Challenges and Special Aspects of Pulmonary Hypertension in Middle- to Low-Income Regions: JACC State-of-the-Art Review

Prognostic and diagnostic utility of interleukin-6 in pediatric pulmonary arterial hypertension - a case-control study

Pulmonary arterial hypertension (PAH) in pediatrics is a progressive disease with significant vascular remodeling, right sided heart failure, and death if left untreated. Elevated interleukin-6 (IL-6) level in PAH patients is taken as an independent predictor of adverse outcome including mortality. The aim of this study was to investigate and compare serum levels of IL-6 in children with PAH and healthy matched controls, and correlate between IL-6 and degree of PAH, as well as mortality. IL-6 was measured by ELISA in serum samples in 40 children with PAH (age 1-12 years) and 40 age and sex-matched healthy controls. There was a statistically significant increase in IL-6 level among PAH cases compared with the controls (1.85 ng/L vs 1.30 ng/L, p-value = 0.004). IL-6 at cut off point 1.45 ng/L significantly predict pulmonary hypertension in children (AUC = 0.685, 75% sensitivity, and 65% specificity with p = 0.002). There was no statistically significant association between IL-6 level and degree of PAH (p = 0.218). There was no statistically significant association between IL-6 level and mortality (p = 0.662).    Conclusion: IL-6 significantly predict PAH in pediatrics but there is no association between IL-6 level and degree of PAH or mortality. IL-6 may provide a less costly and less invasive method for disease detection. What is Known: • Definitive diagnosis of PAH is made by right heart catheterization, while echocardiography is the gold standard for tracking the course of the disease. What is New: • It was assumed that children with a diagnosis of PAH would have higher serum IL-6 levels than controls. Furthermore, an adverse relationship between the blood IL-6 level and PPAH was predicted.

Outcomes of patients with elevated pulmonary artery systolic pressure on echocardiography due to chronic lung diseases

BACKGROUND

Pulmonary hypertension is associated with increased mortality, and lung diseases are the second most common cause of pulmonary hypertension. We aimed to evaluate the prognostic value of echocardiography in low-middle income countries where right heart catheterization is difficult to perform.

METHODS

This retrospective chart review study included adult patients hospitalized from June 2012 to May 2021, with a pulmonary artery systolic pressure (PASP) of ≥35 mmHg on echocardiography. The control arm consisted of patients with similar lung diseases who did not have an elevated PASP.

RESULTS

The study and control arm consisted of 128 patients each, with both groups having similar lung diseases. Obesity hypoventilation syndrome was the most common etiology of elevated PASP (28.1 %), followed by pulmonary embolism (20.3 %). The overall 1-year mortality of the study cohort, after diagnosis of elevated PASP, was 20.3 %. The control cohort with normal PASP had a 1-year mortality of 4.7 %. In the study cohort, patients with bronchiectasis had the highest cause-specific 1-year mortality (45.5 %). In the normal PASP cohort, the highest cause-specific 1-year mortality was observed in patients with interstitial lung disease (13.0 %). One-year hospital readmission was observed in 46.9 % and 33.6 % of patients in the study and control arms, respectively. On multivariate analysis, increased odds of 1-year mortality were observed in patients with elevated PASP, patients with 1-year hospital readmission, and in patients with interstitial lung disease or bronchiectasis.

CONCLUSION

Elevated PASP on echocardiography may be a prognostic factor for mortality in patients with chronic lung diseases.

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.

Real-world evidence to advance knowledge in pulmonary hypertension: Status, challenges, and opportunities. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative's Real-world Evidence Working Group

This manuscript on real-world evidence (RWE) in pulmonary hypertension (PH) incorporates the broad experience of members of the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative Real-World Evidence Working Group. We aim to strengthen the research community's understanding of RWE in PH to facilitate clinical research advances and ultimately improve patient care. Herein, we review real-world data (RWD) sources, discuss challenges and opportunities when using RWD sources to study PH populations, and identify resources needed to support the generation of meaningful RWE for the global PH community.

