Pulmonary arterial hypertension: from the kingdom of the near-dead to multiple clinical trial meta-analyses

1,8-Cineole reduces pulmonary vascular remodelling in pulmonary arterial hypertension by restoring intercellular communication and inhibiting angiogenesis

BACKGROUND

Pulmonary Arterial Hypertension (PAH) is characterized by pulmonary vascular remodelling, often associated with disruption of BMPR2/Smad1/5 and BMPR2/PPAR-γ signalling pathways that ultimately lead to right ventricle failure. Disruption of intercellular junctions and communication and a pro-angiogenic environment are also characteristic features of PAH. Although, current therapies improve pulmonary vascular tone, they fail to tackle other key pathological features that could prevent disease progression. In this scenario, aromatic plants emerge as promising sources of bioactive compounds, with 1,8-cineole standing out due to its hypotensive properties and cardioprotective effect in PAH.

PURPOSE

The present study aims to explore for the first time the effect of 1,8-cineole in pulmonary vascular remodelling associated with PAH.

METHODS

Resorting to the monocrotaline (MCT)-induced PAH animal model, the effect of 1,8-cineole on vascular remodelling including interstitial collagen accumulation, smooth muscle cell proliferation and protein levels of BMPR2 pathway-related proteins, was assessed by microscopy and western blot (WB) analysis. The integrity of gap junctions, pulmonary surfactant, mitochondrial structure and endothelial cell barrier were evaluated by transmission electron microscopy, confocal microscopy and WB analysis. Furthermore, the effect of 1,8-cineole on angiogenesis was determined on pulmonary artery endothelial cells (PAEC) submitted to hypoxia using the scratch wound and Matrigel angiogenesis assays, and the number of sprouts on isolated healthy and diseased pulmonary artery rings, treated with the compound, enabled the validation of these effects.

RESULTS

1,8-Cineole mitigated PAH-associated derailment of both BMPR2/Smad1/5 and BMPR2/PPAR-γ pathways and concomitantly reduced interstitial fibrosis and the arterial medial layer thickness in pulmonary arteries. The compound restored gap junction, lung surfactant and mitochondrial integrity and preserved endothelial barrier integrity. Furthermore, 1,8-cineole exerted an anti-angiogenic effect, by impairing the formation of vessel-like structures in PAEC and sprouting formation in isolated pulmonary arteries.

CONCLUSION

The present study brings new insights about the mechanisms whereby 1,8-cineole impacts pulmonary vascular remodelling and demonstrates the potential of 1,8-cineole as a therapeutic strategy to hamper PAH progression.

Pulmonary arterial hypertension: Navigating the pathways of progress in diagnosis, treatment, and patient care

Pulmonary arterial hypertension (PAH) is a form of precapillary pulmonary hypertension caused by a complex process of endothelial dysfunction and vascular remodeling. If left untreated, this progressive disease presents with symptoms of incapacitating fatigue causing marked loss of quality of life, eventually culminating in right ventricular failure and death. Patient management is complex and based on accurate diagnosis, risk stratification, and treatment initiation, with close monitoring of response and disease progression. Understanding the underlying pathophysiology has enabled the development of multiple drugs directed at different targets in the pathological chain. Vasodilator therapy has been the mainstay approach for the last few years, significantly improving quality of life, functional status, and survival. Recent advances in therapies targeting dysfunctional pathways beyond endothelial dysfunction may address the fundamental processes underlying the disease, raising the prospect of increasingly effective options for this high-risk group of patients with a historically poor prognosis.

Unraveling the role of HIF and epigenetic regulation in pulmonary arterial hypertension: implications for clinical research and its therapeutic approach

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling with high pulmonary pressure, which ultimately leads to right heart failure and premature death. Emerging evidence suggests that both hypoxia and epigenetics play a pivotal role in the pathogenesis of PAH development. In this review article, we summarize the current developments in regulation of hypoxia inducible factor (HIF) isoforms in PAH vascular remodeling and the development of suitable animal models for discovery and testing of HIF pathway-targeting PAH therapeutics. In addition, we also discuss the epigenetic regulation of HIF-dependent isoforms in PAH and its therapeutic potential from a new perspective which highlights the importance of HIF isoform-specific targeting as a novel salutary strategy for PAH treatment.

Prognostic role of haemodynamics at follow-up in patients with pulmonary arterial hypertension: a challenge to current European Society of Cardiology/European Respiratory Society risk tools

Background

Haemodynamic variables like right atrial pressure (RAP), cardiac index (CI), stroke volume index (SVI) and mixed venous oxygen saturation (S vO2 ) predict survival in patients with pulmonary arterial hypertension (PAH). However, there is the need to identify further prognostic haemodynamic parameters as well as to redefine their role in PAH risk stratification compared to current risk tools and non-invasive parameters.

Methods

This cohort study includes treatment-naïve patients assessed at baseline and after first-line PAH therapy with clinical, functional, exercise, laboratory and haemodynamic evaluations. Using a stepwise multivariate Cox regression analysis, independent prognostic haemodynamic parameters were identified and stratified according to cut-offs already defined in the European Society of Cardiology (ESC)/European Respiratory Society (ERS) risk table or defined based on the highest Chi-squared of the log-rank test. Their discriminatory power was tested for all-cause death and a combined end-point of death, hospitalisation and need of treatment escalation.

Results

794 patients with PAH were enrolled. At first follow-up, RAP and pulmonary artery elastance were independently associated with death. Because of high correlations between haemodynamic parameters, different multivariable analyses were done identifying six other variables (pulmonary arterial compliance, cardiac efficiency, pulmonary vascular resistance, S vO2 , CI and SVI). Haemodynamic parameters were of no added prognostic value compared to ESC/ERS risk tools for the all-cause death end-point but they showed additional value to non-invasive parameters for the combined end-point and, when taken alone, had a discriminatory capacity comparable to ESC/ERS risk tools.

Conclusion

Haemodynamics' discriminative ability for clinical worsening is comparable to current ESC/ERS risk tools and is of added value to non-invasive parameters.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

Angiotensin-Converting Enzyme 2 (ACE2) Signaling in Pulmonary Arterial Hypertension: Underpinning Mechanisms and Potential Targeting Strategies

Pulmonary arterial hypertension (PAH) is a debilitating progressive disease characterized by excessive pulmonary vasoconstriction and abnormal vascular remodeling processes that lead to right-ventricular heart failure and, ultimately, death. Although our understanding of its pathophysiology has advanced and several treatment modalities are currently available for the management of PAH patients, none are curative and the prognosis remains poor. Therefore, further research is required to decipher the molecular mechanisms associated with PAH. Angiotensin-converting enzyme 2 (ACE2) plays an important role through its vasoprotective functions in cardiopulmonary homeostasis, and accumulating preclinical and clinical evidence shows that the upregulation of the ACE2/Angiotensin-(1-7)/MAS1 proto-oncogene, G protein-coupled receptor (Mas 1 receptor) signaling axis is implicated in the pathophysiology of PAH. Herein, we highlight the molecular mechanisms of ACE2 signaling in PAH and discuss its potential as a therapeutic target.

