Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
Current Problems in Diagnostic Radiology journal homepage: www.cpdrjournal.com
Cardiovascular Causes of Pediatric Airway Compression: A Pictorial Review☆ Manphool Singhal, MD, DNBa, Pankaj Gupta, MD, DNBa,n, Rana Sandip Singh, MS, MChb, Manoj Kumar Rohit, MD, DMc, Kushaljit Singh Sodhi, MDa, Niranjan Khandelwal, MD, DNBa a
Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India Department of Cardiothoracic Surgery, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India c Department of Cardiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India b
Airways compression by vascular structures is one of the important comorbidities of congenital heart disease with incidence of approximately 1%-2% in children. Airways compression is a consequence of abnormal configuration of the great vessels producing a vascular ring with enlargement of normal structures (pulmonary arteries or cardiac chambers) or because of surgery. A high index of suspicion for vascular airway compression is important in children with recurrent respiratory complaints. Early diagnosis and management are essential, as chronic airway compression causes significant morbidity. As the underlying anatomical patterns tend to be highly complex, presurgical imaging assessment is essential. & 2015 Elsevier Inc. All rights reserved.
Introduction Vascular rings are the most common congenital anomalies that are associated with airway compression.1 These vascular structures encasing the airways either can be patent or may be replaced with atretric fibrous tissue or ligamentum arteriosum (eg, right-sided aortic arch with aberrant left subclavian artery [ALSA]).1
Embryologic Basis The major vascular system consisting of aortic arch with its branches and pulmonary arteries develop from the branchial arches.1 Aberration in the normal development during the course of this complex embryologic process results in malformations that lead to vascular airway compression. With the current multidetector computed tomography (CT) technology, CT has evolved as an important tool in the evaluation of pediatric cardiovascular and airway abnormalities.2 Advantages over magnetic resonance imaging include (1) reduced scan time and improved spatial resolution; (2) multiplanar reconstruction and minimal-intensity projections, which allow the evaluation of the airway and the site of compression with greater accuracy; and (3) 3-dimensional volume rendered images and virtual bronchoscopic evaluation, which allow a good endoluminal evaluation. However, virtual bronchoscopy is not a substitute to the bronchoscopy. ☆ Authors had full control of all primary data, and we agree to allow the Journal to review our data if requested. n Reprint requests: Pankaj Gupta, Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh, India. E-mail address: [email protected] (P. Gupta).
http://dx.doi.org/10.1067/j.cpradiol.2015.04.005 0363-0188/& 2015 Elsevier Inc. All rights reserved.
The main disadvantage of CT is the ionizing nature of the radiations involved. Thus, attempts are made to modify protocols to reduce the radiation dose. The latter is achieved by using either weight-based protocols or tube current modulation techniques. In general, surgical correction involves transection of the underlying ring or sling components. Additional techniques include anterior aortic arch translocation, resection-reimplantation of left pulmonary artery, segmental tracheal resection, external tracheal or bronchial suspension, aortic extension by a prosthetic tube, and transection of the ligamentum arteriosum. Left thoracotomy is the most common surgical approach. Median sternotomy may be required in certain conditions. In a large single-center experience in surgical management of aortic arch anomalies causing tracheoesophageal compression, Ruzmetov et al used a left thoracotomy approach for all the conditions except pulmonary sling, where they resorted to median sternotomy. We discuss some of the common and uncommon vascular causes of airway compression.
Congenital Causes Arch Anomalies Double Aortic Arch It is the commonest vascular cause of airway compression in pediatric age. It has an incidence of 3% at autopsy, though it is rarely symptomatic.3 This anomaly is characterized by the presence of 2 separate aortic arches on the left and right sides, arising from the ascending aorta that encases both the trachea and the esophagus. Double aortic arch (DAA) is most commonly right
2
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
Fig. 2. A 5-year-old boy with right aortic arch (RAA) with aberrant left subclavian artery (ALSA). An axial CTA image shows RAA (arrow) with ALSA (short arrow) causing mild extrinsic impression on the trachea. CTA, CT angiography. (Color version of figure is available online.)
incidentally. In 90% of right-sided aortic arches (RAAs) with ALSAs, there is a left ductus arteriosus.6 An RAA with ALSA and Kommerell diverticulum (an out pouching of the descending aorta from where ALSA originates) is the second most common cause of a symptomatic vascular ring, accounting for 30% of cases (Fig 2).7 Several factors may contribute to airway compression: enlargement of Kommerell diverticulum, a midline descending aorta, or a tight ligamentum arteriosum. Surgical correction comprises transection of the ligamentum arteriosum and the diverticulum, as the latter may result in compression of the esophagus or the trachea or both, particularly as the child grows.
