[The mitral apparatus and surgery of sub-valvular aortic stenosis].

The authors present three eases of subvalvular aortic stenosis caused by an abnormality of the mitral valve mechanism which required placement of a prosthetic valve. They describe the types of mitral valve abnormality which are reported in the literature to have caused obstruction to the aortic outflow tract. They analyse the criteria for diagnosis of this condition, and the surgical treatment. The placement of a prosthetic mitral valve does not always remove the obstruction to the aortic outflow, especially if there is an abnormality in the position of the mitral ring.