Incidence of stent graft failure from type IIIB endoleak in contemporary endovascular abdominal aortic aneurysm repair

Exploring Type IIIb Endoleaks: A Literature Review to Identify Possible Physical Mechanisms and Implications

Endoleaks are common complications following endovascular aneurysm repair (EVAR). They can be classified into low-pressure and high-pressure endoleaks. High-pressure endoleaks, which include Type I and Type III endoleaks, pose a significant risk of rupture and require urgent treatment. The aim of our study is to review published case reports and case series to assess the impact of Type IIIb endoleaks in EVAR and to identify possible mechanisms contributing to these endoleaks. This review targeted case reports and case series published between January 1998 and December 2022. A total of 62 case reports and case series were identified, encompassing 156 patients with Type IIIb endoleaks. Data collection was performed by three consultants who thoroughly discussed each report before registering it into an analyzable data set. Our analysis revealed that, beyond material imperfections, certain endograft configurations or conformations, endograft redundancy, and the physical forces acting on the grafts may lead to increased stress on specific parts of the endografts, potentially exceeding their design limits. Factors contributing to redundancy and unfavorable conformation of the endograft include secondary interventions for any cause (such as other types of endoleaks), EVAR performed outside the instructions for use (IFUs), endograft migrations, or larger initial aneurysm diameter.

Type III Endoleak Incidence and Outcomes in Endovascular Aortic Repair: Comparison of Anatomical and Proximal Fixation Devices

PURPOSE

To evaluate the influence of endograft fixation type on the incidence, treatment, and outcomes of type III endoleaks (TIIIELs).

MATERIALS AND METHODS

Abdominal aortic aneurysms (AAAs) treated with bifurcated endografts between 1994 and 2020 were prospectively collected and reviewed. The endograft included were classified as "Anatomical Fixation" (AF) (Powerlink [Endologix] and AFX [Endologix]) or "Proximal Fixation" (PF). The primary outcome was the incidence of TIIIEL over time, stratified by fixation type. Secondary outcomes included between-group comparisons of baseline characteristics, intraoperative details during TIIIEL correction, and survival analysis after TIIIEL diagnosis.

RESULTS

A total of 2065 endovascular aneurysm repairs were performed: 872 (42.2%) with AF and 1193 (57.8%) with PF devices. The estimated incidence of TIIIEL at 1, 5, and 10 years was 0.4%, 4.2%, and 7.3%, and 0.5%, 3.2%, and 4.6% for AF and PF, respectively (p=0.157), and fixation type was not associated with TIIIEL development in the competing risk regression model (p=0.101). The cumulative overall survival rate in patients diagnosed with TIIIEL did not differ significantly between the groups (p=0.077). The rate of recurrent TIIIELs was significantly lower in the AF group (7.1% vs 22.7%; p=0.044); however, no significant difference was found in secondary reintervention between the two groups (11.9% vs 27.3%, p=0.074). Patients with angulated and calcified aortic neck (SHR 3.4, 95% CI 1.2-9.6, p=0.022) and larger aneurysms (SHR 1.2; 95% CI 1.1-1.3; p<0.001) had a higher risk of TIIIEL. Likewise, the use of three or more endograft components increased the risk of TIIIEL by 3.1 times (SHR 3.1; 95% CI 1.7-5.4; p<0.001).

CONCLUSIONS

The occurrence of TIIIELs was not affected by the type of endograft fixation. For larger abdominal aortic aneurysms (AAAs) and aneurysms with angulated and calcified aortic necks, there is a higher likelihood of developing TIIIELs during follow-up, regardless of the endograft type used.

CLINICAL IMPACT

The type of fixation does not influence the incidence of TIII ELs. EVAR in larger AAAs and aneurysms with angulated and calcified aortic necks have a higher risk of developing TIII EL. Moreover, the risk of TIII EL is considerably increased by the use of three or more modular components.