Left-Sided Aortic Arch With Aberrant Right Subclavian Artery Though left-sided aortic arch with aberrant right subclavian artery is the commonest aortic arch anomaly having an incidence of 0.5%-2%, it rarely leads to airway compression (Fig 3).3 This situation arises in the setting of a right-sided ligamentum arteriosum.
Fig. 1. A 3-year-old boy with double aortic arch. Axial (A) and VR CTA (B) images show double aortic arch (arrows) encircling the trachea with external compression. CTA, CT angiography; VR, volume rendered. (Color version of figure is available online.)
dominant. The right arch courses posteriorly and to the left behind the esophagus. The left arch usually has an anterior course. DAA represents the most common complete vascular ring (Fig 1). The tightness of the ring determines the onset and severity of symptoms. Surgical correction involves transection of the nondominant arch. It has been reported that up to 30% of children may have persistent respiratory symptoms after surgical correction, the cause of which is postulated to malacia of lower trachea owing to severe and prolonged compression that in most cases is selflimiting.4 Right-Sided Aortic Arch With ALSA This anomaly has an incidence of 0.05%.5 Like DAA, most patients are asymptomatic and detected to have the anomaly
Fig. 3. A 3-year-old boy with left-sided aortic arch (LAA) with aberrant right subclavian artery (ARSA). An axial CTA image shows LAA (arrow) with ARSA (short arrow) causing extrinsic impression on the trachea. CTA, CT angiography. (Color version of figure is available online.)
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
3
artery), and type C (between the left carotid artery and the brachiocephalic artery).8 Airway compression can be associated with the anomaly per se (Fig 5) or following surgical correction (Fig 6). End-to-end anastomosis is performed between the ascending and the descending aortas, irrespective of the type of IAA. Surgical correction typically leads to anterior displacement of the descending aorta (owing to the shortening of the aortic arch) and extrinsic compression of the left main bronchus between the left pulmonary artery and the aorta.9 Management of postsurgical airway compression is challenging. It is usually managed with airway stenting.
Fig. 4. A 6-year-old girl with coarctation of aorta. An oblique VR image (A) shows postductal coarctation (arrow). An axial MIP image (B) shows extrinsic compression of the right main bronchus between the right pulmonary artery (arrows) and the descending thoracic aorta (short arrow). LPA, left pulmonary artery; MIP, maximum intensity projection, MPA, main pulmonary artery; RPA, right pulmonary artery; VR, volume rendered. (Color version of figure is available online.)
Coarctation of Aorta Airway compression in the setting of coarctation of aorta results from abnormal aortopulmonary space geometry (Fig 4).
Interrupted Aortic Arch Interrupted aortic arch (IAA) is a distinctly uncommon congenital anomaly. It is characterized by loss of continuity between the ascending and the descending aortas.8 IAA differs from severe coarctation in complete loss of connection between the ascending and the descending aortas. Based on the site of interruption, 3 subtypes are known: type A (distal to the left subclavian artery), type B (between the left subclavian artery and the left carotid
Fig. 5. A 1-year-old boy with interrupted aortic arch. An axial CTA image (A) in a patient with interrupted aortic arch shows marked dilatation of the main pulmonary artery with compression of the left main bronchus (arrow). A VR image (B) demonstrated the lack of connection between the arch of aorta and the descending thoracic aorta (arrow). CTA, CT angiography; VR, volume rendered. (Color version of figure is available online.)
4
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
Fig. 9. A 7-year-old boy with pulmonary artery aneurysm secondary to Marfan syndrome. An axial CTA image shows aneurysmal dilatation of bilateral pulmonary arteries (asterisk) with marked extrinsic compression of right and left main bronchi (short arrows) with almost complete collapse of the left lung (arrows). CTA, CT angiography.
