Survival with first-line bosentan in patients with primary pulmonary hypertension

A Lifelike guided journey through the pathophysiology of pulmonary hypertension-from measured metabolites to the mechanism of action of drugs

Introduction

Pulmonary hypertension (PH) is a pathological condition that affects approximately 1% of the population. The prognosis for many patients is poor, even after treatment. Our knowledge about the pathophysiological mechanisms that cause or are involved in the progression of PH is incomplete. Additionally, the mechanism of action of many drugs used to treat pulmonary hypertension, including sotatercept, requires elucidation.

Methods

Using our graph-powered knowledge mining software Lifelike in combination with a very small patient metabolite data set, we demonstrate how we derive detailed mechanistic hypotheses on the mechanisms of PH pathophysiology and clinical drugs.

Results

In PH patients, the concentration of hypoxanthine, 12(S)-HETE, glutamic acid, and sphingosine 1 phosphate is significantly higher, while the concentration of L-arginine and L-histidine is lower than in healthy controls. Using the graph-based data analysis, gene ontology, and semantic association capabilities of Lifelike, led us to connect the differentially expressed metabolites with G-protein signaling and SRC. Then, we associated SRC with IL6 signaling. Subsequently, we found associations that connect SRC, and IL6 to activin and BMP signaling. Lastly, we analyzed the mechanisms of action of several existing and novel pharmacological treatments for PH. Lifelike elucidated the interplay between G-protein, IL6, activin, and BMP signaling. Those pathways regulate hallmark pathophysiological processes of PH, including vasoconstriction, endothelial barrier function, cell proliferation, and apoptosis.

Discussion

The results highlight the importance of SRC, ERK1, AKT, and MLC activity in PH. The molecular pathways affected by existing and novel treatments for PH also converge on these molecules. Importantly, sotatercept affects SRC, ERK1, AKT, and MLC simultaneously. The present study shows the power of mining knowledge graphs using Lifelike's diverse set of data analytics functionalities for developing knowledge-driven hypotheses on PH pathophysiological and drug mechanisms and their interactions. We believe that Lifelike and our presented approach will be valuable for future mechanistic studies of PH, other diseases, and drugs.

Stress hyperglycemia is associated with poor outcome in critically ill patients with pulmonary hypertension

Background and objective

Stress hyperglycemia is common in critically ill patients and is associated with poor prognosis. Whether this association exists in pulmonary hypertension (PH) patients is unknown. The present cohort study investigated the association of stress hyperglycemia with 90-day all-cause mortality in intensive care unit (ICU) patients with PH.

Methods

Data of the study population were extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. A new index, the ratio of admission glucose to HbA1c (GAR), was used to evaluate stress hyperglycemia. The study population was divided into groups according to GAR quartiles (Q1-Q4). The outcome of interest was all-cause mortality within 90 days, which was considered a short-term prognosis.

Result

A total of 53,569 patients were screened. Ultimately, 414 PH patients were enrolled; 44.2% were male, and 23.2% were admitted to the cardiac ICU. As the GAR increased from Q2 to Q4, the groups had lower creatinine levels, longer ICU stays, and a higher proportion of renal disease. After adjusting for confounding factors such as demographics, vital signs, and comorbidities, an elevated GAR was associated with an increased risk of 90-day mortality.

Conclusion

Stress hyperglycemia assessed by the GAR was associated with increased 90-day mortality in ICU patients with PH.

Severity of precapillary pulmonary hypertension: Predictive factor

BACKGROUND AND OBJECTIVES

Patients with pulmonary arterial hypertension (PAH) require risk assessments for prognosis and appropriate therapy. These assessments need to be improved by incorporating clinical and laboratory data such as the analysis of the right ventricle. We aim to establish echocardiographic morphometric data of the right ventricle and its relationship with the left ventricle, to estimate the hemodynamic severity of precapillary pulmonary hypertension (PHprecapillary).

METHODS

This cohort, prospective, observational, and cross-sectional study included 41 consecutive patients with PHprecapillary using echocardiographic study and cardiac catheterization.

RESULTS

Patients' mean age was 44.0±16.4 years, and 37 were women (90.2%). Idiopathic PAH was diagnosed in 18 patients (43.9%). The World Health Organization/New York Association functional class was III or IV in 31 patients (75.6%). The ratio of the right to left ventricles (RV/LV) echocardiographic diastolic diameters was associated with pulmonary arterial pressures in cardiac catheterization, with the best cutoff per receiver operating characteristic curve being 0.8 for systolic pressure (sensitivity 90.0%, specificity 78.3%, area under the curve [AUC] 0.882) and mean pressure (sensitivity 60.0%, specificity 95.7%, AUC 0.823). Spearman's correlation (R) of RV/LV echocardiographic ratio and the hemodynamic variables was significant for systolic pressure (R = 0.7015, p < 0.0001), mean pressure (R = 0.6332, p < 0.0001), transpulmonary pressure gradient (R = 0.6524, p < 0.0001), pulmonary vascular resistance (R = 0.6076, p = 0.0021), and pulmonary vascular resistance index (R = 0.6229, p = 0.0014).

CONCLUSION

The ratio of RV/LV echocardiographic diastolic diameters contribute to the estimates the hemodynamic severity of precapillary pulmonary hypertension. The best cutoff for this assessment was RV/LV of 0.8.

Efficacy and safety of macitentan for pulmonary hypertension: A meta-analysis

INTRODUCTION

Our purpose of this study is to evaluate the effect and safety of macitentan in the treatment of pulmonary hypertension (PH).

METHODS

We retrieved the safety and efficacy of macitentan treatment for PH using PubMed, the Cochrane Library, EMBASE databases and clinicaltrials.gov. The Cochrane Risk of Bias Tool was used for literature screening and quality assessment. Data analysis was conducted using RevMan 5.4.1 and Stata/SE 15.1 software. Results are presented as standardization mean differences (SMDs) and odds ratio (OR).

RESULTS

Meta-analysis of seven randomized controlled trial (RCT) studies and four non-RCT studies with 2769 patients was included, involving 723 in the macitentan group and 599 in the placebo group. The results of the study showed that macitentan had effectively decreased pulmonary vascular resistance (PVR) (SMD = -0.53, 95% CI: -0.77--0.29, p < 0.05), cardiac index (CI) (SMD = 0.60, 95% CI: 0.37-0.83, p < 0.05) and N-terminal pro-brain natriuretic peptide (NT-proBNP) (SMD = -0.22, 95% CI: -0.40--0.03, p < 0.05). Furthermore, macitentan also significantly reduced PVR (SMD = -0.58, 95% CI: -0.80--0.35, p < 0.05), 6-min walk distance (6WMD) (SMD = 0.33, 95% CI: 0.15-0.50, p < 0.05), CI (SMD = 0.48, 95% CI: 0.28-0.69, p < 0.05), mean pulmonary arterial pressure (mPAP) (SMD = -0.43, 95% CI: -0.64--0.23, p < 0.05) and NT-proBNP (SMD = -0.55, 95% CI: -1.07--0.03, p < 0.05) between baseline and follow-up. The adverse reactions to macitentan were mild, with headache, anaemia and bronchitis. Other efficacy and safety outcomes did not reach statistical differences.

CONCLUSION

Macitentan therapy for PH is effective and safe. The effectiveness on PVR, mPAP, mean right atrial pressure (mRAP), mortality and other indicators still needs to be further confirmed.

Pulmonary Circulation Under Pressure: Pathophysiological and Therapeutic Implications of BK Channel

The large-conductance Ca2+-activated K+ (BK) channel is widely expressed in the pulmonary blood vessels and plays a significant role in regulating pulmonary vascular tonus. It opens under membrane depolarization, increased intracellular Ca+2 concentration, and chronic hypoxia, resulting in massive K+ efflux, membrane hyperpolarization, decreased L-type Ca+2 channel opening, and smooth muscle relaxation. Several reports have demonstrated an association between BK channel dysfunction and pulmonary hypertension (PH) development. Decreased BK channel subunit expression and impaired regulation by paracrine hormones result in decreased BK channel opening, increased pulmonary vascular resistance, and pulmonary arterial pressure being the cornerstone of PH. The resulting right ventricular pressure overload ultimately leads to ventricular remodeling and failure. Therefore, it is unsurprising that the BK channel has arisen as a potential target for treating PH. Recently, a series of selective, synthetic BK channel agonists have proven effective in attenuating the pathophysiological progression of PH without adverse effects in animal models.

