Survival in patients with idiopathic, familial, and anorexigen-associated pulmonary arterial hypertension in the modern management era

Sex Differences in Right Ventricular Dysfunction: Insights From the Bench to Bedside

There are inherent distinctions in right ventricular (RV) performance based on sex as females have better RV function than males. These differences are magnified and have very important prognostic implications in two RV-centric diseases, pulmonary hypertension (PH), and arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). In both PH and ARVC/D, RV dysfunction results in poor patient outcomes. However, there are no currently approved therapies specifically targeting the failing RV, an important unmet need for these two life-threatening disorders. In this review, we highlight human data demonstrating divergent RV phenotypes in healthy, PH, and ARVC/D patients based on sex. Furthermore, we discuss the links between estrogen (the female predominant sex hormone), testosterone (the male predominant sex hormone), and dehydroepiandrosterone (a precursor hormone for multiple sex hormones in males and females) and RV function in both disorders. To provide potential mechanistic insights into sex differences in RV function, we review data that investigate how sex hormones combat or contribute to pathophysiological changes in the RV. Finally, we highlight the ongoing clinical trials in pulmonary arterial hypertension targeting estrogen and dehydroepiandrosterone signaling. Hopefully, a greater understanding of the factors that promote superior RV function in females will lead to novel therapeutic approaches to combat RV dysfunction in PH and ARVC/D.

Effects of Dual Initial Combination Therapy With Macitentan Plus Riociguat or Macitentan Plus Selexipag on Hemodynamics in Patients With Pulmonary Arterial Hypertension (SETOUCHI-PH Study) - Protocol of a Multicenter Randomized Control Trial

Background: The latest guideline from the European Society of Cardiology and European Respiratory Society recommends initial combination therapy with oral pulmonary arterial hypertension (PAH)-specific drugs in PAH patients with World Health Organization functional class (WHO-FC) II or III. However, whether this initial combination therapy improves hemodynamics and clinical failure events regardless of the combination of PAH-specific drugs remains unknown. This study was designed to evaluate whether the initial combination therapy with macitentan plus riociguat or macitentan plus selexipag showed equal efficacy in reducing pulmonary vascular resistance (PVR) 8 months after administration. Methods and Results: This study is a multicenter randomized control trial. PAH subjects with WHO-FC II or III will be randomized (1 : 1) into initial combination therapy with either macitentan plus riociguat or macitentan plus selexipag, and will be observed 8 months after the initiation of treatment. The primary endpoint will be the difference in the change ratio of PVR from baseline to after 8 months of treatment. Conclusions: The SETOUCHI-PH study will clarify whether initial combination therapy with macitentan plus riociguat or macitentan plus selexipag results in equal reductions in PVR 8 months after administration.

Persistent Pulmonary Hypertension in Corrected Valvular Heart Disease: Hemodynamic Insights and Long-Term Survival

Background The determinants and consequences of pulmonary hypertension after successfully corrected valvular heart disease remain poorly understood. We aim to clarify the hemodynamic bases and risk factors for mortality in patients with this condition. Methods and Results We analyzed long-term follow-up data of 222 patients with pulmonary hypertension and valvular heart disease successfully corrected at least 1 year before enrollment who had undergone comprehensive hemodynamic and imaging characterization as per the SIOVAC (Sildenafil for Improving Outcomes After Valvular Correction) clinical trial. Median (interquartile range) mean pulmonary pressure was 37 mm Hg (32-44 mm Hg) and pulmonary artery wedge pressure was 23 mm Hg (18-26 mm Hg). Most patients were classified either as having combined precapillary and postcapillary or isolated postcapillary pulmonary hypertension. After a median follow-up of 4.5 years, 91 deaths accounted for 4.21 higher-than-expected mortality in the age-matched population. Risk factors for mortality were male sex, older age, diabetes mellitus, World Health Organization functional class III and higher pulmonary vascular resistance-either measured by catheterization or approximated from ultrasound data. Higher pulmonary vascular resistance was related to diabetes mellitus and smaller residual aortic and mitral valve areas. In turn, the latter correlated with prosthetic nominal size. Six-month changes in the composite clinical score and in the 6-minute walk test distance were related to survival. Conclusions Persistent valvular heart disease-pulmonary hypertension is an ominous disease that is almost universally associated with elevated pulmonary artery wedge pressure. Pulmonary vascular resistance is a major determinant of mortality in this condition and is related to diabetes mellitus and the residual effective area of the corrected valve. These findings have important implications for individualizing valve correction procedures. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00862043.

A pilot study of oral treprostinil pharmacogenomics and treatment persistence in patients with pulmonary arterial hypertension

BACKGROUND AND AIMS

Treprostinil is a prostacyclin analog used to treat pulmonary arterial hypertension. Dosing is empiric and based on tolerability. Adverse effects are common and can affect treatment persistence. Pharmacogenomic variants that may affect treprostinil metabolism and transport have not been well-characterized. We aimed to investigate the pharmacogenomic sources of variability in treatment persistence and dosing.

METHODS

Patients were prospectively recruited from an IRB approved biobank registry at a single pulmonary hypertension center. A cohort of patients who received oral treprostinil were screened for participation. Pharmacogenomic analysis was for variants in CYP2C8, CYP2C9, and ABCC4. A retrospective review was conducted for demographics, clinical status, dosing, and response. Fisher's exact test was used for categorical data and Kruskal-Wallis test or Wilcoxon rank sum were used for continuous data.

RESULTS

A total of 15 patients received oral treprostinil and were consented. Their median age was 53 years, 73% were female, and 93% were White. The median total daily dose was 22.5 mg (13.5, 41) at last clinical observation. 40% of patients discontinued treatment with a majority due to adverse effects. Approximately 27% of patients had a loss-of-function variant in CYP2C8 (*1/*3 or *1/*4), whereas 47% of patients had a loss-of-function variant in CYP2C9 (*1/*2, *1/*3, or *2/*2). Minor allele frequencies for ABCC4 (rs1751034 and rs3742106) were 0.17 and 0.43, respectively. Survival analysis showed that increased CYP2C9 activity score was associated with decreased risk for treatment discontinuation [hazard ratio (HR): 0.13; 95% confidence interval (CI): 0.02, 0.91; p = 0.04]. Genetic variants were not significantly associated with dosing.

CONCLUSION

Genetic variants responsible for the metabolism and transport of oral treprostinil were common. Increased CYP2C9 activity score was associated with decreased risk for treatment discontinuation. However, dosing was not associated with genetic variants in metabolizing enzymes for treprostinil. Our findings suggest significant variability in treatment persistence to oral treprostinil, with pharmacogenomics being a potentially important contributor.The reviews of this paper are available via the supplemental material section.

Hemodynamic trajectories and outcomes in patients with pulmonary arterial hypertension

The relative pulmonary to systemic pressure ratio (mean pulmonary arterial pressure/mean arterial pressure) has been proven to be valuable in cardiac surgery. Little is known on the prognostic value of baseline and trajectory of mean pulmonary arterial pressure/mean arterial pressure in pulmonary arterial hypertension. Patients with confirmed idiopathic, familial, drug and toxins, or connective tissue disease-related pulmonary arterial hypertension and at least one complete right heart catheterization were included and prospectively followed-up for 5.9 ± 4.03 years. Correlates of the primary end point (i.e. death or lung transplant need) during follow-up were determined using Cox regression modeling. Results showed that among the 308 patients included, 187 had at least one follow-up catheterization (median time between catheterizations: 2.16 (1.16–3.19) years). In the total cohort (mean age 47.3 ± 14.9 years, 82.8% of female and 58.1% in New York Heart Association class 3 or 4), mean pulmonary arterial pressure/mean arterial pressure (1.38 (1.07–1.77)) was associated with outcome (p = 0.01). Mean pulmonary arterial pressure/mean arterial pressure was incremental to a basic model (including right atrial pressure, systolic blood pressure, New York Heart Association class 3 or 4, and connective tissue disease) for outcome prediction, while mean pulmonary arterial pressure was not. In the 187 patients with a follow-up catheterization, both delta mean pulmonary arterial pressure and delta mean pulmonary arterial pressure/mean arterial pressure were associated with outcome (1.32 (1.11–1.58) and 1.31 (1.1–1.57) respectively, p < 0.01). Mean pulmonary arterial pressure and mean pulmonary arterial pressure/mean arterial pressure were both incremental to the basic model, while worsening in mean pulmonary arterial pressure or mean pulmonary arterial pressure/mean arterial pressure did not reach significance. In conclusion, mean pulmonary arterial pressure/mean arterial pressure at baseline prognosticates long-term outcome with a significant, albeit modest, incremental value to basic variables.

