[Mitral valve insufficiency due to ballooning. A surgical series of 70 cases]

The authors report 70 cases of mitral regurgitation due to ballooning. For the surgeon this is the most frequent cause of degenerative mitral regurgitation in patients around 60-years-old. The aetiology still remains unknown. There are two opposing theories--the congenital and the acquired. The appearances at operation are characteristic--a localised or diffuse ballooning of one or both cusps with elongation of the chordae attached to the ballooned portion. Two histological features are noted--myxomatous degeneration of the cusp and the absence of any inflammatory process. Ballooning may be asymptomatic and bening for a long time before evolving progressively or suddenly into important mitral regurgitation. The pre-operative diagnosis is aided by left ventricular angiography and echocardiography. Surgical treatment, guided by the findings at operation, usually involves mitral valve replacement or, less frequently, mitral valve repair.