Right Ventricular Energy Failure Predicts Mortality in Patients With Pulmonary Hypertension

Right ventricular (RV) failure has a significant adverse impact on pulmonary hypertension (PH) prognosis. None of the currently used parameters directly assess whether RV fails to provide enough energy output to propel the blood through diseased pulmonary vascular system. Furthermore, most of the current parameters are affected by the volume status of the patient. We aimed to explore whether RV energy failure has a predictive power for mortality on top of the established prognostic risk parameters in patients with PH. We screened 723 cases from our database. A total of 3 sets of binary regression analyses were executed to determine the hazard ratios (HRs) of RV energy failure for 5-year mortality in clinical, echocardiographic, and hemodynamic context, using adjustment variables chosen according to previous studies. The final study population encompassed 549 cases. A total of 77 patients died during the 5-year follow-up (14%). RV energy failure was observed in 146 of 549 patients (26.6%). In the univariate model, RV energy failure strongly associated with increased long-term mortality (HR 4.25, 95% confidence interval [CI] 2.58 to 7.00, p <0.001). It also emerged as a significant predictor of long-term mortality in clinical and hemodynamic multivariate models (HR 2.59, 95% CI 1.43 to 4.67, p = 0.002 and HR 2.05, 95% CI 1.15 to 3.63, p = 0.015, respectively). In conclusion, our study indicates that the presence of RV energy failure independently predicts long-term mortality in PH.

Treatment of nonarteritic anterior ischemic optic neuropathy with an endothelin antagonist: ENDOTHELION (ENDOTHELin antagonist receptor in Ischemic Optic Neuropathy)—a multicentre randomised controlled trial protocol

Background

Nonarteritic anterior ischemic optic neuropathy (NAAION) is a major cause of blindness in individuals over 50 years of age, with no available effective treatment. The oral dual endothelin receptor antagonist, bosentan, increases retinal optic nerve head blood flow in healthy humans and glaucoma patients. The objective of this trial is to assess the efficacy of bosentan administered at the acute stage in improving outcomes in NAAION patients.

Methods

ENDOTHELION (ENDOTHELin antagonist receptor in Ischemic Optic Neuropathy) is a phase III, interventional, prospective, multicentre, placebo-controlled randomised double-blind clinical trial. The primary outcome is change in the visual field mean deviation (MD) at 3 months (Humphrey 30-2 SITA standard programme). Secondary outcomes include MD and visual acuity changes up to 24 months, changes in peripapillary retinal nerve fibre and macular ganglion cell layer thickness in the affected eye, as measured by optical coherence tomography, rate of NAAION bilateralisation at 2 years, and quality-of-life. Patients over 50 years of age presenting with typical NAAION of recent onset (less than 21 days) are randomly assigned to either 125 mg oral bosentan or placebo, twice a day, during 8 weeks. Besides visits during the treatment phase, patients attend follow-up visits at 2, 3, 6, 12 and 24 months. The inclusion of patients began in August 2015 at five French University hospital ophthalmology departments and two specialised ophthalmology centres. It is planned to include 86 patients in this trial. To date we have included 72 patients and 49 have completed the full follow-up process.

Discussion

An endothelin receptor antagonist is a potential approach to improving the anatomical and functional prognosis of patients with NAAION. This multicentre double-blind randomised controlled trial is an opportunity to assess (1) the effect of bosentan on the structure and function of the optic nerve in NAAION, at 3 months, (2) the effect of bosentan on the bilateralisation rate at 24 months and (3) the tolerance profile of bosentan in this population.

Trial registration

ClinicalTrials.gov NCT02377271. Registered on March 3, 2015.

Prospective clinical assessment of patients with pulmonary arterial hypertension switched from bosentan to macitentan (POTENT)

Even though pulmonary arterial hypertension (PAH) remains an incurable disease, the combination of PAH‐specific therapies allowed evolving from symptom‐based strategies to others aiming to move patients to low‐risk conditions. Endothelin‐1 (ET‐1) receptor antagonists emerged as specific‐PAH drugs that can be used in combination with other specific therapies. This work aimed to perform a prospective clinical assessment of patients with PAH that switched from bosentan to macitentan (POTENT), due to inadequate response. POTENT is a prospective, open‐label, single‐arm, uncontrolled study including PAH patients from our ongoing SAUDIPH registry. It enrolled 50 PAH patients divided as follows: idiopathic/heritable pulmonary arterial hypertension (I/HPAH); n = 24; PAH associated with congenital heart disease, n = 19; PAH associated with connective tissue diseases, n = 5; and pulmonary veno‐occlusive disease and/or pulmonary capillary haemangiomatosis (PVOD/PCH), n = 2. At baseline, most patients were in World Health Organization Functional Class (WHO FC) II/III (52.0%). After switching to macitentan, patients were more likely to be in WHO FC I/II (78%) and 22% of the overall cohort moved to a lower risk condition, with three low risk stratification parameters. Mean 6‐min walking distance increased about 34 m after 12 months, with a significant mean change over time (12.63 ± 11.69 at month 3 vs. 40.75 ± 12.57 at month 12, p = 0.002). Most haemodynamic parameters decreased over time, with corresponding negative mean changes (p < 0.001). The safety of macitentan was confirmed by the absence of anaemia and liver injury; clinical worsening was observed only in a small group of patients. In general, macitentan might be a valid alternative to bosentan in PAH stable patients on combination therapy with insufficient clinical response, and presenting intermediate and high‐risk parameters. We anticipate that studying this strategy in PAH subgroups would further clarify its potential and limitations.

Riociguat for Sarcoidosis-Associated Pulmonary Hypertension: Results of a 1-Year Double-Blind, Placebo-Controlled Trial

BACKGROUND

Riociguat is effective in delaying the time to clinical worsening (TCW) in patients with groups 1 and 4 pulmonary hypertension.

RESEARCH QUESTION

Is riociguat more effective than placebo in prolonging TCW in sarcoidosis-associated pulmonary hypertension (SAPH)?

STUDY DESIGN AND METHODS

This was a double-blind placebo-controlled trial. Patients with SAPH confirmed by right heart catheterization were randomized 1:1 to riociguat or placebo. Patients underwent 6-min walk distance (6MWD) and spirometry testing every 8 weeks. The primary end point was TCW, which was defined by the time to the first of the following: (1) all-cause mortality, (2) need for hospitalization because of worsening cardiopulmonary status attributable to progression of disease, (3) > 50 m decrease in the 6MWD test, or (4) worsening of World Health Organization functional class.

RESULTS

A total of 16 patients were randomized to riociguat (n = 8) or placebo (n = 8). No difference was found in pulmonary artery mean, pulmonary vascular resistance, initial 6MWD, or FVC between the two groups. Five of eight patients who received placebo met TCW criteria, whereas none of the patients who received riociguat experienced a qualifying event. By log-rank analysis, patients who received riociguat were in the study for a significantly longer period (χ ² = 6.259; P = .0124). The 6MWD decreased in the placebo group (median, -55.9 m; range, -176.8 to 60 m), but rose in the riociguat group (median, +42.7 m; range, -7.5 to +91.4 m; P = .0149), with a placebo-corrected difference of 94 m (P < .01). Four of eight patients who received riociguat, but only 1 of 8 patients who received placebo, showed a > 30-m improvement in 6MWD (P > .05). No significant adverse events associated with riociguat occurred.

INTERPRETATION

Over the 1 year of the study, riociguat was effective in preventing clinical worsening and improving exercise capacity in patients with SAPH.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02625558; URL: www.clinicaltrials.gov.

