[Dynamic obstruction of the left ventricular outflow tract by prosthesis dysfunction]

We report on a case of dynamic left ventricular (LV) outflow tract obstruction combined with a prosthetic valve dysfunction 13 years following mitral valve replacement with a Hancock bioprosthesis in a 46-year-old patient. Previously, repeated echocardiographic controls had been performed at regular intervals and the prosthesis had been found to be oversized and seated in abnormal position, with projection of the struts into the LV outflow tract. Moreover, a mild chronic LV outflow tract obstruction had been diagnosed upon intermittent findings of relatively high velocity in the outflow tract. Clinically, however, the patient had been stable and the function of the prosthesis had been good. With the onset of the mitral regurgitation due to prosthesis failure, a dynamic obstruction to LV outflow occurred, with severe narrowing of the LV outflow tract by a strut of the bioprosthesis during systole. Subsequently, a low cardiac output syndrome developed. The patient was referred for a mitral valve reoperation. The valve was replaced with a Sorin Bileaflet Carbon prosthesis. On the setting of a mild chronic LV outflow obstruction due to the oversized prosthesis and its abnormal position, hypercontractile cardiac function as a result of mitral regurgitation may have caused the dynamic and symptomatic LV outflow tract obstruction.