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

Transcription

1 J ENDOVASC THER 2014;21: CASE REPORT Type IIIb Endoleak Is an Important Cause of Failure Following Endovascular Aneurysm Repair Steven M. Jones, MBChB 1 ; S. Rao Vallabhaneni, MD, FRCS 1 ; Richard G. McWilliams, FRCR 1 ; Jagjeeth Naik, MD, FRCS 1 ; Tom Nicholas, FRCS 2 ; and Robert K. Fisher, MD, FRCS 1 1 Liverpool Vascular and Endovascular Service, Royal Liverpool Hospital, Liverpool, UK. 2 South Mersey Arterial Centre, Countess of Chester Hospital, Chester, UK. Purpose: To present confirmed cases of type IIIb endoleak in second and third-generation stent-grafts used for endovascular aneurysm repair (EVAR). Case Reports: Four patients developed type IIIb endoleak caused by fabric tears between 4 and 13 years following their initial EVAR. Three patients presented with rupture and one with aneurysm expansion of unknown cause. In each case, the type IIIb endoleak was confirmed at open surgery after imaging proved non-diagnostic. Only one patient survived. Had the cause for the expansion or ruptures been found prior to open reintervention, relining of the stent-graft may have been possible. Conclusion: Type IIIb endoleak remains difficult to diagnose. Avoidance of the high mortality associated with open secondary intervention requires a high degree of suspicion and it should be considered in any post-evar aneurysm expansion without an obvious cause. J Endovasc Ther. 2014;21: Key words: endovascular aneurysm repair, failure, endoleak, aneurysm expansion, rupture, diagnosis Stent-grafts used to repair abdominal aortic aneurysms (AAA) are known to suffer from structural disintegration. Fabric tears leading to type IIIb endoleaks can cause pressurization of the aneurysm with consequences such as aneurysm expansion and late rupture. This modality of failure is difficult to diagnose accurately. CASE REPORTS We have encountered 4 type IIIb endoleaks at our institution since our EVAR program began in One was a 69-year-old man who underwent elective endovascular aneurysm repair (EVAR) of a 70-mm infrarenal AAA in 2000 using a Talent stent-graft (Medtronic Cardiovascular Inc., Santa Rosa, CA, USA). Fluctuations in aneurysm diameter were considered unremarkable during the initial 7 years (Figure, A). Within this period, a type II endoleak involving an accessory right renal artery and the inferior mesenteric artery was diagnosed and persisted for at least 1 year. In year 9, the aneurysm diameter had increased by 22 mm over the preceding 2 years. A distal type I endoleak due to a loss of seal in the right common iliac artery was diagnosed on arterial-phase computed tomography (CT) and was confirmed by digital subtraction angiography (DSA). The residual engagement at the proximal and contralateral seal zones S. Rao Vallabhaneni has received conference travel and unrestricted research grants from Cook Medical. Robert Fisher is a member of the Marketing Advisory Board for Medtronic Inc. The other authors declare no association with any individual, company, or organization having a vested interest in the subject matter/products mentioned in this article. Corresponding author: Steven Jones, Liverpool Vascular and Endovascular Service, Royal Liverpool Hospital, Prescot Street, Liverpool L78XP UK. sjones2@liv.ac.uk Q 2014 INTERNATIONAL SOCIETY OF ENDOVASCULAR SPECIALISTS doi: / mr.1 Available at

