Bicuspid Aortic Valve in Children and Young Adults for Cardiologists and Cardiac Surgeons: State-of-the-Art of Literature Review

Abstract

Bicuspid aortic valve disease is the most prevalent congenital heart disease, affecting up to 2% of the general population. The presentation of symptoms may vary based on the patient's anatomy of fusion, with transthoracic echocardiography being the primary diagnostic tool. Bicuspid aortic valves may also appear with concomitant aortopathy, featuring fundamental structural changes which can lead to valve dysfunction and/or aortic dilatation over time. This article seeks to give a comprehensive overview of the presentation, treatment possibilities and long-term effects of this condition. The databases MEDLINE, Embase, and the Cochrane Library were searched using the terms "endocarditis" or "bicuspid aortic valve" in combination with "epidemiology", "pathogenesis", "manifestations", "imaging", "treatment", or "surgery" to retrieve relevant articles. We have identified two types of bicuspid aortic valve disease: aortic stenosis and aortic regurgitation. Valve replacement or repair is often necessary. Patients need to be informed about the benefits and drawbacks of different valve substitutes, particularly with regard to life-long anticoagulation and female patients of childbearing age. Depending on the expertise of the surgeon and institution, the Ross procedure may be a viable alternative. Management of these patients should take into account the likelihood of somatic growth, risk of re-intervention, and anticoagulation risks that are specific to the patient, alongside the expertise of the surgeon or centre. Further research is required on the secondary prevention of patients with bicuspid aortic valve (BAV), such as lifestyle advice and antibiotics to prevent infections, as the guidelines are unclear and lack strong evidence.

Keywords: aortopathy; bicuspid aortic valve; classification; diagnosis; treatment.

Scheme 1

A clinical algorithm for the management of BAV based on TTE is presented herewith. COR; Recommendations for useful, effective, and beneficial indications; LOE; The level of evidence is based on moderate quality evidence from one or more well-designed, executed non-randomised studies, observational or registry studies, or meta-analyses; randomized and non-randomized observational or registry studies, meta-analyses, and physiological or mechanistic studies in humans. Abbreviations; BAV, Bicuspid Aortic Valve; ACC/AHA; American College of Cardiology/American Heart Association; COR; class of recommendation; ESC/ESCTS; European Society of Cardiology/European Society of Cardiothoracic Surgery; LOE, level of evidence.

Figure 1

Fused bicuspid aortic valve. Panel (A) represents a short-axis normal tricuspid aortic pattern with anatomical proximities. Panel (B–D) represent three cusps fusion patterns seen in the short heart axis. All BAVs have three sinuses. Raphe structure is between the fused cusps. Non fused cusp is prominent in respect to the fused ones. (B) left-noncoronary fusion pattern; (C) Right-noncoronary fusion pattern; (D) right-left fusion pattern. The commissure angle of the non fused cusp has a degree < 180°. L, left coronary sinus; LA, left atrium; LC, left cusp; LCA, left coronary artery; MV, mitral valve; N, non-coronary sinus; NC, non-coronary cusp; PA, pulmonary artery; R, right coronary sinus; RC, right cusp; RCA, right coronary artery; RV, right ventricle. Licenses Centre Cardiologique du Nord (with permission). License Number 5644110549132 License date 8 October 2023; publication NEJM; Title: Mitral valve Repair for Mitral valve prolapse.

Figure 2

Aorta with normal morphostructure (panel (A,B) is reported. Panel (A): structural support and elasticity are conferred to the aorta through a morphostructure characterized by alternating layers of elastic lamellae and smooth muscle cells. Histologically, the smooth muscle cells of the aorta in individuals with tricuspid valves are attached to the adjacent elastin-collagen matrix by fibrillin 1 microfibrils. Panel (B): morphostructure of the aorta with bicuspid valves that may be deficient in fibrillin 1. This deficiency reaches a finale toward a disrupted morpho-architecture whereby smooth muscle cells detach, accompanied by a tide in local levels of matrix metalloproteinases (MMPs), leading to loss of integrity in the extracellular matrix and the accumulation of apoptotic cells. These events may drive to an aorta with impair structural integrity, decreased elasticity and marked tendency towards structural weakening. Licenses Centre Cardiologique du Nord (with permission); order number License Number 5663550412220; License date 7 November 2023; publication NEJM; Title: Aortic Dilatation in Patients with Bicuspid Aortic Valve.

