**3.4 Patent ductus arteriosus and aortopulmonary window**

122 Echocardiography – In Specific Diseases

overload. The MR can pass the primum ASD and results in LV to RA shunt, RA volume overload, and pulmonary overcirculation. In patients with complete AVSD, the presence of concomitant atrial and ventricular shunting can cause increased shunt flow. Pulmonary hypertension, secondary pulmonary vascular change, and increased pulmonary vascular resistance (PVR) can occur thereafter. The hemodynamic changes are affected by the magnitude and direction of shunt flow. There may be different directions of AV valve

The mid-esophageal four-chamber view of intraoperative TEE can demonstrate the defect of inferior part of atrial septum. Secundum ASD or patent foramen ovale (PFO) can be present in some patients. The broad-base MR jet not originating from the coaptation may suggest the presence of a cleft mitral valve (Figure 8). Cleft mitral valve may be demonstrated in transgastric basal short-axis view. Besides, the presence of ventricular shunting, sizes of both ventricle, ventricular function, magnitude and direction of AV valve incompetence, degree of AV valve straddling, presence of LVOT obstruction, degree of pulmonary hypertension, and associated cardiac anomalies must be evaluated preoperatively. The postoperative TEE exam should include the evaluation of ventricular function, AV valve competence, and the presence of residual shunt (Cohen et al., 2007). Because valvular regurgitation is quite pressure and load dependent, it is important that we take patient's volume status and cardiac contractility into consideration when comparing preoperative and postoperative regurgitation severity. If prosthetic valve is replaced, it is important to

regurgitation: LV-to-left atrium (LA), RV-to-RA, LV-to RA, or RV-to-LA.

check the function of prosthetic valve and the presence of paravalvular leak.

Fig. 8. Partial atrioventricular septal defect. The mid-esophageal four-chamber view demonstrates a primum atrial septal defect (atrial) and mitral cleft (double arrow) with

severe mitral regurgitation.

PDA is a postnatal communication between the main pulmonary trunk and descending thoracic aorta due to persistent patency of fetal ductus arteriosus (Schneider & Moore, 2006). Shunt flow is determined by diameter of PDA and the pressure gradient. The preoperative TEE can demonstrate the shunt flow in the ascending aorta short-axis view (Figure 9). The size of left-side chambers, ventricular function, valvular regurgitation, degree of pulmonary hypertension, and associated cardiac anomalies must also be evaluated. The postoperative TEE exam can be used to detect the presence of residual ductal flow.

Aortopulmonary defect, also known as aortopulmonary (AP) window, is a defect between ascending aorta and pulmonary artery. Without treatment, pulmonary system will be overloaded due to left to right shunt, and eventually develop pulmonary vascular occlusive disease. A significant portion of the patients have other associated cardiac anomalies. Preoperative TEE can detect a shunt between ascending aorta and PA (Figure 10). Evidence of pulmonary hypertension, ventricular function and size, defect size and shunt pressure gradient can be measured by intraoperative TEE. Surgical treatment usually involves aorta incision, defect visualization, and a patch is sutured to close the defect over the aortic side. The post-repair TEE exam should detect the presence of residual shunt, valvular competence, and ventricular function.

Fig. 9. The upper esophageal aortic arch long-axis view demonstrates the patent ductus arteriosus (arrow) connecting aortic arch and left pulmonary artery. Ao, aorta.

Intraoperative Transesophageal Echocardiography for Congenital Heart Disease 125

After repair, truncal valve function, residual intracardiac shunt and RVOT patency can be examined with color Doppler. Monitoring of ventricular function is important, because coronary artery may be compromised during pulmonary artery resection, RV-PA conduit reconstruction, and reimplantation of coronary arteries. Pulmonary hypertensive crisis and low cardiac output are potential threats for patients undergoing repair. RV function and severity of TR demonstrated in TEE exam can give anesthesiologist a guide for patient

Fig. 11. The mid-esophageal long-axis view shows a truncal vessel overrides the left

Postoperative TEE gives a direct evidence of anatomic site patency and LV function.

ventricle (LV) and right ventricle (RV) and gives rise to aorta and pulmonary artery (arrow).

