DIVERTICULA OF ANTERIOR MITRAL-VALVE LEAFLET AS A CAUSE OF SUBVALVULAR AORTIC-STENOSIS

A 77-year-old male patient presented with symptoms of shortness of bre ath, fatigue, chest pain on exertion and dizziness. Transthoracic echo cardiography suggested the presence of a diaphragmatic type of obstruc tion in the subaortic area of the left ventricular outflow tract. The systolic peak gradient at rest was 34 mmHg with a mean of 23 mmHg. Car diac catheterization demonstrated rounded radioliucencies in the left ventricular outflow tract in the form of two ''pouches'' that moved ba ck and forth causing subaortic stenosis. There was also a 70% stenosis of the left anterior descending coronary artery. Left ventricular fun ction was normal. At surgery, a transesophageal echocardiogram demonst rated two distinct pouches arising from the anterior leaflet of the mi tral valve. The larger of the two originated near the free edge of the leaflet and was attached via a chord to the membranous septum travers ing the subaortic area of the left ventricular outflow tract. The pati ent underwent a left internal mammary to left anterior descending bypa ss graft, excision of the larger pouch and over-sewing of the smaller pouch. The excision and repair were performed through the aortic root and aortic valve. The patient made an uncomplicated recovery and on fo llow up his symptoms disappeared. This case shows the excellent result s that can be obtained by surgery of diverticula of the mitral valve c ausing intermittent subaortic stenosis, a rare pathologic entity, morp hologically different from the classical diaphragmatic subaortic steno sis.