If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Corresponding author. L. R. Leon Jr., MD, RVT, SAVAHCS – Department of Vascular Surgery, Chief AHSC – Assistant Professor of Clinical Surgery, 3601 South 6th Avenue. Vascular Surgery Section Room N259, Tucson, AZ 85723, USA.
Southern Arizona Veteran Affairs Health Care System (SAVAHCS) – Vascular Surgery Section, Tucson, Arizona, USAUniversity of Arizona Health Science Center (AHSC) – Division of Vascular Surgery, Tucson, Arizona, USA
Southern Arizona Veteran Affairs Health Care System (SAVAHCS) – Vascular Surgery Section, Tucson, Arizona, USAUniversity of Arizona Health Science Center (AHSC) – Division of Vascular Surgery, Tucson, Arizona, USA
Southern Arizona Veteran Affairs Health Care System (SAVAHCS) – Vascular Surgery Section, Tucson, Arizona, USAUniversity of Arizona Health Science Center (AHSC) – Division of Vascular Surgery, Tucson, Arizona, USA
Aortic graft-colonic fistulae are a rare complication of aortic reconstructive surgery.
Methods and findings
A comprehensive review of this entity was performed based on the available literature from 1950 until 2006. Available reports were analyzed with respect to demographics, prior surgical intervention and its indication, prosthetic material used during the initial intervention, clinical presentation, the time interval in between the initial operation and symptoms, the method of treatment of the aortic graft-colonic fistula and its outcome.
Aortic graft-colonic fistulae are rare and dreaded complications of aortic surgery. We performed an exhaustive literature review of this entity.
Literature Search
A MEDLINE search was carried out in all languages. A manual search was also performed using bibliographies from relevant publications. Search terms included aorto-enteric/aorto-colonic/aorto-intestinal fistula or erosion, paraprosthetic-enteric/paraprosthetic-colonic fistula, aortic graft infection, septic aortitis, diagnosis, presentation and management. Cases including the caecum or appendix were excluded; only cases involving the ascending, transverse, descending, sigmoid and were included (Table 1).
All studies identified were retrospective series or case reports. Data were analyzed for demographics, prior surgical intervention and indication, prosthetic material used during the first intervention, presentation and the time between the initial operation and development of symptoms or intervention, the treatment of the secondary aortoenteric fistula (SAEF), and outcomes (morbidity and mortality). Data were compared to the reported data concerning SAEFs involving all bowel segments, given that an analysis specifically of colonic SAEFs has not been previously performed.
Left leg rash, swelling and pain, left lower quadrant pain, sweating/108
Sigmoid
Axillobifemoral bypass+ligation of proximal left common femoral artery; later needed near-total graft excision; infrarenal aorta, right common iliac and left external iliac arteries ligation; sigmoid resection+primary anastomosis
Left extra-anatomic bypass (Dacron),right femoral and left common iliac artery ligation, aortic stump suture with prevertebral ligament reinforcement+omental flap coverage; right colectomy. Also needed femoro-femoral crossover bypass 2 weeks after
Twenty reports were single cases; the others included ≥2 cases of paraprosthetic-enteric fistulae (PEF). Most reports were published between 1980-1989 (16 papers).
Our gratitude to Dr. Rifat Latifi for translating the articles in foreign languages.
Aortic reconstruction has been performed for aortoiliac occlusive or aneurysmal disease for >50 years, with excellent results in terms of patency, morbidity and mortality.
studied 94 patients after non-ruptured abdominal aortic aneurysm (AAA) repair with CT scans obtained 8 to 9 years after repair. Abnormal findings were frequent, but were mostly clinically insignificant (65% of patients had evidence of aneurysmal dilatation, but in only 14% was surgical repair a consideration). Hallett et al.
analyzed 307 AAA operations over 33 years for graft-related complications. At a mean follow-up of 6 years (range: <1 month-36 years), 9% of patients had a graft-related complication.
Gastrointestinal (GI) tract erosion by an adjacent vascular prosthesis is a rare complication of aortic reconstruction, known as SAEF. Cases of erosion of a native vessel and the bowel (without prosthesis) are classified as primary aortoenteric fistulae. Some have made a distinction between SAEF, which is a true fistulous tract from the proximal suture line to the bowel lumen, and a paraprosthetic enteric fistula (PEF), also known as prosthetic or aortoenteric erosion, which is a communication between the GI tract and the external prosthetic graft body surface without actual fistulization into the lumen.