Discovery of highly selective and orally available benzimidazole-based phosphodiesterase 10 inhibitors with improved solubility and pharmacokinetic properties for treatment of pulmonary arterial hypertension

Optimization efforts were devoted to discover novel PDE10A inhibitors in order to improve solubility and pharmacokinetics properties for a long-term therapy against pulmonary arterial hypertension (PAH) starting from the previously synthesized inhibitor A. As a result, a potent and highly selective PDE10A inhibitor, 14·3HCl (half maximal inhibitory concentration, IC₅₀ = 2.8 nmol/L and >3500-fold selectivity) exhibiting desirable solubility and metabolic stability with a remarkable bioavailability of 50% was identified with the aid of efficient methods of binding free energy predictions. Animal PAH studies showed that the improvement offered by 14·3HCl [2.5 mg/kg, oral administration (p.o.)] was comparable to tadalafil (5.0 mg/kg, p.o.), verifying the feasibility of PDE10A inhibitors for the anti-PAH treatment. The crystal structure of the PDE10A−14 complex illustrates their binding pattern, which provided a guideline for rational design of highly selective PDE10A inhibitors.

Treatment Targets for Right Ventricular Dysfunction in Pulmonary Arterial Hypertension

Right ventricle (RV) dysfunction is the strongest predictor of mortality in pulmonary arterial hypertension (PAH), but, at present, there are no therapies directly targeting the failing RV. Although there are shared molecular mechanisms in both RV and left ventricle (LV) dysfunction, there are important differences between the 2 ventricles that may allow for the development of RV-enhancing or RV-directed therapies. In this review, we discuss the current understandings of the dysregulated pathways that promote RV dysfunction, highlight RV-enriched or RV-specific pathways that may be of particular therapeutic value, and summarize recent and ongoing clinical trials that are investigating RV function in PAH. It is hoped that development of RV-targeted therapies will improve quality of life and enhance survival for this deadly disease.

Caregiver Burden in Patients with Pulmonary Hypertension

Both quality of life (QoL) and caregiver burden are essential constructs in patients with pulmonary hypertension (PH) however; their relationship has never been investigated before. The aim of this study was to evaluate if there was any relationship between patients' QoL and caregiver burden. Patients with PH and their caregivers were included. Patients' age, sex, World Health Organization (WHO) functional class, systolic pulmonary arterial pressure (sPAP), and six-minute walk distances (6MWD) were recorded. Patients' QoL was assessed using emPHasis-10 and caregiver burden with the Zarit Caregiver Burden Scale. 72 patient-caregiver dyads were included. Caregiver burden was significantly correlated with the QoL(r = 0.39 p < .003), but was not correlated with other clinical parameters. Patients' QoL showed significant negative correlation with the 6MWD(r = -0.46 p < .005). There is a moderate correlation between QoL and caregiver burden. Clinical parameters influence QoL, but they do not affect caregiver burden.

Long-term outcomes in pulmonary arterial hypertension by functional class: a meta-analysis of randomized controlled trials and observational registries

Limited data about the long-term prognosis and response to therapy in pulmonary arterial hypertension patients with World Health Organization functional class I/II symptoms are available. PubMed and Embase were searched for publications of observational registries and randomized, controlled trials in pulmonary arterial hypertension patients published between January 2001 and January 2018. Eligible registries enrolled pulmonary arterial hypertension patients ≥18 years, N > 30, and reported survival by functional class. Randomized, controlled trial inclusion criteria were pulmonary arterial hypertension patients ≥18 years, ≥6 months of treatment, and morbidity, mortality, or time to worsening as end points reported by functional class. The primary outcomes were survival for registries and clinical event rates for randomized, controlled trials. Separate random effects models were calculated for registries and randomized, controlled trials. Four randomized, controlled trials (n = 2482) and 10 registries (n = 6580) were included. Registries enrolled 9%–47% functional class I/II patients (the vast majority being functional class II) with various pulmonary arterial hypertension etiologies. Survival rates for functional class I/II patients at one, two, and three years were 93% (95% confidence interval (CI): 91%–95%), 86% (95% CI: 82%–89%), and 78% (95% CI: 73%–83%), respectively. The hazard ratio for the treatment effect in randomized, controlled trials overall was 0.61 (95% CI: 0.51–0.74) and 0.60 (95% CI: 0.44–0.82) for functional class I/II patients and 0.62 (95% CI: 0.49–0.78) for functional class III/IV. The calculated risk of death of 22% within three years for functional class I/II patients underlines the need for careful assessment and optimal treatment of patients with functional class I/II disease. The randomized, controlled trial analysis demonstrates that current medical therapies have a beneficial treatment effect in this population.

Novel composite clinical endpoints and risk scores used in clinical trials in pulmonary arterial hypertension

This manuscript on endpoints incorporates the broad experience of members of Pulmonary Vascular Research Institute’s Innovative Drug Development Initiative as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. It reviews our current understanding of endpoints used in phase 2 and 3 trials for pulmonary hypertension and discusses in detail the value of newer approaches. These include the roles of composite endpoints and how these can be developed and validated. The newer concept of risk analysis is also discussed, including how such risk scores might be utilised as endpoints in clinical trials.

Management of Pulmonary Arterial Hypertension

Purpose of Review

This review focuses on the therapeutic management and individualized approach to Group 1 pulmonary arterial hypertension (PAH), utilizing Food and Drug Administration-approved PAH-specific therapies and various interventional and surgical options for PAH.

Recent Findings

The paradigm for the optimal management of PAH has shifted in recent years. Upfront combination therapy with an endothelin receptor antagonist and a phosphodiesterase 5 inhibitor is now widely accepted as standard of care. In addition, there is increasing emphasis on starting prostanoids early in order to delay time to clinical worsening. However, less is known regarding which prostanoid agent to initiate and the optimum time to do so. In order to facilitate shared decision-making, there is an increasing need for decision tools based on guidelines and collective clinical experiences to navigate between pharmacologic and interventional treatments, as well as explore innovative, therapeutic pathways for PAH.

Summary

The management of PAH has become increasingly complex. With a growing number of PAH-specific therapies, intimate knowledge of the therapeutics and the potential barriers to adherence are integral to providing optimal care for this high-risk patient population. While current PAH-specific therapies largely mediate their effects through pulmonary vasodilation, ongoing research efforts are focused on ways to disrupt the mechanisms leading to pulmonary vascular remodeling. By targeting aberrations identified in the metabolism and proliferative state of pulmonary vascular cells, novel PAH treatment pathways may be just on the horizon.

Right Atrial Pressure During Exercise Predicts Survival in Patients With Pulmonary Hypertension

Background We investigated changes in right atrial pressure (RAP) during exercise and their prognostic significance in patients assessed for pulmonary hypertension (PH). Methods and Results Consecutive right heart catheterization data, including RAP recorded during supine, stepwise cycle exercise in 270 patients evaluated for PH, were analyzed retrospectively and compared among groups of patients with PH (mean pulmonary artery pressure [mPAP] ≥25 mm Hg), exercise-induced PH (exPH; resting mPAP <25 mm Hg, exercise mPAP >30 mm Hg, and mPAP/cardiac output >3 Wood Units (WU)), and without PH (noPH). We investigated RAP changes during exercise and survival over a median (quartiles) observation period of 3.7 (2.8-5.6) years. In 152 patients with PH, 58 with exPH, and 60 with noPH, median (quartiles) resting RAP was 8 (6-11), 6 (4-8), and 6 (4-8) mm Hg (P<0.005 for noPH and exPH versus PH). Corresponding peak changes (95% CI) in RAP during exercise were 5 (4-6), 3 (2-4), and -1 (-2 to 0) mm Hg (noPH versus PH P<0.001, noPH versus exPH P=0.027). RAP increase during exercise correlated with mPAP/cardiac output increase (r=0.528, P<0.001). The risk of death or lung transplantation was higher in patients with exercise-induced RAP increase (hazard ratio, 4.24; 95% CI, 1.69-10.64; P=0.002) compared with patients with unaltered or decreasing RAP during exercise. Conclusions In patients evaluated for PH, RAP during exercise should not be assumed as constant. RAP increase during exercise, as observed in exPH and PH, reflects hemodynamic impairment and poor prognosis. Therefore, our data suggest that changes in RAP during exercise right heart catheterization are clinically important indexes of the cardiovascular function.