Comparative assessment of efficacy and safety of ambrisentan and bosentan in patients with pulmonary arterial hypertension: A meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Two endothelin receptor antagonists, ambrisentan and bosentan, have been demonstrated to be effective individually compared with placebo in the treatment of patients with pulmonary arterial hypertension (PAH). This network meta-analysis compared the efficacy and safety of ambrisentan and bosentan in patients with PAH.

METHODS

Clinical trials were identified from the Cochrane Central Register of Controlled Trials (CENTRAL/CCTR), EMBASE and PubMed databases. Weighted mean differences (MD) with 95% confidence intervals (CI) were calculated for continuous outcomes (6-min walk distance [6MWD] and Borg dyspnoea index [BDI]). Hazard ratio (HR) was calculated for binary outcomes, including clinical worsening, discontinuation due to adverse events (AEs) and liver dysfunction. Surface under cumulative ranking curve (SUCRA) was used to rank the treatments in each index.

RESULTS

Five clinical trials from four published studies (total patients: n = 920) were included. Ambrisentan and bosentan showed no significant difference in 6MWD (MD: -1.32; 95% CI: -27.87, 25.31, SUCRA score: ambrisentan 0.73, bosentan 0.77), BDI (MD: -0.16; 95% CI: -0.98, 0.65, SUCRA score: ambrisentan 0.83, bosentan 0.66), clinical worsening (HR: 0.99; 95% CI: 0.33, 2.94, SUCRA score: ambrisentan 0.75, bosentan 0.74) and discontinuation due to AEs (HR: 0.84; 95% CI: 0.11, 5.86, SUCRA score: ambrisentan 0.47, bosentan 0.57). However, ambrisentan was significantly better than bosentan with respect to abnormal liver function (HR: 23.18; 95% CI: 2.24, 377.20, SUCRA score: ambrisentan 0.99, bosentan 0.02).

WHAT IS NEW AND CONCLUSION

The results of this network meta-analysis suggest that ambrisentan was similar to bosentan in efficacy, while it exhibited better tolerability with respect to abnormal liver function in comparison with bosentan, in patients with PAH.

Soluble ST2 and mixed venous oxygen saturation for prediction of mortality in patients with pulmonary hypertension

Background

Although soluble suppression of tumorigenicity-2 (sST2) has been identified as a clinical biomarker for pulmonary hypertension (PH) by previous studies, the implication of sST2 combined with hemodynamic parameters in PH has not been well studied. This study aimed to evaluate the relationship between sST2 and hemodynamic parameters and to evaluate the predictive value of sST2 for mortality in patients with PH.

Methods

One hundred eighty-four incident patients with PH and 14 healthy controls were retrospectively enrolled by Shanghai Pulmonary Hospital for this retrospective study. After all patients underwent right heart catheterization, blood samples were collected and serum sST2 concentration was assessed by the Presage™ ST2 assay. Kaplan-Meier curve and Cox regression analyses were used to predict survival and the association between survival and different factors such as sST2, SvO₂.

Results

During a follow-up of 44.9 (IQR 28.5–64.4) months, 65 patients died. The median concentration of sST2 in PH patients was 33.1 ng/mL, which is higher than that in control group (23.1 ng/mL, P=0.005). Furthermore, for PH group, the level of sST2 was higher in non-survivors than that in survivors. Cox regression analyses demonstrated that sST2 and SvO₂ were independent risk factors for survival. In Kaplan-Meier curve analyses, elevated sST2 level and reduced SvO₂ predicted a poor outcome for patients with PH.

Conclusions

Higher sST2 was independently associated with increased mortality, as well as lower SvO₂ in patients with PH. Especially, the combination of higher sST2 and lower SvO₂ had the strongest predictive value of mortality in patients with PH.

Efficacy and Safety of Long-Term Oral Bosentan in Different Types of Pulmonary Arterial Hypertension: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis was conducted to identify if long-term bosentan is an effective and safe treatment for pulmonary arterial hypertension (PAH) regardless of type, including idiopathic PAH (IPAH), and PAH associated with congenital heart disease (APAH-CHD), connective tissue disease (APAH-CTD), and human immunodeficiency virus (APAH-HIV).

METHODS

All relevant observations were systematically searched by two independent investigators and obtained from three databases, including PubMed, EMBASE and the Cochrane Library, from the inception of each database to February 2020. Currently, long-term administration was defined as no less than 12 months. A random-effects or fixed-effects model was selected according to outcomes of the heterogeneity test for meta-analysis, where standardized mean difference (SMD) with 95% confidence intervals (CIs) was used for continuous outcomes, in addition to the estimated effect (ES; 95% CI) for the synthesized survival rate. Furthermore, subgroup analysis was applied to analyze the differences of efficacy and survivals in each type of PAH cohort.

RESULTS

Fifteen studies including a total of 659 subjects undergoing oral bosentan administration for at least 12 months were pooled in this quantitative review. Meta-analysis and subgroup analysis indicated that significant clinical benefits existed, including an improved 6-min walk distance (6MWD) and functional class (FC), in patients with APAH-CHD (6MWD: SMD 0.72, 95% CI 0.52-0.93, p < 0.0001; functional benefits: 50.4%, 95% CI 43.7-57.1%), APAH-HIV (6MWD: SMD 0.83, 95% CI 0.36-1.30, p = 0.001; functional benefits: 80.4%), and IPAH (SMD 0.54, 95% CI 0.28-0.80, p < 0.0001; functional benefits: 61.4%, 95% CI 54.2-68.5%), but a non-significant change in APAH-CTD (6MWD: SMD 0.18, 95% CI - 0.60 to 0.95, p = 0.656; functional benefits: 27.5%). Furthermore, among the hemodynamic parameters, long-term bosentan led to a significant decrease in mean pulmonary artery pressure (SMD - 0.86, p < 0.0001) in APAH-CTD, and a decrease in pulmonary vascular resistance (SMD - 0.65, p < 0.0001) and elevated oxygen saturation (SMD 0.30, p = 0.006) in APAH-CHD. Importantly, in all pooled studies, the overall survival indicated 1-, 2-, and 3-year survival rates of 94.3%, 88.8%, and 81.7%, respectively, in all-cause PAH, and subgroup analysis demonstrated a relative decreasing trend in patients with HIV, from a 2-year survival of 89.8% to a 3-year survival of 66.1%. Adverse drug reactions were relatively mild.

CONCLUSION

In this systematic review and meta-analysis, long-term administration of oral bosentan has been identified as a well-tolerated and effective agent in different types of PAH. In addition, we conclude that long-term oral bosentan should be considered for patients with CTD to achieve a satisfactory exercise capacity, and for those with APAH-HIV to improve survivals, where more attention on adverse events is required.

Where on the Differential Is Eisenmenger Syndrome in a Patient Without Prior Cardiopulmonary Disease?

Pulmonary hypertension (PH) can occur in patients with undiagnosed congenital heart disease, like atrial septal defects (ASDs), causing chronic left-to-right shunting. This may ultimately result in Eisenmenger physiology or syndrome (ES), a reversal of left-to-right shunting, resulting in a right-to-left shunt, thereby causing deoxygenated blood to enter systemic circulation as it bypasses the lungs. Development of PH due to an ASD is uncommon, and the occurrence of ES is <1% as most ASDs are corrected early in life. We present a 28-year-old female presenting with new-onset dyspnea found to have an undiagnosed ASD with ES.

A 28-year-old female without past medical history presented to the emergency department after a chest x-ray performed by her primary care physician (PCP) showed dilation of the pulmonary artery concerning PH. The patient reported a three-month history of progressively worsening intermittent palpitations and dyspnea, now unable to walk more than one block without becoming dyspneic. Further imaging studies revealed a 1.4 centimeters (cm) secundum ASD, 4.4 cm dilatation of the PA, a mean pulmonary artery pressure (PAPm) of 132 millimeters (mm) mercury (Hg), and Eisenmenger physiology. She was placed on pulmonary vasodilators and iron supplementation to address an underlying iron-deficiency anemia. The patient is stable on her current regimen and is undergoing evaluation for possible heart-lung transplantation at an outside hospital.

