A Lethal Late Complication: Aortoesophageal Fistula after TEVAR

Abstract

Thoracic endovascular aortic repair (TEVAR) has been performed in the treatment of thoracic aortic disease since the mid-1990s. Complications associated with TEVAR are increasing rapidly due to its widespread use. One of these complications is late lethal aortoesophageal fistula (AEF). The aim of this study was to describe the diagnosis of AEF in a 64-year-old woman 8 months after TEVAR. The AEF was diagnosed on a computed tomography angiography with oral and intravenous contrast. The patient underwent open surgical repair and died of sepsis 12 days after surgery.

Thoracic endovascular aortic repair (TEVAR) is the procedure of choice for thoracic aortic disease, especially in high-risk patients with comorbidities. ¹ With the widespread use of TEVAR procedures, the variety and frequency of complications are increasing. Examples of these complications include endoleak, paraplegia, stroke, stent graft infection, aortoesophageal fistula (AEF), and aortobronchial fistula (ABF). ^{2 3} The incidence of AEF after TEVAR is known to be between 1.5 and 1.9%. ^{1 3 4} Although the diagnosis of AEF after TEVAR is usually confirmed by endoscopy, it can also be confirmed by computed tomography angiography (CTA). Treatment options include endovascular and open surgical repair. The aim of this study was to describe the use of oral contrast during CTA to aid in the diagnosis and report the results of a case treated by open surgical repair.

Case Report

Video 1 Suspiciouss infected areas and air densities around the thoracic endovascular aortic repair graft.

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Video 2 Visualization of oral contrast material around the thoracic endovascular aortic repair graft and clarification of the diagnosis of aortoesophageal fistula.

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A 64-year-old woman who underwent TEVAR operation (Medtronic, Valiant Thoracic Stent Graft, 38 × 38 × 200mm, proximal landing zone 3) for type 3 dissection 8 months ago presented with complaints of extreme fatigue and weakness for the last 2 weeks. At the time of admission, blood pressure was 124/73 mm Hg, pulse rate was 82 and in sinus rhythm, oxygen saturation was 97, and there was no fever. The laboratory findings of the patient at the time of presentation are shown in Table 1 .

Table 1. Preoperative laboratory findings.

Findings	Patient's values (References)
Leukocyte	5.96 10 3 /µL (4.5–11)
Hemoglobin	7.3 g/dL (11.7–16.1)
Hematocrit	24.8% (35–47)
Platelets	129 10 3 /µL (150–450)
C-reactive protein	47.19 mg/L (0–5)
ALT	14 U/L (<31)
AST	19 U/L (<34)
ALP	60 U/L (35–104)
GGT	10 U/L (<38)
Urea	26 mg/dL (10–50)
Creatinine	0.69 mg/dL (0.6–1.1)

Abbreviations: ALP, alkaline phosphatase; ALT, alanine transaminase; AST, aspartate aminotransferase; GGT, gamma-glutamyl transferase.

CTA without oral contrast was performed for further investigation because of anemia and elevated C-reactive protein. CTA revealed air densities around the TEVAR graft consistent with infection ( Fig. 1 , Video 1 ). Massive hematemesis and melena developed in the patient who was being followed up in intensive care unit. A complete blood count resulted in a hemoglobin of 5.8 g/dL and a hematocrit of 19.5%. A CTA was performed this time with oral contrast to confirm the suspicion of an AEF ( Fig. 2 , Video 2 ). The diagnosis was confirmed when oral contrast was seen around the TEVAR graft on CTA. Open surgical repair was completed under cardiopulmonary bypass. AEF was observed and the infected TEVAR graft was excised ( Fig. 3 ). Diffuse adhesions and stent graft erosion were observed at the fistula site. A Dacron graft was anastomosed to the excised TEVAR graft site. The esophagus was repaired by the general surgery team and a Witzel jejunostomy was performed. Corynebacterium argentoratense , Prevotella denticola , and Streptococcus anginosus growth were observed in the excised TEVAR graft cultures. The patient's antibiotics were changed to meropenem and teicoplanin based on the results of culture sensitivities. CTA performed on the 12th postoperative day showed that the thoracic aorta graft and esophagus were intact. The patient died of sepsis on postoperative day 14.

Fig. 1.

Suspicious infected areas and air densities around the thoracic endovascular aortic repair graft.

Fig. 2.

Visualization of oral contrast material around the thoracic endovascular aortic repair graft and clarification of the diagnosis of aortoesophageal fistula.

Fig. 3.

( A ) Intraoperative aortoesophageal fistula image—esophagus. ( B ) Excised infected thoracic endovascular aortic repair graft.

Discussion

Arterial phase CTA and endoscopy are commonly used to diagnose AEF. In most cases, the appearance of air bubbles around the TEVAR graft and the visualization of AEF on endoscopy are sufficient for diagnosis. ^{5 6} In cases where the diagnosis is uncertain, performing CTA with oral contrast may help to clarify the diagnosis. Observation of contrast around the thoracic aortic graft is diagnostic for AEF.

There are several hypotheses for the pathogenesis of AEF. The basic physiopathology is the formation of a fistula as a result of erosion of the esophageal or aortic wall for any reason. These causes range from swallowing fish bones to aortic infections. ^{4 7} The surgical plan should be decided on a multidisciplinary basis according to the general condition of the patient, the type of fistula formation, and the presence or absence of signs of infection in the fistula site.

Aortic erosion after TEVAR should be analyzed separately. The rigid structure of stent graft materials may cause erosion of the aortic wall even in the absence of infection. ⁶ Emergency TEVARs require evaluation for the degree of perioperative aseptic technique and detailed evaluation for the presence of aortic rupture. If there is a rupture prior to TEVAR, there is already an inflammatory background. This inflammation may provide a suitable basis for fistula formation. If adequate asepsis/antisepsis could not be achieved preoperatively, the use of broad-spectrum antibiotics in the perioperative period may be considered to prevent infectious processes.

Another issue to consider is the size of the TEVAR graft. To avoid endoleak after TEVAR graft implantation, a TEVAR graft 10% larger than the aortic diameter is generally used. Increasing this oversizing rate may lead to aortic wall damage and fistula formation. ⁶

Patients may present with symptoms ranging from nonspecific symptoms like fever and fatigue to hemorrhagic shock. CTA may be reperformed if AEF is suspected, if fatigue persists on repeat admissions, and if anemia persists on complete blood count.

A review of the literature shows that medical treatment has not been successful in the treatment of AEF, but it is not yet clear how surgical or endovascular treatment should be performed. ⁴ According to the European Registry of Endovascular Aortic Repair Complications, the highest mortality rate at 1-year follow-up was 100% with conservative treatment. In contrast, the best results are found with aggressive surgical treatment including radical esophagectomy and aortic replacement. ³ In this study, the aortic graft was first excised, and an open surgical repair was performed as an anatomical bypass, followed by an esophageal repair in a simultaneous operation. Although there was no postoperative drainage and the aorta was shown to be intact on CTA, the patient died on postoperative day 14 due to sepsis. Further studies on the management of AEF are needed.

Conclusion

AEF is a late and lethal complication after TEVAR. When the presence of AEF is suspected, the diagnosis can be clarified by arterial phase CTA, endoscopy, or oral contrast CTA. Although open surgical treatment is usually performed, further studies are needed to improve the results. It should be kept in mind that most of the patients have an infective background and sepsis should be prevented with broad spectrum antibiotherapy in the perioperative period.