Fig. 6. Surgically corrected (end-to-end anastomosis of arch and descending aorta) interrupted aortic arch in a 1-year-old boy. A sagittal reformatted CTA image in a patient who underwent corrective surgery for interrupted aortic arch shows compression of the left bronchus (thick arrow) between the descending thoracic aorta (arrow) and the left pulmonary artery (short arrow). CTA, CT angiography.
Fig. 7. An 8-month-old girl with pulmonary sling. An axial CTA image show left pulmonary artery coursing behind the trachea (pulmonary artery sling, arrow) causing extraneous compression on trachea (short arrow). CTA, CT angiography.
Fig. 8. A 2-year-old boy with absent pulmonary valve syndrome. An axial CTA image shows of dilatation of right and left pulmonary arteries (arrows) resulting in external compression of left main bronchus. CTA, CT angiography.
Fig. 10. A 1-year-old girl with tetralogy of Fallot. An axial CTA image (A) shows dilatation of the aortic arch (arrowhead) in a patient with tetralogy of Fallot with compression of the trachea (arrows). An air-filled dilated esophagus (short arrow) can also be noted. A coronal minIP image (B) shows extrinsic compression of the trachea and the left main bronchus (arrow). CTA, CT angiography, minIP, minimalintensity projection. (Color version of figure is available online.)
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
5
Cervical (High) Aortic Arch This is an extremely rare cause of airway compromise. Management involves reconstruction of the cervical arch, with adjustment to an intrathoracic position. Two extremely rare causes of vascular rings include left aortic arch with right descending aorta and right ductus and right aortic arch with left descending aorta and left ductus. Pulmonary Arterial Abnormalities Pulmonary Artery Sling Pulmonary sling refers to left pulmonary artery arising from the posterior aspect of the right pulmonary artery (Fig 7). This leads to an anomalous course of left pulmonary artery that passes between the lower trachea and the esophagus, causing airway compression. An important and clinically significant association is long-segment congenital tracheal stenosis with complete tracheal cartilage rings. This abnormality is noted in more than
Fig. 11. A 5-year-old boy with tetralogy of Fallot and major aortopulmonary channel (MAPCA). An axial CTA image (A) in a patient with tetralogy of Fallot shows markedly dilated MAPCA causing compression of the right main bronchus (cursors). A VR image (B) better depicts the MAPCA (arrow). CTA, CT angiography; VR, volume rendered. (Color version of figure is available online.)
Fig. 12. An 18-month-old boy with congenital aneurysmal dilatation of patent ductus arteriosus (PDA). An axial CTA image show aneurysmal dilatation of PDA (asterisk) with compression of the left main bronchus (arrowhead). The relationship of PDA with the descending aorta (short arrow) and the left pulmonary artery (arrow) can be noted. CTA, CT angiography.
Fig. 13. A 2-year-old girl with transposition of great arteries (TGA). A VR image (A) and coronal minIP image (B) show dilated PDA (arrow, A) in patient with TGA causing compression of the left main bronchus (arrow, B). minIP, minimal-intensity projection; VR, volume rendered. (Color version of figure is available online.)
6
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
50% patients with pulmonary artery sling.11 The treatment of choice for long-segment congenital tracheal stenosis is slide tracheoplasty.11
Absent Pulmonary Valve Syndrome Absent pulmonary valve syndrome (APVS) is characterized by the presence of hypoplastic pulmonary valve cusps and dilated pulmonary arteries. It is usually seen in association with a ventricular septal defect (causing dilatation of left-sided chambers) and right ventricular outflow tract obstruction. APVS occurs in 3%-6% of patients with tetralogy of Fallot, but it can also be seen in isolation. The compression of the lower trachea and the bilateral main bronchi results from enlargement of the pulmonary arteries and the left atrium (Fig 8).10 Surgical repair usually involves replacement of the pulmonary artery with conduits or reduction arterioplasty. Additionally, LeCompte maneuver wherein the aorta is transected, allowing the pulmonary arteries to lie anterior to the reconstructed aorta, is beneficial. Stenting of the airway is usually avoided owing to the risk of erosion of the pulmonary artery.
