Eisenmenger syndrome and atrial septal defect: nature or nurture?

'Two-step' percutaneous procedure for repairing the atrial septal defect with severe pulmonary hypertension: a case report

Atrial septal defect is the most common type of congenital heart disease. Interventional closure is currently the best treatment for the atrial septal defect. However, the repair strategy for atrial septal defect accompanies by severe pulmonary hypertension remains controversial. We report a case of an atrial septal defect with severe pulmonary hypertension in which we applied a perforated occlude for atrial septal defect percutaneously at first. After 6 months, when the pulmonary pressure gradually went down, we completely blocked the reserved hole with a closure device percutaneously. We suggest that the stepwise procedure is an important treatment option for select patients with atrial septal defect accompanied by severe pulmonary hypertension.

Atrial septal defect in adulthood: a new paradigm for congenital heart disease

Atrial septal defects (ASDs) represent the most common congenital heart defect diagnosed in adulthood. Although considered a simple defect, challenges in optimal diagnostic and treatment options still exist due to great heterogeneity in terms of anatomy and time-related complications primarily arrhythmias, thromboembolism, right heart failure and, in a subset of patients, pulmonary arterial hypertension (PAH). Atrial septal defects call for tertiary expertise where all options may be considered, namely catheter vs. surgical closure, consideration of pre-closure ablation for patients with atrial tachycardia and suitability for closure or/and targeted therapy for patients with PAH. This review serves to update the clinician on the latest evidence, the nuances of optimal diagnostics, treatment options, and long-term follow-up care for patients with an ASD.

Preventing disease progression in Eisenmenger syndrome

Introduction: Eisenmenger syndrome describes a condition in which a congenital heart defect has caused severe pulmonary vascular disease, resulting in reversed (right-left) or bidirectional shunting and chronic cyanosis.Areas covered: In this paper, the progression of congenital heart defects to Eisenmenger syndrome, including early screening, diagnosis and operability are covered. The mechanisms of disease progression in Eisenmenger syndrome and management strategies to combat this, including the role of pulmonary arterial hypertension therapies, are also discussed.Expert opinion/commentary: Patients with congenital heart disease (CHD) are at increased risk of developing pulmonary arterial hypertension with Eisenmenger syndrome being its extreme manifestation. All CHD patients should be regularly assessed for pulmonary hypertension. Once Eisenmenger syndrome develops, shunt closure should be avoided. The clinical manifestations of Eisenmenger syndrome are driven by the systemic effects of the pulmonary hypertension, congenital defect and long-standing cyanosis. Expert care is essential for avoiding pitfalls and preventing disease progression in this severe chronic condition, which is associated with significant morbidity and mortality. Pulmonary arterial hypertension therapies have been used alongside supportive care to improve the quality of life, exercise tolerance and the outcome of these patients, although the optimal timing for their introduction and escalation remains uncertain.

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

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

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

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

Atrial Septal Defect with Eisenmenger Syndrome: A Rare Presentation

Atrial septal defects (ASDs) are common congenital heart defects (CHD). The clinical course in patients without closure of the ASD is associated with significant morbidity and mortality in advanced age. A small percentage of patients may develop pulmonary arterial hypertension (PAH) due to left to right shunting that impacts morbidity and mortality. Advances in prenatal screening and fetal echocardiography have allowed timely interventions. Nonetheless, some patients still may be diagnosed with ASD in adulthood as an incidental finding or presenting with clinical symptoms such as shortness of breath from right heart failure. We report a case of an adult female presenting with shortness of breath due to ASD causing PAH with Eisenmenger physiology.

Pulmonary Artery Banding in Post-tricuspid Congenital Cardiac Shunting Defects with High Pulmonary Vascular Resistance

Reports of "treat and repair" of cardiac shunting lesions with inoperably high pulmonary vascular resistance (PVR) mostly concern pre-tricuspid defects; post-tricuspid lesions are different. We report our experience with pulmonary artery (PA) banding ± targeted pulmonary hypertension medications in five patients with a large VSD and inoperably high PVR, and review previous reports of PA banding with post-tricuspid defects. Three of our 5 patients had mean PAP > 50 mmHg after banding and no or only a transient fall in PVR. Two patients had mean PAP < 50 mmHg and lower PVR after banding; they had closure of their VSDs but have since had a progressive increase in PVR (follow-up after closure, 3.5 and 7.7 years). Previous reports have also documented difficulty in achieving sufficient band gradient. Of previously reported patients, only one became operable only after banding and targeted therapy, and was repaired; follow-up after repair was short-term (16 months). Our and previous experience demonstrate the difficulty in placing a PA band sufficiently tight to substantially reduce PA pressure. Reported attempts to "treat and repair" post-tricuspid defects are few and have met with limited success, and we found that PVR may increase significantly over time after repair. But more information is needed. Accurate interpretation of experience with "treat and repair" requires: careful characterization of the pulmonary circulation prior to "treating"; considering spontaneously reversible factors at pre-treatment catheterization before ascribing reduction in PVR to medical therapy; and long-term observation of PVR in patients who have had defect closure.

