The Challenge of Endoleaks in Endovascular Aneurysm Repair (EVAR): A Review of Their Types and Management

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta above 3 cm or 50% greater than the segment above. It is a dangerous condition accounting for a substantial number of deaths per year and increasing at an alarming rate. Various factors come into play in the development of AAAs, which this study has elaborated on, including smoking and old age, demographics, and comorbid conditions. Endovascular aneurysm repair (EVAR) is a newer treatment modality used for AAAs in which an endograft device is placed into the aorta, thereby creating a bypass tract from the aneurysm and generating flow mimicking that of the natural aorta. It is minimally invasive and associated with less postoperative mortality and reduced hospital stay. However, EVAR is also associated with significant postoperative complications, including endoleaks, which were reviewed in depth. Endoleaks are postprocedural leaks into the aneurysm sac that are usually identified immediately after graft placement and indicate treatment failure. They are of five subtypes, categorized according to their mechanism of development. The most common type is type II endoleaks, and the most dangerous is type I endoleaks. Each subtype has multiple management options with varying rates of success. Prompt identification along with appropriate treatment of endoleaks can lead to better postoperative outcomes and improved quality of life for patients.

Outcome and technical evolution of type 2 endoleak embolization with ethylene-vinyl-alcohol copolymer

PURPOSE

This study aims to evaluate the safety and efficacy of novel approaches to type 2 endoleak access for the purpose of embolization using ethylene-vinyl-alcohol copolymer (EVOH) in patients with abdominal aortic aneurysm (AAA) sac expansion post endovascular abdominal aortic repair (EVAR).

METHODS

A retrospective review of 43 consecutive patients (mean age = 80.2 ± 6.7 years) who underwent 52 embolization procedures for type 2 endoleaks using EVOH was performed at a single institution. Catheterization of the endoleaks was achieved using the transarterial (TA) and direct translumbar approaches (DTL), in addition to the novel direct transabdominal (DTA) and perigraft (PG) approaches. Endpoints included technical success of endoleak catheterization, technical success of endoleak embolization, endoleak persistence, endoleak recurrence, AAA sac area change, and adverse events.

RESULTS

The TA, DTL, DTA, and PG approaches were used 25, 2, 14, and 19 times respectively, including nine procedures where a combination of approaches was used. The technical success rate of endoleak embolization was 98%. Five patients developed recurrent type 2 endoleaks, while five patients developed a type 1 endoleak. The persistent endoleak rate at a mean initial follow-up of 3 months was 34%. At a mean follow-up of 18 months, 58% of patients demonstrated absence of an endoleak, and 71% showed freedom from AAA sac enlargement. No major adverse events were recorded.

CONCLUSION

The DTA and PG approaches were safe and effective in this cohort of patients undergoing embolization of type 2 endoleaks with EVOH.

Midterm Outcomes of Endoleak Type 2 Embolization after Endovascular Aortic Aneurysm Repair Using a Neurointerventional Approach

BACKGROUND

Type 2 endoleaks (T2ELs) have been considered a benign condition and intervention is recommended when they are associated to sac expansion. The aim of this study was to report on T2EL embolization midterm outcomes, using neurointerventional material.

METHODS

A single-center retrospective analysis of consecutive patients treated with transarterial embolization, using neurointerventional material, for T2EL after standard endovascular aortic aneurysm repair (EVAR) between January 01, 2017 and July 30, 2022, was undertaken. Primary outcome was technical success and secondary outcome was T2EL recurrence during follow-up.

RESULTS

Twenty six patients [92.3% males, mean age 73.9 ± 7.7 years] were included. The median time between EVAR and T2EL diagnosis was 12 months (range: 1-84 months). In 38.5% of patients, T2EL was detected at first month after EVAR. The time to embolization was 18 months (range: 1-96 months). In 42.3% of cases, a patent inferior mesenteric artery was suspected to relate to T2EL formation while in 42.3% of cases, a lumbar artery. Twelve procedures (38.4%) were performed using coils and Onyx and 13 (50%), using only Onyx. Technical success was 84.6%. The mean follow-up was 24 months (range: 1-60 months), including 20 patients. In 30% of cases, an T2EL recurrence was detected. Three patients (11.5%) underwent secondary embolization.

CONCLUSIONS

Transarterial embolization for T2EL, using neurointerventional material, provided acceptable technical success and T2EL recurrence rates at 2 years of follow-up. Longer follow-up data would further estimate the durability of the technique.

A systematic review of the current status of interventions for type II endoleak after EVAR for abdominal aortic aneurysms

OBJECTIVE

To study the mid- and long-term outcomes of type II endoleak treatment after EVAR and the technical aspects of different techniques to exclude endoleaks which different embolic agents.

