Andrew Hromada

David Healey

Manoj Chhabra

Nitin Ron

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Perinatal/Neonatal case presentation: pulmonary artery sling associated with respiratory distress

Healey et al. SpringerPlus  (2016) 5:31 
DOI 10.1186/s40064-015-1656-5
CASE STUDY
Perinatal/Neonatal case presentation: 
pulmonary artery sling associated 
with respiratory distress
David Healey1*, Nitin Ron2,3, Andrew Hromada4,5 and Manoj Chhabra2,3
Abstract 
Pulmonary artery sling is a very rare cause of pediatric respiratory distress. The estimated prevalence of the disease 
was first determined by Yu et al. in 2008 as 59 per million school-aged children. Associated symptoms are cough, 
wheezing, and feeding difficulty, all of which are common in routine outpatient pediatric clinical encounters. We 
report a case of a premature male neonate twin who was admitted to the neonatal intensive care unit with respira-
tory distress and pneumothorax. His presentation, as well as the etiology of his pulmonary disease, was felt to be con-
sistent with those of numerous other premature infants. Akin to this was his delayed discharge on account of his slow 
progress with oral feeding. Parents gave a history of tachypnea and feeding difficulty to his doctors. He presented 
twice to the emergency room in respiratory distress. At 4 months of age, while in hospital for a pulmonary infection, 
he had an echocardiogram that revealed a pulmonary artery sling. We review the literature on this vascular anomaly, 
discuss its diagnosis and management, and critique the clinical thinking that determined this child’s course from the 
perspective of availability heuristics.
Keywords: Pulmonary artery sling, Stovepipe trachea, Congenital, Cardiovascular, Neonate, Infant, Developmental 
origins of health and disease
© 2016 Healey et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License 
(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, 
provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, 
and indicate if changes were made.
Introduction
Pulmonary artery sling (PAS) is a very rare cause of pedi-
atric pulmonary distress and tracheomalacia. The esti-
mated prevalence of the disease was first determined in 
2008 as 59 per million in a large-scale pre-sports partici-
pation cardiovascular screening study of 186,213 school-
aged children by Yu et al. (2008). All patients identified in 
the study were unrecognized due to non-specific symp-
toms of asthmatic cough and recurrent broncho-pulmo-
nary infections. We present here a male child initially 
admitted to the neonatal intensive care unit (NICU) with 
respiratory distress who turned out to have a PAS. We 
also review the literature on PAS and discuss its diagnosis 
and management, and critique the clinical thinking that 
determined this child’s course from the perspective of 
availability heuristics.
PAS is a very rare congenital disorder where the left 
pulmonary artery (LPA) arises outside the pericardium as 
a posterior branch off the right pulmonary artery (RPA). 
It then circles around the distal trachea and right main 
stem bronchus as it travels between the trachea and 
esophagus toward the hilum of the left lung. In doing so, 
it indents these structures and displaces the trachea to 
the left. The ligamentum arteriosum or the ductus arte-
riosus originates from the main pulmonary artery (MPA) 
and passes anteriorly and superiorly to the left main stem 
bronchus to join the descending thoracic aorta, com-
pleting the vascular ring (Fiore et  al. 2005). PAS mani-
fests clinically with significant tracheal and esophageal 
symptoms.
Case description
A newborn boy was admitted to the NICU for respiratory 
distress. He was born at 34 weeks gestational age, twin of 
Open Access
*Correspondence:  David.Healey@seattlechildrens.org 
1 Division of Developmental Medicine, Seattle Children’s Hospital, 
University of Washington, Seattle, WA, USA
Full list of author information is available at the end of the article
Page 2 of 4Healey et al. SpringerPlus  (2016) 5:31 
a dichorionic diamniotic pregnancy, at appropriate weight. 
His mother was 21 years old, G4P1, with all labs negative, 
in preterm labor. The other twin was normal. His mother 
had received regular prenatal care as well as adequate 
corticosteroids before delivery. Routine resuscitation was 
given to him. His Apgar scores at 1 and 5 min were 9 and 
9. Within minutes, he began to develop significant respira-
tory distress and had diminished air entry on auscultation.
