Aortic valve regurgitation (AR) is due to leaflet disease and/or dilatation of the functional aortic annulus complex. Understanding the precise 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.

From our institutional echocardiography database, we identified all patients with native moderate-to-severe (3+) or severe (4+) AR who presented between 2014–2019. Patients with infective endocarditis, aortic dissection, at least moderate aortic stenosis or 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, and Ic=aortic annular dilation), Type II – leaflet prolapse, and Type III – leaflet restriction. Valve anatomy was determined and clinical outcomes including death, and surgical intervention were also extracted.

A total of 560 patients with moderate-to-severe (3+) or severe (4+) AR were identified, 270 were excluded (92 patients for endocarditis, 152 patients for concomitant valve disease, 23 patients for acute aortic dissection, and 11 patients for other reasons), thus 282 patients (77.3% male) constituted the study population. The most common mechanism was Type II (leaflet prolapse) identified in 98 (35%) patients, followed by Type Ia (ascending aorta dilation) in 78 (28%) patients. In 164 (58%) patients, multiple mechanisms of AR were identified. 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±2.4years. Of the 158 (57%) patients who underwent surgical intervention, aortic valve repair was performed in 77 patients (49%) and aortic valve replacement was performed in 80 (51%) patients.

In a large cohort of patients with at least moderate-to-severe (3+) isolated pure native AR, Type II (leaflet prolapse) was the most commonly seen mechanism. Multiple mechanisms are present in most AR patients, including those with BAV. Understanding the mechanisms of isolated AR may facilitate aortic valve repair and avoid the need for valve replacement.