METHODS

A systematic review was performed using the approach recommended by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for meta-analyses of interventional studies. The comprehensive search was conducted using the following database: MEDLINE, EMBASE, and the Cochrane Library. Patient characteristic, intervention approaches, embolic agents, and results at mid and long term follow up were studied.

RESULTS

A total of 6 studies corresponding to a total of 141 patients fulfilled the inclusion criteria with a mean age of 73-78.6 years and a mean duration of follow up varying from 25 to 42 months. There were different techniques for embolization used (translumbar, transarterial, and transcaval approach) with various types of embolic agents. In all studies, the indication for embolization of the type II endoleaks was sac enlargement of more than 5 mm. A wide range of technical success rate was reported regardless of the intervention strategy being used (17,6%-100%). The overall technical success rate of all studies was 62%.

CONCLUSION

This systematic review shows that there is a wide variety of techniques to exclude a persistent type II endoleak. Different kinds of embolic agents have be used. Due to a lack of peer reviewed data on longterm follow-up, it was not possible to come to recommendations what treatment would be the best for a durable exclusion of a persistent type II endoleak after an initially successful EVAR. There remains an urgent need for proper executed studies, either randomized or with close observation in relation to longer follow-up.

Factors Influencing Clinical Success Following Endovascular Treatment of Type II Endoleaks

PURPOSE

To compare long-term outcomes of transarterial (TA) and translumbar (TL) embolization of type II endoleaks (T2E) following EVAR, as well as factors that predict clinical success.

METHODS

129 (mean age, 71.4y; range, 53-95) with T2E referred for embolization from August-2003 to December-2017 were retrospectively reviewed. One-hundred-eighty procedures were performed via TA (n = 139) and TL (n = 41) approaches, with 37 patients undergoing 51 reinterventions. Clinical success was defined as absence of endoleak and/or absence of aneurysm sac enlargement on follow-up imaging. Medical comorbidities, procedural data, embolic agents used, presence of successful sac embolization, and 30-day morbidity and mortality data were collected.

RESULTS

TL approaches had higher technical success (41/41 vs.122/139, p = .014). Clinical success rates were 52% (N = 58/111) and 62% (N = 23/37) for TA and TL procedures respectively (p = .34). Looking at all procedures, sac embolization using n-butyl cyanoacrylate glue had higher clinical success compared to other embolic agents (p = .017-.037). Successful sac access was a strong predictor of success for TA procedures (46/78 vs.12/33, p = .0379). 30-day complication rates were similar between TA (5.8%) and TL (4.9%) approaches. There was 1 death secondary to graft infection following TA embolization.

CONCLUSIONS

Overall clinical success of TA and TL embolization when considering re-interventions is high. n-butyl cyanoacrylate glue had significantly higher success than other embolic agents (p = .017-.037). Successful sac access was associated with success for TA procedures.

Secondary Endoleak Management Following TEVAR and EVAR

Endovascular abdominal and thoracic aortic aneurysm repair and are widely used to treat increasingly complex aneurysms. Secondary endoleaks, defined as those detected more than 30 days after the procedure and after previous negative imaging, remain a challenge for aortic specialists, conferring a need for long-term surveillance and reintervention. Endoleaks are classified on the basis of their anatomic site and aetiology. Type 1 and type 2 endoleaks (EL1 and EL2) are the most common endoleaks necessitating intervention. The management of these requires an understanding of their mechanics, and the risk of sac enlargement and rupture due to increased sac pressure. Endovascular techniques are the main treatment approach to manage secondary endoleaks. However, surgery should be considered where endovascular treatments fail to arrest aneurysm growth. This chapter reviews the aetiology, significance, management strategy and techniques for different endoleak types.

Techniques and future perspectives for the prevention and treatment of endoleaks after endovascular repair of abdominal aortic aneurysms

The presence of endoleaks remains one of the main drawbacks of endovascular repair of abdominal aortic aneurysms leading to the increase of the size of the aneurysmal sac and in most of the cases to repeated interventions. A variety of devices and percutaneous techniques have been developed so far to prevent and treat this phenomenon, including sealing of the aneurysmal sac, endovascular embolisation, and direct sac puncture. The aim of this review is to analyse the indications, the effectiveness, and the future perspectives for the prevention and treatment of endoleaks after endovascular repair of abdominal aortic aneurysms.

Results of Transarterial Embolization for Treating Type 2 Endoleaks: A Single-Center Experience

BACKGROUND

Type 2 endoleaks (T2Es) are the main cause of reintervention after endovascular repair of abdominal aortic aneurysms (EVAR). The objective of this study is to quantify success rates of T2E treatment.

