 ml).

Conclusion

Non-invasive measurement of CO and SV using PC-CMR correlates well with invasive measurement using RHC. Our study showed that PC-CMR had high accuracy and precision when compared to Fick. Among all the modalities, PC-CMR contributed the least amount of variation in measurements.

EXPRESS: Preserving right ventricular function in patients with pulmonary arterial hypertension: single centre experience with a cardiac magnetic resonance imaging-guided treatment strategy

The feasibility and usefulness of routine cardiac magnetic resonance imaging (CMR) in the management of idiopathic pulmonary arterial hypertension (IPAH) is unknown. The aims of the study were: 1) to study whether a decrease in CMR‐derived right ventricular ejection fraction (RVEF) coincides with clinical deterioration; 2) to determine whether RVEF is responsive to early escalation of pulmonary arterial hypertension (PAH)‐specific therapy. This was a prospective study including 30 incident IPAH patients. Patients underwent right heart catheterization and CMR at regular follow‐up visits (baseline, four, eight, 12, 24 months; no right heart catheterization at eight months). New York Heart Association (NYHA) functional class II patients started with monotherapy (endothelin receptor antagonist or phosphodiesterase‐5‐inhibitor) and NYHA III patients with combination therapy (endothelin receptor antagonist plus phosphodiesterase‐5‐inhibitor). In the case of a deterioration in RVEF of more than 3% compared with the previous measurement, PAH‐specific therapy was added (i.e. treatment escalation). In 11 patients without signs of clinical deterioration, a greater than 3% decrease in RVEF occurred. After treatment escalation, RVEF significantly improved (average improvement of 7%, p = 0.009) whereas right ventricle volumes, N‐terminal pro‐brain natriuretic peptide and six‐minute walking distance remained stable. Clinical worsening did not occur after escalating therapy. Throughout the study, four patients presented with clinical worsening, despite a stable RVEF. Three of these four patients had a baseline RVEF <35%. In IPAH patients presenting with an early decrease in RVEF but otherwise stable disease, progressive right ventricle failure and subsequent clinical worsening did not occur when therapy was escalated. Nevertheless, clinical worsening did occur in patients with a low baseline RVEF.

Protective effect of Xin-Ji-Er-Kang on cardiovascular remodeling in high salt-induced hypertensive mice

The aim of the present study was to investigate the effects of Xin-Ji-Er-Kang (XJEK) on high salt-induced hypertensive mice. Mice with high-salt diet-induced hypertension were divided into four groups: Control (standard diet alone for 8 weeks), model (diet containing 8% NaCl for 8 weeks and intragastric administration of distilled water for the last 4 weeks), XJEK + high-salt-treated (diet containing 8% NaCl for 8 weeks and intragastric administration of XJEK for the last 4 weeks) and irbesartan + high-salt-treated (diet containing 8% NaCl for 8 weeks with intragastric administration of irbesartan for the last 4 weeks). The hemodynamic index and cardiac pathological changes in the hypertensive mice were then examined. An aortic ring apparatus was used to detect acetylcholine-dependent endothelium relaxation function. Colorimetric analysis was applied to determine serum nitric oxide (NO), superoxide dismutase activity and malondialdehyde content; ELISA was employed to measure brain natriuretic peptide, serum angiotensin II (Ang II), endothelin-1 content and aldosterone; and immunohistochemistry was used to detect the expression of endothelial nitric oxide synthase (eNOS), interleukin (IL)-1β, IL-10 and tumor necrosis factor (TNF)-α in cardiac tissues. XJEK improved the heart systolic and diastolic function, ameliorated hemodynamic parameters and cardiovascular remodeling indices, blunted the cardiac pathological changes and improved endothelial dysfunction (ED) via boosting eNOS activity, promoting NO bioavailability and decreasing serum Ang II content. Furthermore, treatment with XJEK inhibited the increase of IL-1β and TNF-α expression and the decrease of IL-10 expression in cardiac tissues, and ameliorated oxidative stress status. Therefore, XJEK exerted protective effects against high salt-induced hypertension and cardiovascular remodeling in mice via improving ED, restoring pro- and anti-inflammatory factor balance and decreasing oxidative stress.

Pulmonary Artery Stiffness by Cardiac Magnetic Resonance Imaging Predicts Major Adverse Cardiovascular Events in patients with Chronic Obstructive Pulmonary Disease

In this prospective pilot study, we aimed to evaluate the ability of cardiac magnetic resonance imaging (CMR) parameters of right ventricular function and pulmonary artery stiffness to identify pulmonary hypertension (PH), predict major adverse cardiovascular events (MACEs) in patients with secondary PH due to chronic obstructive pulmonary disease (COPD), and to estimate a prospective sample size necessary for a reliable power of the study. Thirty consecutive patients with COPD and suspected secondary PH were assessed by clinical examination, the six minute walk test, echocardiography, right heart catheterization and CMR, and followed-up for a mean period of 16 months to identify MACEs (cardiac death, ventricular tachyarrhythmia, and heart failure). Among CMR parameters of pulmonary artery stiffness, pulse wave velocity (PWV) yielded the best sensitivity (93.5%) and specificity (92.8%) for identifying PH, as diagnosed by cardiac catheterization. Moreover, PWV proved to be a valuable predictor of MACEs (HR = 4.75, 95% CI 1.00 to 22.59, p = 0.03). In conclusion, PWV by phase-contrast CMR can accurately identify PH in patients with COPD and may help stratify prognosis.

NOX4 expression and distal arteriolar remodeling correlate with pulmonary hypertension in COPD

Background

Pulmonary hypertension (PH) in chronic obstructive pulmonary disease (COPD) is suggested as the consequence of emphysematous destruction of vascular bed and hypoxia of pulmonary microenvironment, mechanisms underpinning its pathogenesis however remain elusive. The dysregulated expression of nicotinamide adenine dinucleotide phosphate (NADPH)-oxidases and superoxide generation by pulmonary vasculatures have significant implications in the hypoxia-induced PH.

Methods

In this study, the involvement of NADPH oxidase subunit 4 (NOX4) in pulmonary arteriolar remodeling of PH in COPD was investigated by ascertaining the morphological alteration of pulmonary arteries and pulmonary blood flow using cardiac magnetic resonance imaging (cMRI), and the expression and correlation of NOX4 with pulmonary vascular remodeling and pulmonary functions in COPD lungs.