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.

management.

Ao, aorta; PA, pulmonary artery.

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

Fig. 10. Aortopulmonary window as a defect (arrow) between ascending aorta and main pulmonary artery. Ao, aorta; PA, pulmonary artery.

#### **3.5 Truncus arteriosus**

Truncus arteriosus is caused by failure of truncal ridge and aortopulmonary septum to develop, forming aorta and PA. There is a single great vessel arising from a common semilunar valve, and a VSD. The truncal valve can have variable cusps, and valvular incompetence is not uncommon. Further classification is dependent on the existence of truncal septum, and the take-off position of pulmonary arteries. The VSD is caused by failure of conal septum to develop and rotate. It is usually large, non-restrictive, with superior border adjacent to truncal valve. PA is usually of normal size, but stenosis at origin site or diffuse hypoplasia may happen. Other common concurrent cardiac defects include right aortic arch, PDA, persistent left-sided SVC, ASD, and anomalous subclaivan artery.

Surgical repair encompasses separation of branched PA from truncus vessel, establishment of RV-PA continuity by RVOT reconstruction or RV-PA conduit, VSD closure, and repair of associated anomalies. Due to variable coronary anatomy, separation of PA from truncal vessel should be done with care. Mild to moderate truncal valve regurgitation is often tolerated, and will improve over time. However, severe regurgitation is a poor indicator for long term survival. If the truncal valve is severely incompetent, valve replacement should be considered.

Intraoperative TEE should focus on truncal valve morphology and function, anatomy of the main and branched pulmonary arteries, size and position of the intracardiac shunting, AV valve competence, ventricular function and the associated cardiac abnormalities (Figure 11).

Fig. 10. Aortopulmonary window as a defect (arrow) between ascending aorta and main

Truncus arteriosus is caused by failure of truncal ridge and aortopulmonary septum to develop, forming aorta and PA. There is a single great vessel arising from a common semilunar valve, and a VSD. The truncal valve can have variable cusps, and valvular incompetence is not uncommon. Further classification is dependent on the existence of truncal septum, and the take-off position of pulmonary arteries. The VSD is caused by failure of conal septum to develop and rotate. It is usually large, non-restrictive, with superior border adjacent to truncal valve. PA is usually of normal size, but stenosis at origin site or diffuse hypoplasia may happen. Other common concurrent cardiac defects include right aortic arch, PDA, persistent left-sided SVC, ASD, and anomalous subclaivan

Surgical repair encompasses separation of branched PA from truncus vessel, establishment of RV-PA continuity by RVOT reconstruction or RV-PA conduit, VSD closure, and repair of associated anomalies. Due to variable coronary anatomy, separation of PA from truncal vessel should be done with care. Mild to moderate truncal valve regurgitation is often tolerated, and will improve over time. However, severe regurgitation is a poor indicator for long term survival. If the truncal valve is severely incompetent, valve replacement should be

Intraoperative TEE should focus on truncal valve morphology and function, anatomy of the main and branched pulmonary arteries, size and position of the intracardiac shunting, AV valve competence, ventricular function and the associated cardiac abnormalities (Figure 11).

pulmonary artery. Ao, aorta; PA, pulmonary artery.

**3.5 Truncus arteriosus** 

artery.

considered.

After repair, truncal valve function, residual intracardiac shunt and RVOT patency can be examined with color Doppler. Monitoring of ventricular function is important, because coronary artery may be compromised during pulmonary artery resection, RV-PA conduit reconstruction, and reimplantation of coronary arteries. Pulmonary hypertensive crisis and low cardiac output are potential threats for patients undergoing repair. RV function and severity of TR demonstrated in TEE exam can give anesthesiologist a guide for patient management.

Fig. 11. The mid-esophageal long-axis view shows a truncal vessel overrides the left ventricle (LV) and right ventricle (RV) and gives rise to aorta and pulmonary artery (arrow). Ao, aorta; PA, pulmonary artery.