Portopulmonary Hypertension: From Bench to Bedside

Portopulmonary hypertension (PoPH) is defined as pulmonary arterial hypertension (PAH) associated with portal hypertension and is a subset of Group 1 pulmonary hypertension (PH). PoPH is a cause of significant morbidity and mortality in patients with portal hypertension with or without liver disease. Significant strides in elucidating the pathogenesis, effective screening algorithms, accurate diagnoses, and treatment options have been made in past 20 years. Survival of PoPH has remained poor compared to IPAH and other forms of PAH. Recently, the first randomized controlled trial was done in this patient population and showed promising results with PAH specific therapy. Despite positive effects on hemodynamics and functional outcomes, it is unclear whether PAH specific therapy has a beneficial effect on long term survival or transplant outcomes. In this review, we will discuss the epidemiology, pathophysiology, clinical and hemodynamic characteristics of PoPH. Additionally, this review will highlight the lacunae in our current management strategy, challenges faced and will provide direction to potentially useful futuristic management strategies.

Prognostic Impact of the Pulmonary Artery Pulsatility Index in Patients with Chronic Heart Failure and Severe Mitral Regurgitation Undergoing Percutaneous Edge-to-Edge Repair

BACKGROUND

Pulmonary artery (PA) pulsatility index (PAPi), calculated as (PA systolic pressure - PA diastolic pressure)/right atrial pressure, emerged as a novel predictor of right ventricular failure in patients with acute inferior myocardial infarction, advanced heart failure, and severe pulmonary hypertension. However, the prognostic utility of PAPi in transcatheter mitral valve repair (TMVR) using the MitraClip® system has never been tested.

OBJECTIVE

To assess the prognostic impact of PAPi in patients with severe functional mitral regurgitation (MR) and chronic heart failure (CHF) undergoing TMVR.

METHODS

Consecutive patients with severe functional MR (grade 3+ or 4+) and CHF who underwent successful TMVR (MR ≤2+ at discharge) were enrolled and divided into 3 groups according to PAPi (A: low PAPi ≤2.2; B: intermediate PAPi 2.21-3.99; C: high PAPi ≥4.0). The primary endpoint was a composite of all-cause mortality and rehospitalization due to CHF during a mean follow-up period of 16 ± 4 months. The impact of PAPi on prognosis was assessed by a receiver-operating characteristic (ROC) analysis and a multivariable Cox proportional hazard regression analysis investigating independent predictors for outcome.

RESULTS

78 patients (A: n = 27, B: n = 28, C: n = 23) at high operative risk (logistic EuroSCORE [European System for Cardiac Operative Risk Evaluation] 18.8 vs. 21.5 vs. 20.6%; nonsignificant) were enrolled. Mean PAPi was 1.6 ± 0.41 vs. 2.9 ± 0.53 vs. 6.8 ± 3.5; p < 0.001). Patients with low PAPi showed significantly higher rates of early rehospitalization for heart failure at the 30-day follow-up (14.9 vs. 7.1 vs. 4.3%; p = 0.04). In the long term, a significantly lower event-free survival for the combined primary endpoint was observed in the low PAPi group (44.4 vs. 25.0 vs. 20.3%; log-rank p = 0.016). ROC curve analysis revealed that optimal sensitivity and specificity were achieved using a PAPi cutoff of 2.46 (sensitivity 83%, specificity 78.3%, area under the curve 0.82 [0.64-0.99]; p = 0.01). In Cox regression analysis, PAPi ≤2.46 was an independent predictor for the combined primary endpoint (hazard ratio 2.85; 95% confidence interval 1.15-7.04; p = 0.023).

CONCLUSIONS

PAPi is strongly associated with clinical outcome among patients with CHF and functional MR undergoing TMVR. A PAPi value ≤2.46 predicts a worse prognosis independent of other important clinical, echocardiographic, and hemodynamic factors. Therefore, PAPi may serve as a new parameter to improve patient selection for TMVR.

Chronic inflammation within the vascular wall in pulmonary arterial hypertension: more than a spectator

This review seeks to provide an update of preclinical findings and available clinical data on the chronic persistent inflammation and its direct role on the pulmonary arterial hypertension (PAH) progression. We reviewed the different mechanisms by which the inflammatory and immune pathways contribute to the structural and functional changes occurring in the three vascular compartments: the tunica intima, tunica media, and tunica adventitia. We also discussed how these inflammatory mediator changes may serve as a biomarker of the PAH progression and summarize unanswered questions and opportunities for future studies in this area.

Current clinical utilization of risk assessment tools in pulmonary arterial hypertension: a descriptive survey of facilitation strategies, patterns, and barriers to use in the United States

Practice guidelines suggest that treatment decisions in pulmonary arterial hypertension be informed by periodic assessment of patients' clinical risk. Several tools, well validated for risk discrimination, such as the Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management calculator, were developed to assess pulmonary arterial hypertension patients' risk of death based on multiple parameters, including functional class, hemodynamics, biomarkers, comorbidities, and exercise capacity. Using an online survey, we investigated the use of risk assessment tools by pulmonary hypertension healthcare providers in the United States. Of 121 survey respondents who make treatment decisions, 59% reported using risk assessment tools. The use of these tools was lower for non-physicians (48% vs. 65% physicians) and for practitioners at centers with 1 to 100 pulmonary arterial hypertension patients compared with centers with >100 patients (47% vs. 64%). Risk was most frequently assessed by decision makers at the time of diagnosis (cited by 54%) and at the time of worsening symptoms (cited by 42%), suggesting that use of pulmonary arterial hypertension risk assessment tools remains low. In our survey, non-physicians compared with physicians cited two major barriers to increased tool use: lack of education and training (20% vs. 4%) and lack of clarity on the best tool to use (30% vs. 18%). Information technology tools, such as electronic medical record integration and web or phone-based risk calculating applications, were cited most frequently as ways to increase the use of risk assessment tools.

Long-term changes of exercise hemodynamics and physical capacity in chronic thromboembolic pulmonary hypertension after pulmonary thromboendarterectomy

BACKGROUND

A substantial number of chronic thromboembolic pulmonary hypertension (CTEPH) patients experience dyspnea on exertion and limited exercise capacity despite surgically successful pulmonary endarterectomy (PEA). We sought to prospectively evaluate resting and peak exercise hemodynamics before, 3 and 12 months after PEA in consecutive CTEPH-patients and correlate it to physical functional capacity.

METHODS AND RESULTS

Twenty consecutive CTEPH-patients were examined. Twelve months after PEA, 75% of patients with severely increased pre-PEA mean pulmonary arterial pressure (mPAP) at rest had normal or mildly increased mPAP. However, mPAP reduction was less pronounced during exercise where only 45% had normal or mildly increased mPAP at 12 months. Hemodynamic changes during exercise were tested using the pressure-flow relationship (i.e. mPAP/cardiac output (CO) slope). The average mPAP/CO slope was 7.5 ± 4.2 mm Hg/L/min preoperatively and 3.9 ± 3.0 mm Hg/L/min at 12 months (p < .005). CO reserve (CO increase from rest to peak exercise) was increased (5.7 ± 2.9 L/min) 12 months after PEA compared with pre-PEA (2.5 ± 1.8 L/min), p < .0001. However, 12 months after PEA, the CO reserve was only 49% of that of healthy controls, p < .0001. Changes in cardiac output (∆CO), calculated as the difference between CO before PEA and 12 months later, were significantly correlated with six-minute-walk-test and peak oxygen uptake (VO2), both at rest and peak exercise.

CONCLUSION

Invasive exercise hemodynamic examination in CTEPH-patients demonstrates that after otherwise successful PEA surgery, >50% of patients have a significant increase in exercise mPAP, and the CO reserve remains compromised 12 months after PEA. Improvement in physical capacity is correlated with ∆CO.

Renin-Angiotensin-Aldosterone System Inhibitor Use and Mortality in Pulmonary Hypertension: Insights From the Veterans Affairs Clinical Assessment Reporting and Tracking Database

BACKGROUND

The renin-angiotensin-aldosterone system (RAAS) contributes to pulmonary hypertension (PH) pathogenesis. Although animal data suggest that RAAS inhibition attenuates PH, it is unknown if RAAS inhibition is beneficial in PH patients.

RESEARCH QUESTION

Is RAAS inhibitor use associated with lower mortality in a large cohort of patients with hemodynamically confirmed PH?

STUDY DESIGN AND METHODS

We used the Department of Veterans Affairs Clinical Assessment Reporting and Tracking Database to study retrospectively relationships between RAAS inhibitors (angiotensin converting enzyme inhibitors [ACEIs], angiotensin receptor blockers [ARBs], and aldosterone antagonists [AAs]) and mortality in 24,221 patients with hemodynamically confirmed PH. We evaluated relationships in the full and in propensity-matched cohorts. Analyses were adjusted for demographics, socioeconomic status, comorbidities, disease severity, and comedication use in staged models.

