VASCULAR RING AND SLING

Presenter- Dr.Jyotindra SinghNIMS,HYDERABAD

INTRODUCTIONAortic arch anomalies producing tracheo esophageal

constriction account for 1 to 2% of all congenital heart disease.

Vascular ring is a congenital anomaly in which the aortic arch and its branches completely or incompletely encircle and compress the trachea or esophagus, or both.

Vascular sling is a congenital anomaly in which the left

pulmonary artery arises from the right pulmonary artery

extrapericardially (anomalous left pulmonary artery), courses

to the left behind the tracheal bifurcation and in front of the esophagus to reach the left lung hilum, and forms a sling

around the trachea.

HISTORICAL ASPECTS The condition of double aortic arch was apparently first described by Hommel in 1737 (cited by Turner) and a century later by Von Siebold.

The complex development and regression of the aortic arches during fetal development was elucidated by Congdon in 1922,

Wolman is credited with describing the syndrome of tracheal and esophageal compression produced by a double arch in 1939.

Stimulus for modern interest in these anomalies was prompted by the first

surgical correction of a double aortic arch by Gross in 1945.

The basis for radiologic diagnosis was initially described by Neuhauser.

HISTORICAL ASPECT1948, Edwards introduced the hypothetical double aortic arch scheme to conceptualize the numerous anomalies of the arch complex.

This was further elaborated by Kirklin and Clagett in 1950 and by Stewart, Kincaid, and Edwards in 1964.

In 1951, Barry provided a clear anatomic summary and review of Congdon's basic work.

In 1999, Momma and colleagues followed by McElhinney and colleagues identified chromosome 22ql l deletions associated with isolated anomalies of laterality or branching of the aortic arch

EMBRYOLOGYBy 5 weeks of fetal development, the primordial heart tubes have fused and six aortic (branchial) arches have formed between the ventral roots and dorsal aortae

During normal development, persistence of the left fourth aortic arch forms the arch of the aorta and proximal left subclavian artery.

The right fourth aortic arch forms the innominate and right subclavian arteries.

Involution of the distal right aorta results in an unpaired single aortic arch.

Aortic --sac

Fourth Pair

RIGHT: Becomes the proximal part of the right subclavian artery

LEFT: Forms part of the arch of aorta

Arch of AortaDerived 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

Sixth PairRIGHT:• Proximal part: persists as

the proximal part of the right pulmonary artery

• Distal part: degenerates

LEFT:• Proximal part: persists as

the proximal part of the left pulmonary artery

• Distal part: forms ductus arteriosus, a shunt between pulmonary artery and dorsal aorta

Group I-Complete vascular ring

Double aortic arch

Right aortic arch with retroesophageal component

Mirror-image branching with retroesophageal ligamentum arteriosum

Retroesophageal left subclavian artery with ligamentum arteriosum

Retroesophageal left innominate artery

Right aortic arch with retroesophageal left subclavian artery

Left aortic arch and right descending aorta with right ligamentum arteriosum or patent ductus arteriosus

Cervical aortic arch complex

Group II -Incomplete vascular ring

Left aortic arch and retroesophageal right subclavian artery

Tracheal compression by innominate or left common carotid artery

Ductus arteriosus sling

Malrotation of heart with patent ductus arteriosus

GROUP III- Pulmonary artery Sling

DOUBLE AORTIC ARCHHOW IT IS FORMED ?

WHAT IS DOUBLE AORTIC ARCH?

HOW IS VASCULAR RING FORMED?

ORIGIN OF VESSELS?

RIGHT DOMINANT,LEFT DOMINANT,BALANCED?

 

Double aortic archA double aortic arch is the most common complete vascular ring that causes tracheoesophageal compression.

Patients typically present in the first months of life with symptoms of stridor, respiratory distress, and a cough that sounds like a seal's bark. A simple cold may precipitate severe respiratory difficulty.

