Endovascular Common Iliac Aneurysm Exclusion with Antegrade Hypogastric Artery Flow Preservation: A...

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Successful Endovascular Exclusionof a Common Iliac Artery Aneurysm:Off-Label Use of a Reversed CookZenith Extension Limb Stent-Graft

Luis R. Leon Jr., MD, RVT, and Joseph L. Mills Sr., MD

Open iliac aneurysm repair has been historicallyassociated with major morbidity and mortality. Theintroduction of endovascular devices and techniqueshas expanded the armamentarium available to treatthese aneurysms, and several methods have beenreported. However, the off-label use of a commerciallyavailable, flared extension limb stent-graft to treat acommon iliac artery aneurysm (CIA) by preliminaryextracorporeal predeployment, endograft reversal, andreinsertion into the delivery sheath to fashion a

tapered endograft has not been previously reported.A case report of a CIA aneurysm diagnosed 9 yearsafter transperitoneal tube graft abdominal aorticaneurysm repair treated with ipsilateral hypogastricartery occlusion with an Amplatzer plug and place-ment of a reversed, tapered extension limb stent-graft is herein presented.

Keywords: aortic endografts; Amplatzer plug; iliacaneurysms

Introduction

Iliac artery aneurysms are challenging to manage andhave traditionally been associated with high opera-tive mortality rates,1 prompting the search for alter-native and less invasive techniques to lower mortalityand morbidity rates. A great deal of creativity isneeded to allow application of the currently availableendovascular devices to the anatomic configurationof the aneurysm, especially when an open approachis thought to be associated with a high risk ofcomplications. The durability and effectiveness ofendovascular iliac artery aneurysm repair, comparedwith direct surgical repair, have been questioned.The present case report broadens the spectrum of

endovascular approaches available to treat iliacartery aneurysms.

Case Report

A 74-year-old man with a history of an open abdom-inal aortic aneurysm (AAA) tube graft repair about9 years prior to his current presentation, developedan asymptomatic, true right common iliac artery(CIA) aneurysm, measuring 3.6 cm in maximal dia-meter (Figure 1). His past history was also significantfor hypertension, hyperlipidemia, tobacco depen-dency, and prostate cancer treated with hormoneinjections. He exercised on a daily basis and denieda history of cardiac problems or symptoms.

Given the size of this aneurysm and previousopen abdominal surgery, endovascular repair underlocal and monitored anesthesia care was proposed.This approach consisted of left common femoralartery percutaneous access and 6F (French) sheathplacement, with a selective up-and-over right hypo-gastric artery catheterization, followed by successful

From the Vascular Surgery Section, Southern Arizona VeteranAffairs Health Care System (LRL), and the Vascular Surgery Sec-tion, University of Arizona Health Science Center (JLM), Tucson,Arizona.

Address correspondence to: Luis R. Leon Jr., MD, RVT, VascularSurgery Section Room N259, 3601 South 6th Avenue, SouthernArizona Veteran Affairs Health Care System, Tucson, AZ 85723;e-mail: luis.leon@va.gov.

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deployment of a 14 mm Amplatzer plug (AGA MedicalCorp, Plymouth, MN) to eliminate retrograde bloodflow from the hypogastric artery into the CIA aneurysmsac. Endovascular exclusion of the right CIA aneurysmwas then performed by using an 18 � 54 mm2 TFLEflared iliac extension limb (Cook Medical, Blooming-ton, IN). Open surgical exposure of the right com-mon femoral artery was performed. A standardTFLE limb was brought into the operative field, andit was deployed on a separate Mayo table. Then, afterreversing the orientation of the stent-graft, it wasreloaded into the 16F delivery system, aided by thesequential application of crossed vessel loops andsurgical silk ties to permit gentle reintroduction ofthe now tapered endograft into the delivery system(Figures 2 to 5). The stent-graft was advancedthrough the right common femoral artery over anextra-stiff Lunderquist guidewire (Cook Medical,Bloomington, IN). Under fluoroscopic guidance, thestent-graft was precisely deployed, beginning at themost proximal aspect of the right CIA, spanningacross the aneurysm sac, and landing distally inthe proximal right external iliac artery (Figure 6).Postdeployment balloon dilatation of both proximaland distal implantation sites was performed with a32-mm CODA balloon (Cook Medical, Blooming-ton, IN). The patient did well postoperatively andwas discharged the day after intervention. Intra-operative completion angiography and postoperativecontrast-enhanced CT (computed tomography)scans (Figure 6) revealed successful completeendovascular exclusion of the aneurysm and absence

of retrograde flow from the right hypogastric artery.No evidence of endoleak or any other procedure-related complications were noted.

