Pediatric vascular ring outcomes for surgically repaired vs. unoperated children: a single-center experience

Introduction

Alterations in the embryologic development, more specifically in the timely partial regression of segments from the six pairs of primitive aortic arches lead to various forms of complete or incomplete vascular rings (1).

These anomalies represent 1% of all congenital cardiovascular abnormalities although this might be an underestimation since some forms of vascular rings might be totally asymptomatic (2).

Their phenotypic expression is highly variable, from asymptomatic to severe forms related to the compression of either the esophagus and/or the trachea. With refinement in prenatal screening, the proportion of fetal diagnosis has recently increased (3).

Symptomatic patients require prompt surgical treatment, early in life for the most severe forms [pulmonary artery (PA) sling or double aortic arch (DAA)] or later on in the intermediate forms (right aortic arch and aberrant left arteria lusoria).

Besides, the optimal management in mildly symptomatic and in asymptomatic neonates and infants is currently a matter of debate (4,5). While some advocate a conservative approach in fetal-diagnosed patients remaining asymptomatic after birth, others promote a more radical approach. In a recent UK survey, 20% of the responders advised surgical repair in asymptomatic patients (6). Moreover, a detailed surgical algorithm for asymptomatic patients with a diagnosis of vascular ring was recently proposed by the Chicago group, one of the leading center on the subject (3).

Finally, though most studies reported on short and mid-term outcomes, a recent meta-analysis underscored that despite surgical repair, 40% of those patients remained symptomatic at follow-up (7).

In the view of those contemporary studies questioning whether vascular ring per se was (or not) a surgical indication in asymptomatic patients, some of our own pediatric cardiologists felt that we had had historically a large share of asymptomatic patients that had been referred to surgery and whether we should modify our algorithm.

The purpose of this study was to evaluate the management of patients with a diagnosis of vascular ring at our center over the last three decades with an institutional bias towards surgical treatment. Our focus of interest was placed on long-term follow-up, as well as to better define the place of surgery in asymptomatic patients. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1526/rc).

Methods

Ethical statement

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). This retrospective analysis was approved by our Institutional Ethical Board (Cliniques Universitaires Saint-Luc, Brussels, Belgium, IRB 2021/22-03/ID 141) and individual consent for this retrospective analysis was waived.

Patients and data collection

From the institutional database of the congenital cardiac center at the Cliniques Universitaires Saint-Luc, Belgium, between 1989 and 2019, we identified 82 consecutive pediatric patients (<18 years old) with a diagnosis of vascular ring.

Patients with associated complex congenital heart diseases (CHDs) were excluded. Patient’s charts were retrospectively reviewed for demographic data, genetic syndromes, associated anomalies, symptoms at presentation, anatomy of the vascular ring, and diagnostic modalities.

Vascular rings were classified according to the International Congenital Heart Surgery Nomenclature and Database Committee (ICHSNDC) (8).

Operative procedures, postoperative complications, and outcome data were also recorded.

To obtain information on residual symptoms and the use of medication at follow-up, outpatient clinical records from the pediatric cardiology or pneumology departments were reviewed. For those patients followed in other institutions, a web-based questionnaire was sent to the referring pediatric cardiologist or the treating physician (Appendix 1). Overall, complete follow-up was available in 76 out of 82 patients (93% completeness).

Statistical analysis

Continuous data are presented as mean ± standard deviation or median and interquartile range (IQR) for nonparametric data. Normality of the distribution was assessed with the Shapiro-Wilk test. Categorical data are presented as numbers and proportions and compared with the chi-square test or the Fisher’s exact test, if appropriate. Differences between means or medians were compared using unpaired Student’s t-test or Mann-Whitney U test, according to the distribution.

The statistical significance of differences between more than two groups was tested by one-way analysis of variance (ANOVA) with a Bonferroni post-hoc test.

All statistical analyses were performed using the IBM SPSS Statistic version 26 (IBM Corp., Armonk, NY, USA).

Results

Demographic and anatomical variants

From 1989 to 2019, 82 patients were diagnosed with some form of vascular ring at Cliniques Universitaires Saint-Luc.

Five anatomic variants of vascular ring were identified (Table 1). Right aortic arch with aberrant left subclavian artery (RAA and ALSA) and left ligamentum arteriosum was the most frequent diagnosis (43 patients, 52.4%). Associated Kommerell diverticulum (KD) was present in 14 patients (32.6%).

