Geometric change of mitral valve leaflets and annulus after reconstructive surgery for ischemic mitral regurgitation: Real-time 3-dimensional echocardiographic study

Abstract

Ischemic mitral regurgitation (IMR) is a functional regurgitation characterized by structurally normal leaflets and subvalvular apparatus and is an important complication after myocardial infarction that is associated with excess mortality. 1 Reconstructive surgery, which restores a more normal alignment between the mitral annulus and displaced papillary muscles, might be beneficial in patients with IMR. However, little is known about the 3-dimensional (3-D) geometric changes of mitral leaflets and annulus after such reconstructive surgery for patients with IMR. We developed novel software, named Anatomical Image Creation System (AICS), which allows 3-D visualization and quantitative analysis of the mitral leaflets and annulus by using transthoracic real-time 3-D echocardiography (RT3DE). 2 We already demonstrated the apparent tenting of the mitral leaflets with flattened annulus in patients with IMR using this system. 3 In the present study we evaluated the 3-D geometric changes of the mitral leaflets and annulus in patients after reconstructive surgery for IMR using AICS. Methods We studied 3 patients who underwent mitral ring annuloplasty and concomitant left ventricular (LV) restorative surgery for severe IMR and severe LV systolic dysfunction caused by coronary artery disease. All the RT3DE examination was performed 1 week before and 3 weeks after the operation. LV systolic function and degree of mitral regurgitation (MR) were quantified by using 2-dimensional echocardiography. Using the transthoracic volumetric image by the RT3DE system with AICS, we created 3-D images of the mitral leaflets and annulus in midsystole for the 3-D quantitative measurements. The mitral leaflets’ tenting volume was calculated as a volume enclosed between the 3-D annular plane and the mitral leaflets. Mitral annular size was measured by using those 3-D data sets as well (surface area, circumference, commissure-commissure diameter, and anterior-posterior diameter). Details of the 3-D image creation and measurements are described in our previous reports. 2,3 All 3 patients provided written informed consent to the study protocol, which was approved by the Committee for the Protection of Human Subjects in Research at Kawasaki Medical School.