Type IIIb Endoleak Is an Important Cause of Failure Following Endovascular Aneurysm Repair

Stent Graft Migration Due to Structural Failure Nine Months After Thoracic Endovascular Aortic Repair Using Valiant Navion

Objective

This report presents a case of stent graft migration that was suspected to have occurred due to failure of the Valiant Navion device (Medtronic Inc., Santa Rosa, CA, USA). This case was rare because the broken device was removed from the living patient and examined directly.

Case report

A 69 year old man who had previously undergone thoracic endovascular aortic repair (TEVAR) with arch vessel debranching (axillo-axillary bypass with left common carotid artery bypass) for distal arch aneurysm experienced stent graft (SG) migration 9 months after the primary surgery. Total arch replacement was performed, and the migrated SG was removed. The broken stent ring and suture seams were then found. The patient was discharged on post-operative day 41 and followed up in the outpatient department.

Discussion

Stent graft migration is a relatively rare complication after TEVAR and associated with type I or III endoleak, which can result in serious outcomes. In this case, it was suspected that migration had occurred after TEVAR due to structural failure of the Valiant Navion device; similar cases have been reported previously, suggesting a structural problem with the device. Therefore, other patients treated with the Navion device in the future will require careful follow up.

Early-onset persistent type IIIb endoleak following incraft stent graft implantation in an abdominal aortic aneurysm patient

The type IIIb endoleak a rare complication of endovascular aneurysmal repair caused by endoprosthesis problem leading to deteriorating rupture, which is one of the major reasons for lifelong imaging surveillance. We report a case of an early-onset type IIIb endoleak from a tear in main body bifurcation (flow divider) area like crotch point tearing of pants following additional intervention to reduce immediate type Ia endoleak. Successful treatment of the endoleak was achieved by surgical conversion.

An unusual case of type IIIB endoleak after repeat thoracic endovascular aortic repair at acute-angled arch: A case of fabric tear by bare-metal stent

We report a case of an unusual case of type IIIB endoleaks after repeat thoracic endovascular aortic repair that was not visualized on computed tomography, first diagnosed during open conversion surgery, and successfully treated. A 69-year-old man had undergone repeat thoracic endovascular aortic repair for an enlarged thoracic aortic aneurysm six months before. His repeat computed tomography showed an acutely enlarged aneurysm, which had expanded from 80 to 96 mm in diameter, without any endoleaks. A type IIIB endoleak resulted from a small tear in fabric caused by a bare-metal stent of the previous endograft. The tip of the bare-metal of smaller outer endograft had penetrated a fabric portion of the inner larger endograft. The aneurysmal sac pressure was 58/46 mmHg, compared with a systemic pressure of 79/35 mmHg. The endografts were explanted and replaced with a vascular graft.

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.

Type IIIb Endoleak After Endovascular Aneurysm Repair Using the Zenith Stent Graft

We present 3 cases of type IIIb endoleak after endovascular aneurysm repair (EVAR) using the Zenith stent graft system. Type III endoleak, like type I endoleak, is a high-pressure, high-risk leak that increases sac pressure up to or even above arterial pressure, and is associated with an increased frequency of open conversions or risk of aneurysm rupture. Type IIIb endoleak is rare but there is much concern that the incidence of type IIIb endoleak is likely to increase hereafter; the mechanism of type IIIb endoleak is deterioration of graft fabric in conjunction with stent sutures. Type IIIb endoleak is difficult to diagnose before rupture. The possibility of type IIIb endoleak should be highly suspected when the continued growth of an excluded aneurysm sac without direct radiologic evidence is observed during follow-up. Type IIIb endoleak can be repaired by relining of the stent graft with additional stent grafts.

Type IIIB endoleak from stent suture lines of a thoracic endograft

We report a case of a patient with type IIIB endoleak after thoracic endovascular aortic repair that remained undetected by computed tomography and was first diagnosed during open conversion surgery. The aneurysm enlarged gradually from 60 to 78 mm without type I and type II endoleaks during 3 to 6 years after thoracic endovascular aortic repair. Type IIIB endoleaks from nitinol stent suture lines were detected, and the endograft was then explanted and replaced by a vascular graft.

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.

Abdominal aortic aneurysms

An abdominal aortic aneurysm (AAA) is a localized dilatation of the infrarenal aorta. AAA is a multifactorial disease, and genetic and environmental factors play a part; smoking, male sex and a positive family history are the most important risk factors, and AAA is most common in men >65 years of age. AAA results from changes in the aortic wall structure, including thinning of the media and adventitia due to the loss of vascular smooth muscle cells and degradation of the extracellular matrix. If the mechanical stress of the blood pressure acting on the wall exceeds the wall strength, the AAA ruptures, causing life-threatening intra-abdominal haemorrhage - the mortality for patients with ruptured AAA is 65-85%. Although AAAs of any size can rupture, the risk of rupture increases with diameter. Intact AAAs are typically asymptomatic, and in settings where screening programmes with ultrasonography are not implemented, most cases are diagnosed incidentally. Modern functional imaging techniques (PET, CT and MRI) may help to assess rupture risk. Elective repair of AAA with open surgery or endovascular aortic repair (EVAR) should be considered to prevent AAA rupture, although the morbidity and mortality associated with both techniques remain non-negligible.

