Other Common Congenital Defects in Adults

Introduction

Due to improvements in surgical techniques and medical therapies in recent years, there has been an increase in survival to adulthood in those with complex congenital heart disease. While complex congenital heart disease requires a careful and individualized approach, there are some fundamental assessments that should occur based on anatomic diagnosis.

Segmental Anatomy

In patients with complex congenital heart disease, it is important to first assess the segmental anatomy of the heart. A systematic approach, which evaluates each level of blood flow—from the inferior vena cava (IVC) to the descending aorta—can be useful. Heart position is often best assessed with a subcostal sweep evaluating the location of the cardiac organ and the direction of the ventricular apex. This approach determines levocardia (leftward apex) from mesocardia (midline apex) from dextrocardia (rightward apex) ( Video 45.1 ). A careful evaluation of the systemic venous flow, atrial position, atrioventricular valves, ventricular morphology, pulmonary venous return, great vessel location, aortic arch, and descending aorta anatomy should follow. A brief review of the more common congenital heart lesions is presented here. A review of atrial septal defect (ASD) and ventricular septal defects (VSDs) is in Chapter 43, Chapter 44 . The full scope of complex congenital heart disease is addressed in the congenital echocardiography references listed at the end of this chapter.

Patent Ductus Arteriosus

The ductus arteriosus is a connection of the descending aorta and pulmonary arteries that functions to deliver oxygenated blood from the placenta to the pulmonary arteries in the fetal circulation. In the vast majority of newborns, the ductus closes by 1 month of age. However, a persistently patent ductus arteriosus (PDA) can occur (estimated at approximately 3/10,000 live births). With the rapid decline of pulmonary vascular resistance after birth, flow across the PDA is directed “left-to-right” from the aorta to the pulmonary arteries. If the PDA persists into adulthood, it results in overcirculation of blood through the pulmonary arteries, the pulmonary veins, the left atrium (LA), and the left ventricle (LV).

In an adult with a PDA, the findings include:

• 1.

  Dilated LA and LV without other etiology

• 2.

  Persistent flow across the PDA, which, on echocardiography, is best visualized in the parasternal short-axis image at the base of the heart or suprasternal notch imaging of the descending aorta

• 3.

  Right ventricle (RV) hypertension and pulmonary hypertension (as a result of Eisenmenger syndrome)

Diagnosis of a PDA is often made in the parasternal short-axis view with color Doppler evaluation. Imaging should focus on the pulmonary artery bifurcation ( Fig. 45.1 and Video 45.2 ). Flow from a PDA originates near the origin of the left pulmonary artery with continuous flow into the pulmonary artery shown by color Doppler. Usually, the color flow jet is visible, but visualization of the actual ductus is often difficult in adults. Suprasternal imaging of the aortic arch may be used with color Doppler with the imaging plane angulated towards the left pulmonary artery ( Video 45.3 ). Flow from the aorta to the pulmonary artery through the ductus can be visualized in this view.

Continuous-wave Doppler interrogation of the flow through a PDA with left-to-right shunting will demonstrate continuous flow from the aorta to the pulmonary artery. Flow velocity will vary between systole and diastole, with the higher flow velocities in systole, reflecting the larger pressure gradient. An estimation of the pressure gradient across the ductus can be helpful to determine whether pulmonary hypertension is present. Measurement of the peak velocity during systole (at or just after the R wave on electrocardiogram) reflects the pressure difference between aortic and pulmonary artery systolic pressure. Low velocity flow across a PDA suggests pulmonary hypertension.