Transcatheter mitral valve intervention, including repair and replacement, has been developed as an alternative treatment to mitral valve surgery with advanced technology in recent years, but the therapeutic indication is still limited to only a part of all, high-risk or inoperable patients. Although reoperative valve surgery is generally known to be associated with increased morbidity and mortality, conventional mitral valve surgery after previous aortic valve replacement is needed due to limited usage of catheter intervention as increasing of aged population. It is usually necessary to undergo redo median sternotomy with care as same as other reoperation, or right thoracotomy approach in some cases. In any cases, there is a tendency to poor visualization of the mitral valve, in especially, a view of anterior annulus due to rigid aortic prosthetic cuff. Of course, optimal visualization of the mitral valve is a successful key factor in reliable maneuver for either repair or replacement. Here we describe operative tips and pitfalls including operative indication, re-opening of the chest, left atrial approach.