Acute severe aortic insufficiency during cardiopulmonary bypass in a bicuspid aortic valve with unrecognized annular displacement and fibrous strands: a case report.

BACKGROUND: Bicuspid aortic valve (BAV) with displacement of the attachment of the conjoined aortic leaflet and fibrous strands is a rare cardiac malformation. We report a case of BAV that presented as acute massive aortic regurgitation during cardiopulmonary bypass for a planned non-valve-related procedure and was successfully treated by emergency aortic valve replacement.

CASE SUMMARY: A 70-year-old man with triple vessel coronary disease and severe left ventricular systolic dysfunction underwent coronary bypass grafting and graft replacement of the ascending aorta. Acute aortic regurgitation occurred during ventricular fibrillation and after de-clamping of the aortic graft. Intra-operative findings included a fused BAV (right-left cusp fusion), very asymmetrical leaflet (commissure angle of the non-fused leaflet 135°), three aortic sinuses, and conjoined leaflets originating from the myocardium in the inter-ventricular septum. The aortic leaflets were resected and replaced with a prosthetic aortic valve at the attachment site of the conjoined leaflets. Post-operatively, no peri-valvular leaks were observed, and left ventricular function was improved.

DISCUSSION: Intra-operative acute massive aortic regurgitation may be caused by a morphologically abnormal aortic leaflet and root complex in patients with a BAV. The dilated aortic root, asymmetrical leaflet, and abnormal aortic leaflet insertion, with thick septal myocardium of the coronary aortic sinus, might have caused unstable leaflet co-aptation, leading to deformation of the aortic leaflets influenced by the change in myocardial tone and intra-operative change in the sinotubular junction. Familiarity with the classification of congenital BAV, and the anatomy of the normal and abnormal aortic root complex, is important.