Two flat and one right lateral decubitus chest X-rays 
were performed to rule out pneumothorax. They showed 
a 5.5 cm left pneumothorax as well as hazy densities sug-
gestive of respiratory distress syndrome (RDS). The baby 
was stable on nasal intermittent positive pressure ventila-
tion (NIPPV) with saturations continuously greater than 
90 %. On day 3, the patient was weaned to nasal cannula 
and subsequently to room air and was stable until dis-
charge. No cardiac abnormalities were evident.
At 2 months of age, the patient presented to the emer-
gency department for cough. Scant wheezes were aus-
cultated. He was diagnosed to have a viral respiratory 
infection and was discharged home. At 4 months of age, he 
presented with subcostal retractions and bilateral wheez-
ing from respiratory syncytial virus (RSV) bronchiolitis 
and was admitted. His mother provided an interim history 
of persistent tachypnea since birth and feeding difficulty 
when compared to his twin sister. Radiographs of the chest 
showed no pleural effusion, pneumothorax, or pulmonary 
congestion. However, hyperinflation and increased peri-
bronchial markings suggested underlying reactive airway 
disease, and minimal increased opacity in the right infrahi-
lar region suggested a focal infiltrate or atelectasis. Barium 
contrast esophagogram was performed to investigate the 
feeding difficulties. It revealed a subtle contour change in 
the esophagus above the level of the carina. At this time, a 
pediatric resident auscultated a systolic murmur at the left 
upper sternal border, and cardiology was consulted.
Cardiac echo revealed a PAS with the LPA arising from 
the RPA (Figs. 1, 2). There was good left ventricular func-
tion with mild hypoplasia of the LPA. Esophageal fluor-
oscopy showed a concave contour change in the anterior 
esophagus just above the level of the carina with no sig-
nificant reduction in the esophageal lumen size at this 
level. A bronchoscopy was performed and a 3D chest CT 
was obtained (Fig. 3).
At 8  months of age, the patient underwent surgical 
repair of the PAS by re-implantation of the LPA from the 
MPA without the need of tracheoplasty. He is since faring 
well.
Discussion
In this report we describe a premature infant with 
respiratory distress whose PAS was not diagnosed 
until 4  months of age. This case highlights the typical 
presentation of PAS, methods of diagnosis of such a vas-
cular ring, and the importance of including rare diagno-
ses within the differential.
Current understanding is that PAS has multifactorial 
causes. Genetic-related factors may play a role, as seen in 
case reports of PAS in identical twins and in patients with 
trisomies 18 and 21. A pulmonary artery is formed dur-
ing prenatal life from two portions; one that derives from 
the ventral sixth branchial arch, and another that derives 
from a postbranchial vessel. This latter portion, in turn, 
arose from the pulmonary capillary plexus that envelops 
the lung bud. Pu and colleagues hypothesized that if the 
left postbranchial vessels cannot connect to the left sixth 
branchial arch, then they might capture a vascular supply 
from the most nearby major artery. When such a connec-
tion is made to the right sixth branchial arch through the 
Fig. 1 Transthoracic echocardiogram showing main pulmonary 
artery (MPA) giving rise to right pulmonary artery (RPA) with arrow 
depicting left pulmonary artery (LPA) arising from its distal segment
Fig. 2 Transthoracic echocardiogram with Doppler showing main 
pulmonary artery (MPA), right pulmonary artery (RPA) and left pulmo-
nary artery (LPA) flow. Note turbulence within the LPA segment as it 
courses between the trachea and esophagus
Page 3 of 4Healey et al. SpringerPlus  (2016) 5:31 
embryonic peritracheal mesenchyme between the tra-
chea and the esophagus, a PAS results (Pu et al. 1996).
The first to describe the condition were Glaevecke and 
Doehle in 1897 (Glaevecke and Doehle 1897). Contro 
et  al. used the term “vascular sling” to distinguish this 
entity from a vascular ring (Contro 1958). Several other 
anatomical characteristics describe this disorder. The 
trachea has complete rings in 50–65 % of cases. Instead 
of having the normal U shape, the cartilage is circular, 
hence the term “stovepipe trachea.” In this case, there is 
no membranous trachea—there is a narrowing of the seg-
ment with complete rings. Because of the compression of 
the lower trachea, patients often present with wheezing 
and stridor. Atelectasis, air trapping and pneumonia arise 