Discussion

Isolated iliac artery aneurysms are relatively rare. Theyusually accompany AAAs. When the iliac arteries areectatic (12-18 mm)2 or mild-to-moderately aneurys-mal and the AAA is large enough to require repair,the surgeon must decide whether to address the iliacarteries concomitantly or repair the AAA alone andperform surveillance imaging, depending primarilyon patient comorbidities and life-expectancy.Subsequent iliac aneurysmal dilatation over time isan obvious risk whenever iliac ectasia or small aneur-ysms are not treated at the time of the first interven-tion. Open surgical repair of iliac aneurysms hasbeen traditionally associated with major morbidityand mortality.1,3

More recently, endovascular techniques haveexpanded the options for treatment of these aneur-ysms, especially for patients for whom open interven-tion is a high-risk procedure. Endovascular optionsmay be limited by extension of the aneurysm to theiliac bifurcation, on occasion necessitating endograftextension into the external iliac artery, such as in thecase of the patient reported herein. If the latter isneeded, then antegrade flow to the hypogastric arterywill be interrupted. When unilateral, this is often

Figure 1. Three-dimensional reconstruction of a computed tomographic scan, showing frontal (left panel) and posterior views(right panel) of a 3.6 cm aneurysm in the right common iliac artery. Measurements indicated an adequate proximal neck but aninadequate common iliac landing zone distally, necessitating the placement of the distal portion of the stent-graft into the externaliliac artery, with the consequent need to occlude the flow to the ipsilateral hypogastric artery.

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well tolerated because of preservation of blood flowfrom the contralateral hypogastric artery.

At the present time, there are no devices spec-ifically approved for scenarios such as the one hereinpresented. The multitude of clinical and anatomicalscenarios has generated creativity among vascularand endovascular surgeons to modify existing endo-vascular devices and techniques to accommodatethese challenging cases. We report a novel approachto successfully treat a patient with a large commoniliac aneurysm that developed remotely after openAAA repair. Our approach necessitated off-label useof a commercially available, flared extension limbstent-graft. To the best of our knowledge, this spe-cific endograft modification has not been previouslyreported in the literature to treat an iliac aneurysm.

The therapy of the aneurysmal segment waschallenging. Figure 1 shows the aneurysm, situatedbetween a segment of proximal CIA, with a meandiameter of 16 mm and a neck length of 10-12mm. We felt that the proximal neck was adequateto achieve successful sealing. Distally, the neck was

of inadequate length, and therefore, we felt thatocclusion of the ipsilateral hypogastric artery wasnecessary to prevent the occurrence of retrogradeaneurysm sac flow from cross-filling pelvic colla-terals. We are aware of some reports claiming thatcoverage of the hypogastric artery without prelimi-nary coil embolization is possible,4 but we were con-cerned about the significant potential for continuedsac pressurization from a large type II endoleak. Sev-eral techniques could have been used for this pur-pose. We chose to use the Amplatzer vascular plug,a self-expanding cylindrical appliance consisting ofa nitinol-based wire mesh. Embolization with thisdevice has been noted to be safe, feasible, effective,and technically simple with appropriate patientselection in various vascular territories.5,6

The distal end of the stent-graft had to extendinto the mid–external iliac artery, ideally above thepoint of maximal tortuosity (Figure 1). The diameterof the external iliac artery was 10 mm in the pro-posed landing zone. Commercially available coveredstent-grafts are not generally tapered or of sufficient

Figure 2. Shown on the top left, are the 18 � 54 mm2 TFLE flared iliac extension Cook limb, silicone vessel loops, and silk surgicalties, materials suggested for resheathing. On the top right, the stent is shown being deployed on a separate Mayo table; bottom left,the stent has been fully deployed. At bottom right, the stent has been mounted in a reversed fashion into its original sheath to allowretrograde delivery of the wider end of the stent in the common iliac artery and the tapered end in a distal position into the proximalexternal iliac artery.

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Figure 3. The sequential steps to follow for resheathing are demonstrated. We suggest the use of silk ties for the initial segment,where there is fabric on the outside and metallic stents on the inside (top left). Once that segment has been introduced (top right),vessel loops are used to crimp the metallic stents on the outside (bottom left) while the stent is manually resheathed. A silk tie placedmore distally on the stent (bottom right) aids greatly in the insertion process.

Figure 4. From the top right, proceeding in a clockwise manner, the suggested sequence to allow reinsertion of the stent into itsoriginal sheath is demonstrated.

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diameter to accommodate our needs. Ideally, wesought a tapered 18 � 12 mm2 stent-graft, with alength of about 75 mm (proximal common iliac tomid–external iliac artery). The use of a Cook ZenithRenu (Cook Medical, Bloomington, IN) converterwas suggested but dismissed because of the lengthof the available devices, which because of mid–distalexternal iliac artery tortuosity was felt to be too longfor this particular case. Therefore, we chose the off-label use of a Cook Zenith flared extension limbstent-graft. These limbs are available in a large vari-ety of sizes and lengths. We selected a 77-mm long,18 � 54 mm2 stent-graft, which flares from 12 to18 mm. However, to accommodate the larger dia-meter in the proximal CIA and the smaller diameterlanding zone in the external iliac artery, the stent-graft had to be reversed and resheathed. The concepthas been successfully reported in the past but using adifferent graft and applied to a different arterial seg-ment.7 The extent of manipulation required to reac-commodate the stent-graft inside the delivery systemis worrisome. Meticulous technique is required toavoid fabric damage from tying down the silk suturesor to avoid strut fractures from such manipulation,both of which could potentially result in a type IVendoleak.