Results

Results demonstrated that an augmented expression of NOX4 was correlated with the increased volume of pulmonary vascular wall in COPD lung. While the volume of distal pulmonary arteries was inversely correlated with pulmonary functions, despite it was positively associated with the main pulmonary artery distensibility, right ventricular myocardial mass end-systolic and right ventricular myocardial mass end-diastolic in COPD. In addition, an increased malondialdehyde and a decreased superoxide dismutase were observed in sera of COPD patients. Mechanistically, the abundance of NOX4 and production of reactive oxygen species (ROS) in pulmonary artery smooth muscle cells could be dynamically induced by transforming growth factor-beta (TGF-β), which in turn led pulmonary arteriolar remodeling in COPD lungs.

Conclusion

These results suggest that the NOX4-derived ROS production may play a key role in the development of PH in COPD by promoting distal pulmonary vascular remodeling.

Risk Assessment in Pulmonary Arterial Hypertension Patients: The Long and Short of it

Pulmonary arterial hypertension (PAH) is a chronic and rapidly progressive disease that is characterized by extensive narrowing of the pulmonary vasculature, leading to increases in pulmonary vascular resistance, subsequent right ventricular dysfunction, and eventual death. There are currently multiple approved drugs—developed as single or combination therapies in the last few years—that have improved outcome and functionality in PAH. However, despite improvement in short-term survival with these new effective therapies, PAH remains an incurable disease with a median survival of 7 years (Figure 1).1 This chronic disease state may be characterized by morbid events such as hospitalizations that herald rapid disease progression and account for a significant disease burden (Figure 2).23 Physician ability to predict PAH disease progression is critical for determining optimal care of patients. Accurate risk assessment allows clinicians to determine the patient's prognosis, identify treatment goals, and monitor disease progression and the patient's response to treatment. Risk assessment for PAH patients should include a range of clinical, hemodynamic, and exercise parameters, performed in a serial fashion over the treatment course. Patient risk stratification can also help physicians better allocate treatment resources in settings where they are scarce. If widely adopted, risk prediction can enhance the consistency of treatment approaches across PAH practitioners and improve the timeliness of referral for lung transplantation. Hence, along with advancing PAH treatment options, comprehensive risk prediction is essential to make individualized treatment decisions in the current treatment era.

Several tools are currently available for assessing risk in PAH (Figure 3). These include the 2015 European Society of Cardiology/European Respiratory Society pulmonary hypertension guidelines' risk variables,4 the French registry equation,5 the National Institutes of Health risk equation,6 or a risk score such as the one derived from the Registry to Evaluate Early And Long-term PAH Disease Management.1 These registries and evaluations of clinical trial sets have provided important insights into the importance of both modifiable (eg, 6-minute walk distance, functional class, brain natriuretic peptide, and nonmodifiable (eg, age, gender, PAH etiology) risk factors that predict survival. The following review explores commonly cited risk factors, both modifiable and nonmodifiable, and their implications for patient outcomes.

Bosentan-based, treat-to-target therapy in patients with pulmonary arterial hypertension: results from the COMPASS-3 study

The phase 4 COMPASS-3 study evaluated whether a singular endpoint produces clinically meaningful outcomes in patients with pulmonary arterial hypertension (PAH). The relationship between cardiac magnetic resonance imaging (cMRI)-derived parameters and right heart catheterization (RHC) measurements was also examined. In COMPASS-3 (ClinicalTrials.gov NCT00433329), 100 patients with PAH received bosentan monotherapy for 16 weeks. Patients continued monotherapy if their 6-min walk distance (6MWD) was ≥380 m, or otherwise received add-on sildenafil for an additional 12 weeks. 6MWD, RHC, and cMRI were performed at baseline, week 16, and week 28 (6MWD and cMRI). Baseline median 6MWD was 274 m and 82% of patients had WHO Functional Class III/IV. At week 16, 17% (n = 16) of remaining patients achieved the 6MWD threshold and 78 (83%) did not. In the intention-to-treat population, median 6MWD increased significantly relative to baseline (week 16 = 308 m; week 28 = 327 m; P < 0.001). At week 28, 9/16 (monotherapy) and 15/76 (20%; add-on sildenafil) patients met the target threshold. Baseline cMRI-derived and RHC-derived parameters showed moderate-to-strong correlations (e.g. right to left ventricular end-diastolic ratio [RVEDV:LVEDV] correlated strongly with pulmonary vascular resistance [r = +0.729, P < 0.0001]). cMRI-derived parameters predicted clinical worsening/decline (e.g. week 16 RVEDV:LVDEV [P = 0.0172]). Time to clinical worsening/decline did not differ between patients based on 6MWD threshold achievement. No unexpected safety events were reported. A substantial proportion of patients failed to achieve the goal of 380 m, regardless of treatment. Several cMRI parameters predicted clinical worsening/decline and its non-invasive nature further supports its use in future clinical trials.

Upfront combination therapy reduces right ventricular volumes in pulmonary arterial hypertension

In pulmonary arterial hypertension (PAH), upfront combination therapy is associated with better clinical outcomes and a greater reduction in N-terminal pro-brain natriuretic peptide (NT-proBNP) than monotherapy. NT-proBNP levels reflect right ventricular (RV) wall stress, which increases when the right ventricle dilates. This study explored the impact of upfront combination therapy on RV volumes compared with monotherapy in PAH patients.This retrospective study involved 80 incident PAH patients (New York Heart Association class II and III) who were treated with upfront combination therapy (n=35) (i.e. endothelin receptor antagonists (ERAs) plus phosphodiesterase-5-inhibitors (PDE5Is)) or monotherapy (n=45) (i.e. either ERAs or PDE5Is). All patients underwent right-sided heart catheterisation and cardiac magnetic resonance imaging at baseline and after 1-year follow-up.Combination therapy resulted in more significant reductions in pulmonary vascular resistance and pulmonary pressures than monotherapy. NT-proBNP was decreased by ∼77% in the combination therapy group compared with a ∼51% reduction after monotherapy (p<0.001). RV volumes and calculated RV wall stress improved after combination therapy (both p<0.001) but remained unchanged after monotherapy (both p=NS). RV ejection fraction improved more in the combination therapy group than in the monotherapy group (p<0.001).In PAH patients, upfront combination therapy was associated with improved RV volumes.

Reliable and developmentally appropriate study end points are needed to achieve drug development for treatment of pediatric pulmonary arterial hypertension

OBJECTIVE

To identify suitable end points and surrogates for pediatric pulmonary arterial hypertension (PAH) as the lack of developmentally appropriate end point and clinical trials contribute to the unmet medical need.

STUDY DESIGN

Reviewed the efficacy end points and surrogates for all trials (1995 to 2013) that were submitted to the Food and Drug Administration (FDA) to support the approval of PAH therapy and conducted literature search.