Lung Transplantation for Pulmonary Artery Hypertension

This manuscript discusses the role of lung transplantation in patients with pulmonary hypertension. The indications and timing for referral to a transplant unit and timing for wait-listing for lung transplantation are discussed. The type of transplantation—isolated (single or double) lung transplantation and situations when combined heart and double lung transplantation is indicated—will be elaborated. Escalation of medical therapy with the need and timing for bridging therapies such as extracorporeal membrane oxygenation until an appropriate organ becomes available will be discussed. Challenges in the postoperative period, specific to lung transplantation for pulmonary artery hypertension, will be reviewed. The outcomes following lung transplantation will also be considered in greater detail.

The evolving landscape of pulmonary arterial hypertension clinical trials

Although it is a rare disease, the number of available therapeutic options for treating pulmonary arterial hypertension has increased since the late 1990s, with multiple drugs developed that are shown to be effective in phase 3 randomised controlled trials. Despite considerable advancements in pulmonary arterial hypertension treatment, prognosis remains poor. Existing therapies target pulmonary endothelial dysfunction with vasodilation and anti-proliferative effects. Novel therapies that target proliferative vascular remodelling and affect important outcomes are urgently needed. There is need for additional innovations in clinical trial design so that all emerging candidate therapies can be rigorously studied. Pulmonary arterial hypertension trial design has shifted from short-term submaximal exercise capacity as a primary endpoint, to larger clinical event-driven trial outcomes. Event-driven pulmonary arterial hypertension trials could face feasibility and efficiency issues in the future because increasing sample sizes and longer follow-up durations are needed, which would be problematic in such a rare disease. Enrichment strategies, innovative and alternative trial designs, and novel trial endpoints are potential solutions that could improve the efficiency of future pulmonary arterial hypertension trials while maintaining robustness and clinically meaningful evidence.

Sox17 Deficiency Promotes Pulmonary Arterial Hypertension via HGF/c-Met Signaling

BACKGROUND

In large-scale genomic studies, Sox17, an endothelial-specific transcription factor, has been suggested as a putative causal gene of pulmonary arterial hypertension (PAH); however, its role and molecular mechanisms remain to be elucidated. We investigated the functional impacts and acting mechanisms of impaired Sox17 (SRY-related HMG-box17) pathway in PAH and explored its potential as a therapeutic target.

METHODS

In adult mice, Sox17 deletion in pulmonary endothelial cells (ECs) induced PAH under hypoxia with high penetrance and severity, but not under normoxia.

RESULTS

Key features of PAH, such as hypermuscularization, EC hyperplasia, and inflammation in lung arterioles, right ventricular hypertrophy, and elevated pulmonary arterial pressure, persisted even after long rest in normoxia. Mechanistically, transcriptomic profiling predicted that the combination of Sox17 deficiency and hypoxia activated c-Met signaling in lung ECs. HGF (hepatocyte grow factor), a ligand of c-Met, was upregulated in Sox17-deficient lung ECs. Pharmacologic inhibition of HGF/c-Met signaling attenuated and reversed the features of PAH in both preventive and therapeutic settings. Similar to findings in animal models, Sox17 levels in lung ECs were repressed in 26.7% of PAH patients (4 of 15), while those were robust in all 14 non-PAH controls. HGF levels in pulmonary arterioles were increased in 86.7% of patients with PAH (13 of 15), but none of the controls showed that pattern.

CONCLUSIONS

The downregulation of Sox17 levels in pulmonary arterioles increases the susceptibility to PAH, particularly when exposed to hypoxia. Our findings suggest the reactive upregulation of HGF/c-Met signaling as a novel druggable target for PAH treatment.

Skeletal muscle blood flow during exercise is reduced in a rat model of pulmonary hypertension

Pulmonary arterial hypertension (PAH) is characterized by exercise intolerance. Muscle blood flow may be reduced during exercise in PAH; however, this has not been directly measured. Therefore, we investigated blood flow during exercise in a rat model of monocrotaline (MCT)-induced pulmonary hypertension (PH). Male Sprague-Dawley rats (∼200 g) were injected with 60 mg/kg MCT (MCT, n = 23) and vehicle control (saline; CON, n = 16). Maximal rate of oxygen consumption (V̇o2max) and voluntary running were measured before PH induction. Right ventricle (RV) morphology and function were assessed via echocardiography and invasive hemodynamic measures. Treadmill running at 50% V̇o2max was performed by a subgroup of rats (MCT, n = 8; CON, n = 7). Injection of fluorescent microspheres determined muscle blood flow via photo spectroscopy. MCT demonstrated a severe phenotype via RV hypertrophy (Fulton index, 0.61 vs. 0.31; P < 0.001), high RV systolic pressure (51.5 vs. 22.4 mmHg; P < 0.001), and lower V̇o2max (53.2 vs. 71.8 mL·min-1·kg-1; P < 0.0001) compared with CON. Two-way ANOVA revealed exercising skeletal muscle blood flow relative to power output was reduced in MCT compared with CON (P < 0.001), and plasma lactate was increased in MCT (10.8 vs. 4.5 mmol/L; P = 0.002). Significant relationships between skeletal blood flow and blood lactate during exercise were observed for individual muscles (r = -0.58 to -0.74; P < 0.05). No differences in capillarization were identified. Skeletal muscle blood flow is significantly reduced in experimental PH. Reduced blood flow during exercise may be, at least in part, consequent to reduced exercise intensity in PH. This adds further evidence of peripheral muscle dysfunction and exercise intolerance in PAH.

The evolution of survival of pulmonary arterial hypertension over 15 years

The prognosis of pulmonary arterial hypertension (PAH) remains dismal. Over the years, multiple therapeutic advances have been introduced. This study evaluates the evolution of PAH survival over the past 15 years. We included 293 consecutive adult patients diagnosed with PAH between 2005 and 2019 (median age: 61.8 years, 70.3% female). Patients were divided into three cohorts based on the time of diagnosis: 2005-2009, 2010-2014, and 2015-2019 (2005-2009: n = 56; 2010-2014: n = 111; 2015-2019: n = 126). Transplant-free survival was measured from the date of right heart catheterization until patients reached the composite endpoint of lung transplant or death. Multivariable cox-pulmonary hypertension regression was used to study the effect of the time of diagnosis. The final cox model was fitted in both younger and older patients to evaluate the difference between these groups. During a median follow-up time of 4.1 (interquartile range: 2.2-7.3) years, 9 patients underwent lung transplantation and 151 patients died. The median overall transplant-free survival was 6.2 (5.5-8.0) years. Patients older than 56 years at baseline who were diagnosed in 2005-2009 showed better survival compared to patients diagnosed in 2010-2014 and 2015-2019 with an adjusted hazard ratio of, respectively, 2.12 (1.11-4.03) and 2.83 (1.41-5.69). Patients younger than 56 years showed neither an improved nor deteriorated survival over time. In conclusion, survival in patients with PAH did not improve over time, despite more available therapeutic options. This might be partly due to the changed demographic characteristics of the PAH patients and a still important diagnostic delay.

Selexipag-based triple combination therapy improves prognosis in Chinese pulmonary arterial hypertension patients

Aim

Selexipag is an oral selective prostacyclin receptor agonist approved for treatment of patients with pulmonary arterial hypertension (PAH). In the present study, we aim to assess the safety and efficacy of selexipag in triple combination therapy with endothelial receptor antagonists (ERAs) and PDE5is for Chinese PAH patients.

