Successful endoscopic clipping management of a left atrioesophageal fistula after atrial fibrillation catheter ablation: A case report of a young male patient

Abstract

Atrioesophageal fistula (AEF) is a rare and serious complication of atrial fibrillation (AF) ablation, forming a connection between the atrium and esophagus. A systematic treatment approach for AEF has not been established to date. Herein, we report the case of a young male patient with left AEF after AF catheter ablation, which was successfully treated with the Over-the-Scope Clip (Ovesco Endoscopy AG, Tübingen, Germany) and conservative management. Despite having a double-orifice mitral valve and tricuspid valve, the patient had no symptoms or valve disease. The patient was readmitted three weeks after the procedure owing to fever, hematemesis, consciousness disturbance, hemiplegia, and systemic convulsions. Indigenous bacteria in the oral cavity were detected in blood culture. Magnetic resonance imaging of the brain showed multiple cerebral infarctions. Chest computed tomography showed mediastinal air, suggesting an AEF diagnosis. Subsequently, an endoscopic closure using the Over-the-Scope Clip was performed, leading to a successful recovery and patient discharge on day 87 after admission. This is the first case report of a successful management of AEF after radiofrequency ablation using the Over-the-Scope Clip system. Although surgery is the main treatment for AEFs, we performed nonsurgical management using the clip, demonstrating a potential treatment option for AEF.

Learning objective

Surgical intervention is usually superior to endoscopic intervention and conservative management for treatment of atrioesophageal fistula. To the best of our knowledge, this is the first case to be successfully managed by endoscopic clipping and conservative management.

Introduction

Catheter ablation is increasingly being used worldwide to treat patients with atrial fibrillation (AF); however, it carries a risk of atrioesophageal fistula (AEF), a rare but serious complication. Although AEF occurs in only 0.03%–0.11% of patients undergoing ablation, it is often fatal, with a mortality rate of 70%–80% [1]. Generally, prompt surgical repair is essential for survival. However, a systematic therapeutic approach to AEFs has not been established to date. Herein, we report the successful treatment of an AEF after AF ablation without major surgery, i.e. by endoscopic closure using the Over-the-Scope Clip (OTSC; Ovesco Endoscopy AG, Tübingen, Germany).

