Usefulness of intraoperative real-time three-dimensional transesophageal echocardiography in preprocedural evaluation of cortriatriatum -a case report-
A 44-year-old female underwent elective tricuspid valve repair and atrial septal defect (ASD) closure due to known congenital cardiac anomalies suggesting cortriatriatum. These anomalies comprised tricuspid insufficiency, interatrial septal defects, and an abnormal membrane in the LA in preoperative 2D TEE. She presented with peripheral edema, especially in the lower extremities, frequent upper respiratory tract infections and mild exertional dyspnea without any other remarkable medical history.\nAnesthetic induction and tracheal intubation was performed using target-controlled infusion (TCI) of propofol (effect site 2.0 mcg/ml) and remifentanil (plasma 15-20 ng/ml) as well as bolus rocuronium 0.9 mg/kg, adjustment of TCI-propofol (effect site concentration of 1.0-1.2 mcg/ml to maintain BIS value 40-60) and cisatracurium infusion (0.2 mcg/kg/min) were followed for anesthesia maintenance. After anesthetic induction, pulmonary artery catheter placement was placed in the right internal jugular vein under ultrasound-guidance. A 3D TEE probe (X7-2t transducer; Philips Healthcare, Andover, MA, USA) was placed and connected to TEE console (iE33™, Philips Healthcare, Andover, MA, USA), intraoperative 2D and 3D TEE examinations were then performed. The 2D TEE examination showed an enlarged right atrium (RA); a relatively small and septated LA with a solid, thin echogenic membrane (indicating the LA diaphragm) separating the LA into two distinct chambers; a larger (proximal) LA chamber in the superior aspect; and a small (distal) LA chamber in the inferior aspect (). The distal LA chamber had a mitral valve (MV) apparatus and communicated with the left ventricle (LV). Although intraoperative 2D TEE findings corresponded quite well with preoperative TTE findings, they could not provide the detailed information regarding the extent of the LA diaphragm and the shape of the diaphragmatic defect. Important information for understanding the intracardiac flow pattern of the systemic and pulmonary circulation could not be provided by using 2D TEE alone. Additional real time 3D "en face" image and cropped images from the real time 3D volume images facilitated a complete understanding of the whole features of the complex anomalies of this case, including the shape and size of the diaphragm in a considerably easier and faster manner. 3D TEE showed that the RA dimension was much larger than the LA dimension with a thin membranous diaphragm traversing the whole LA to form a horizontal roof between the proximal and distal LA chambers. The LA diaphragm did not have any holes: the proximal LA chamber communicated with the RA through a 2 cm defect in the interatrial septal area, which allowed the drainage of pulmonary venous blood from the proximal LA into the enlarged RA and thus contributed to the role of the RA as a mixing chamber for systemic, pulmonary, and coronary venous blood. The mixed blood in the RA then flowed through the tricuspid valve to reach the right ventricle, as well as through a 4 cm ASD to reach the distal LA chamber. The relatively small distal LA served as a functional LA with a left atrial appendage and MV apparatus at the bottom ().\nRight atriotomy was performed through a median sternotomy after initiation of moderate hypothermic cardiopulmonary bypass. A self-retaining retractor was used to maximize the exposure of all intracardiac structures, including the LA diaphragm, atrioventricular valve apparatus, and coronary and pulmonary venous openings. After confirming the above determinations by surgical perspectives, the following procedures were performed; full resection of the LA diaphragm, tricuspid valve ring annuloplasty, removal of the diaphragmatic defect by constructing of a new interatrial septum using a bovine pericardial patch, and closure of the ASD (). The newly constructed septum separated the pulmonary and systemic flow which draining into LA and RA, respectively.