Translocation of aberrant left subclavian artery and resection of Kommerell diverticulum during the concomitant repair of intracardiac anomalies

Abstract

OBJECTIVES

To assess the safety and efficacy of the translocation of the aberrant left subclavian artery (LSCA) and resection of the Kommerell diverticulum during the concomitant repair of intracardiac anomalies for paediatric patients who had a right-sided aortic arch.

METHODS

A retrospective review of paediatric patients who were diagnosed right-sided aortic arch, aberrant LSCA, Kommerell diverticulum and intracardiac anomalies between 2015 and 2019 was conducted. Patients who underwent translocation of the aberrant LSCA, diverticulum resection and concomitant intracardiac repair were included.

RESULTS

Eight patients underwent translocation of aberrant LSCA, diverticulum resection, ligamentum division and concomitant repair of the associated intracardiac anomalies. All patients were male. The median age was 1.3 years (range 0.4–5.5 years) and the median weight was 10.0 kg (range 6.1–21.0 kg). The most commonly combined intracardiac anomaly was a ventricular septal defect. Seven patients (87.5%) had preoperative respiratory or gastrointestinal symptoms. There was no early mortality and no postoperative complications. During the median follow-up of 23 months (range 4–43 months), no patient had residual respiratory or gastrointestinal symptoms. A postoperative computed tomography scan was performed in 3 patients, all of which showed patent LSCA–left carotid artery anastomosis.

CONCLUSIONS

Translocation of the aberrant LSCA and resection of the Kommerell diverticulum can be safely performed during the concomitant repair of intracardiac anomalies for paediatric patients. This approach could eliminate residual respiratory and gastrointestinal symptoms, and prevent reintervention in the future.

INTRODUCTION

Right-sided aortic arch with the aberrant left subclavian artery (LSCA) and Kommerell diverticulum is a rare form of congenital anomaly. The presence of a posterior ligamentum arteriosum results in a vascular ring that encircles the trachea and the oesophagus [1]. The classic therapy used to be the division of the ligamentum arteriosum to relieve the compression symptoms [2]. However, the retained Kommerell diverticulum has been known to compress the trachea independent of the action of the vascular ring, which may result in residual symptoms after ligamentum division [3, 4]. Since the early 2000s, a new surgical approach has been advocated for these patients during childhood that includes primary translocation of the aberrant LSCA, resection of the Kommerell diverticulum and ligamentum division [5]. This approach has been reported to achieve better relief of the symptoms and prevent late complications [6].

Right-sided aortic arch, aberrant LSCA and Kommerell diverticulum may present with concomitant intracardiac defects, such as ventricular septal defects (VSDs) [7]. The optimal approach for this combination of anomalies remains unclear. The purpose of this study is to assess the safety and efficacy of the translocation of the aberrant LSCA and resection of the Kommerell diverticulum among this group of patients during the concomitant repair of intracardiac anomalies.

MATERIALS AND METHODS

Study design

We collected data of paediatric patients with right-sided aortic arch, aberrant LSCA, Kommerell diverticulum and intracardiac anomalies from January 2015 to December 2019 at our centre. Patients who underwent concomitant intracardiac repair, diverticulum resection and translocation of aberrant LSCA were included. Electronic medical records were reviewed to obtain patient demographics, perioperative information and associated outcomes data. This study was approved by the Institutional Review Board and the need for patient consent was waived due to its retrospective nature.

Statistical analysis

Continuous data were expressed as median and ranges. Categorical data were expressed as counts and proportions. Statistical analyses were performed using the Statistical Package for Social Sciences, version 23.0 (SPSS, Inc., Chicago, IL, USA).

RESULTS

Patient characteristics

During the study period, 8 patients underwent translocation of aberrant LSCA, resection of the Kommerell diverticulum, ligamentum division and concomitant repair of the associated intracardiac anomalies. All patients underwent preoperative echocardiography and computed tomography (CT) scan to confirm the diagnosis (Fig. 1). All patients were male. The median age was 1.3 years (range 0.4–5.5 years) and the median weight was 10.0 kg (range 6.1–21.0 kg). The most commonly combined intracardiac anomaly was VSD, as shown in Table 1.

