Andersons pediatric cardiology 1064

When the valve is stenotic, there is limited excursion of the leaflets Turbulent flow distal to the truncal valve will be evident on color flow or continuous wave interrogation The parasternal long-axis sections will demonstrate the expected fibrous continuity between the leaflets of the truncal valve and the truncal leaflet of the mitral valve (see Fig 40.10; Video 40.1), the degree of dilation of the left ventricle, and the extent of biventricular hypertrophy Restriction of the ventricular septal defect will be seen in this view Continuous wave Doppler interrogation will record a drop in pressure across the defect, which may either be from left to right or from right to left, depending on the ventricular origin of the common trunk The parasternal short-axis section taken just above the level of the truncal valve demonstrates the pulmonary arteries as they arise from the common trunk In the so-called type I variant of common trunk, a short pulmonary arterial segment arises from the left lateral aspect of the common trunk and divides into right and left pulmonary arteries (Fig 40.11; Video 40.2) Stenosis at the origin of the right or left pulmonary arteries, or pulmonary arterial hypoplasia, will be evident in this section In the so-called type II pattern, the right and left pulmonary arteries arise from the posterior wall of the common trunk through separate but adjacent orifices (Fig 40.12) In practice, it is often difficult to distinguish these patterns, even in postmortem specimens In contrast, the type III variant is easily distinguished, the right and left pulmonary arteries arising from the common trunk via two widely separated orifices However, this variant is seen most frequently in the setting of pulmonary dominance, with the aortic segment of the common trunk being hypoplastic Other rarer origins of the pulmonary arteries must be anticipated, including atresia or even absence of one pulmonary artery The parasternal short-axis section will also identify the number of truncal valvar leaflets (Fig 40.13; Videos 40.3 to 40.5) Discontinuity between the tricuspid and truncal valvar leaflets will be seen in this cut when there is a muscular posteroinferior rim to the ventricular septal defect, expected in four-fifths of patients (Video 40.6) The parasternal short-axis section is also the plane used to interrogate the coronary arteries (Video 40.7) FIG 40.11 Echocardiographic image demonstrating the short axis of the arterial trunk (Tr) The right (RPA) and left (LPA) pulmonary arteries arise from a short common artery There is laminar flow in both pulmonary arteries that is of normal caliber FIG 40.12 Echocardiographic image taken from a parasternal window demonstrating the separate origin of the right pulmonary artery There is laminar flow within the pulmonary artery that is of normal caliber FIG 40.13 Echocardiographic image of the truncal valve viewed from a parasternal window In this patient the valve was functionally bicuspid The apical and parasternal four-chamber sections also demonstrate the large subarterial ventricular septal defect and the overriding of the truncal valve (Video 40.8) Color flow Doppler interrogation will usually demonstrate biventricular shunting across the defect Any truncal insufficiency will be evident in this view, whereas continuous wave Doppler will document any systolic gradient should the truncal valve be stenotic The diastolic drop in pressure between the common trunk and the ventricular mass can be demonstrated when there is valvar insufficiency The subcostal sections are unique in their ability to display most of the morphologic features of common arterial trunk The subcostal paracoronal sections demonstrate the ventricular septal defect, the nature of its posteroinferior rim, the overriding of the common trunk (Fig 40.14; Video 40.9), and the origin of both the ascending aorta and the pulmonary arteries (Figs 40.15 and 40.16) Oblique sections may reveal not only the origins of the pulmonary arteries, but also the integrity of the aortic arch (Fig 40.17) A right oblique section identifies the entirety of the proximal right pulmonary artery, whereas leftward rotation can be used to demonstrate the features of the left pulmonary artery They will also permit identification of any stenosis at the origins of the left and right pulmonary arteries, and will reveal rare findings such as crossed origins of the pulmonary arteries Anterior angulation demonstrates the morphology of the truncal valve, whereas color mapping reveals the severity of truncal regurgitation (Fig 40.18; Video 40.10) Characteristically,