Global leadership in paediatric and congenital cardiac care: education and empowerment to improve outcomes in low- and middle-income countries - an interview with Krishna Kumar, MD, DM FAHA

Dr Krishna Kumar is the focus of our sixth in a series of interviews in Cardiology in the Young entitled, "Global Leadership in Paediatric and Congenital Cardiac Care." Dr Kumar was born in Raurkela, India. He attended medical school at Maulana Azad Medical College in New Delhi, graduating in 1984. Dr Kumar then went on to complete internal medicine, emergency medicine, and adult cardiology training at All India Institute of Medical Sciences in 1988, 1989, and 1990, respectively. He then pursued paediatric cardiology training at Harvard Medical School in Boston, MA, USA. Dr Kumar began his clinical position as a paediatric cardiologist at Amrita Institute of Medical Sciences in Kochi, Kerala, India.During his impressive career, Dr Kumar has made significant contributions to educational advancement, research and innovation, public health advocacy, and clinical care. Dr Kumar is credited for distinguishing paediatric cardiology as a distinct subspecialty in India. He was a founding member of the Pediatric Cardiology Society of India and the original editor of the society's academic journal. Recognising the deficit of paediatric cardiology-trained physicians in low- and middle-income countries, Dr Kumar helped establish formal structured training programmes for paediatric cardiology in India. More recently, he established the Children's HeartLink Fellowships in paediatric cardiac sciences at Amrita Institute of Medical Sciences in Kochi and Institut Jantung Negara in Malaysia. Through educational programmes, Dr Kumar has taught countless caregivers and paediatricians, in India and neighbouring countries, the early identification and management of children with CHD. Dr Kumar has established a premier paediatric heart programme at Amrita Institute of Medical Sciences. As department Chief, he emphasises the importance of teamwork, advocacy, and continuous quality improvement. He has developed numerous low-cost strategies for the management of CHD. He has established large community-based studies on rheumatic heart disease and CHD in South India. Dr Kumar's focus on advocacy and policy change in India has made a substantial impact on early identification and treatment of CHD in the subcontinent. He has made a global impact on the care of paediatric cardiology patients through his educational programmes, research and innovation, large-scale research registries, and advocacy for public health policy changes. He is an incredibly humble and generous leader, and his patients and community are the source of his unending motivation.

Early and long-term results of ventricular septal defect repair in children with severe pulmonary hypertension and elevated pulmonary vascular resistance by the double or traditional patch technique

OBJECTIVES

In upper-income countries, infants undergo low-risk ventricular septal defect (VSD) repair. Children in low- and middle-income countries frequently present at older ages with elevated pulmonary vascular resistance (PVR) and pulmonary arterial hypertension (PAH). Expensive interventions for pulmonary hypertensive crisis are not available, and children are often denied an operation due to the mortality risk. We report our early and late experiences with these patients who underwent VSD closure by traditional patch (TP) or double patch (DP) techniques.

METHODS

We extracted data from patients with VSD and PAH who underwent VSD closure operations from 1996 to 2016. Information regarding cardiac catheterizations, operations, time in the intensive care unit and follow-up information was found. We identified 129 children and analysed the differences between the TP (89/129) and the DP (40/129) in unidirectional groups. After 2005, the patients were pretreated with sildenafil 3 months before catheterization.

RESULTS

The TP group was younger (P  < 0.001). Hospital mortality (2.5%, DP; 10.1%,TP) was not significantly different (P  = 0.17) between the 2 groups despite significant differences in baseline PVR, PVR/systemic vascular resistance and the number of children with a saturation less than 90%. The long-term survival and regression of PAH were better in the DP group (survival over 97% vs 93% in the TP group). Moreover, 61% of children with DP and 75% of those with TP had normal to mild elevations in pulmonary artery pressures at the last follow-up examination (P  = 0.046).

CONCLUSIONS

The DP operation is a low-risk procedure. Moreover, the long-term outcome with the use of this technique in high-risk patients with VSD and high PVR and PAH is favourable with respect to survival and showed a decrease in PAH at the last follow-up.

The Clinical and Cost Utility of Cardiac Catheterizations in Infants with Bronchopulmonary Dysplasia

OBJECTIVE

To evaluate the cost-utility of catheterization-obligate treatment in preterm infants with pulmonary hypertension, as compared with empiric initiation of sildenafil based on echocardiographic findings alone.

STUDY DESIGN

A Markov state transition model was constructed to simulate the clinical scenario of a preterm infant with echocardiographic evidence of pulmonary hypertension associated with bronchopulmonary dysplasia (BPD) and without congenital heart disease under consideration for the initiation of pulmonary vasodilator therapy via one of two modeled treatment strategies-empiric or catheterization-obligate. Transitional probabilities, costs and utilities were extracted from the literature. Forecast quality-adjusted life-years was the metric for strategy effectiveness. Sensitivity analyses for each variable were performed. A 1000-patient Monte Carlo microsimulation was used to test the durability of our findings.