A DAA was the second most frequent variant (33 patients, 40.2%). A right dominant arch was present in nearly two-thirds of those patients (63.6%), whereas balanced arches or a left dominant arch were less frequently encountered (21.2% and 15.1%, respectively).

PA sling (3 patients, 3.7%) occurred infrequently. Finally, an innominate artery compression syndrome was diagnosed in 3 patients (3.7%).

Symptoms

Table 2 provides detailed information on symptoms at the time of diagnosis. Sixty-nine patients (84%) were symptomatic, whereas 13 patients (16%) had no symptoms.

In our cohort, clinical presentation was mostly suggestive of some form of airway compression (55 patients, 67%) but gastro-intestinal symptoms were also present in 45 patients (55%).

Among respiratory symptoms, recurrent infections, stridor (or wheezing), exercise or feeding intolerance, and cough were seen in 43%, 39%, 13%, and 18% respectively. Asthma, cyanosis, and acute respiratory distress syndrome were unfrequently encountered. At the time of evaluation, inhaled therapy was provided in 9 patients (11%).

Among gastro-intestinal symptoms, gastro-esophageal reflux, dysphagia, and swallowing dysfunction (aspiration) were observed in 33%, 26%, and 13% respectively. Antacid or proton pump inhibitors were given in 20 patients (24%).

Among the 13 asymptomatic patients, there were also 9 RAA and ALSA (9/43, 21%) and 4 DAA (4/33, 12%).

Regardless of presence of symptoms, DAA was thought to be an absolute indication for surgical repair during the study period. Associated cardiac anomalies requiring surgical repair, distant location from our center, and/or parental stress of a “follow-up only” strategy following the diagnosis of RAA and ALSA were among the reason for surgery in those children.

Three patients with RAA and ALSA were treated conservatively. Recurrent respiratory tract infection and dysphagia (or regurgitation) were present in two patients whereas one patient was asymptomatic.

Diagnosis

Prenatal diagnosis by fetal echocardiography was present in 17% of our cohort. After birth, transthoracic echocardiography (82%), and barium swallow studies (71%), together with chest X-ray, were the most frequent imaging modalities to confirm the diagnosis of vascular ring. Overall, computed tomography (CT) scan, angiography, and magnetic resonance imaging (MRI) provided additional anatomic details in 43%, 26%, and 16% respectively. Bronchoscopy was performed in 14 patients (17%).

In the early cohort (1988–2010; 48 patients), catheterization (n=16), CT scan (n=20), and MRI (n=8) confirmed transthoracic echocardiography diagnosis in nearly 90% of patients. Barium swallow was the mostly used modality to confirm esophageal compression.

In the more recent cohort (2010–2018; 34 patients), catheterization was only performed in four patients, whereas CT scan/MRI studies were performed more frequently with or without performing the barium swallow study.

In the 32 patients with the most severe respiratory symptoms, airway compression was assessed either by CT scan/MRI (n=26) and/or bronchoscopy (n=14) at the time of preoperative evaluation (Table 3).

Operative details

Overall, 79 patients (96%) underwent surgical repair. The operation was performed by thoracotomy in 71 (90%). Sternotomy and video-assisted thoracoscopy were used in 5 patients (6.3%) and 3 patients (3.8%), respectively.

The median age and weight at surgery were 13 (IQR, 4.4–48) months and 9.6 (IQR, 6.4–16.9) kg. Nearly half of the patients were either neonates or infants (39/79, 49%) (Figure 1). Among those, vascular ring diagnoses were PA sling (n=3), innominate artery compression syndrome (n=3), DAA (n=23), and RAA and ALSA (n=10).

Figure 1 Histogram of age distribution at the time of diagnosis in patients with vascular ring (n=86).

For the 12 asymptomatic patients who underwent surgical repair, the mean age and weight at repair was 59 months and 19 kg, respectively.

In three patients with additional ’simple’ CHD diagnosis, a concomitant surgical procedure was performed: tetralogy of Fallot (TOF) repair (n=1) and coarctation repair (n=2). All had RAA and ALSA dictating vascular repair together with the repair of the associated CHD diagnosis.

Infants with diagnosis of PA sling and/or innominate artery compression syndrome were operated earlier (mean age at repair: 52 and 169 days, respectively), whereas patients with DAA and RAA and ALSA were operated later in life (mean age at repair: 19 and 57 months, respectively). These intergroup differences in the timing of surgical repair were of borderline significance (ANOVA P=0.06). The frequency of symptoms such as cyanosis (23% vs. 0%, P=0.001), wheezing (15% vs. 0%, P=0.01), or stridor (48% vs. 19%, P=0.01) was correlated with age at repair, all being mostly prevalent in neonates and infants.

