Page 22 - Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

Chapter one. General introduction and outline of thesis
on cine steady-state, free-precession images using planimetry of the left ventricular cavity and the aortic forward volume measured on phase-contrast images. This is the most frequently used method and is not affected by the presence of concomitant regurgitant valve lesions.
(2) By calculating the difference between the left ventricular stroke volume and the right ventricular stroke volume measured using planimetry of the left and right ventricular cavities on cine steady-state, free-precession images. This method cannot be used when concomitant regurgitant valve lesions or significant shunts are present.
(3) By calculating the difference between the mitral inflow stroke volume and the aortic forward volume measured on phase-contrast images.
(4) Using four-dimensional flow CMR data with retrospective mitral valve tracking.
The mitral regurgitant fraction is calculated as the coefficient between the mitral regurgitant volume and the left ventricular stroke volume × 100. Quantification of mitral regurgitation with CMR provides important prognostic data. In 109 asymptomatic patients with moderate or severe mitral regurgitation, Myerson et al.[25] showed that a mitral regurgitant volume more than 55 ml and a regurgitant fraction more than 40% identified the patients who developed indications for surgical intervention during the following five years with a sensitivity of 72 and 76%, respectively, and a specificity of 87 and 74%, respectively. More recently, Penicka et al.[26▪▪] showed that the majority of the discrepancies between CMR and two-dimensional echocardiography in mitral regurgitant volume quantification occurred among patients with late systolic or multiple regurgitant jets and that patients with moderate mitral regurgitation based on two-dimensional echocardiography but with severe mitral regurgitation based on CMR analysis had higher rates of all-cause mortality or developed earlier indication for surgery as compared with patients with moderate mitral regurgitation assessed both with CMR and two-dimensional echocardiography.
The consequences of chronic severe mitral regurgitation on the left ventricular dimensions and function can be also assessed with CMR. Particularly, the presence of replacement fibrosis as assessed with LGE-CMR has been described in patients with primary mitral regurgitation. In the study by Kitkungvan et al.[27] patients with mitral valve prolapse had increased regional left ventricular replacement fibrosis, particularly in the segments adjacent to the posteromedial papillary muscle. The presence of replacement fibrosis may be further related to increased symptomatic ventricular arrhythmic events in patients with mitral valve prolapse [27]. In patients with secondary mitral regurgitation where the remodeling and dysfunction of the
20