Open Transcatheter Mitral Valve Implantation Into the Native Mitral Valve for Inoperable "Big MAC".

Because of the growing population of older adult patients, the prevalence of severe mitral annulus calcification ("big MAC") is increasing. The surgical techniques used to treat big MACs are technically demanding; despite the technical aspect, up to one-third of patients are considered too high risk for conventional surgery but are candidates for the coulisse technique, which is a procedure that implants a transcatheter valve into a native mitral annulus. The anterior leaflet is unfolded, thus reducing the risk of obstructing the left ventricular outflow tract and for paravalvular leak and avoiding valve migration. Preoperative planning, based on a computed tomography scan, is mandatory.