Bronchoscopic Management of Central Airway Obstruction in Children after Heart Surgery

Abstract

Objectives

Central airway stenosis following congenital heart malformation surgery is a rare but significant cause of postoperative weaning failure. In selected cases, bronchoscopic interventions are effective treatment options for managing these kind of airway obstructions and achieving successful weaning.

Methods

The data of six pediatric patients who were unable to be weaned from mechanical ventilation due to central airway obstruction following congenital heart malformation surgery were retrospectively analyzed. Rigid and flexible bronchoscopies were performed under general anesthesia for six patients.

Results

Six patients (4 males and 2 females; age range: 4 months to 6 years) with an airway obstruction after surgery due to congenital heart malformations included the study. Three patients had an obstruction of the left main bronchus, two of the right main bronchus, and one of bilateral main bronchus. Balloon dilatation was applied to one patient, mechanical dilatation was applied to three patients, and airway stent was applied to two patients. Two of six patients died from nonprocedural causes (acute respiratory distress syndrome due to pneumonia and cardiac arrest due to severe heart failure) and four patients were weaned successfully from mechanical ventilation and they were still alive during the follow-up period. No procedural-related mortality was seen in the study population. In one patient, stent placement could not be performed due to desaturation and hemodynamic instability during the procedure, and in another patient, granulation tissue developed due to a covered metallic stent, and the metallic stent was removed and replaced with a biodegradable stent.

Conclusion

In selected cases, bronchoscopic interventions offer efficient approach to managing airway obstructions due to congenital heart malformation surgery.

 

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Keywords

airway (includes related subject matter) - congenital heart disease - CHD - pediatric - bronchial disease (includes injury, stenosis, tumor, etc.)

Introduction

Central airway obstructions that develop after congenital heart malformation surgery make the management of these children more complex and challenging. This newly developed central airway obstruction was likely related to prolonged intubation and mechanical ventilation support due to extended surgery or changes in the airway anatomy caused by the surgery.[1] [2] These children may require varying durations of ventilation. In pediatric intensive care units, weaning failure rates range from 2.7 to 22%, with a specific rate of 19% observed in children undergoing cardiac surgery for congenital heart anomalies.[3] [4] [5] [6] [7] Significant airway obstruction after complex congenital heart defects presents a critical clinical challenge, leading to morbidity and mortality mainly due to weaning failure and its associated complications. Bronchoscopic interventions, with or without airway stenting, are an effective option for patients with airway obstruction contributing to weaning failure. This retrospective study aims to evaluate the effectiveness of endobronchial treatments in pediatric patients with significant airway obstruction following congenital heart surgery.

 

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Methods

Study Design and Patient Selection

In this retrospective study, the data of six pediatric patients who presented to the interventional pulmonology unit of a tertiary hospital between August 2012 and June 2016 with central airway obstruction following congenital heart malformation surgery were retrospectively analyzed. All patients had central airway obstruction following congenital heart malformation surgery, preventing successful weaning from mechanical ventilation and requiring invasive mechanical ventilatory support. Two patients were on mechanical ventilator support via a tracheostomy cannula (Patients 2 and 4), whereas four patients were supported through an endotracheal tube.

Patients informed written consent for the publication of the study data was obtained from legal parents. The diagnosis of underlying cardiac disease, type of cardiac surgery, weaning failure rate (weaning from mechanical ventilation), length of intubation, type of airway obstruction, and appropriate endobronchial treatment for each case were noted.

 

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Bronchoscopic Techniques

Flexible bronchoscopy (Karl Storz, pediatric bronchoscope, Tuttlingen, Germany) was initially performed to ascertain the type, location, and severity of the stenosis. This procedure was conducted by inserting the bronchoscope through the endotracheal tube while the patients were under mechanical ventilator support. Subsequently, all six patients underwent intubation with a rigid bronchoscope (Efer Endoscopy, La Ciotat, France). The stenotic area was then dilated using the rigid bronchoscope. Balloon dilation was performed with a Fogarty balloon catheter if needed. The Dumon (Novatech, Pont-de-Buis-lès-Quimerch, France) Y stent, Silmet-coated metallic stent (Novatech), and custom-made biodegradable stents (Ella-CS, Hradec Kralove, Czech Republic), crafted from woven polydioxanone monofilament, were inserted using suitable equipment, as detailed in existing literature.[8] [9]

 

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Data Collection, Statistical Analysis, and Measurements

Clinical and radiological data were gathered from the hospital's electronic database, chart reviews, and radiological systems. The applied endobronchial treatments, success rate of weaning, incidence of weaning failure, and occurrence of complications were recorded. Weaning failure was defined as the need for reintroducing ventilatory support within 24 to 72 hours following planned weaning from mechanical ventilation.[10]