RESULTS

The catheterization-obligate strategy resulted in an increased cost of $10 778 and 0.02 fewer quality-adjusted life-years compared with the empiric treatment strategy. Empiric treatment remained the more cost-effective paradigm across all scenarios modeled through one-way sensitivity analyses and the Monte Carlo microsimulation (cost-effective in 98% of cases).

CONCLUSIONS

Empiric treatment with sildenafil in infants with pulmonary hypertension associated with BPD is a superior strategy with both decreased costs and increased effectiveness when compared with catheterization-obligate treatment. These findings suggest that foregoing catheterization before the initiation of sildenafil is a reasonable strategy in preterm infants with uncomplicated pulmonary hypertension associated with BPD.

Current Status and Barriers in Pulmonary Hypertension Care Delivery in India: A Qualitative Analysis

Although pulmonary hypertension (PH) is widely prevalent in India, care delivery for this condition has unique challenges in a lower middle‐income country (LMIC). To describe care delivery for patients with PH and associated barriers in India. We interviewed physicians across eight healthcare systems in India about PH clinical care using semi‐structured enquiries to understand care delivery and associated challenges in their specific practice as well as the associated health system. Qualitative analysis was performed using content analysis methodology. Physicians reported that common causes for PH in their practice were rheumatic mitral valve disease, coronary artery disease, and congenital heart disease (CHD). No center had a dedicated PH program. Only one center had a specific protocol for PH management. Diagnostic evaluations were limited, and right heart catheterizations were recommended for patients with CHD. Pulmonary vasodilator therapy was used for severe symptoms or markers of severe disease. Agents used to treat PH were widely variable across physicians and prostacyclins are unavailable in India. Barriers included limited training in PH for physicians, lack of consensus guidelines for PH specific to LMIC, and lack of financial incentives for health care systems to organize dedicated PH programs. Other barriers included poor patient health literacy and socioeconomic barriers that limit ability to test and treat PH. PH care delivery in India is variable with widely differing clinical practices. Dedicated training in PH management and establishing guidelines specific to LMIC like India can form the first step forward.

Pulmonary Hypertension in Pregnancy: Challenges and Solutions

Pulmonary hypertension (PH) is a heterogeneous disease characterized by an elevated mean pulmonary artery pressure of 20 mm Hg or above. PH is a prevalent condition among women of reproductive age and is linked with poor prognosis during pregnancy. Pregnancy is a stressful event and complicates the management and prognosis in patients with PH. In this review, we discuss the pathogenesis, clinical presentation as well as therapeutic options for PH during pregnancy. We also highlight knowledge gaps to guide future research.

Characteristics, goal-oriented treatments and survival of pulmonary arterial hypertension in China: Insights from a national multicentre prospective registry

BACKGROUND AND OBJECTIVE

Nationally representative reports on the characteristics and long-term survival of pulmonary arterial hypertension (PAH) from developing countries are scarce. The applicability of the current main risk stratifications and the longitudinal changes in goal-oriented treatments have yet to be elucidated in real-world settings. Therefore, we aimed to provide insights into the characteristics, goal-oriented treatments and survival of PAH in China and to explore the applicability of the main risk stratifications in our independent cohort.

METHODS

PAH patients were consecutively enrolled from a national prospective multicentre registry. Data on baseline, follow-up re-evaluation and therapeutic changes were collected.

RESULTS

A total of 2031 patients were enrolled, with congenital heart disease (CHD)-PAH (45.2%) being the most common aetiology. The mean age was 35 ± 12 years, and 76.2% were females. At baseline, approximately 20% of the patients with intermediate or high risk received combination treatment. At follow-up, approximately half of the re-evaluated patients did not achieve low-risk profiles, and even among patients who received combination therapy at baseline, 4% of them still worsened. The rate of combination therapy increased significantly from 6.7% before 2015 to 35.5% thereafter. The main risk assessment tools demonstrated good performance for predicting survival both at baseline and at follow-up.

CONCLUSION

Chinese PAH patients show both similar and distinct features compared to other countries. Current main risk stratifications can significantly discriminate patients at different risk levels. There were still many patients not achieving low-risk profiles at follow-up, indicating more aggressive treatment should be implemented to optimize the goal-oriented treatment strategy.