RESULTS

ACEI and ARB use was associated with improved survival in unadjusted Kaplan-Meier survival analyses in the full cohort and the propensity-matched cohort. This relationship was insensitive to adjustment, independent of pulmonary artery wedge pressure, and also was observed in a cohort restricted to individuals with precapillary PH. AA use was associated with worse survival in unadjusted Kaplan-Meier survival analyses in the full cohort; however, AA use was associated less robustly with mortality in the propensity-matched cohort and was not associated with worse survival after adjustment for disease severity, indicating that AAs in real-world practice are used preferentially in sicker patients and that the unadjusted association with increased mortality may be an artifice of confounding by indication of severity.

INTERPRETATION

ACEI and ARB use is associated with lower mortality in veterans with PH. AA use is a marker of disease severity in PH. ACEIs and ARBs may represent a novel treatment strategy for diverse PH phenotypes.

Molecular mechanisms of right ventricular dysfunction in pulmonary arterial hypertension: focus on the coronary vasculature, sex hormones, and glucose/lipid metabolism

Pulmonary arterial hypertension (PAH) is a rare, life-threatening condition characterized by dysregulated metabolism, pulmonary vascular remodeling, and loss of pulmonary vascular cross-sectional area due to a variety of etiologies. Right ventricular (RV) dysfunction in PAH is a critical mediator of both long-term morbidity and mortality. While combinatory oral pharmacotherapy and/or intravenous prostacyclin aimed at decreasing pulmonary vascular resistance (PVR) have improved clinical outcomes, there are currently no treatments that directly address RV failure in PAH. This is, in part, due to the incomplete understanding of the pathogenesis of RV dysfunction in PAH. The purpose of this review is to discuss the current understanding of key molecular mechanisms that cause, contribute and/or sustain RV dysfunction, with a special focus on pathways that either have led to or have the potential to lead to clinical therapeutic intervention. Specifically, this review discusses the mechanisms by which vessel loss and dysfunctional angiogenesis, sex hormones, and metabolic derangements in PAH directly contribute to RV dysfunction. Finally, this review discusses limitations and future areas of investigation that may lead to novel understanding and therapeutic interventions for RV dysfunction in PAH.

Left ventricular ischemia in pre-capillary pulmonary hypertension: a cardiovascular magnetic resonance study

Background

Prognosis in pulmonary arterial hypertension (PAH) is largely dependent on right ventricular (RV) function. However, recent studies have suggested the presence of left ventricular (LV) dysfunction in PAH patients. The potential role of LV ischemia, as a contributor to progressive LV dysfunction, has not been systematically studied in PAH. We aim to assess the presence and extent of LV myocardial ischemia in patients with known PH and without obstructive coronary artery disease (CAD), using oxygen-sensitive (OS) cardiovascular magnetic resonance (CMR) and stress/rest CMR T1 mapping.

Methods

We prospectively recruited 28 patients with right heart catheter-proven PH and no significant CAD, 8 patients with known CAD and 11 normal age-matched controls (NC). OS-CMR images were acquired using a T2* sequence and T1 maps were acquired using Shortened Modified Look-Locker Inversion recovery (ShMOLLI) at rest and adenosine-induced stress vasodilatation; ΔOS-CMR signal intensity (SI) index (stress/rest SI) and ΔT1 reactivity (stress-rest/rest T1 mapping) were calculated.

Results

Global LV ΔOS SI index was significantly lower in PH patients compared with controls (11.1%±6.7% vs. 20.5%±10.5%, P=0.016), as was ΔT1 reactivity (5.2%±4.5% vs. 8.0%±2.9%, P=0.047). The ischemic segments of CAD patients had comparable ΔOS SI (10.3%±6.4% vs. 11.1%±6.7%, P=0.773) to PH patients, but lower ΔT1 reactivity (1.1%±4.2% vs. 5.2%±4.5%, P=0.036).

Conclusions

Decreased OS-CMR SI and T1 reactivity signify the presence of impaired myocardial oxygenation and vasodilatory response in PH patients. Given their unobstructed epicardial coronary arteries, this is likely secondary to coronary microvascular dysfunction (CMD).

Prevalence and clinical features of bone morphogenetic protein receptor type 2 mutation in Korean idiopathic pulmonary arterial hypertension patients: The PILGRIM explorative cohort

Background

Pulmonary arterial hypertension (PAH) is a progressive chronic disease with poor outcomes. One reason for poor prognosis is the lack of understanding regarding individual variability in response to treatment. Idiopathic PAH (IPAH) patients with bone morphogenetic protein receptor type 2 (BMPR2) mutations have distinct phenotypes that are crucial for individualized therapy but evidence regarding their prevalence and clinical features in the Korean population is lacking. Therefore, the present study aimed to screen Korean IPAH patients for BMPR2 mutations and analyze their clinical phenotypes.

Methods

We enrolled 73 unrelated IPAH patients for BMPR2 mutation screening between March 2010 to November 2015 from 11 hospitals in Korea. Thirty-three lineal family members from 6 families of BMPR2 mutation carriers were also screened.

Results

Among 73 patients, 16 (22%) had BMPR2 mutations. Mutation carriers were younger (27 vs. 47 years; p = 0.02) and had a higher mean pulmonary arterial pressure (mPAP) than non-carriers (64 vs. 51 mmHg; p<0.05). Of the 16 individuals with mutations, 5 deletion, 2 splice-site, 6 nonsense, and 3 missense mutations were found, among which, 9 were newly identified mutation types. Patients less than 30 years old had more BMPR2 mutations (44 vs. 14%; p = 0.04) and a higher mPAP (64 vs. 50 mmHg; p = 0.04) compared with those equaled to or over 30 years old. There were no differences in hemodynamic profiles or the proportion of BMPR2 mutation carriers between groups according to sex.

Conclusion

The prevalence of BMPR2 mutations in Korean IPAH patients was 22%. Mutation carriers were younger and had a poorer hemodynamic profile compared with the non-carriers.

Clinical trial registration

Clinicaltrials.gov NCT01054105

Association between right atrial area measured by echocardiography and prognosis among pulmonary arterial hypertension: a systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to evaluate the association between enlarged right atrial area (RAA), as measured by echocardiography, and prognosis of patients with pulmonary arterial hypertension (PAH).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

To identify potential publications, a comprehensive literature search through MEDLINE, the Cochrane database and the Embase database was performed up to December 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included if they reported Cox regression based-HRs with 95% CIs for all-cause mortality or composite endpoint consisting of death and PAH-related events for echocardiography measurements of the RAA or the right atrial area index (RAAI) in patients with PAH.

DATA EXTRACTION AND SYNTHESIS

The unadjusted HR with 95% CI was extracted for the final pooled analysis. A random-effects model was used to determine the value of RAA/RAAI in the prognosis of patients with PAH. The data heterogeneity among the studies was estimated by the I² statistic and the Cochran Q-statistic.

RESULTS

Twelve studies with a total of 1085 patients with PAH were finally included in the meta-analysis. These studies had a mean follow-up time ranging from 9.2 months to 5.0 years. Their findings showed that patients with PAH with enlarged RAA/RAAI were associated with poor prognosis. The risk of all-cause mortality in patients with PAH was found to statistically increase by 50% for every 5-unit increase in RAA/RAAI (HR 1.50, 95% CI 1.28 to 1.75, p<0.001). Similarly, the risk of the composite endpoint also significantly increased by 53% for every 5-unit increase in RAA/RAAI (HR 1.53, 95% CI 1.23 to 1.89, p<0.001). Subgroup analyses in which the patients were stratified by RAA and RAAI were consistent with the main results.

CONCLUSION

The meta-analysis suggested that enlarged RAA/RAAI were associated with increased risk of poor prognosis in patients with PAH.

Implementation of a systematic comprehensive geriatric assessment for elderly patients suspected of pulmonary hypertension

BACKGROUND

The phenotype of patients seen for a suspicion of pulmonary hypertension has changed, with an increasing age and frequency of comorbidities. Selection of elderly patients, in whom a classical work-up is mandatory, is challenging. Comprehensive geriatric assessment (CGA) has modified the management of elderly patients with cancer. Pulmonary hypertension (PH) shares with cancer a functional impact and may evolve rapidly, depending on the group of PH. We assessed the impact of a systematic CGA in patients over 70 years old referred for a suspicion of PH.

METHODS

A standardised CGA was performed on every patient older than 70 years old, referred for a PH suspicion, before considering invasive tests for diagnosis and treatment, between July 2014 and May 2019. Our primary aim was to describe the impact of CGA on the decision to stop or pursue the recommended diagnostic work-up for PH.