Figure 1:

Preoperative computed tomographic image of a patient with right-sided aortic arch, aberrant LSCA and Kommerell diverticulum. LCA: left carotid artery; LSCA: left subclavian artery.

Table 1:

Summary of preoperative baseline characteristics

Patent number	Gender	Age (years)	Weight (kg)	Respiratory symptoms	Gastrointestinal symptoms	Associated cardiac procedure
1	M	1.5	10.0	Stridor		Tetralogy of Fallot
2	M	0.5	6.1	Stridor		ASD, coarctation of aorta
3	M	0.4	7.5	Stridor		ASD
4	M	1.1	10.8	Stridor		VSD, right ventricular outflow tract obstruction
5	M	1.2	10.0	Recurrent infections		VSD
6	M	3.4	16.5			VSD
7	M	5.5	21.0	Stridor	Dysphagia	VSD
8	M	3.5	9.5	Recurrent infections		VSD, supravalvular aortic stenosis, branch pulmonary artery stenosis

ASD: atrial septal defect; VSD: ventricular septal defect.

All patients but 1 had preoperative respiratory or gastrointestinal symptoms, including stridor, recurrent respiratory infection and dysphagia. The patient without respiratory or gastrointestinal symptoms was found to have a right-sided aortic arch and a possible aberrant LSCA during the preoperative echocardiography. The following CT scan confirmed the diagnosis of aberrant LSCA and large Kommerell diverticulum (>1.5 times the size of the LSCA) requiring surgical intervention.

Surgical technique

All operations were performed through a standard median sternotomy. The LSCA, the left carotid artery (LCA), the Kommerell diverticulum and the left ligamentum arteriosum were dissected as much as possible. Care was taken not to injure the adjacent structures, especially the thoracic duct. The Kommerell diverticulum was dissected all the way to its origin from the descending aorta. The left ligamentum was divided and oversewn to relieve the vascular ring. After systemic heparinization, a clamp was placed at the junction of the descending aorta and the Kommerell diverticulum. The pulse oximetry and blood pressure in the lower extremity was monitored to prevent coarctation. Another clamp was placed at the distal LSCA. The diverticulum was resected and the opening of the descending aorta was oversewn with a running suture. The clamp on the descending aorta was released and another clamp was placed on the LCA. After confirming the absence of significant cerebral oximetry decrease, the LSCA was anastomosed to the LCA in side-to-end fashion with a running suture. The clamps on the LCA and LSCA were released after careful deairing.

Cannulation of the ascending aorta and both vena cava was performed in a routine fashion. Cardiopulmonary bypass (CPB) was commenced, the ascending aorta was cross-clamped directly and the cardioplegia was administered. Repair of the intracardiac anomalies was performed using standard techniques. After the completion of the repair, deairing was performed and the heart was evaluated by transoesophageal echocardiography. The patient was weaned from CPB and the chest tubes were placed.

Outcomes

There was no early mortality. None of the patients had postoperative chylous effusion, recurrent laryngeal nerve injury or neurological deficits. The median intensive care unit stay was 47 h (range 15–600 h) and the median postoperative stay was 7.7 days (range 3.4–32.6 days). All patients (except the one who was asymptomatic before the operation) had resolution of the respiratory or gastrointestinal symptoms.

The median follow-up was 23 months (range 4–43 months). During the follow-up period, no patient had residual respiratory or gastrointestinal symptoms. All patients underwent at least 1 postoperative echocardiography and the results were satisfactory. A postoperative CT scan was performed in 3 patients, all of which showed patent LSCA–LCA anastomosis (Fig. 2).

Figure 2:

Postoperative computed tomographic image. The LSCA was anastomosed to the LCA. The asterisk shows where the Kommerell diverticulum was located before the resection. LCA: left carotid artery; LSCA: left subclavian artery.

DISCUSSION

The right-sided aortic arch with aberrant LSCA can be associated with Kommerell diverticulum. It is an embryological remnant of the dorsal left fourth aortic arch. If left untreated, a Kommerell diverticulum can enlarge and independently compress the trachea and the oesophagus. Backer et al. [3] reported in 2002 that a number of patients who underwent simple division of the ligamentum arteriosum had recurrent symptoms postoperatively, and subsequent resection of the Kommerell diverticulum with translocation of LSCA completely relieved the residual symptoms. This technique, including ligamentum division, diverticulum resection and LSCA translocation at the initial operation, has been advocated by Backer et al. [6], and their subsequent studies confirmed excellent surgical results.