Dyspnea is one of the top 10 most common indications for emergency room visits annually. The differential diagnosis for dyspnea is vast, with ES, affecting only 0.8 in 1 million, far down on the list of possibilities, thus requiring high clinical suspicion to prompt further evaluation. Ultimately, the condition is preventable with early identification of underlying structural abnormalities for which definitive treatment options exist and are readily available, dramatically improving the prognosis if implemented before ES develops.

Integrating Data From Randomized Controlled Trials and Observational Studies to Assess Survival in Rare Diseases

Supplemental Digital Content is available in the text.

Background:

Conducting randomized controlled trials to investigate survival in a rare disease like pulmonary arterial hypertension has considerable ethical and logistical constraints. In many studies, such as the Study with an Endothelin Receptor Antagonist in Pulmonary Arterial Hypertension to Improve Clinical Outcome (SERAPHIN) randomized controlled trial, evaluating survival is further complicated by bias introduced by allowing active therapy among placebo-treated patients who clinically deteriorate.

Methods and Results:

SERAPHIN enrolled and followed patients in the same time frame as the US Registry to Evaluate Early And Long-term PAH Disease Management, providing an opportunity to compare observed survival for SERAPHIN patients with predicted survival had they received real-world treatment as in the Registry to Evaluate Early And Long-term PAH Disease Management. From the Registry to Evaluate Early And Long-term PAH Disease Management (N=3515), 734 patients who met SERAPHIN eligibility criteria were selected and their data used to build a prediction model for time to death up to 3 years based on 10 baseline prognostic variables. The model was used to predict a survival curve for each of the 742 SERAPHIN patients via their baseline variables. The average of these predicted survival curves was compared with observed survival of the placebo (n=250) and macitentan 10 mg (n=242) groups using a log-rank test and Cox proportional hazard model. Observed mortality risk for patients randomized to placebo, 62% of whom were taking background pulmonary arterial hypertension therapy, tended to be lower than that predicted for all SERAPHIN patients (16% lower; P=0.259). The observed placebo survival curve closely approximated the predicted survival curve for the first 15 months. Beyond that time, observed risk of mortality decreased compared with predicted mortality, potentially reflecting the impact of crossover of patients in the placebo group to active therapy. Over 3 years, risk of mortality observed with macitentan 10 mg was 35% lower than predicted mortality (P=0.010).

Conclusions:

These analyses show that, in a rare disease, real-world observational data can complement randomized controlled trial data to overcome some challenges associated with assessing survival in the setting of a randomized controlled trial.

Clinical Trial Registration:

https://www.clinicaltrials.gov. Unique identifiers: NCT00660179 and NCT00370214.

Pulmonary arterial hypertension specific therapy: The old and the new

Pulmonary arterial hypertension (PAH) is a vascular disorder associated with high morbidity and mortality rate and is characterized by pulmonary vascular remodeling and increased pulmonary vascular resistance, ultimately resulting in right ventricular failure and death. Over the past few decades, significant advances in the understanding of the epidemiology, pathogenesis, and pathophysiology of pulmonary arterial hypertension have occured. This has led to the development of disease specific treatment including prostanoids, endothelin receptor antagonists, phosphodiesterase inhibitors, and soluble guanylate cyclase stimulators. These therapies significantly improve exercise capacity, quality of life, pulmonary hemodynamics, but none of the current treatments are actually curative and long-term prognosis remains poor. Thus, there is a clear need to develop new therapies. Several potential pharmacologic agents for the treatment of pulmonary arterial hypertension are under clinical development and some promising results with these treatments have been reported. These agents include tyrosine protein kinase inhibitors, rho-kinase inhibitors, synthetically produced vasoactive intestinal peptide, antagonists of the 5-HT2 receptors, and others. This article will review several of these promising new therapies and will discuss the current evidence regarding their potential benefit in pulmonary arterial hypertension.

Regional right ventricular longitudinal systolic strain for detection of severely impaired right ventricular performance in pulmonary hypertension

OBJECTIVES

Right ventricular (RV) function is identified as a key determinant of the outcome in patients with pulmonary hypertension (PH). Several studies have assessed the role of peak global longitudinal RV strain in PH patients; however, less emphasis was given to the RV regional longitudinal strain. The aim of this study was to evaluate the regional RV systolic strain in PH patients and investigate the relationship of these parameters with the severity of PH.

METHODS

RV regional longitudinal peak systolic strain (LPSS) and strain rate (LPSSR) were measured using speckle tracking echocardiography on 100 patients with PH who underwent right heart catheterization, and 29 control subjects. Severe PH was identified by a decreased cardiac index (CI) (<2.0 L/min/m² ).

RESULTS

LPSS and LPSSR of the RV free wall were significantly lower in PH patients than control subjects, especially when comparing the basal and mid regions (P < .001). When comparing severe PH and nonsevere PH, basal and mid LPSS and LPSSR were significantly lower (P < .001). RV free wall mid LPSSR correlated with CI (r = -.703, P < .001). In the multiple logistic regression analysis, mid LPSSR was identified as an independent predictor of severe PH (odds ratio 1.82; 95% confidential interval 1.39-2.40; P < .001). In the receiver operating characteristics curve analysis, a cutoff value of mid LPSSR of -0.92 s^-1 predicted severe PH, with a sensitivity and specificity of 75.0% and 93.7%, respectively (AUC = 0.889, P < .001).

CONCLUSIONS

RV free wall mid longitudinal peak systolic strain rate may be useful for the detection of severely impaired RV performance in PH.

Cardiopulmonary exercise test indices of respiratory buffering before and after aerobic exercise training in women with pulmonary hypertension: Differentiation by magnitudes of change in six-minute walk test performance

While aerobic exercise training (AET) has generally been shown to improve 6-min walk test (6MWT) distance (6MWD) in patients with pulmonary hypertension (PH), a substantial number of patients appear to adapt differently, with minimal or even negative changes in 6MWT distance being reported.

PURPOSE

To compare post-aerobic exercise training adaptations in cardiorespiratory functional capacity across three groups of patients with PH: those with high (HI), low (LI) and negative (NEG) post-training increases in 6MWD.

METHODS

Participants were 25 females (age 54 ± 11 years; BMI 31 ± 7 kg/m²) who completed a vigorous, 10-week, thrice weekly, supervised treadmill walking exercise program. Cardiopulmonary exercise tests (CPET) and 6MWT were completed before and after training. Ten of the 25 participants were classified as HI (range = 47-143 m), 11 were classified as LI (range = 4-37 m) and 4 were classified as NEG (range = -17 to -53 m).

RESULTS

Peak CPET duration, WR and time to anaerobic threshold (AT) were significantly higher (p < 0.05) after training in both the LI and HI groups but not in the NEG group. There was a significant improvement in VE/VCO₂ (p = 0.042), PETCO₂ (p = 0.011) and TV (p = 0.050) in the HI group after training, but not in the NEG or LI group.

CONCLUSION

These findings suggest that sustained ventilatory inefficiency and restricted respiratory buffering may mediate exercise intolerance and impede the ability to adapt to exercise training in some patients with PH.

Effect of Radiation Doses to the Heart on Survival for Stereotactic Ablative Radiotherapy for Early-stage Non-Small-cell Lung Cancer: An Artificial Neural Network Approach

INTRODUCTION

The cardiac radiation dose is an important predictor of cardiac toxicity and overall survival (OS) for patients with locally advanced non-small-cell lung cancer (NSCLC). However, radiation-induced cardiac toxicity among patients with early-stage NSCLC who have undergone stereotactic ablative radiotherapy (SABR) has been less well-characterized. Our objective was to assess the associations between cardiac radiation dosimetry and OS in patients with early-stage NSCLC undergoing SABR.

MATERIALS AND METHODS

From 2009 to 2014, 153 patients with early-stage NSCLC had undergone SABR at a single institution. The maximum dose, mean dose, V_10Gy, V_25Gy, and V_50Gy to 15 cardiac substructures and the whole heart were analyzed for their association with OS using the Kaplan-Meier method. An artificial neural network (ANN) analysis was performed to modulate confounding behaviors of dosimetric variables to predict for OS.