Case report

A 20-year-old man was diagnosed with paroxysmal AF at age 19 years, which then progressed into persistent AF. The patient also had a history of double-orifice mitral and tricuspid valves, without consequential valvular disease, and reflux esophagitis, which was treated with esomeprazole. Although the patient had no notable symptoms of AF, we performed AF ablation considering his age and risk factors after the onset of chronic AF. The patient underwent encircling circumferential pulmonary vein isolation, left atrial posterior isolation, and cavotricuspid isthmus ablation using EnSite Precision™ (Abbott, St Paul, MN, USA) and a 3.5-mm irrigated tip TactiCath™ ablation catheter (Abbott). Ablation was performed at 30–35 W, guided by a lesion-size-index of 4.0–5.0 on the left atrium (LA) posterior wall and of ≧5.5 on the anterior wall and roof (Fig. 1a). During the procedure, contact force data during the procedure were as follows. At the inferior half of the LA posterior wall: median of max contact was 27.5 g; range of max contact, 17–67 g; median of average contact, 17 g; and range of average contact, 9–27 g. At points where the esophageal temperature was higher than 40 °C: median of max contact was 25 g; range of max contact, 15–36 g; median of average contact, 15 g; and range of average contact, 6–20 g. The wave of contact force was greater than 30 g at three points (No. 30, No. 67, and No. 69: Fig. 1b), and the maximum difference was 67 g (No. 30). The intraluminal esophageal temperature was continuously monitored using a temperature probe, and radiofrequency (RF) was terminated immediately at a temperature of >40 °C. The procedure was performed under general anesthesia, i.e., using i-gel® (Intersurgical Ltd., Wokingham, UK) and a ventilator for airway management, thiopental and dexmedetomidine for sedation, fentanyl for analgesia, and rocuronium for muscle relaxation. The patient received anticoagulants (edoxaban) before and immediately following ablation, and dabigatran on the operation day. Following the surgery, the patient was discharged uneventfully in sinus rhythm, but was readmitted 21 days later with a sudden onset of fever (40 °C), hematemesis, disturbed consciousness, hemiplegia, and systemic convulsions. The patient was admitted to the intensive care unit and underwent intubation and ventilation, and intravenous antibiotic and anticonvulsant therapy. Streptococcus oralis was detected in blood cultures. Magnetic resonance imaging revealed multiple areas of acute cerebral infarction (Fig. 2d). Chest computed tomography (CT) angiography revealed focal collection of air in the mediastinum located distant from the right aspect of the esophagus, posterior to the right inferior pulmonary vein–LA junction, indicating an AEF (Fig. 2a, b, c). Transthoracic echocardiography revealed airflow into the LA induced by sputum suction, suggesting a connection between the LA and esophagus. Gastroesophageal endoscopy revealed a pinhole-like lesion in the esophagus (Fig. 3a), confirming an AEF diagnosis. After discussion with experts, we selected endoscopic closure of AEF using the OTSC and conservative treatment (Fig. 3b); emergency surgery was always available in case of deterioration of the condition. We performed diagnostic and therapeutic endoscopic procedures through two phases. After the procedure, the patient became afebrile, with improved convulsion symptoms and laboratory test results. Chest CT performed to re-evaluate the AEF showed no pneumomediastinum. However, two weeks after admission, a cerebral abscess was detected, diagnosed based on frequent apnea attacks, epilepsy waves in the electroencephalogram, and a ring-enhanced sign on head CT (Fig. 2e). Owing to his unstable breathing status, we temporarily performed tracheotomy. The cerebral abscess was treated with intravenous antibiotics. Two weeks after the diagnosis, the abscess had shrunk, and apnea symptoms and epilepsy waves had disappeared (Fig. 2f). Consequently, we withdrew the ventilator and closed the tracheotomy hole. Thereafter, the patient was rehabilitated until no daily life support was required. Neurological findings showed mild higher-order functional disability, which also improved. He was discharged 87 days after admission and had no signs of symptom recurrence at the 6-month follow-up.

Fig. 1.

Ablation summary.

(a) EnSite Precision™ (Abbott, St Paul, MN, USA) electroanatomic map of the left atrium. Point tags show ablation sites. Red tags indicate lesion size index (LSI) ≧5.5. Purple tags indicate LSI of 5.0–5.4. White tags indicate LSI <5.0. The blue ring shows the location of the fistula.

(b) There are three points where the wave of contact force is greater than 30 g. (No. 30, No. 67, and No. 69 in the figure) The maximum difference is 67 g (No. 30). These points coincide with the perforation site and may cause fistula formation.

Fig. 2.

Diagnosis of the atrioesophageal fistula and radiographic visualization of the cerebral complications. (a) (b) (c) Computed tomography angiogram of the chest; the blue arrows show the location of mediastinal air and the fistula; the green triangles show the nasogastric tube, indicating the position of the esophagus. (d) Magnetic resonance imaging scans of the brain showing multiple areas of acute cerebral infarction (red arrows). (e) Computed tomography showing a ring enhanced sign, diagnosed as a cerebral abscess (red triangle). (f) After 2 weeks of intravenous antibiotics treatment, the cerebral abscess has shrunk (red triangle).

Fig. 3.

Endoscopic visualization of the atrioesophageal fistula before and after Over-the-Scope-Clip placement. (a) Gastroesophageal endoscopy showing a pinhole-like lesion (blue arrow) in the esophagus. (b) Endoscopic closure using the Over-the-Scope Clip is performed.

