Sex differences in bicuspid aortic valve disease

Bicuspid aortic valve (BAV), the most frequent congenital heart disease, is characterized by an uneven distribution between sexes. BAV is three to four times more frequent in men than in women which could be associated with a reduced dosage of X chromosome genes. In addition, BAV has a multifactorial inheritance, low penetrance and variable phenotypes that may lead to different form of valve degeneration and dysfunction over time as well as different incidence of aortic valve and vascular complications between men and women. Definition of the phenotype is the first step in the evaluation of patients with BAV. Among the various phenotypes, BAV with a fusion raphe between the left and the right coronary cusp is the most frequent phenotype observed in men and women. It has been hypothesized that the valve and vascular related complications vary according to the BAV phenotype and this could explain differences in the clinical outcomes of men versus women. However, the evidence on the distribution of the various BAV phenotypes between sexes in not consistent and while some series have described differences between male and female, others have not confirmed those findings. In terms of valvular complications, women present more frequently with aortic stenosis while aortic regurgitation is more frequently diagnosed in men. Furthermore, endocarditis is more frequently reported in men as compared to women. In terms of vascular complications, men show larger diameters of the various parts of the aortic root and ascending aorta and more frequently present complications in terms of aortic aneurysm and dissection as compared to women. Although there are no survival differences between men and women with BAV, compared to the general population some large series have shown that women have worse prognosis. The present review article summarizes the differences between men and women in terms of BAV phenotype, type and incidence of aortic valve and vascular complications that will determine the differences in clinical outcomes.