In patients with double aortic arch, the ascending aorta arises normally, but as it leaves the pericardium it divides into two branches, a left and a right aortic arch that join posteriorly to form the descending aorta.

The left arch passes anteriorly and to the left of the trachea in the usual position and is joined by the ductus arteriosus (or more often a ligamentum arteriosum), where it becomes the descending aorta.

The right aortic arch passes to the right and then posterior to the esophagus to join the left-sided descending aorta, thus completing the vascular ring .

DOUBLE AORTIC ARCH

Two-thirds of these infants, the right-sided (posterior) arch is dominant, and in one-third, the left-sided (anterior) arch is dominant. Rarely, the arches are of equal size (balanced arches).

The right arch gives origin to two vessels, the right common carotid and right subclavian arteries,

The left arch gives origin to the left common carotid and left subclavian arteries, in that order.

“Four artery sign.” - When the two dorsal subclavian arteries arise directly from the aorta and not from a brachiocephalic artery.

2 dorsal subclavian arteries and 2 ventral carotid arteries spaced evenly around the trachea.

Double Aortic Arch

Both arches patent Symmetrical origin

Atretic L arch distal to the origin of L SCA

Atretic segment between L CCA and L SCA

VARIANTSThe right aortic arch is often (50%) larger (right dominant) than the left arch, which usually becomes narrow or atretic in its distal part beyond the origin of the left subclavian artery .

This portion may remain patent or be represented by a fibrous chord that joins the descending aorta, often at the site of a diverticulum.

Less commonly (25%) the left aortic arch is larger (left dominant) than the right arch, which, although smaller in its distal part after the origin of the right subclavian artery, is rarely atretic .

Size of the right and left aortic arches is about equal (balanced) in about 25% of cases.

Associated cardiovascular anomalies are not common, but include tetralogy of Fallot and transposition of the great arteries.

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5. Double Aortic ArchClinical features

– vascular ring – symtoms depend on tightness of ring

When both arches widely patent tight ring stridor in 1st wk

Atretic L arch loose ring present at 3-6/12 week or later

Rarely double AA present in adulthood - swallowing/resp. syms

DOUBLE AORTIC ARCHCHILD WITH RECURRENT PNEUMONIA

 

 

Double Aortic Arch. Frontal chest shows impression on right-side of barium-filled esophagus from higher right-sided arch and below it an impression on the left-side of the esophagus from left-sided arch.

Lateral film shows anterior displacement of both trachea and esophagus.

SURGICAL APPROACH & PRINCIPLE

Surgical approach is determined by which arch is dominant.

When the right arch is dominant (75%)- left thoracotomy.

When the left arch is dominant (18%)- right thoracotomy.

When the arches are balanced (7%), - left thoracotomy is preferred.

If the patient has a significant intracardiac lesion-median sternotomy.

MRI / CT scan shows Right posterior arch is smaller- Right thoracotomy

SURGICAL STEPS What surgical approach taken?

Muscle-sparing technique,-elevating the serratus anterior and the latissimus dorsi

Fourth intercostal space.

How is lung retracted?

Before opening pleura ,what structures to identify?

Relation of vagus nerve?

How is pleura opened?

Surgical stepsLigamentum arteriosum identified?

Isolation of posterior arch

Which arch to preserve?

Site of division?--

Caution before clamp/vascular division?

Is mediatinal pleura sutured?

Post operative care

High humidity to loosen secretions;

oxygen therapy when needed, as monitored by pulse oximetry;

chest physiotherapy;

and nasopharyngeal suctioning.

to achieve early extubation.

Nebulization.

Right Arch of Aorta

Occurs when the entire right aortic arch persists &the segment of left dorsal aorta distal to the 7th intersegmental artery involutes

TYPES: Without retropharyngeal component:

The DA passes from right pulmonary artery to right arch of aorta. No effect on the trachea & esophagus

With retropharyngeal component: The right arch lies posterior to esophagus.