Serious Failure Modes After EVAR Are Device Specific

OBJECTIVES

Type I and III endoleaks following endovascular aneurysm repair (EVAR) can lead to catastrophic events that require major re-interventions. We reviewed our experience with aortic endograft re-interventions for type I and III endoleaks and other serious failures among different devices.

METHODS

We retrospectively reviewed patients with a prior EVAR who underwent open conversion (OC) or major endovascular intervention (MEI) (re-lining, cuff/limb extension, parallel graft) for type I/III endoleaks at our institution from 2002 to 2019. Baseline characteristics, procedural details, re-interventions, and outcomes were collected.

RESULTS

A total of 229 patients (194 men) underwent re-interventions for type I and III endoleaks after EVAR (90 OC, 139 MEI) for devices implanted between 1997 and 2019. Average age at re-intervention was 78±8.5 years. A total of 135 (59%) were implanted at our institution, whereas 93 (41%) were referred. Median time to re-intervention was 4 years with 25% to 75% interquartile range (IQR) of 2.2-6.6 years. There was no significant difference in baseline demographics or type of re-interventions (OC/MEI) between device types. 42/229 (18%) presented with ruptured aneurysms, 20/229 (9%) were symptomatic, whereas the rest presented with asymptomatic radiographic findings. Type 1A endoleak was present in 146/229 (63.8%-72 with proximal migration), type IB in 46/229 (20.1%), type IIIA in 37/229 (16.6%), type IIIB in 15/229 (6.5%), and persistent aneurysm sac growth with no radiographic evidence of an endoleak in 6/229 (2.6%). Devices included most commercial products: AFX, Excluder, AneuRx, Ancure, Endurant, and Zenith. A smaller number of investigational devices accounted for the rest. Type 1A endoleak was the most common indication for re-intervention among all devices except for AFX and ancure devices, proximal migration was a frequent presentation with AneuRx. AFX devices more frequently presented with a type III and ancure devices more frequently presented with a type IB endoleak.

CONCLUSIONS

Serious failure modes after EVAR differ between endografts and occur throughout the follow-up period. This is important to guide targeted interrogation of surveillance studies and follow-up schedules, even for discontinued devices, as well as comparisons between various series and estimation of EVAR failure rates.

CLINICAL IMPACT

Surveillance after EVAR is critical for long term success of the repair, understanding of the differential modes of failure of every graft available is important in the longitudinal evaluation of these endografts. Equally important is the understanding of the modes of failure of legacy endografts that are no longer on the market but still being followed, in order to be able to tailor a surveillance regiemn and the evntual repair if needed.

Editor's Choice -- Type IIIb Endoleaks: Fabric Perforations of Explanted New Generation Endoprostheses

OBJECTIVE

To analyse explanted endografts (EGs) and describe fabric degradation responsible for type IIIb endoleaks.

METHODS

As part of the European collaborative retrieval programme, 32 EGs with fabric defects on macroscopic evaluation were selected. The explanted EGs were processed and studied based on the ISO 9001 certified standard protocol. It includes instructions on the collection, transportation, cleaning, and examination of explanted material. The precise analysis was performed with a digital microscope of 20 - 200 times magnification. Possible perforation mechanisms were assessed in stress tests.

RESULTS

The median time to explantation of the 32 EGs was 54 months. The explants included 65 separate EG modules, with 46 (70.8%) having a combined 388 fabric perforations. Each EG had a median of 4.79 mm2 (interquartile range [IQR] 9.86 mm2) of cumulated hole area (an average of 0.13% of an EG's area). There were 239 (61.6%) expanded polytetrafluoroethylene (ePTFE; 11 EGs) and 149 (38.4%) polyethylene terephthalate (PET; 21 EGs) fabric ruptures, with no difference in hole distribution between these types of material. Overall, 126 (32.5%) stent related and 262 (67.5%) non-stent related fabric perforations were identified. Perforations caused by fabric fatigue in ePTFE (151, 63.2%) and material kinking in PET (41, 27.5%) were the most common. The stent related perforations were larger in size (0.80 mm2) than non-stent related perforations (0.19 mm2); p < .001. Wider interstent spaces and prolonged implantation duration were associated with an increased risk of stent related perforation development; p < .001 and p = .004, respectively. Large stent related perforations were also detected in the short term, suggesting mechanical issues as underlying causes.