 

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Results

Six patients (4 males and 2 females; age range: 4 months–6 years) with an airway obstruction after surgical repair due to congenital heart disease were included in the study. All patients were dependent on invasive mechanical ventilator support (Patients 2 and 4 via tracheostomy cannula, others via endotracheal tube) and unable to be weaned due to airway obstruction following surgery. Characteristics of each case are given in detail in [Table 1]. Three patients had an obstruction in the left main bronchus, two in the right main bronchus, and one in the bilateral main bronchus. One patient had bronchomalacia (Patient 2). Balloon dilatation was successfully performed in Patient 1, who had an obstruction in the right main bronchus ([Fig. 1]). After discussion with an experienced radiologist who measured the diameters of airways radiologically 8 × 4 × 4 mm diameter, Y stent was planned to apply for Patient 2 who had an obstruction in the bilateral main bronchus. However, during the placement of Y stent, the patient became desaturated and hemodynamically unstable due to severely compromised cardiac and respiratory function and we could not apply Y stent for Patient 2. Initially, a straight silicone stent with a 12 mm diameter was inserted into Patient 3, who had a nearly complete obstruction of the left main bronchus. However, due to insufficient radial force to maintain patency of the left bronchus, the stent was subsequently removed ([Fig. 2]) and a fully covered metallic stent of 12 mm (12 × 30 mm Silmet, Novatech France) was applied successfully. However, due to obstruction at the entrance of the left main bronchus due to the granulation tissue, the covered metallic stent was removed and a biodegradable stent was applied ([Fig. 2]). Absorption time for the biodegradable stent in Patient 3 was 9 weeks. During the subsequent control bronchoscopy at the same interval, it was noted that the stent had dissolved, ensuring the patency of the lumen. Mechanical dilatation using an appropriate diameter rigid tube was performed for Patients 4 to 6. In Patient 4, a 50% narrowing was observed at the entrance of the left main bronchus due to external compression, and dense mucoid secretions were seen distal to the bronchus. Mechanical dilatation was applied to this area, and the distal secretions were cleared. After dilatation, 60% lumen patency was achieved. However, despite achieving optimal airway patency after dilatation, Patient 4 could not be weaned due to severe heart failure and resulting hemodynamic instability. In Patient 5, a 60% narrowing was observed at the entrance of the right main bronchus due to anterior wall compression and collapse, and secretions were noted distal to the bronchus. Mechanical dilatation was performed in this area, and the distal secretions were removed. Following the dilatation, 50% lumen patency was achieved. In Patient 6, approximately 2 cm proximal to the main carina in the distal trachea, a 1-cm segment of superficial granulation tissue on the mucosa was observed, accompanied by a 40% lumen narrowing due to external compression. Mechanical dilatation was applied to this area, and 70% lumen patency was achieved. Patients 5 and 6 were successfully weaned from mechanical ventilation following the procedure. Follow-up period was between 18 days and 20 months. Two of six patients died from nonprocedural causes (Patient 2, at age of 9 months died from acute respiratory distress syndrome due to pneumonia, and Patient 4, at age of 7 months died from cardiac arrest due to severe heart failure) and four patients were weaned successfully from mechanical ventilation, and they were still alive during the follow-up period. No procedure-related mortalities were seen in the study population. In one patient, stent placement could not be performed due to desaturation and hemodynamic instability during the procedure. In another patient, granulation tissue developed due to a covered metallic stent, and the metallic stent was removed and replaced with a biodegradable stent.

Table 1 Characteristics of patients

Patient	Age (mo)/ gender	Underlying cardiac disease	Cardiac procedure	Type and localization of airway obstruction	Endobronchial treatment	Total IT before EBT (d)	Number of WF	Extubation time after EBT (d)	Follow-up till age (duration time)
1	6 mo/M	VSD, PDA, AS, PS	VSD repair and subvalvular resection	IS + SR/RMB	Balloon dilatation	4 d	1	1 d	3 y (20 mo)
2	9 mo/M	Pulmonary atresia	Shunt application	EC and BM/ RMB + LMB	Y-stent	112 d	4	Died (ARDS due to pneumonia)	1 y (18 d)
3	72 mo/M	Operated TGA	LVAD application	EC/LMB	Silicone stent and covered metallic stent followed by bioabsorbable stent	21 d	2	2 d	8 y (12 mo)
4	7 mo/F	Aortic interruption, tricuspid atresia, RV hypoplasia	Glenn-type shunt application PDA repair	EC + SR/LMB	Mechanical dilatation	34 d	3	Died (cardiac arrest due to SHF)	8 mo (34 d)
5	4 mo/F	Complete AVSD Wide premium ASD, wide-inlet VSD, PHT	Repair of complete AV canal with double patch technique	EC + SR/RMB	Mechanical dilatation	17 d	3	3 d	1 y (2 mo)
6	48 mo/M	VSD, PA NCPA, HrPA	Shunt application	EC + IS + SR/distal trachea	Mechanical dilatation	11 d	2	1 d	6 y (5 mo)