In addition to the complete relief of the compression, another reason to resect the Kommerell diverticulum is that it can be a potential source of aneurysm formation or aortic dissection [8]. Kim et al. [9] reported that medial degeneration was noted on pathological examination of the Kommerell diverticulum and aortic specimens in all patients from whom specimens were obtained. Luciano et al. [10] pointed out that medial necrosis could be seen in very young patients, the youngest <1 year old at the time of diverticulum resection. These findings provide further evidence for the more extensive operation in paediatric patients. Backer et al. [6] recommend resection of the Kommerell diverticulum and translocation of the LSCA when the diameter exceeds 1.5 times the size of the distal LSCA.

Concomitant intracardiac anomalies may present together with right-sided aortic arch, aberrant LSCA and Kommerell diverticulum. Currently, there is no guideline for the treatment of this constellation of congenital abnormalities. Shinkawa et al. [11] hypothesized that these patients might do better with a simple division of the ligamentum arteriosum and repair of intracardiac anomaly under CPB through a median sternotomy. However, no patients in their series underwent concomitant intracardiac repair. In this study, we found that resection of the Kommerell diverticulum and translocation of the aberrant LSCA can be safely performed in addition to the division of ligamentum and intracardiac repair. There were no postoperative complications such as residual compression symptoms, chylous effusion, nerve injury or neurological deficits. After accumulating initial experiences, we currently endorse an aggressive surgical strategy that once the diagnosis is confirmed (intracardiac anomaly requiring surgical repair, right-sided aortic arch, aberrant LSCA and Kommerell diverticulum), resection of the Kommerell diverticulum and translocation of the LSCA should be performed at the initial operation regardless of the size of the diverticulum or the compression symptoms.

Preoperative evaluation and diagnosis of this form of a vascular ring (right-sided aortic arch, aberrant LSCA and Kommerell diverticulum) are important. For very young paediatric patients, gastrointestinal symptoms (such as dysphagia and reflux) might not be obvious. Besides, some symptoms such as recurrent pulmonary infections might be ascribed to the concomitant intracardiac anomalies. In our series, all patients underwent a preoperative CT scan, which gave us clear images of the vascular structures and the trachea. It is worthy to note that 1 patient, who had no respiratory or gastrointestinal symptoms, was found to have a right-sided aortic arch and possible aberrant LSCA at the preoperative echocardiography. Further CT scan confirmed the diagnosis of aberrant LSCA and large Kommerell diverticulum, which required surgical intervention by our protocol. Thus, we recommend CT scan (or magnetic resonance imaging) not only for symptomatic patients but also for asymptomatic patients who were found to have suspicious aberrant subclavian arteries at the echocardiography.

This study was limited by its retrospective and observational nature. The sample size was small and the follow-up period was relatively short. In addition, we were unable to find a suitable control group. Future studies with comparison and long-term follow-up are necessary.

CONCLUSION

In conclusion, translocation of the aberrant LSCA and resection of the Kommerell diverticulum can be safely performed during the concomitant repair of intracardiac anomalies in paediatric patients. This approach could eliminate residual respiratory and gastrointestinal symptoms, and prevent reintervention in the future.

Conflict of interest: none declared.

AUTHOR CONTRIBUTIONS

Kang An: Conceptualization; Data curation; Formal analysis; Investigation; Writing—original draft. Shoujun Li: Data curation; Funding acquisition; Investigation; Supervision; Visualization. Jun Yan: Conceptualization; Resources; Writing—review & editing. Xu Wang: Conceptualization; Methodology; Writing—review & editing. Zhongdong Hua: Conceptualization; Supervision; Validation; Visualization.

REVIEWER INFORMATION

Interactive CardioVascular and Thoracic Surgery thanks Lars Nolke, Yoshihiro Oshima and the other, anonymous reviewer(s) for their contribution to the peer review process of this article.

ABBREVIATIONS

CPB

Cardiopulmonary bypass

CT

Computed tomography

LCA

Left carotid artery

LSCA

Left subclavian artery

VSD

Ventricular septal defect