The Role of Non-Coding RNA in Congenital Heart Diseases

Cardiovascular development is a complex developmental process starting with the formation of an early straight heart tube, followed by a rightward looping and the configuration of atrial and ventricular chambers. The subsequent step allows the separation of these cardiac chambers leading to the formation of a four-chambered organ. Impairment in any of these developmental processes invariably leads to cardiac defects. Importantly, our understanding of the developmental defects causing cardiac congenital heart diseases has largely increased over the last decades. The advent of the molecular era allowed to bridge morphogenetic with genetic defects and therefore our current understanding of the transcriptional regulation of cardiac morphogenesis has enormously increased. Moreover, the impact of environmental agents to genetic cascades has been demonstrated as well as of novel genomic mechanisms modulating gene regulation such as post-transcriptional regulatory mechanisms. Among post-transcriptional regulatory mechanisms, non-coding RNAs, including therein microRNAs and lncRNAs, are emerging to play pivotal roles. In this review, we summarize current knowledge on the functional role of non-coding RNAs in distinct congenital heart diseases, with particular emphasis on microRNAs and long non-coding RNAs.

Pulmonary Arterial Hypertension: Iron Matters

The interplay between iron and oxygen is longstanding and central to all aerobic life. Tight regulation of these interactions including homeostatic regulation of iron utilization ensures safe usage of this limited resource. However, when control is lost adverse events can ensue, which are known to contribute to an array of disease processes. Recently, associations between disrupted iron homeostasis and pulmonary artery hypertension (PAH) have been described with the suggestion that there is a contributory link with disease. This review provides a background for iron regulation in humans, describes PAH classifications, and discusses emerging literature, which suggests a role for disrupted iron homeostatic control in various sub-types of PAH, including a role for decompartmentalization of hemoglobin. Finally, the potential for therapeutic options to restore iron homeostatic balance in PAH are discussed.

The Efficacy of a Genetic Analysis of the BMPR2 Gene in a Patient with Severe Pulmonary Arterial Hypertension and an Atrial Septal Defect Treated with Bilateral Lung Transplantation

Severe pulmonary arterial hypertension (PAH) rarely develops in children with an atrial septal defect (ASD), even those with a large defect. We herein report the case of a 27-year-old man with a moderate-sized secundum ASD and right ventricular failure due to severe PAH, which developed in his early teens. He was diagnosed as having a genetic mutation of the bone morphogenetic protein receptor-2 (BMPR2) gene and was successfully treated with bilateral lung transplantation with ASD path closure. In patients with congenital heart disease, a genetic analysis may provide information about the lifetime risk of developing PAH.

Late-Onset Cyanosis and Finger Clubbing in a 37-Year-Old Female with Ebstein's Anomaly and Atrial Septal Defect

It is common to suspect Eisenmenger syndrome when patients with atrial septal defect (ASD) show cyanosis and clubbing. However, ASD accompanying Ebstein's anomaly frequently shows cyanosis without severe pulmonary hypertension, especially in the early period after birth. So the medical decision to decline surgical treatment in those patients should not be determined merely by clinical features such as cyanosis and clubbing. We report a case of a 37-year-old female with Ebstein's anomaly and secundum ASD who showed lip cyanosis and finger clubbing, but maintained normal pulmonary artery pressure and thus underwent successful surgical correction.

KEY WORDS

Atrial septal defect; Cyanosis; Ebstein's anomaly; Eisenmenger syndrome.

Pulmonary hypertension related to congenital heart disease: a call for action

Pulmonary arterial hypertension related to congenital heart disease (PAH-CHD) is a common type of pulmonary arterial hypertension (PAH). Despite this, little emphasis has been given to this group of patients until recently, when compared with idiopathic PAH. This is largely because of the complexity and the wide range of underlying cardiac anatomy and physiology, with a multitude of adaptive mechanisms not fully understood. Pulmonary arterial hypertension related to congenital heart disease is, therefore, best diagnosed and managed in centres specializing in both CHD and PAH, to avoid common pitfalls and old practices and to provide state-of-the-art care. We discuss the optimal management of PAH-CHD patients in a series of actions to be taken in order to optimize short- and long-term outcome, based on current knowledge of the condition and the advent of targeted advanced therapies.