Treatment of the vascular ring consisted of division of the non-dominant arch together with division of the ligamentum arteriosum in DAA and division of the ligamentum arteriosum in RAA and ALSA. In this subgroup, a KD was present in 14 patients and was treated by resection only if its diameter was 150% or greater than the intra-thoracic portion of the subcarinal angle (SCA) (n=2/14).

The three patients with PA sling underwent reimplantation of the left pulmonary branch in the main PA under beating heart cardiopulmonary bypass, one of them undergoing a staged repair of coarctation of the aorta during the same hospitalization. Intra-operative bronchoscopy demonstrated relief of the trachea-bronchial compression without fibrous ring in the two severely symptomatic neonates, whereas the third patient’s only symptoms of his pulmonary sling was dysphagia.

Among the three patients with innominate artery compression syndrome, two had an anterior aortopexia (early in the series) and one patient had innominate artery translocation more proximally on the ascending aorta.

Despite concomitant clinical and/or bronchoscopic features of tracheobronchomalacia (TBM) in 19 patients (22%), no concomitant tracheal procedures were performed at the time of vascular ring repair.

In-hospital morbidity and mortality

There was no in-hospital mortality. The median time to extubation was 1 (IQR, 0.3–3) days. The median pediatric intensive care unit (PICU) stay and overall hospital stay were 1 (IQR, 1–2) and 7 (IQR, 6–9) days, respectively.

Table 4 provides a detailed description of postoperative morbidities. Fourteen patients (18%) encountered some form of postoperative complications. Pneumothorax and pulmonary atelectasis occurred in 7 patients (8.9%) and 5 patients (6.3%), respectively. Infection occurred in 3 patients (3.8%): two pneumonia and one catheter-related bacteriemia. Chylothorax occurred in a single patient (1.3%) and was treated conservatively. One patient required early reintubation on the second postoperative day. Tracheo-bronchoscopy demonstrated glottis and sub-glottis edema, together with moderate distal tracheomalacia and right upper bronchus plug. This patient was successfully extubated on postoperative day 7 without requiring additional treatment.

Recurrent laryngeal nerve palsy and phrenic nerve palsy were diagnosed in one patient each.

Among the subgroup of asymptomatic patients undergoing vascular ring repair (n=12), one chylothorax (see above) and three pleural effusions were recorded. All complications were treated conservatively.

Follow-up

At a median follow-up of 54 (IQR, 23–118) months, 20 patients (24%) still experienced some form of symptoms. There was no significant difference whether the patient was diagnosed in utero or after birth (40% vs. 24%, P=0.44).

There were two late reoperations related to the index operation (2.5%). The first patient (diagnosis of RAA and ALSA) was initially treated by division of the ligamentum arteriosum at 3 years of age. Parents noticed recurrence of dysphagia within the first year of follow-up. Barium studies and trachea-bronchoscopy confirmed a prominent lusoria without associated malacia. Resection of KD without subclavian reimplantation was performed at age 5 years (Angio-MRI had demonstrated an incomplete polygone of Willis).

The second patient (diagnosis of DAA-left dominant) presented with a late recurrence (68 months) of exertional stridor. Trachea-bronchoscopy and MRI studies demonstrated extrinsic compression with a 50% diameter reduction of the distal trachea without malacia. Anterior aortopexy of the LAA was performed with complete resolution of symptoms. Both patients experienced uncomplicated hospitalizations.

Among patients with persisting or recurrent respiratory symptoms (13/79), the most common feature was asthma (seven patients). All patients with asthma were under medical treatment (aerosol therapy mostly). Recurrent respiratory tract infections and stridor were documented in three and three patients (including one reoperation, as above), respectively.

Among patients with persisting or recurrent gastro-intestinal symptoms (13/79), the most common feature was gastro-esophageal reflux (11 patients). Half of those were treated with antacid or proton pump inhibitors. Persistent dysphagia was reported in a single patient. Table 5 provides a detailed description of symptoms prior to vascular ring repair (or conservative treatment) and symptoms at follow-up.

At follow-up, among the three unoperated patients, one patient remained symptomatic (recurrent respiratory tract infection) whereas two patients were free of symptoms.

Discussion

Vascular rings represent a rare congenital cardio-vascular entity with only 82 patients diagnosed over 30 years in a tertiary-care university hospital. Its phenotypic expression is highly variable, from asymptomatic to severe forms related to the compression of adjacent mediastinal structures. In agreement with previously published studies, RAA and ALSA and DAA were the most frequently encountered anatomic variants found in our cohort (9,10).

