Transesophageal echocardiography showing leakage between the stent-post and the sewing ring before administration of protamine. Trans-gastric long axis view shows the diastolic oblique regurgitant flow toward the anterior mitral leaflet (red arrow) between the stent-post (white arrow) and the sewing ring (white arrow) before administration of protamine and immediately after CPB. The acoustic shadow (triangle) is accompanied by the stent-post and the sewing ring. LV: left ventricle; AML: anterior mitral leaflet.