RESULTS

A total of 112 patients were included in the present analysis. The right ventricle (RV) V_10Gy most negatively predicted for OS, such that patients who had received a RV V_10Gy dose < 4% had significantly longer OS than patients who had received a RV V_10Gy does > 4% (5.3 years vs. 2.4 years). On ANN analysis, 74 input features, including cardiac dosimetry parameters, predicted for survival with a test accuracy of 64.7%. A repeat ANN analysis using dosimetry to dose neutral structure confirmed the predictive power of cardiac dosimetry.

CONCLUSION

Cardiac dosimetry to subvolumes of the heart was associated with decreased OS in patients with early-stage NSCLC undergoing SABR. These data support the importance of minimizing the radiation dose to cardiac substructures. Further prioritizing the heart as an organ at risk might be warranted. Additionally, cardiac follow-up should be considered.

Downregulation of miR‑98 contributes to hypoxic pulmonary hypertension by targeting ALK1

Chronic hypoxia is one of the most common causes of secondary pulmonary hypertension, the mechanisms of which remain unclear. MicroRNAs (miRNAs) are small, noncoding RNAs that inhibit the translation or accelerate the degradation of mRNA. Previous studies have demonstrated that deregulated miRNA expression contributes to various cellular processes including cell apoptosis and proliferation, which are mediated by hypoxia. In the present study, the expression of miR‑98 was identified to be decreased in the lung tissue of a hypoxic pulmonary hypertension (HPH) rat model and pulmonary artery (PA) smooth muscle cells (PASMCs), which was induced by hypoxia. By transfecting miR‑98 mimics into PASMCs, the high expression of miR‑98 inhibited cell proliferation, but upregulated hypoxia‑induced PASMCs apoptosis. However, these effects of miR‑98 mimics on PASMCs were reversed by ALK1 (activin receptor‑like kinase‑1) overexpression. ALK1 was identified as a candidate target of miR‑98. In addition, overexpressing miR‑98 markedly decreased the pulmonary artery wall thickness and the right ventricular systolic pressure in rats induced by hypoxia. These results provided clear evidence that miR‑98 was a direct regulator of ALK1, and that the downregulation of miR‑98 contributed to the pathogenesis of HPH. These results provide a novel potential therapeutic strategy for the treatment of HPH.

Goal-Oriented Sequential Combination Therapy Evaluated Using Cardiopulmonary Exercise Parameters for the Treatment of Newly Diagnosed Pulmonary Arterial Hypertension - Goal-Oriented Therapy Evaluated by Cardiopulmonary Exercise Testing for Pulmonary Arterial Hypertension (GOOD EYE)

Background: Many treatment options are available for pulmonary arterial hypertension (PAH), but specific recommendations for long-term treatment are unavailable. We compared prognosis in PAH patients receiving goal-oriented, sequential combination therapy evaluated using cardiopulmonary exercise testing (CPX) parameters or conventional empiric therapy.

Methods and Results: The Goal-Oriented Therapy Evaluated by Cardiopulmonary Exercise Testing for Pulmonary Arterial Hypertension (GOOD EYE) study was a multicenter, retrospective/prospective study in which a total of 129 patients with newly diagnosed PAH were enrolled (goal-oriented sequential combination therapy, n=42; conventional empiric therapy, n=87). Patients in the goal-oriented therapy group received sequential combination therapy, the efficacy of which was regularly evaluated using CPX parameters. Patients in the conventional empiric therapy group received conventional empiric therapy. The primary endpoint was cardiovascular death. In the goal-oriented therapy group, plasma brain natriuretic peptide, mean pulmonary arterial pressure, pulmonary vascular resistance, and 6-min walk test were significantly improved at 12 months compared with baseline. Survival in the goal-oriented therapy group at 1, 2, and 3 years (97.6%, 95.2%, and 86.0%, respectively) tended to be higher than that in the conventional empiric therapy group (P=0.082).

Conclusions: Goal-oriented sequential combination therapy evaluated using CPX parameters may be associated with a favorable prognosis compared with conventional empiric therapy in patients with newly diagnosed PAH.

Improving Survival in Patients with Pulmonary Arterial Hypertension: Focus on Intravenous Epoprostenol

Pulmonary arterial hypertension represents a devastating disease, causing progressive increase of pulmonary vascular resistance leading to right ventricular dysfunction and death. Therapeutic management has rapidly advanced in recent years due to improved understanding of pathophysiology and new drugs have been developed; however, survival remains poor. Oral agents as phosphodiesterase type V inhibitors, the soluble guanylyl cyclase stimulator riociguat, the prostacyclin receptor agonist selexipag and the endothelin receptor antagonists have each achieved evidence-based validation and are recommended for pulmonary arterial hypertension. Initial oral monotherapy or combination therapy is recommended for patients with low or intermediate risk according to each patient's risk stratification. Intravenous epoprostenol is a synthetic prostacyclin and the first drug approved for the disease. Although it represents the only treatment shown to reduce mortality, it is underused. Survival rates for patients treated with oral combination drug therapies are lower than those for patients treated with initial combination therapies including intravenous epoprostenol. This raises the interesting question of whether intermediate risk pulmonary arterial hypertension patients should be routinely introduced to therapies including intravenous epoprostenol rather than combination oral therapies.

Elucidation of Vasodilation Response and Structure Activity Relationships of N²,N⁴-Disubstituted Quinazoline 2,4-Diamines in a Rat Pulmonary Artery Model

Pulmonary arterial hypertension (PAH) is a rare and progressive disease arising from various etiologies and pathogenesis. PAH decreases life expectancy due to pulmonary vascular remodeling, elevation of mean pulmonary arterial pressure, and ultimately progresses to heart failure. While clinical treatments are available to reduce the associated symptoms, a complete cure has yet to be found. Phosphodiesterase-5 (PDE-5) inhibition has been identified as a possible intervention point in PAH treatment. The functional vasodilation response to N²,N⁴-diamino quinazoline analogues with differing PDE-5 inhibitory activities and varying physicochemical properties were assessed in both endothelium-intact and denuded rat pulmonary arteries to gain greater insight into their mode of action. All analogues produced vasorelaxant effects with EC50s ranging from 0.58 ± 0.22 µM to ˃30 µM. It was observed that vasodilation response in intact vessels was highly correlated with that of denuded vessels. The ~10% drop in activity is consistent with a loss of the nitric oxide mediated cyclic guanosine monophosphate (NO/cGMP) pathway in the latter case. A moderate correlation between the vasodilation response and PDE-5 inhibitory activity in the intact vessels was observed. Experimental protocol using the alpha-adrenergic (α₁) receptor agonist, phenylephrine (PE), was undertaken to assess whether quinazoline derivatives showed competitive behavior similar to the α₁ receptor blocker, prazosin, itself a quinazoline derivative, or to the PDE-5 inhibitor, sildenafil. Competitive experiments with the α₁-adrenergic receptor agonist point to quinazoline derivatives under investigation here act via PDE-5 inhibition and not the former. The pre-incubation of pulmonary arterial rings with quinazoline test compounds (10 μM) reduced the contractile response to PE around 40–60%. The most promising compound (9) possessed ~32 folds higher selectivity in terms of vasodilation to its mammalian A549 cell cytotoxicity. This study provides experi0 0mental basis for PDE-5 inhibition as the mode of action for vasodilation by N²,N⁴-diamino quinazoline analogues along with their safety studies that may be beneficial in the treatment of various cardiovascular pathologies.

The improvement of pulmonary artery pressure after bosentan therapy in patients with β-thalassemia and Doppler-defined pulmonary arterial hypertension

Introduction

Pulmonary arterial hypertension (PAH) is relatively prevalent in patients with thalassemia. PAH treatment is necessary as the prevalence of Doppler-estimated PAH and the resultant mortality is high in such patients.

Materials and methods

This study aimed at evaluating the effect of bosentan therapy on patients with thalassemia suspected of PAH. Based on pulsed Doppler echocardiography, all the cases were suspected of severe PAH. Consequently, bosentan was initiated at a dose of 62.5 mg twice a day for 4 weeks, which was increased to 62.5–125 mg twice a day, if no adverse side effects were observed.