Erosion into the adjacent colon is thought to result from pressure necrosis due to constant graft pulsation eventuating in graft body erosion into the bowel.
may promote inflammatory adherence and subsequent erosion into the bowel wall. Additionally, retroperitoneal infectious processes (i.e. diverticular abscess or pancreatic pseudocysts) may predispose to graft erosion into the bowel wall. Our review identified colonic involvement almost exclusively after aortic reconstructions using bifurcated prosthetic grafts and rarely after the use of tube grafts.
The incidence of SAEF involving any enteric segment ranges from 0.4–1.6%;
noted that bowel was found to be intimately associated with the prosthetic graft in 7% (which did not imply a true fistulous connection). Hallett et al.
identified graft-enteric erosion/fistula in 1.6% of cases after AAA repair, with a median follow-up of 4.3 years. With regard to colonic involvement, Bergqvist
analyzed 631 cases of SAEFs, reporting sigmoid involvement in 2.4% of cases and appendix-colon (colon site not further specified) involvement in 4.2%. We were unable to precisely define the prevalence of SAEFs involving the colon given the paucity of large series and the multitude of case reports. We identified 53 colonic PEF cases (12.3%) among 430 reported PEFs involving all bowel segments. Affected patients tended to be elderly (mean age=65 years; range 47–83; age unknown in 19 cases) with strong male gender predilection (4.8:1; unknown in 18 cases), reflecting the patient population undergoing open aortic reconstruction.
only identified 1/21 patients with sigmoid involvement in their SAEF review. Among cases of colonic SAEF in our review, 3/4 cases involved the sigmoid (39/53; 73.6%); the transverse colon was involved in 4 cases (7.6%), whereas the ascending colon and a rectal stump were involved in one instance each (1.9% each). The site of involvement was not reported in 8 cases (15.1%).
Indication for initial operation
The initial indication for aortic reconstruction was equally divided between occlusive and aneurysmal disease with 15 cases each (11 intact and 4 ruptures; one of the 4 ruptured cases was associated with an aortocaval fistula
based on their reported series of 17 PEF cases, 14 of which developed after AAA repair. This assertion has not been universally confirmed. Although Armstrong et al.
concurred with Elliott's observations (identifying as the indication for aortic reconstruction an aneurysm in 72% of their patients (21) with SAEFs, and aortoiliac occlusive disease in 28%). Vollmar and Kogel
found a higher incidence of SAEFs after reconstruction for occlusive disease (1.1% vs. 0.2% for aneurysms). Six of Vollmar's initial procedures for aneurysms were performed for rupture AAA, while 15 were elective. Kuestner et al.
found that among 21 cases of PEF, AAA had been the indication in 14 (6 ruptured and 8 elective) and the remaining 7 followed therapy for aortoiliac occlusive disease. Our review of aorto-colonic fistulae identified an equal proportion of cases recognized after operations for occlusive disease and AAA.
Type of initial operation
In 17 cases, the type of surgery was not cited (an additional 4 cases had an imprecise description of the procedure). Precise proximal and distal anastomotic sites were not generally stated. We were able to infer that the procedure most commonly performed was an aortoiliac graft in 17 cases (unilateral aortoiliac in 12, aortobiiliac in 5), followed by aortofemoral grafts in 11 cases (aortobifemoral in 7; unilateral aortofemoral in 4). Other operations reported included left iliofemoral (2), thoracoabdominal-iliac (1) and aorto-popliteal (1) bypass grafts. An association between the specific types of aortic reconstruction and the subsequent development of a SAEF has not been previously reported. In the series collected by Armstrong et al.
an aortobifemoral bypass configuration was most commonly noted (n=19), with aortobiiliac (n=7) and aortic tube grafts (n=3) less frequently reported.
Several reports have related their experience with alternative surgical reconstructive techniques. A 10-year experience with 831 patients (761 elective, 70 urgent) undergoing the retroperitoneal exclusion technique to treat infrarenal AAA was reviewed.
suggested that the use of paramedian retroperitoneal incisions for aortic reconstructions provides an intact peritoneum and retroperitoneal fat tissue layer to protect the graft from the viscera. They also preferred an end-to-end over end-to-side anastomosis in aortobifemoral bypasses, in order to allow placement of prosthetic cuff slid over the proximal anastomosis to cover the suture line. The latter technique is controversial.
most repairs had been performed using Dacron grafts (n=27) except two cases with polytetrafluoroethylene (PTFE) conduits. Our review identified Dacron as the most frequent material used, with only one report involving PTFE.
