Bicuspid pulmonic valve

Valvular heart disease in congenital heart disease: a narrative review

Patients with congenital heart disease (CHD) are one of the fastest growing populations in cardiology, and valvular pathology is at the center of many congenital lesions. Derangements in valvular embryology lead to several anomalies prone to dysfunction, each with hemodynamic effects that require appropriate surveillance and management. Surgical innovation has provided new treatments that have improved survival in this population, though has also contributed to esotericism in patients who already have unique anatomic and physiologic considerations. Conduit and prosthesis durability are often monitored collaboratively with general and specialized congenital-focused cardiologists. As such, general cardiologists must become familiar with valvular disease with CHD for appropriate care and referral practices. In this review, we summarize the embryology of the semilunar and atrioventricular (AV) valves as a foundation for understanding the origins of valvular CHD and describe the mechanisms that account for heterogeneity in disease. We then highlight the categories of pathology from the simple (e.g., bicuspid aortic valve, isolated pulmonic stenosis) to the more complex (e.g., Ebstein's anomaly, AV valvular disease in single ventricle circulations) with details on natural history, diagnosis, and contemporary therapeutic approaches. Care for CHD patients requires collaborative effort between providers, both CHD-specialized and not, to achieve optimal patient outcomes.

Pulmonary Artery Aneurysm Associated with Bicuspid Pulmonary Valve

A 73-year-old Japanese man was admitted with an asymptomatic pulmonary artery aneurysm. However, chest X-ray and contrast-enhanced thoracic computed tomography revealed a protrusion at the second left branch that in fact was a pulmonary artery aneurysm with a diameter of 50 mm. Transesophageal echocardiography showed a bicuspid pulmonary valve, and cardiac catheterization revealed pulmonary stenosis with a pressure gradient of 45 mmHg, but no other heart diseases were noted. An extremely rare pulmonary artery aneurysm associated with an isolated bicuspid pulmonary valve was diagnosed.

A case of isolated bicuspid pulmonary valve

We present a 73 years old woman who presented with pelvic cancer, ongoing sepsis and presumably a new diastolic murmur. Her transthoracic echocardiogram, as part of a sepsis screen, showed an abnormal pulmonary valve with moderate regurgitation. Trans-oesophageal echocardiography using 3D imaging showed a bicuspid pulmonary valve as the cause for the moderate regurgitation, but with no clear source of infection. Bicuspid pulmonary valve as an isolated clinical entity is a rare finding in clinical practice. Bicuspid pulmonary valves tend to be more commonly associated with other congenital cardiac anomalies. Whereas, the incidence of bicuspid aortic valve is estimated to be about 1-2%, the incidence of bicuspid pulmonary valve is thought to be much lower at around 0.1%. This could be an underestimate due to difficulty in visualising the pulmonary valve en-face on standard two-dimensional echocardiography. The true prevalence of the condition may be uncovered by the routine use of 3D echocardiography.

Pulmonic Valve Disease: Review of Pathology and Current Treatment Options

PURPOSE OF REVIEW

Our review is intended to provide readers with an overview of disease processes involving the pulmonic valve, highlighting recent outcome studies and guideline-based recommendations; with focus on the two most common interventions for treating pulmonic valve disease, balloon pulmonary valvuloplasty and pulmonic valve replacement.

RECENT FINDINGS

The main long-term sequelae of balloon pulmonary valvuloplasty, the gold standard treatment for pulmonic stenosis, remain pulmonic regurgitation and valvular restenosis. The balloon:annulus ratio is a major contributor to both, with high ratios resulting in greater degrees of regurgitation, and small ratios increasing risk for restenosis. Recent studies suggest that a ratio of approximately 1.2 may provide the most optimal results. Pulmonic valve replacement is currently the procedure of choice for patients with severe pulmonic regurgitation and hemodynamic sequelae or symptoms, yet it remains uncertain how it impacts long-term survival. Transcatheter pulmonic valve replacement is a rapidly evolving field and recent outcome studies suggest short and mid-term results at least equivalent to surgery. The Melody valve® was FDA approved for failing pulmonary surgical conduits in 2010 and for failing bioprosthetic surgical pulmonic valves in 2017 and has been extensively studied, whereas the Sapien XT valve®, offering larger diameters, was approved for failing pulmonary conduits in 2016 and has been less extensively studied. Patients with pulmonic valve disease deserve lifelong surveillance for complications. Transcatheter pulmonic valve replacement is a novel and attractive therapeutic option, but is currently only FDA approved for patients with failing pulmonary conduits or dysfunctional surgical bioprosthetic valves. New advances will undoubtedly increase the utilization of this rapidly expanding technology.