2 724 TYPE IIIB ENDOLEAK CAUSING EVAR FAILURE J ENDOVASC THER Jones et al. 2014;21: Figure (A) Timeline for case 1. (B) Intraoperative view of stent-graft (arrow indicates detachment of stent apex due to suture breakage). TP: Teflon pledget, FD: flow divider. was also considered suboptimal, and secondary intervention with an Endurant cuff (Medtronic Inc.) and limb extensions was performed to rectify all of these. Follow-up arterial-phase CT and ultrasound at 1 month showed no residual endoleak, but 9 months later the patient presented with a symptomatic AAA rupture. At open operation, the only endoleak demonstrable was from a discrete fabric tear within the main body. The tear was due to the apex of a stent rubbing against the fabric as a consequence of stent-graft distortion and suture breakage (Figure, B). The seal zones were found to be intact. In an attempt to reduce the invasiveness of the operation, explantation of the stent-graft was not undertaken, and the fabric tear was instead repaired using a Teflon pledget. The patient made a slow recovery before discharge. In another case, a 65-year-old man underwent elective repair of a 60-mm infrarenal AAA with a Talent stent-graft in His aneurysm shrank to 36 mm and remained unchanged until year 9. A stepwise expansion of 39 mm over the next 5 years eventually threatened the integrity of the proximal seal zone. During this time, only a type II endoleak involving the inferior mesenteric and lumbar arteries could be found on contrast-enhanced ultrasound at 13 years. During open exploration, a type IIIb endoleak was found from a fabric tear at the same position as in case 1 (the lateral aspect of the main body ipsilateral limb). The stent-graft was explanted, but the patient died postoperatively of respiratory complications. The other two patients were treated over the last 2 years for type IIIb endoleaks secondary to fabric tears in Zenith stent-grafts (Cook Inc., Bloomington, IN, USA). Both presented with contained rupture. One was a 78-year-old man 4 years post-evar performed in another facility and lost to followup. The other was an 82-year-old who was seen 5 years following initial EVAR for a 55- mm infrarenal AAA. The aneurysm had expanded to 110 mm; 3 months prior to acute presentation, he had undergone embolization of a type II endoleak thought to be the cause of the expansion. Both patients had contrastenhanced CT scans that were diagnostic for contained rupture but not for type IIIb endoleak. Both proceeded to open operation where the fabric tears were identified on the right lateral aspect of the main bodies. One was near a stent apex in the row below the sealing stent, the other at the level of the bifurcation. The stent-grafts were left in situ with either pledget or tissue glue repair of the defect. Both patients eventually died from respiratory complications during the postoperative period. DISCUSSION The long-term results of the UK-EVAR 1 trial identified erosion of the initial survival benefit, 1 and a recent meta-analysis of late outcomes following EVAR showed no survival benefit after 2 years compared with open repair due in part to a significantly higher rate of aneurysm rupture. 2 This small series highlights an important cause of late rupture. It also demonstrates the difficulty in correctly

3 J ENDOVASC THER TYPE IIIB ENDOLEAK CAUSING EVAR FAILURE ;21: Jones et al. TABLE Confirmed Type IIIb Endoleak in Talent and Zenith Stent-Grafts Device Time Since EVAR, y Event Imaging Intervention Outcome Cao 3 Talent.5 Rupture CT Conversion Pitton 4 Talent CT 6 MRI* AUI þ Ax-fem Died Major 5 Talent 2.5 Expansion Conversion Seriki 6 Talent Late CT* Iliac limb extension Bove 7 Talent,2 DSA* Relined Bucci 8 Talent 6 Symptomatic expansion CT* þ DSA AUI Survived Reijnen 9 Talent 4 CT þ DSA* Relined Survived Mertens 10 Zenith 2 Iatrogenic DSA* Survived Juszkat 11 Zenith 0.5 DSA* AUI Survived Wanhainen 12 Zenith 7 Rupture CT Relined Died EVAR: endovascular aneurysm repair, DSA: digital subtraction angiography, AUI: aortouni-iliac stent-graft with crossover bypass, Ax-fem: axillofemoral bypass, CT: computed tomography, MRI: magnetic resonance imaging. * Indicates diagnostic imaging for type IIIb endoleak. diagnosing this scenario in surveillance and undertaking a remedial action safely. Worldwide there have been ~45,000 Talent and.100,000 Zenith stent-grafts deployed. Despite this, reports of type IIIb endoleak remain sparse The apparent low incidence is partly due to the lack of devicespecific data and the convention of reporting type I and III endoleaks together. When these endoleaks were reported separately, there was often a lack of distinction between type IIIa (component separation) and type IIIb (fabric tear). The EVAR trials, for example, contained a total of 21 type III endoleaks, but even the in-depth analysis of 27 post-evar ruptures did not specify what kind of type III endoleak occurred. 13 The lack of complete and accurate data was highlighted by a recent systematic review of late ruptures following EVAR. 14 Graft material failure was the cause of rupture in 97 of 270 cases, but only 40 of these included a description of the type of stent-graft implanted. The term graft material failure was also used to describe component separation and migration due to stent fracture. All of the confirmed ruptures due to type IIIb endoleaks occurred in historic devices (AneuRx, Stentor, and Vanguard). Experience with these historic models has helped to clarify the mechanisms by which stent-graft failure may occur. 15 Suture breakage and excessive abrasion of the graft fabric may cause type IIIb endoleak in the absence of stent fracture. 16 This has been noted in explanted Talent stent-grafts as early as 16 months post deployment. 17 The impaired healing process that occurs around most endovascular devices leaves them poorly incorporated into the surrounding aorta and offers little added protection in the event of fabric failure. 5 To the best of our knowledge, there are only 10 confirmed examples of type IIIb endoleak in Talent and Zenith devices in the literature (Table). In contrast to our experience, seven of these cases were diagnosed by CT, DSA, or magnetic resonance imaging in one case. In our short series, the initial expansion in case 1 was thought to be due to the type Ib endoleak. Arterial-phase CT and duplex scans following secondary intervention revealed no other abnormality. Similarly arterial-phase CT was diagnostic for rupture but did not reveal the cause. DSA was not repeated at this stage. Case 2 was followed with radiography and contrast-enhanced ultrasound only due to previous severe contrast reaction. Despite a 5-year period of intermittent expansion, no target for treatment could be found. The trigger for reintervention was evolving compromise of the proximal seal zone, and the late type II endoleak was not considered a likely cause. Case 4 highlights how late type II endoleaks may represent the outflow for another intermittent graft-related endoleak. Embolization in this setting may lead to rapid AAA expansion and rupture. The type IIIb endoleak in this