This reflects the preference for the use of Dacron for inflow arterial reconstructions. Dacron is thought to promote a foreign body reaction to adjacent bowel and eventually erode into it.
Suture material has also been related to SAEFs. Silk sutures, historically used for arterial-graft anastomosis, degenerate over time, resulting in primary suture failure with pseudoaneurysm formation and eventual SAEF.
Permanent synthetic sutures have reduced the incidence of suture line failure.
Time interval for diagnosis
SAEF tends to present late. This information was available for 33 cases. The mean interval between the initial operation and symptom development was 59.5 months (range: 1–324). This is in agreement with prior reports, the average being approximately 72 months.
reported a mean interval between placement of the original aortic graft and definitive treatment of SAEF of 73.2±49.2 months. O'Mara and Imbembo reported an average of 22 months (range: 1–84).
published similar results in their series of 11 SAEFs (1–73 months; mean 34).
Clinical presentation
The most frequent presenting sign of SAEF is massive upper GI bleeding. SAEF should always be suspected in a patient after aortic prosthetic reconstruction who presents with GI hemorrhage. In colonic PEF cases, massive bleeding is not seen as often given that there is no true communication between the prosthesis lumen and the bowel. Therefore, absence of GI bleeding does not rule out the presence of PEF. Other reported presentations include sepsis, malaise, weight loss and other non-specific symptoms.
Our review indicates that GI bleeding is the most prevalent presentation (in 24 instances: melena [3], hematochezia [15] and non-specified GI bleed [6]), but it was not frequently massive. When seen, bleeding is often the result of exposed bowel mucosa surrounding the eroding prosthetic limb.
noted that 14/21 of patients with PEFs present with sepsis, regardless of the involved bowel segment. At the same time, overt GI bleeding as the presenting symptom occurred in 19% (4/21) and abdominal pain in 14%. Rosenthal et al.
suggested that whenever patients present with a history of aortic reconstruction and fever, aerobic and anaerobic blood cultures are indicated. If these are positive for enteric organisms, the diagnosis of SAEF should be strongly suspected. Clostridial graft infection also has been rarely reported.
The most frequent symptoms and signs reported in our series include abdominal pain (6), leg pain or edema (4), chills (4), abdominal mass (3) and diarrhea (2). A high index of suspicion is essential for diagnosis, since there is a substantial subset of patients with nonspecific clinical findings in whom routine studies are not diagnostic. This is especially true for colonic as opposed to duodenal PEF.
Diagnosis
Following development of signs and symptoms, SAEF diagnosis is typically delayed, by as long as 1 month in 50% of patients in one report, with the diagnosis being made within 10 days of hospitalization in only 15% of cases.
18-fluorodeoxyglucose positron emission tomography as a novel imaging tool for the diagnosis of aortoenteric fistula and aortic graft infection–a case report.
These techniques are not definitive, but provide useful supportive information when other findings are inconclusive.
Whereas upper endoscopy is very helpful in both visualizing a possible SAEF and excluding other causes of GI bleeding, the benefits of colonoscopy have been infrequently reported. Nevertheless, lower endoscopy was the definitive diagnostic study of SAEF in a patient we recently reported (Fig. 1).
diagnosed a PEF involving the limb of an aortobifemoral graft and the sigmoid in a patient 10 years after an open AAA repair.
Fig. 1Colonoscopy finding in a 58 year-old male patient who presented to our institution with a history of aortobifemoral graft performed two years prior due to critical limb ischemia. Computed tomography and a white blood cell scan performed previously suggested the presence of an aortic paraprosthetic-colonic fistula. The Figure shows the left limb of the graft within the colonic lumen, which undoubtedly established the diagnosis.
Interestingly, even with surgical exploration, the relationship between the graft and the intestinal site involved in some cases cannot be established. Bergqvist et al.
reported four such cases where the graft was lying in a pool of pus and the site of GI involvement could not be precisely identified. Interestingly, in about 7% of cases, more than one fistula in the same patient was identified.
graft excision alone, local repair with the original prosthetic left in-situ or graft excision with in-situ replacement using a new prosthesis with or without antibiotic-bonding. Reported outcomes using these approaches are variable. More aggressive strategies, with enteric excision and GI tract restoration, prosthesis removal, infrarenal aortic stump closure and immediate extra-anatomic axillobifemoral bypass (EAB) have also been described. The latter approach has been the most traditional recommendation. SAEF is associated with a high operative mortality (about 52%) and significant morbidity (e.g. recurrent infection; aortic stump blowout). Graft excision and EAB either as a single or staged procedure is still the most commonly used treatment for SAEF.