Methods and results

A single center retrospective study was performed on group 1 PAH patients (n = 68) initiating triple combination therapy with selexipag from 1 February 2020 to 31 August 2021 in Qilu Hospital of Shandong University (Shandong, China). Adolescents, children, and PAH patients with unrepaired congenital heart disease were excluded. The French pulmonary hypertension network (FPHN) non-invasive risk assessment, echocardiogram parameters, and clinical data, including tolerability, safety, and death/hospitalization events associated with PAH, were collected. Of the 68 patients, 31 (45.6%) patients had tolerable side effects while only a single patient discontinued selexipag due to severe diarrhea. In the analysis of the efficacy set of 62 patients, the median selexipag treatment time from selexipag initiation to last risk assessment was 27 (21, 33) weeks. Compared to baseline parameters, the percentage of WHO FC III/IV decreased from 77.4% (48) to 24.2% (15) (p = 0.000), median 6-min walk distance (6MWD) increased 82 m [from 398 (318, 450) to 480 (420, 506) m; p = 0.000], and NT-proBNP levels decreased from 1,216 (329, 2,159) to 455 (134, 1,678) pg/mL (p = 0.007). Patients who improved to three low-risk criteria increased from 9.7 to 38.7%. Right ventricular diameter (RV) diameter also decreased and was accompanied by an improved tricuspid annular plane systolic excursion (TAPSE). Patients transitioning from subcutaneous treprostinil to selexipag continued to show improvements in WHO FC, 6MWD (404 ± 94 vs. 383 ± 127 m) and NT-proBNP levels (2,319 ± 2,448 vs. 2,987 ± 3,770 pg/mL). Finally, the 1-year event free survival rate was 96.7% for patients initiating the triple combination therapy within 3 years of PAH diagnosis.

Conclusion

Triple combination therapy with selexipag was safe and effective in Chinese PAH patients, which was confirmed by acceptable tolerability, and improved exercise capacity, right heart function, risk assessment, and prognosis.

Efficacy and safety of sequential combination therapy for pulmonary arterial hypertension: A meta-analysis of Randomized-Controlled Trials

BACKGROUND

Previous meta-analyses of pulmonary arterial hypertension (PAH) combination therapy pooled sequential and initial combination together, which might threaten their authenticity and clinical significance for the difference between two strategies.

METHODS

PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials (RCTs) that compared sequential combination therapy (SCT) with background therapy (BT) in PAH patients. Raw data were extracted to calculate risk ratio (RR) or weighted mean difference (WMD) for predefined efficacy and safety outcomes. Mantel-Haenszel fixed or random effects model was used based on heterogeneity.

RESULTS

17 RCTs involving 4343 patients (97.2% of patients with WHO-FC II-III) were included. SCT decreased clinical worsening (RR 0.66, 95% CI 0.58 to 0.76), nonfatal clinical worsening (RR 0.61, 95% CI 0.52 to 0.71), functional class (decrease of 28% in the portion of patients with WHO-FC worsening and increase of 33% in the portion of patients with WHO-FC improvement), and increased 6-min walk distance (WMD 17.68 m, 95% CI 10.16 to 25.20), but didn't reduce mortality, lung transplantation, admission to hospital, and treatment escalation compared with BT. Although any adverse event and serious adverse event were similar between SCT and BT, SCT increased all-cause treatment discontinuation (RR 1.49, 95% CI 1.30 to 1.71) and drug-related treatment discontinuation (RR 2.30, 95% CI 1.86 to 2.84) with higher incidence of headache, flushing, nausea, diarrhoea and jaw pain.

CONCLUSIONS

For WHO-FC II-III PAH patients who have established BT, our study reinforced the recommendation of SCT to improve clinical worsening, functional status, and exercise capacity, although with higher incidence of side-effects and withdrawal.

Real-world treatment patterns, healthcare resource utilization, and cost among adults with pulmonary arterial hypertension in the United States

Treatment for pulmonary arterial hypertension (PAH) has evolved over the past decade, including approval of new medications and growing evidence to support earlier use of combination therapy. Despite these changes, few studies have assessed real-world treatment patterns, healthcare resource utilization (HCRU), and costs among people with PAH using recent data. We conducted a retrospective cohort study using administrative claims from the HealthCore Integrated Research Database®. Adult members with claims for a PAH diagnosis, right heart catheterization, and who initiated PAH treatment (index date) between October 1, 2015 and November 30, 2020 were identified. Members had to be continuously enrolled in the health plan for 6 months before the index date (baseline) and ≥30 days after. Treatment patterns, HCRU, and costs were described. A total of 843 members with PAH (mean age 62.3 years, 64.2% female) were included. Only 21.0% of members received combination therapy as their first-line treatment, while most members (54.6%) received combination therapy as second-line treatment. All-cause HCRU remained high after treatment initiation with 58.0% of members having ≥1 hospitalization and 41.3% with ≥1 emergency room visit. Total all-cause costs declined from $15,117 per patient per month at baseline to $14,201 after treatment initiation, with decreased medical costs ($14,208 vs. $6,349) more than offsetting increased pharmacy costs ($909 vs. $7,852). In summary, despite growing evidence supporting combination therapy, most members with PAH initiated treatment with monotherapy. Total costs decreased following treatment, driven by a reduction in medical costs even with increases in pharmacy costs.

Pulmonary Hypertension in Adult Congenital Heart Disease in Asia: A Distinctive Feature of Complex Congenital Heart Disease

Background

The epidemiology of pulmonary hypertension (PH) in patients with adult congenital heart disease in Western countries is already known. We investigate clinical characteristics of PH in adult congenital heart disease with emphasis on complex congenital heart disease (CHD) from an Asian cohort in Taiwan.

Methods and Results

All adult patients (aged >18 years) diagnosed with CHD between January 2007 and July 2018 qualified for the study. PH was determined by cardiac catheterization data or echocardiography reports. In accord with the World Symposia on Pulmonary Hypertension, CHD was further categorized as simple, severe, or complex CHD (including pulmonary atresia‐ventricular septal defect and single‐ventricle anomalies).

There were 4301 patients (55.6% women), 15.7% with severe and 3.9% with complex CHD. The cumulative incidence of PH was 4.4% (95% CI, 3.8–5.0). Our multivariable regression model indicated 4.2‐fold mortality increase (95% CI, 3.0–5.9) in the presence of PH, with age, female sex, and severe or complex CHD linked to higher incidence of PH. Only 49% of patients received PH‐specific therapy. Five‐ and 10‐year survival rates of patients with PH (n=190) were 72.3% (95% CI, 65.1%–78.4%) and 58.8% (95% CI, 50.1%–66.5%), respectively. Survival rates in those with Eisenmenger syndrome, PH after defect correction, and complex CHD were similar. Low oxygen saturation and high uric acid levels were associated with increased mortality.

Conclusions

In this sizable Asian adult CHD cohort, the cumulative incidence of PH was aligned with that of Western countries. Mortality proved higher in patients with PH versus without PH. Although complex CHD carried greater risk of PH compared with other adult CHD subsets, survival rate was similar.