Pulmonary Artery Aneurysm It can arise in the setting of structural cardiac anomalies (including left to right shunts and Eisenmenger complex), connective tissue disorders (including Marfan syndrome, EhlersDanlos syndrome, and cystic medial necrosis), pulmonary artery hypertension, vasculitis, infections, and iatrogenic conditions (malpositioned Swan-Ganz catheters, chest tube insertion, conventional angiography, and surgical resection or biopsy).12-14 A massively dilated pulmonary artery can cause compression of the airway at various levels (Fig 9).
Intracardiac Defects Patients with intracardiac defects may have abnormal aortopulmonary space geometry. This may lead to airway compression between various vascular structures (Figs 10 and 11).
Abnormalities of the Ductus Arteriosus Airway compression may result from aneurysmal dilatation of ductus arteriosus (Fig 12) or dilated ductus arteriosus (Fig 13) in the setting of shunts.
Conclusion Vascular causes of airway compression are uncommon, yet, they are important causes of morbidity in children with congenital heart disease. CT angiography allows comprehensive evaluation of the complex structural anomalies and airway, facilitating the timely management. References 1. McLaren CA, Elliott MJ, Roebuck DJ. Vascular compression of the airway in children. Pediatr Respir Rev 2008;9:85–94. 2. Papaioannou G, Young C, Owens CM. Multidetector row CT for imaging the paediatric tracheobronchial tree. Pediatr Radiol 2007;37:515–29. 3. McLaughlin RB Jr, Wetmore RF, Tavill MA, et al. Vascular anomalies causing symptomatic tracheobronchial compression. Laryngoscope 1999;109:312–9. 4. Fleck RJ, Pacharn P, Fricke BL, et al. Imaging findings in pediatric patients with persistent airway symptoms after surgery for double aortic arch. Am J Roentgenol 2002;178:1275–9. 5. Schlesinger AE, Krishnamurthy R, Sena LM, et al. Incomplete double aortic arch with atresia of the distal left arch: Distinctive imaging appearance. Am J Roentgenol 2005;184:1634–9. 6. Stewart JR, Kincaid OW, Titus J. Right aortic arch: Plain film diagnosis and significance. Am J Roentgenol Radium Ther Nucl Med 1966;9:377–89. 7. Park SC. Symposium on pediatric otolaryngology. Vascular abnormalities. Pediatrc Clin North Am 1981;28:949–55. 8. Reardon MJ, Hallman GL, Cooley DA. Interrupted aortic arch: Brief review and summary of an eighteen-year experience. Tex Heart Inst J 1984;11:250–9. 9. Schreiber C, Eicken A, Vogt M, et al. Repair of interrupted aortic arch: Results after more than 20 years. Ann Thorac Surg 2000;70:1896–9. 10. Saygili A, Tiker F, Bagis T, et al. Absent pulmonary valves syndrome diagnosed by fetal echocardiography. Turk J Pediatr 2004;46:88–91. 11. Elliott M, Roebuck D, Noctor C, et al. The management of congenital tracheal stenosis. Int J Pediatr Otorhinolaryngol 2003;67:S183–92. 12. Bartter T, Irwin RS, Nash G. Aneurysms of the pulmonary arteries. Chest 1988;94:1065–75. 13. Durieux P, Bletry O, Huchon G, et al. Multiple pulmonary arterial aneurysms in Behçet's disease and Hughes-Stovin syndrome. Am J Med 1981;71:736–41. 14. Boyd KD, Thomas SJ, Gold J, et al. A prospective study of complication of pulmonary artery catheterizations in 500 consecutive patients. Chest 1993;84:243–9.
Current Problems in Diagnostic Radiology journal homepage: www.cpdrjournal.com
Cardiovascular Causes of Pediatric Airway Compression: A Pictorial Review☆ Manphool Singhal, MD, DNBa, Pankaj Gupta, MD, DNBa,n, Rana Sandip Singh, MS, MChb, Manoj Kumar Rohit, MD, DMc, Kushaljit Singh Sodhi, MDa, Niranjan Khandelwal, MD, DNBa a
Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India Department of Cardiothoracic Surgery, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India c Department of Cardiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India b
Airways compression by vascular structures is one of the important comorbidities of congenital heart disease with incidence of approximately 1%-2% in children. Airways compression is a consequence of abnormal configuration of the great vessels producing a vascular ring with enlargement of normal structures (pulmonary arteries or cardiac chambers) or because of surgery. A high index of suspicion for vascular airway compression is important in children with recurrent respiratory complaints. Early diagnosis and management are essential, as chronic airway compression causes significant morbidity. As the underlying anatomical patterns tend to be highly complex, presurgical imaging assessment is essential. & 2015 Elsevier Inc. All rights reserved.