In situ reconstruction with cryopreserved arterial allografts for management of mycotic aneurysms or aortic prosthetic graft infections: a multi-institutional experience.
Sivamurthy N, Hiramoto JS, Schneider DB, Eichler CM, Reilly LM. Cryopreserved superficial femoral vein: the optimal conduit for the in situ treatment of aortic graft infection? [Abstract]. In: Western Vascular Society, Annual Meeting, 2006.
Other approaches have been individually considered. For instance, GI defect closure, partial excision and replacement of the inserted vascular prosthesis, an encircling omental sleeve covering the prosthesis and anastomoses has been used.
have recommended stapling the bowel loops involved in the SAEF with a GIA device in cases of massive bleeding. This is done to tamponade the bleeding, allowing time to dissect the graft and to clamp the infrarenal aorta. They also recommended this technique for cases of undiagnosed GI bleeding in a hospital with no vascular units, in order to stabilize the patient for transfer to a tertiary center.
The technique for GI tract reconstruction differs in cases of colonic compared to duodenal or jejunal involvement. For the latter, either a lateral bowel repair
or resection and end-to-end anastomosis of grossly normal bowel usually suffices, given the lower virulence of the bacteria populating the upper GI tract compared with the lower. The bowel can be hand sewn, or anastomosed end-to-end with an EEA stapler or side-to-side with a GIA stapler.
Colonic defects are managed differently. They can be repaired with either direct closure, or resection with either primary anastomosis or stoma creation. During surgical exploration, it is crucial to fully mobilize the bowel; despite a normal appearing anterior bowel wall, a posterior wall erosion could be missed.
Colostomies in the sigmoid (Hartmann's procedure) or transverse colon are thought to allow immediate fistula control with minimal intraperitoneal contamination. The colostomy site should be placed away from the axillofemoral graft and can be left closed, to be opened postoperatively to avoid further intraoperative contamination.
SAEFs tax the ingenuity of vascular surgeons. Our review showed a wide variety of therapies, including intestinal stomas or primary colonic repair; graft removal with extra-anatomic bypass for revascularization or graft revision (the latter by replacing the involved graft with homograft or with a new prosthetic graft, aided by omental interposition, re-suturing of a previously involved anastomosis, or endovascular placement of a stent-graft). The wide variety of approaches and the small number of patients treated are not sufficient to provide evidence-based recommendations.
Morbidity and mortality
Most reports failed to cite follow-up periods (28 papers). For those studies that did so, the time span was very wide (0–72 months; average 8.4). All but three investigators documented follow-up periods of <2 years. The short-term outcomes in patients with aorto-colonic fistulae were generally favorable (22). In 19 cases the outcome was unknown. Ten patients died of a cause directly related to the SAEF or to its therapy. One patient was reported dead from unrelated causes (not specified). Complications reported after treatment of a PEF include pulmonary embolism, infected pseudoaneurysm, bilateral graft limb thrombosis, above-the-knee amputations, recurrent infection, limb or colon ischemia and renal failure.
Conclusions
SAEF involving the colon is a rare but well-known complication of aortic reconstructive surgery. It is a dreaded one, associated with high morbidity and mortality. High clinical suspicion and prompt therapy are essential in the management of these patients to avoid catastrophic consequences due to a delayed recognition of a highly treatable condition.
References
Ferris E.J.
Szego Koltay M.R.
Koltay O.P.
Sciammas F.D.
Abdominal aortic and iliac graft fistulae.
Am J Roentgenol Radium Ther Nucl Med.1965; 94: 416-420
18-fluorodeoxyglucose positron emission tomography as a novel imaging tool for the diagnosis of aortoenteric fistula and aortic graft infection–a case report.
In situ reconstruction with cryopreserved arterial allografts for management of mycotic aneurysms or aortic prosthetic graft infections: a multi-institutional experience.
Sivamurthy N, Hiramoto JS, Schneider DB, Eichler CM, Reilly LM. Cryopreserved superficial femoral vein: the optimal conduit for the in situ treatment of aortic graft infection? [Abstract]. In: Western Vascular Society, Annual Meeting, 2006.
To submit a comment for a journal article, please use the space above and note the following:
We will review submitted comments as soon as possible, striving for within two business days.
This forum is intended for constructive dialogue. Comments that are commercial or promotional in nature, pertain to specific medical cases, are not relevant to the article for which they have been submitted, or are otherwise inappropriate will not be posted.
We require that commenters identify themselves with names and affiliations.
00461-3&id=gr1.jpg){kind=link}