Abbreviations: ARDS, acute respiratory distress syndrome; AS, aortic stenosis; ASD, atrial septal defect; AV, atrioventricular; AVSD, atrioventricular septal defect; BM, bronchomalacia; EBT, endobronchial treatment; EC, external compression; HrPA, hypoplastic right pulmonary artery; IS, intrinsic stenosis; IT, intubation time; LMB, left main bronchus; LVAD, left ventricular-assist device; NCPA, nonconfluent pulmonary artery; PDA, patent ductus arteriosus; PS, pulmonary stenosis; PHT, pulmonary hypertension; RMB, right main bronchus; RV, right ventricular; SR, secretion retention; SVH, severe heart failure; TGA, transposition of great arteries; VSD, ventricular septal defect; WF, weaning failure.

Fig. 1 (A) Right main bronchus obstruction before endobronchial treatment in Patient 1. (B) Balloon dilation application to the right main bronchus. (C, D) Chest X-ray of the patient before and after dilation procedure.

Fig. 2 (A) The left main bronchus of Patient 3 had a nearly total obstruction. (B) The radial force of silicone 12-mm straight stent may not have been sufficient to keep the left main bronchus open. (C). Obstruction in the entrance of the left main bronchus due to covered metallic stent. (D) A biodegradable stent has been inserted after removal of covered metallic stent. (E) Chest X-ray of Patient 3 before biodegradable stent insertion. (F) Chest X-ray of Patient 3 after biodegradable stent insertion.

 

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Discussion

There is a significant association between weaning failure and airway obstruction in children with congenital heart disease. Evaluating the airway after weaning failure in pediatric patients who have undergone heart surgery or interventional catheterization often reveals airway narrowing. This narrowing may result from direct external compression of the airways, prolonged ventilatory support, postintubation laryngeal stenosis, and vocal cord paresis due to injury to the recurrent nerve or secondary to fluid overload with interstitial edema or combination of these factors.[7] [11] [12] Infants and young children are particularly susceptible to extrinsic compression due to their proportionally smaller airway dimensions.[12] [13] Additionally, atelectasis and air trapping are common in infants because of anatomical features and vulnerability to airway collapse. This population also has high peripheral airway resistance, increasing the risk of airway closure.

Bronchoscopic evaluations in pediatric patients postcardiac surgery for congenital heart defects have shown a 50% prevalence of airway narrowing, although its predictive value for subsequent weaning failure is poor. Conversely, other studies have demonstrated a link between weaning failure and airway narrowing.[12] [14] [15]

For diagnostic and therapeutic purposes in children with vascular compression of the airway, a combination of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) is usually essential.[16] However, MDCT and MRI have limitations in directly visualizing obliterated vascular segments such as the ligamentum arteriosum or an atretic aortic arch.[16] [17] Additionally, differentiating between dynamic and static narrowing using these imaging techniques is restricted, which is crucial in cases of prolonged airway compression resulting in secondary malacia.[18] [19] Thus, bronchoscopy remains the most effective technique, particularly for evaluating secondary malacia.

In this study, all patients underwent MDCT and bronchoscopy, with one patient diagnosed with bronchomalacia. While evaluating bronchomalacia in an intubated patient can be challenging, observing airway movements during inspiration and expiration under mechanical ventilator support can provide valuable information.

A limited number of studies have demonstrated the safety and efficacy of endobronchial treatments in managing airway obstructions in children following cardiac surgery for congenital heart defects.[1] Secretion clearance, balloon dilatation, mechanical dilatation, and stent placement are the most commonly used therapeutic bronchoscopy procedures in the management of these patients.

Airway stents are one of the most commonly used endobronchial treatment methods in cases where the lumen of the central airways becomes narrowed due to the loss of supportive tissue or external compression. In pediatric patients who develop central airway stenosis following congenital heart defect surgery, stent placement presents additional challenges beyond the general complications of stenting. The first challenge is that these patients have limited cardiac and respiratory reserves, increasing the risk of complications during stent placement. For instance, in Patient 2, due to severely compromised cardiac and respiratory function, the patient became desaturated and hemodynamically unstable before we could even place the stent, ultimately making the procedure impossible.