Most of our patients with vascular ring were diagnosed before 2 years of age, and symptoms were present in 84% of them. Anatomy generally dictated the timing of surgery, with PA sling representing the most severe form of vascular ring which required surgical repair in the neonatal period exclusively. The majority of patients with DAA or innominate artery compression syndrome were operated within the first year of life whereas RAA and ALSA patients were operated later on, unless antenatal diagnosis was present.

Diagnostic modalities used in this series are in agreement with previously published studies, with initial assessment by transthoracic echocardiography and barium swallow studies, and further anatomic evaluation made by CT scan and/or MRI (angiography in the early period) (11,12). However, preoperative bronchoscopy was underused in our historical cohort considering the current guidelines suggested by centers of expertise (3,6), in which a complete evaluation of the respiratory tract is advocated.

Our rate of prenatal diagnosis was low: only 14 patients (16%). The extensive period of inclusion certainly played a role: from 2010, 11 out of 36 patients (31%) had a prenatal diagnosis (or suspected) of vascular ring (vs. 6% prior to 2010). Secondly, we hypothesize that such a low prenatal diagnosis rate could be explained by our referral pattern, since most of the patients in this cohort were late referrals to our tertiary care center from peripheral hospitals. As such our detection rate remained very far from the 70% to 80% rate reported in contemporary studies (13,14).

Importantly, in our cohort, patients with the most severe forms of vascular rings were not detected before birth.

Asymptomatic or mildly symptomatic patients are a peculiar subset of patients for whom there is an ongoing debate on the optimal management: “Should surgical repair be performed or not, and if surgery is advised, which type of ring repair particularly regarding the KD?” (2,4,6,13).

In this historical series, the prevalence of KD in RAA and ALSA was 32% and it was resected only if its diameter exceeded 150% of the intra-thoracic left SCA (8). With such a conservative approach, KD was resected in only 2 out of 14 patients (14%) and subclavian reimplantation was performed in a single patient.

As others, we currently believe that an enlarged KD represents an independent cause of compression of the posterior mediastinal structures. Consequently, resection of the KD at the index surgery could have achieved better outcomes on postoperative persisting symptoms (15). Indeed, KD resection was one of the two late reoperations (recurrence of dysphagia) with complete relief of symptoms at follow-up.

Moreover, late complications of persisting KD such as dissection and rupture have been reported (16,17).

Overall in-hospital morbidity was acceptable (18%) and consisted mostly in pleural effusions and pulmonary atelectasis. Recurrent (or phrenic) nerve palsy and chylothorax occurred in a single patient each (1.3%). Our results compared favorably to the 12% of chylothorax recently reported in a larger series (10).

In Binsalamah’s report, KD was diagnosed in 66% of their RAA and ALSA subgroup and resected at the time of repair in 32% of them. It is likely that our conservative surgical approach on the fate of the proximal subclavian artery has been influential on our low rate of mediastinal complications.

Therefore, in asymptomatic patients, we still consider it is reasonable to resect only the ligamentum arteriosum without addressing the KD in order to simplify the operative procedure and avoid severe complications.

Few studies have provided mid and long-term results on symptoms and ongoing medical treatment of patients following vascular ring repair. Altogether, at 5-year follow-up, 23% of our patients had persisting symptoms. The most common persisting or recurrent respiratory symptoms was asthma (9.4%), followed by stridor (3.5%).

Whereas some patients with vascular ring are undoubtedly misdiagnosed with asthma and others may be left with secondary TBM if treated late, we are confident that seven patients in our asthma subgroup were correct diagnosis. When contacting the primary caregiver of those children (93% follow-up completeness), a series of specific questions were raised (see Appendix 1).

All patients with asthma were under medical treatment. As asthma is unlikely to be influenced by the surgical relief of the vascular ring, we observe that nearly 90% of our patients were free from vascular ring-related respiratory symptoms at late follow-up. Those data compare favorably to the 40% of residual symptoms reported by Rato et al. in their recent meta-analysis (7).

While a complete work-up of associated TBM at the time of vascular ring diagnosis is surely advisable, especially in patients with pulmonary sling, our data seem to support previous studies emphasizing that moderate forms of airway collapse are expected to improve by 1–2 years of age with somatic growth (18,19). Indeed, in a recent study on pulmonary sling repair, Choi et al. reported no mortality nor tracheal reintervention in 22 patients operated for PA sling without tracheal repair (19).