Discussion

AEF can manifest 2–4 weeks after catheter ablation, and its typical symptoms include fever, chest pain, gastrointestinal bleeding, and neurological disorders, such as stroke, hemiparesis, and consciousness disturbance. Chest CT is useful for early diagnosis, which can detect abnormalities such as air in the mediastinum, LA, and outside of the esophagus, present in most AEF cases [2]. In our case, these symptoms appeared three weeks after ablation, and chest CT revealed air in the mediastinum. Oral bacteria found in blood cultures supported a diagnosis of AEF. Endoscopy should be avoided when an AEF is suspected to avoid increased esophageal pressure that may lead to potentially fatal aggravation of the fistula and air embolization. However, insufflation using CO2 instead of air helps reduce risks and has been adopted by some members of the writing group developing consensus statements [3]. We performed an endoscopy using CO₂ because we assessed an accurate pathological diagnosis and ensured the possibility of conversion to surgical repair. Although the exact mechanism of AEF is not fully understood, possible mechanisms of injury include direct thermal injury, acid reflux worsened or caused by ablation, infection from the lumen, and ischemic injury due to thermal occlusion of the end arterioles [4]. Appearance of AEF symptoms weeks later suggests that changes occurring later after AF ablation are more significant in forming AEF, than immediate thermal injuries. In this case, the LA perforation point was located posterior to the right inferior pulmonary vein, which was distant from the right aspect of the esophagus. Considering the air mixing into the LA, AEF was certainly formed, fistulizing from the esophagus to the mediastinum and the mediastinum to the LA in the post-ablation time course mentioned above. Regarding the process of AEF formation, endocardial catheter ablation may weaken both the posterior LA wall and the anterior esophageal walls; however, the esophageal wall becomes predominantly damaged, forming a fistula from the esophagus toward the atrium. Ablation lesion growth frequently progresses from the epicardium to endocardium in thin-walled tissue, as demonstrated in vivo in a dog model. This phenomenon likely occurs because of the endocardial cooling by catheter irrigation and circulating blood pool with subsequent delay in endocardial lesion formation [5]. Perforation of the LA without AEF has not been reported as a complication of AF ablation but esophageal perforation alone has [6]. Furthermore, cases have been reported in which esophageal-pericardial fistulas preceded AEF and were observed on chest CT with continuous ulceration of the esophagus, its continuation into the mediastinum and pericardial cavity, and finally perforation into the LA [7]. Multivariate analysis showed prompt surgical intervention provided the best chance of survival from AEFs, while nonsurgical and conservative treatments caused extremely high mortality rates. The overall mortality rate was 55%, which was significantly reduced in patients undergoing surgical repair (33%) compared with those undergoing endoscopic treatment (65%) and conservative management (97%) (adjusted odds ratio, 24.9; p < 0.01, compared with surgery) [2]. Since the patient had already developed cerebral infarction and had a high risk of cerebral bleeding under extracorporeal circulation during the operation, we selected endoscopic OTSC closure. Recently, the OTSC has been used to manage gastrointestinal bleeding, fistulas, anastomotic leakage, and perforation. Several case reports have described the effectiveness of endoscopically closing esophago-mediastinal fistulas, esophago-bronchial fistulas, and postoperative esophageal fistulas [8], [9]. However, we are the first to report the successful management of an AEF after catheter ablation using the OTSC.

Several reasons account for the treatment's success. First, the OTSC achieved excellent closure owing to its strong tissue gripping on all layers of the esophageal wall. Second, the bacteria found in the blood cultures were sensitive to antibiotics and the patient did not have serious infectious endocarditis. Third, AEF formation was expected to be relatively weak owing to the distance from the LA to esophagus. Multivariate analysis revealed the distance between the LA and esophagus was the only independent predictor [10]. Thus, using the OTSC should be considered with surgical repair.

No abnormal findings were observed during the patient's ablation procedure, and the operation went smoothly; nevertheless, an AEF was formed. The points where contact force was unstable coincided with the perforation site; thus, insufficient RF power reduction on the posterior wall and unstable contact force could have induced AEF formation.

In summary, we describe a case of successful treatment of AEF after AF ablation using endoscopic closure with the OTSC. Surgery is the mainstream treatment for AEFs; however, this case demonstrates that nonsurgical management using the OTSC is a potential treatment option for AEF closure. Therefore, clinicians should consider adopting this method to improve patient outcomes.

Declaration of competing interest

The authors declare that there is no conflict of interest.