Published online Sep 03, 2024.
https://doi.org/10.3349/ymj.2023.0552
Experiences of Surgical Approach for Aortoduodenal Fistula Repairs in Abdominal Aortic Aneurysm Patients
Abstract
Purpose
This study aimed to analyze the characteristics and outcomes of patients with an aortoduodenal fistula (ADF) who underwent surgical treatment at a single institution.
Materials and Methods
The data of patients diagnosed with ADF at the Yonsei University Gangnam Severance Hospital, South Korea, between 2019 and 2022 were included. Primary repair and segmental resection of the duodenum with duodeno-jejunostomy were the two main methods used to repair ADF.
Results
Among the 15 patients analyzed, most were male, and the median age was 68 years. Based on the cause of ADF, five patients had primary ADF, whereas the remaining had secondary ADF. The average duration from fistula diagnosis to surgery was 23.5 days (2.8 days in primary ADF cases and 33.8 days in secondary ADF cases). Primary repair of the ADF was performed for eight patients, and segmental resection of the duodenum with duodeno-jejunostomy was performed for the remaining patients. Omentopexy was performed for all patients. The median duration of hospital stay was 32.7 days. Three patients died after surgery; however, all 11 patients operated on by the single experienced surgeon survived until the last follow-up.
Conclusion
To the best of our knowledge, this study is the first original article on ADF. Our findings suggest that ADF repairs performed by experienced surgeons would provide favorable results. Although primary repair is the first treatment choice, duodeno-jejunostomy is recommended when it is not feasible. By choosing the appropriate procedure depending on the case, favorable outcomes without any fatalities can be achieved.
Graphical Abstract
INTRODUCTION
Aortoduodenal fistula (ADF) is an unusual connection between the abdominal aorta and the duodenum. A primary ADF, first described by Sir Astley Cooper in 1822, is caused by spontaneous erosion of the aorta into the duodenum with an incidence rate at autopsy of 0.04%–0.07%.1, 2 Primary ADFs are mainly caused by either an abdominal aortic aneurysm (AAA), owing to an atherosclerotic aneurysm, or a traumatic or mycotic aneurysm.3, 4, 5 Secondary ADF occurs as a result of prior aortic surgery, mostly related to a previous AAA repair, with an incidence rate of 0.5%–2.3%.3
Nonetheless, surgeons must be prepared to promptly diagnose and treat this rare yet fatal condition. Although we lack consensus on the proper treatment for an ADF, surgical management remains the primary treatment modality.6 Notably, the perioperative mortality of patients with an ADF is ≥50%, and the survival rate is 18%–93%.7
We recently performed over 10 ADF repair surgeries with favorable postoperative results. To determine an evidence-based treatment policy, we reviewed these cases and analyzed the characteristics and outcomes of the patients. Considering that only case reports and review articles have been published on ADF, to the best of our knowledge, we present the first original article on the appropriate surgical techniques to treat an ADF.
MATERIALS AND METHODS
The data of patients diagnosed with ADF at the Yonsei University Gangnam Severance Hospital, South Korea, between January 2019 and August 2022 were collected. An ADF was confirmed based on the preoperative image and intraoperative findings. The clinical features were analyzed based on the medical records of patients. The surgery was performed in two stages: graft replacement of the aorta was performed by a cardiovascular surgeon, followed by procedures to treat the duodenal injury by a gastrointestinal surgeon. Primary repair or segmental resection of the duodenum with duodeno-jejunostomy was performed to repair the duodenal injury. This study was approved by the Institutional Review Board of Gangnam Severance Hospital, Yonsei University College of Medicine (IRB Number: 3-2023-0175).
Surgical techniques
First, the cardiovascular surgery team performed a graft replacement of the aorta. They clamped the aorta at the infra-renal level, and removed the damaged aorta segment, replacing it with an antibiotic-soaked prosthetic graft. Subsequently, the gastrointestinal surgery team continued the surgery and repaired the injured duodenum. An initial exploratory procedure was performed to evaluate the extent of the fistula (Fig. 1A).