RESULTS

Among the thirty-one patients evaluated [mean age 81,5 (72-91) years], a negative CGA leads to stop the diagnostic work-up in eleven patients. Among the nineteen remaining patients, sixteen had confirmed PH, with half being chronic thromboembolic pulmonary hypertension.

CONCLUSIONS

Our study indicates that comprehensive geriatric assessment could be an excellent first screen for elderly patients referred for a PH suspicion. Involving a geriatric physician stopped the investigations in one third of patients. In patients with a favourable CGA, PH was confirmed in most of the cases, with chronic thromboembolic pulmonary hypertension being the first cause of PH.

Prognostic importance of Kidney, Heart and Interstitial lung diseases (KHI triad) in PH: A machine learning study

BACKGROUND

Pulmonary hypertension (PH) is a heterogeneous, severe and progressive disease with an impact on quality of life and life-expectancy despite specific therapies.

AIMS

(i) to compare prognosis significance of each PH subgroup in a cohort from a referral center, (ii) to identify phenotypically distinct high-risk PH patient using machine learning.

METHODS

Patients with PH were included from 2002 to 2019 and routinely followed-up. We collected clinical, laboratory, imaging and hemodynamic variables. Four-year survival rate of each subgroups was then compared. Next, phenotypic domains were imputed with 5 eigenvectors for missing values and filtered if the Pearson correlation coefficient was>0.6. Thereafter, agglomerative hierarchical clustering was used for grouping phenotypic variables and patients: a heat map was generated and participants were separated using Penalized Model-Based Clustering. P<0.05 was considered significant.

RESULTS

328 patients were prospectively included (mean age 63±18 yo, 46% male). PH secondary to left heart disease (PH-LHD) and lung disease (PH-LD) had a significantly increased mortality compared to pulmonary arterial hypertension (PAH) patients: HR=2.43, 95%CI=(1.24-4.73) and 2.95, 95%CI=(1.43-6.07) respectively. 25 phenotypic domains were pinpointed and 3 phenogroups identified. Phenogroup 3 had a significantly increased mortality (log-rank P=0.046) compared to the others and was remarkable for predominant pulmonary disease in older male, accumulating cardiovascular risk factors, and simultaneous three major comorbidities: coronary artery disease, chronic kidney disease and interstitial lung disease.

CONCLUSION

PH-LHD and PH-LD has 2-fold and 3-fold increase in mortality, respectively compared with PAH. PH patients with simultaneous kidney-cardiac-pulmonary comorbidities were identified as having high-risk of mortality. Specific targeted therapy in this phenogroup should be prospectively evaluated.

Exercise Hemodynamics in the Prognosis of Patients with Pulmonary Arterial Hypertension

BACKGROUND

Assessment of prognosis is of major importance when deciding on a therapeutic strategy in patients with pulmonary arterial hypertension (PAH).

OBJECTIVES

The aim of this study was to investigate the prognostic value of pulmonary hemodynamics during exercise and changes during treatment in patients with PAH.

METHODS

Consecutive incident patients (n = 49) with PAH undergoing right heart catheterization at rest and during a constant workload cycle exercise in supine position were included. Predictors of survival were identified at baseline using Cox proportional hazard regression models in a univariate analysis unadjusted and adjusted for age and gender.

RESULTS

During a median follow-up period of 42 months, 13 (27%) of the 49 patients studied died. Two predictors of death were found: rest-to-exercise changes in heart rate and systolic pulmonary artery pressure. Adjusted hazard ratios were 0.92 (95% CI 0.86-0.99) and 0.93 (95% CI 0.88-0.99), respectively. These 2 variables were correlated with each other (r = 0.55, p < 0.001).

CONCLUSIONS

Rest-to-exercise changes in heart rate and systolic pulmonary artery pressure measured at diagnosis are predictors of survival in patients with PAH. These measurements taken from an exercise test reflect right ventricular function.

Sex Differences in Portopulmonary Hypertension

BACKGROUND

Portopulmonary hypertension (POPH), pulmonary arterial hypertension that develops in the setting of portal hypertension, can lead to right-sided heart failure and death. Being female is a known risk factor for POPH, but little is known about the effect of sex on clinical manifestations, hemodynamics, treatment response, and survival.

RESEARCH QUESTION

We sought to characterize sex differences in clinical characteristics, pulmonary hemodynamics, treatment response, and survival in patients with POPH.

STUDY DESIGN AND METHODS

We performed a retrospective cohort study of adult candidates for liver transplant (LT) who had POPH within the Organ Procurement and Transplantation Network database. Females and males were compared. Multivariate regression was performed to assess the association between sex and pulmonary vascular resistance (PVR) and survival. Patients were also stratified by age (50 years) to determine how age modifies the relationship between sex and hemodynamics and survival.

RESULTS

We included 190 adults (103 male, 87 female). Compared with men, women had a lower model for end-stage liver disease (MELD) score (12.1± 4.2 vs 13.8 ± 4.9; P = .01) and were more likely to have autoimmune liver disease. Women had a higher baseline PVR (610.6 ± 366.6 vs 461.0 ± 185.3 dynes-s-cm^-5; P < .001) and posttreatment PVR (244.6 ± 119.5 vs 202.0 ± 87.7 dynes-s-cm^-5; P = .008) and a greater treatment response (ΔPVR) (-359.3 ± 381.9 vs -260.2 ± 177.3 dynes-s-cm^-5; P = .03). In multivariate analysis, female sex (or gender) remained associated with a higher baseline PVR (P = .008). Women and men had overall similar survival (P > .05). When patients were stratified by age, being female was independently associated with worse waiting list survival after adjusting for MELD and PVR in younger patients (HR, 6.61; 95% CI, 1.25-35.08; P = .03) but not in older patients.

INTERPRETATION

Compared with male candidates, female candidates for LT who had POPH had a higher PVR and lower MELD score and were more likely to have autoimmune liver disease. Women and men had similar overall survival, but female sex (or gender) was associated with worse survival in younger patients.

Supra-coronary aortic banding improves right ventricular function in experimental pulmonary arterial hypertension in rats by increasing systolic right coronary artery perfusion

AIM

Pulmonary arterial hypertension (PAH) results in right ventricular (RV) dysfunction owing, in part, to RV ischemia. The relative contribution of RV microvascular rarefaction vs reduced right coronary artery perfusion pressure (RCA-PP) to RV ischemia remains unknown. We hypothesize that increasing RCA-PP improves RV function in PAH by increasing RV systolic perfusion.

METHODS

Supra-coronary aortic banding (SAB) or sham surgery was performed on male Sprague-Dawley rats. Seven to ten days later, rats received either monocrotaline (MCT; 60 mg/kg) or saline. After 1 month, echocardiography, cardiac catheterization, ^99m Tc-sestamibi single-photon emission computed tomography (SPECT) and microsphere infusion studies were performed. The RV was harvested for measurement of hypertrophy (RVH), fibrosis and immunoblotting, and the lung was harvested for pulmonary artery (PA) histology.

RESULTS

Supra-coronary aortic banding increased systolic pressures in proximal aorta and systolic RCA-PP in SAB + MCT vs MCT rats (114 ± 12 vs 5 ± 9 mm Hg), without altering diastolic RCA-PP. SAB + MCT rats had improved RV function vs MCT rats, evident from their significantly increased cardiac output (CO), RV free wall (RVFW) thickening, tricuspid annular plane systolic excursion (TAPSE) and RV-PA coupling indices. RV-PA coupling indices and CO correlated directly with systolic RCA-PP. RV perfusion was increased in SAB + MCT vs MCT rats and correlated well with CO; whereas microvascular rarefaction was unaltered. SAB + MCT rats had less RVH and fibrosis and lower PA pressures vs MCT rats. SAB + MCT rats had significantly lower RV pyruvate kinase muscle isoform 2/1 ratios than MCT rats, consistent with restoration of oxidative metabolism.

CONCLUSION

A SAB-induced increase in systolic RCA-PP improves RV perfusion and function in MCT rats. Maintaining systolic RCA perfusion can preserve RV function in PAH.

Beyond the genome: challenges and potential for epigenetics-driven therapeutic approaches in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease of the cardiopulmonary system caused by the narrowing of the pulmonary arteries, leading to increased vascular resistance and pressure. This leads to right ventricle remodeling, dysfunction, and eventually, death. While conventional therapies have largely focused on targeting vasodilation, other pathological features of PAH including aberrant inflammation, mitochondrial dynamics, cell proliferation, and migration have not been well explored. Thus, despite some recent improvements in PAH treatment, the life expectancy and quality of life for patients with PAH remains poor. Showing many similarities to cancers, PAH is characterized by increased pulmonary arterial smooth muscle cell proliferation, decreased apoptotic signaling pathways, and changes in metabolism. The recent successes of therapies targeting epigenetic modifiers for the treatment of cancer has prompted epigenetic research in PAH, revealing many new potential therapeutic targets. In this minireview we discuss the emergence of epigenetic dysregulation in PAH and highlight epigenetic-targeting compounds that may be effective for the treatment of PAH.

