A left pulmonary artery sling with left bronchiectasis in an adult patient: A case report and review of literature

Abstract

Pulmonary artery sling (PAS) is a rare congenital vascular anomaly, and is usually diagnosed during the infantile or fetal period. Adult presentation of PAS is rare. We report a 55‐year‐old woman with left pulmonary artery sling and left lung bronchiectasis, performing as persistent shortness of breath, coronary computed tomography angiography (CTA) showed the aberrant left pulmonary artery emerging from the right pulmonary artery and crossing to the left between the trachea and oesophagus. We experienced a rare adult case with LPAS and left bronchiectasis, stressing the importance of the anatomic abnormalities in such cases.

We report a 55‐year‐old woman with left pulmonary artery sling and left lung bronchiectasis, performing as persistent shortness of breath, coronary computed tomography angiography (CTA) showed the aberrant left pulmonary artery emerging from the right pulmonary artery and crossing to the left between the trachea and esophagus. We experienced a rare adult case with LPAS and left bronchiectasis, stressing the importance of the anatomic abnormalities in such cases.

INTRODUCTION

Pulmonary artery sling (PAS) is a rare congenital vascular malformation in which the left pulmonary artery crosses to the left lung between the trachea and the oesophagus from the right pulmonary artery, compressing the trachea and frequently coexisting with airway stenosis and cardiac malformations. ¹ During the infant period, patients typically have severe wheezing or even potentially fatal respiratory distress or pneumonia. Most patients could die during the first year of life if they are not properly diagnosed and treated. ² Therefore, adult patient with PAS is rare. We report a case of adult patient with a pulmonary sling anomaly and left lung bronchiectasis.

CASE REPORT

A 55‐year‐old woman with hypertension was sent to our hospital because she had been experiencing shortness of breath and chest tightness for over a year, which got worse after exercising and after catching a cold. She had a 10‐year history of hypertension and took amlodipine besylate on a daily basis at a dose of 5 mg. Her blood pressure was well‐controlled. Physical examination, ECG, transthoracic echocardiography, pro‐BNP, and plasma D‐dimer all revealed no noteworthy abnormalities. Coincidently, coronary computed tomography angiography (CTA) revealed an anomalous left pulmonary artery originating from the proximal part of right pulmonary artery, coursing posterior to the trachea and anterior to oesophagus to reach the left hilum, resulting in slight trachea compression and airway stenosis, and the transverse diameter of the trachea was 13.13 mm at the narrowest point (Figure 1A), while the maximum transverse diameter of the trachea without compression was 14.82 mm (Figure 1B). The compressed trachea on the mediastinal window could also be seen on the computed tomography (CT) chest images in sagittal view (Figure 1C). The bent left pulmonary artery also caused an increase in right pulmonary artery diameter (Figure 1A). Chest CT revealed that there was bronchiectasis in each of the left lobes, including diffuse cystic and columnar abnormalities (Figure 1D–F). When questioned, the patient denied having ever experienced any childhood coughing, respiratory distress, or feeding issues. She had moderate–severe mixed obstructive and restrictive pulmonary function impairment and a negative bronchodilation test.

FIGURE 1.

A 55‐year‐old female with left pulmonary artery sling. (A) CTA revealed an anomalous left pulmonary artery (L) originating from the proximal part of right pulmonary artery (R), coursing posterior to the main bronchus and anterior to oesophagus to reach the left hilum, resulting in slight trachea compression and airway stenosis, and the transverse diameter of the trachea was 13.13 mm at the narrowest point (black arrow). Right pulmonary artery diameter was enlarged due to the bent left pulmonary artery. (B) the maximum transverse diameter of the trachea without compression was 14.82 mm. (C) Sagittal CT images demonstrated the compressed trachea on mediastinal window. (D–F) CT showed bronchiectasis existed in each left lobe, diffuse cystic and columnar changes were observed on lung window

In light of the patient's modest symptoms and the fact that her oesophagus was not compressed, together with her own preferences, surgical intervention was not considered; instead, she was monitored in an outpatient clinic.