Validity of the ESC Risk Assessment in Idiopathic Pulmonary Arterial Hypertension in China

Background: The 2015 European pulmonary hypertension (PH) guidelines recommend a risk stratification strategy for pulmonary arterial hypertension (PAH). We aimed to investigate the validation and potential prognostic information in Chinese patients. Methods: The risk assessment variables proposed by the PH guidelines were performed by using the WHO function class, 6-min walking distance, brain natriuretic peptide or its N-terminal fragment, right arterial pressure, cardiac index, mixed venous saturation, right atrium area, pericardial effusion, peak oxygen consumption, and ventilatory equivalents for carbon dioxide. An abbreviated version also was applied. Results: A total of 392 patients with idiopathic PAH (IPAH) were enrolled between 2009 and 2018. After a median interval of 13 months, re-evaluation assessments were available for 386 subjects. The PAH guidelines risk tool may effectively discriminate three risk groups and mortality (p < 0.001) both at the baseline and re-evaluation. Meanwhile, its simplified risk version was valid for baseline and accurately predicted the risk of death in all the risk groups (p < 0.001). At the time of re-evaluation, the percentage of low-risk group has an increase, but a greater proportion achieved the high-risk group and a lesser proportion maintained in the intermediate-risk group. Conclusion: The 2015 European PH guidelines and its simplified version risk stratification assessment present an effective discrimination of different risk groups and accurate mortality estimates in Chinese patients with IPAH. Changes of risk proportion at re-evaluation implicated that natural treatment decisions may not be consistently with goal-oriented treatment strategy.

Non-Invasive Risk Prediction Based on Right Ventricular Function in Patients with Pulmonary Arterial Hypertension

BACKGROUND

Right ventricular dysfunction is a major determinant of outcome in pulmonary arterial hypertension (PAH). We aimed to identify echocardiographic right heart parameters associated with adverse outcome and to develop a non-invasive, echocardiography-based risk score for PAH patients.

METHODS AND RESULTS

In 254 PAH patients we analyzed functional status, laboratory results, and echocardiographic parameters. We included these parameters to estimate all-cause death or lung transplantation using Cox regression models. The analyses included a conventional model using guideline-recommended variables and an extended echocardiographic model. Based on the final model a 12-point risk score was derived, indicating the association with the primary outcome within five years. During a median follow-up time of 4.2 years 74 patients died or underwent lung transplantation. The conventional model resulted in a C-Index of 0.539, whereas the extended echocardiographic model improved the discrimination (C-index 0.639, p-value 0.017). Ultimately, the newly developed risk score included WHO functional class, 6-min walking distance, N-terminal brain natriuretic peptide concentrations, pericardial effusion, right atrial area, tricuspid annular plane systolic excursion, and fractional area change.

CONCLUSION

Integrating right heart function assessed by echocardiography improves prediction of death or lung transplantation in PAH patients. Independent validation of this finding is warranted.

Cardiovascular Diseases That Have Emerged From the Darkness

It is important for both the patient and physician communities to have timely access to information recognizing rapid progress in the diagnosis and treatment of familiar but relatively uncommon cardiovascular diseases. Patients with 3 cardiovascular diseases (ie, hypertrophic cardiomyopathy, pulmonary arterial hypertension, and transthyretin (TTR) cardiac amyloidosis (ATTR)]), once considered rare without effective management options and associated with malignant prognosis, have now benefited substantially from the development of a variety of innovative therapeutic strategies. In addition, in each case, enhanced diagnostic testing has expanded the patient population and allowed for more widespread administration of contemporary treatments. In hypertrophic cardiomyopathy, introduction of implantable defibrillators to prevent sudden death as well as high-benefit:low-risk septal reduction therapies to reverse heart failure have substantially reduced morbidity and disease-related mortality (to 0.5% per year). For pulmonary arterial hypertension, a disease once characterized by a particularly grim prognosis, prospective randomized drug trials with aggressive single (or combined) pharmacotherapy have measurably improved survival and quality of life for many patients. In cardiac amyloidosis, development of disease-specific drugs can for the first time reduce morbidity and mortality, prominently with breakthrough ATTR-protein-stabilizing tafamidis. In conclusion, in less common and visible cardiovascular diseases, it is crucial to recognize substantial progress and achievement, given that penetration of such information into clinical practice and the patient community can be inconsistent. Diseases such as hypertrophic cardiomyopathy, pulmonary arterial hypertension, and ATTR cardiac amyloidosis, once linked to a uniformly adverse prognosis, are now associated with the opportunity for patients to experience satisfactory quality of life and extended longevity.

A pragmatic approach to risk assessment in pulmonary arterial hypertension using the 2015 European Society of Cardiology/European Respiratory Society guidelines

OBJECTIVE

To optimise treatment of patients with pulmonary arterial hypertension (PAH), the 2015 European Society of Cardiology/European Respiratory Society guidelines recommend using risk stratification, with the aim of patients achieving low-risk status. Previous analyses of registries made progress in using risk stratification approaches, however, the focus is often on patients with a low-risk prognosis, whereas most PAH patients are in intermediate-risk or high-risk categories. Using only six parameters with high prognostic relevance, we aimed to demonstrate a pragmatic approach to individual patient risk assessment to discriminate between patients at low risk, intermediate risk and high risk of death.

METHODS

Risk assessment was performed combining six parameters in four criteria: (1) WHO functional class, (2) 6 min walk distance, (3) N-terminal pro-brain natriuretic peptide (BNP)/BNP plasma levels or right atrial pressure and (4) cardiac index or mixed venous oxygen saturation. Assessments were made at baseline and at first follow-up after 3-4 months.

RESULTS

725 PAH treatment-naive patients were analysed. Survival estimates between risk groups were statistically significant at baseline and first follow-up (p<0.001), even when the analysis was performed within PAH etiological subgroups. Similar results were observed in 208 previously treated PAH patients. Furthermore, patients who remained at or improved to low risk had a significantly better estimated survival compared with patients who remained at or worsened to intermediate risk or high risk (p≤0.005).

CONCLUSION

The simplified risk-assessment method can discriminate idiopathic, connective-tissue-disease-associated and congenital-heart-disease-associated PAH patients into meaningful high-risk, intermediate-risk and low-risk groups at baseline and first follow-up. This pragmatic approach reinforces targeting a low-risk profile for PAH patients.

Novel Treatment Pathways in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe and progressive vascular disease characterized by pulmonary vascular remodeling, proliferation, and inflammation. Despite the availability of effective treatments, PAH may culminate in right ventricular failure and death. Currently approved medications act through three well-characterized pathways: the nitric oxide, endothelin, and prostacyclin pathways. Ongoing research efforts continue to expand our understanding of the molecular pathogenesis of this complex and multifactorial disease. Based on recent discoveries in the pathobiology of PAH, several new treatments are being developed and tested with the goal of modifying the disease process and ultimately improving the long-term prognosis.

