Imaging Findings of Atypical Type II Endoleak Through Vasa Vasorum After Abdominal Endovascular Aneurysm Repair

CIRSE Standards of Practice on Management of Endoleaks Following Endovascular Aneurysm Repair

BACKGROUND

Endoleaks represent the most common complication after EVAR. Some types are associated with ongoing risk of aneurysm rupture and necessitate long-term surveillance and secondary interventions.

PURPOSE

This document, as with all CIRSE Standards of Practice documents, will recommend a reasonable approach to best practices of managing endoleaks. This will include imaging diagnosis, surveillance, indications for intervention, endovascular treatments and their outcomes. Our purpose is to provide recommendations based on up-to-date evidence, updating the guidelines previously published on this topic in 2013.

METHODS

The writing group was established by the CIRSE Standards of Practice Committee and consisted of clinicians with internationally recognised expertise in endoleak management. The writing group reviewed the existing literature performing a pragmatic evidence search using PubMed to select publications in English and relating to human subjects up to 2023. The final recommendations were formulated through consensus.

RESULTS

Endoleaks may compromise durability of the aortic repair, and long-term imaging surveillance is necessary for early detection and correct classification to guide potential re-intervention. The majority of endoleaks that require treatment can be managed using endovascular techniques. This Standards of Practice document provides up-to-date recommendations for the safe management of endoleaks.

[Late Open Semi-conversion with Endograft Preservation for (Type II) Endoleaks with Late Aneurysm Sac Enlargement after EVAR - Indications, Method and Results in Our Own Patient Collective]

EVAR (endovascular aortic repair) is the most common method for treating an abdominal aortic aneurysm, but according to the latest findings it carries the risk of subsequent complications. These can be caused by (late) aneurysm sac growth. If conservative and surgical therapies fail to treat the aneurysm sac growth, open conversion is necessary to prevent aneurysm rupture. There are several options for open conversion, in which the EVAR prosthesis can be completely preserved or is (partially) removed. Late open semi-conversion with complete in-situ preservation of the EVAR-prosthesis and gathering of the aneurysm sac are a less invasive method than complete conversion and may be performed instead for selected patients. The aim of the present work is to present the surgical method, including indications and technical information, as well as the presentation of the results in our recent patient collective.All patients semi-converted in our department of vascular surgery and phlebology due to (type II) endoleak were included. All data are presented as n (%) or median (range).Between 6/2019 and 3/2023, 13 patients underwent semi-conversion 6 (2-12) years (median, range) after the initial EVAR. The aneurysm sac diameter at the time of semi-conversion was 69 mm (58-95 mm), the operating time was 114 min (97-147 min), the blood loss was 100 ml (100-1500 ml). Five (38%) patients received blood transfusion intraoperatively and 2 (15%) postoperatively. The stay in the intensive care unit lasted 1 (1-5) days, the hospitalisation time was 8 (6-11) days. Postoperative complications were intestinal atony (3 [23%], 1 [8%] with nausea/emesis and gastric tube insertion), anaemia (2 [15%]), hyponatraemia (2 [15%]), delirium (1 [8%]), COVID-19 infection (1 [8%]) and 1 [8%] intra-abdominal postoperative bleeding with the indication for surgical revision and the transfusion of 8 erythrocyte concentrates.Semi-conversion is a safe and practicable surgical method with few severe complications for a selected group of patients, which should be considered as an alternative to more invasive methods with (partial) removal of the EVAR-prosthesis. Further long-term studies comparing semi-conversion to full conversion are needed to demonstrate its benefits.

Enlarging aneurysm sac post EVAR - type V or occult type II Endoleak?

PURPOSE

Several theories exist regarding the underlying mechanism of type V endoleaks (T5EL), which remains unclear. Torikai et al. (2018) describe sac expansion in cases with patchy heterogenous enhancement of peripheral thrombus and postulate these are due to atypical type II endoleaks (T2EL) from proliferated vasa vasora. These cases of apparent endotension pose a therapeutic challenge as continued sac expansion warrants active intervention.