Type IIIb endoleak after elective endovascular aneurysm repair: a systematic review

INTRODUCTION

The aim of this article is to investigate the presentation, etiology, management and outcomes of type IIIb endoleak after endovascular aneurysm repair (EVAR).

EVIDENCE ACQUISITION

Electronic bibliographic databases were searched to identify published reports of type IIIb endoleak after EVAR, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards.

EVIDENCE SYNTHESIS

In total 33 articles were identified reporting on a total of 50 patients spanning 19 years of EVAR (1998-2017). Some 11 device-types were used. The median time from implantation to intervention was 27 months (0-168). There was a significant aneurysm sac expansion in 69% of reported cases. Thirteen patients (26%) presented with aneurysm rupture. A definitive diagnosis of type IIIb endoleak made on computed tomographic angiography (CTA) in only 20% of cases. Proposed failure modes included suture breakage, graft erosion by stents, iatrogenic, graft infection and presumed manufacturing faults. Endoleak location was in the main body in 81% of reported cases. Almost one third (31%) of patients were treated with open repair. The remaining patients were treated with endovascular techniques or hybrid procedures. Some novel off-label endovascular solutions were proposed to maintain a bifurcated configuration. Thirty-day mortality in patients treated for aneurysm rupture was 50%. The 30-day mortality rate in non- rupture cases was 2% (endovascular 0% treatment, open 2%).

CONCLUSIONS

Type IIIb endoleak is a serious condition associated with a significant risk of rupture. Definitive diagnosis is challenging and has been described in almost all conventional devices. Most patients can be treated successfully by endovascular means, though maintaining a bifurcated configuration may require non-standard techniques or off-label use.

Parallel placement of Excluder legs for treatment of type IIIb endoleaks caused by fabric tear after endovascular aneurysm repair

A total of 576 patients underwent endovascular aneurysm repair using main body devices for treatment of abdominal aortic aneurysms or iliac artery aneurysms. During follow-up, type IIIb endoleaks caused by fabric tear occurred in six patients (1.0% [6/576]). The device used was Zenith (Cook Medical, Bloomington, Ind) in five cases and Talent (Medtronic, Santa Rosa, Calif) in one case. All endoleaks were close to the flow divider of the main body devices. The distance between the lower renal artery and the top end of the contralateral leg was 53 ± 14 mm. Bell-bottom-shaped Excluder (W. L. Gore & Associates, Flagstaff, Ariz) legs were placed parallel from the top of the main body device through both legs to treat these endoleaks. In two patients, coil embolization was required to treat gutter endoleaks. Postoperative computed tomography showed the obliteration of type IIIb endoleaks in all patients. Our technique may be an acceptable method for treatment of type IIIb endoleaks, especially when they occur near the flow divider.

Intraoperative Type IIIb Endoleak after Endograft Deployment during EVAR

Type IIIb endoleak usually occurs years after the initial endograft implantation, and the cause is the chronic fatigue of the endograft. This rare case describes a type IIIb endoleak, appearing immediately after deployment of a new generation low-profile stentgraft and highlights the diagnostic and treatment challenges associated with the type IIIb endoleak. A 74-year-old man underwent elective EVAR for an infrarenal abdominal aortic aneurysm. A type IIIb endoleak near to the flow divider due to a fabric defect was diagnosed. The endoleak was successfully treated by endovascular positioning of a converter stent graft followed by the occlusion of the left limb with an iliac occluder and a femoro-femoral crossover bypass surgery. The ultrasound scan after 4 weeks showed no sign of endoleak. Occurrence of a type IIIb endoleak immediately after deployment is extremely rare. Based on the convenience of the intraoperative procedure and the anatomic characteristics of the aneurysm, we assume that the fabric defect might have occurred during loading of the endograft and subsequent confinement in the delivery catheter. We cannot definitely rule out the possibility of fabric damage induced by low-pressure balloon instrumentation. In case of a suspicion of a type IIIb endoleak, bilateral balloon occlusion of both limbs followed by antergrade aortography will help to identify the leak. In case the defect is near to the flow divider, aortouniliac grafting followed by femoro-femoral crossover bypass surgery represents an alternative option to conversion to open surgical repair.

Endovascular Repair of Type IIIb Endoleak With the Amplatzer Septal Occluder

PURPOSE

To report the successful treatment of a type IIIb endoleak with an Amplatzer Septal Occluder.