CONCLUSION

The fabric of EGs may degrade and lead to the development of perforations. The largest perforations are stent related. Their occurrence and size depend on the implantation time and the EG shape affected by arterial tortuosity. The conclusions are limited to the samples from a select explant group.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Traumatic Endograft Fracture With Subsequent Type IIIb Endoleak

Abdominal aortic aneurysm (AAA) repair is commonly treated via endovascular aneurysm repair (EVAR). A known complication of EVAR is an endoleak: types I to IV. Type III endoleaks have been shown to have a relative risk of 8.95 for late rupture requiring prompt treatment. These endoleaks have been found to be caused by over dilation of the main body causing graft fabric distortion, fractures of metallic struts, fabric wear from chronic micromotion, fabric tears, and suture breakage. We present a case of traumatic EVAR fracture with subsequent type IIIb endoleak after blunt abdominal trauma. This highlights the need for close evaluation of endografts after abdominal trauma. These traumatic events can lead to traumatic fracture of endografts creating endoleaks that if not treated promptly can lead to rupture.

Giant Sac Growth: A Hybrid Approach to Treat a Misdiagnosed Late Type IIIb Endoleak

Introduction

Endoleaks are a common complication following endovascular aneurysm repair, yet type IIIb are rare, especially with newer devices, and associated with high morbidity due to repressurisation of the sac. As endografts are used in patients with longer life expectancy, late type IIIb endoleaks are to be expected. This is a report of a giant common iliac aneurysm resulting from a misdiagnosed type IIIb endoleak.

Report

An 85 year old man with history of right common iliac artery aneurysm, treated in 2003 with an EXCLUDER AAA Endoprosthesis (WL Gore, Flagstaff, AZ, USA) with iliac limb extension into the external iliac artery, presented at the emergency department with abdominal pain, hypotension, and syncope. He had a known endoleak, unsuccessfully treated by relining the right iliac stent graft overlap zones for a suspected type IIIa endoleak (2009), coil embolisation, and computed tomography (CT) guided thrombin injection of the aneurysmatic sac for a type II (2010), none of which managed to treat the cause with continuous aneurysm growth. The patient refused further treatments, but agreed to maintain surveillance. At admission, CT angiography showed common iliac aneurysm (185 × 134 mm) sac rupture without a visible endoleak. Resuscitative endovascular balloon occlusion of the aorta (REBOA) technique was performed to obtain haemodynamic control, then the aneurysm was approached through a midline incision. A type IIIb endoleak was identified due to a fabric tear on the right iliac limb extension. Suture was attempted without success, then relining of the lesion with an Endurant II Limb (Medtronic, Minneapolis, MN, USA) was performed, which managed to repair the endoleak.

Discussion

Type IIIb endoleaks are uncommon and underdiagnosed due to fabric defects being too small or leaking intermittently. They can mimic other types of endoleaks and may cause aneurysm growth and rupture. One should consider this type of endoleak if previous treatments for other types were unsuccessful.

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.

Elucidating the role of the AFX2 endograft in endovascular treatment of aortic pathology

OBJECTIVE

The purpose of this study is to elucidate the role of the AFX2 platform in the endovascular treatment of aortic pathology.

METHODS

All procedures by a single surgeon resulting in implantation of a bifurcated unibody stent graft were retrospectively reviewed. Indications for selection of the AFX2 endograft in each case were evaluated. Aortic anatomy was determined via review of pre-operative computed tomography (CT) scans. Cumulative event probabilities for endoleak, reintervention, and mortality were estimated. Patient and procedural details were described using mean, standard deviation, medians, and interquartile range (IQR). Kaplan-Meier survival analysis estimated freedom from mortality and reintervention. Cumulative incidence probabilities were calculated as one minus the Kaplan-Meier estimator.