Results

The results of this study showed that pulmonary artery pressure (PAP) decreased after the administration of bosentan in three cases, from 160 to 120, 110 to 65, and 60 to 25 mmHg; in other words, the PAP reduced in the mentioned cases by 25%, 36.4%, and 58.4%, respectively.

Conclusion

In this study, PAP improved after bosentan therapy in patients with β-thalassemia suspected of PAH; however, further studies are required to confirm the findings.

A modified risk score in one-year survival rate assessment of group 1 pulmonary arterial hypertension

BACKGROUND

Risk assessment of pulmonary arterial hypertension (PAH) contributes to its management. Unfortunately, the existing risk assessment approaches are defective for clinicians to practice in daily clinical settings to some extent.

METHODS

We designed a modified Risk Assessment Score of PAH (mRASP) comprising four non-invasive variables which were World Health Organization functional class(WHO FC), 6-min walk distance (6MWD), N-terminal of the pro-hormone brain natriuretic peptide(NT-pro BNP), and right atrial area(RAA), then validated it in the prediction of one-year survival rate for patients with PAH by contrast with the REVEAL risk score.

RESULTS

For the validation cohort(n = 216), the predicted one-year survival rate were 95-100%, 90-95%, and < 90% in the mRASP risk score strata of 0-2, 3-5, and 6-8, respectively; meanwhile, the observed one-year survival rates were 97.1, 92.6, and 52.2%, in each corresponding stratum, respectively. The mRASP (c-index = 0.727) demonstrated similar predictive power in contrast with the REVEAL risk assessment score (c-index = 0.715) in the prediction of one-year survival rate.

CONCLUSION

The mRASP is an eligible risk assessment tool for the prognostic assessment of PAH. In contrast with the REVEAL score, it demonstrated similar predictive power and accuracy, with extra simplicity and convenience.

Endothelin-receptor antagonists in the management of pulmonary arterial hypertension: where do we stand?

Pulmonary arterial hypertension, a disease largely neglected until a few decades ago, is presently the object of intense studies by several research teams. Despite considerable progress, pulmonary arterial hypertension remains a major clinical problem, because it is not always easy to diagnose, treat, and prevent. The disease was considered incurable until the late 1990s, when Epoprostenol was introduced as the first tool against this illness. More recently, therapy for pulmonary arterial hypertension gained momentum after publication of the SERAPHIN and AMBITION trials, which also highlighted the importance of upfront therapy. This review also focuses on recent substudies from these trials and progress in drugs targeting the endothelin pathway. Future perspectives with regard to endothelin-receptor antagonists are also discussed.

Risk stratification strategy and assessment of disease progression in patients with pulmonary arterial hypertension: Updated Recommendations from the Cologne Consensus Conference 2018

In the summer of 2016, delegates from the German Respiratory Society, the German Society of Cardiology and the German Society of Pediatric Cardiology met in Cologne, Germany, to define consensus-based practice recommendations for the management of patients with pulmonary arterial hypertension (PAH). These recommendations were built on the 2015 European Pulmonary Hypertension guidelines and included new evidence, where available, and were last updated in the spring of 2018. This article focusses on the proposed risk stratification and assessment of disease progression in patients with pulmonary arterial hypertension (PAH), covering 3 parts: In part 1, methods and markers that are recommended to assess severity and progression of PAH are discussed and commented. These updated comments incorporate most recent data as well as challenges arising from the variability of phenotypes of PAH patients with increasing cardiopulmonary comorbidities. In part 2, the proposed ESC/ERS risk stratification strategy is discussed, together with a review of the recent validation studies from different European registries. Finally, in part 3, the working group of the Cologne Consensus Conference provides recommendations on how risk assessment may be implemented in routine clinical practice and may serve clinical decision making.

The Regulation of Pulmonary Vascular Tone by Neuropeptides and the Implications for Pulmonary Hypertension

Pulmonary hypertension (PH) is an incurable, chronic disease of small pulmonary vessels. Progressive remodeling of the pulmonary vasculature results in increased pulmonary vascular resistance (PVR). This causes secondary right heart failure. PVR is tightly regulated by a range of pulmonary vasodilators and constrictors. Endothelium-derived substances form the basis of most current PH treatments. This is particularly the case for pulmonary arterial hypertension. The major limitation of current treatments is their inability to reverse morphological changes. Thus, there is an unmet need for novel therapies to reduce the morbidity and mortality in PH. Microvessels in the lungs are highly innervated by sensory C fibers. Substance P and calcitonin gene-related peptide (CGRP) are released from C-fiber nerve endings. These neuropeptides can directly regulate vascular tone. Substance P tends to act as a vasoconstrictor in the pulmonary circulation and it increases in the lungs during experimental PH. The receptor for substance P, neurokinin 1 (NK1R), mediates increased pulmonary pressure. Deactivation of NK1R with antagonists, or depletion of substance P prevents PH development. CGRP is a potent pulmonary vasodilator. CGRP receptor antagonists cause elevated pulmonary pressure. Thus, the balance of these peptides is crucial within the pulmonary circulation (Graphical Abstract). Limited progress has been made in understanding their impact on pulmonary pathophysiology. This is an intriguing area of investigation to pursue. It may lead to promising new candidate therapies to combat this fatal disease. This review provides a summary of the current knowledge in this area. It also explores possible future directions for neuropeptides in PH.

ITE inhibits growth of human pulmonary artery endothelial cells

AIM

Pulmonary arterial hypertension (PAH), a deadly disorder is associated with excessive growth of human pulmonary artery endothelial (HPAECs) and smooth muscle (HPASMCs) cells. Current therapies primarily aim at promoting vasodilation, which only ameliorates clinical symptoms without a cure. 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) is an endogenous aryl hydrocarbon receptor (AhR) ligand, and mediates many cellular function including cell growth. However, the roles of ITE in human lung endothelial cells remain elusive. Herein, we tested a hypothesis that ITE inhibits growth of human pulmonary artery endothelial cells via AhR.

MATERIALS AND METHODS

Immunohistochemistry was performed to localize AhR expression in human lung tissues. The crystal violet method and MTT assay were used to determine ITE's effects on growth of HPAECs. The AhR activation in HPAECs was confirmed using Western blotting and RT-qPCR. The role of AhR in ITE-affected proliferation of HPAECs was assessed using siRNA knockdown method followed by the crystal violet method.

RESULTS

Immunohistochemistry revealed that AhR was present in human lung tissues, primarily in endothelial and smooth muscle cells of pulmonary veins and arteries, as well as in bronchial and alveolar sac epithelia. We also found that ITE dose- and time-dependently inhibited proliferation of HPAECs with a maximum inhibition of 83% at 20 µM after 6 days of treatment. ITE rapidly decreased AhR protein levels, while it increased mRNA levels of cytochrome P450 (CYP), family 1, member A1 (CYP1A1) and B1 (CYP1B1), indicating activation of the AhR/CYP1A1 and AhR/CYP1B1 pathways in HPAECs. The AhR siRNA significantly suppressed AhR protein expression, whereas it did not significantly alter ITE-inhibited growth of HPAECs.

CONCLUSIONS

ITE suppresses growth of HPAECs independent of AhR, suggesting that ITE may play an important role in preventing excessive growth of lung endothelial cells.

Treatment strategies for the right heart in pulmonary hypertension

The function of the right ventricle (RV) determines the prognosis of patients with pulmonary hypertension. While much progress has been made in the treatment of pulmonary hypertension, therapies for the RV are less well established. In this review of treatment strategies for the RV, first we focus on ways to reduce wall stress since this is the main determinant of changes to the ventricle. Secondly, we discuss treatment strategies targeting the detrimental consequences of increased RV wall stress. To reduce wall stress, afterload reduction is the essential. Additionally, preload to the ventricle can be reduced by diuretics, by atrial septostomy, and potentially by mechanical ventricular support. Secondary to ventricular wall stress, left-to-right asynchrony, altered myocardial energy metabolism, and neurohumoral activation will occur. These may be targeted by optimising RV contraction with pacing, by iron supplement, by angiogenesis and improving mitochondrial function, and by neurohumoral modulation, respectively. We conclude that several treatment strategies for the right heart are available; however, evidence is still limited and further research is needed before clinical application can be recommended.