Identification and Validation of Key Genes Associated With Systemic Sclerosis-Related Pulmonary Hypertension

Systemic sclerosis-associated with pulmonary arterial hypertension (SSc-PAH) is still a major cause of SSc related deaths. Early diagnosis and prompt treatment are crucial to reduce the mortality of patients with SSc-PAH. To screen the candidate biomarkers and potential therapeutic targets for SSc-PAH, we analyzed the data set (GSE33463 and GSE19617) for confirming key genes in peripheral blood mononuclear cells from SSc-PAH patients. A total of 105 SSc patients from gene expression omnibus (GEO) were included as discovery cohort (n = 69) and duplication cohort (n = 36) for screening hub genes by weighted gene co-expression network analysis (WGCNA). Furthermore, an independent validation cohort (n = 40), including healthy controls, SSc and SSc-PAH patients, was used for further validation by quantitative real-time polymerase chain reaction. The results showed that four key genes, including IFIT2, IFIT3, RSAD2, and PARP14, may serve as potential biomarkers in SSc-PAH. Also, they could be independent risk factors for SSc-PAH. In conclusion, the four key genes can be expected to become the potential therapeutic targets and early biomarkers for accurate therapy and diagnosis of SSc-PAH in the future, which also provides promising insights into the pathogenesis of SSc-PAH at the molecular level.

Identification of Long Noncoding RNA H19 as a New Biomarker and Therapeutic Target in Right Ventricular Failure in Pulmonary Arterial Hypertension

BACKGROUND

Right ventricular (RV) function is the major determinant for both functional capacity and survival in patients with pulmonary arterial hypertension (PAH). Despite the recognized clinical importance of preserving RV function, the subcellular mechanisms that govern the transition from a compensated to a decompensated state remain poorly understood and as a consequence there are no clinically established treatments for RV failure and a paucity of clinically useful biomarkers. Accumulating evidence indicates that long noncoding RNAs are powerful regulators of cardiac development and disease. Nonetheless, their implication in adverse RV remodeling in PAH is unknown.

METHODS

Expression of the long noncoding RNA H19 was assessed by quantitative PCR in plasma and RV from patients categorized as control RV, compensated RV or decompensated RV based on clinical history and cardiac index. The impact of H19 suppression using GapmeR was explored in 2 rat models mimicking RV failure, namely the monocrotaline and pulmonary artery banding. Echocardiographic, hemodynamic, histological, and biochemical analyses were conducted. In vitro gain- and loss-of-function experiments were performed in rat cardiomyocytes.

RESULTS

We demonstrated that H19 is upregulated in decompensated RV from PAH patients and correlates with RV hypertrophy and fibrosis. Similar findings were observed in monocrotaline and pulmonary artery banding rats. We found that silencing H19 limits pathological RV hypertrophy, fibrosis and capillary rarefaction, thus preserving RV function in monocrotaline and pulmonary artery banding rats without affecting pulmonary vascular remodeling. This cardioprotective effect was accompanied by E2F transcription factor 1-mediated upregulation of enhancer of zeste homolog 2. In vitro, knockdown of H19 suppressed cardiomyocyte hypertrophy induced by phenylephrine, while its overexpression has the opposite effect. Finally, we demonstrated that circulating H19 levels in plasma discriminate PAH patients from controls, correlate with RV function and predict long-term survival in 2 independent idiopathic PAH cohorts. Moreover, H19 levels delineate subgroups of patients with differentiated prognosis when combined with the NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels or the risk score proposed by both REVEAL (Registry to Evaluate Early and Long-Term PAH Disease Management) and the 2015 European Pulmonary Hypertension Guidelines.

CONCLUSIONS

Our findings identify H19 as a new therapeutic target to impede the development of maladaptive RV remodeling and a promising biomarker of PAH severity and prognosis.

Angiotensin converting enzyme 2 and angiotensin (1-7) axis in pulmonary arterial hypertension

BACKGROUND

In animal models of pulmonary arterial hypertension (PAH), angiotensin-converting enzyme (ACE)2 and angiotensin (Ang)-(1-7) have been shown to have vasodilatory, antiproliferative, antifibrotic and antihypertrophic properties. However, the status and role of the ACE2-Ang(1-7) axis in human PAH is incompletely understood.

METHODS

We studied 85 patients with a diagnosis of PAH of distinct aetiologies. 55 healthy blood donors paired for age and sex served as controls. Blood samples were obtained from the pulmonary artery in patients with PAH during right heart catheterisation. Peripheral blood was obtained for both groups. Ang(1-7) and -II were measured using zone capillary electrophoresis. Aldosterone, Ang(1-9), AngA and ACE2 were measured using ELISA, and ACE2 activity was determined enzymatically.

RESULTS

Of the 85 patients, 47 had idiopathic PAH, 25 had PAH associated with congenital heart disease and 13 had PAH associated with collagen vascular disease. Compared to controls, patients with PAH had a higher concentration of AngII (median 1.03, interquartile range 0.72-1.88 pmol·mL^-1 versus 0.19, 0.10-0.37 pmol·mL^-1; p<0.001) and of aldosterone (88.7, 58.7-132 ng·dL^-1 versus 12.9, 9.55-19.9 ng·dL^-1; p<0.001). Conversely, PAH patients had a lower concentration of Ang(1-7) than controls (0.69, 0.474-0.91 pmol·mL^-1 versus 4.07, 2.82-6.73 pmol·mL^-1; p<0.001), and a lower concentration of Ang(1-9) and AngA. Similarly, the ACE2 concentration was higher than in controls (8.7, 5.35-13.2 ng·mL^-1 versus 4.53, 1.47-14.3 ng·mL^-1; p=0.011), whereas the ACE2 activity was significantly reduced (1.88, 1.08-2.81 nmol·mL^-1 versus 5.97, 3.1-17.8 nmol·mL^-1; p<0.001). No significant differences were found among the three different aetiological forms of PAH.

CONCLUSIONS

The AngII-ACE2-Ang(1-7) axis appears to be altered in human PAH and we propose that this imbalance, in favour of AngII, plays a role in the pathogenesis of the severe PAH. Further mechanistic studies are warranted.

Effectiveness and safety of endothelin receptor antagonists, alone and in combination therapy, in the pulmonary arterial hypertension-connective tissue disease subtype: A systematic review and meta-analysis

INTRODUCTION

There is limited information regarding the effectiveness of endothelin receptor antagonists (ERA) in patients with connective tissue disease-pulmonary arterial hypertension (CTD-PAH), a condition that is characterized by poorer clinical outcomes compared to other PAH subtypes.

OBJECTIVE

To conduct a systematic review and meta-analysis of the effectiveness and safety of ERA in CTD-PAH.

METHODS

A literature search, using MEDLINE, COCHRANE, CINAHL and EMBASE databases was conducted, from inception to May 2019 to identify randomized control studies of ERA, as monotherapy or in combination with phosphodiesterase type 5 inhibitors (PDE5i), in CTD-PAH. A protocol was registered in PROSPERO (CRD42019136956). Efficacy outcomes, including the 6-minute walk distance (6MWD) and composite clinical failure endpoints (CFE), and safety outcomes were evaluated.

RESULTS

A total of 13 studies, including 784 CTD-PAH participants, were identified. ERA, as monotherapy, did not reduce the risk of CFE compared to placebo (odds ratio [OR] 0.77, 95% CI 0.50-1.19, P = .25). By contrast, combination therapy (ERA + PDE5i) significantly reduced the risk of developing CFE vs monotherapy (OR 0.54, 95% CI 0.32-0.90, P = .02). 6MWD did not improve when comparing monotherapy vs placebo (+17.41 m; 95% CI -19.83-54.66) P = .36) or combination therapy vs monotherapy (+13.17 m; 95% CI -16.44-42.78, P = .38). ERA-related adverse events rates in CTD-PAH and general PAH cohorts were comparable.

CONCLUSIONS

ERA, when used in combination with PDE5is, are associated with reduced risk of CFE, but no significant changes in 6MWD, in CTD-PAH. This warrants further studies investigating early combination therapy as a standard of care in this group.

