Role of Echocardiography in Mitral Valve Surgery

When performing transesophageal echocardiography for the purpose of assessing mitral valve anatomy before intended mitral valve repair, it is important that a thorough and detailed evaluation of the mitral valve be undertaken in a systematic fashion. The primary purpose of the examination is to determine the underlying anatomic abnormality responsible for the regurgitation or stenosis. It is important to recognize that there are three different viewing perspectives on mitral valve anatomy (Fig. 19.14). The surgeon will be viewing the mitral valve from within the left atrium so that the anterolateral commissures will be to the left of the field of view and the medial commissures to the right. When viewed with either transesophageal or transthoracic echocardiography, this orientation will be reversed (assuming traditional recommended viewing formats on a video screen). Also, depending on whether the reference is a transthoracic or transesophageal echocardiogram, the anterior and posterior leaflets of the mitral valve will vary in position compared with the surgical perspective. Figure 19.14 depicts all three perspectives of the mitral valve in relation to the aorta and left atrial appendage.