DISCUSSION

Pulmonary artery sling (PAS) is a rare congenital vascular anomaly defined as the anomalous origin of the left pulmonary artery from posterior wall of the proximal section of right pulmonary artery. To reach the left hilum, the left pulmonary artery travels posterior to the trachea and anterior to the oesophagus, forming a vascular ring that may squeeze the airway and oesophagus. ³ The anomalous left PAS is typically thought to be caused by a deformity of the left sixth aortic arch. ⁴ , ⁵

The majority of cases are discovered during the infant stage because of persistent coughing, dyspnea, wheezing, and respiratory infections. Most adult cases are asymptomatic or moderate, in contrast to newborn cases. In our analysis of the adult PAS literature published after 2010, we discovered a total of 10 adult cases (Table 1). ¹ , ⁶ , ⁷ , ⁸ , ⁹ , ¹⁰ , ¹¹ , ¹² , ¹³ Patients in our review had ages ranging from 29 to 72. In four cases, the trachea or oesophagus was compressed. Many of the patients were asymptomatic when they were identified through other conditions or medical exams. A few patients had chronic cough, recurring lung infection, and lung abscess. In this case, an adult patient experienced dyspnea following exercise, which relieved over time after calming down. Coronary CTA revealed, in accordance with the literature review, that the left pulmonary artery arose from the proximal section of the right pulmonary artery, traversed the trachea, and caused minor tracheal compression.

TABLE 1.

Literature review of adult PAS after 2010

No.	Author	Gender	Age	Chief compliant	Diagnosis	Image	Treatment	Outcome
1	Huang 2021	Female	56	Health examination	CTPA	No other findings	Follow‐up	Unspecified
2	Maldjian 2020	Male	72	Health examination	CTA	No other findings	Follow‐up	Not worse
3	Imoto 2019	Female	49	Recurrent pneumonia	CT	Two cavities with thickened walls in the right lung	Low dose macrolide therapy	Improvement
4	Miyazaki 2015	Female	33	Recurrent lung infections	CT	Ground‐glass opacity and traction bronchiectasis	Partial lung resection	Improvement
5	Marangoni 2013	Male	51	Mild dyspnea	CT	No other findings	Unspecified	Unspecified
6	Komoto 2013	Male	42	Pharyngeal discomfort	CT	A right mediastinal mass shadow	Unspecified	Unspecified
7	Komoto 2013	Female	36	Bloody sputum and wheezing	CT	No other findings	Unspecified	Unspecified
8	Odell 2011	Female	29	Dyspnea and cough	CT	Tracheomalacia	LPA reconstruction	Improvement
9	Nazeri 2011	Male	53	Chronic cervical pain	CT	No other findings	Follow‐up	Not worse
10	LaBelle 2010	Female	42	Dysphagia	CT	No other findings	LPA reconstruction	Improvement

Note: A literature review of the adult PAS after 2010 and found a total of 10 adult patients. Patients ranged in age from 29 to 72 years. Four cases were due to the compression of the trachea or oesophagus. A considerable number of patients were asymptomatic, diagnosed due to other diseases or health examination. A few patients presented with long‐term cough, recurrent lung infection and lung abscess. The images of six cases showed no other manifestations but PAS with or without tracheal and oesophageal compression, and other four cases demonstrated PAS complicated with cavities, ground‐glass opacity and traction bronchiectasis, mediastinal mass shadow or tracheomalacia.