RESULTS

An increase in the 6 min walking distance (6MWD) was used as a primary end point in 8/9 adult PAH trials. This end point is not suitable for infants and young children because of performance limitations and lack of control data. One adult PAH trial used time to the first morbidity or mortality event as a primary end point, which could potentially be used in pediatric PAH trials. In the sildenafil pediatric PAH trial, the change in pulmonary vascular resistance index or mean pulmonary artery pressure was used as a surrogate for the 6MWD to assess exercise capacity. However, two deaths and three severe adverse events during the catheterizations made this an unacceptably high-risk surrogate. The INOmax persistent pulmonary hypertension of the newborn trial used a reduction in initiation of extracorporeal membrane oxygenation treatment as a primary end point, which is not feasible for other pediatric PAH trials. A Literature review revealed none of the existing noninvasive markers are fully validated as surrogates to assess PAH efficacy and long-term safety.

CONCLUSIONS

For pediatric PAH trials, clinical end points are acceptable, and novel validated surrogates would be helpful. FDA seeks collaboration with academia, industry and parents to develop other suitable and possibly more efficient efficacy end points to facilitate pediatric PAH drug development.

MR and CT Imaging for the Evaluation of Pulmonary Hypertension

Imaging plays a central role in the diagnosis and management of all forms of pulmonary hypertension (PH). Although Doppler echocardiography is essential for the evaluation of PH, its ability to optimally evaluate the right ventricle and pulmonary vasculature is limited by its 2-dimensional planar capabilities. Magnetic resonance and computed tomography are capable of determining the etiology and pathophysiology of PH, and can be very useful in the management of these patients. Exciting new techniques such as right ventricle tissue characterization with T1 mapping, 4-dimensional flow of the right ventricle and pulmonary arteries, and computed tomography lung perfusion imaging are paving the way for a new era of imaging in PH. These imaging modalities complement echocardiography and invasive hemodynamic testing and may be useful as surrogate endpoints for early phase PH clinical trials. Here we discuss the role of magnetic resonance imaging and computed tomography in the diagnosis and management of PH, including current uses and novel research applications, and we discuss the role of value-based imaging in PH.

Prognostic value of TAPSE after therapy optimisation in patients with pulmonary arterial hypertension is independent of the haemodynamic effects of therapy

Objective

To evaluate the prognostic significance of right ventricular function assessed by echocardiography after start or escalation of targeted therapy in patients with pulmonary arterial hypertension.

Methods

Study design: longitudinal study. Setting: tertiary referral centre for pulmonary hypertension. Patients: 81 consecutive patients with pulmonary arterial hypertension (33 naive and 48 prevalent). Interventions: right heart catheterisation and echocardiography performed prior to starting or escalating targeted therapy and repeated in 55 patients after 4–12 months of therapy. Main outcome measure: survival after follow-up examinations.

Results

11 patients died and 7 were lost to follow-up during the first year; 8 patients underwent first follow-up evaluation beyond 1 year. 55 patients were re-evaluated after therapy; during the subsequent follow-up period of 25 months, 9 patients died, 7 worsened from WHO I/II to III/IV and 15 remained in WHO III/IV despite therapy. A baseline tricuspid annular plane systolic excursion (TAPSE) ≥15 mm was associated with a lower risk of death (HR=0.32; 95% CI 0.12 to 0.83, p=0.012). Attaining a TAPSE≥15 mm after therapy was associated with a significantly lower risk of death or clinical worsening (HR=0.2; 95% CI 0.1 to 0.6, p=0.002) and a lower risk of death which approached statistical significance (HR=0.3; 95% CI 0.2 to 1.1, p=0.075). Per cent changes in TAPSE were loosely related to changes in pulmonary vascular resistances after therapy (R=0.37).

Conclusions

In patients with pulmonary arterial hypertension, the evaluation of right ventricular function by TAPSE after targeted therapy is useful to predict subsequent prognosis, regardless of the haemodynamic effects of therapy.

Oestradiol metabolism and androgen receptor genotypes are associated with right ventricular function

Sex hormones are linked to right ventricular (RV) function, but the relationship between genetic variation in these pathways and RV function is unknown.We performed a cross-sectional study of 2761 genotyped adults without cardiovascular disease. The relationships between RV measures and single nucleotide polymorphisms (SNPs) in 10 candidate genes were assessed. Urinary oestradiol (E2) metabolites produced by cytochrome P4501B1 (CYP1B1) and serum testosterone were measured in women and men respectively.In African-American (AA) women, the CYP1B1 SNP rs162561 was associated with RV ejection fraction (RVEF), such that each copy of the A allele was associated with a 2.0% increase in RVEF. Haplotype analysis revealed associations with RVEF in AA (global p<7.2×10(-6)) and white (global p=0.05) women. In white subjects, higher E2 metabolite levels were associated with significantly higher RVEF. In men, androgen receptors SNPs (rs1337080; rs5918764) were significantly associated with all RV measures and modified the relationship between testosterone and RVEF.Genetic variation in E2 metabolism and androgen signalling was associated with RV morphology in a sex-specific manner. The CYP1B1 SNP identified is in tight linkage disequilibrium with SNPs associated with pulmonary hypertension and oncogenesis, suggesting these pathways may underpin sexual dimorphism in RV failure.

Biomarkers for pediatric pulmonary arterial hypertension: challenges and recommendations

Pediatric pulmonary arterial hypertension (PAH) is an uncommon disease that can occur in neonates, infants, and children, and is associated with high morbidity and mortality. Despite advances in treatment strategies over the last two decades, the underlying structural and functional changes to the pulmonary arterial circulation are progressive and lead eventually to right heart failure. The management of PAH in children is complex due not only to the developmental aspects but also because most evidence-based practices derive from adult PAH studies. As such, the pediatric clinician would be greatly aided by specific characteristics (biomarkers) objectively measured in children with PAH to determine appropriate clinical management. This review highlights the current state of biomarkers in pediatric PAH and looks forward to potential biomarkers, and makes several recommendations for their use and interpretation.