Interplay of Low-Density Lipoprotein Receptors, LRPs, and Lipoproteins in Pulmonary Hypertension

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LDLR regulates oxidized LDL level, which is increased in lung and blood from PAH patients.

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LRP1 preserving vascular homeostasis is decreased in PAH patients.

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LRP5/6 regulating Wnt signaling is upregulated in PH.

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The LRP8 (aka ApoER2) ligand ApoE protects from PAH.

The low-density lipoprotein receptor (LDLR) gene family includes LDLR, very LDLR, and LDL receptor–related proteins (LRPs) such as LRP1, LRP1b (aka LRP-DIT), LRP2 (aka megalin), LRP4, and LRP5/6, and LRP8 (aka ApoER2). LDLR family members constitute a class of closely related multifunctional, transmembrane receptors, with diverse functions, from embryonic development to cancer, lipid metabolism, and cardiovascular homeostasis. While LDLR family members have been studied extensively in the systemic circulation in the context of atherosclerosis, their roles in pulmonary arterial hypertension (PAH) are understudied and largely unknown. Endothelial dysfunction, tissue infiltration of monocytes, and proliferation of pulmonary artery smooth muscle cells are hallmarks of PAH, leading to vascular remodeling, obliteration, increased pulmonary vascular resistance, heart failure, and death. LDLR family members are entangled with the aforementioned detrimental processes by controlling many pathways that are dysregulated in PAH; these include lipid metabolism and oxidation, but also platelet-derived growth factor, transforming growth factor β1, Wnt, apolipoprotein E, bone morpohogenetic proteins, and peroxisome proliferator-activated receptor gamma. In this paper, we discuss the current knowledge on LDLR family members in PAH. We also review mechanisms and drugs discovered in biological contexts and diseases other than PAH that are likely very relevant in the hypertensive pulmonary vasculature and the future care of patients with PAH or other chronic, progressive, debilitating cardiovascular diseases.

Prevalence, incidence, and survival of pulmonary arterial hypertension: A systematic review for the global burden of disease 2020 study

Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the pulmonary arterioles as a result of remodeled blood vessels. We sought all available epidemiologic data on population‐based prevalence, incidence, and 1‐year survival of PAH as part of the Global Burden of Disease Study. We performed a systematic review searching Global Index Medicus (GIM) for keywords related to PAH between 1980 and 2021 and identified population‐representative sources of prevalence, incidence, and mortality for clinically diagnosed PAH. Of 6772 articles identified we found 65 with population‐level data: 17 for prevalence, 17 for incidence, and 58 reporting case fatality. Reported prevalence ranged from 0.37 cases/100,000 persons in a referral center of French children to 15 cases/100,000 persons in an Australian study. Reported incidence ranged from 0.008 cases/100,000 person‐years in Finland, to 1.4 cases/100,000 person‐years in a retrospective chart review at a clinic in Utah, United States. Reported 1‐year survival ranged from 67% to 99%. All studies with sex‐specific estimates of prevalence or incidence reported higher levels in females than males. Studies varied in their size, study design, diagnostic criteria, and sampling procedures. Reported PAH prevalence, incidence, and mortality varied by location and study. Prevalence ranged from 0.4 to 1.4 per 100,000 persons. Harmonization of methods for PAH registries would improve efforts at disease surveillance. Results of this search contribute to ongoing efforts to quantify the global burden of PAH.

Pulmonary Hypertension Registry of Kerala, India (PRO-KERALA): One-year outcomes

BACKGROUND

Short term outcomes of patients with pulmonary hypertension are not available from low and middle-income countries including India.

METHODS

We conducted a prospective study of 2003 patients with pulmonary hypertension, from 50 centres (PROKERALA) in Kerala, who were followed up for one year. Pulmonary hypertension (PH) was mainly diagnosed on the basis of Doppler echocardiography. The primary outcome was a composite end-point of all-cause death and hospital admission for heart failure. All cause hospitalisation events constituted the secondary outcome.