The attachment of DA to distal part of the arch of aorta forms a ring around the trachea & esophagus and may lead to their compression

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Type I –RAA without retroesophageal component

• Mirror image of normal• Interruption of embryonic left arch distal to ductus arteriosus.

Almost always ass. with congenital intracardiac disease– Conotruncal anomalies – TOF, TA, TGA, DORV, LTGA, PA with RV aorta– Other lesions – VSD, PA with IVS

Ductus is commonly L sided - attached to L innom. A. – no vascular ring

Echo/Angio -Distinctive branching pattern

CxR/ Ba oesophagography -R indentation of trachea/oesophagus• Treatment

RAA only - No Rx needed

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Type II vascular rings (right aortic arch with retroesophageal ligamentum arteriosum)

account for 45% of complete vascular rings.

The majority of these defects have left descending aortas.

A remnant or stump of the left fourth arch (Kommerell's diverticulum) may persist.

The left subclavian artery arises aberrantly behind the esophagus from the right-sided arch or from Kommerell's diverticulum.

Near this point the left-sided ligamentum emanates and joins the left pulmonary artery to create a complete ring about the trachea and esophagus.

Mirror-image branching and

retroesophageal ligamentum arteriosum.

Interruption of the left arch is proximal (upstream) to the ductus arteriosus

The left-sided ligamentum arteriosum extends from a diverticulum (Kommerell) on the upper descending thoracic aorta, behind the esophagus, forward to the left pulmonary artery.

The vascular ring is formed by the ascending portion of the right arch and innominate artery anteriorly, by the aortic diverticulum posteriorly, and by the ligamentum arteriosum laterally.

This anomaly is rare.

KOMMERELL’s Diverticulum

identification of a Kommerell's diverticulum as part of the pathology.

Remnant of the left fourth aortic arch that did not undergo complete involution.

The diverticulum may independently compress the esophagus or trachea.

Complications of ruptured aneurysm and aortic dissection.

This aneurysmal dilatation should be resected if present and usually necessitates transfer of the left subclavian artery to the left carotid artery

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Representative 3D CTA showing Kommerell’s diverticulum and aberrant left subclavian artery

Sagittal view showing compression of the trachea by the arch and aberrant subclavian artery

TYPE III

Type III-Retroesophageal left subclavian artery and ligamentum (ductus) arteriosum.

Most common type of vascular ring associated with right arch.

Interruption of the left arch occurs between the left subclavian and left common carotid arteries .

The first branch of the right arch becomes the left common carotid artery, and the descending aorta gives origin to the left subclavian artery as the fourth branch.

It is usually loose, so compression of either the esophagus or trachea is uncommon.

Associated cardiac anomalies are rare.

Type IV-Retroesophageal left innominate artery

Here interruption occurs between the left common carotid and the right arch

A vascular ring is present, but the anomaly is rare.

Surgical approachThe surgical approach is through a left thoracotomy.

After careful dissection and identification of the configuration of the aortic arch, the ligamentum arteriosum is identified as compressing the esophagus.

The ring is released by dividing the ligamentum between vascular clamps and oversewing the stumps with Prolene suture.

Any adhesive bands around the esophagus are lysed.

SURGICAL REPORT11 children required additional surgery because their vascular ring (ligamentum) was divided without addressing the associated Kommerell's diverticulum.

All were symptomatic, with recurrent respiratory symptoms or recurrent dysphagia.

All patients responded to reoperation with resection of the diverticulum and transfer of the left subclavian artery to the left carotid artery with resolution of airway symptoms

The primary strategy for patients with a right aortic arch, left ligamentum, and Kommerell's diverticulum –

division of the ligamentum,

resection of Kommerell's diverticulum,

left subclavian artery transfer

CIRCUMFLEX AORTA

RAA + LEFT LIGAMENTUM ARTERIOSUM + LEFT DESCENDING THORACIC AORTA

UNCROSSING OPERATION

Median sternotomy+ CPB+ HCA

Aortic arch mobilized + divided infront of tracheobronchial tree+ reanastomosed end to side to the lateral aspect of ascending aorta.

