The Natural History of Bicuspid Aortic Valve Disease

The bicuspid aortic valve (BAV) is the most common congenital heart defect with an estimated prevalence of between 0.5% and 2% in the United States, representing up to 6.5 million individuals. Most individuals with BAV will develop valvular and/or aortic complications related to their BAV. How these various complications relate to one another and why they arise remain elusive. Yet, astute observations have yielded relevant classification systems that leverage valvular morphology, aortic shape, and genetic alteration patterns. Emerging evidence supports the existence of BAV phenotypes that may have different patterns of disease presentation, rates of progression, and risk of secondary complications. We review the natural history of BAV in light of known clas-sification systems to illustrate a framework through which future hemodynamic, cell biologic, and other studies can better correlate with clinical endpoints. Consistent utilization of valvular, aortic, and genetic classification systems in the management and study of BAV may facilitate insight into the patterns of the disease, with prog-nostic and therapeutic significance for individuals who experience this common structural heart disease.