The short-term and midterm results of endolum-inal stent-grafts to treat iliac artery aneurysms arefavorable. A retrospective analysis of 34 iliac aneurysms

and pseudoaneurysms treated using covered stents8

reported an initial technical success rate of 97.6%.Patency of the ipsilateral hypogastric artery was pre-served in only 4 cases, however, and the remainingcases were treated with preoperative coil emboliza-tion or intraoperative stent hypogastric coverage.Parsons et al9 reported the midterm results of 28isolated iliac artery aneurysms treated withpolytetrafluoroethylene-covered stents. The 3-yearprimary patency rate of iliac endovascular stent-graftswas 86%. The procedural complication rate was12%, including distal embolization, wound compli-cations, and colon ischemia. Of interest was thatonly a minimal reduction in the aneurysmal diameterwas seen during follow-up in 90% of the iliac arteryaneurysms treated. The remaining sacs showed nochange in diameter, but no aneurysm increased incross-sectional diameter on CT images during afollow-up period of up to 4 years (mean, 24 months).One aneurysm ruptured after apparently successfulendovascular exclusion, and the patient underwenttreatment with open repair. Sanchez et al10 reportedsimilarly favorable results. More recently, Bouleset al11 examined 45 patients undergoing endovascu-lar repair of 61 isolated iliac artery aneurysms. Peri-operative major complications included 1 early graftthrombosis that eventually required conversion toopen repair and 1 groin hematoma that requiredoperative evacuation. Late complications duringfollow-up included 1 additional graft thrombosis and1 late death after amputation. No late rupturesoccurred during a mean follow-up of 22 months(range, 0-60 months). Primary patency at 2 years was95%, and freedom from secondary interventions was88%. Microscopic findings after stent implantationhave been reported by White et al12 after theyexplanted a covered stent (6 cm � 14 mm Dacronprosthesis with Palmaz 308 [Cordis, Miami Lakes,FL] stents sutured to either end of the graft) that wasplaced in an elderly, high-risk patient with a 4 cmCIA aneurysm. The patient died about 2 monthsafter implantation from a complication unrelated tothe procedure. At autopsy, complete aneurysm isola-tion was confirmed by the fully expanded endolum-inal prosthesis. The graft surface was covered by aglistening, thin, fibrinous membrane, and the graftmaterial was filled with hypocellular fibrinous mate-rial, with no evidence of endothelialization.

Flared distal cuffs contained within the commoniliac arteries (‘‘bell-bottom’’)13 have also been usedwith success. However, this technique has been

Figure 5. Three sequential photographs show the finalappearance after successful resheathing. The entire length ofthe stent has been reintroduced, and the gray introducer is inperfect apposition with the sheath without step-off. The sheathwith the resheathed stent is now ready to be deployed across thecommon iliac aneurysm.

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recommended only in cases of CIA ectasia (16-20mm),14 not for large aneurysms such as in our case.In spite of favorable early success, long-term evaluationis essential because the risk of rupture resulting frompotential expansion of the excluded iliac artery aneur-ysm or late device failure is unknown.

Iliac branched stent-grafting is a promising tech-nique currently under trial15-17 and would have cer-tainly been a good option for our case. However, atthis time, this approach was not considered becauseof the lack of device availability.

Conclusions

The introduction of endovascular approaches totreat aneurysmal disease of the iliac arteries greatlybroadens the therapeutic possibilities, which is espe-cially important in patients for whom open surgicalintervention is a high-risk procedure. Endovasculartreatment of iliac aneurysms that extend close to theiliac bifurcation often need stent end-point fixationin the external iliac artery to obtain adequate distalseal and successful iliac aneurysm exclusion. Wehave described a novel technique using back tablemanipulation of a commercially available stent-graft to accommodate a challenging anatomical

scenario. The short-term results of the endoluminalrepair of iliac aneurysms are favorable; however,long-term follow-up of these procedures is warrantedto assess the durability of the repair and absence ofcomplications.

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Figure 6. Postoperative 3-dimensional reconstruction of an early computed tomography scan showing the metallic struts of thestent-graft in the proximal common iliac (small arrow) and the Amplatzer plug in the hypogastric artery (large arrow). The picture onthe right depicts the reversed extension limb stent-graft deployed from the most proximal aspect of the right common iliac artery,spanning the aneurysm sac, with its distal end positioned in the proximal right external iliac artery. No evidence of endoleak isdemonstrated.

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