Infected stent graft and severe aortitis after transcaval glue embolization of type II endoleak: a case report

Introduction

Type II endoleaks after endovascular repair of infrarenal aortic aneurysm are as common as 8–10% (1). Type II endoleaks are considered low pressure and most do not cause enlargement of the aneurysm sac. Treatment guidelines recommend to embolize only in the presence of at least 5 mm increase of the aneurysm sac diameter (2). The most common mode of embolization is transarterial but there are instances when an extra-arterial approach is considered. Percutaneous image-guided direct sac puncture or transcaval access are two examples of extra-arterial routes. With both options, there is a risk of extravasation of the embolizing medium outside the aneurysm sac, with consequences that currently are still not well understood. Introduction of bacteria into the aneurysm sac is also a risk. In this case report, we describe a 71-year-old male who underwent infected endograft explant and aortic reconstruction with cryopreserved graft four weeks after the patient had undergone transcaval embolization with coils and n-butyl 2-cyanoacrylate (n-BCA) glue. We present this case in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-23-148/rc).

Case presentation

The subject is a 71-year-old male with a history of 5.5 cm infrarenal aortic aneurysm, treated endovascularly with a Gore Excluder stent graft (26 mm × 14.5 mm × 14 mm main body graft, left contra limb 23 mm × 12 cm, right limb extension 23 mm × 10 cm). The procedure was performed in elective fashion under general anesthesia, and standard peri-operative antibiotic was administered. The inferior mesenteric artery was chronically occluded. There were few, small patent lumbar vessels that were not embolized. The patient was discharged the following day after an uneventful night. During the follow-up, the aneurysm sac had shrunk from 5.5 to 3.5 cm in the first 2.5 years after the procedure. The patient’s risk factors included coronary artery disease status post coronary artery bypass and tissue mitral valve replacement; congestive heart failure; peripheral artery disease; bilateral popliteal artery aneurysms; hyperlipidemia; hypertension; type II diabetes; chronic obstructive pulmonary disease; and a 35-pack-year history of smoking. A month before the symptoms started, the patient underwent transcaval embolization with coil and n-BCA glue of the type II endoleak, which had caused sac enlargement from 3.5 to 5.1 cm over 12 months. The procedure was performed in the IR suite, under general anesthesia, through right femoral vein access. No periprocedural antibiotic was used. A curved metal cannula was placed in the lower inferior vena cava and multiple passes with a 4 French catheter were directed into the aortic sac to deliver the coils and glue. The procedure was uneventful, and patient was discharged home the same day. He presented to the emergency room with worsening abdominal pain, chills, failure to thrive, and 20-pound weight loss. Symptoms started a few days after he underwent transcaval embolization with coil and n-BCA glue to treat a type II endoleak. A computed tomography (CT) angiogram showed thickening of the aneurysm wall, air pockets inside the sac which were present on CT following embolization, and dense inflammatory changes around the aorta, concerning for a patient with aortitis (Figures 1,2).

Figure 1 Computed tomography imaging status post trans-caval glue embolization. Peri-aneurysm fat stranding with white arrow indicating air inside the aneurysm sac.

Figure 2 Four weeks status post trans-caval glue embolization. Severe arteritis noted by white arrows in sagittal (left image) and axial views (right image).

The patient was admitted with concern for chemical induced aortitis versus infected graft and treated with intravascular fluid resuscitation, broad spectrum antibiotics, optimization of nutrition, and pain control. On physical exam, he displayed some abdominal tenderness to palpation. Lab workup included blood and urine cultures, which were negative; a white blood cell counts at 11.1×10⁹/L; and a C-reactive protein at 101.6 mg/L. With no identifiable infectious causes, despite repeat cultures and lab work, further investigation was conducted as follows: autoimmune panel (negative), gastrointestinal pathogen panel (negative), and blood antibody evaluation (negative). Positron emission tomography (PET) imaging was consistent with an inflammatory or infectious process (Figure 3). Ultimately, a transabdominal CT-guided biopsy just off midline to the left of the umbilicus at the level of the aortic bifurcation of the peri-aortic tissue was performed and cultures were positive for Staphylococcus epidermidis and Cutibacterium acnes. The patient underwent preoperative cardiovascular evaluation which showed an ejection fraction of 36% and no concerns for artificial valve vegetations. After an in-depth conversation with the patient and his family addressing risks and benefits, the decision was made to perform graft explant.

Figure 3 Positron emission tomography imaging during pre-operative hospitalization. Fluorodeoxyglucose avid low-density soft tissue thickening and stranding identified by white arrows about the infrarenal abdominal aneurysm sac extending to the level of the bifurcation.