Introduction Vascular rings are the most common congenital anomalies that are associated with airway compression.1 These vascular structures encasing the airways either can be patent or may be replaced with atretric fibrous tissue or ligamentum arteriosum (eg, right-sided aortic arch with aberrant left subclavian artery [ALSA]).1
Embryologic Basis The major vascular system consisting of aortic arch with its branches and pulmonary arteries develop from the branchial arches.1 Aberration in the normal development during the course of this complex embryologic process results in malformations that lead to vascular airway compression. With the current multidetector computed tomography (CT) technology, CT has evolved as an important tool in the evaluation of pediatric cardiovascular and airway abnormalities.2 Advantages over magnetic resonance imaging include (1) reduced scan time and improved spatial resolution; (2) multiplanar reconstruction and minimal-intensity projections, which allow the evaluation of the airway and the site of compression with greater accuracy; and (3) 3-dimensional volume rendered images and virtual bronchoscopic evaluation, which allow a good endoluminal evaluation. However, virtual bronchoscopy is not a substitute to the bronchoscopy. ☆ Authors had full control of all primary data, and we agree to allow the Journal to review our data if requested. n Reprint requests: Pankaj Gupta, Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh, India. E-mail address: [email protected] (P. Gupta).
http://dx.doi.org/10.1067/j.cpradiol.2015.04.005 0363-0188/& 2015 Elsevier Inc. All rights reserved.
The main disadvantage of CT is the ionizing nature of the radiations involved. Thus, attempts are made to modify protocols to reduce the radiation dose. The latter is achieved by using either weight-based protocols or tube current modulation techniques. In general, surgical correction involves transection of the underlying ring or sling components. Additional techniques include anterior aortic arch translocation, resection-reimplantation of left pulmonary artery, segmental tracheal resection, external tracheal or bronchial suspension, aortic extension by a prosthetic tube, and transection of the ligamentum arteriosum. Left thoracotomy is the most common surgical approach. Median sternotomy may be required in certain conditions. In a large single-center experience in surgical management of aortic arch anomalies causing tracheoesophageal compression, Ruzmetov et al used a left thoracotomy approach for all the conditions except pulmonary sling, where they resorted to median sternotomy. We discuss some of the common and uncommon vascular causes of airway compression.
Congenital Causes Arch Anomalies Double Aortic Arch It is the commonest vascular cause of airway compression in pediatric age. It has an incidence of 3% at autopsy, though it is rarely symptomatic.3 This anomaly is characterized by the presence of 2 separate aortic arches on the left and right sides, arising from the ascending aorta that encases both the trachea and the esophagus. Double aortic arch (DAA) is most commonly right
2
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
Fig. 2. A 5-year-old boy with right aortic arch (RAA) with aberrant left subclavian artery (ALSA). An axial CTA image shows RAA (arrow) with ALSA (short arrow) causing mild extrinsic impression on the trachea. CTA, CT angiography. (Color version of figure is available online.)
incidentally. In 90% of right-sided aortic arches (RAAs) with ALSAs, there is a left ductus arteriosus.6 An RAA with ALSA and Kommerell diverticulum (an out pouching of the descending aorta from where ALSA originates) is the second most common cause of a symptomatic vascular ring, accounting for 30% of cases (Fig 2).7 Several factors may contribute to airway compression: enlargement of Kommerell diverticulum, a midline descending aorta, or a tight ligamentum arteriosum. Surgical correction comprises transection of the ligamentum arteriosum and the diverticulum, as the latter may result in compression of the esophagus or the trachea or both, particularly as the child grows.
Left-Sided Aortic Arch With Aberrant Right Subclavian Artery Though left-sided aortic arch with aberrant right subclavian artery is the commonest aortic arch anomaly having an incidence of 0.5%-2%, it rarely leads to airway compression (Fig 3).3 This situation arises in the setting of a right-sided ligamentum arteriosum.