Despite the low frequency of tracheo-bronchial invasive imaging in this historical series (16%), only 3 out of 28 patients initially presenting with stridor/wheezing failed to improve spontaneously at follow-up. In fact, most of the patients operated on after 2001 presenting with stridor and/or wheezing had a bronchoscopic evaluation preoperatively or intraoperatively. In a single patient, an aortopexy was performed at a later stage with complete relief of symptoms. Such long-term results should be kept in mind when discussing concomitant additional tracheo-bronchial surgery with the parents and relatives at the time of surgical counseling.

Though debatable, in our patient evaluation, if a preoperative CT scan demonstrates a normal-size and normal-shape tracheo-bronchial tree and the patient with asymptomatic or with mild respiratory symptoms, we do not perform bronchoscopy prior to vascular ring repair.

The most common persisting or recurrent gastro-intestinal symptoms was gastro-esophageal reflux (14%). Half of those patients were treated with antacid or proton pump inhibitors. These results are in agreement with earlier studies where persisting respiratory symptoms varied from 30% to 36% and severe gastro-intestinal symptoms such as swallowing was reported in 15% of patients (20,21).

Finally, it is interesting that among the three patients of our cohort treated conservatively, two had full resolution of their symptoms at late follow-up. In his historical series of 11 patients, Godtfredsen et al. similarly described 9 out of 11 unoperated patients free of symptoms after 5-year of follow-up (22).

Finally, innominate artery compression syndrome was the least frequently encountered anatomic variant in our series, but its clinical presentation was severe (stridor, malaise, or cyanosis) in all patients. Both anterior aortopexy (23) and innominate artery translocation (24) were performed with satisfactory results for both surgical alternatives.

Study limitations

First, this is a retrospective study of a small cohort of patient with a cross-sectional follow-up analysis of medical charts, as well as a web-based reporting form sent to the general pediatrician at the time of data collection (06/2018 to 06/2019). The design of the study did not allow us to study the effect of time on the improvements of symptoms.

Secondly, some of our patients had associated conditions that could explain continuation of symptoms (syndromic) and we did not perform postoperative imaging studies to measure the degree of surgical relief in this subgroup.

Thirdly, the small number of patients with complete evaluation of the trachea-bronchial tree at the time of vascular ring repair greatly limit the interpretation of our data on the effectiveness of a conservative approach on the trachea, though it is reasonable to assume that most patients initially presenting with stridor or wheezing had at least mild TBM.

Conclusions

Most patients with anatomic variants of vascular ring were symptomatic at the time of diagnosis, suffering predominantly from respiratory symptoms. Subtypes of vascular rings such as pulmonary slings or innominate artery compression syndromes require detailed preoperative evaluation and prompt surgical management. While 24% of patients remained symptomatic at long-term follow-up, half of those were asthma-related and medically controlled, resulting in nearly 90% of patients symptoms-free at mid-term follow-up.

Finally, surgery in asymptomatic patients resulted in minimal hospital morbidity, supporting the current recommendation of early surgical repair after meticulous preoperative evaluation of associated trachea-bronchial anomalies.

Acknowledgments

The authors thank Mrs. P. Segers for her expertise in editorial help.

