The diagnostic and treatment challenge of type IIIb endoleaks

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.

Treatment of a Delayed Type IIIb Endoleak 20 Years Post EVAR With Inverted Contralateral Limb Custom-Made Device: A Case Report

PURPOSE

Type III endoleak can be difficult to distinguish from Type I endoleak. Depending on the stent graft anatomy, the use of standard bifurcated endografts may not be technically feasible, and patients may have to be subject to an aorto-uni-iliac repair with femoral-femoral bypass or open surgery.

CASE REPORT

We report a case of an 86-year-old male who had a Type IIIb endoleak 20 years post EVAR which was characterized on angiography to be from a hole close to the bifurcation limb origin. The initial Talent (Medtronic, Santa Rosa, California) device had a 50 mm main body common trunk, which was not amenable to treatment with standard devices. He was successfully treated with a custom-made device with an inverted contralateral limb.

CONCLUSIONS

Our case highlights the need for lifelong surveillance post EVAR as endoleak may present decades post initial EVAR. It also demonstrates that many Type III endoleak which were otherwise deemed unsuitable for treatment with standard devices may potentially be treatable with custom-made device (CMD). This solution preserves a percutaneous option in a now older person which avoids surgical bypass. Further studies are required to establish the durability of this treatment and survey for recurrence.

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.

Diagnosis and relining techniques for delayed type IIIB endoleaks with the second-generation AFX endograft

Type IIIB endoleaks resulting from endograft fabric tear are an uncommon but serious late complication of endovascular aortic aneurysm repair. The Strata fabric used in the earlier generation AFX endograft (updated to Duraply in October 2014) has been associated with an increased frequency of these events. Herein we report on two patients exhibiting delayed type IIIB endoleaks after AFX device insertion to treat an abdominal aortic aneurysm and discuss optimal relining techniques.