Pulmonary vascular disease related to hemodynamic stress in the pulmonary circulation

Hemodynamic stress in the pulmonary vessel is directly linked to the development of vascular remodeling and dysfunction, ultimately leading to pulmonary hypertension. Recently, some advances have been made in our molecular understanding of the exogenous upstream stimuli that initiate hemodynamic pertubations as well as the downstream vasoactive effectors that control these responses. However, much still remains unknown regarding how these complex signaling pathways connect in order to result in these characteristic pathophysiological changes. This chapter will describe our current understanding of and needed areas of research into the clinical, physiological, and molecular changes associated with pressure/volume overload in the pulmonary circulation.

A novel BMPR2 gene mutation associated with exercise-induced pulmonary hypertension in septal defects

OBJECTIVE

Our study aimed to investigate the relationship between exercise-induced pulmonary arterial hypertension and genetic changes related to the transforming growth factor-β (TGF-β) signalling pathway in patients with cardiac septal defects.

DESIGN

In a population-based group of 44 patients (age 13-25 years) with either isolated ventricular septal defect (n=27) or isolated atrial septal defect (n=17), right ventricular systolic pressure response to submaximal exercise was studied by echocardiography and classified as normal (≤45 mmHg), borderline (45-50 mmHg) or abnormal (>50 mmHg). Three genes related to TGF-β, bone morphogenetic protein receptor type 2 (BMPR2), activin receptor-like kinase 1 (ALK1) and endoglin (ENG), were analyzed by DNA sequencing (only BMPR2) and multiplex ligand-dependent probe amplification (BMPR2, ALK1 and ENG).

RESULTS

Pressure response was borderline in five and abnormal in nine patients. Five patients showed mutations in exon 12 of the bone morphogenetic protein receptor type 2 gene. The previously described polymorphism S775N (c. 2324, G > A) was found in three patients with normal pressure response. The mutation Y589C (c. 1766, A > G), which has not been described previously, was found in two of 14 patients with borderline/abnormal pressure response.

CONCLUSION

Genetic changes in the BMPR2 gene may be overrepresented in patients with cardiac septal defects and exercise-induced pulmonary hypertension.

Human herpesvirus-8 infection of primary pulmonary microvascular endothelial cells

Human herpesvirus-8 (HHV-8) is the causative agent of Kaposi's sarcoma and is associated with the angioproliferative disorders primary effusion lymphoma and multicentric Castleman's disease. Evidence of HHV-8 infection within the pulmonary vasculature of patients with idiopathic pulmonary arterial hypertension (IPAH) has been described. We hypothesize that HHV-8 infection of pulmonary microvascular endothelial cells results in an apoptotic-resistant phenotype characteristic of severe pulmonary arterial hypertension. Our objective was to investigate the ability of HHV-8 to infect human pulmonary microvascular endothelial cells in vitro and characterize the phenotypic effect of this infection. Human pulmonary microvascular endothelial cells were exposed to HHV-8 using two methods (direct virus and co-culture technique). The presence of lytic and latent infection was confirmed. Changes in endothelial cell gene and protein expression and effects on cellular apoptosis were measured. HHV-8 can both lytically and latently infect primary human pulmonary microvascular endothelial cells in vitro. HHV-8 infection results in significant changes in gene expression, including alterations of pathways important to cellular apoptosis. HHV-8 infection also alters expression of genes integral to the bone morphogenic protein pathway, including down-regulation of bone morphogenic protein-4. Other genes previously implicated in the development of PAH are affected by HHV-8 infection, and cells infected with HHV-8 are resistant to apoptosis.

Pathogenic mechanisms of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a complex disease that causes significant morbidity and mortality and is clinically characterized by an increase in pulmonary vascular resistance. The histopathology is marked by vascular proliferation/fibrosis, remodeling, and vessel obstruction. Development of PAH involves the complex interaction of multiple vascular effectors at all anatomic levels of the arterial wall. Subsequent vasoconstriction, thrombosis, and inflammation ensue, leading to vessel wall remodeling and cellular hyperproliferation as the hallmarks of severe disease. These processes are influenced by genetic predisposition as well as diverse endogenous and exogenous stimuli. Recent studies have provided a glimpse at certain molecular pathways that contribute to pathogenesis; these have led to the identification of attractive targets for therapeutic intervention. We will review our current understanding of the mechanistic underpinnings of the genetic and exogenous/acquired triggers of PAH. The resulting imbalance of vascular effectors provoking pathogenic vascular changes will also be discussed, with an emphasis on common and overarching regulatory pathways that may relate to the primary triggers of disease. The current conceptual framework should allow for future studies to refine our understanding of the molecular pathogenesis of PAH and improve the therapeutic regimen for this disease.