RESULTS

Mean age of study population was 56 ± 16 years. Group 1 and Group 2 PH categories constituted 21.2% and 59% of the study population, respectively. Nearly two-thirds (65%) of the study participants had functional class II symptoms. 31% of Group 1 PH patients were on specific vasodilator drugs.In total, 83 patients (4.1%) died during the one-year follow-up period. Further, 1235 re-hospitalisation events (61.7%) were reported. In the multivariate model, baseline NYHA class III/IV (OR 1.87, 95% C.I. 1.35-2.56), use of calcium channel blockers (OR 0.18, 95% C.I. 0.04-0.77), vasodilator therapy (OR 0.5, 95% C.I. 0.28-0.87) and antiplatelet agents (OR 1.80, 95% C.I. 1.29-2.51) were associated with primary composite outcome at one-year (p < 0.05).

CONCLUSION

In the PROKERALA registry, annual mortality rate was 4%. More than half of the patients reported re-hospitalisation events on follow up. Uptake of guideline directed therapies were suboptimal in the study population. Quality improvement programmes to improve guideline directed therapy may improve clinical outcomes of PH patients in India.

Pulmonary Hypertension in Children across Africa: The Silent Threat

Pulmonary hypertension (PH) is a complex puzzle in Africa, especially among children who present with a cocktail of issues including recurrent pulmonary infections, unoperated congenital heart disease, and advanced rheumatic heart disease. Sickle cell anemia and neonatal complications of transiting from fetal circulation also contribute to the burden of pulmonary hypertension. Mortality from pulmonary arterial hypertension (PAH) remains high in Africa (18-21%), claiming sufferers in the first 6 months after diagnosis. Unfortunately, PH remains underreported in sub-Saharan Africa since many centers lack the capacity to diagnose and confirm it by the recommended gold standard, right heart catheterization. The unresolved burden of unoperated congenital heart lesions and rheumatic heart disease, among other preventable causes, stand out as major causes of PH in African children. This paper highlights pediatric PAH as a result of major gaps in care and illustrates the need for its prevention as well as for the promotion of research into the most important drivers, to prevent premature mortality in the continent.

Iron Metabolism and Idiopathic Pulmonary Arterial Hypertension: New Insights from Bioinformatic Analysis

Idiopathic pulmonary arterial hypertension (IPAH) is a rare vascular disease with a poor prognosis, and the mechanism of its development remains unclear. Further molecular pathology studies may contribute to a comprehensive understanding of IPAH and provide new insights into diagnostic markers and potential therapeutic targets. Iron deficiency has been reported in 43-63% of patients with IPAH and is associated with reduced exercise capacity and higher mortality, suggesting that dysregulated iron metabolism may play an unrecognized role in influencing the development of IPAH. In this study, we explored the regulatory mechanisms of iron metabolism in IPAH by bioinformatic analysis. The molecular function of iron metabolism-related genes (IMRGs) is mainly enriched in active transmembrane transporter activity, and they mainly affect the biological process of response to oxidative stress. Ferroptosis and fluid shear stress and atherosclerosis pathways may be the critical pathways regulating iron metabolism in IPAH. We further identified 7 key genes (BCL2, GCLM, MSMO1, SLC7A11, SRXN1, TSPAN5, and TXNRD1) and 5 of the key genes (BCL2, MSMO1, SLC7A11, TSPAN5, and TXNRD1) as target genes may be regulated by 6 dysregulated miRNAs (miR-483-5p, miR-27a-3p, miR-27b-3p, miR-26b-5p, miR-199a-5p, and miR-23b-3p) in IPAH. In addition, we predicted potential IPAH drugs-celastrol and cinnamaldehyde-that target iron metabolism based on our results. These results provide insights for further definition of the role of dysregulated iron metabolism in IPAH and contribute to a deeper understanding of the molecular mechanisms and potential therapeutic targets of IPAH.

Treatment of adults with Eisenmenger syndrome-state of the art in the 21st century: a short overview