4 726 TYPE IIIB ENDOLEAK CAUSING EVAR FAILURE J ENDOVASC THER Jones et al. 2014;21: last case eluded diagnosis despite dual-phase CT, standard ultrasound, and DSA. Had a prior diagnosis of type IIIb endoleak been made in any of our cases, relining of the stent-grafts may have been possible. This endovascular solution would have carried less risk and would also have addressed the possibility that one fabric hole may be indicative of pending global fabric failure. In the absence of confirmed type IIIb endoleak, empirical relining of the entire stent-graft would be necessary. This requires a high index of suspicion but may be justified given the apparent risk of rupture or death from open intervention associated with this mode of stent-graft failure. It is now our practice to perform triple-phase CT imaging, standard and contrast-enhanced ultrasound, and DSA if considered appropriate for all patients with an undiagnosed cause for expansion following EVAR. Each individual case is reviewed at a multidisciplinary meeting of vascular and endovascular specialists. An alternative to relining of a failing stentgraft is explantation and conversion to open repair. Up to 73% of explantations in a recent series were performed for types I, II, or III endoleak. 18 In the elective setting, explantation may be performed with as little as 0 to 3.3% mortality, but in the presence of rupture, the mortality can be considerably higher. 19 The long delay (4 13 years) and physiological deterioration since initial EVAR contributed to the decision to perform a pledget or tissue glue repair in three of our cases instead of explantation. We recognize that this type of repair represented only a temporary solution in a difficult situation, but it may have enabled relining to be performed at a later stage. Delayed relining was eventually contraindicated in the only surviving patient due to deteriorating respiratory function. Conclusion Type IIIb endoleak is difficult to diagnose and may be more common in second- and third-generation stent-grafts than confirmed reports suggest. Type II endoleak should not be accepted as the cause of expansion until multimodal investigations with temporal information regarding perigraft blood flow have been completed. Empirical relining of the entire stent-graft may be indicated to avoid the high mortality from rupture or open reintervention, but this approach requires a high degree of suspicion of type IIIb endoleak in any expanding aneurysm without an obvious cause. REFERENCES 1. Brown LC, Powell JT, Thompson SG, et al. The UK EndoVascular Aneurysm Repair (EVAR) trials: randomised trials of EVAR versus standard therapy. Health Technol Assess. 2012;16: Stather PW, Sidloff D, Dattani N, et al. Systematic review and meta-analysis of the early and late outcomes of open and endovascular repair of abdominal aortic aneurysm. Br J Surg. 2013; 100: Cao P, De Rango P, Parlani G, et al. Durability of abdominal aortic endograft with the Talent Unidoc stent graft in common practice: core lab reanalysis from the TAURIS multicenter study. J Vasc Surg. 2009;49: Pitton MB, Scheschkowski T, Ring M, et al. Tenyear follow-up of endovascular aneurysm treatment with Talent stent-grafts. Cardiovasc Intervent Radiol. 2009;32: Major A, Guidoin R, Soulez G, et al. Implant degradation and poor healing after endovascular repair of abdominal aortic aneurysms: an analysis of explanted stent-grafts. J Endovasc Ther. 2006;13: Seriki DM, Ashleigh RJ, Butterfield JS, et al. Midterm follow-up of a single-center experience of endovascular repair of abdominal aortic aneurysms with use of the Talent stentgraft. J Vasc Interv Radiol. 2006;17: Bove PG, Long GW, Shanley CJ, et al. Transrenal fixation of endovascular stent-grafts for infrarenal aortic aneurysm repair: mid-term results. J Vasc Surg. 2003;37: Bucci F, Fiengo L, Valerio N, et al. Late type IIIb endoleak after endovascular aneurysm repair: case report and review of the literature. G Chir. 2011;32: Reijnen MM, Minion DJ, Lardenoye JW. Treatment of a type IIIb endoleak in a Talent endograft using telescoping cuffs and two parallel upside-down excluder contralateral legs. J Vasc Surg. 2012;56: Mertens J, Houthoofd S, Daenens K, et al. Long-term results after endovascular abdominal aortic aneurysm repair using the Cook

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