RESULTS

Between March 2018 and December 2020, the author (NN) used 142 aortic endografts in 142 patients. Of these, 46 (32.4%) were AFX2 endografts and the remaining were modular bifurcated devices, predominantly Medtronic Endurant II and Terumo Treo. No AFX-Strata or AFX-Duraply devices were placed. Amongst the patients who received an AFX2, mean age was 71.3 +/- 9.8 years with 84.8% male. Median operative time was 116 (86-166) minutes, with contrast dose of 79 (41-120) milliliters and fluoroscopy time of 12 (8.6-18) minutes. Overall, 78.3% (n=36) of AFX2 devices were placed in aortas with maximum true lumen diameter <5.0cm. Median postoperative follow-up was 1.7 years (IQR 1.0-2.4 years), with a maximum follow-up of 3.6 years. There was 1 patient lost to follow-up at 5 months. The 2-year incidence of type II endoleak, reintervention, and all-cause mortality was 12.7% (95% CI, 0-29.6%), 2.2% (95% CI, 0-6.3%), and 11.3% (95% CI, 0.1-2.1.2%), respectively. There were no type I or III endoleaks.

CONCLUSION

The AFX2 endograft plays a safe and effective role in treatment of infrarenal aortic pathologies that may be otherwise more technically challenging for traditional modular, bifurcated devices.

Type IIIb endoleak due to stent suture line fabric breakage in the Endurant stent graft: a case report

Background

Early type IIIb endoleak is a very rare complication of endovascular aneurysm repair (EVAR).

Case presentation

An 87-year-old man was diagnosed with infrarenal abdominal aortic aneurysm. The patient underwent EVAR using the Endurant stent graft. Postoperative color duplex ultrasound revealed a regular row of pulsatile blood flow from the main body and left leg. The blood flow appeared to be bleeding from the stent suture lines because of its regularity. Type IIIb endoleak was suspected due to stent suture line fabric breakage but was not treated surgically or endovascularly because of the patient’s poor general health status. Six months later, contrast-enhanced CT demonstrated a deformation and enlargement of the aneurysm sac as well as an oozing of the contrast medium on the main body and left limb. Thereafter, he died of a subdural hematoma due to a fall. Autopsy showed no visible abnormal erosion or holes on the graft fabric, suggesting that suture line fabric breakage may have existed during the manufacturing process.

Conclusions

Although rare, type IIIb endoleaks can occur even in the perioperative period after EVAR. Early type IIIb endoleaks may not resolve spontaneously and should be treated promptly, if possible.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40792-022-01415-8.

[Endoleaks in endovacular infrarenal abdominal aortic aneurysm repair. (Part II)]

Searching for literature data was performed in the PubMed, Scopus and eLIBRARY databases. In the second part, we considered modern classifications of endoleaks type 3, 4 and 5 after endovascular infrarenal abdominal aortic aneurysm repair, etiology, risk factors, classification of endoleaks. Modern data on effectiveness of their treatment by various methods are presented.

Influences of Stent Design on In-Stent Restenosis and Major Cardiac Outcomes: A Scoping Review and Meta-Analysis

Thanks to the developments in implantable biomaterial technologies, invasive operating procedures, and widespread applications especially in vascular disease treatment, a milestone for interventional surgery was achieved with the introduction of vascular stents. Despite vascular stents providing a solution for embolisms, this technology includes various challenges, such as mechanical, electro-chemical complications, or in-stent restenosis (ISR) risks with long-term usage. Therefore, further development of biomaterial technologies is vital to overcome such risks and problems. For this purpose, recent research has focused mainly on the applications of surface modification techniques on biomaterials and vascular stents to increase their hemocompatibility. ISR risk has been reduced with the development and prevalent usage of the art technology stent designs of drug-eluting and biodegradable stents. Nevertheless, their problems have not been overcome completely. Furthermore, patients using drug-eluting stents are faced with further clinical challenges. Therefore, the bare metal stent, which is the first form of the vascular stent technology and includes the highest ISR risk, is still in common usage for vascular treatment applications. For this reason, further research is necessary to solve the remaining vital problems. In this scoping review, stent-based major cardiac events including ISR are analyzed depending on different designs and material selection in stent manufacturing. Recent and novel approaches to overcome such challenges are stated in detail.