LEFT AORTIC ARCHVascular rings are likely in the uncommon combination of aortic arch and right descending aorta.

The left arch crosses behind the esophagus.

In combination with right patent ductus arteriosus or ligamentum arteriosum, a vascuLAR RING IS FORMED.

CERVICAL AORTIC ARCHCervical aortic arch is a developmental entity consisting of persistence of the right or left third branchial arch and regression of the fourth branchial arch.

The aorta is usually redundant and crosses to the opposite side posterior to the esophagus.

A vascular ring is formed when there is an aberrant subclavian artery on the side of the aortic arch and a ligamentum arteriosum.

Abnormalities of brachiocephalic arterial branching and arch laterality are common in patients with cervical aortic arch.

Vascular ring is frequently present, usually formed by the right aortic arch and aberrant left subclavian artery, but occasionally by double aortic arch.

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2.1 L AA with retroesophageal R SCA

Most common arch anomaly – 0.5% population

Higher incidence in Downs with CHD – 38%

Mostly asymptomatic

– Ba oesophagograph -Small filling defect slanting up and R

Innominate artery compression Syndrome Anterior compression of the trachea by the innominate artery.

There is a “normal” left aortic arch- innominate artery originate more posteriorly and leftward on the aortic arch than usual.

The artery then courses to the right, upward, and posterior to reach the thoracic outlet, it compresses the trachea anteriorly.

Infants present with stridor, respiratory distress, cyanosis, and apnea with feeding.

The infant may hold its head hyperextended to splint the trachea and improve breathing.

Rigid bronchoscopy -demonstrate a pulsatile anterior compression of the trachea

Anterior compression of the tracheal wall by the bronchoscope may compress the innominate artery and temporarily obliterate the right radial pulse.

The diagnosis can be confirmed by CT scan, which will demonstrate flattening and obliteration of the tracheal lumen by the contrast-filled innominate

PULMONARY ARTERY SLINGA pulmonary artery sling is a rare vascular anomaly in which the left pulmonary artery originates from the right pulmonary artery and encircles the right mainstem bronchus and distal trachea before coursing anterior to the esophagus and descending aorta to enter the hilum of the left lung

First reported by Glaevecke and Doehle.

Cosentino and associates- “ring-sling” complex.

Nearly all infants present within the first months of life with respiratory distress, particularly if there are associated complete tracheal rings.

complete tracheal rings were found in 58% of patients with pulmonary artery sling.

A chest radiograph may show unilateral hyperaeration of the right lung field.

A barium esophagogram shows anterior compression of the esophagus on the lateral views.

Both CT and MRI will show the left pulmonary artery originating from the right pulmonary artery, encircling the trachea, and coursing to the hilum of the left lung .

Echocardiography is- diagnostic procedure of choice for pulmonary artery sling for the patient with an unstable airway.

Bronchoscopy should be performed in all these infants to check for associated complete tracheal rings.

SURGICAL APPROACHSurgical intervention should be undertaken as soon as the diagnosis is made because of the usual tenuous respiratory status.

The first successful operation -by Potts and coworkers69 at Children's Memorial Hospital through a right thoracotomy.

Present approach with median sternotomy and the use of extracorporeal circulation.

This allows accurate division of the left pulmonary artery with implantation into the main pulmonary artery anterior to the trachea

Over 50% will have associated complete tracheal rings (the ring-sling complex), the median sternotomy approach allows simultaneous tracheoplasty.

VATSVideo-assisted thoracoscopic surgery (VATS) has been successfully applied to some patients with complete vascular rings.

The most suitable patients are those with a right aortic arch with aberrant left subclavian artery and left ligamentum arteriosum (type IB) and the occasional patient with a double aortic arch with an atretic left arch.

In these patients a nonvascular segment of the ring can be approached endoscopically and safely divided.

MRI can accurately detect segmental patency or atresia and thereby identify those vascular ring patients suitable for the VATS approach.

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