Quantitative magnetic resonance imaging of pulmonary hypertension: a practical approach to the current state of the art

Pulmonary hypertension is a condition of varied etiology, commonly associated with poor clinical outcome. Patients are categorized on the basis of pathophysiological, clinical, radiologic, and therapeutic similarities. Pulmonary arterial hypertension (PAH) is often diagnosed late in its disease course, with outcome dependent on etiology, disease severity, and response to treatment. Recent advances in quantitative magnetic resonance imaging (MRI) allow for better initial characterization and measurement of the morphologic and flow-related changes that accompany the response of the heart-lung axis to prolonged elevation of pulmonary arterial pressure and resistance and provide a reproducible, comprehensive, and noninvasive means of assessing the course of the disease and response to treatment. Typical features of PAH occur primarily as a result of increased pulmonary vascular resistance and the resultant increased right ventricular (RV) afterload. Several MRI-derived diagnostic markers have emerged, such as ventricular mass index, interventricular septal configuration, and average pulmonary artery velocity, with diagnostic accuracy similar to that of Doppler echocardiography. Furthermore, prognostic markers have been identified with independent predictive value for identification of treatment failure. Such markers include large RV end-diastolic volume index, low left ventricular end-diastolic volume index, low RV ejection fraction, and relative area change of the pulmonary trunk. MRI is ideally suited for longitudinal follow-up of patients with PAH because of its noninvasive nature and high reproducibility and is advantageous over other biomarkers in the study of PAH because of its sensitivity to change in morphologic, functional, and flow-related parameters. Further study on the role of MRI image based biomarkers in the clinical environment is warranted.

Prognostic value of echocardiographic changes in patients with pulmonary arterial hypertension receiving parenteral prostacyclin therapy

BACKGROUND

It is unknown whether the echocardiographic changes observed after treatment of patients with pulmonary arterial hypertension have prognostic value.

METHODS

Subjects with pulmonary arterial hypertension, confirmed by right heart catheterization, who underwent Doppler echocardiography before (baseline) and after 1 year of treatment (follow-up) with parenteral prostacyclin analogues were retrospectively identified. Echocardiographic parameters were measured offline by two investigators.

RESULTS

A total of 48 patients were included (mean age, 45 ± 14 years; 83% women). Compared with baseline, follow-up echocardiography showed reductions in right atrial area (mean percentage change, 12 ± 25%; P < .001), right ventricular (RV) basal and middle cavity dimensions (mean percentage change, 8.5 ± 14% [P < .001] and 6.8 ± 17% [P = .005], respectively), and peak tricuspid regurgitant velocity (mean percentage change, 10 ± 14%; P < .001). Tricuspid annular plane systolic excursion (mean percentage change, 36 ± 43%; P < .001) and RV outflow tract time-velocity integral (mean percentage change, 48 ± 66%; P < .001) increased. During a median follow-up period of 52.5 months (interquartile range, 20.5-80 months), 18 patients (37.5%) died, mostly (n = 15 [83%]) from progression of pulmonary arterial hypertension. The changes in RV end-diastolic area (hazard ratio [HR per 10% decrease, 0.73; 95% confidence interval [CI], 0.57-0.93), tricuspid valve regurgitation velocity (HR per 10 cm/sec decrease, 0.58; 95% CI, 0.37-0.89), RV outflow tract velocity-time integral (HR per 10% increase, 0.90; 95% CI, 0.83-0.98), and subjective RV function (HR per 1 unit of improvement [e.g., from moderate to mild], 0.55; 95% CI, 0.31-0.96) were associated with overall mortality.

CONCLUSIONS

Echocardiographic parameters that estimate RV systolic pressure and assess RV morphology and function improve after 1 year of prostacyclin analogue treatment, and the degree of change has prognostic implications.

Increased levels of plasma CXC-Chemokine Ligand 10, 12 and 16 are associated with right ventricular function in patients with idiopathic pulmonary arterial hypertension

OBJECTIVE

To investigate plasma levels of CXC-Chemokine Ligand 10 (CXCL10), CXC-Chemokine Ligand 12 (CXCL12) and CXC-Chemokine Ligand 16 (CXCL16) in patients with idiopathic pulmonary arterial hypertension (IPAH).

METHODS

Plasma levels of biomarkers were measured by enzyme-linked immunosorbent assay in 61 patients with IPAH and 20 healthy volunteers.

RESULTS

Plasma CXCL10, CXCL12 and CXCL16 concentrations were increased significantly in IPAH patients compared with controls, and significantly correlated with N-terminal pro-brain natriuretic peptide, tricuspid annulus plane systolic excursion and right ventricular ejection fraction.

CONCLUSIONS

Increased levels of CXCL10, CXCL12 and CXCL16 are associated with right ventricular dysfunction in patients with IPAH.

Assessment of right ventricular responses to therapy in pulmonary hypertension

Irrespective of its cause, pulmonary hypertension (PH) leads to an increase in pulmonary vascular resistance (PVR). Failing adaption of the right ventricle (RV) to the increased afterload is the main cause of death in PH patients and therefore monitoring RV function during treatment is essential. However, consensus on the optimal method for serial assessment of RV function is lacking and therefore the major clinical trials on PH-specific therapies have not provided clear answers with respect to the response of the RV to treatment. This short review will give an overview of the most important load-dependent and load-independent parameters for assessing RV response to therapy in PH patients.

Biomarkers for pediatric pulmonary arterial hypertension - a call to collaborate

Therapeutic approaches in pediatric pulmonary arterial hypertension (PAH) are based primarily on clinician experience, in contrast to the evidence-based approach in adults with pulmonary hypertension. There is a clear and present need for non-invasive and objective biomarkers to guide the accurate diagnosis, treatment, and prognosis of this disease in children. The multifaceted spectrum of disease, clinical presentation, and association with other diseases makes this a formidable challenge. However, as more progress is being made in the understanding and management of adult PAH, the potential to apply this knowledge to children has never been greater. This review explores the state of the art with regard to non-invasive biomarkers in PAH, with an eye toward those adult PAH biomarkers potentially suitable for application in pediatric PAH.

A systematic review of the diagnostic accuracy of cardiovascular magnetic resonance for pulmonary hypertension

BACKGROUND

The diagnostic accuracy of cardiovascular magnetic resonance (CMR) for pulmonary hypertension (PH) compared with right heart catheterization were assessed. The purpose of this systematic review was to comprehensively evaluate the diagnostic accuracy of CMR in evaluating PH.

METHODS

Published literature was obtained from PUBMED, Web of Knowledge, Cochrane library, Embase, Biosis Preview, China National Knowledge Infrastructure, and Chongqing VIP databases, and all studies were inclusive until December 2012. Studies relevant to PH and its imaging in CMR and right heart catheterization were included if correlation coefficient was elucidated clearly. Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) score was used to assess the quality of studies. Sensitivity and specificity were pooled separately and compared with overall accuracy measures: diagnostic odds ratio and symmetric summary receiver operating characteristic.

RESULTS

Sixteen studies were included in the systematic review. Of all the studies, the most widely used index was ventricular mass index (VMI) of CMR. We performed a meta-analysis for VMI among 429 patients in 5 individual studies, which showed a modest diagnostic accuracy of VMI for PH with a summary sensitivity and specificity of 84% (95% confidence interval, 79%-87%) and 82% (95% confidence interval, 73%-89%), respectively. In addition, the summary positive likelihood ratio was 4.894, indicating that VMI of CMR allows a modest ability to distinguish PH patients from healthy subjects with a cutoff point of 0.45 using functional and structural measures.

