Advances in Transcatheter Aortic Valve Therapy in Bicuspid Aortic Valve Disease: Insight into Patient Selection, Management, and Future Directions

Bicuspid aortic valve (BAV) disease is the most common congenital abnormality and is characterized by a risk of premature aortic valve disease, predominantly aortic stenosis. Surgery remains the treatment of choice for patients with symptomatic BAV disease, but, in patients who are unsuitable for surgical aortic valve replacement, transcatheter aortic valve replacement (TAVR) is currently used as an alternative to surgery, although there is no official recommendation for their management, since BAV patients with severe aortic stenosis have been excluded from the major TAVR randomized clinical trials. Patients with BAV stenosis present anatomic challenges for treatment with TAVR. The BAV annulus often has an elliptical shape and is larger than the tricuspid valve, and is more likely to exhibit severe eccentric calcification. In addition, BAV is often associated with a dilated, horizontal ascending aorta, and effaced sinuses. The calcified raphe may also place differential stress on the expansion of the transcatheter valve, increasing the risk of suboptimal positioning and consequently the risk of paravalvular leakage, new pacemaker implantation, new-onset left bundle branch block, and annular rupture. Moreover, coronary obstruction may occur when leaflet fusion results in a longer leaflet. Although some of these challenges have been successfully overcome using new-generation devices, the complication rate is still relatively high and requires a deeper understanding of the patient's specific complex and variable anatomy. Selection of the type and size of the transcatheter valve according to the patient's individual anatomy is critical to achieving successful results. Therefore, given the increasing frequency of BAV stenosis in younger patients, and the worldwide expansion in the application of TAVR in younger and lower surgical-risk patients, preprocedural multimodality imaging involving CT scan and three-dimensional echocardiography is mandatory to understand the complex and variable anatomy of BAV disease and improve both procedural results and short- and long-term outcomes in these patients.