CASE REPORT

A 76-year-old man was found to have a type IIIb endoleak in the proximal body component of a fenestrated graft at 4-year surveillance imaging; the leak was associated with rapid aneurysm growth. The anatomy of the graft and position of the fabric defect precluded treatment by relining with a secondary endograft. The defect was demonstrated with catheter angiography, sized with an angioplasty balloon, and repaired using an Amplatzer Septal Occluder. Follow-up imaging at 6 months showed no endoleak and marked reduction in the aneurysm size.

CONCLUSION

The Amplatzer Septal Occluder may be considered as an option for managing type IIIb endoleaks.

Intervention after endovascular aneurysm repair: Endosalvage techniques including perigraft arterial sac embolization and endograft relining

Endovascular aneurysm repair (EVAR) has revolutionized the treatment of abdominal aortic aneurysm (AAA). However, persistent AAA sac endoleak following EVAR can result in sac diameter increase requiring re-intervention in up to one-third of cases and even result in aneurysm rupture. In this case review, we summarize and detail endovascular re-interventions for each type of endoleak. We also detail specific options including stent-graft relining for indeterminate, Type III, and Type IV endoleaks and perigraft arterial sac embolization to induce thrombosis and resolve acute Type I, II, or III endoleaks. Endograft relining involves placement of a new stent-graft-elevating the bifurcation and extending the repair from renal artery to hypogastric arteries; perigraft arterial sac embolization involves placement of a catheter into the excluded sac from common femoral artery access, characterization of the inflow and outflow of the endoleak, and inducing cessation of the blood flow into the sac by the administration of thrombogenic material. Endoleaks range from low-pressure endoleaks, which can be safely monitored in a surveillance program to high-pressure endoleaks, which mandate intervention when associated with AAA sac diameter increase to protect from rupture. The evaluation of new devices and techniques to treat endoleak after EVAR remains an important issue in patient care after EVAR.

Type IIIb Endoleak and Relining

Purpose: To examine the changes in distraction force following relining of a conventional abdominal aortic stent-graft with a type IIIb endoleak using the Nellix endovascular sealing device compared to a unilateral stent-graft. Methods: Relining is often used to repair type IIIb endoleaks, but the consequences to graft stability are unknown. A mathematical model was constructed based on pressure and volume flow through the stent-grafts, incorporating recognized distraction force equations. Steady flow was presumed at peak systolic pressures to calculate the maximum distraction force, with gravity ignored. Distraction forces for 28- to 36-mm-diameter stent-graft bodies with 16-mm limbs were calculated and compared to forces following relining with single and double Nellix devices or the Renu unilateral device. Results: Distraction forces for the 28-, 32-, and 36-mm stent-grafts prior to relining were 5.99, 10.21, and 14.99 N, respectively. Similar forces were reported after relining with bilateral Nellix devices (5.86, 10.08, and 14.86 N, respectively). However, use of a unilateral Nellix increased the distraction forces to 9.92, 14.14, and 18.92 N, respectively. These were comparable to the increase observed after relining with a Renu unilateral stent-graft (9.87, 14.09, and 18.86 N, respectively). The proportional increase in distraction force for a unilateral relining ranged from 26% to 66%, with the greatest increase noted in the smaller diameter main bodies. Conclusion: Relining a stent-graft with a type IIIb endoleak using bilateral Nellix devices does not increase the distraction force. However, a unilateral Nellix device or the Renu system could theoretically increase the distraction force by up to 66%, potentially risking migration and type Ia endoleak. In clinical practice, these results suggest that a relining with bilateral Nellix may have benefits over the Renu unilateral stent-graft.

Type IIIb Endoleak With the Endurant Stent-Graft

Purpose: To report 2 cases of type IIIb endoleak with the Endurant stent-graft and postulate the cause for the events. Case Report: A type IIIb endoleak was diagnosed at open conversion for a ruptured aneurysm 4 years after implantation of an Endurant stent-graft. In the other case, the endoleak was diagnosed at angiography 4 years after the Endurant stent-graft was implanted; the stent-graft was relined. In both cases the fabric hole was in the body of the stent-graft at the level of the top of the contralateral limb. Conclusion: The cause of the type IIIb endoleaks in these cases was fabric erosion likely due to interaction between the bare metal at the top of the contralateral limb and the fabric of the stent-graft body.

The diagnostic and treatment challenge of type IIIb endoleaks

Type IIIb endoleak is a rare complication of endovascular aortic repair caused by endoprosthesis deterioration, leading to aneurysm pressurization and potential rupture. Because of its rarity, few cases are published. We report six cases of type IIIb endoleak in a 15-year period. Appropriate preoperative diagnosis was achieved in five cases; duplex ultrasonography, computed tomography angiography, and contrast-enhanced ultrasonography were useful diagnostic tools in one case, and angiography led to the correct diagnosis in four cases. In the remaining case, only surgical exploration identified the type IIIb endoleak. Successful treatment was achieved by endovascular relining in five cases and by surgical conversion in one case.