Funding: None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1526/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1526/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1526/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1526/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). This retrospective analysis was approved by our Institutional Ethical Board (Cliniques Universitaires Saint-Luc, Brussels, Belgium, IRB 2021/22-03/ID 141) and individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Collins-Nakai R, McLaughlin P. How congenital heart disease originates in fetal life. Cardiol Clin 2002;20:367-83. v-vi. [Crossref] [PubMed]
2. Loomba RS. Natural History of Asymptomatic and Unrepaired Vascular Rings: Is Watchful Waiting a Viable Option? A New Case and Review of Previously Reported Cases. Children (Basel) 2016;3:44. [Crossref] [PubMed]
3. Stephens EH, Eltayeb O, Kennedy C, et al. Influence of Fetal Diagnosis on Management of Vascular Rings. Ann Thorac Surg 2022;113:630-6. [Crossref] [PubMed]
4. Buratto E, Konstantinov IE. Prenatal Diagnosis of Vascular Rings: Knowledge Is Power… or Is It? Ann Thorac Surg 2022;113:636-7. [Crossref] [PubMed]
5. Dodge-Khatami A. Commentary: If You Know About It, Why Not Just Fix It? Planning Surgical Repair on Asymptomatic Patients With Vascular Rings in the New Era of Prenatal Diagnosis. Semin Thorac Cardiovasc Surg 2021;33:503-4. [Crossref] [PubMed]
6. Vigneswaran TV, Hunter LE, Carvalho JS, et al. Management of prenatally detected vascular rings: a United Kingdom national survey. Cardiol Young 2023;33:1332-5. [Crossref] [PubMed]
7. Rato J, Zidere V, François K, et al. Post-operative Outcomes for Vascular Rings: A Systematic Review and Meta-analysis. J Pediatr Surg 2023;58:1744-53. [Crossref] [PubMed]
8. Backer CL, Mavroudis C. Congenital Heart Surgery Nomenclature and Database Project: vascular rings, tracheal stenosis, pectus excavatum. Ann Thorac Surg 2000;69:S308-18. [Crossref] [PubMed]
9. Depypere A, Proesmans M, Cools B, et al. The long-term outcome of an isolated vascular ring - A single-center experience. Pediatr Pulmonol 2019;54:2028-34. [Crossref] [PubMed]
10. Binsalamah ZM, Ibarra C, John R, et al. Contemporary Midterm Outcomes in Pediatric Patients Undergoing Vascular Ring Repair. Ann Thorac Surg 2020;109:566-72. [Crossref] [PubMed]
11. Hernanz-Schulman M. Vascular rings: a practical approach to imaging diagnosis. Pediatr Radiol 2005;35:961-79. [Crossref] [PubMed]
12. Snarr BS, Dyer A, Thankavel PP. Is There a Role for Echocardiography in Vascular Ring Diagnosis? J Am Soc Echocardiogr 2018;31:965-6. [Crossref] [PubMed]
13. Swarnkar P, Speggiorin S, Austin BC, et al. Contemporary surgical outcome and symptomatic relief following vascular ring surgery in children: effect of prenatal diagnosis. Eur J Cardiothorac Surg 2022;61:1260-8. [Crossref] [PubMed]
14. Evans WN, Acherman RJ, Ciccolo ML, et al. Vascular Ring Diagnosis and Management: Notable Trends Over 25 Years. World J Pediatr Congenit Heart Surg 2016;7:717-20. [Crossref] [PubMed]
15. Luciano D, Mitchell J, Fraisse A, et al. Kommerell Diverticulum Should Be Removed in Children With Vascular Ring and Aberrant Left Subclavian Artery. Ann Thorac Surg 2015;100:2293-7. [Crossref] [PubMed]
16. Braunberger E, Mercier F, Fornes P, et al. Aortic dissection of Kommerell's diverticulum in Marfan's syndrome. Ann Thorac Surg 1999;67:1160-2. [Crossref] [PubMed]
17. Fisher RG, Whigham CJ, Trinh C. Diverticula of Kommerell and aberrant subclavian arteries complicated by aneurysms. Cardiovasc Intervent Radiol 2005;28:553-60. [Crossref] [PubMed]
18. Hammond K, Ghori UK, Musani AI. Tracheobronchomalacia and Excessive Dynamic Airway Collapse. Clin Chest Med 2018;39:223-8. [Crossref] [PubMed]
19. Choi ES, Park CS, Kim DH, et al. Outcomes of pulmonary artery sling repair without tracheoplasty. J Thorac Cardiovasc Surg 2023;166:317-324.e1. [Crossref] [PubMed]
20. Schmidt AMS, Larsen SH, Hjortdal VE. Vascular ring: Early and long-term mortality and morbidity after surgical repair. J Pediatr Surg 2018;53:1976-9. [Crossref] [PubMed]
21. Callahan CP, Merritt TC, Canter MW, et al. Symptom persistence after vascular ring repair in children. J Pediatr Surg 2020;55:2317-21. [Crossref] [PubMed]
22. Godtfredsen J, Wennevold A, Efsen F, et al. Natural history of vascular ring with clinical manifestations. A follow-up study of eleven unoperated cases. Scand J Thorac Cardiovasc Surg 1977;11:75-7. [Crossref] [PubMed]
23. Gross RE, Neuhauser EB. Compression of the trachea by an anomalous innominate artery; an operation for its relief. Am J Dis Child (1911) 1948;75:570-4. [Crossref] [PubMed]
24. Hawkins JA, Bailey WW, Clark SM. Innominate artery compression of the trachea. Treatment by reimplantation of the innominate artery. J Thorac Cardiovasc Surg 1992;103:678-82. [Crossref] [PubMed]