Mitral Annular Calcification

Dr Om P Yadava, CEO and Chief Cardiac Surgeon of the National Heart Institute in New Delhi, India, and Editor-in-Chief of the Indian Journal of Thoracic and Cardiovascular Surgery, discusses mitral annular calcification with Dr Carlos Mestres, Senior Cardiothoracic and Vascular Surgeon of the University Hospital Zurich in Switzerland.

Whether mitral annular calcification (MAC) is a disease itself or just a bystander, it is still a controversial subject. It is not the same as the calcified mitral valve, which is normally associated with rheumatic pathology. The most extensive study was carried out by Ariela Pomerance of England in 1970 (1), which showed that the incidence of MAC increased exponentially beyond the age of 70 years and was more common in women. The exact pathogenesis is not known. It seems to be an inflammatory pathology, and chlamydial infection has been implicated. Atherosclerosis and metabolic syndrome may also play a role. Even caseous mitral valve has been implicated (2). Dr Mestres laments the lack of epidemiological data in the field and its exact incidence. He comments that athough the calcification in itself is a benign phenomenon, when it comes to actual operating, it can provide significant challenges. The risks can be daunting, especially in certain procedures, like enlargement of the aortic root in the presence of a calcified mitral annulus. Though echocardiography, computed tomography (CT), and magnetic resonance imaging can all be used for diagnosis, CT imaging is probably the most useful and fundamental (3). However, in certain patients, the use of fusion (multimodality) technology may be more informative (3).

Various options are available to handle MAC, including total decalcification and reconstruction of the annulus using a pericardial patch, supra-annular placement of the valve, or partial decalcification. Transcatheter options are also very relevant to these patients.

References

1. Pomerance A. Pathological and clinical study of calcification of the mitral valve ring. J Clin Pathol. 1970;23(4): 354–361.
2. Elgendy IY, Conti CR. Caseous calcification of the mitral annulus: a review. Clin Cardiol. 2013;36(10):E27-31.
3. Shah BN, Babu-Narayan S, Li W, Rubens M, Wong T. Severe mitral annular calcification: insights from multimodality imaging. Tex Heart Inst J. 2014;41(2):245-247.