Suprasternal view

The suprasternal view, also known as the suprasternal notch view, is obtained by placing the ultrasound probe in the suprasternal notch, pointing inferiorly and slightly posteriorly toward the mediastinum. The probe is placed with the marker towards the chin. 

In this view, we visualize the aortic arch in its long axis (or short axis if the probe is turned 90 degree clockwise), allowing assessment of:

• The transverse aortic arch and its curvature.

• The brachiocephalic vessels branching off the arch: the innominate artery, left common carotid, and left subclavian artery. The branching usually takes place towards the right shoulder in a left-sided aorta. 

• The descending aorta, visualized as a continuation of the arch.

• The pulmonary artery bifurcation if angled appropriately. 

• The pulmonary veins can me also seen in a crab view.

This view is particularly useful for evaluating aortic arch sidedness, identifying aortic coarctation, arch hypoplasia, vascular rings, and for confirming patency and flow direction through the aortic arch and descending aorta using color and spectral Doppler. In neonates and infants, where transthoracic windows are often optimal, the suprasternal view provides critical anatomical and functional information about the systemic outflow tract. It is also a good area to interogate the ductus arteriosus. 

Probe position

Anatomy

Echocardiography

Another example of an arch view with the corresponding colour box

Other examples of arch views with B-Mode and Colour

It is important to visualize and "open" the isthmus. It is often hard to tell if there is a narrowing in the presence of a patent ductus. As such, if the isthmus is narrowed, or if there is diffuse decrease in the caliber of the aorta, it is important to monitor clinically, as well as to ascertain ductal closure and arch caliber / diameters once ductus is closed. By quick rule of thumb, the isthmus diameter should be at least (if not bigger) than the weight of the baby in mm (example: 3kg = more than 3 mm). Best practice is to measure and to evaluate Z-scores of diameters based on normative tables. More on normative values here.

Holodiastolic retrograde flow in the post-ductal aorta:

• Patent ductus arteriosus with aorto to pulmonary shunt in diastole (diastolic steal; "left to right" in diastole); PVR < SVR

  • Aorto-pulmonary window in diastolic steal. Similar mechanism than the PDA. 

  • BTT Shunt. Similar mechanism than the PDA

  • Pott shunt. Usually placed for severe pulmonary arterial hypertension and unlikely to cause steal effect due to the PVR >>> SVR. However, there are rare situations where there is a combination of pulmonary vasodilators and resting status that may lead to occasional steal in diastole if PVR are momentarily infra-systemic. 

• Major aortopulmonary collaterals (MAPCAs). 

• Common Arterial Trunk ("Truncus Arteriosus") with diastolic steal

• Any congenital heart defect with a patent PDA (either naturally or induced by prostaglandins) and retrograde flow in diastole due to steal into the pulmonary vasculature. Ex: HLHS, Tricuspid Atresia, PAIVS, dTGA, etc.

• Aorto-Ventricular Tunnel (leads to a diastolic steal in the entire aortic arch, including ascending aorta). This includes tunnel to the left or the right ventricle.

• Significant Aortic Insufficiency/Regurgitation (leads to a diastolic steal in the entire aortic arch, including the ascending aorta). This includes ruptured sinus of Vasalva aneurysm.

• Cerebro-vascular dilatation (low of cerebral vascular resistance with  relative higher systemic vascular resistance in other organs, can lead to retrograde flow in diastole; seen in situations like neonatal hypoxic ischemic encephalopathy during the hyperluscency stage; status epilepticus exposed to anti-seizure medications)

• Coronary-cameral fistula. Coronary artery–to–venous or pulmonary artery fistulae. Coronary to sinusoids (RV-dependent coronary circulation) if the RV end-diastolic pressure falls (ex: post RVOT obstacle removal). 

• Cerebral arteriovenous malformation (such as in Vein of Galen malformation).

• Large non-cerebral AV malformations (e.g., hepatic, cutaneous in syndromic contexts) can similarly create a systemic diastolic steal pattern typically in the aortic area distal from the feeding vessel.

• Iatrogenic causes (e.g., ECMO circuit steal): Not directly a cardiac shunt, but VA-ECMO cannulation with altered systemic runoff can occasionally show diastolic retrograde aortic flow, especially if left ventricular ejection is minimal. 

• Pulmonary Arteriovenous Malformations (PAVMs): Rare in neonates but possible in hereditary syndromes or post-Glenn physiology. Leads to left-to-right steal at the capillary level — could produce retrograde aortic flow if significant enough.

Of note, ascending aorta retrograde flow in systole may be seen in situations where there is:

• Hypoplastic Left Heart Syndrome (HLHS): The ascending aorta is perfused retrogradely via the ductus arteriosus, as the left heart cannot generate forward flow. 

• Severe left ventricular (LV) dysfunction with minimal or absent systolic output: In extreme cases, LV systolic function is insufficient to produce antegrade flow, resulting in retrograde ductal perfusion of the ascending aorta (a physiology similar to HLHS). 

• Critical aortic stenosis (subvalvar, valvar, or supravalvar): Severe outflow tract obstruction can result in minimal systolic flow into the ascending aorta, with retrograde perfusion from the duct or collaterals. 

• LV inflow or diastolic filling impairment (non-systolic heart failure): Conditions such as hypertrophic cardiomyopathy, restrictive cardiomyopathy, or severe hypovolemia/preload reduction may impair LV filling to the point of markedly reduced stroke volume and low forward flow.

Pulmonary Artery Branching

If you turn the probe 90 degree with the marker towards the left shoulder, you will obtain a cross-section of the ascending aorta and often the bifurcation of the pulmonary artery into the right and left pulmonary arteries ("Mustache view" or "pants view"). 

Peripheral pulmonary stenosis (PPS) in newborns refers to narrowing or reduced caliber of the branch pulmonary arteries, typically involving the right and/or left pulmonary artery beyond the bifurcation of the main pulmonary artery. It is a common and usually benign finding in neonates, especially in preterm or low birth weight infants.Physiologic PPS is often seen in healthy newborns due to the angulation of the branching of the pulmonary arteries, which become more linear with growht (reducing the angle of branching). On echocardiography, PPS is characterized by flow acceleration with mild turbulence in the branch pulmonary arteries on color Doppler and elevated velocities (typically 1.5–2.0 m/s) on spectral Doppler.

Short Axis of the Aorta and Arch sided-ness

Superior Vena Cava

Normative Values of Aortic Arch Structures in Premature Infants

Reference: Normative Values of Aortic Arch Structures in Premature Infants. J Am Soc Echocardiogr 2017;30:227-32.)

Arch measurements