Prosthetic Ring Endocarditis with Shrunken Mitral Annulus Late After Undersized Mitral Annuloplasty

We report a case of supra-annular mitral valve replacement for a patient with prosthetic ring endocarditis that developed late after undergoing undersized mitral annuloplasty (UMAP). A 58year-old man had undergone left ventriculoplasty and UMAP with a 26-mm semi-rigid full ring for dilated cardiomyopathy and functional mitral regurgitation. The mitral valve had progressively stenosed and he developed prosthetic ring endocarditis 5 years after the operation. In the surgery, there were brownish fresh vegetations around the anterior mitral leaflet and the prosthetic ring. The mitral annulus was very small, even after removal of the infected ring prosthesis and debridement of the infected tissues. We implanted a 22-mm mechanical prosthesis in the supra-annular position using everting mattress sutures to prevent the valve leaflets from getting stuck by the thickened subannular tissue. Herein, we discuss the surgical procedures for a shrunken mitral annulus.