METHODS

This study involves a retrospective analysis of a prospectively maintained database containing data on all consecutive patients treated for a T2E between 2003 and 2017 in a single center. Technical success was defined as absence of endoleak in the final angiographic control after treatment. Clinical success was defined as absence of sac growth over 5 mm in the contrast-enhanced computed tomography performed a year thereafter. Statistics included Kaplan-Meier survival estimates.

RESULTS

A total of 528 elective EVARs were performed in the period. Thirty-six of these (6.8%) developed a T2E requiring reintervention, a median of 37.9 months after EVAR. Twenty-five percent of the treatments were performed more than 5 years after intervention. Twenty-eight of the 36 treatments were performed via transarterial embolization. For this technique, technical success was 71.4% and clinical success was 62.5%. A subsequent reintervention was required in 35.7% of patients. In this cohort, the rate of aneurysm rupture was 10.7% (n = 3/28), open surgical conversion was needed in 2 of 28 cases (7.1%), and rate of aneurysm-related death was 14.3% (n = 4/28) over follow-up.

CONCLUSIONS

A high percentage of patients are at risk of adverse outcomes after T2E treatment. Strict imaging follow-up is still needed in this population.

Transcatheter embolization with Squid, combined with other embolic agents or alone, in different abdominal diseases: a single-center experience in 30 patients

Background

Squid, as Onyx, is an ethylene-vinyl alcohol copolymer (EVOH)-based liquid embolic agent developed for neuroradiologic interventions with poor application in abdominal district. Our aim was to evaluate safety, complications, and efficacy of transcatheter embolization using the two available formulations Squid-18 and 12, in 30 patients affected by different abdominal diseases.

Results

Transcatheter embolization with Squid, combined with other embolic agents, as poly vinyl alcohol (PVA) particles, coils and amplatzer plugs, or alone (type 2 endoleak), was performed in 30 patients, as follows: 10 portal vein embolizations (PVEs), 6 arteriovenous malformations (AVMs), 5 visceral artery aneurysms (VAAs), 4 type 2 endoleaks, 3 preoperative embolizations, 1 acute arterial bleeding, 1 female varicocele. Squid was always administered using dimethyl sulfoxide (DMSO) compatible microcatheters. Technical success, 30-day clinical success and complications were assessed.

Technical success was 90%. 3 patients (2 AVMs, 1 VAA) required re-intervention successfully performed in all cases. Major complications, cases of microcatheter entrapment and DMSO-related poor pain control were not recorded. 30-day clinical success was 93.3%: in 2 patients submitted to PVE a sufficient future liver remnant (FLR) hypertrophy was not achieved.

Conclusion

Squid was successfully used with low complication rate in many abdominal diseases showing a valid embolic action either combined with other embolic agents or alone in type 2 endoleak. The availability of different formulations (Squid-18 and Squid-12) variable for viscosity makes Squid preferable to Onyx as EVOH-based liquid embolic agent, even though comparable studies in different abdominal districts with a larger cohort of patients will be necessary.

Editor's Choice - Systematic Review and Meta-Analysis of the Outcome of Treatment for Type II Endoleak Following Endovascular Aneurysm Repair

OBJECTIVES

The efficacy and need for secondary interventions for type II endoleaks following endovascular abdominal aortic aneurysm repair (EVAR) remain controversial. This systematic review aimed at investigating the clinical outcomes of different type II endoleak treatments in patients with a persistent type II endoleak after EVAR.

DATA SOURCES

Embase, Medline via Ovid, Web of Science Core Collection, the Cochrane CENTRAL, and Google Scholar.

REVIEW METHODS

This systematic review was performed in accordance with the PRISMA Statement. Outcomes of interest were technical and clinical success, change in sac diameter, complications, need for additional interventions, abdominal aortic aneurysm (AAA) rupture, and (AAA related) mortality. Meta-analyses were performed with random effects models.

RESULTS

A total of 59 studies were included, with a cumulative cohort of 1073 patients with persistent type II endoleak. Peri-operative complications following treatment of type II endoleaks occurred in 3.8% of patients (95% CI 2.7-5.2%), and AAA related mortality was 1.8% (95% CI 1.1-2.7%). Overall technical success was 87.9% (95% CI 83.1-92.1%), while clinical success was 68.4% (95% CI 61.2-75.1%). Among studies detailing sac dynamics, decrease or stable sac, with or without resolution, was achieved in 78.4% (95% CI 70.2-85.6%). Changes in sac diameter following type II endoleak treatment were documented in 157 patients to at least 24 months. Within this group an actual decrease in sac diameter was reported in only 27 of 40 patients.

CONCLUSION

There is little evidence supporting the efficacy of secondary intervention for type II endoleaks after EVAR. Although generally safe, the lack of evidence supporting the efficacy of type II endoleak treatment leads to difficulty in assessing its merits.