Incidental moderate mitral regurgitation in patients undergoing coronary artery bypass grafting: update on guidelines and key randomized trials

Incidental moderate mitral regurgitation (MR) in patients presenting for coronary artery bypass grafting (CABG) is not only common but also probably adversely affects clinical outcome. The echocardiographic evaluation of incidental MR must be comprehensive and integrated, as it remains a cornerstone in management decisions. Current guidelines support surgical mitral intervention in this setting as a reasonable option, reflecting clinical equipoise towards moderate MR in the setting of planned CABG. There are currently 2 major randomized trials in progress that will test whether surgical correction of moderate MR combined with CABG improves major clinical outcomes as compared to CABG alone. These landmark trials will be completed in the near future. In the interim, significant progress in the fields of cardiac resynchronization therapy, transcatheter mitral valve intervention, and minimally invasive mitral valve surgery promise to affect the management alternatives for moderate MR in patients undergoing CABG regardless of operative risk. It is likely that in the coming decade there will be less tolerance for incidental moderate MR given its already known outcome effects and the multimodal interventions that continue to mature with better safety profiles.