CONCLUSIONS

This systematic review and meta-analysis indicates that VMI seems to have a moderate sensitivity and specificity for detection of PH. The application values of other parameters still need further investigation.

Assessment of operability of patients with pulmonary arterial hypertension associated with congenital heart disease

Pulmonary arterial hypertension (PAH) is a common complication of congenital heart disease, and is now predominantly among patients with uncorrected left-to-right shunts. A growing population is characterized by persistent or recurrent PAH after surgical or interventional correction of left-to-right shunts; the latter having a worse prognosis than other forms of PAH associated with congenital heart disease. New treatments for PAH have been shown to be effective in improving PAH exercise capacity and hemodynamics, raising the hope for making previously inoperable congenital heart defects operable and shifting the framework for the assessment of operability. This review focuses on current methods for assessing operability in PAH associated with congenital heart disease, and the possibility of "treat-and-repair" vs. "repair-and-treat" strategies for patients with inoperable or borderline PAH.

Sample size and cost analysis for pulmonary arterial hypertension drug trials using various imaging modalities to assess right ventricular size and function end points

BACKGROUND

Placebo-controlled trials for pulmonary arterial hypertension are no longer acceptable because new therapies must show clinically significant effects on top of standard treatment. The purpose of this study was to estimate sample sizes and imaging costs for the planning of a hypothetical pulmonary arterial hypertension drug trial using imaging to detect changes in right ventricular size and function in response to combined therapy.

METHODS AND RESULTS

Same-day cardiovascular MR (CMR) and 2-dimensional (2D) and 3D transthoracic echocardiography (2DTTE and 3DTTE) were performed in 22 patients with pulmonary arterial hypertension (54±13 years of age) twice, 6 months apart. Short-axis CMR cines and full-volume 3DTTE data sets of the right ventricle were used to measure end-diastolic volume and ejection fraction. Fractional area change was obtained from 2DTTE. Sample size calculations used a 2-sample t test model incorporating differences between baseline and 6-month measurements. Cost estimates were made using the Medicare fee schedule. No significant differences were noted between baseline and follow-up measurements. Large SDs reflected variable progression of disease in individual patients on standard therapy and measurement variability. These sources of variability resulted in intertechnique differences in sample sizes: to detect a change of 5% to 15% in 3DTTE-derived right ventricular ejection fraction and fractional area change or change of 15 to 30 mL in 3DTTE right ventricular end-diastolic volume; sample sizes were 2× to 2.5× those required by CMR. As a result, the total cost of a trial using complete TTE was greater than CMR, which was greater than limited TTE.

CONCLUSIONS

Because of lower measurement variability, CMR is more cost saving in pulmonary arterial hypertension drug trials than echocardiography, unless limited TTE is used.

Integrated pharmacokinetics and pharmacodynamics of epoprostenol in healthy subjects

AIM

The aim of the study was to report the first thorough characterization of the pharmacokinetics (PK) and pharmacodynamics (PD) of epoprostenol in an integrated manner.

METHOD

Twenty healthy male subjects received two formulations of i.v. epoprostenol, in a crossover design, in sequential infusions of 2, 4, 6 and 8 ng kg(-1)  min(-1) for 2 h each. A sensitive assay was developed which allowed accurate PK characterization of epoprostenol via analysis of the concentration-time profiles of its two primary metabolites, 6-keto-prostacyclin F(1α) and 6,15-diketo-13,14-dihydro-prostacyclin F(1α) . PD parameters included cardiac output (CO), cardiac index (CIn) and heart rate (HR).

RESULTS

The pharmacokinetics of epoprostenol deviated slightly from dose-proportionality, probably due to a food effect. After infusion of the two formulations of epoprostenol, the t(1/2) values expressed as geometric mean (95% confidence interval) were 0.25 h (0.14, 0.46) and 0.22 h (0.13, 0.38) for 6-keto-prostacyclin F(1α) , and 0.32 h (0.22, 0.45) and 0.34 h (0.26, 0.46) for 6,15-diketo-13,14-dihydro-prostacyclin F(1α) . A single compartment infusion model with first order elimination adequately described the PK of 6-keto-prostacyclin F(1α) . This model also characterized the food effect. Stepwise infusions with epoprostenol resulted in a progressive increase in CO, CIn and HR.

CONCLUSION

Of the two metabolites analyzed, the appearance of 6-keto-prostacyclin F(1α) in plasma was more closely associated with the haemodynamic effects of i.v. epoprostenol. PK and PD profiles showed that CIn relates proportionally and linearly to the plasma concentrations of 6-keto-prostacyclin F(1α) . These results suggest that 6-keto-prostacyclin F(1α) is a suitable surrogate marker of plasma concentrations of epoprostenol.

Comparative pharmacokinetic, pharmacodynamic, safety, and tolerability profiles of 3 different formulations of epoprostenol sodium for injection in healthy men

BACKGROUND

Epoprostenol sodium for injection is approved for the treatment of severe cases of primary pulmonary arterial hypertension. Currently, there are 3 approved formulations of this drug containing the same active ingredient (epoprostenol sodium) but differing with regard to excipients. When compared with epoprostenol sodium formulated with glycine-mannitol (epoprostenol GM), 2 new formulations of epoprostenol sodium, one formulated with arginine-mannitol (epoprostenol AM) and one formulated with arginine-sucrose (epoprostenol AS), have improved stability after reconstitution and dilution. The biocomparability of epoprostenol AM and epoprostenol GM, with regard to pharmacokinetic (PK), pharmacodynamic (PD), safety, and tolerability profiles, has been shown previously.

OBJECTIVE

This study compared PK, PD, safety, and tolerability profiles of the 3 different formulations of epoprostenol sodium for injection.

METHODS

This was a prospective, single-center, open-label, 2-period, 2-treatment, randomized, crossover, ascending dose study in 2 parts. Twenty healthy men in part 1 and 20 different individuals in part 2 received epoprostenol AM and epoprostenol AS and epoprostenol GM and epoprostenol AS, respectively, in a crossover fashion, as sequential IV infusions of 2, 4, 6, and 8 ng/kg/min for 2 hours each. In each part, the PK profile of epoprostenol was characterized via analysis of the concentration-time profiles of its 2 primary metabolites: 6-keto-prostacyclin F1α and 6,15-diketo-13,14-dihydro-prostacyclin F1α. The effect of the formulations was assessed using the 90% CI of the geometric mean ratio calculated for the exposure PK parameters. The PD variables cardiac output, cardiac index, and heart rate were assessed using echocardiography. Adverse events were recorded through the study.