from bronchial compression mostly on the right. Sudden 
death can result in neonates and infants from failure to 
recognize these symptoms (Sade et al. 1975).
A population of 18 patients was studied by Pawade 
et al. Among these, symptoms were first noticed between 
1 day and 4 months of age. All had wheeze, 11 had addi-
tional stridor, 7 had recurrent chest infections and 3 fed 
poorly and failed to thrive. Predominant signs were stri-
dor, tachypnea, and intercostal retractions (Pawade et al. 
1992). Gikonyo et  al. reported on 130 cases and found 
that the ratio of male to female patients was 3:2. Of the 
130 patients surveyed, 90  % were symptomatic; 90  % 
of these were symptomatic in the first year of life, and 
nearly half of these were symptomatic in the newborn 
period. When present, symptoms were usually those 
of respiratory obstruction characterized by stridor and 
wheezing. The obstruction was maximal during inspira-
tion and there was no associated dysphagia (Gikonyo 
et al. 1989).
PAS is frequently associated with tracheal anomalies, 
congenital heart disease, and lung abnormalities. The 
development of noninvasive imaging modalities such as 
computed tomography (CT), ultrasonography and mag-
netic resonance imaging has led to increased reports of 
this entity. Chen et al. reported the relative frequencies of 
such anomalies in eighteen cases of LPA sling and used Chi 
square tests to compare the probability of coexistence of the 
anomalies. They found that 100 % presented with tracheal 
stenosis, with a high incidence of combined right tracheal 
bronchus (22  %), underdeveloped right lung (22  %), per-
sistent left superior vena cava (22 %) and left PDA (39 %). 
There was a statistically significant correlation of associated 
anomalies between those with PAS as compared to those 
without (Chen et al. 2007). Coexisting diffuse tracheal ste-
nosis, creating a ring-sling complex, is identified in up to 
65 % of patients with PAS. Typically, stenosis of the trachea 
is due to complete tracheal rings and ranges from a pro-
found degree of hypoplasia of the entire tracheobronchial 
tree to a discrete stenosis. Interestingly, despite compres-
sion of the tracheobronchial tree by the sling, tracheoma-
lacia is usually not a feature. Congenital heart defects are 
found in 50 % of PAS cases, the most common being atrial 
and ventricular septal defects, patent ductus arteriosus, left 
superior vena cava and Tetralogy of Fallot (Sade et al. 1975).
As described by Hraška et  al., treatment of patients 
with PAS requires close collaboration of pediatric car-
diac surgeons and their medical counterparts. Diagnosis 
of PAS is optimally made using echocardiography, as it is 
rapid and non-invasive. All infants should undergo bron-
choscopy to rule out tracheal stenosis secondary to con-
genital complete tracheal rings (Hraška et al. 2009).
PAS, once diagnosed, is an indication for surgical 
repair. Repair using a strategy of median sternotomy, 
cardiopulmonary bypass (CPB), LPA division and re-
implantation into the MPA with simultaneous tracheal 
repair takes preference. Tracheal repair should be consid-
ered only in clinically symptomatic patients. Coexisting 
intracardiac pathology is repaired or palliated at the same 
time. The postoperative care of these patients requires 
close vigilance by pediatric intensivists, anesthesiolo-
gists, and pediatric cardiac surgeons. The management 
of the reconstructed trachea requires close collaboration 
among these specialties in order to achieve the best long-
term result (Hraška et  al. 2009; Backer et  al. 1999). The 
clinical outcome of patients with PAS is generally excel-
lent—the outcome depends mostly on other medical 
issues, such as the associated tracheal lesions and com-
plex cardiac anomalies.
Fig. 3 Posterior view of 3D computed tomography angiogram 
reconstruction showing the main pulmonary artery (MPA) giving 
rise to the left (LPA) and right (RPA) pulmonary arteries. A pulmonary 
artery sling is formed as the LPA makes an acute angle encircling the 
trachea (Tr), runs up against the esophagus (Eso), and finally passes 
anterior to the aorta (Ao)
Page 4 of 4Healey et al. SpringerPlus  (2016) 5:31 
We therefore suggest that the threshold to do an 
echocardiogram should be low in a neonate presenting 
with pneumothorax, especially when there may be no 
acute precipitating factors such as positive pressure ven-
tilation (PPV) being administered. The initial diagnosis 
of this patient was pneumothorax and associated RDS, 