Eisenmenger syndrome (ES) develops in association with unrepaired, non-restrictive cardiac shunt lesions at the atrial, ventricular or arterial level over time. In developed countries, cardiac defects are being operated on in a timely manner, before pulmonary vascular disease develops. However, with rising immigration from underserved countries, we increasingly see patients with shunt lesions, that are not amenable for repair as pulmonary vascular disease has already established. ES describes a symptom complex and patients present with heterogeneous problems involving many organ systems (multisystem disorder). Care in tertiary specialist cardiac centers with access to multidisciplinary subspecialities is required. Central cyanosis with secondary erythrocytosis is one of the key features of patients with ES. Clinical consequences of longstanding hypoxia can lead to other organ complications, that involve other organs than the heart alone. Although ES patients have a better prognosis compared to other patients with pulmonary arterial hypertension, ES grossly affects quality of life and morbidity is frequent. Follow-up and care at specialist congenital heart disease centers is highly recommended to prevent, to early diagnose and to timely manage complications of ES. This is necessary to maintain functional capacity, decrease morbidity and increase life expectancy for these vulnerable patients. The leading reasons for mortality are sudden cardiac death, progressive heart failure, and infectious diseases. Various factors have been shown to be associated with mortality like decreased arterial oxygen saturation, functional class, impaired exercise tolerance, syncopal events, iron deficiency, presence of pre-tricuspid shunts, arrhythmias, increased (NT-pro) brain natriuretic peptide, echocardiographic variables of right ventricular dysfunction and hospitalization for heart failure. Although to date there is no causal therapy to reverse pulmonary vascular disease, a greater armamentarium of targeted therapies is available, which have been shown to be beneficial in patients with ES.

An Exaggerated Rise in Pulmonary Artery Pressure in a High-Altitude Dweller during the Cold Season

Chronic hypoxia-induced sustained pulmonary vasoconstriction and vascular remodeling lead to mild-to-moderate elevation of pulmonary artery pressure in high-altitude residents. However, in some of them, severe pulmonary hypertension may develop. Besides hypoxia, high-altitude residents also face other environmental challenges such as low ambient temperatures. We describe a case of a 49-year-old woman of Kyrgyz ethnicity with abnormally increased pulmonary artery pressure, revealed by Doppler echocardiography. Significantly elevated pulmonary artery pressure was detected in late winter and this was not associated with right ventricular hypertrophy or right ventricular dysfunction. Repeat echocardiography performed in late summer disclosed a significant attenuation of pulmonary artery pressure elevation, with no changes in right ventricular performance parameters. This case illustrates that, in susceptible individuals, long-term cold exposure could induce an abnormal pulmonary artery pressure rise, which can be reversed during warm seasons as in our patient. In certain circumstances, however, additional factors could contribute to a sustained pulmonary artery pressure increase and the development of persistent pulmonary hypertension, which often leads to right heart failure and premature death.

Generating Evidence From Contextual Clinical Research in Low- to Middle Income Countries: A Roadmap Based on Theory of Change

Along with inadequate access to high-quality care, competing health priorities, fragile health systems, and conflicts, there is an associated delay in evidence generation and research from LMICs. Lack of basic epidemiologic understanding of the disease burden in these regions poses a significant knowledge gap as solutions can only be developed and sustained if the scope of the problem is accurately defined. Congenital heart disease (CHD), for example, is the most common birth defect in children. The prevalence of CHD from 1990 to 2017 has progressively increased by 18.7% and more than 90% of children with CHD are born in Low and Middle-Income Countries (LMICs). If diagnosed and managed in a timely manner, as in high-income countries (HICs), most children lead a healthy life and achieve adulthood. However, children with CHD in LMICs have limited care available with subsequent impact on survival. The large disparity in global health research focus on this complex disease makes it a solid paradigm to shape the debate. Despite many challenges, an essential aspect of improving research in LMICs is the realization and ownership of the problem around paucity of local evidence by patients, health care providers, academic centers, and governments in these countries. We have created a theory of change model to address these challenges at a micro- (individual patient or physician or institutions delivering health care) and a macro- (government and health ministries) level, presenting suggested solutions for these complex problems. All stakeholders in the society, from government bodies, health ministries, and systems, to frontline healthcare workers and patients, need to be invested in addressing the local health problems and significantly increase data to define and improve the gaps in care in LMICs. Moreover, interventions can be designed for a more collaborative and effective HIC-LMIC and LMIC-LMIC partnership to increase resources, capacity building, and representation for long-term productivity.

Pulmonary hypertension: From an orphan disease to a global epidemic

[No abstract. Showing first paragraph of article]Pulmonary hypertension is a progressive disease characterized by an elevation of pulmonary artery pressure and pulmonary vascular resistance, leading to right ventricular failure and death. It remains a challenging chronic progressive disease, but the current interest and advent of medical therapy in the last 20 years has significantly changed the perception of medical community in this disease. Pulmonary hypertension is not a specific disease; the majority of cases present with other diseases and various pathological processes that affect the pulmonary vasculature, and consequently increase pulmonary pressure and vascular resistance.