The second major challenge is selecting the appropriate stent for these patients. Measuring the correct stent size and diameter is significantly more difficult in pediatric cases compared with adults. After selecting the appropriate stent size, another issue is whether the stent has sufficient radial force to maintain airway patency. Self-expanding stents offer greater flexibility compared with balloon-expandable stents.[16] [20] The consequences of vascular erosion depend on factors such as sizing, the radial force exerted by the stent, compromised tissue blood flow, and the integrity of the airway wall. In our study, the use of a fully covered metallic stent followed by the placement of a bioabsorbable stent proved successful in Patient 3, who had an obstruction in the left main bronchus. Silicone stents exhibit minimal stress levels, possibly due to the weaker contact between the stent and the main bronchus, which could account for their tendency to migrate.[21] [22] Choosing the right stent relies on several factors, including the patient's condition, characteristics of the airway stenosis, the physician's expertise, and the availability of equipment.[23] In Patient 3, the collapse of the silicone stent was likely due to a combination of cardiomegaly, enlarged vessels, volume/pressure effects of a left ventricular assist device, and the radial forces of the stent rather than its diameter. Therefore, a covered metallic stent was applied to alleviate the obstruction and collapse of the airway, followed by the placement of a bioabsorbable stent.

Caution should be exercised when considering the use of self-expandable metallic stents in patients with benign airway disease, as there are risks of complications related to the stent and challenges associated with its removal. Nonetheless, recent findings indicate that third-generation self-expandable metallic stents are a viable and safe option for treating complex benign airway stenosis. However, it is noteworthy that complications necessitating stent removal such as granuloma formations, erosions of a nearby vascular structure, or infections are common in such cases.[24]

On the other hand, bioabsorbable stents can be used successfully in children with significant airway obstruction following repair of a complex congenital heart defect, depending on the patient's dynamic airway remodeling after surgery. This area, however, requires further research. The SX-Ella Biodegradable stent, made from woven polydioxanone monofilament, is designed for airway applications, maintaining integrity, and radial force for 6 to 8 weeks.[8] [9] [25] In Patient 3 from our study, the absorption time was 9 weeks without complications. Introducing the biodegradable stent in Patient 3 aimed to provide a minimally invasive temporary solution, potentially reducing the need for further interventions and limiting complications associated with subsequent stenting applications. While biodegradable stents may offer an alternative to metallic or silicone stents for airway collapse or external compression in children, the risk of large decaying fragments, particularly in small-sized airways, is a concern, as reported in infants with tracheomalacia and tracheobronchomalacia.[26] However, we did not observe this complication in our patient, and the use of the biodegradable stent may have reduced the number of further interventions and limited potential complications.

Balloon dilatation was successfully applied in one of our patients. Although it may provide only a slight increase in airway diameter depending on the severity and location of the stenosis, balloon dilatation can reduce airway resistance and help relieve wall stress at the narrowed segment.[20]

Mechanical dilatation and secretion clearance were performed on patients numbered 4 to 6. In these patients, airway narrowing caused by compression from cardiovascular structures or cardiac surgery cannot be fully resolved by mechanical dilatation alone. However, pediatric patients who have undergone congenital heart surgery generally have low cardiorespiratory reserves. In such cases, even a slight improvement in airway diameter combined with secretion clearance can reduce airway resistance and improve respiratory mechanics. Although mechanical dilatation and secretion removal in Patients 5 and 6 did not achieve perfect airway patency, these interventions helped surpass the critical threshold necessary for successful extubation. Therefore, they contributed positively to the extubation process. On the other hand, despite achieving ∼60% airway patency after dilatation in Patient 4, extubation could not be performed due to advanced heart failure and hemodynamic instability.

One patient in our study population (Patient 2) was diagnosed with bronchomalacia, confirmed through bronchoscopy. This patient was clinically unstable, and oxygen desaturation occurred during Y stent placement, likely due to the patient's instability. Bronchomalacia is definitively diagnosed via bronchoscopy, although MDCT, capable of acquiring end-expiratory and end-inspiratory images, may enhance noninvasive diagnostic accuracy for this condition.[27] [28]

This study is among the few in the literature evaluating bronchoscopic management of airway obstructions following congenital heart malformation surgery. These cases are rare, challenging to manage, and typically concentrated in specialized centers due to their complexity. Consequently, our study included a small number of cases. Additionally, we lacked a comparison group, such as patients undergoing surgical correction of congenital heart malformations during childhood or those with central airway obstructions causing difficult weaning that were managed surgically. Therefore, we were unable to compare safety, effectiveness, and cost outcomes between groups.

In conclusion, managing central airway obstruction following congenital heart malformation surgery is highly challenging. In these patients experiencing weaning failure due to central airway obstruction, interventional bronchoscopic techniques can serve as an effective treatment option.

 

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Conflict of Interest

None declared.

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Publication History

Received: 25 October 2024

Accepted: 10 June 2025

Article published online:
27 June 2025