Fig. 1
Two methods used for aortoduodenal fistula repair. (A) After dissection around the aortoduodenal fistula and repair of the aorta, the third and fourth portions of the duodenum were flipped upward. The fistula is observed at the posterior wall of the duodenum. (B) Primary repair of the injured duodenum. (C) Segmental resection of the duodenum with functional end-to-end duodeno-jejunostomy. (D) Common hole closure after duodeno-jejunostomy.
In cases where the size of the fistula around the duodenal wall permitted primary repair of the duodenum without tension, primary closure was performed with interrupted or continuous Lembert sutures; this was followed by reinforcement sutures in all cases (Fig. 1B).
In cases where over half of the circumference or a long segment of the duodenum was damaged or the grafted aorta directly compressed the injured duodenum, segmental resection of the duodenum followed by duodeno-jejunostomy was performed. After segmental resection of the duodenum, including the damaged duodenum, functional end-to-end anastomosis was performed using endoscopic linear staplers in a retrocolic fashion. The common hole was also closed with interrupted or continuous Lembert sutures (Fig. 1C and D).
The mobilized omentum was fixed between the repaired aorta and small bowels at the end of the surgery to prevent fistula recurrence.
Statistical analyses
Categorical variables are presented as numbers (percentage). The chi-square or Fisher’s exact test was used for categorical variables, as appropriate. Continuous variables are presented as mean and standard deviation. A Student’s t-test or Mann-Whitney U test was performed for continuous variables in subgroup analysis, as appropriate. A p-value less than 0.05 was considered significant. All statistical analyses were performed using IBM SPSS Statistics, version 26.0 (IBM Co., Armonk, NY, USA).
RESULTS
A total of 15 patients were diagnosed with ADF between 2019 and 2022. The patients were mostly male (86.7%) and aged between 50 and 78 years (median 68 years). All patients underwent surgical intervention to treat ADF. Cases are summarized in Table 1.
Table 1
Cases with an Aortoduodenal Fistula
Among the patients, 5 patients (33.3%) had primary ADF and 10 patients (66.7%) had secondary ADF. All primary ADF patients had AAA, and 3 (60.0%) of those cases were related to mycotic aneurysms. All the secondary ADF patients had graft infections. Of the 10 cases of secondary ADF, 5 (50.0%) had previously undergone endovascular aorta replacement (EVAR), and the other 5 (50.0%) had received open repair.
Nine patients (60.0%) presented with gastrointestinal bleeding, and 5 (55.6%) among them also had abdominal pain. All primary ADF patients experienced gastrointestinal bleeding, whereas only 4 of 10 (40.0%) with secondary ADF showed such symptoms. Four patients (26.7%) presented with fever and myalgia, and 1 (6.7%) exhibited no specific symptoms. The classic triad of symptoms, consisting of gastrointestinal hemorrhage, pain, and a pulsatile mass, was not observed in any patients. In secondary ADF, it took variable ranges of times, from 2 weeks to 138 months (median 57.3 months), for symptom of ADF to occur after previous aortic surgery.
In all cases, ADF was diagnosed most commonly based on computed tomography (CT) results, followed by esophagogastroduodenoscopy (EGD) results. EGD was performed in 6 patients (40.0%), and duodenal ulcers were revealed as the source of the bleeding in only 2 cases (Fig. 2). The presence of ADF was confirmed using a CT scan in 13 out of 15 patients (86.7%) (Fig. 3).
Fig. 2
Findings indicative of an aortoduodenal fistula on endoscopic gastroduodenoscopy (white arrows). Duodenal ulcer and exudate are observed.
Fig. 3
Aortoduodenal fistula on computed tomography (yellow arrow).
During surgery, the location of ADF could be grossly confirmed; all the lesions were identified in the third to the fourth portion of the duodenum. The time from the onset of symptoms to surgery for an ADF repair was variable and ranged from 0 to 117 days (median duration, 23.5 days), with a shorter median duration in primary ADF (2.8 days) compared with that in secondary ADF (33.8 days). Only 2 patients (13.3%) underwent surgery within 24 hours, 6 (40.0%) between 1 and 7 days, and 7 (46.7%) a week after their initial bleeding episode.
