Concomitant mitral regurgitation: an insidious cause of lowflow, low-gradient severe aortic stenosis

The combination of aortic stenosis (AS) and mitral regurgitation (MR) is frequent in patients with valvular heart disease. This entity raises important challenges with regard to severity grading and therapeutic management of both AS and MR. Long-standing afterload excess associated with severe AS induces hypertrophic remodelling, dilatation and/or dysfunction of the left ventricle (LV). Secondary MR may develop in this context as a result of mitral valve leaflet tethering and mitral annular dilatation. Because of the high prevalence of concomitant coronary artery disease, ischaemic MR is also frequent in the elderly population with AS. Elderly patients may also present primary MR as a result of degenerative and calcified mitral valves. In the Euro Heart Survey, multiple valve disease, as defined by at least two moderate valvular diseases, was observed in 20% of the patients with native valve disease and in 17% of those undergoing intervention. In a Swedish nationwide study, multiple and mixed valve diseases accounted for 11% of patients and the most frequent combinations were i) AS and MR, and ii) aortic regurgitation and MR. Despite the relatively high prevalence of the concomitance of AS and MR, there are limited data on the pathophysiology, diagnosis, and management of this multiple valve disease entity.