The patient was brought to the operating room where ureteral stents were placed. Right thigh fascia lata was harvested for aortic and iliac anastomosis reinforcement. A midline, transabdominal approach was used to expose the aorta. Upon entering the abdomen, there was an atypical dense central adhesive process with mesojejunum, mesosigmoid, and the fourth part of the duodenum adhered to the aneurysm sac. The meso-sigmoid, the left common iliac artery bifurcation, and the ureter were encased by a dense inflammatory reaction. Proximal aortic control was obtained first by dissecting the suprarenal aorta, which was spared from inflammation. Subsequently, left internal and external iliac as well as right common iliac arteries were dissected free and controlled with vessel loops. The mesojejunum, which was covering most of the antero- and left-lateral aspect of the aneurysm sac, was divided in an avascular plan to expose the aortic sac. Heparin was administered to obtain therapeutic activated clotting time greater than 250 s; the clamp was placed in the suprarenal position with open jaws; and the aneurysm sac was entered in its left lateral aspect, away from the duodenum and a few centimeters above the aortic bifurcation. While entering the sac, a large pocket of purulence was noted to be collected around the graft (Figure 4). Some of the infected tissue was removed without aortic clamping, taking advantage of the presence of well-sealed endovascular graft. No type II endoleak was identified. At this point, the suprarenal aorta and the iliac vessels were clamped and the graft removed. The juxtarenal aorta was opened longitudinally and endarterectomy performed in preparation for the anastomosis. After the endarterectomy was completed, the aortotomy was closed for about 5 cm, and the clamp was moved to an infrarenal position. Renal ischemia time was 7 minutes. The rest of the infected and inflamed aortic tissue was resected. A cryopreserved aorto-iliac graft was sutured proximally with 3-0 Prolene in a running suture. The distal anastomoses were performed to the right common iliac artery bifurcation and to the left external iliac artery. This was done by adding a segment of cryopreserved femoral artery (Figure 5). All suture lines were buttressed with fascia lata. Irrigation of the retroperitoneum with debridement antibiotic (DAB) solution including gentamicin, neomycin, and polymyxin B sulphate was performed. The graft was covered with a tongue of omentum and the abdomen was closed in multiple layers. Pathology revealed aortic tissue positive for Staphylococcus epidermidis and Cutibacterium acnes. Post-operatively, the patient remained hemodynamically stable. On the third postoperative day, the patient developed an acute kidney injury (peak creatinine 3.4 mg/dL), which resolved by discharge (creatinine 1.5 mg/dL). The intensive care unit (ICU) stay was only 2 days, and the total hospital stay was 11 days. Patient was discharged on 4 weeks of intravenous (IV) ceftriaxone. A follow-up protocol was set up for the patient consisting of a CT angiogram at 6 months, 2 years and every 5 years thereafter. At the 2-year post-operative follow-up, he had a repeat CT abdomen which demonstrated a patent graft in stable condition and patent (Figure 6). The patient’s white blood cell count remained low and he continued to be without concerns for infection. The patient was doing well, and his energy level had almost returned to baseline. A timeline highlighting major events by month/year is presented as Figure 7.

Figure 4 Intraoperative adhesiolysis. (A) Mesojejunum, mesosigmoid, and the 4th part of the duodenum adhered to the focus of inflammation; (B) after adhesiolysis with purulence identified with white arrow and iliac bifurcation indicated with white arrows to show relevant anatomy. Stick figure image indicates patient position in the operating room.

Figure 5 Final intraoperative image with mesocolon removed from the aneurysm sac as labeled. Debrided inflammatory tissue, proximal anastomosis, and right/left iliac limb reconstruction displayed and labeled with white arrows.

Figure 6 Six months follow-up CTA. Stable post operative evaluation. CTA, computed tomography angiogram.

Figure 7 Timeline of events arranged in sequence by month/year.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

This is the first case reported of aortitis and endograft infection after transcaval injection of n-BCA glue, at a 2:1 ethiodol-to-glue ratio, to treat a type II endoleak. N-BCA glue is available in the United States for treating arteriovenous malformations in the central nervous system. In the peripheral circulation, n-BCA has been used in a wide variety of conditions. Some of the advantages of this glue are the high radiopacity (making easy to trace it fluoroscopy), the quick time to embolization, low rate of vessel recanalization, and the ability to penetrate vascular beds in a flow-directed fashion. However, early polymerization of glue can occur in the microcatheter leading to the occlusion of lumen and potential loss of access. Excessive reflux around the microcatheter tip may occur with fast glue injection, increasing the risk of non-target embolization and complications. Most of these complications are avoidable by using proper technique. The transcaval route was decided as it was the most direct and closest route to the nidus of the endoleak. In addition, this route has shown to have high technical success and low morbidity rates (3). When cyanoacrylate is injected into a blood vessel, it creates an acute inflammatory reaction directly affecting the vessel wall. This inflammation leads to a chronic granulomatous foreign-body inflammatory reaction that causes fibrosis and vessel obliteration over the course of about one month (4). It has previously been documented that injection of n-BCA results in aortitis. In a study by Wojtaszek et al., follow-up images were performed after glue embolization which showed inflammation of the aortic wall up to ten mm thick (5). The inflammation was not associated with a rise in inflammatory markers and the patients remained asymptomatic. Similarly, our patient developed an intense aortic and periaortic inflammatory process which is not atypical after embolization. However, our patient became increasingly symptomatic over the course of four weeks with fatigue and pain. After significant inconclusive workup to try to distinguish between infection and inflammation, CT-guided tissue biopsy was the definitive diagnostic test. Negative peripheral blood cultures, in fact, do not rule out infection if no growth is seen after 5 days. There were no other sources of infection such as recent diverticulitis, cholecystitis, tooth abscess, urinary tract infection. Because of this and the very indicative timing (onset of symptoms during the first week after the embolization), the endovascular embolization was felt to be the most likely culprit. Identification of the underlying cause is critical in the development of the correct treatment strategy. While a temporary inflammatory reaction can often be managed with conservative treatment and serial imaging, treatment for an infected endograft is to explant. Peri-procedural administration of antibiotic during embolization is not required by any guidelines. Although this single case report does not provide strong evidence of the need for pre-embolization antibiotics, someone could argue that the administration of peri-embolization antibiotic might have prevented graft infection.