even in the absence of PPV. The patient’s atelectasis and 
air trapping arose from bronchial compression mostly on 
the right, as is commonly seen in PAS. This infant’s PAS 
could have been picked up at birth if echocardiography 
would have been performed in the NICU. Likewise, other 
doctors later involved in the infant’s care should have 
taken into account the fact that he had wheezing that did 
not respond to albuterol, feeding intolerance, and over-
all did worse than his twin sister. These details about the 
child’s problems were communicated by his parents, and 
they were dismissed.
Our case and the mistakes that were made along the 
way illustrate the shortcomings of a clinical thinking 
mode that begins on the wrong path, with biased judge-
ment. The tendency to rely on the first thoughts toward a 
diagnosis, rather than alternative, less likely explanations, 
is an example in the medical domain of a psychological 
process called the availability heuristic (Groopman 2007).
Conclusions
The authors present the above case as a reminder to pedi-
atric colleagues that we are on the front line of diagno-
sis, must remain vigilant, and when appropriate generate 
self-questions about the specific pieces of the clinical 
picture that simply do not fit. Assuming that all wheez-
ing is some form of reactive airway disease in a pediat-
ric patient, to diagnose the things that we already have 
in mind, may beget the misfortune for the patient of our 
having missed the very rare yet critically important dis-
ease entity.
Abbreviations
PAS: pulmonary artery sling; NIPPV: nasal intermittent positive pressure ventila-
tion; RSV: respiratory syncytial virus; NICU: neonatal intensive care unit; RDS: 
respiratory distress syndrome; LPA: left pulmonary artery; RPA: right pulmonary 
artery; MPA: main pulmonary artery; CPB: cardiopulmonary bypass.
Authors’ contributions
All authors read and approved the final manuscript.
Author details
1 Division of Developmental Medicine, Seattle Children’s Hospital, Univer-
sity of Washington, Seattle, WA, USA. 2 Department of Pediatrics, New York 
Methodist Hospital, 506 Sixth Street, Brooklyn, NY 11215, USA. 3 Weill Cornell 
Medical College, New York, NY, USA. 4 Department of Internal Medicine, 
Elmhurst Hospital, Queens, NY, USA. 5 Icahn School of Medicine at Mt. Sinai, 
New York, NY, USA. 
Competing interests
The authors declare that they have no competing interests.
Received: 13 July 2015   Accepted: 22 December 2015
References
Backer CL, Mavroudis C, Dunham ME, Holinger LD (1999) Pulmonary artery 
sling: results with median sternotomy, cardiopulmonary bypass, and 
reimplantation. Ann Thorac Surg 67(6):1738–1745
Chen SJ, Lee WJ, Lin MT, Wang JK, Chang CI, Chiu IS et al (2007) Left pulmonary 
artery sling complex: computed tomography and hypothesis of embryo-
genesis. Ann Thorac Surg 84(5):1645–1650
Contro S, Miller RA, White H, Potts WJ (1958) Bronchial obstruction due to 
pulmonary artery anomalies. I. Vascular sling. Circulation 17(3):418–423
Fiore AC, Brown JW, Weber TR, Turrentine MW (2005) Surgical treatment of pul-
monary artery sling and tracheal stenosis. Ann Thorac Surg 79(1):38–46
Gikonyo BM, Jue KL, Edwards JE (1989) Pulmonary vascular sling: report of 
seven cases and review of the literature. Pediatr Cardiol 10(2):81–89 
(Spring)
Glaevecke H, Doehle W (1897) Ueber eine seltene angeborene anomalie der 
pulmonalarterie. Munch Med Wochenschr 44:950–951
Groopman, Jerome. How Doctors Think. Houghton Mifflin. 2007
Hraška V, Photiadis J, Haun C, Schindler E, Schneider M, Murin P et al 
(2009) Pulmonary artery sling with tracheal stenosis. Multimed Man 
Cardiothorac Surg 2009(123):mmcts.2008.003343. doi:10.1510/
mmcts.2008.003343
Pawade A, de Leval MR, Elliott MJ, Stark J (1992) Pulmonary artery sling. Ann 
Thorac Surg 54(5):967–970
Pu WT, Chung T, Hoffer FA, Jonas RA, Tal G (1996) Diagnosis and management 
of agenesis of the right lung and left pulmonary artery sling. Am J Cardiol 
78:723–727
Sade RM, Rosenthal A, Fellows K, Castanaeda A (1975) Pulmonary artery sling. J 
Thoracic Cardiovasc Surg 69:333–346
Yu JM, Liao CP, Ge S, Weng ZC, Hsiung MC, Chang JK, Chen FL (2008) The 
prevalence and clinical impact of pulmonary artery sling on school-aged 
children: a large-scale screening study. Pediatr Pulmonol 43:656–661


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Perinatal/Neonatal case presentation: pulmonary artery sling associated with respiratory distress

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