Dysfunction of an ATS valve in the aortic position: the first reported case caused by pannus formation.

A 64-year-old woman underwent aortic valve replacement with a 21-mm Advancing The Standard (ATS) open-pivot mechanical heart valve for bicuspid aortic valve stenosis. In addition to the appearance of a new cardiac murmur, echocardiography performed 3 years after surgery showed a high pressure gradient across the ATS valve and a reduction in the valve orifice area. Cineradiography of the valve revealed restricted leaflet opening. Subsequent multidetector-row computed tomography clearly demonstrated pannus overgrowth on the inflow aspect of the ATS valve. During a repeat operation, subvalvular overgrown pannus was confirmed and the ATS valve was replaced with a bioprosthetic valve. This is the first reported case of prosthetic valve dysfunction resulting from pannus formation in a patient with an ATS valve in the aortic position.