Vascular Anomalies of the Chest

J. Paul Nielsen, MD, MPH

Aortic Arches• The aortic arches are a series of

paired arterial channels encircling the embryonic pharynx

Develop in the 4th week

Supply the developing pharyngeal arches

Arise from the aortic sac

Run dorsally, embedded in the mesenchyme of the pharyngeal arches and

Terminate in the right and left dorsal aortae

Arch of Aorta

Derived as:

•Proximal segment from aortic sac

•Middle segment from the left 4th aortic arch

•Distal segment from the left dorsal aorta

Subclavian Artery

•The right subclavian artery formed from the:

Right 4th aortic arch

Right dorsal aorta

Right 7th intersegmental artery

•The left subclavian artery formed from the left 7th intersegmental artery

Changes in the original aortic arch system

• Obliteration of:

• Most of the 1st & 2nd arches

• 5th arches completely

• Distal part of the right sixth arch

• The segment of both aorta lying between the 3rd & 4th arches

• The segment of right aorta lying between the 7th intersegmental artery & the fused dorsal aorta

Aortic Arch Anomalies

•Due to many changes involved in transformation of the embryonic pharyngeal arch system of arteries into the adult arterial pattern

•Most irregularities result from the persistence of parts of aortic arches that usually disappear, or from disappearance of parts that normally persists

•malformation of the aortic arch that results in vascular branches or major blood vessels encircling the trachea and esophagus.

•True rings: Double aortic arch (most common), double aortic arch with atretic left segment, right sided arch with abberant left subclavian

• In a double aortic arch, the two arches encircle the trachea and esophagus.

Vascular Rings

• left arch with abberant right subclavian (most common arch abnormality), Mirror image right arch, aortic coarctation, common origin of brachiocephalic and left common carotid artery (bovine configuration.), brachiocephalic artery compression.

Other non-true ring arch abnormalities

http://radiopaedia.org/articles/aortic-arch-variants

Double Arch of Aorta

• Characterized by a vascular ring encircling the trachea and esophagus, usually causing compression of both structures.

• The degree of compression varies

• Usually the right arch is larger and passes posterior to the esophagus

• The right common carotid and subclavian arteries arise separately from right arch

RSA LSA

LCCRCC

Brachiocephalic artery compression

syndrome

•Pulmonary sling occurs because of failure of formation of Left 6th aortic arch so there is absence of Left pulmonary artery

•The blood to the Left lung comes from an aberrant Left pulmonary artery which arises from Right pulmonary artery and crosses between esophagus and trachea

•Bronchial cyst may produce same finding on esophagus/trachea

•http://radiopaedia.org/articles/pulmonary-sling

Pulmonary Artery Sling

Spin Echo MR

Coarctation of Aorta

• Abnormality of the 4th and 6th arch

• An infantile coarctation is characterised by diffuse hypoplasia or narrowing of the aorta from proximal to the ductus arteriosus, associated with cyanosis of lower extremities due to left to right shunting through the PDA

• An adult coarctation in contrast is characterised by a short segment abrupt stenosis of the post-ductal aorta. It is due to thickening of the aortic media and typically occurs just distal ligamentum arteriosum (remnant of the ductus arteriosus), non-cyanotic, p/w lower extremity hyPOtension  

• Complications: Bacterial endocarditis common in 1st 5 decades, Aortic rupture 2~3rd decade subarachnoid hemorrhage(congenital Berry aneurysm)

Figure 8.  Tubular hypoplasia (preductal or infantile-type aortic coarctation).

Ferguson E C et al. Radiographics 2007;27:1323-1334

©2007 by Radiological Society of North America

Figure 7.  Localized (postductal or adult-type) aortic coarctation.

Ferguson E C et al. Radiographics 2007;27:1323-1334

©2007 by Radiological Society of North America

• Transposition of the great arteries, the most common cyanotic congenital heart lesion found in neonates, accounts for 5%–7% of congenital cardiac malformations.

• It is most common in infants of diabetic mothers. It is isolated in 90% of those affected and rarely is associated with a syndrome or an extracardiac malformation.

• in transposition of the great arteries, the pulmonary artery is situated to the right of its normal location and is obscured by the aorta on frontal chest radiographs. This malposition, in association with stress-induced thymic atrophy and hyperinflated lungs, results in the apparent narrowing of the superior mediastinum on radiographs, the most consistent sign of transposition of the great arteries.

Transposition of the Great Arteries

• The pulmonary veins fail to drain into the left atrium and instead form an aberrant connection with some other cardiovascular structure.

• Four types of TAPVR thus may be defined.In type I, the most common of the four (55% of cases), the anomalous pulmonary veins terminate at the supracardiac level. Typically, four anomalous pulmonary veins (two from each lung) converge directly behind the left atrium and form a common vein, known as the vertical vein, that passes anterior to the left pulmonary artery and the left main bronchus to join the innominate vein.

• Less commonly, anomalous drainage to the left brachiocephalic vein, the right superior vena cava, or the azygos vein occurs.

Total anomalous pulmonary venous return

• Type II TAPVR (30% of cases) involves a pulmonary venous connection at the cardiac level. The pulmonary veins join either the coronary sinus or the right atrium.

• Type III TAPVR (13% of cases) involves a connection at the infracardiac or infradiaphragmatic level. The pulmonary veins join behind the left atrium to form a common vertical descending vein, which courses anterior to the esophagus and passes through the diaphragm at the esophageal hiatus. This vertical vein usually joins the portal venous system but occasionally connects directly to the ductus venosus, the hepatic veins, or the inferior vena cava. Type III TAPVR is virtually always accompanied by some degree of obstructed venous return.

• Type IV TAPVR involves anomalous venous connections at two or more levels. In the most common pattern, the vertical vein drains into the left innominate vein, and the anomalous vein or veins from the right lung drain into either the right atrium or the coronary sinus. This pattern generally is associated with other major cardiac lesions.

Total anomalous pulmonary venous

return

•anomalous pulmonary vein that drains any or all of the lobes of the right lung. The so-called scimitar vein usually empties into the inferior vena cava but also may drain into the portal vein, hepatic vein, or right atrium

Partial anomalous pulmonary venous

return

The End

Links to cases•http://radiopaedia.org/articles/

aortic-arch-variants

•http://radiopaedia.org/articles/pulmonary-sling

Sources1. Aortic Arches. Zaidi, Zeenat.

http://www.docstoc.com/docs/125362680/12-Aortic-Arches2. Berdon WE. Rings, slings, other things: vascular compression of the

infant trachea updated from the midcentury to the millennium – the legacy of Robert E. Gross, MD, and Edward B. D. Neuhauser, MD. Radiology 2000;216:624–32

3. http://www.radiologyassistant.nl/en/p4718c7f2eb7cc/vascular-anomalies-of-aorta-pulmonary-and-systemic-vessels.html

4. http://www.hawaii.edu/medicine/pediatrics/pemxray/v6c19.html5. Classic imaging signs of congenital cardiovascular abnormalities.

http://radiographics.rsna.org/content/27/5/1323.full