Vascular Rings

Overview

Definition

A vascular ring Vascular Ring Pediatric Chest Abnormalities is a congenital Congenital Chorioretinitis malformation in which the esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy and trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy are encircled by an aberrant aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy.

Embryology

• 4th–5th week of gestation: Mesenchymal cells migrate from the neural crest Neural crest The two longitudinal ridges along the primitive streak appearing near the end of gastrulation during development of nervous system (neurulation). The ridges are formed by folding of neural plate. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the neural tube. Hirschsprung Disease and paraxial mesoderm Mesoderm The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube. Gastrulation and Neurulation → proliferate and form 4 bulges located above heart and liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy → branchial arches Branchial arches The branchial arches, also known as pharyngeal or visceral arches, are embryonic structures seen in the development of vertebrates that serve as precursors for many structures of the face, neck, and head. These arches are composed of a central core of mesoderm, which is covered externally by ectoderm and internally by endoderm. Branchial Apparatus and Aortic Arches I–VI
• Each branchial arch has its own artery originating in the aortic root and leading to 2 paired dorsal aortae, which merge caudally into the descending aorta Descending aorta Mediastinum and Great Vessels: Anatomy.
• 1st and 2nd aortic arches:
  • Mostly degenerate
  • 1st arch → maxillary artery
  • 2nd arch → stapedial artery
• 3rd aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy:
  • Proximal sections → common carotid artery Common carotid artery The two principal arteries supplying the structures of the head and neck. They ascend in the neck, one on each side, and at the level of the upper border of the thyroid cartilage, each divides into two branches, the external and internal carotid arteries. Carotid Arterial System: Anatomy
  • Distal sections → internal carotid artery Internal carotid artery Branch of the common carotid artery which supplies the anterior part of the brain, the eye and its appendages, the forehead and nose. Carotid Arterial System: Anatomy together with parts of dorsal aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
• 4th aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy:
  • Left → defined aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy
  • Right → proximal section of right subclavian artery
• 5th aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy doesn’t develop.
• 6th aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy = pulmonary arch
  • Left → ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) 
  • Right → truncus pulmonalis and proximal part of pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy
  • By the time the 6th arch develops, the 1st and 2nd arches have already disappeared.

Anatomy

Although the clinical symptoms and treatment approach are the same, there are multiple ways in which the development of the aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy can give rise to a vascular ring Vascular Ring Pediatric Chest Abnormalities. Each variant is unique in its anatomy and embryological origin.

• Double aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy (DAA)
  • Failure of right-sided arch to regress while left-sided arch persists
  • Right-sided arch passes posteriorly to esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy, where it joins left-sided aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy.
  • Left-sided aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy passes anterior to trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy.
  • Result: ring of blood vessels around trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy and esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy
• Right aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy with aberrant left subclavian artery and left-sided ductus/ligamentum arteriosus
  • Aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy is right-sided.
  • Ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) (DA) arises from the base of the aberrant left subclavian artery.
  • DA connects to pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy  by tracking anteriorly and to the left of the trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy and esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy.
  • The right-sided aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy, the left subclavian artery, and the aberrant ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) form the vascular ring Vascular Ring Pediatric Chest Abnormalities around the esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy and trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy.

Epidemiology

• 1%–3% of all congenital Congenital Chorioretinitis cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) malformations
• Male:female ratio, 2:1
• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency of various forms:
  • 55% attributable to DAA
  • 35% attributable to right aortic arches, aberrant left subclavian artery, and left-sided ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA)
  • 10% all other forms
• 10%–25% of cases are associated with underlying cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) anomaly:
  • Transposition of great vessels (TGV)
  • Ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot (VSD)
  • Patent ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) ( PDA PDA The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA))
  • Tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot is the most common cyanotic congenital heart disease. The disease is the confluence of 4 pathologic cardiac features: overriding aorta, ventricular septal defect, right ventricular outflow obstruction, and right ventricular hypertrophy. Tetralogy of Fallot (TOF)
  • Coarctation of aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy (CoA)
• Associated with:
  • Trisomy 21 Trisomy 21 Down syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of developmental delay. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems. Down syndrome (Trisomy 21) (Down’s syndrome)
  • DiGeorge syndrome DiGeorge syndrome DiGeorge syndrome (DGS) is a condition caused by a microdeletion at location q11.2 of chromosome 22 (thus also called 22q11.2 syndrome). There is a defective development of the third and fourth pharyngeal pouches, leading to thymic and parathyroid hypoplasia (causing T-cell immunodeficiency and hypocalcemia, respectively). DiGeorge Syndrome
  • CHARGE syndrome CHARGE Syndrome CHARGE syndrome is a rare genetic condition with autosomal dominant inheritance in which almost all body systems are affected. The acronym CHARGE stands for the constellation of clinical features seen with this condition: Coloboma, Heart defects, Atresia choanae, Growth retardation, Genetic Abnormalities, and Ear abnormalities. CHARGE Syndrome (Coloboma of the eye, Heart defects, Atresia of the nasal choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and E ar AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation abnormalities and deafness)
• Increased risk in infants conceived by in vitro fertilization In vitro fertilization An assisted reproductive technique that includes the direct handling and manipulation of oocytes and sperm to achieve fertilization in vitro. Infertility ( IVF IVF An assisted reproductive technique that includes the direct handling and manipulation of oocytes and sperm to achieve fertilization in vitro. Infertility)

Pathophysiology and Clinical Presentation

Pathophysiology

• Vascular ring Vascular Ring Pediatric Chest Abnormalities encircles trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy and esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy.
• Direct pressure of blood vessels on trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy and esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy can be sufficient to cause symptoms.
• Activities that increase cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) demand (e.g., feeding, crying) cause engorgement Engorgement Mastitis of blood vessels and worsen symptoms.

Clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor

The severity of symptoms depends on the degree of compression Compression Blunt Chest Trauma of the trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy/ esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy.

• Severe compression Compression Blunt Chest Trauma: noisy breathing or apnea within first few weeks of life
• Mild compression Compression Blunt Chest Trauma:
  • Persistent cough
  • Recurrent lung infection Lung infection Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia
  • Vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
  • Choking
  • Difficulty swallowing Swallowing The act of taking solids and liquids into the gastrointestinal tract through the mouth and throat. Gastrointestinal Motility
• May also be picked up incidentally when scanning for other associated cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) anomalies

Diagnosis and Management

Physical examination

Examination may be normal, but usually in infants:

• Nonpositional stridor Stridor Laryngomalacia and Tracheomalacia (classic finding)
• Inspiratory stridor Stridor Laryngomalacia and Tracheomalacia
• Bronchial breath sounds
• Crackles
• Respiratory distress
• Failure to thrive Failure to Thrive Failure to thrive (FTT), or faltering growth, describes suboptimal weight gain and growth in children. The majority of cases are due to inadequate caloric intake; however, genetic, infectious, and oncological etiologies are also common. Failure to Thrive

Imaging

• Echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA): 
  • 1st-line imaging
  • Assesses nature of vascular ring Vascular Ring Pediatric Chest Abnormalities and extent of compression Compression Blunt Chest Trauma
  • Associated cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) anomaly
• Computed tomography (CT) and magnetic resonance imaging (MRI): Best methods to delineate anatomy, location, and extent of compression Compression Blunt Chest Trauma

• Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests:
  • Loss of aortic knob
  • Lateral/posterior indentation of trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy
• Bronchoscopy Bronchoscopy Endoscopic examination, therapy or surgery of the bronchi. Laryngomalacia and Tracheomalacia: Pulsating mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast at level of carina

Management

• Definitive management is surgical therapy, which is indicated for:
  • Symptomatic patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship
  • Concomitant heart defect
• Surgery involves resection and division of vascular ring Vascular Ring Pediatric Chest Abnormalities.
• Reimplantation of key vessels is rarely necessary.
• Excellent prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas post surgery

Differential Diagnosis

• Laryngomalacia Laryngomalacia A congenital or acquired condition of underdeveloped or degeneration of cartilage in the larynx. This results in a floppy laryngeal wall making patency difficult to maintain. Laryngomalacia and Tracheomalacia/ tracheomalacia Tracheomalacia A congenital or acquired condition of underdeveloped or degeneration of cartilage in the trachea. This results in a floppy tracheal wall making patency difficult to maintain. It is characterized by wheezing and difficult breathing. Laryngomalacia and Tracheomalacia: Newborns present with stridor Stridor Laryngomalacia and Tracheomalacia very similar to that of DAA. Stridor Stridor Laryngomalacia and Tracheomalacia is mainly inspiratory. Laryngoscopy confirms collapse of larynx Larynx The larynx, also commonly called the voice box, is a cylindrical space located in the neck at the level of the C3-C6 vertebrae. The major structures forming the framework of the larynx are the thyroid cartilage, cricoid cartilage, and epiglottis. The larynx serves to produce sound (phonation), conducts air to the trachea, and prevents large molecules from reaching the lungs. Larynx: Anatomy.
• Subglottic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS): Congenital Congenital Chorioretinitis forms result in narrowing of subglottic region of trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy, resulting in symptoms very similar to DAA. Laryngoscopy assesses narrowing.
• Bronchiolitis Bronchiolitis Inflammation of the bronchioles. Pediatric Chest Abnormalities: Infants present with lower respiratory symptoms (e.g., dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, wheezing Wheezing Wheezing is an abnormal breath sound characterized by a whistling noise that can be relatively high-pitched and shrill (more common) or coarse. Wheezing is produced by the movement of air through narrowed or compressed small (intrathoracic) airways. Wheezing, and crackles). These infants usually have a history of upper respiratory tract infection and usually respond to supplemental oxygen Supplemental Oxygen Respiratory Failure and suctioning of secretions.
• Gastroesophageal reflux disease Gastroesophageal Reflux Disease Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease (GERD) ( GERD GERD Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease (GERD)): Acid reflux into esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy in infancy and childhood may present with intermittent cough and wheezing Wheezing Wheezing is an abnormal breath sound characterized by a whistling noise that can be relatively high-pitched and shrill (more common) or coarse. Wheezing is produced by the movement of air through narrowed or compressed small (intrathoracic) airways. Wheezing. May be accompanied by lack of weight gain and increased irritability.