**3.6 Coarctation of aorta and interrupted aortic arch**

Coarctation of aorta (CoA) is characterized by narrowing of aortic lumen due to thickening or infolding of aortic media (Rosenthal, 2005). Interrupted aortic arch (IAA), on the other hand, is complete discontinuity between two parts of aortic arch. These lesions lie closely to PDA or ligament arterioum. In patients with CoA, the defect can be isolated, or associated with VSD or other complex cardiac disease. The LV afterload is increased in patients with CoA. The site and extent of the stenosis may be seen in upper esophageal level during TEE exam (Figure 12). However, preoperative TEE exam can offer valuable information for other associated anomalies, such as biscupid aortic valve, Shone's complex, and VSD. Surgical treatment includes resection of stenotic area with end-to-end anastomosis, extended resection with primary anastomosis, subclavian flap aortoplasty, and patch augmentation. Some patients have balloon angioplasty and stent insertion in intervention units. Postoperative TEE gives a direct evidence of anatomic site patency and LV function.

Intraoperative Transesophageal Echocardiography for Congenital Heart Disease 127

the connection site of pulmonary veins, anomalous pulmonary venous return (APVR) can be classified as supracardiac type, cardiac type, infracardiac type, and mixed type. In supracardiac type APVR, confluence of pulmonary veins unites to an ascending vertical vein and joins the innominate vein, and then drains into SVC and RA. Sometimes the vertical vein bypasses the innominate vein and joins SVC directly. The connection site between vertical vein and innominate vein or SVC is prone for pulmonary venous obstruction. In patients with cardiac type APVR, the pulmonary vein confluence drains into the coronary sinus, and then to the RA. Some of the patients will have pulmonary veins going directly to RA. In the infracardiac type, the pulmonary vein confluence drains into a descending vertical vein, goes down across diaphragm to portal vein or hepatic vein, and

The pathophysiology is similar to that of ASD in patients with PAPVR. The degree of shunt is determined by the numbers of anomalous pulmonary venous connections. In TAPVR, all of the pulmonary veins drain into RA and there is no pulmonary venous return in LA. Blood in LA is derived from PFO or ASD, which is mixed deoxygenated blood, therefore the patients are cyanotic. In patients with small size or restrictive ASD, the systemic circulation will decrease significantly. In patients with large or nonrestrictive ASD, the magnitude of shunt is determined by the relative ratio of PVR and systemic

The pulmonary veins are in the posterior portion of the heart, which makes TEE a valuable tool for optimal imaging and Doppler examination. However, proper probe size should be considered to avoid pulmonary veins compression by probe insertion. PAPVR should be suspected whenever a sinus venous ASD is present. The distinguishable TEE feature of TAPVR includes absence of pulmonary venous connection to LA, identification of alternate pulmonary venous drainage site, and RV overload (Figure 13). The presence of pulmonary venous obstruction, pulmonary hypertension and associated cardiac anomalies must be evaluated. The post-repair TEE exam should check the ventricular and valvular function,

signs of pulmonary hypertension, and presence of pulmonary venous obstruction.

Fig. 13. Anomalous pulmonary venous return. (A) Cardiac type: the modified midesophageal four-chamber view demonstrates the drainage of pulmonary vein (PV) into coronary sinus (CS) and then right atrium (RA). (B) Supracardiac type: the modified midesophageal five-chamber view shows the dainage of PV into superior vena cava (SVC)

then comes back to RA with IVC.

vascular resistance (SVR).

(arrow). RV, right ventricle; Ao, aorta.

Fig. 12. Upper esophageal aortic arch long-axis view shows coarctation of aorta (arrow). Ao, aorta.

IAA is classified by its interruption location into three types: type A, interruption is distal to left subclavian artery; type B, interruption is between left subclavian artery and left common carotid artery; and type C, interruption is proximal to left carotid artery. The arterial circulation proximal to the interruption is supplied by the LV output. The RV output supplies the arterial circulation distal to the interruption via the ductus arteriosus. Patients usually have PDA, VSD, and aortic valve abnormalities. The VSD is usually conoventricular type with a posterior conal septum malalignment, which causes LVOT obstruction at either subvalvular or valvular level.

Preoperative TEE can be used to evaluate the morphology of aortic arch and PDA. Other coexisting defects should be carefully explored. Size of LVOT and aortic valve should be measured. Failure to detect LVOT obstruction is likely to result in persistent heart failure postoperatively. Surgical treatment for IAA is more complex than simple CoA. Current favorable approach is one-stage repair of interruption, and total correction of intracardiac abnormalities. However, if LVOT obstruction prohibited one-stage correction, modified Norwood operation such as Damus-Kaye-Stansel connection with atrial septectomy may be needed. Postbyapss TEE exam should survey for anastomotic stenosis, aortic or subaortic obstruction, residual atrial or ventricular shunts, and signs of pulmonary hypertension.