Right ventricle performances with echocardiography and 99mTc myocardial perfusion imaging in pulmonary arterial hypertension patients

Right heart catheterization is commonly used to measure right ventricle hemodynamic parameters and is the gold standard for pulmonary arterial hypertension diagnosis; however, it is not suitable for patients' long-term follow-up. Non-invasive echocardiography and nuclear medicine have been applied to measure right ventricle anatomy and function, but the guidelines for the usefulness of clinical parameters remain to be established. The goal of this study is to identify reliable clinical parameters of right ventricle function in pulmonary arterial hypertension patients and analyze the relationship of these clinical parameters with the disease severity of pulmonary arterial hypertension. In this study, 23 normal subjects and 23 pulmonary arterial hypertension patients were recruited from January 2015 to March 2016. Pulmonary arterial hypertension patients were classified into moderate and severe pulmonary arterial hypertension groups according to their mean pulmonary arterial pressure levels. All the subjects were subjected to physical examination, chest X-ray, 12-lead electrocardiogram, right heart catheterization, two-dimensional echocardiography, and technetium 99m (^99mTc) myocardial perfusion imaging. Compared to normal subjects, the right heart catheterization indexes including right ventricle systolic pressure, right ventricle end diastolic pressure, pulmonary artery systolic pressure, pulmonary artery diastolic pressure, pulmonary vascular resistance, and right ventricle end systolic pressure increased in pulmonary arterial hypertension patients and were correlated with mean pulmonary arterial pressure levels. Echocardiography parameters, including tricuspid regurgitation peak velocity, tricuspid regurgitation pressure gradient, tricuspid annular plane systolic excursion and fractional area, right ventricle-myocardial performance index, were significantly associated with the mean pulmonary arterial pressure levels in pulmonary arterial hypertension patients. Furthermore, myocardial perfusion imaging was not observed in the normal subjects but in pulmonary arterial hypertension patients, especially severe pulmonary arterial hypertension subgroup, and showed potential diagnostic properties for pulmonary arterial hypertension. In conclusion, mean pulmonary arterial pressure levels are correlated with several right heart catheterization and echocardiography markers in pulmonary arterial hypertension patients; echocardiography and ^99mTc myocardial perfusion can be used to evaluate right ventricle performance in pulmonary arterial hypertension patients. Impact statement In this study, we analyzed the clinical parameters for evaluating RV function, including right ventricle catheterization (RHC), echocardiography, and technetium 99m (^99mTc) myocardial perfusion imaging (MPI) in normal Asian subjects and PAH patients ( n = 23 for each group). Our results demonstrated that six RHC indexes, four echocardiography indexes and MPI index were significantly altered in PAH patients and correlated with the levels of mean pulmonary arterial pressure. Importantly, we evaluated the diagnostic performance of MPI and found that MPI has a strong diagnostic accuracy in PAH patients. The findings from this study will be of interest to clinical investigators who make diagnosis and therapeutic strategies for PAH patients.

Medical therapies for pulmonary arterial hypertension

Pulmonary Arterial hypertension (PAH) is a chronic and progressive disease characterized by an increase in pulmonary vascular resistance due to severe remodeling of the small pulmonary arteries. In PAH, the endothelial cells fail to maintain their homeostatic balance, with the consequent impaired production of vasodilators and over-expression of vasoconstrictors and proliferators. Current treatment of PAH is based on the discovery of three main pathways of endothelial dysfunction (prostacyclin, nitric oxide and endothelin-1), and includes drugs such as prostacyclin analogs, phosphodiesterase-5 inhibitors and endothelin receptor antagonists (ERAs). Recently approved drugs that act through these classic pathways include riociguat (cyclic GMP stimulator) and macitentan (a tissue specific dual ERA). However, several new drugs and new pathways are under study. New targeted therapies include tyrosine kinase inhibitors, Rho kinase inhibitors and serotonin receptor blockers. There are now ten drugs approved for the treatment of PAH that, alone or in combination, have changed the natural history of this disease. The new drugs will allow us to further modified the patients' life expectancy and move towards a cure.

Current Trends and Future Perspectives in the Treatment of Pulmonary Arterial Hypertension

Pulmonary hypertension continues to be a life-threatening illness with debilitating physical and emotional consequences affecting around 1% of global population. The progression of this devastating disease is characterized by increase in pulmonary vascular resistance resulting in elevated pulmonary pressure, eventually leading to right heart failure and death. Better understanding of pathophysiology has led to substantial improvements in terms of availability of treatment options. The purpose of this review is to summarize the currently available treatment options along with pertinent trials and possible future therapies of pulmonary arterial hypertension.

Follow-Up of Pulmonary Hypertension With Echocardiography

Individual patient response to effective therapies for pulmonary hypertension (PAH) is variable and difficult to quantify. Consequently, management decisions regarding initiation and continuation of therapy are highly dependent on the results of investigations. Registry data show that changes in cardiac index, mean right atrial pressure, and mean pulmonary artery pressure have the greatest influence on survival. It is recognized that pulmonary artery pressure (PASP) responses to PAH-specific drugs are heterogeneous. However, follow-up testing is strongly focused on assessing changes in PASP and functional status (6-min walk). The goals of therapy, which should be highlighted in follow-up imaging, include not only reduction of PASP, decrease in pulmonary vascular resistance, and improvements in right ventricular function, cardiac output, and tricuspid regurgitation. This paper reviews the echocardiographic follow-up of pulmonary hypertension, and especially focuses on right ventricular function-a major determinant of outcome, for which reliable echocardiographic assessment has become more feasible.

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.

Pulmonary arterial hypertension - progress in understanding the disease and prioritizing strategies for drug development

Pulmonary arterial hypertension (PAH), at one time a largely overlooked disease, is now the subject of intense study in many academic and biotech groups. The availability of new treatments has increased awareness of the condition. This in turn has driven a change in the demographics of PAH, with an increase in the mean age at diagnosis. The diagnosis of PAH in more elderly patients has highlighted the need for careful phenotyping of patients and for further studies to understand how best to manage pulmonary hypertension associated with, for example, left heart disease. The breadth and depth of expertise focused on unravelling the molecular pathology of PAH has yielded novel insights, including the role of growth factors, inflammation and metabolic remodelling. The description of the genetic architecture of PAH is accelerating in parallel, with novel variants, such as those reported in potassium two-pore domain channel subfamily K member 3 (KCNK3), adding to the list of more established mutations in genes associated with bone morphogenetic protein receptor type 2 (BMPR2) signalling. These insights have supported a paradigm shift in treatment strategies away from simply addressing the imbalance of vasoactive mediators observed in PAH towards tackling more directly the structural remodelling of the pulmonary vasculature. Here, we summarize the changing clinical and molecular landscape of PAH. We highlight novel drug therapies that are in various stages of clinical development, targeting for example cell proliferation, metabolic, inflammatory/immune and BMPR2 dysfunction, and the challenges around developing these treatments. We argue that advances in the treatment of PAH will come through deep molecular phenotyping with the integration of clinical, genomic, transcriptomic, proteomic and metabolomic information in large populations of patients through international collaboration. This approach provides the best opportunity for identifying key signalling pathways, both as potential drug targets and as biomarkers for patient selection. The expectation is that together these will enable the prioritization of potential therapies in development and the evolution of personalized medicine for PAH.