Figure 3

Clinical presentation and phenotypes of the BAV in patients during somatic growth and in the young adults. Various presenting phenotypes in children, adolescents, and young adults with bicuspid aortic valve are depicted in the illustrative table. The yellow box indicates the evolution of BAV in the population without AV dysfunction. The brown box illustrates the type of AV disorder while the grey box and the blue box respectively highlight the aortopathy and the disorders (genetic and congenital) that can be associated with the BAV. The red arrow indicates those patients who have aortic valve stenosis or regurgitation that manifests symptomatically during somatic growth or as young adults. AV, aortic valve; AVS, aortic valve stenosis; AVR, aortic valve regurgitation; BAV, bicuspid aortic valve; CHD, congenital heart disease; SAVS, supra-aortic valve stenosis VSD, ventricular septal defects.

Figure 4

The illustration shows the recommended imaging intervals for the aorta in patients with BAV. The color of the box corresponds to the AHA/ACC guidelines for diagnostic testing (purpure, green and blue) and intervention (rose). From Nappi et al. [3,13,16,17,18,23,24].

Figure 5

The figure discloses patterns of bicuspid aortopathy with the peculiar biologic features of the normal aorta (A) and the three types of bicuspid aortopathy (B–D). The three morphological types illustrated provide a crucial contribution to the best optimal surgical treatment to be performed for bicuspid aortopathy. Licenses Centre Cardiologique du Nord (with permission); order number License Number 5644101266756; License date 8 October 2023; publication NEJM; Title: Aortic Dilatation in Patients with Bicuspid Aortic Valve.

Figure 6

The bicuspid valve anomaly is indicated. BAV may manifest with other patho-anatomical anomalies including a morphostructural disorder of the medial tunica of the proximal ascending aorta resulting in dilatation of the ascending aorta and medial tunica of the proximal pulmonary artery. In some cases, there are changes in the coronary anatomy. The fusion configuration of the aortic valve cusps promotes changes in aortic wall shear stress and the resulting flow pattern. In the open BAV condition in the phenotype characterized by a right-left fusion, the jet is directed towards the right anterior wall of the ascending aorta. This distribution of flow travels in a right-handed helical direction causing dilation predominantly of the ascending aorta. In the fusion phenotype of the right and non-coronary cusps the jet is directed towards the posterior wall of the aorta, therefore from a biomechanical point of view the shear stress produced at the level of the can lead to aortic dilatation within the proximal arch. Licenses Centre Cardiologique du Nord (with permission); order number License Number 5655230377022; License date 8 October 2023; publication NEJM; Title: Aortic Dilatation in Patients with Bicuspid Aortic Valve.

Figure 7

The Ross procedure is shown in Figures (A,B) with the two PA harvesting methods. (A): Subcoronary technique. (B): Full root replacement technique. Whichever technique is selected, the PA should be inserted within the annulus of the native aortic root. In Figure (C) technical modifications of the Ross procedure directed at mitigating late PA dilatation and failure are reported. (Right): autologous inclusion technique. (Center): dacron inclusion technique. (Left): extra-aortic annuloplasty and interposition graft. PA, pulmonary autograft. Adapted from Mazine A et al. [124,137].

Figure 8

Left: The Ross procedure may be performed using subcoronary (A) or miniroot (B). Advantages and pitfalls of the Ross procedure are reported. Right: Indications and contraindications for the Ross procedure in children, adolescent and young adult patients are depicted. Patients should be referred to a high-volume referral center and referred to an experienced surgeon. This proposed algorithm requires to be further validated and supported by practice guidelines.

Figure 9

Illustrates the decision-making algorithm employed by the medical team in the management of bicuspid aortopathy. Abbreviations; AVR, aortic valve replacement; CT, computed tomography; MRI, magnetic resonance imaging. Adapted from Nappi et al. [3,53,90,160,162,197,198,199,200,201,202,203,204,205,206,207,208].