Subaortic stenosis secondary to pannus from a mechanical mitral valve

A variety of conditions can lead to left ventricle outflow tract obstruction, but cases of subaortic stenosis decades following a mitral valve replacement are exceedingly rare. Any abnormal positioning of a prosthetic valve can result in continuous turbulence leading to permanent deposition of fibrous tissue. We present a case of a 56-year-old female that underwent mechanical mitral valve replacement, due to severe rheumatic mitral valve disease, with recurrent admissions for dyspnea. Ultimately, she underwent a left heart catheterization and during pullback from the left ventricle to the aorta a 100-mmHg pressure gradient was noted below the level of the aortic valve suggestive of subaortic stenosis. The subaortic stenosis was found to be secondary to pannus formation from her mitral valve prosthesis placed over twenty years ago. <Learning objective: Subaortic stenosis secondary to pannus formation decades following a mechanical mitral valve replacement is exceptionally rare. The diagnosis of subaortic stenosis can be extremely difficult requiring high clinical suspicion, transthoracic and transesophageal echocardiography, computed tomography, and/or pullback pressure during left heart catheterization.>.