Abstract
A 61-year-old man presented 9 months after bioprosthetic mitral valve implantation with progressive exertional dyspnea. Transesophageal echocardiography revealed severe mitral stenosis with diffuse leaflet thickening but no calcification. Subsequent pathologic examination of the valve demonstrated infiltrating fibroconnective tissue and chronic inflammation. Careful echocardiographic follow-up of this valve type may be warranted, especially in patients with early recurrent symptoms.