Fig. 1. A 3-year-old boy with double aortic arch. Axial (A) and VR CTA (B) images show double aortic arch (arrows) encircling the trachea with external compression. CTA, CT angiography; VR, volume rendered. (Color version of figure is available online.)
dominant. The right arch courses posteriorly and to the left behind the esophagus. The left arch usually has an anterior course. DAA represents the most common complete vascular ring (Fig 1). The tightness of the ring determines the onset and severity of symptoms. Surgical correction involves transection of the nondominant arch. It has been reported that up to 30% of children may have persistent respiratory symptoms after surgical correction, the cause of which is postulated to malacia of lower trachea owing to severe and prolonged compression that in most cases is selflimiting.4 Right-Sided Aortic Arch With ALSA This anomaly has an incidence of 0.05%.5 Like DAA, most patients are asymptomatic and detected to have the anomaly
Fig. 3. A 3-year-old boy with left-sided aortic arch (LAA) with aberrant right subclavian artery (ARSA). An axial CTA image shows LAA (arrow) with ARSA (short arrow) causing extrinsic impression on the trachea. CTA, CT angiography. (Color version of figure is available online.)
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
3
artery), and type C (between the left carotid artery and the brachiocephalic artery).8 Airway compression can be associated with the anomaly per se (Fig 5) or following surgical correction (Fig 6). End-to-end anastomosis is performed between the ascending and the descending aortas, irrespective of the type of IAA. Surgical correction typically leads to anterior displacement of the descending aorta (owing to the shortening of the aortic arch) and extrinsic compression of the left main bronchus between the left pulmonary artery and the aorta.9 Management of postsurgical airway compression is challenging. It is usually managed with airway stenting.
Fig. 4. A 6-year-old girl with coarctation of aorta. An oblique VR image (A) shows postductal coarctation (arrow). An axial MIP image (B) shows extrinsic compression of the right main bronchus between the right pulmonary artery (arrows) and the descending thoracic aorta (short arrow). LPA, left pulmonary artery; MIP, maximum intensity projection, MPA, main pulmonary artery; RPA, right pulmonary artery; VR, volume rendered. (Color version of figure is available online.)
Coarctation of Aorta Airway compression in the setting of coarctation of aorta results from abnormal aortopulmonary space geometry (Fig 4).
Interrupted Aortic Arch Interrupted aortic arch (IAA) is a distinctly uncommon congenital anomaly. It is characterized by loss of continuity between the ascending and the descending aortas.8 IAA differs from severe coarctation in complete loss of connection between the ascending and the descending aortas. Based on the site of interruption, 3 subtypes are known: type A (distal to the left subclavian artery), type B (between the left subclavian artery and the left carotid
Fig. 5. A 1-year-old boy with interrupted aortic arch. An axial CTA image (A) in a patient with interrupted aortic arch shows marked dilatation of the main pulmonary artery with compression of the left main bronchus (arrow). A VR image (B) demonstrated the lack of connection between the arch of aorta and the descending thoracic aorta (arrow). CTA, CT angiography; VR, volume rendered. (Color version of figure is available online.)
4
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
Fig. 9. A 7-year-old boy with pulmonary artery aneurysm secondary to Marfan syndrome. An axial CTA image shows aneurysmal dilatation of bilateral pulmonary arteries (asterisk) with marked extrinsic compression of right and left main bronchi (short arrows) with almost complete collapse of the left lung (arrows). CTA, CT angiography.
Fig. 6. Surgically corrected (end-to-end anastomosis of arch and descending aorta) interrupted aortic arch in a 1-year-old boy. A sagittal reformatted CTA image in a patient who underwent corrective surgery for interrupted aortic arch shows compression of the left bronchus (thick arrow) between the descending thoracic aorta (arrow) and the left pulmonary artery (short arrow). CTA, CT angiography.
Fig. 7. An 8-month-old girl with pulmonary sling. An axial CTA image show left pulmonary artery coursing behind the trachea (pulmonary artery sling, arrow) causing extraneous compression on trachea (short arrow). CTA, CT angiography.
Fig. 8. A 2-year-old boy with absent pulmonary valve syndrome. An axial CTA image shows of dilatation of right and left pulmonary arteries (arrows) resulting in external compression of left main bronchus. CTA, CT angiography.