Impact of advanced medical therapy for the outcome of an adult patient with Eisenmenger syndrome

Eisenmenger syndrome (ES) is the most severe form of pulmonary arterial hypertension (PAH) associated with congenital heart disease. It is an extremely devastating condition with a serious impact on patients' life. Classical therapy of ES remains directed to avoid complications, such as erythrocytosis, treatment of congestive heart failure, prevention of infection, and secondary haematological abnormalities such as iron deficiency and coagulation disorders. However, the only effective treatment is heart–lung transplantation; still, morbidity and mortality after transplantation remain substantially high. Furthermore, waiting lists for heart–lung transplantation are long. Recent studies examining the use of advanced medical treatment in patients with ES have shown that it may have beneficial effects in patients with ES; however, additional studies need to be done to confirm its efficacy and appropriate clinical use. A 41-year-old female admitted to the Hospital of Lithuanian University of Health Sciences due to progressive dyspnea on minimal effort, heart failure symptoms leading to NYHA functional class III-IV. After clinical and instrumental investigations, ES secondary to unrepaired patent ductus arteriosus with severe PAH was diagnosed. Treatment with sildenafil was initiated together with the standard pharmacological therapy, and the patient was added to the waiting list for the heart and lung transplantation. After 24 months of stable condition, her clinical status deteriorated, and combination therapy (sildenafil and ambrisentan) was initiated. Clinical symptoms and exercise capacity improved, and she has been stable for 4 years thereafter. Our experience of the management of an adult patient with ES showed the benefits of treatment with advanced therapy with pulmonary vasodilators that improved the patient's quality of life and delayed the need for heart and lung transplantation.

Circulatory power and ventilatory power over time under goal-oriented sequential combination therapy for pulmonary arterial hypertension

Many therapeutic options are available for patients with pulmonary arterial hypertension (PAH). However, little is known about the effects of sequential combination therapy on exercise capacity. Here we monitored exercise capacity by cardiopulmonary exercise testing (CPX) and observed the benefit of using a peak VO₂ cutoff of 15 mL/kg/min to guide combination therapy. Thirty patients newly diagnosed with PAH were treated with goal-oriented sequential combination therapy. Endothelin receptor antagonists (ERA) were the first-line treatment, with phosphodiesterase type 5 inhibitors (PDE-5i) as the preferred combination partner. The patients underwent cardiac catheterization at baseline and after 12 months and CPX at baseline and after three, six, and 12 months. Circulatory power (CP) was defined as the product of peak O₂ uptake and peak systolic blood pressure (SBP); ventilatory power (VP) was defined as peak SBP divided by the minute ventilation–CO₂ production slope. After 12 months, ERA had been administered to 100% of the study patients and PDE-5i to 82%. Mean CP at baseline and after three, six, and 12 months was 1807, 2063, 2248, and 2245 mmHg·min/mL/kg, respectively, and mean VP was 2.93, 3.53, 4.16, and 3.68 mmHg, respectively. CP was greater after 6 months than at baseline (P = 0.047); VP was greater after three months than at baseline (P = 0.019) and further improved at six months compared with three months (P = 0.040). Therefore, repeated CPX assessment, including measurement of CP and VP, can provide useful information regarding the efficacy of goal-oriented treatment for PAH.

Which prognostic factors should be used in pulmonary arterial hypertension in elderly patients?

In recent times, the prevalence of pulmonary arterial hypertension (PAH) is more commonly seen among elderly populations. The increased prevalence of hypertension, diabetes, obesity, arterial stiffness, as well as diastolic dysfunction, may cause endothelial dysfunction and affect pulmonary vasculature. Furthermore, older patients have certain differences in clinical characteristics and outcomes. In this article, the special characteristics of aging in PAH patients have been reviewed, while the risk predictors of elderly patients are also discussed.

Real-world, long-term survival of incident patients with pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease. Long-term outcomes data are scarce in Portugal. We aimed to estimate survival of newly diagnosed PAH at a Portuguese referral center in the modern management era.

METHODS

Between January 2009 and November 2015 all incident PAH cases were consecutively enrolled in a prospective cohort study. Sixty-five patients were followed up for a median of 3.1 [interquartile range 1.7-5.4] years. Kaplan-Meier survival analysis was used to estimate 1-, 3-, and 5-year survival and to compare it with a historical PAH survival estimated from the NIH cohort.

RESULTS

Mean age was 48±19 years with female preponderance (68%). The most common PAH subgroup was congenital heart disease (PAH-CHD) (n=31; 48%), followed by connective tissue disease (PAH-CTD) (n=16; 25%), idiopathic (IPAH) (n=8; 12%) and hereditary (HPAP) (n=1; 1.5%). BNP values (hazard ratio [HR] 2.07; 95%CI 1.34-3.22; P=0.001) and male gender [HR 4.34 (1.44-13.09); P=0.009] were predictors of death. Survival rates at 1-, 3- and 5-years were 95%, 77% and 71%. Survival was not statistically different between PAH etiologies (Log-rank P=0.7). However, PAH-CHD was associated with a decreased risk of the combined endpoint of all-cause mortality and admission for decompensated heart failure [HR 0.36 (0.15-0.85); P=0.02]. We found a non-significant numerically higher survival of incident IPAH, HPAH and DPAH patients in comparison with the historical NIH cohort.

CONCLUSIONS

In this cohort of incident PAH patients, PAH-CHD patients had better overall prognosis. Higher BNP values and male gender were associated with higher mortality.

Systematic Review of Health-Related Quality of Life in Patients with Pulmonary Arterial Hypertension

BACKGROUND

The increasing survival of patients with pulmonary arterial hypertension (PAH) has shifted attention towards the disease burden that PAH imposes on patients and healthcare systems. Most studies emphasize epidemiology and medications, while large observational studies reporting on the health-related quality of life (HRQOL) of patients with PAH are lacking.

OBJECTIVE

Our objective was to study the HRQOL of patients with PAH and to summarize the factors that influence it.

METHODS

We conducted systematic literature searches in English (PubMed, Web of Knowledge, ScienceDirect and OVID) and Chinese (China National Knowledge Infrastructure, Wanfang Data, Chongqing VIP and SinoMed) databases to identify studies published from 2000 to 2015 assessing the HRQOL of patients with PAH. Search results were independently reviewed and extracted by two reviewers.

RESULTS

Of 3392 records identified in the initial search, 20 eligible papers (19 English, 1 Chinese) were finally included. Studies used a range of instruments; the generic 36-item Short Form Survey (SF-36) was the most widely used, and the disease-specific Cambridge Pulmonary Hypertension Outcome Survey (CAMPHOR) was the second mostly widely used. Mean HRQOL scores assessed via the SF-36 (physical component summary [PCS] 25.4-80.1; mental component summary [MCS] 33.2-76.0) and CAMPHOR (symptom scores 3.1-17; total HRQOL 2.8-12.6; activity scores 3.8-18.1) varied across studies, reporting decreased HRQOL in patients. Mental health (depression, anxiety, stress), physical health (exercise capacity, symptoms) and medical therapies were reported to affect HRQOL.

CONCLUSION

We found that PAH places a substantial burden on patients, particularly in terms of HRQOL; however, the paucity of large observational studies in this area requires the attention of researchers, especially in China.

Stability of an Extemporaneously Compounded Oral Suspension of Bosentan

PURPOSE

To assess the stability of an extemporaneously compounded oral suspension of bosentan from commercially available tablets for a period of 1 month.

METHODS

A 6.25 mg/mL oral suspension of bosentan monohydrate was prepared from Tracleer tablets. The bosentan suspension was then evenly divided between 2 light-resistant prescription bottles and stored in the dark either under refrigeration (4-8°C) or at controlled room temperature (21-26°C). The suspensions were assessed for physical changes (ease of resuspendability, change in color, change in odor), and samples were drawn immediately after preparation and on days 0, 1, 3, 7, 10, 14, 21, 28, and 31. Samples were analyzed at each time point by high-performance liquid chromatography (HPLC) utilizing a reversed-phase column with chemical stability defined as the retention of at least 90% of the initial intact bosentan concentration measured.

RESULTS

No change in suspendability, color, or odor of the compounded bosentan suspensions was noted throughout the storage period. Furthermore, regardless of storage conditions, the oral suspension of bosentan retained at least 94% of the active pharmaceutical ingredient for 31 days after preparation.

CONCLUSION

The results of our study indicate that a 6.25 mg/mL bosentan oral suspension stored in the dark under refrigeration and at room temperature maintains physical and chemical stability for 1 month.