Epoprostenol for the treatment of pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a rare, progressive, and severe disease. Since the first demonstration of survival benefit of intravenous epoprostenol in monotherapy in 1996, prostanoids remain the cornerstone for PAH patients at high risk. This review is essential to understand the current situation of this drug among all the therapeutic possibilities concerning this entity.Areas covered: The aim of this article is to review the pharmacological properties of epoprostenol and to update its clinical evidence in different specific clinical scenarios. A deep literature search was carried out on the MEDLINE database for published literature before March 2021.Expert opinion: Epoprostenol is still the best treatment option for high-risk PAH patients. Nevertheless, there are many unsolved questions: drug dosing, its use in combination therapy with other pulmonary vasodilators, and the utility in PAH associated with connective tissue disease, congenital heart disease, or pulmonary veno-occlusive disease are only a few examples. Its safety and efficacy are supported by clinical trials, observational work, and experience, both as monotherapy and in combination therapy. Epoprostenol should be considered a destination treatment in high-risk patients and not only as a bridge to pulmonary transplantation. However, it remains underused in clinical practice.

High Right Ventricular Afterload during Exercise in Patients with Pulmonary Arterial Hypertension

The right ventricle (RV) is more sensitive to an increase in afterload than the left ventricle (LV), and RV afterload during exercise increases more easily than LV afterload. Pulmonary arterial hypertension (PAH)-specific therapy has improved pulmonary hemodynamics at rest; however, the pulmonary hemodynamic response to exercise is still abnormal in most patients with PAH. In these patients, RV afterload during exercise could be higher, resulting in a greater increase in RV wall stress. Recently, an increasing number of studies have indicated the short-term efficacy of exercise training. However, considering the potential risk of promoting myocardial maladaptive remodeling, even low-intensity repetitive exercise training could lead to long-term clinical deterioration. Further studies investigating the long-term effects on the RV and pulmonary vasculature are warranted. Although the indications for exercise training for patients with PAH have been expanding, exercise training may be associated with various risks. Training programs along with risk stratification based on the pulmonary hemodynamic response to exercise may enhance the safety of patients with PAH.

Monotherapy in patients with pulmonary arterial hypertension at four German PH centres

BACKGROUND

Although combination therapy is the gold standard for patients with pulmonary arterial hypertension (PAH), some of these patients are still being treated with monotherapy.

METHODS

We conducted a retrospective analysis at four German PH centres to describe the prevalence and characteristics of patients receiving monotherapy.

RESULTS

We identified 131 incident PAH patients, with a mean age of 64 ± 13.8 years and a varying prevalence of comorbidities, cardiovascular risk factors and targeted therapy. As in other studies, the extent of prescribed PAH therapy varied with age and coexisting diseases, and younger, so-called "typical" PAH patients were more commonly treated early with combination therapy (48% at 4-8 months). In contrast, patients with multiple comorbidities or cardiovascular risk factors were more often treated with monotherapy (69% at 4-8 months). Survival at 12 months was not significantly associated with the number of PAH drugs used (single, dual, triple therapy) and was not different between "atypical" and "typical" PAH patients (89% vs. 85%).

CONCLUSION

Although "atypical" PAH patients with comorbidities or a more advanced age are less aggressively treated with respect to combination therapy, the outcome of monotherapy in these patients appears to be comparable to that of dual or triple therapy in "typical" PAH patients.

Response to exercise in patients with pulmonary arterial hypertension treated with combination therapy

Pulmonary arterial hypertension (PAH)-specific combination therapy improves pulmonary haemodynamics at rest in patients with PAH; nevertheless, exertional dyspnoea remains. We investigated pulmonary haemodynamic response to exercise, and the relationship to ventilatory efficiency and hypoxaemia in patients with PAH treated with combination therapy. 32 clinically stable patients with PAH undergoing combination therapy underwent cardiopulmonary exercise testing with right heart catheterisation. Haemodynamic impairment was moderate to severe before treatment. However, after treatment it was significantly improved, and the mean pulmonary arterial pressure (mPAP) at rest was <25 mmHg in 13 patients. The mPAP increased significantly from 27.9±10.7 to 45.9±16.7 mmHg (p<0.01) during exercise. The cardiac index increased inadequately, and the total pulmonary resistance (TPR) increased significantly from 5.74±3.42 to 6.58±3.82 Wood units (p<0.01). The mPAP/cardiac output (CO) slope was steep (10.0±6.7 mmHg·min·L⁻¹). It significantly correlated with both the minute ventilation/carbon dioxide output slope (r=0.51, p<0.01) and peripheral arterial oxygen saturation/workload slope (r=−0.41, p=0.02). In addition, the mPAP/CO slope correlated significantly with mPAP at rest (r=0.73, p<0.01) and TPR at rest (r=0.64, p<0.01). Even after pulmonary haemodynamics at rest was significantly improved in PAH patients with PAH-specific combination therapy, the mPAP/CO slope was steep and the steep mPAP/CO slope related to decreased ventilatory efficiency and the severity of hypoxaemia. The mPAP/CO slope was steeper in patients with higher mPAP and TPR at rest.

Even after pulmonary haemodynamics at rest are improved in PAH patients with combination therapy, pulmonary haemodynamic response to exercise is abnormal, and related to abnormal respiratory response and the severity of hypoxaemiahttps://bit.ly/2HGS0TX

[Advantages and limitations of initial combination therapy in pulmonary arterial hypertension patients in Russia]

Pulmonary arterial hypertension (PAH) is severe and often times rapidly progressive disease with fatal outcome. The concept of initial combination of PAH-specific therapies in high risk patients at baseline was first described in the European guidelines on pulmonary hypertension (PH) in 2009, and in low or intermediate risk patients at baseline in 2015. Interestingly, that in Cologne Experts Consensus, and then in the 6th World Symposium on PH medical community started considering initial combination therapy as one of the most important pillars in PAH treatment algorithms in 2018. As of August 2020, as many as 8 formulations of 7 reference PAH-specific drugs are licensed for medical use in the Russian Federation. On top of that, 6 abbreviated drugs (generics) have also become available few years ago. Unfortunately, intravenous and subcutaneous prostacyclin analogs (PCA) and tadalafil are not approved for PH patients treatment in the Russian Federation. In this narrative review paper we attempted to describe studies on initial dual combination therapy with PAH-specific drugs registered in Russia, i.e. ambrisentan and riociguat, macitentan and riociguat, macitentan and sildenafil in low or intermediate risk patients at baseline, as well as iloprost inhaled and sildenafil, iloprost inhaled and bosentan in high risk patients. Some beneficial pharmacological effects due to the synergy between ambrisentan plus riociguat, and inhaled iloprost plus sildenafil appear to be interesting and require further clinical confirmation. Other initial combinations of PAH-specific agents require large-scale clinical trials as well.

Evaluation and management of pulmonary arterial hypertension

Pulmonary arterial hypertension is a devastating progressive disease mediated by different pathophysiologic pathways that result in progressive increase in pulmonary vascular resistance along with right ventricular failure and eventually premature death. Despite significant advances in the understanding of the underlying mechanisms and development of a number of targeted therapies, pulmonary arterial hypertension remains a challenging condition with high morbidity and mortality. New therapies are being actively sought, and early recognition remains of paramount importance. In an effort to improve the detection and management of pulmonary hypertension, the 6th World Symposium on Pulmonary Hypertension came up with most recent statements in 2018. The goal of this review is to summarize some key updates from the proceedings of the Symposium pertaining to different aspects of evaluation and management of patients with pulmonary arterial hypertension.

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.

Comparative tolerability of targeted therapies in pulmonary hypertension

Introduction

The objective of this study was to estimate the safety profile of pulmonary hypertension-specific therapies using placebo-controlled and active comparator trials.