Fig. 10. A 1-year-old girl with tetralogy of Fallot. An axial CTA image (A) shows dilatation of the aortic arch (arrowhead) in a patient with tetralogy of Fallot with compression of the trachea (arrows). An air-filled dilated esophagus (short arrow) can also be noted. A coronal minIP image (B) shows extrinsic compression of the trachea and the left main bronchus (arrow). CTA, CT angiography, minIP, minimalintensity projection. (Color version of figure is available online.)
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
5
Cervical (High) Aortic Arch This is an extremely rare cause of airway compromise. Management involves reconstruction of the cervical arch, with adjustment to an intrathoracic position. Two extremely rare causes of vascular rings include left aortic arch with right descending aorta and right ductus and right aortic arch with left descending aorta and left ductus. Pulmonary Arterial Abnormalities Pulmonary Artery Sling Pulmonary sling refers to left pulmonary artery arising from the posterior aspect of the right pulmonary artery (Fig 7). This leads to an anomalous course of left pulmonary artery that passes between the lower trachea and the esophagus, causing airway compression. An important and clinically significant association is long-segment congenital tracheal stenosis with complete tracheal cartilage rings. This abnormality is noted in more than
Fig. 11. A 5-year-old boy with tetralogy of Fallot and major aortopulmonary channel (MAPCA). An axial CTA image (A) in a patient with tetralogy of Fallot shows markedly dilated MAPCA causing compression of the right main bronchus (cursors). A VR image (B) better depicts the MAPCA (arrow). CTA, CT angiography; VR, volume rendered. (Color version of figure is available online.)
Fig. 12. An 18-month-old boy with congenital aneurysmal dilatation of patent ductus arteriosus (PDA). An axial CTA image show aneurysmal dilatation of PDA (asterisk) with compression of the left main bronchus (arrowhead). The relationship of PDA with the descending aorta (short arrow) and the left pulmonary artery (arrow) can be noted. CTA, CT angiography.
Fig. 13. A 2-year-old girl with transposition of great arteries (TGA). A VR image (A) and coronal minIP image (B) show dilated PDA (arrow, A) in patient with TGA causing compression of the left main bronchus (arrow, B). minIP, minimal-intensity projection; VR, volume rendered. (Color version of figure is available online.)
6
M. Singhal et al. / Current Problems in Diagnostic Radiology ] (2015) ]]]–]]]
50% patients with pulmonary artery sling.11 The treatment of choice for long-segment congenital tracheal stenosis is slide tracheoplasty.11
Absent Pulmonary Valve Syndrome Absent pulmonary valve syndrome (APVS) is characterized by the presence of hypoplastic pulmonary valve cusps and dilated pulmonary arteries. It is usually seen in association with a ventricular septal defect (causing dilatation of left-sided chambers) and right ventricular outflow tract obstruction. APVS occurs in 3%-6% of patients with tetralogy of Fallot, but it can also be seen in isolation. The compression of the lower trachea and the bilateral main bronchi results from enlargement of the pulmonary arteries and the left atrium (Fig 8).10 Surgical repair usually involves replacement of the pulmonary artery with conduits or reduction arterioplasty. Additionally, LeCompte maneuver wherein the aorta is transected, allowing the pulmonary arteries to lie anterior to the reconstructed aorta, is beneficial. Stenting of the airway is usually avoided owing to the risk of erosion of the pulmonary artery.
Pulmonary Artery Aneurysm It can arise in the setting of structural cardiac anomalies (including left to right shunts and Eisenmenger complex), connective tissue disorders (including Marfan syndrome, EhlersDanlos syndrome, and cystic medial necrosis), pulmonary artery hypertension, vasculitis, infections, and iatrogenic conditions (malpositioned Swan-Ganz catheters, chest tube insertion, conventional angiography, and surgical resection or biopsy).12-14 A massively dilated pulmonary artery can cause compression of the airway at various levels (Fig 9).
Intracardiac Defects Patients with intracardiac defects may have abnormal aortopulmonary space geometry. This may lead to airway compression between various vascular structures (Figs 10 and 11).
Abnormalities of the Ductus Arteriosus Airway compression may result from aneurysmal dilatation of ductus arteriosus (Fig 12) or dilated ductus arteriosus (Fig 13) in the setting of shunts.
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