The aortas of all patients were replaced with antibiotic-soaked grafts. Eight patients (53.3%) underwent primary repair, and 7 (46.7%) underwent segmental resection of the duodenum with duodeno-jejunostomy. Aneurysm contents were cultured in 7 patients (46.7%) during surgery, and gram-negative, rod-shaped Enterobacter and Escherichia species were detected in 4 patients (26.7%).
Antibiotics were used to control or prevent peri-operative infection in all patients during hospitalization. The postoperative course was uneventful for all patients except for two. One patient underwent Fogarty embolectomy on postoperative day 90 owing to graft occlusion and growing pseudoaneurysm. The other patient suffered from duodenal stump leakage, and percutaneous drainage was performed for controlled fistula formation. These two cases had the longest hospitalization period after surgery (108 days and 56 days, respectively). The median hospital stay, from surgery to discharge, was 32.7 days (range: 13–108 days).
After surgery, 3 patients (20.0%) died, 2 (66.7%) owing to leakage of bowel contents followed by septic condition with multiple organ failure, and 1 (33.3%) owing to recurrence of ADF resulting in hypovolemic shock.
A single experienced gastrointestinal surgeon (surgeon A), who has performed over 200 gastrointestinal-related surgeries annually over 5 years, conducted ADF surgery on a total of 11 cases, resulting in favorable outcomes. This prompted additional subgroup analysis on the four cases performed by other surgeons (Table 2). It revealed significant difference in survival outcomes (p=0.009).
Table 2
Subgroup Analysis by Surgeon
DISCUSSION
ADF is a fatal disease with an approximately 100% mortality rate when not diagnosed and treated properly.8 ADFs are classified as primary ADF or secondary ADF, depending on the etiology. Primary ADF is multifactorial, associated with atherosclerotic disease, infections, and peptic ulcer disease.9 Expanding AAA irritates and inflames duodenum over time, resulting in fibrotic adhesion, pressure necrosis, and primary ADF.10 Secondary ADF is caused by erosion of the aortic graft after a previous aortic surgery.11 Over half of the fistulas affect the third or fourth portion of duodenum due to its anatomical fixation near the aorta.12
Gastrointestinal bleeding is one of the most common symptoms observed in approximately 64%–85% of patients with ADF.3, 6 The initial bleeding, known as “herald bleeding,” is usually self-limiting and is followed by lethal exsanguination. Over 50% of our patients complained of gastrointestinal bleeding (54.5%), whereas none exhibited the triad of symptoms, which also included abdominal pain and a pulsatile abdominal mass. Diagnosis based on symptoms alone has its limitations; therefore, additional imaging studies are required.
EGD and CT scans were primarily used for evaluation. CT with contrast is a more reliable imaging technique to detect ADF and has a sensitivity of 50%–94%, specificity of 85%–100%, and detection rate of 61%.13 The CT findings suggestive of an ADF include abnormal gas in the aorta, focal bowel wall thickening, disruption of aortic fat cover, pseudoaneurysm, retroperitoneal inflammation, and disappearance of the fat plane between the duodenum and aorta.12 CT has become the preferred initial diagnostic test since it is non-invasive and quick.3 Although EGD is essential to exclude other etiologies of gastrointestinal bleeding, the angulation and duodenal mucosal folds render it challenging to visualize ADFs past the third duodenal segment. Its detection rate is only 25%, with low sensitivity.14 Other methods available for diagnosis include arteriography, magnetic resonance imaging, ultrasonography, enteroclysis, and tagged white blood cell scans, which are not commonly used.12
Exploratory laparotomy for fistula disconnection is choice of treatment. Three main objectives should be considered while treating an ADF, including hemorrhage control, contamination/infection control, and maintenance of distal perfusion. Surgery is the primary treatment to disconnect the abnormal connection between the aorta and gastrointestinal tract.6 These include in situ graft replacement, primary defect closure, extra-anatomic bypass, and endovascular stent-graft replacement.12 The surgery was performed in two stages: vascular surgery to replace the aorta with antibiotic-soaked prosthetic grafts, and enteral surgery to repair the injured duodenum with primary repair or duodeno-jejunostomy followed by omentum pedicle fixation to prevent fistula recurrence. Each stage of the surgery was performed by a team of specialists in their respective fields. Previous studies have reported mortality rates of between 30% and 40% after ADF surgery.12 However, successful surgical outcomes with a 0% mortality rate were observed in all patients who underwent surgery by experienced gastrointestinal surgeons at our institution. No severe complications were observed postoperatively, and the survival rates among patients were 100% until the last follow-up.