Material and methods

The search corpus comprised Medline, Scopus, Embase and Clinical Trials databases. A systematic review and meta-analysis was performed to assess the relative risk of severe events and discontinuations as well as of adverse drug reactions (ADRs) classified into 26 categories and 21 subcategories defined by the Medical Dictionary for Regulatory Activities (MedRA).

Results

Pulmonary hypertension-specific therapies had the greatest effect on such events as flushing and headache as well as jaw pain, limb pain and myalgia or gastrointestinal disorders. The relative risk for ADRs in patients receiving monotherapy (vs. placebo/supportive therapies) and combined regimens (vs. monotherapy) was significantly increased. The risk of cessation for the combined regimen was slightly higher (Qinter-group, p = 0.0778). Such ADRs as blood and lymphatic system disorders with the anemia subgroup, gastrointestinal disorders with diarrhea and nausea subgroups, respiratory and thoracic diseases or nervous system disorders with headache tended to occur more often in combination regimens as compared to monotherapy.

Conclusions

About half of the main categories and subcategories of adverse reactions according to MedRA were associated with a relatively high frequency and hazard ratio. Their risk can be increased when combination regimens are used, especially.

Pulmonary arterial hypertension: Rationale for using multiple vs. single drug therapy

Pulmonary arterial hypertension (PAH) is defined by a heterogenous pathobiology that corresponds to variable clinical presentation, treatment response, and prognosis across affected patients. The approach to pharmacotherapeutics in PAH has evolved since the introduction of the first prostacyclin replacement drug, which was trialed in patients with end-stage disease as a strategy by which to delay or prevent mortality. Subsequently, the aim of care in PAH has shifted toward minimizing symptoms, improving functional capacity, delaying disease progression, and prolonging life. Thus, treatments are now implemented earlier and according to the evidence base, which spans more than twenty years and includes patients at various stages of disease. Overall, the evidence supports multidrug therapy rather than monotherapy in the majority of PAH patients. Among incident patients, up-front combination therapy with ambrisentan and tadalafil or other comparable agents within these drug classes is recommended based on strong clinical trial data. In the near future, up-front triple therapy may be emerge as bona fide treatment approach in selected patients. Future goals that are already under consideration in PAH include stronger integration of pathobiological characteristics when considering the use of specific drugs, or the development of novel therapies, toward precision medicine-based clinical pharmacology.

Immunotherapy of Endothelin-1 Receptor Type A for Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a chronic fatal disease. The treatment of PAH is less than ideal and the control is far from satisfactory worldwide. Vaccination provides a promising approach for treatment of PAH.

OBJECTIVES

This study sought to find a vaccine against endothelin-1 (ET-1) receptor type A (ETAR) for treating PAH.

METHODS

The ETRQβ-002 vaccine was screened and the specific antibodies against epitope ETR-002 belonging to the second extracellular loop of ETAR (including the polyclonal and monoclonal antibody) were produced. The effect of the antibodies on Ca²⁺-dependent signal transduction events was investigated. In vivo, ETRQβ-002 vaccine was used to vaccinate monocrotaline (MCT)- and Sugen/hypoxia-induced pulmonary hypertension animals. The monoclonal antibody (mAb) against ETR-002 was also injected into the PAH animals. The effect of ETRQβ-002 vaccine on pulmonary hypertension and remodeling of pulmonary arterioles and right ventricle (RV) was carefully evaluated. Further, the possible immune-mediated damage was detected in normal vaccinated animals.

RESULTS

ETR-002 peptide has perfect immunogenicity and ETRQβ-002 vaccine could induce strong antibody production. In vitro, the anti-ETR-002 antibody bound to ETAR and inhibited Ca²⁺-dependent signal transduction events, including extracellular signal-regulated kinase phosphorylation and elevation of intracellular Ca²⁺ concentration induced by ET-1. In vivo, both ETRQβ-002 vaccine and the mAb significantly decreased the RV systolic pressure up to 20 mm Hg and 10 mm Hg in MCT-exposed rats and Sugen/hypoxia-exposed mice, respectively. Also, ETRQβ-002 vaccine/mAb obviously ameliorated pathological remodeling of pulmonary arterioles and hypertrophy of the RV in PAH animals. Additionally, no significant immune-mediated damage was detected in vaccinated animals.

CONCLUSIONS

ETRQβ-002 vaccine/mAb attenuated remodeling of pulmonary arterioles and RV in MCT- and Sugen/hypoxia-induced PAH animals and decreased RV systolic pressure effectively through diminishing the pressure response and inhibiting signal transduction initiated by ET-1. ETRQβ-002 vaccine/mAb may provide a novel and promising method for PAH treatment.

Help-seeking patterns and funding strategies in patients with pulmonary arterial hypertension on phosphodiesterase-5 inhibitors: an orphan disease with effective but costly treatment

INTRODUCTION

Pulmonary arterial hypertension (PAH) is associated with high medical and pharmaceutical costs. Phosphodiesterase type 5 (PDE5) inhibitors have been found to be beneficial but costly. They are not subsidised in Singapore except via the Medication Assistance Fund (MAF) Plus scheme. In this study, we described the help-seeking behaviour of patients and funding strategies for Singaporean patients on PDE5 inhibitors in our registry.

METHODS

We consecutively recruited all patients with PAH who presented to our pulmonary hypertension specialty centre between 1 January 2003 and 29 December 2016. Singaporean patients on PDE5 inhibitors were included. Data recorded and analysed for this study included baseline demographics, whether the patients received MAF Plus funding, percentage of funding, and any additional source of subsidies.

RESULTS

114 (77.0%) of 148 patients in the registry were Singapore citizens on PDE5 inhibitors. 75 (65.8%) of these 114 patients had been seen by a medical social worker, of whom 16 were on MAF Plus funding. 14 of the remaining 59 patients were subsidised by MediFund, whereas the remainder were self-paying. 30 (26.3%) patients in total were on some form of subsidy, and 28 (24.6%) patients were on combination therapy. Of this group, nine were receiving MAF Plus subsidies.

CONCLUSION

Fewer than expected patients were found to be receiving drug subsidies for PAH. This was partly due to insufficient referrals and lack of requests for financial assistance. Patients on combination therapy had greater financial challenges. This study should spur us on to study funding gaps further and address them.

The apelinergic system: a perspective on challenges and opportunities in cardiovascular and metabolic disorders

The apelinergic pathway has been generating increasing interest in the past few years for its potential as a therapeutic target in several conditions associated with the cardiovascular and metabolic systems. Indeed, preclinical and, more recently, clinical evidence both point to this G protein-coupled receptor as a target of interest in the treatment of not only cardiovascular disorders such as heart failure, pulmonary arterial hypertension, atherosclerosis, or septic shock, but also of additional conditions such as water retention/hyponatremic disorders, type 2 diabetes, and preeclampsia. While it is a peculiar system with its two classes of endogenous ligand, the apelins and Elabela, its intricacies are a matter of continuing investigation to finely pinpoint its potential and how it enables crosstalk between the vasculature and organ systems of interest. In this perspective article, we first review the current knowledge on the role of the apelinergic pathway in the above systems, as well as the associated therapeutic indications and existing pharmacological tools. We also offer a perspective on the challenges and potential ahead to advance the apelinergic system as a target for therapeutic intervention in several key areas.

