How to measure severity of mitral regurgitation

The recently revised American College of Cardiology/American Heart Association guidelines for valvular heart disease emphasise that surgery is now indicated for severe mitral regurgitation (MR), even in asymptomatic patients, provided that the valve anatomy is suitable for repair, and that surgery is performed in an experienced centre with at least a 90% chance of successful repair.1 A corollary to this recommendation is that it is important to determine accurately the severity of MR, since surgery is only indicated for severe MR. In 2003, the American Society of Echocardiography and the European Society of Echocardiography published recommendations for quantification of valvular regurgitation.2 This paper summarises those recommendations, as they pertain to MR. First, a theoretical framework for understanding the determinants of MR severity and how they relate to echocardiography will be presented. Then, the practical application of various echocardiographic techniques for assessing MR severity will be discussed. In accordance with the above guidelines, an emphasis will be made on integrating multiple parameters into the final determination of MR severity.2