Bicuspid Aortic Valvulopathy and Associated Aortopathy: a Review of Contemporary Studies Relevant to Clinical Decision-Making

Michael H. Kwon, Thoralf M. Sundt

The bicuspid aortic valve (BAV) phenotype is becoming increasingly recognized as a complex and heterogeneous clinical entity, with some but not all patients developing accelerated degrees of both aortic insufficiency (AI) and aortic stenosis (AS) in comparison to patients with tricuspid aortic valves (TAV). In addition, there remains a well-established association between the BAV phenotype and aortic enlargement independent of valve function as well as progression among some to ascending aortic aneurysm and the attendant concern over risk of aortic dissection. Because the understanding of the complexity of the BAV phenotype is evolving as quickly as are the options for medical, surgical, and interventional therapy, this review aims to provide an update on the most clinically relevant recent advances in the realm of BAV and associated aortopathy from a genetic, morphologic, and clinical outcomes perspective in order to give the practicing clinician a deeper understanding of how to approach both medical and surgical decision-making in the patient with BAV. The following major principles have emerged in recent years including (1) the importance of cusp anatomy and its implications on the long-term risk of AI, aortic dilation, and aortic dissection, (2) the role of post-valvular flow dynamics in the pathogenesis of aortic dilation in BAV patients, (3) the ability of aortic valve replacement to halt accelerated dilation rates, and (4) the finding that the risk of aortic dissection, while still overall intermediate is much more akin to the baseline risk present in TAV patients rather than the much higher rates observed in patients with Marfan's disease. Together, these data support the less aggressive approach to aortic replacement in BAV patients as reflected in the most recent ACC/AHA guidelines and provide a stronger basis upon which future studies, including those aimed at medical and transcatheter therapies, stand to make further impact on our ability to optimally treat this epidemiologically important and complex population of patients.