Pulmonary Artery Stent Molding Using a Rigid Bronchoscope: A Case Report

Abstract

Bronchial compression following pulmonary artery endovascular stenting is a well-reported phenomenon with significant impact on the course of care for patients with congenital heart disease. There is a paucity of techniques described to either prevent or address this postprocedural complication. We report our successful experience with a novel technical variation—using a rigid bronchoscope—to address postpulmonary artery stent airway compression in a patient with single ventricle pathology.

Introduction

Airway compression following endovascular stenting in congenital heart disease was first described by Nuñez et al.¹ Patients postaortic arch repair are especially susceptible, given the altered infraarch geometry causing crowding of the left pulmonary artery and mainstem bronchus. Mild bronchial compression is often tolerated, but poststenting pulmonary symptoms occur in 20% with significant compression in 5% of patients.² Since its recognition, authors have attempted to minimize compression via intraoperative bronchoscopy and postplacement manipulation of stents.3, 4, 5 We have previously managed patients with stent-related compression with the technique described by Grohman et al³ but describe a novel variation utilizing rigid bronchoscopy.

Case report

A 3-year-old girl with congenital heart disease was referred for evaluation due to exertional dyspnea and cough following a left pulmonary artery angioplasty and stent placement.

She had a history of double-inlet left ventricle with restrictive atrial septal communication, coarctation of the aortic arch, transposition of the great arteries, ventricular septal defect, anomalous origin of the left anterior descending coronary artery, and a patent ductus arteriosus. She underwent a Norwood, 4-mm Blalock–Thomas–Taussig shunt, atrial septectomy, reconstruction of the pulmonary artery, and patent ductus arteriosus ligation at 7 days of life. She subsequently had a bidirectional Glenn with patch augmentation of the left pulmonary artery at 6 months and a left pulmonary artery angioplasty and stent implantation at 17 months of life with a Palmaz Genesis 2310 stent (Cordis) placed over a 7-mm balloon. Persistent cough and exertional dyspnea were later noted. A cardiac CT angiogram during pre-Fontan catheterization showed complete collapse of the left mainstem bronchus at the stent (Figure 1).

Figure 1.

Three-dimensional rendered anatomy of the aortic arch, mainstem bronchus, and vascular stent.

The patient was referred to our institution and taken for cardiac catheterization with flexible and rigid bronchoscopy on April 29, 2024. Rigid bronchoscopy was performed (Figure 2), the patient intubated, and flexible bronchoscopy was then performed. Pre-intervention fluroscopy of the stent was performed (Figure 3). Vascular access was obtained via 4F and 6F sheaths in the right femoral and internal jugular veins, respectively. Catheterization showed Glenn pressures of 12 mm Hg, systemic systolic pressures of 80 mm Hg, and left pulmonary artery pressures with no gradient across the stent (Figure 4). A thruway wire was passed, and a sterling 5 × 2 cm balloon was placed across the stent—although not inflated—for potential dilation. A 3.7-rigid ventilating bronchoscope was advanced into the area of stenosis, and placement relative to the stent was confirmed with fluoroscopy. Direct external compression was applied over the chest wall to mold the stent around the ventilating bronchoscope. The bronchoscope was removed, and flexible bronchoscopy was repeated, showing improved airway patency (Figure 5). The balloon was removed from the stent, stent conformation re-confirmed with fluoroscopy (Figures 3 and 6), and pressures were taken again, with no gradient across the stent (Figure 4). The patient was monitored in the cardiac intensive care unit and discharged on postoperative day 1.

Figure 2.

Initial bronchoscopy—compressed left mainstem bronchus.

Figure 3.

Postintervention bronchoscopy.

Figure 4.

Predeformation and postdeformation fluoroscopy of left pulmonary artery stent.

Figure 5.

Three-dimensional rotational fluoroscopy postdeformation.

Figure 6.

Preintervention and postintervention cardiac catheterization.

One month following, the patient had marked improvement in her cough and had not required her nebulizer since—compared with multiple times per week preoperatively. Repeat bronchoscopy at 5 months demonstrated improved bronchial patency (Figure 7), and by 6 months, the patient’s cough had resolved; she was able to be active without shortness of breath or activity limitation, and her mother reported 2 respiratory illnesses, which were markedly better tolerated than preprocedure. At Fontan completion, the patient is planned for left PA-plasty and surgical enlargement of the space beneath the arch as required.

Figure 7.

Five-month postintervention bronchoscopy.

Discussion

Bronchial compression is well-described following endovascular stenting in congenital heart disease—particularly in pulmonary artery stenosis, leading to left mainstem bronchus compression.2, 3, 4 Although stenting universally causes bronchial deformation, not all cases require intervention. Compression of <50% is often tolerated, and mild poststenting compression may not result in reduced lung volumes or altered spirometry.⁶ However, compression of at least 70% almost always requires intervention—in some cases, removal of pulmonary artery stents.^3,7

Preventative efforts have been described at the time of left pulmonary artery stent placement, including bronchoscopy to monitor compression and stent sizing, unique oval stents, and special techniques for deployment and dilation of the stent.^4,8,9 Regardless, poststent bronchial compression remains problematic. Balloon dilation of the compressed bronchus has been reported; however, this does not address the continued external compression.^3,10 After noting stent deformation during cardiopulmonary resuscitation, external deformation has been used to relieve airway compression secondary to stents.⁴ First described by Brown et al,⁴ placement of endoscopic balloons in the left mainstem bronchus and the stent with external pressure to the chest deformed the stent around the supported bronchus, resulting in improved lung ventilation without flow impairment through the stent. Subsequent techniques have foregone balloon inflation in the stent; however, a guidewire is generally placed in case of the development of a gradient across the stent.

In our center, we have managed 2 patients with compression of the left mainstem via external deformation of the stent utilizing an expanding balloon inside the bronchus. Ultimately, both achieved improved airway patency and no restriction of pulmonary blood flow; however, intraoperatively, difficulties were noted in maintaining the positioning of the airway balloon during the application of external pressure. To obviate that, we chose to provide directed intraluminal airway pressure with a rigid bronchoscope rather than a balloon as we could then apply a force vector anteriorly in addition to the external pressure. The largest rigid ventilating bronchoscope that could be placed with minimal trauma was used, allowing repeated deformations of the stent and repositioning of the airway instrumentation, similar to balloon use. As stenting is a temporizing measure, we anticipate definitive left pulmonary arterioplasty during Fontan completion and likely surgical enlargement of infra-arch space to accommodate the vasculature and airway—with further stent dilations or deformations only as symptomatically indicated.

The size of the patient is a limitation to this technique, as the airway must be able to accommodate a rigid bronchoscope—versus an expandable balloon. In our experience with extrinsic tracheobronchomalacia, the degree of compression is less limiting to the passage of a bronchoscope, given the malacic nature of the airway. However, care must be taken to limit trauma from rigid instruments. Although this is an uncommon problem seen in a subset of patients, we believe this modification is a useful addition in this difficult situation.

CRediT authorship contribution statement

Ethan Frank: Conceptualization, Writing – original draft, Writing – review & editing. Howaida El-Said: Conceptualization, Supervision, Writing – review & editing. Matthew Brigger: Conceptualization, Supervision, Writing – review & editing.

Declaration of competing interest

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.