Age and body surface area dependency of mitral valve and papillary apparatus parameters: assessment by real-time three-dimensional echocardiography

Real-time three-dimensional echocardiography (RT3DE) has been used to quantify mitral valve (MV) annular size and leaflet tenting parameters in small numbers of patients with different pathologies. We sought to establish normal values for RT3DE mitral annular, tenting, and papillary muscle parameters over a wide age range and to study their age and body surface area (BSA) dependency. Transthoracic wide-angled RT3DE images of the MV were acquired in 120 subjects (52 females, 68 males, age: 37 +/- 20 years) with normal left ventricular (LV) function, no risk factors, and less than or equal to mild mitral regurgitation. Custom software (RealView((R))) was used to trace the MV annulus, leaflets, and the papillary apparatus in mid-systole in 18 sequential cut planes obtained from the 3D data sets. Mitral valve annular area and height as well as tenting parameters (maximum and mean tenting height and mid-systolic tenting volume) were obtained and correlated with age and BSA. Wide inter-subject variability was noted in all parameters. Despite this variability, parameters directly affected by LV size were found to be BSA-dependent: MV annular area showed highest correlation with BSA (r = 0.78), followed by inter-papillary distance (r = 0.58) and postero-medial (PM) and antero-lateral (AL) papillary muscle annular distance (r = 0.57 and r = 0.46, respectively). Age did not correlate with either annular or tenting parameters, but showed moderate negative correlation with inter-papillary muscle angle (r = -0.52) and mild negative correlation with inter-papillary distance (r = -0.32), both normalized by BSA. Real-time three-dimensional echocardiography-derived MV annular, tenting, and papillary muscle parameters vary widely in normal subjects. When used clinically, normal values of parameters that are age- and/or BSA-dependent need to be adjusted accordingly.