#### **3.7 Anomalous pulmonary venous return**

Partial or total anomalous pulmonary venous return (PAPVR/TAPVR) indicates that some or all of the pulmonary veins enter systemic venous circulation instead of LA. According to

Fig. 12. Upper esophageal aortic arch long-axis view shows coarctation of aorta (arrow). Ao,

IAA is classified by its interruption location into three types: type A, interruption is distal to left subclavian artery; type B, interruption is between left subclavian artery and left common carotid artery; and type C, interruption is proximal to left carotid artery. The arterial circulation proximal to the interruption is supplied by the LV output. The RV output supplies the arterial circulation distal to the interruption via the ductus arteriosus. Patients usually have PDA, VSD, and aortic valve abnormalities. The VSD is usually conoventricular type with a posterior conal septum malalignment, which causes LVOT obstruction at either

Preoperative TEE can be used to evaluate the morphology of aortic arch and PDA. Other coexisting defects should be carefully explored. Size of LVOT and aortic valve should be measured. Failure to detect LVOT obstruction is likely to result in persistent heart failure postoperatively. Surgical treatment for IAA is more complex than simple CoA. Current favorable approach is one-stage repair of interruption, and total correction of intracardiac abnormalities. However, if LVOT obstruction prohibited one-stage correction, modified Norwood operation such as Damus-Kaye-Stansel connection with atrial septectomy may be needed. Postbyapss TEE exam should survey for anastomotic stenosis, aortic or subaortic obstruction, residual atrial or ventricular shunts, and signs of pulmonary hypertension.

Partial or total anomalous pulmonary venous return (PAPVR/TAPVR) indicates that some or all of the pulmonary veins enter systemic venous circulation instead of LA. According to

aorta.

subvalvular or valvular level.

**3.7 Anomalous pulmonary venous return** 

the connection site of pulmonary veins, anomalous pulmonary venous return (APVR) can be classified as supracardiac type, cardiac type, infracardiac type, and mixed type. In supracardiac type APVR, confluence of pulmonary veins unites to an ascending vertical vein and joins the innominate vein, and then drains into SVC and RA. Sometimes the vertical vein bypasses the innominate vein and joins SVC directly. The connection site between vertical vein and innominate vein or SVC is prone for pulmonary venous obstruction. In patients with cardiac type APVR, the pulmonary vein confluence drains into the coronary sinus, and then to the RA. Some of the patients will have pulmonary veins going directly to RA. In the infracardiac type, the pulmonary vein confluence drains into a descending vertical vein, goes down across diaphragm to portal vein or hepatic vein, and then comes back to RA with IVC.

The pathophysiology is similar to that of ASD in patients with PAPVR. The degree of shunt is determined by the numbers of anomalous pulmonary venous connections. In TAPVR, all of the pulmonary veins drain into RA and there is no pulmonary venous return in LA. Blood in LA is derived from PFO or ASD, which is mixed deoxygenated blood, therefore the patients are cyanotic. In patients with small size or restrictive ASD, the systemic circulation will decrease significantly. In patients with large or nonrestrictive ASD, the magnitude of shunt is determined by the relative ratio of PVR and systemic vascular resistance (SVR).

The pulmonary veins are in the posterior portion of the heart, which makes TEE a valuable tool for optimal imaging and Doppler examination. However, proper probe size should be considered to avoid pulmonary veins compression by probe insertion. PAPVR should be suspected whenever a sinus venous ASD is present. The distinguishable TEE feature of TAPVR includes absence of pulmonary venous connection to LA, identification of alternate pulmonary venous drainage site, and RV overload (Figure 13). The presence of pulmonary venous obstruction, pulmonary hypertension and associated cardiac anomalies must be evaluated. The post-repair TEE exam should check the ventricular and valvular function, signs of pulmonary hypertension, and presence of pulmonary venous obstruction.

Fig. 13. Anomalous pulmonary venous return. (A) Cardiac type: the modified midesophageal four-chamber view demonstrates the drainage of pulmonary vein (PV) into coronary sinus (CS) and then right atrium (RA). (B) Supracardiac type: the modified midesophageal five-chamber view shows the dainage of PV into superior vena cava (SVC) (arrow). RV, right ventricle; Ao, aorta.

Intraoperative Transesophageal Echocardiography for Congenital Heart Disease 129

Fig. 15. Tetralogy of Fallot. The right ventricle (RV) inflow-outflow view shows a ventricular

Ebstein's anomaly is characterized by abnormal attachment of septal and posterior tricuspid leaflets in the RV, away from normal tricuspid annulus position. The anterior leaflet is normally attached at annulus, but morphologically enlarged, "sail-like", and tethered to RV wall. The anterior leaflet may functionally obstruct the RVOT. Because tricuspid valve orifice is displaced downward to RV cavity at the junction of the inlet and trabecular components, the proximal portion of the RV is functionally integrated into RA, termed atrialized RV. The severity of hemodynamic compromise is related to the downward displacement of the leaflets, the degree of outflow tract obstruction and valvular regurgitation, the severity of myocardial dysfunction, and other concomitant cardiac abnormalities. RV output is decreased by decreased RV volume and varying degrees of RVOT obstruction. The most commonly accompanied disease is secundum type ASD or PFO. Cyanosis will occur if there is a large right-to-left shunt. Clinical presentation varied extremely from normal tricuspid function found incidentally on autopsy to severe cyanosis, compromised cardiac function, and fetal death. Appropriate surgical intervention depends on the age at presentation and associated anomalies. Tricuspid valve is either repaired or replaced depending on the extent of atrialized ventricle and morphology of tricuspid valve.

septal defect (D) and infundibular pulmonary stenosis (arrow). Ao, aorta.

Single ventricle repair may be performed in patients with poor RV condition.

Considering the variety of the disease entity and different surgical approaches, intraoperative TEE has a significant role in preoperative evaluation and decision making. In mid-esophageal four-chamber view, we can calculate the displacement index, which is the apical displacement of tricuspid valve septal leaflet in millimeters indexed to body surface area. A displacement index more than 8mm/m2 is a sensitive predictor of Ebstein's anomaly

**3.9 Ebstein's anomaly** 