MATERIALS AND METHODS

Retrospective review of T5EL cases was performed who underwent multidisciplinary discussion at our institution between 2020-2021. Clinical history and imaging were reviewed by a vascular interventional radiologist aiming to identify the underlying mechanism of sac expansion.

RESULTS

Two cases of these specific T5ELs were identified. One patient underwent endovascular management and image-guided aspiration of intra-sac fluid whilst another underwent open surgical ligation and sac plication. In both cases, fluid re-accumulated with re-expansion of the aneurysmal sac on follow-up. Careful review of CT imaging showed subtle foci of peripheral sac enhancement, suggestive of vasa vasora causing occult T2ELs. This was not visible on single phase CTA, super-selective angiography or cone beam CT.

CONCLUSION

We identified two complex cases with unexplained sac expansion following EVAR suggestive of T2ELs from proliferated vasa vasora. Transcatheter embolisation of this network of vessels although challenging has been previously considered to stunt sac expansion. We suggest this phenomenon is under-diagnosed. Nevertheless, long-term surveillance is warranted as continued sac expansion risks changes in aneurysm morphology leading to potential loss of the proximal/distal seal zones.

Surgical Treatment of Sac Enlargement Due to Type II Endoleaks Following Endovascular Aneurysm Repair

An aneurysm sac enlargement caused by type II endoleak (T2EL) following endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms may cause serious complications such as rupture. Consequently, methods that preoperatively prevent or postoperatively treat T2EL have been employed. When significant aneurysm enlargement occurs due to persistent T2EL, embolization is first performed through several access points. However, although these endovascular reinterventions have a high technical success rate and are safe, their effectiveness remains questionable. When such endovascular procedures fail to stabilize sac enlargement, open surgical conversion (OSC) becomes the last-resort treatment option. We review several strategies of OSC for the repair of T2EL following EVAR. Among the three main OSC procedures, namely, complete endograft removal, partial endograft removal, and complete endograft preservation, partial endograft removal under infrarenal clamping was considered the most appropriate owing to its less invasiveness and durability.

Embolization of Type 2 Endoleaks in the Abdominal Aorta Using Ethylene Vinyl Alcohol Copolymer

BACKGROUND

 Type 2 endoleaks (T2EL) are the most frequent complication following endovascular aortic repair. Multiple studies primarily deal with the technical and clinical success of the embolization of persisting T2EL, thereby revealing controversial outcomes. Current reports rarely focus on the detailed execution of such a complex interventional procedure with respect to the difficult anatomic setting.

METHODS

 The present review provides an in-depth depiction and evaluation of the interventional methodology of the embolization of T2EL in the abdominal aorta with use of ethylene vinyl alcohol copolymer (EVOH). Complicating anatomic conditions are taken into account as well as technical and clinical success rates.

RESULTS

 Using the transarterial approach, there are at least 4 different pathways to access the nidus of a T2EL. CT-guided direct puncture of the aneurysm sac provides an alternative method of high technical success. EVOH with its slow solidification characteristics enables good control to achieve complete filling of the T2EL. During the intervention, however, it remains difficult to meet exactly the embolization endpoint, especially in large T2ELs.

CONCLUSION

 T2EL embolization using EVOH is an effective treatment with low major complication rates when conducted by skilled interventionists with detailed knowledge of diverse complex access routes.

KEY POINTS

  · Many roads lead to Rome to access the nidus of a T2EL including diverse complex transarterial pathways and direct aneurysm sac puncture.. · Ethylene vinyl alcohol co-polymer enables good control for slow filling of the nidus with low risk of major complications.. · Identification of the embolization endpoint remains difficult during the procedure and may result in secondary interventions.. · Successful T2EL embolization requires detailed knowledge of all access routes to the nidus and skilled handling of liquid embolics..

CITATION FORMAT

· Nolte-Ernsting C, Mecklenbeck F, Stehr A. Embolization of Type 2 Endoleaks in the Abdominal Aorta Using Ethylene Vinyl Alcohol Copolymer. Fortschr Röntgenstr 2021; DOI: 10.1055/a-1502-7883.