Identification of Emetine as a Therapeutic Agent for Pulmonary Arterial Hypertension

Objective:

Excessive proliferation and apoptosis resistance are special characteristics of pulmonary artery smooth muscle cells (PASMCs) in pulmonary arterial hypertension (PAH). However, the drugs in clinical use for PAH target vascular dilatation, which do not exert adequate effects in patients with advanced PAH. Here, we report a novel therapeutic effect of emetine, a principal alkaloid extracted from the root of ipecac clinically used as an emetic and antiprotozoal drug.

Approach and Results:

We performed stepwise screenings for 5562 compounds from original library. First, we performed high-throughput screening with PASMCs from patients with PAH (PAH-PASMCs) and found 80 compounds that effectively inhibited proliferation. Second, we performed the repeatability and counter assay. Finally, we performed a concentration-dependent assay and found that emetine inhibits PAH-PASMC proliferation. Interestingly, emetine significantly reduced protein levels of HIFs (hypoxia-inducible factors; HIF-1α and HIF-2α) and downstream PDK1 (pyruvate dehydrogenase kinase 1). Moreover, emetine significantly reduced the protein levels of RhoA (Ras homolog gene family, member A), Rho-kinases (ROCK1 and ROCK2 [rho-associated coiled-coil containing protein kinases 1 and 2]), and their downstream CyPA (cyclophilin A), and Bsg (basigin) in PAH-PASMCs. Consistently, emetine treatment significantly reduced the secretion of cytokines/chemokines and growth factors from PAH-PASMCs. Interestingly, emetine reduced protein levels of BRD4 (bromodomain-containing protein 4) and downstream survivin, both of which are involved in many cellular functions, such as cell cycle, apoptosis, and inflammation. Finally, emetine treatment ameliorated pulmonary hypertension in 2 experimental rat models, accompanied by reduced inflammatory changes in the lungs and recovered right ventricular functions.

Conclusions:

Emetine is an old but novel drug for PAH that reduces excessive proliferation of PAH-PASMCs and improves right ventricular functions.

Risk Reduction and Right Heart Reverse Remodeling by Upfront Triple Combination Therapy in Pulmonary Arterial Hypertension

BACKGROUND

Combinations of therapies are currently recommended for patients with severe pulmonary arterial hypertension (PAH), and excellent results have been reported with triple upfront combination of these drugs. We evaluated the effects of this approach on right ventricular (RV) function and outcome in patients with severe PAH.

METHODS

Twenty-one patients (age, 44 ± 15 years) with newly diagnosed high-risk idiopathic PAH that was nonreversible by the inhalation of nitric oxide were treated upfront with a combination of ambrisentan, tadalafil, and subcutaneous treprostinil between 2014 and 2018. Clinical evaluation, World Health Organization functional class, 6-min walk distance, biomarkers, echocardiography, and right-sided heart catheterization data were recorded at baseline and during follow-up.

RESULTS

At a median follow-up of 2 years, all patients were still alive. The Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management score decreased from 10 ± 1 to 5 ± 1, right-sided atrial pressure decreased from 13 ± 3 to 5 ± 2 mm Hg, mean pulmonary artery pressure decreased from 60 ± 9 to 42 ± 5 mm Hg, pulmonary vascular resistance (PVR) decreased from 16.4 ± 4.4 to 5.5 ± 1.3 Wood units, N-terminal pro-brain natriuretic peptide decreased from 3,379 ± 1,921 to 498 ± 223 pg/mL, and World Health Organization functional class decreased from 3.4 ± 0.5 to 2.0 ± 0.4 (all P < .001). Cardiac index increased from 1.8 ± 0.3 to 3.5 ± 0.8 L/min/m² and 6-min walk distance increased from 158 ± 130 to 431 ± 66 m (both P < .001). Echocardiography showed decreased right-sided atrial and RV areas, improved left ventricular eccentricity index, and increased fractional area change (all P < .001) in proportion to treatment-induced decrease in PVR.

CONCLUSIONS

Triple upfront combination therapy with ambrisentan, tadalafil, and subcutaneous treprostinil in severe nonreversible PAH is associated with considerable clinical and hemodynamic improvement and right-sided heart reverse remodeling.

The Efficacy and Safety of Aerosolized Iloprost in Pulmonary Arterial Hypertension: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis was conducted to investigate the efficacy and safety of the chronic administration of aerosolized iloprost for pulmonary arterial hypertension (PAH).

METHODS

All the relevant studies were obtained from three databases, namely, PubMed, Web of Science and the Cochrane Library, from the inception of each database to June 1, 2018. In our study, chronic treatment was defined as a period lasting at least 3 months. The rate of each event was analyzed by SPSS as a percentage with 95% confidence intervals (CIs). For the meta-analysis, a randomized effect model or a fixed effect model was applied according to the results of the heterogeneity test.

RESULTS

Ten studies were included in this study, with a total of 370 patients treated with inhaled iloprost, including 214 in five randomized controlled trials and 156 in five prospective clinical trials. Among the patients who received inhaled iloprost, there was a significant improvement in the 6-min walk distance (6MWD) in the short-medium and prolonged treatment groups. Notably, the functionality improved by at least 1 class in 48.7% of the treated patients. In all the pooled studies, the estimated 3-month, 6-month, 1-year and 2-year event-free survival rates were 96.6%, 92.3%, 62.6% and 39.6%, respectively. In addition, there were eight adverse drug responses.

CONCLUSION

In this systematic review and meta-analysis, inhaled iloprost has been shown to be a safe and well-tolerated agent for PAH in the first 3 months after diagnosis. If used for a prolonged period, aerosol iloprost monotherapy could contribute to an unsatisfactory improvement in vascular remodeling and even a decreased event-free survival rate.

Pulmonary Arterial Hypertension and Therapeutic Interventions

Pulmonary hypertension is an uncommon disease that carries a significant morbidity and mortality. Pulmonary arterial hypertension is a subtype of pulmonary hypertension that describes a group of disease entities that lead to an elevation in precapillary pulmonary artery pressure. Despite advances in the diagnosis and treatment of pulmonary arterial hypertension, it remains a difficult disease to recognize and manage. In this review article, we will discuss the definition and diagnosis of pulmonary arterial hypertension. Additionally, we will discuss the ever-expanding management options, their mechanisms and strategies, including combination therapy and the most recent advances and future directions.

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.