Efficacy and safety of riociguat in combination therapy for patients with pulmonary arterial hypertension (PATENT studies)

Many patients with pulmonary arterial hypertension do not achieve treatment goals with monotherapy, and therefore combination therapy is becoming the standard of care. The soluble guanylate cyclase stimulator riociguat is licensed for the treatment of pulmonary arterial hypertension; here we present findings from patients who were receiving combined riociguat plus endothelin receptor antagonists or non-intravenous prostanoids in the randomized, placebo-controlled PATENT-1 study and its open-label extension (PATENT-2). Moreover, we include new data from patients receiving early sequential combination therapy (three to six months of endothelin receptor antagonist treatment) or long-term background endothelin receptor antagonist therapy (>6 months). Patients were randomized to riociguat 2.5 mg–maximum (N = 131 pretreated patients) and placebo (N = 60 pretreated patients). Riociguat improved 6-min walking distance (PATENT-1 primary endpoint), functional capacity, and hemodynamics after 12 weeks in pretreated patients. The placebo-corrected changes in 6-min walking distance were +24 m in endothelin receptor antagonist-pretreated patients and +106 m in the small group of prostanoid-pretreated patients. In the early sequential combination and long-term background endothelin receptor antagonist groups, the placebo-corrected changes in 6-min walking distance were +65 m (95% CI: 17 to 113 m) and +13 m (95% CI: –8 to 33 m), respectively. In conclusion, these data suggest that early sequential combination of an endothelin receptor antagonist plus riociguat is a feasible treatment option. Both early sequential therapy and long-term background endothelin receptor antagonist plus riociguat were well tolerated in the PATENT studies.

Increased levels of platelet-derived microparticles in pulmonary hypertension

INTRODUCTION

Thrombosis and coagulation abnormalities are thought to be involved in disease progression of pulmonary hypertension. Platelet-derived microparticles (PDMP) are released from platelets following stimulation and have recently been demonstrated to play an important role in pathogenesis of various diseases. This study aimed to evaluate PDMP levels in patients with pulmonary hypertension.

MATERIALS AND METHODS

Our cross-sectional study enrolled a total of 113 participants including 73 patients with pulmonary hypertension and 40 participants to serve as a control group. PDMP levels were measured using a PDMP ELISA kit, which detects glycoproteins CD42a and CD42b. Clinical parameters, including exercise capacity and hemodynamic parameters, were collected, and the relationship to PDMP levels were evaluated.

RESULTS

PDMP levels were significantly higher in patients than in participants in the control group (23.2 ± 39.4 U/mL and 7.8 ± 3.6 U/mL, respectively, P < 0.05). PDMP levels in patients with chronic thromboembolic pulmonary hypertension were correlated with right atrial pressure and cardiac index. PDMP levels were higher in male patients with idiopathic pulmonary arterial hypertension. Furthermore, patients administered a higher dose of epoprostenol had a tendency for lower PDMP levels.

CONCLUSIONS

The data suggest that PDMP levels are increased in patients with pulmonary hypertension. Further study is needed to understand the mechanism and impact of PDMP on disease progression.

Pulmonary Hypertension Phenotypes in Systemic Sclerosis: The Right Diagnosis for the Right Treatment

Systemic sclerosis is an auto-immune disease characterized by skin involvement that often affects multiple organ systems. Pulmonary hypertension is a common finding that can significantly impact prognosis. Molecular pathophysiological mechanisms underlying pulmonary hypertension in systemic sclerosis can be extremely heterogeneous, leading to distinct clinical phenotypes. In addition, different causes of pulmonary hypertension may overlap within the same patient. Since pulmonary hypertension treatment is very different for each phenotype, it is fundamental to perform an adequate diagnostic work-up to properly and promptly identify the prevalent mechanism underlying pulmonary hypertension in order to start the right therapies. When pulmonary hypertension is caused by a primary vasculopathy of the small pulmonary arteries, treatment with pulmonary vasodilators, often in an initial double-combination regimen, is indicated, aimed at reducing the mortality risk profile. In this review, we describe the different clinical phenotypes of pulmonary hypertension in the scleroderma population and discuss the utility of clinical tools to identify the presence of pulmonary vascular disease. Furthermore, we focus on systemic sclerosis-associated pulmonary arterial hypertension, highlighting the advances in the knowledge of right ventricular dysfunction in this setting and the latest updates in terms of treatment with pulmonary vasodilator drugs.

Prognostic value of six-minute walk distance at a South American pulmonary hypertension referral center

Six-minute walk distance (6MWD) assessment is recommended for pulmonary arterial hypertension multidimensional risk stratification. However, current 6MWD cut-off values were mainly derived from North American and European pulmonary arterial hypertension registries. Therefore, it is unknown if such cut-off values broadly apply to other geographical populations. In this study, we aimed to identify 6MWD cut-off values for Brazilian pulmonary arterial hypertension patients and to contrast our findings to current international Pulmonary Hypertension guidelines recommendations. One-hundred four consecutive pulmonary arterial hypertension patients were allocated in groups according to their 6MWD, considering 50 m as a clinically relevant 6MWD difference. Next, patients were categorized into different 6MWD ranges based on similar survival rates in each group: < 250 m, 250–400 m, and >400 m. The study outcome was all-cause mortality and transplantation according to the 6MWD range. Survival was truncated at five years. Median follow-up period was 4.35 years (0.48–5.00). Survival rates at 1, 2, 3, and 5 years were 96%, 89%, 81%, and 73%, respectively. Cox analyses adjusted for age, sex, and pulmonary arterial hypertension etiology showed that 6MWD < 250 m and >400 m were associated with higher and lower risk of all-cause mortality and transplantation. According to Harrell's c-statistic, the prognostic discrimination of the 6MWD cut-off value identified by the current study was 0.70 while international Pulmonary Hypertension guidelines 6MWD cut-offs value was 0.61. In conclusion, our findings suggest that 6MWD geographical variations should be considered when assessing risk stratification in pulmonary arterial hypertension.

Identification of Differentially Expressed Genes Associated with Idiopathic Pulmonary Arterial Hypertension by Integrated Bioinformatics Approaches

Idiopathic pulmonary arterial hypertension (IPAH) is a fatal cardiovascular disease event with significant morbidity and mortality. However, its potential molecular mechanisms and potential key genes have not been totally evaluated. The gene expression profile of GSE33463, including 30 individuals diagnosed with IPAH and 41 normal controls, was downloaded from Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified using limma package in R. Gene Ontology (GO) annotation, the Kyoto Encyclopedia of Genes and Genomes (KEGG) were carried out to get further insight into the possible functions of the identified DEGs. Then, the protein-protein interaction (PPI) network of all DEGs was constructed. Nodes with higher degree centrality (≥10) were considered as hub proteins in the PPI network. Area under the curve (AUC) values obtained from the receiver operating characteristic (ROC) curve analysis was utilized to assess the diagnostic effectiveness of hub genes in discriminating IPAH from normal individuals. Sixty-nine DEGs were identified, including 41 upregulated and 28 downregulated DEGs. The GO enrichment analysis indicated that genes were significantly enriched in oxygen carrier activity, oxygen binding, heme binding, molecular carrier activity, and antioxidant activity. KEGG pathway enrichment showed that genes were mainly involved in cytokine and cytokine receptor, Chemokine signaling pathway, interleukin-17 signaling pathway, and Toll-like receptor (TLR) signaling pathway. JUN, ALAS2, HBD, EPB42, TLR7, SLC4A1, and CXCR4 were identified as the hub genes nodes. The area under the ROC curve indicated that three hub genes have high diagnostic value in IPAH with AUC of 0.934 [95% confidence interval (CI): 0.849-0.979] in TLR7, 0.910 (95% CI: 0.818-0.965) in JUN, and 0.895 (95% CI: 0.800-0.955) in CXCR4. The identified candidate key genes and pathways help us understand the molecular mechanisms underlying the pathogenesis of IPAH. TLR7, JUN, and CXCR4 may be novel biomarkers in IPAH diagnosis.

Long-term treatment of pulmonary arterial hypertension with macitentan in Japanese patients

Objective: Macitentan, a novel dual endothelin receptor antagonist, was approved for the treatment of pulmonary arterial hypertension (PAH) in Japan. However, long-term effects in Japanese patients of macitentan are currently unavailable. This study sought to assess the long-term efficacy and safety of macitentan in Japanese patients with PAH.Methods: In this multicenter, open-label, clinical extension study (JapicCTI-121986), efficacy was evaluated based on the change from baseline at 24, 48, 72, 96 and 120-week in the 6-minute walk distance (6MWD), World Health Organization (WHO) functional class, and serum N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels. In addition, the time to a hospitalization related to PAH and a morbidity/mortality event was determined. As for safety, the incidence of adverse events and changes in laboratory data and vital signs were assessed.Results: Macitentan was administered at a once-daily dose of 10 mg in 30 PAH patients with a median treatment period of 2.4 years (range, 229-1037 days). The improvements in 6MWD, WHO functional class and NT-pro-BNP at week 24 were maintained throughout the long-term follow-up. Hospitalization related to PAH occurred in 2 patients. Levels of liver enzyme and hemoglobin remained unchanged throughout the study period.Conclusions: This study suggests that the long-term use of macitentan is well tolerated and effective in Japanese patients with PAH. We concluded that macitentan can be a possible approach to reduce morbidity/mortality in Japanese PAH patients.