However, selection bias could have affected the high survival rate. Many patients who could not undergo surgery or died in transport or in the emergency room were inevitably excluded from the study. Patients who could undergo surgery were in relatively favorable condition.
Additionally, the period from diagnosis to surgery was longer than anticipated, with a median duration of 23.5 days. Since it was quite a long period, infection source control, such as broad spectrum antibiotics and percutaneous drainage catheter insertion, if possible, was required for favorable outcomes after surgery, especially for secondary ADF. This also suggests that patients should be transferred to hospitals with expert personnel to receive proper treatment except in cases of emergencies. However, in primary ADF, urgent laparotomy is mandatory for avoiding hemorrhagic shock associated complications.15
Recently, EVAR has emerged as an effective option for unstable patients, serving as a temporizing method.7 Although EVAR is a minimally invasive procedure, it cannot completely repair an ADF when it is associated with an ongoing or new infection as well as recurrent bleeding.16 Nevertheless, it serves as a useful bridging method until surgical treatment is ultimately received.17
This study had several limitations. First, it was a retrospective, single-institution study with a small sample size. However, conducting a prospective study with a well-designed protocol is not feasible owing to the rarity of the disease. Second, despite the careful review of medical records, data collection was potentially limited by the incomplete documentation of initial symptoms, specific operative descriptions of ADF, and follow-up. Nevertheless, this is the first original article on the appropriate surgical techniques to treat ADF. Additionally, our hospital is one of the institutions that perform many AAA repair cases in Korea as a referral center of vascular surgery. Therefore, only operable cases of ADF were transferred, so that patients diagnosed with ADF were the same as those who underwent surgical treatment for ADF. However, we had a relatively large number of ADF patients, likely making us the institution with the highest number of ADF cases in the country.
The evaluation and treatment for ADF are summarized in a flow chart (Fig. 4). In conclusion, ADF repairs performed by experienced surgeons provided favorable results. While primary repair is usually the first treatment of choice, duodeno-jejunostomy is recommended whenever primary repair is not feasible. Selecting the appropriate procedure depending on the case could help achieve favorable outcomes without fatalities.
Fig. 4
Evaluation and treatment for aortoduodenal fistula.
The authors have no potential conflicts of interest to disclose.
AUTHOR CONTRIBUTIONS:
Conceptualization: In Gyu Kwon.
Data curation: Ji Eun Jung.
Formal analysis: Ji Eun Jung and Seyeol Oh.
Investigation: Ji Eun Jung and Seyeol Oh.
Methodology: Ji Eun Jung and In Gyu Kwon.
Project administration: Ji Eun Jung and Seyeol Oh.
Resources: Ji Eun Jung.
Software: Ji Eun Jung.
Supervision: In Gyu Kwon.
Validation: Ji Eun Jung and In Gyu Kwon.
Visualization: Ji Eun Jung.
Writing—original draft: Ji Eun Jung and In Gyu Kwon.
Writing—review & editing: Ji Eun Jung and In Gyu Kwon.
Approval of final manuscript: all authors.
AVAILABILITY OF DATA AND MATERIALS
The datasets used and analyzed during the current study are available from the corresponding author upon reasonable request.
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Korkut AK, Arpinar E, Yasar T, Guney D. Primary aortoduodenal fistula complicated by abdominal aortic aneurysm. J Cardiovasc Surg (Torino) 2000;41:113–115.
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