RESUMO
An 81-year-old man underwent aortic valve replacement with a 21-mm Medtronic Mosaic porcine bioprosthesis for the treatment of bicuspid aortic valve stenosis. In addition to the appearance of chest discomfort on effort and a new diastolic murmur, echocardiography performed 2 years and 3 months after the surgery showed a high pressure gradient across the bioprosthetic valve and a reduction in the valve orifice area. Prosthetic valve dysfunction was diagnosed. During a repeat operation, 2 large tears on the left cusp and a subvalvular overgrown abundant pannus were observed, and the bioprosthetic valve was replaced with a 19-mm On-X mechanical heart valve. On analysis of the explant bioprosthesis, the right non-coronary stent post was bent outwards by approximately 9°, it compressed the left cusp by pulling the left right and left non-coronary stent posts closer together, thus altering the leaflet geometry and function. We speculated that pannus formation had resulted from turbulent blood flow caused by impaired or altered leaflet function. The 2 large tears appeared to be the result of contact with the bias cloth secondary to the stent distortion.