Mitral annulus calcification--a window to diffuse atherosclerosis of the vascular system

Mitral annulus calcification (MAC) is a chronic, non-inflammatory, degenerative process of the fibrous support structure of the mitral valve. It occurs more often in women and the elderly. MAC is associated with known atherosclerotic risk factors such as diabetes mellitus, hypertension and hypercholesterolemia. It is also known that patient with MAC have higher prevalence of left atrial and left ventricular enlargement, hypertrophic cardiomyopathy, atrial fibrillation, aortic valve calcification and stenosis, various cardiac conduction defects, bacterial endocarditis, cardiovascular events and stroke, though the etiological basis is unknown. Pathological studies from the 80s present a theory that MAC is a form of atherosclerosis. In order to test this theory we conducted during the last years a few clinical studies to examine the association of MAC and known atherosclerotic phenomena. We found higher prevalence of aortic atheroma in patients with MAC and atheroma thickness. We also found in MAC patients higher prevalence of carotid artery stenosis, coronary artery stenosis, peripheral artery stenosis and higher levels of beta2-Glycoprotein I antibodies in patients with MAC thickness equal or greater than 5 mm. These studies support the theory that MAC is a form of atherosclerosis and define a group of patients with higher prevalence of atherosclerotic disease in multiple blood vessels. The purpose of this review is to summarize the data concerning MAC and atherosclerotic processes, emphasizing that MAC in itself may be an atherosclerotic process.