Novel Molecular Mechanisms of Pulmonary Hypertension: A Search for Biomarkers and Novel Drug Targets-From Bench to Bed Site

Pulmonary hypertension (PH) is defined as increased mean pulmonary artery pressure (mPAP) above 25 mmHg, measured at rest by right heart catheterization. The exact global prevalence of PH is difficult to estimate, mainly due to the complex aetiology, and its spread may be underestimated. To date, numerous studies on the aetiology and pathophysiology of PH at molecular level were conducted. Simultaneously, some clinical studies have shown potential usefulness of well-known and widely recognized cardiovascular biomarkers, but their potential clinical usefulness in diagnosis and management of PH is poor due to their low specificity accompanied with numerous other cardiovascular comorbidities of PH subjects. On the other hand, a large body of basic research-based studies provides us with novel molecular pathomechanisms, biomarkers, and drug targets, according to the evidence-based medicine principles. Unfortunately, the simple implementation of these results to clinical practice is impossible due to a large heterogeneity of the PH pathophysiology, where the clinical symptoms constitute only a common denominator and a final result of numerous crosstalking metabolic pathways. Therefore, future studies, based mostly on translational medicine, are needed in order to both organize better the pathophysiological classification of various forms of PH and define precisely the optimal diagnostic markers and therapeutic targets in particular forms of PH. This review paper summarizes the current state of the art regarding the molecular background of PH with respect to its current classification. Novel therapeutic strategies and potential biomarkers are discussed with respect to their limitations in use in common clinical practice.

Overexpression of MicroRNA-340-5p Inhibits Pulmonary Arterial Hypertension Induced by APE by Downregulating IL-1β and IL-6

Pulmonary arterial hypertension (PAH) is a fatal cardiovascular disease that could eventually result in right ventricular failure. Recently, the roles of microRNAs (miRNAs) in PAH have been highlighted. The present study aims to investigate the effects of miRNA (miR)-340-5p on PAH induced by acute pulmonary embolism (APE) and the underlying mechanisms. miR-340-5p was lowly expressed, whereas interleukin 1β (IL-1β) and IL-6 were highly expressed in plasma of APE-PAH patients as compared to normal human plasma. Subsequently, IL-1β and IL-6 were confirmed to be two target genes of miR-340-5p using a dual-luciferase reporter gene assay. By conducting overexpression and rescue experiments, overexpression of miR-340-5p was evidenced to inhibit proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) and inflammation via reducing IL-1β and IL-6 levels. Meanwhile, miR-340-5p led to the blocked nuclear factor κB (NF-κB) pathway with reduced NF-κB p65, matrix metalloproteinase 2 (MMP2), and MMP9 expression in PASMCs. Finally, the ameliorative effect of miR-340-5p on pathological lesions was further verified in rat models of APE-PAH. Altogether, overexpressed miR-340-5p inhibited the inflammatory response, proliferation, and migration of PASMCs by downregulating IL-1β and IL-6, thereby suppressing the progression of APE-PAH. miR-340-5p therefore holds promise as an anti-inflammatory therapeutic target.

3D in vitro Model of Vascular Medial Thickening in Pulmonary Arterial Hypertension

In pulmonary arterial hypertension (PAH), excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) causes vascular medial thickening. Medial thickening is a histopathological hallmark of pulmonary vascular remodeling, the central disease process driving PAH progression. Pulmonary vascular remodeling causes stenosis and/or obstruction of small pulmonary arteries. This leads to increased pulmonary vascular resistance, elevated pulmonary arterial pressure, and ultimately right heart failure. To improve the survival of PAH patients, which remains at approximately 60% at 3 years after diagnosis, the development of novel PAH-targeted drugs is desired. To this end, a detailed understanding of the mechanisms underlying excessive PASMC proliferation and the medial thickening that ensues is necessary. However, a lack of in vitro models that recapitulate medial thickening impedes our deeper understanding of the pathogenetic mechanisms involved. In the present study, we applied 3-dimensional (3D) cell culture technology to develop a novel in vitro model of the pulmonary artery medial layer using human PAH patient-derived PASMCs. The addition of platelet-derived growth factor (PDGF)-BB, a mitogen known to promote excessive PASMC proliferation in PAH, resulted in increased thickness of the 3D-PAH media tissues. Conversely, administration of the PDGF receptor inhibitor imatinib or other clinical PAH drugs inhibited this medial thickening-inducing effect of PDGF-BB. Altogether, by using 3D cell culture technology, we report the generation of an in vitro model of medial thickening in PAH, which had hitherto not been successfully modeled in vitro. This model is potentially useful for assessing the ability of candidate PAH drugs to suppress medial thickening.

Age-related differences in hemodynamics and functional status in pulmonary arterial hypertension: Baseline results from the Pulmonary Hypertension Association Registry

BACKGROUND

The age of patients with pulmonary arterial hypertension (PAH) has increased, with registries now reporting mean ages of 50 to 65 years old. Limited data exist on age-related differences in hemodynamic and functional assessments in PAH.

METHODS

Adults with PAH in the Pulmonary Hypertension Association Registry were divided into 3 groups (18-50, 51-65, and >65 years old). Analysis of variance and chi-square testing were used to assess for baseline differences. Linear regression was used to examine the association of age with continuous hemodynamic and functional variables.

RESULTS

A total of 769 patients with mean age of 56 ± 16 years were included. Older patients had more connective tissue disease-associated PAH and less drug-associated PAH. In linear regression models, each year of increased age was associated with shorter 6-minute walk distance (-3.37 meters; 95% CI, -3.97 to -2.76), lower mean pulmonary arterial pressure (-0.21 mm Hg; 95% CI, -0.27 to -0.15), and lower pulmonary vascular resistance (-0.06 Wood units; 95% CI, -0.09 to -0.04). Pulmonary arterial compliance, cardiac index, right ventricular stroke work index, and percent predicted 6-minute walk distance were unrelated to age; resistance-compliance time was negatively related to age (-3 milliseconds per year; 95% CI, -4 to -2).

CONCLUSIONS

Relative to their pulmonary vascular resistance, older patients have lower pulmonary artery compliance and worse right ventricular performance. Based on these findings, we suspect that age influences right ventricular loading conditions and the response of the right ventricle to increased afterload.

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.

A non-selective endothelin receptor antagonist bosentan modulates kinetics of bone marrow-derived cells in ameliorating pulmonary hypertension in mice

The aim of this study was to investigate whether a dual endothelin receptor antagonist bosentan modulates the kinetics of bone marrow-derived stem cells in inhibiting the development of pulmonary hypertension. Bone marrow chimeric mice, transplanted with enhanced green fluorescent protein (eGFP)-positive bone marrow mononuclear cells, were exposed to hypobaric hypoxia or kept in the ambient air, and were daily treated with bosentan sodium salt or saline for 21 days. After the treatment period, right ventricular pressure was measured and pulmonary vascular morphometry was conducted. Incorporation of bone marrow-derived cells was analyzed by immunohistochemistry. Gene expression and protein level in the lung tissue were evaluated by quantitative real-time PCR and western blotting, respectively. The results showed that, in hypoxic mice, right ventricular pressure and the percentage of muscularized vessel were increased and pulmonary vascular density was decreased, each of which was reversed by bosentan. Bone marrow-derived endothelial cells and macrophages in lungs were increased by hypoxia. Bosentan promoted bone marrow-derived endothelial cell incorporation but inhibited macrophage infiltration into lungs. Quantitative real-time PCR analysis revealed that interleukin 6, stromal cell-derived factor-1, and monocyte chemoattractant protein-1 were upregulated by hypoxia, in which interleukin 6 and monocyte chemoattractant protein-1 were downregulated and stromal cell-derived factor-1 was upregulated by bosentan. Protein level of endothelial nitric oxide synthase (eNOS) in the whole lung was significantly upregulated by hypoxia, which was further upregulated by bosentan. Bosentan modulated kinetics of bone marrow-derived ECs and macrophages and related gene expression in lungs in ameliorating pulmonary hypertension in mice. Altered kinetics of bone marrow-derived stem cells may be a novel mechanism of the endothelin receptor blockade in vivo and confer a new understanding of the therapeutic basis for pulmonary hypertension.