RESULTS

The plasma concentration versus time curves of epoprostenol AM and epoprostenol AS in part 1 and epoprostenol GM and epoprostenol AS in part 2 were similar in shape and almost superimposable. For each study part, the 90% CIs of ratios of geometric means for AUC0-∞ of the assessed epoprostenol formulations were within the range for bioequivalence (0.8-1.25). The increases in cardiac output, cardiac index, and heart rate resulting from infusion with epoprostenol sodium were comparable between all formulations, with maximum values attained after 8 hours. Almost all study participants reported at least one treatment-emergent adverse event, the most common being headache, which was reported in 80% to 85% of study participants.

CONCLUSIONS

Overall, the PK, PD, safety, and tolerability profiles of the 3 formulations of epoprostenol sodium for injection are comparable and meet the criteria of bioequivalence. Australian New Zealand Clinical Trials Registry identifier: ACTRN12612001086853.

Cardiomyocyte-specific overexpression of HEXIM1 prevents right ventricular hypertrophy in hypoxia-induced pulmonary hypertension in mice

Right ventricular hypertrophy (RVH) and right ventricular (RV) contractile dysfunction are major determinants of prognosis in pulmonary arterial hypertension (PAH) and PAH remains a severe disease. Recently, direct interruption of left ventricular hypertrophy has been suggested to decrease the risk of left-sided heart failure. Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) is a negative regulator of positive transcription elongation factor b (P-TEFb), which activates RNA polymerase II (RNAPII)-dependent transcription and whose activation is strongly associated with left ventricular hypertrophy. We hypothesized that during the progression of PAH, increased P-TEFb activity might also play a role in RVH, and that HEXIM1 might have a preventive role against such process. We revealed that, in the mouse heart, HEXIM1 is highly expressed in the early postnatal period and its expression is gradually decreased, and that prostaglandin I(2), a therapeutic drug for PAH, increases HEXIM1 levels in cardiomyocytes. These results suggest that HEXIM1 might possess negative effect on cardiomyocyte growth and take part in cardiomyocyte regulation in RV. Using adenovirus-mediated gene delivery to cultured rat cardiomyocytes, we revealed that overexpression of HEXIM1 prevents endothelin-1-induced phosphorylation of RNAPII, cardiomyocyte hypertrophy, and mRNA expression of hypertrophic genes, whereas a HEXIM1 mutant lacking central basic region, which diminishes P-TEFb-suppressing activity, could not. Moreover, we created cardiomyocyte-specific HEXIM1 transgenic mice and revealed that HEXIM1 ameliorates RVH and prevents RV dilatation in hypoxia-induced PAH model. Taken together, these findings indicate that cardiomyocyte-specific overexpression of HEXIM1 inhibits progression to RVH under chronic hypoxia, most possibly via inhibition of P-TEFb-mediated enlargement of cardiomyocytes. We conclude that P-TEFb/HEXIM1-dependent transcriptional regulation may play a pathophysiological role in RVH and be a novel therapeutic target for mitigating RVH in PAH.

Evaluation of right ventricular remodeling using cardiac magnetic resonance imaging in co-existent chronic obstructive pulmonary disease and obstructive sleep apnea

Untreated chronic obstructive pulmonary disease (COPD) co-existing with obstructive sleep apnea (OSA), also known as overlap syndrome, has higher cardiovascular mortality than COPD alone but its underlying mechanism remains unclear. We hypothesize that the presence of overlap syndrome is associated with more extensive right ventricular (RV) remodeling compared to patients with COPD alone. Adult COPD patients (GOLD stage 2 or higher) with at least 10 pack-years of smoking history were included. Overnight laboratory-based polysomnography was performed to test for OSA. Subjects with an apnea-hypopnea index (AHI) >10/h were classified as having overlap syndrome (n = 7), else classified as having COPD-only (n = 11). A cardiac MRI was performed to assess right and left cardiac chambers sizes, ventricular masses, and cine function. RV mass index (RVMI) was markedly higher in the overlap group than the COPD-only group (19 ± 6 versus 11 ± 6; p = 0.02). Overlap syndrome subjects had a reduced RV remodeling index (defined as the ratio between RVMI and RV end-diastolic volume index) compared to the COPD-only group (0.27 ± 0.06 versus 0.18 ± 0.08; p = 0.02). In the overlap syndrome subjects, the extent of RV remodeling was associated with severity of oxygen desaturation (R(2) = 0.65, p = 0.03). Our pilot results suggest that untreated overlap syndrome may cause more extensive RV remodeling than COPD alone.

The renin-angiotensin system and right ventricular structure and function: The MESA-Right Ventricle Study

The pulmonary vasculature is an important site of renin-angiotensin metabolism. While angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (collectively AIABs) have a role in left ventricular (LV) disease, the impact of AIABs on right ventricular (RV) function is unknown. AIAB use was determined by medication inventory during the Multi-Ethnic Study of Atherosclerosis baseline examination. RV measures were obtained via cardiac magnetic resonance imaging. The relationship between AIAB use and RV measures was assessed using multivariable linear regression, stratified by race/ethnicity, and adjusted for multiple covariates. AIAB use was associated with lower RV mass (-0.7 g, 95% confidence interval [CI] -1.3 to -0.1, P=0.03) in African Americans (N=1012) after adjustment for multiple covariates including LV mass. Among Caucasians (N=1591), AIAB use was associated with larger RV end-diastolic volume (3.7 mL, 95% CI 0.7-6.8, P=0.02) after adjustment for LV volume. No significant associations were seen between AIAB use and other RV measures or in Hispanic or Chinese American participants. AIAB use was associated with RV morphology in a race-specific and LV-independent manner, suggesting the renin-angiotensin system may play a unique role in RV structure and function. The use of AIABs in those with RV dysfunction warrants further study.

Cardiac magnetic resonance imaging: what can it add to our knowledge of the right ventricle in pulmonary arterial hypertension?

