Mitral Annulus Calcification

Mitral annulus calcification (MAC) is a chronic, degenerative process in the fibrous base of the mitral valve. Although MAC was initially thought to be an age-related degenerative process, there is accumulating evidence that other mechanisms, such as atherosclerosis and abnormal calcium-phosphorus metabolism, also contribute to the development of MAC. Despite its frequency, the clinical relevance of MAC is grossly underappreciated. Indeed, MAC is associated with an increased incidence of cardiovascular disease, mitral valve disease, arrhythmias, and mortality. MAC also influences the outcomes of cardiac surgery and interventions, and its clinical relevance may well increase substantially in the forthcoming era of transcatheter mitral valve replacement. In this paper, we review the available published data to provide a consistent, clinically relevant description of MAC on the basis of contemporary imaging. We describe the pathophysiological mechanisms contributing to the formation of MAC and the clinical implications of this disease entity.