Atrial septal defects and pulmonary arterial hypertension

Abstract

Atrial septal defects (ASD) are a common congenital heart defect. The majority of patient with ASDs often follow an uncomplicated course of events. However, a proportion of patients with ASDs, may have their condition complicated by pulmonary hypertension (PH), with a subsequent significant impact on management, morbidity and mortality. The presence of PH, influences the suitability for defect closure. In this review we describe the different types of ASDs, the classification of PH related to congenital heart disease (CHD), when ASD closure is contraindicated and the management of patients who develop pulmonary arterial hypertension (PAH), including the most extreme form, Eisenmenger syndrome (ES).

Keywords: Atrial septal defects (ASD); Eisenmenger syndrome (ES); left-to-right shunt; pulmonary arterial hypertension (PAH).

Figure 1

Evaluation of atrial septal defect size. (A) Shows a 2D transoesophageal echocardiographic image of a secundum ASD. (B) Shows a 3D transoesophageal echocardiographic image of the same defect demonstrating with greater accuracy the size of the defect and the strand crossing the defect not well seen on the 2D image.

Figure 2

Illustrates the microstructural changes, of smooth muscle hypertrophy and proliferation, implicated in the development of pulmonary vascular disease. (A) Demonstrates the normal anatomy of a pulmonary artery embedded within lung parenchyma. (B) Demonstrates in contrast the hypertrophy and fibrosis, resulting in vasoconstriction.

Figure 3

2D and 3D transoesophageal (A,B,C,D) echocardiographic images and 2D transthoracic four chamber images (E,F) of pre (A,C,E) and post (B,D,F) ASD closure with a fenestrated device (B,D,F) in a patient with pulmonary hypertension (A; Doppler signal inset) and left ventricular disease. Improvements in right ventricular dilatation post ASD closure are seen in (F). ASD, atrial septal defect.