Pathogenesis of paravalvular leakage as a complication occurring in the late phase after surgery.

Paravalvular leakage (PVL) remains an unavoidable late complication after valve surgery. We indicate surgery only cases with progressive congestive heart failure and/or hemolytic anemia. We review our clinical experiences of PVL surgery. Between 1992 and 2009 we experienced 8 cases of aortic PVL-6 subjects after primary aortic valve replacement (AVR) and 2 subjects after re-AVR-and 10 subjects with mitral PVL-5 cases after primary mitral valve replacement (MVR) and 5 cases after re-MVR. Mitral PVL began in the later phases after surgery and had more severe symptoms, because of heart failure and/or hemolytic anemia, than aortic PVL. Aortic PVL occurred more frequently because of laxation of sutured threads without frequent sites. Conversely, mitral PVL was mainly caused by cutting annulus tissue around the anterior commisurae after primary MVR, and by a valve-on-valve structure on the middle scallop of the posterior leaflet or circumferentially after re-MVR. All operations were performed safely and all patients were discharged uneventfully. No cases experienced recurrence of PVL in the follow-up period. The symptoms of PVL became exacerbated, and our surgical indications based on these symptoms were validated. Valve-on-valve replacement, which was a major cause of PVL after re-MVR, should be avoided in a re-MVR procedure. Cautious follow-up is necessary, even in the late phase after surgery, especially for patients who have undergone MVR.