The mortality rate associated with open aortic endograft explantation is between 20% and 30% (6,7). The presence of severe inflammation encasing most of the aorta and adjacent meso-intestine, as in this case report, increases the level of difficulty and the risk of major complications. The classic retroperitoneal approach to opening the aneurysm sac in the left lateral aspect, away from the intestine, could not be applied in this case because the inflamed mesentery was covering the entire aneurysm sac. Therefore, the authors were forced to dissect some of the mesentery off the aneurysm sac, with the risk of disruption of the intestinal blood supply.

Suprarenal aortic control is usually needed to remove the endograft, unless the endograft has migrated, leaving a clampable infrarenal aorta. Several strategies are described to re-establish blood flow to the lower extremities, including endograft explant followed by in situ reconstruction (with either femoral vein and cadaveric grafts) or extra-anatomical bypass (i.e., axillo-bifemoral bypass) performed the same day or the day prior to endograft explant. In situ reconstruction has shown to be associated with lower risk of aortic blowout; however, it is technically more challenging and burdened by a higher complication rate (6-8). When approaching an inflammatory aneurysm or redo aortic surgery, bilateral ureteral stenting may prevent inadvertent injury. Buttressing of all anastomoses with biologic tissue (fascia lata, peritoneal patch, or prevertebral fascia) is intended to decrease the risk of anastomosis disruption. The aortic stump wall can also be out-folded to create a “double wall” to suture to. If the endograft is well-sealed and diverting flow, the aneurysm sac can be opened and some of the infected tissue can be debrided before the aorta is clamped, reducing the visceral ischemic time.

The limitations of this case report are that it is a single case and is unable to generate quantifiable data providing statistically significant conclusions. The strengths are that it provides an example of a rare case and provides new observations and insights with regard to the diagnosis strategy and surgical management.

Conclusions

This is the first case reported of aortitis and endograft infection after transcaval injection of n-BCA glue to treat a type II endoleak. Workup after embolization encompassed investigations of inflammatory vs. infectious causes; ultimately, CT-guided tissue biopsy was the definitive diagnostic test to differentiate between the two. Ureteral stents may help identify the ureter and minimize the risk of injury. The authors recommend in situ reconstruction with biological graft and buttressed anastomoses to reduce risk of aortic stump blowout. A well-sealed endograft may allow opening the aneurysm sac to perform some of the tissue debridement without clamping the aorta, thus reducing the renal ischemic time.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-23-148/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-23-148/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-23-148/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. van Marrewijk C, Buth J, Harris PL, et al. Significance of endoleaks after endovascular repair of abdominal aortic aneurysms: The EUROSTAR experience. J Vasc Surg 2002;35:461-73. [Crossref] [PubMed]
2. Chaikof EL, Blankensteijn JD, Harris PL, et al. Reporting standards for endovascular aortic aneurysm repair. J Vasc Surg 2002;35:1048-60. [Crossref] [PubMed]
3. Nana P, Spanos K, Heidemann F, et al. Systematic review on transcaval embolization for type II endoleak after endovascular aortic aneurysm repair. J Vasc Surg 2022;76:282-291.e2. [Crossref] [PubMed]
4. Fumarola E, Ierardi A, Piacentino F, et al. Glue or Onyx: A Guide to Choice –Tips and Techniques. Journal of Endovascular Resusitation and Trauma 2020;4:33-9. [Crossref]
5. Wojtaszek M, Wnuk E, Maciag R, et al. Improving the results of transarterial embolization of type 2 endoleaks with the embolic polymer Onyx. Wideochir Inne Tech Maloinwazyjne 2016;11:259-67. [Crossref] [PubMed]
6. Fatima J, Duncan AA, de Grandis E, et al. Treatment strategies and outcomes in patients with infected aortic endografts. J Vasc Surg 2013;58:371-9. [Crossref] [PubMed]
7. Smeds MR, Duncan AA, Harlander-Locke MP, et al. Treatment and outcomes of aortic endograft infection. J Vasc Surg 2016;63:332-40. [Crossref] [PubMed]
8. Brandt CP, Malangoni MA, Priebe PP, et al. Shackelford’s Surgery of the Alimentary Tract, 5th Edition. Ann Surg 2002;236:261.