Bicuspid Aortic Valve, from the Unknown till the Perfection of the Species

Abstract

The bicuspid aortic valve (BAV) is the most common congenital cardiac abnormality. Though most often isolated, BAV may be associated with other cardiovascular malformations. BAV-related aortopathy is the most common, sharing genetic alterations and phenotypic heterogeneity characteristics. Sometimes silent for a lifetime, BAV may manifest as aortic valve dysfunction, aortic aneurysm, or more emergent situations, such as endocarditis or aortic dissection. Its embryological origin and the characterization of the genes involved, as well as the histopathological and hemodynamic aspects of its natural history, are becoming increasingly clear. In addition, emerging evidence of rhythm disorders associated with BAV has been identified. A new international nomenclature and classification has been introduced to interpret all the advances made in recent years for the comprehension of this condition. In the guidelines, more attention has been paid to the diagnosis of BAV and related aortopathy, together with surveillance, and family screening. Surgical treatment remains the gold standard, especially in young low-risk patients, and valve repair techniques have been shown to be effective and durable. Finally, the new era of transcatheter techniques is also being applied to dysfunctional BAV, allowing the treatment of patients at high surgical risk, with increasingly promising results, and the possibility of expanding indications through the introduction of more advanced devices. This review aims to comprehensively describe the BAV conundrum, focusing on anatomy, pathophysiology, genetics, diagnosis of BAV-related disorders, and the different treatment options available in the transcatheter era.

Keywords: aortic valve repair; aortopathy; ascending aorta dilatation; bicuspid aortic valve; transcatheter aortic valve replacement (TAVR).

Fig. 1.

Leonardo da Vinci, The aortic valve c. 1512-13, Royal Collection of the United Kingdom (public domain picture).

Fig. 2.

Sievers and Schmidtke classification system. AP, antero-posterior; L, left coronary cusp; Lat, lateral; N, non-coronary cusp; R, right coronary cusp.

Fig. 3.

BAV type, phenotype, and features from the international consensus statement on nomenclature and classification of the congenital BAV. BAV, bicuspid aortic valve; L, left coronary cusp; N, non-coronary cusp; R, right coronary cusp.

Fig. 4.

BAV aortopathy phenotypes. BAV, bicuspid aortic valve.

Fig. 5.

Transesophageal echocardiographic images of bicuspid aortic valve Siervers type 1 right-left or Fused type right-left.

Fig. 6.

Multislice computed tomography images of bicuspid aortic valve Sievers 1 right-left or Fused type right-left. (A) Virtual Basal Ring measurement. (B) Virtual Raphe Ring measurement. (C) Calcium quantification HU 900. (D) Three cusps aorta image. HU, Hounsfield unit; RC, right coronary cusp; NC, non-coronary cusp; LC, left coronary cusp.