Pulmonary arterial hypertension (PAH) is a disease of the pulmonary vasculature characterized by vasoconstriction and vascular remodeling leading to a progressive increase in pulmonary vascular resistance (PVR). It is becoming increasingly recognized that it is the response of the right ventricle (RV) to the increased afterload resulting from this increase in PVR that is the most important determinant of patient outcome. A range of hemodynamic, structural, and functional measures associated with the RV have been found to have prognostic importance in PAH and, therefore, have potential value as parameters for the evaluation and follow-up of patients. If such measures are to be used clinically, there is a need for simple, reproducible, accurate, easy-to-use, and noninvasive methods to assess them. Cardiac magnetic resonance imaging (CMRI) is regarded as the "gold standard" method for assessment of the RV, the complex structure of which makes accurate assessment by 2-dimensional methods, such as echocardiography, challenging. However, the majority of data concerning the use of CMRI in PAH have come from studies evaluating a variety of different measures and using different techniques and protocols, and there is a clear need for the development of standardized methodology if CMRI is to be established in the routine assessment of patients with PAH. Should such standards be developed, it seems likely that CMRI will become an important method for the noninvasive assessment and monitoring of patients with PAH.

Today's and tomorrow's imaging and circulating biomarkers for pulmonary arterial hypertension

The pathobiology of pulmonary arterial hypertension (PAH) involves a remodeling process in distal pulmonary arteries, as well as vasoconstriction and in situ thrombosis, leading to an increase in pulmonary vascular resistance, right heart failure and death. Its etiology may be idiopathic, but PAH is also frequently associated with underlying conditions such as connective tissue diseases. During the past decade, more than welcome novel therapies have been developed and are in development, including those increasingly targeting the remodeling process. These therapeutic options modestly increase the patients' long-term survival, now approaching 60% at 5 years. However, non-invasive tools for confirming PAH diagnosis, and assessing disease severity and response to therapy, are tragically lacking and would help to select the best treatment. After exclusion of other causes of pulmonary hypertension, a final diagnosis still relies on right heart catheterization, an invasive technique which cannot be repeated as often as an optimal follow-up might require. Similarly, other techniques and biomarkers used for assessing disease severity and response to treatment generally lack specificity and have significant limitations. In this review, imaging as well as current and future circulating biomarkers for diagnosis, prognosis, and follow-up are discussed.

Selective serotonin reuptake inhibitor use is associated with right ventricular structure and function: the MESA-right ventricle study

PURPOSE

Serotonin and the serotonin transporter have been implicated in the development of pulmonary hypertension (PH). Selective serotonin reuptake inhibitors (SSRIs) may have a role in PH treatment, but the effects of SSRI use on right ventricular (RV) structure and function are unknown. We hypothesized that SSRI use would be associated with RV morphology in a large cohort without cardiovascular disease (N = 4114).

METHODS

SSRI use was determined by medication inventory during the Multi-Ethnic Study of Atherosclerosis baseline examination. RV measures were assessed via cardiac magnetic resonance imaging. The cross-sectional relationship between SSRI use and each RV measure was assessed using multivariable linear regression; analyses for RV mass and end-diastolic volume (RVEDV) were stratified by sex.

RESULTS

After adjustment for multiple covariates including depression and left ventricular measures, SSRI use was associated with larger RV stroke volume (RVSV) (2.75 mL, 95% confidence interval [CI] 0.48-5.02 mL, p = 0.02). Among men only, SSRI use was associated with greater RV mass (1.08 g, 95% CI 0.19-1.97 g, p = 0.02) and larger RVEDV (7.71 mL, 95% 3.02-12.40 mL, p = 0.001). SSRI use may have been associated with larger RVEDV among women and larger RV end-systolic volume in both sexes.

CONCLUSIONS

SSRI use was associated with higher RVSV in cardiovascular disease-free individuals and, among men, greater RV mass and larger RVEDV. The effects of SSRI use in patients with (or at risk for) RV dysfunction and the role of sex in modifying this relationship warrant further study.

Cardiovascular magnetic resonance in pulmonary hypertension

Pulmonary hypertension represents a group of conditions characterized by higher than normal pulmonary artery pressures. Despite improved treatments, outcomes in many instances remain poor. In recent years, there has been growing interest in the use of cardiovascular magnetic resonance (CMR) in patients with pulmonary hypertension. This technique offers certain advantages over other imaging modalities since it is well suited to the assessment of the right ventricle and the proximal pulmonary arteries. Reflecting the relatively sparse evidence supporting its use, CMR is not routinely recommended for patients with pulmonary hypertension. However, it is particularly useful in patient with pulmonary arterial hypertension associated with congenital heart disease. Furthermore, it has proven informative in a number of ways; illustrating how right ventricular remodeling is favorably reversed by drug therapies and providing explicit confirmation of the importance of the right ventricle to clinical outcome. This review will discuss these aspects and practical considerations before speculating on future applications.

Diagnosis and treatment of pulmonary hypertension: an update

Over the last five years, knowledge in the field of pulmonary hypertension has grown consistently and significantly. On the basis of various clinical studies showing the usefulness of new diagnostic tools, as well as the efficacy of new medications and drug combinations, new diagnostic and treatment algorithms have been developed. Likewise, in order to simplify the clinical management of patients, the classification of pulmonary hypertension has been changed in an attempt to group the various forms of pulmonary hypertension in which the diagnostic and therapeutic approaches are similar. The objective of this review was to discuss these modifications, based on the 2005 Brazilian guidelines for the management of pulmonary hypertension, emphasizing what has been added to the international guidelines.

Prolonged beneficial effect of bosentan treatment and 4-year survival rates in adult patients with pulmonary arterial hypertension associated with congenital heart disease

Pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD) due to systemic to pulmonary shunting is associated with a high risk of morbidity and mortality. In this study we evaluated 4 years treatment effect of bosentan on exercise capacity and quality of life and survival rates in 64 adult patients with PAH associated with CHD, including patients with Down syndrome (DS). All patients were evaluated at baseline and during follow-up with laboratory tests, 6-minute walk test, quality of life questionnaires, and Doppler echocardiography. In total, 13 patients (20%) died during 4-years of follow-up; 4 patients with DS and 9 patients without DS. Mean follow-up of all patients treated with bosentan was 3.5 ± 1.2 year. We analyzed treatment efficacy separately within patients without DS (n=34) and patients with DS (n=30). Mean 6-minute walking distance (6 MWD) in patients without DS significantly increased at 6 months from 417 ± 108 to 458 ± 104 m (+41 m; p=0.002) and significant improvement continued to exist during at least 2.5 years of follow-up (p=0.003). Moreover, stroke volume increased significantly (p=0.02). In the patients with DS, 6-MWD, stroke volume and quality of life remained stable during treatment. In this study we demonstrate a prolonged beneficial effect of bosentan treatment on exercise capacity, stroke volume and quality of life in patients without DS. However the mortality rate of 20% of patients after 4 years of follow-up remains high.

