Abstract 14451: Mechanistic Classification and Outcomes of Isolated Aortic Regurgitation in a Contemporary Cohort of Patients

Introduction: Aortic valve regurgitation (AR) is due to leaflet disease and/or dilatation of the functional aortic annulus complex. Understanding the mechanism(s) of AR informs surgical planning of valve and aorta repair. In this study we aimed to examine the etiologies, mechanisms, and outcomes of isolated pure native severe AR in a contemporary consecutive cohort of patients. Methods: From our institutional echocardiography database, we identified all patients with native moderate-to-severe (3+) or severe (4+) AR between 2014-2019. Patients with infective endocarditis, aortic dissection, or other concomitant valve disease were excluded. AR was classified using the El-Khoury classification: Type I-normal leaflet motion (Ia = ascending aorta and sinotubular junction dilatation, Ib = aortic root dilation, Ic = aortic annular dilation), Type II-leaflet prolapse, and Type III-leaflet restriction. Valve anatomy and clinical outcomes were also extracted. Results: A total of 560 patients with at least moderate-to-severe (3+) AR were identified, 270 were excluded (92 patients for endocarditis, 152 patients for concomitant valvulopathy, 23 patients for acute aortic dissection, and 11 patients for other reasons), and 282 patients (77.3% male) were included. The most common mechanism was Type II (leaflet prolapse), idenfied in 98 (35%) patients. Multiple mechanisms of AR were identified in 164 (58%) patients. The most common combination was Type Ib (aortic root dilation) and Type II (leaflet prolapse) seen in 45 (27%) patients. Ninety-nine (35%) patients had a bicuspid aortic valve (BAV). Follow-up was available for 275 patients (98%) with a median duration of 4.7±2.4 years. Of the 158 (57%) patients who underwent surgical intervention, valve repair was performed in 77 patients (49%) and valve replacement in 80 (51%) patients. Valve intervention was more common in women (70%) than in men (54%). Conclusion: In a large contemporary cohort of patients with at least moderate to severe (3+) isolated pure native AR, Type II (leaflet prolapse) was the most common mechanism, however multiple mechanisms are present in most AR patients. Aortic valve repair now accounts for almost half of the surgical interventions for isolated AR in our center.