Abnormal Haemodynamic Flow Patterns in Bicuspid Pulmonary Valve Disease

Abnormal flow patterns in the aortas of those with bicuspid aortic valves (BAVs) are increasingly recognized as important in the pathogenesis of aortic dilatation but pulmonary flow patterns in bicuspid pulmonary valves have not been studied. Bicuspid pulmonary valve disease is rare and a small numbers of case reports describe concomitant pulmonary artery dilation similar to the dilation of the ascending aorta, which is often seen in BAVs disease. We examined three cases of bicuspid pulmonary valve disease, 10 healthy volunteers and 10 patients with BAV disease but a tricuspid pulmonary valve. All participants underwent anatomical and functional imaging of the pulmonary valve, pulmonary artery, and right ventricle as well as advanced time-resolved 3-dimensional cardiac magnetic resonance imaging (4D flow) to assess the flow pattern in the pulmonary artery. All patients with a bicuspid pulmonary valve had pulmonary artery dilation and showed distinct helical flow abnormalities with increased rotational flow and increased flow displacement compared to a mild left-handed flow pattern in the healthy volunteers. Additionally, there was marked asymmetry seen in the systolic wall shear stress (WSS) pattern, with the highest values in the anterior wall of the pulmonary artery. In comparison, patients with a BAV but a tricuspid pulmonary valve had normal flow patterns in the pulmonary artery. These haemodynamic findings are similar to recent studies in bicuspid aortic disease, and suggest the importance of flow patterns in the pathophysiology of vessel dilation in both aortic and pulmonary bicuspid valve disease.

Echocardiographic two-dimensional view of the pulmonary valve in infants: the high transsternal view

Neonates and small infants have unique characteristics that make it possible to obtain echocardiographic views that are inaccessible in older patients. A high transsternal approach through the cartilaginous sternum and the thymus gland allows visualisation of a short-axis view of the pulmonary valve. This view should be included as part of routine protocols for echocardiographic examinations performed in this age group.

CT and MRI of pulmonary valvular abnormalities

Pulmonary valve disease constitutes a wide spectrum of conditions. Traditionally, echocardiography has been the technique of choice for the evaluation of pulmonary and other valvular disease. However, with advances in technology, computed tomography (CT) and magnetic resonance imaging (MRI) are playing increasingly important roles in the evaluation of these disorders. In this article, we review the normal appearance of the pulmonary valve and then illustrate various variants and pathological entities of the pulmonary valve.

4D-cine CT imaging of a bicuspid pulmonary valve

A 71-year-old woman underwent diagnostic workup for progressive shortness of breath. Transthoracic echocardiography showed a dilated main pulmonary artery (MPA) and an anomalous configuration of the pulmonary valve. CT revealed a bicuspid pulmonary valve (BPV) and confirmed MPA dilation. Further congenital abnormalities were excluded. An isolated finding of BPV is rather rare. To our knowledge we present the first 4-dimensional CT images of a BPV. As in this case, 4-dimensional cine cardiac CT may be helpful to reveal the underlying cause of MPA dilation.

Insufficient versican cleavage and Smad2 phosphorylation results in bicuspid aortic and pulmonary valves

Bicuspid or bifoliate aortic valve (BAV) results in two rather than three cusps and occurs in 1-2% of the population placing them at higher risk of developing progressive aortic valve disease. Only NOTCH-1 has been linked to human BAV, and genetically modified mouse models of BAV are limited by low penetrance and additional malformations. Here we report that in the Adamts5(-/-) valves, collagen I, collagen III, and elastin were disrupted in the malformed hinge region that anchors the mature semilunar cusps and where the ADAMTS5 proteoglycan substrate versican, accumulates. ADAMTS5 deficient prevalvular mesenchyme also exhibited a reduction of α-smooth muscle actin and filamin A suggesting versican cleavage may be involved in TGFβ signaling. Subsequent evaluation showed a significant decrease of pSmad2 in regions of prevalvular mesenchyme in Adamts5(-/-) valves. To test the hypothesis that ADAMTS5 versican cleavage is required, in part, to elicit Smad2 phosphorylation we further reduced Smad2 in Adamts5(-/-) mice through intergenetic cross. The Adamts5(-/-);Smad2(+/-) mice had highly penetrant BAV and bicuspid pulmonary valve (BPV) malformations as well as increased cusp and hinge size compared to the Adamts5(-/-) and control littermates. These studies demonstrate that semilunar cusp malformations (BAV and BPV) can arise from a failure to remodel the proteoglycan-rich provisional ECM. Specifically, faulty versican clearance due to ADAMTS5 deficiency blocks the initiation of pSmad2 signaling, which is required for excavation of endocardial cushions during aortic and pulmonary valve development. Further studies using the Adamts5(-/-); Smad2(+/-) mice with highly penetrant and isolated BAV, may lead to new pharmacological treatments for valve disease.