Clinical and Pathophysiological Implications of a Bicuspid Aortic Valve

Abstract

You are contacted by a concerned 34-year-old airline pilot with a leaky bicuspid aortic valve recently diagnosed by an echocardiogram that had been requested by his new employer as part of a routine medical assessment. He claims that he is perfectly healthy but is at risk of losing his job over his condition. He is concerned that his disease is hereditary and that his children may also be at risk. The patient, his attorney, and his insurance company have requested a statement from you as to the cause, possible complications, and treatment options associated with a congenital malformation of the aortic valve. The bicuspid aortic valve (BAV) is the most common congenital cardiac malformation, occurring in 1% to 2% of the population. The majority of BAV patients develop complications requiring treatment. Physicians are often challenged when asked to provide evidence-based advice about BAV disease because the pathogenesis and pathophysiology of this disease are not well understood. BAVs are the result of abnormal aortic cusp formation during valvulogenesis. Adjacent cusps fuse to form a single aberrant cusp, larger than its counterpart yet smaller than 2 normal cusps combined. BAVs are likely the result of a complex developmental process, not simply the fusion of 2 normal cusps. In fact, congenital aortic valve malformations may reflect a phenotypic continuum of unicuspid valves (severe form), bicuspid valves (moderate form), tricuspid valves (normal), and the rare quadricuspid forms1 (Figure 1). Figure 1. A, Normal tricuspid aortic valve. The cusps (arrowheads) and the 3 commissures (arrows) are clearly seen. Three sinuses of Valsalva are also seen. The cusps coapt normally to give a functionally normal valve. B, Congenitally bicuspid aortic valve, with one cusp larger (asterisk) than the other. The cusps show thickening due to fibrosis. Two commissures (arrows) are seen. One raphe (arrowhead) is …