Clinical and hemodynamic benefit of macitentan and riociguat upfront combination in patients with pulmonary arterial hypertension

In this open-label study, we evaluated the effect of upfront macitentan and riociguat combination in newly diagnosed pulmonary arterial hypertension (PAH) patients. In 15 consecutive PAH patients, we collected clinical and hemodynamic data at baseline, visit 1 (median 4 months) and visit 2 (median 12 months). Survival and transplantation status were analyzed over 36 months. Statistical analysis included student t-test and 95% confidence interval (CI) ( t-statistic or Clopper-Pearson). Kaplan-Meier was used to estimate survival rate. There were 11/15 women (mean age 56 years), in World Health Organization (WHO) functional class (FC) III ( n = 14) or IV ( n = 1). The 6 min walk distance increased from 281.6 m (baseline) to 315.7 m (visit 1) and visit 2 (313.9 m), representing a 34- and 32-m change ( P < 0.05), respectively, associated with Borg score improvements. Brain natriuretic peptide decreased: 318.2 pg/mL (baseline) to 122.0 pg/mL (visit 1) and 98.6 pg/mL (visit 2) ( P < 0.05). WHO FC improved in eight patients (53%, 95% CI 27%-79%). Pulmonary vascular resistance (9.2 to 5.7 Wood Units) and mean pulmonary artery pressure (47.3 to 38.9 mmHg) decreased; cardiac index increased (2.3 to 3.0 L/min/m²) (baseline to visit 2, all P < 0.05). All patients had intermediate and high risk score (baseline); at 1-year follow-up, dual therapy led to reduction to low risk score in 7/15 (47%) patients. There were no unexpected or serious side effects. Three patients died due to unrelated causes; one patient received a lung transplant. Transplant-free survival rate (36 months) was 85%. Preliminary evidence is provided for effectiveness of initial macitentan and riociguat combination therapy in PAH.

＜Editors' Choice＞ Pulmonary Hypertension: Diagnosis, Management, and Treatment

Pulmonary hypertension (PH) is a hemodynamic state that is characterized by a resting mean pulmonary artery pressure ≧ 25 mmHg. The common forms of PH are pulmonary arterial hypertension (PAH), chronic thromboembolic pulmonary hypertension (CTEPH), PH caused by left-heart disease, and PH due to lung disease. Previously regarded as untreatable, the treatment of PAH has dramatically advanced since the introduction of the drug epoprostenol in 1999, with three-year survival rates improving from 30%-40% to over 85%. Drugs available for the specific treatment of PAH include endothelin-receptor antagonists, phosphodiesterase type 5 inhibitors, soluble guanylate cyclase stimulators, prostacyclin analogs, and prostacyclin-receptor agonists. In the past decade, management and treatment of CTEPH have also improved. While pulmonary endarterectomy used to be the only option for the treatment of CTEPH, newer treatments include a soluble guanylate cyclase stimulator, which has proven to be an efficacious targeted therapy. Other cases benefit from balloon pulmonary angioplasty.

Analysis of Biphasic Right Ventricular Outflow Doppler Waveform in Patients with Pulmonary Hypertension

Pulmonary hypertension (PH) with pulmonary vascular disease (PVD) is a progressive and debilitating disease associated with increased pulmonary vascular resistance (PVR). Biphasic right ventricular outflow tract (RVOT) Doppler flow is frequently seen in severe PH patients with PVD. In association with hemodynamics, the precise analysis of biphasic RVOT Doppler flow (RVDF) has not been fully elucidated. Therefore, the purpose of the present study is to analyze the relation between the hemodynamics and indices of biphasic RVDF in PH patients with PVD.Seventy PH patients with biphasic RVDF were analyzed. All patients underwent transthoracic echocardiography and right heart catheterization. For the analysis of biphasic RVDF, the early waveform was determined as P₁ while the late waveform was determined as P₂. For each P₁ and P₂, the duration (D, seconds) and peak flow velocity (PFV, in m/second) were measured.P₁D and P₂PFV were significantly correlated with PVR (P₁D: r = -0.542, P < 0.0001, P₂PFV: r = -0.513, P < 0.0001). Therefore, we propose a novel RVDF formula for estimation of PVR, as follows. PVR = 26 - 77 × P₁D - 14 × P₂PFV. The PVR could be estimated by this proposed formula (r = 0.649, P < 0.0001), which is derived from one Doppler image only unlike previously used PVR prediction formula.P₁D and P₂PFV were associated with PVR. Moreover, this simple RVDF formula proposed herein can estimate PVR in PH patients with PVD.

Pathophysiology of the right ventricle and of the pulmonary circulation in pulmonary hypertension: an update

The function of the right ventricle determines the fate of patients with pulmonary hypertension. Since right heart failure is the consequence of increased afterload, a full physiological description of the cardiopulmonary unit consisting of both the right ventricle and pulmonary vascular system is required to interpret clinical data correctly. Here, we provide such a description of the unit and its components, including the functional interactions between the right ventricle and its load. This physiological description is used to provide a framework for the interpretation of right heart catheterisation data as well as imaging data of the right ventricle obtained by echocardiography or magnetic resonance imaging. Finally, an update is provided on the latest insights in the pathobiology of right ventricular failure, including key pathways of molecular adaptation of the pressure overloaded right ventricle. Based on these outcomes, future directions for research are proposed.

State of the art and research perspectives in pathophysiology of the right ventricle and of the pulmonary circulation in pulmonary hypertension with theoretical and practical aspectshttp://ow.ly/18v830mgLiP

Advanced Pulmonary Hypertension Due to Congenital Double-shunt Successfully Treated with Surgical Repair and Up-front Combination Therapy

This case report concerns a 22-year-old woman with large patent ductus arteriosus and atrial septal defect. She was referred to our hospital because of exertional dyspnea and was revealed to have advanced pulmonary arterial hypertension (PAH) with a mean pulmonary arterial pressure (PAP) of 79 mmHg. Although both shunts had bidirectional flow, based on the results of acute pulmonary vasoreactive testing, one-stage surgical closure was performed followed by up-front combination therapy for post-operative pulmonary hypertensive crisis and residual PAH. At 14 months after the surgery, her symptoms were markedly improved, and her mean PAP had dramatically decreased to 13 mmHg.

Risk stratification and medical therapy of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) remains a severe clinical condition despite the availability over the past 15 years of multiple drugs interfering with the endothelin, nitric oxide and prostacyclin pathways. The recent progress observed in medical therapy of PAH is not, therefore, related to the discovery of new pathways, but to the development of new strategies for combination therapy and on escalation of treatments based on systematic assessment of clinical response. The current treatment strategy is based on the severity of the newly diagnosed PAH patient as assessed by a multiparametric risk stratification approach. Clinical, exercise, right ventricular function and haemodynamic parameters are combined to define a low-, intermediate- or high-risk status according to the expected 1-year mortality. The current treatment algorithm provides the most appropriate initial strategy, including monotherapy, or double or triple combination therapy. Further treatment escalation is required in case low-risk status is not achieved in planned follow-up assessments. Lung transplantation may be required in most advanced cases on maximal medical therapy.

Risk stratification and medical therapy of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) remains a severe clinical condition despite the availability over the past 15 years of multiple drugs interfering with the endothelin, nitric oxide and prostacyclin pathways. The recent progress observed in medical therapy of PAH is not, therefore, related to the discovery of new pathways, but to the development of new strategies for combination therapy and on escalation of treatments based on systematic assessment of clinical response. The current treatment strategy is based on the severity of the newly diagnosed PAH patient as assessed by a multiparametric risk stratification approach. Clinical, exercise, right ventricular function and haemodynamic parameters are combined to define a low-, intermediate- or high-risk status according to the expected 1-year mortality. The current treatment algorithm provides the most appropriate initial strategy, including monotherapy, or double or triple combination therapy. Further treatment escalation is required in case low-risk status is not achieved in planned follow-up assessments. Lung transplantation may be required in most advanced cases on maximal medical therapy.