Intraoperative Findings of an Atypical Type II Endoleak from an Artery within the Aneurysmal Wall after Endovascular Aneurysm Repair

A 75-year-old man underwent emergent endovascular aortic repair for a ruptured abdominal aortic aneurysm. Two years later, computed tomography revealed aneurysm enlargement with endoleaks. Next, late open conversion was performed. Intraoperatively, we detected a spurting type II endoleak from an artery within the aneurysmal wall, which was unconnected to any branch vessels outside the aneurysm, and surgical ligation and sacotomy was performed uneventfully. To our knowledge, this is the first report to intraoperatively identify a type II endoleak from an artery within the aneurysm wall. Even for atypical type II endoleak, such as this case, open surgical repair should be effective.

Transgraft embolization by using long needle for the treatment of type II endoleaks after endovascular abdominal aortic repair

We used a long custom needle (LCN) to improve transgraft embolization (TGE) in 10 reported cases that underwent TGE with LCN for type II endoleak (T2E) treatment after endovascular abdominal aortic aneurysm repair. TGE was performed with a LCN enabling the usage of microcatheter and embolization coils in 10 cases with T2E after endovascular abdominal aortic aneurysm repair. Embolization was successfully achieved in the nidus in all 10 cases. The aneurysmal sac diameter significantly decreased by TGE, and none of the 7 of 10 cases exhibited recurrence of sac expansion or T2E throughout the 2-year follow-up period.

Mid-term Outcomes and Predictors of Transarterial Embolization for Type II Endoleak After Endovascular Abdominal Aortic Aneurysm Repair

PURPOSE

To evaluate the mid-term outcomes of transarterial embolization (TAE) for type II endoleak after endovascular abdominal aortic aneurysm repair (EVAR) and investigate the predictors of sac enlargement after embolization.

MATERIALS AND METHODS

We conducted a retrospective analysis of 55 patients [48 men and 7 women, median age 79.0 (interquartile ranges 74-82) years] who underwent TAE for type II endoleak from 2010 to 2018. The aneurysmal sac enlargement, endoleaks, aneurysm-related adverse event rate, and reintervention rate were evaluated. Patients' characteristics and clinical factors were evaluated for their association with sac enlargement.

RESULTS

Fifty-five patients underwent TAE with technical success and were subsequently followed for a median of 636 (interquartile ranges 446-1292) days. The freedom from sac enlargement rates at 1, 3, and 5 years was 73.2%, 32.0%, and 26.7%, respectively. After initial TAE, the recurrent type II, delayed type I, and occult type III endoleak were identified in 39 (71%), 5 (9%), and 3 (5%) patients, respectively. Although a patient had aorto-duodenal fistula, there was no aneurysm-related death. The freedom from reintervention rates was 84.6%, 35.7%, and 17.0%, respectively. In the multivariate analysis, sac diameter > 55 mm at initial TAE (hazard ratios, 3.23; 95% confidence intervals, 1.22-8.58; P < 0.05) was a significant predictor of sac enlargement.

CONCLUSION

TAE for type II endoleak was not effective in preventing sac enlargement, and reinterventions were required among the mid-term follow-up. The sac diameter > 55 mm at initial TAE was a significant predictor of sac enlargement.

Atypical Type 2 Endoleak from an Artery Supplying the Psoas Major Muscle Following Endovascular Repair in a Case of Isolated Common Iliac Artery Aneurysm

In this report, we present a rare case of type 2 endoleak (T2EL) from an artery supplying the psoas major muscle, following an endovascular repair of a common iliac artery aneurysm (CIAA). A 79-year-old male underwent endovascular aneurysm repair (EVAR) for the right isolated CIAA using stent graft, with embolization of the ipsilateral internal iliac artery. The aneurysm was stable for 2 years, after which a follow-up CT revealed a 5 mm increase in the CIAA diameter and an endoleak of unknown origin. Conventional and CT angiographies revealed the source to be a branch from the ipsilateral deep circumflex iliac artery supplying the psoas major muscle that had developed an anastomosis at its terminal end with the vasa vasorum at the CIAA. Transarterial embolization of T2EL using glue was performed successfully, following which the T2EL disappeared.