A preliminary analysis of late structural failures of the Navion stent graft in the treatment of descending thoracic aortic aneurysms

OBJECTIVE

Patients in the Valiant Evo U.S. and international clinical trials had positive short-term outcomes; however, late structural failures, including type IIIb endoleaks have been recently discovered. Type IIIb endoleaks are serious adverse events because the repressurization of the aneurysm sac increases the risk of rupture. The purpose of the present study was to detail the imaging patterns associated with the structural failures with the aim of increasing awareness of failing graft presentation, early recognition, and prompt treatment.

METHODS

The Valiant Evo clinical trial was a prospective, single-arm investigation of a thoracic stent graft system. With the recent late structural failures, sites were requested to submit all available imaging studies to date to allow the core laboratory to assess for structural failures such as type IIIb endoleaks, stent ring fractures, and stent ring enlargement. Of the 100 patients originally enrolled in the trial from 2016 to 2018, the core laboratory assessed the imaging studies performed at ≥1 year for 83 patients.

RESULTS

No structural failures of the graft were reported through 1 year of follow-up. At 1 to 4 years, graft structural failures were detected in 11 patients with descending thoracic aortic aneurysms. Of the 11 patients, 5 had a type IIIb endoleak. Four of the five had imaging findings showing stent fractures consistent with the location of the graft seam and one had a type IIIb endoleak attributed to calcium erosion with no stent fracture or ring enlargement. Of the four patients with stent fracture in line with the graft seam, three underwent a relining procedure that successfully excluded the type IIIb endoleak. One of these three patients died 4 days later of suspected thoracic aortic rupture because the distal thoracic endovascular aortic repair extension had been landed in a previously dissected and fragile section of the aorta. The remaining six patients had had stent ring enlargement. One of the six patients had had persistent aneurysm expansion from the time of implantation onward and had died of unknown causes. The remaining five patients have continued to be monitored.

CONCLUSIONS

In the present preliminary analysis, the imaging patterns associated with type IIIb endoleaks, stent fractures, and stent ring enlargement appear to be related to the loss of seam integrity or detachment of the stent rings from the surface of the graft material. The imaging patterns we have detailed should be closely monitored using computed tomography angiography surveillance to allow structural failures to be promptly identified and treated.

Diagnostic Colour Duplex Ultrasound for Type IIIb Endoleak

Introduction

This report presents the treatment of an aortic endovascular aneurysm repair (EVAR) device failure, focusing on the use of colour duplex ultrasound (CDUS) to diagnose and confirm effective treatment of a type IIIb endoleak.

Report

An 89 year old man with a history of EVAR was transferred to the authors’ centre with complaints of abdominal pain and a pressure sensation behind the umbilicus. A previously stable 11 cm aneurysm sac was visualised on computed tomography angiography in addition to a newly suspected type IIIb endoleak, which was confirmed via CDUS. He underwent successful endovascular repair with a stent across the limb defect. The patient was discharged uneventfully and was followed for surveillance.

Discussion

Type IIIb endoleak is an underreported complication after EVAR. CDUS of type IIIb endoleak aided in localisation and characterisation of the graft failure, and confirmed successful endovascular treatment of the endoleak defect in the side limb. Locating the point of graft failure using CDUS preceding endovascular repair of type IIIb endoleaks guides interventions and repair outcomes. It is a rare opportunity to report a case of acute type IIIb endoleak with CDUS that definitively localised an endograft defect.

•

Safe, economic, and effective surveillance is imperative after EVAR.

•

Colour duplex ultrasound should be considered in the preoperative period to characterise the endoleak.

•

Colour duplex ultrasound can quantify flow velocity and direction in the setting of endoleak.

•

Colour duplex ultrasound may be used to confirm appropriate treatment of endoleak.