Assessment of pulmonary hypertension what CT and MRI can provide

RATIONALES AND OBJECTIVES

Pulmonary hypertension (PH) is a life-threatening condition, characterized by elevated pulmonary arterial pressure, which is confirmed based on invasive right heart catheterization (RHC). Noninvasive examinations may support diagnosis of PH before proceeding to RHC and play an important role in management and treatment of the disease. Although echocardiography is considered a standard tool in diagnosis, recent advances have made computed tomography (CT) and magnetic resonance (MR) imaging promising tools, which may provide morphologic and functional information. In this article, we review image-based assessment of PH with a focus on CT and MR imaging.

CONCLUSIONS

CT may provide useful morphologic information for depicting PH and seeking for underlying diseases. With the accumulated technological advancement, CT and MRI may provide practical tools for not only morphologic but also functional assessment of patients with PH.

Right ventricular dysfunction and failure in chronic pressure overload

Right ventricular (RV) dysfunction is the main cause of death in pulmonary arterial hypertension (PAH). Our understanding of the pathophysiology of RV dysfunction is limited but improving. Methods to better diagnose RV dysfunction earlier and treatments specifically designed to minimize or reverse the remodeling process are likely to improve outcomes. We review the current understanding of RV dysfunction in chronic pressure overload and introduce some novel insights based on recent investigations into pathophysiology, diagnosis, and treatment.

Sex hormones are associated with right ventricular structure and function: The MESA-right ventricle study

RATIONALE

Sex hormones have effects on the left ventricle, but hormonal influences on the right ventricle (RV) are unknown.

OBJECTIVES

We hypothesized that sex hormones would be associated with RV morphology in a large cohort free of cardiovascular disease.

METHODS

Sex hormones were measured by immunoassay and RV ejection fraction (RVEF), stroke volume (RVSV), mass, end-diastolic volume, and end-systolic volume (RVESV) were measured by cardiac magnetic resonance imaging in 1,957 men and 1,738 postmenopausal women. The relationship between each hormone and RV parameter was assessed by multivariate linear regression.

MEASUREMENTS AND MAIN RESULTS

Higher estradiol levels were associated with higher RVEF (β per 1 ln[nmol/L], 0.88; 95% confidence interval [CI], 0.32 to 1.43; P = 0.002) and lower RVESV (β per 1 ln[nmol/L], -0.87; 95% CI, -1.67 to -0.08; P = 0.03) in women using hormone therapy. In men, higher bioavailable testosterone levels were associated with higher RVSV (β per 1 ln[nmol/L], 1.97; 95% CI, 0.20 to 3.73; P = 0.03) and greater RV mass and volumes (P ≤ 0.01). Higher dehydroepiandrosterone levels were associated with higher RVSV (β per 1 ln[nmol/L], 1.37; 95% CI, 0.15 to 2.59; P = 0.03) and greater RV mass (β per 1 ln[nmol/L], 0.25; 95% CI, 0.00 to 0.49; P = 0.05) and volumes (P ≤ 0.001) in women.

CONCLUSIONS

Higher estradiol levels were associated with better RV systolic function in women using hormone therapy. Higher levels of androgens were associated with greater RV mass and volumes in both sexes.

Long-term outcomes in pulmonary arterial hypertension in the first-line epoprostenol or first-line bosentan era

BACKGROUND

The aim of this study was to describe the long-term outcomes in idiopathic pulmonary arterial hypertension (IPAH) treated with first-line bosentan or intravenous (IV) epoprostenol, and additional therapy as needed.

METHODS

In a single-center, retrospective, longitudinal cohort, data on right heart catheterization, 6-minute walk distance (6MWD), disease progression and mortality were collected. Outcomes were assessed in first-line bosentan and first-line epoprostenol patients. To reduce selection bias due to differences between groups, two independent analyses were performed. First, a comparison was made of World Health Organization (WHO) Functional Class (FC) III patients. Second, to control for disease severity, a matched-pairs analysis was performed, with matching according to baseline cardiac output and exercise capacity and irrespective of FC at baseline.

RESULTS

Thirty-seven IPAH patients initiated first-line bosentan treatment and 37 first-line IV epoprostenol. Twenty-nine of the bosentan patients and 16 of the IV epoprostenol patients were in WHO FC III; demographic profiles were similar, although hemodynamic measurements and 6MWD suggested more severe disease in the IV epoprostenol group at treatment initiation. At 1 and 3 years, median change in 6MWD for patients initiating bosentan was +54 m (95% confidence interval: -3 to 76) and +71 m (-123 to 116), respectively, and +92 m (17 to 128) and +142 m (-6 to 242) for those on IV epoprostenol. Absence of disease progression of WHO FC III at 1 and 3 years was 72% and 45% with bosentan and 75% and 44% with IV epoprostenol, respectively. Survival at 1 and 3 years was 93% and 89% with bosentan and 94% and 75% with IV epoprostenol, respectively. Results were confirmed in matched-pairs analysis of 16 bosentan and 16 IV epoprostenol patients with similar disease severity.

CONCLUSIONS

First-line epoprostenol treatment may lead to greater improvement in exercise capacity than first-line bosentan. However, these greater exercise improvements did not translate into longer time to disease progression or survival.

Assessment of right ventricular systolic function: comparison between cardiac magnetic resonance derived ejection fraction and pulsed-wave tissue Doppler imaging of the tricuspid annulus

BACKGROUND

Systolic right ventricular (RV) function is an important predictor in the course of various congenital and acquired heart diseases. Its practical determination by echocardiography remains challenging. We compared routine assessment of lateral tricuspid annular systolic motion velocity (TV(lat), cm/s) using pulsed-wave tissue Doppler imaging from the apical 4-chamber view with cardiac magnetic resonance (CMR) as reference method.

METHODS AND RESULTS

254 individuals (43 ± 18 years) underwent both CMR (contiguous short axis slices; retrogated cine steady state free precession technique; manual contour tracing) and echocardiography within 2 ± 2 months. Seventy-five had coronary artery disease, 87 congenital heart disease, 17 dilated cardiomyopathy, 15 pulmonary artery hypertension, and 47 normal findings. RV ejection fraction (EF) by CMR was 51 ± 12% (range 17-78%). There was a linear correlation between RVEF and TV(lat) (r=0.60; p<0.0001). A TV(lat) cut-off of 12 cm/s identified patients with normal EF (≥50%) with 81% sensitivity and 68% specificity, and a threshold of TV(lat) <9 cm/s identified patients with severely reduced RVEF (<30%) with 82% sensitivity and 86% specificity.

CONCLUSIONS

Systolic long-axis velocity measurements of the lateral tricuspid annulus allow a reliable assessment of RVEF in clinical routine. A threshold of TV(lat)<9 cm/s identifies patients with severely reduced RVEF (<30%) with high sensitivity and specificity.