According to research, the PAS is associated with cardiovascular anomalies such as ventricular septal defect, atrial septal defect, and patent ductus arteriosus in 30% of cases, ¹⁴ and PAS can combine with other multisystem abnormalities such as kidney and urinary tract dysplasia, urethral valves, congenital biliary atresia and anal atresia, but these are rare. ² Additionally, there is a considerable correlation between right lung hypoplasia, abnormal trachea or bronchi, and PAS. More than 50% of PAS patients exhibit tracheobronchial anomalies, such as tracheomalacia, stenosis, webs, or complete tracheal rings. ¹ The primary cause of respiratory distress and recurrent lung infections is considered to be focal extrinsic collapse of the distal trachea and proximal left mainstem bronchus brought on by PAS and tracheomalacia, which is particularly common in literature reviews. ⁸ Interestingly, this patient has no tracheal malformation, but shows left extensive bronchiectasis. In our literature reviews, the images of six cases showed no other manifestations but PAS with or without tracheal and oesophageal compression, and other four cases demonstrated PAS complicated with cavities, ground‐glass opacity and traction bronchiectasis, mediastinal mass shadow or tracheomalacia (Table 1). Miyazaki reported a 33‐year‐old woman who had traction bronchiectasis and ground‐glass opacity on her CT scans in 2015, ¹¹ however, there was no further information available regarding the relationship between PAS and bronchiectasis. Therefore, more research is needed to determine whether left extensive bronchiectasis and PAS are related.

The diagnostic techniques for PAS include echocardiography, CTA, bronchoscopy, magnetic resonance imaging (MRI) and so on. Congenital heart disease can be detected by echocardiography, but the relationship between the pulmonary artery and the trachea may be determined using a doctor's clinical judgement and other tests. As the literature analysis shows, noninvasive tests like CT and MRI are becoming more and more crucial in the identification of congenital cardiac disease complicated with tracheal deformity. The bronchoscope can detect the airway wall and vascular pulsation in the airway stenosis caused by the vascular ring, revealing the length and diameter of the narrow tracheal segment and the presence of tracheobronchial malformation. In addition, CTA demonstrated anomalies in the left pulmonary artery better than echocardiography. CTA, as cross‐sectional imaging, can demonstrate the relationship between structures as well as the severity and location of tracheal compression and provide a surgical treatment plan. Therefore, each examination has benefits and drawbacks, and choosing an examination properly might increase diagnostic accuracy.

Children with reoccurring lung infections and adults with severe symptoms caused by trachea and oesophageal compression appear to benefit from surgery. In our literature study, only 3 of the 10 patients underwent surgery. By using CT and bronchoscopy, a 29‐year‐old woman who presented with severe dyspnea and a chronic cough was diagnosed with PAS and tracheomalacia. Cardiopulmonary bypass was used to perform surgical resection of the vascular sling and reanastomosis to the main pulmonary artery by a median sternotomy. The operation was effective and respiratory symptoms disappeared. ⁸ A 42‐year‐old woman with PAS underwent left pulmonary artery reconstruction due to dysphagia brought on by oesophageal compression; after the operation, the symptoms of dysphagia, odynophagia, reflux, and aspiration were alleviated. ⁶ Because of recurring lung infections, a 33‐year‐old woman underwent partial lung resection; she recovered well. ¹¹ Asymptomatic adults typically have a better prognosis and require less surgical intervention, according to general consensus.

The patient in this case had PAS complicated with left extensive bronchiectasis, the following factors may have contributed to her moderate symptoms and survival. The mildly compressed trachea did not cause airway collapse and severe dysfunction. Furthermore, the extensive bronchiectasis on the left was consistently asymptomatic and free of recurrent respiratory infections. In conclusion, PAS may be a possibility for adults with dyspnea, cough, recurrent lung infection, or dysphagia, particularly if respiratory symptoms are not alleviated with regular bronchodilator treatment.

CONFLICT OF INTEREST

None declared.

ETHICS STATEMENT

The authors declare that appropriate written informed consent was obtained for the publication of this manuscript and accompanying images.

Lv L, Cheng X, Yu X, Cui C, Ji W, Wang N, et al. A left pulmonary artery sling with left bronchiectasis in an adult patient: A case report and review of literature. Respirology Case Reports. 2022;11:e01072. 10.1002/rcr2.1072

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.