274 E. Fishman and P.L. FariesFig. 22.1 (a) Introduction of delivery device (Schematic of Parodi JC stent—graft1991). (b) Deployment of device (Schematic of Parodi JC stent—graft 1991)
27522 Endovascular Treatment of Infrarenal Aortic Aneurysmsendovascular repair. As technology advances the percentage ofpatients who undergo open repair is likely to become increasinglysmaller.1 AnatomyUnderstanding aorto-iliac anatomy is important for the successfulperformance of EVAR.Most AAA are infrarenal. However, up to 15% of AAA may havea juxtarenal or suprarenal component. Currently available FDA-approved devices can be used to treat most infrarenal AAA; however,fenestrated grafts or hybrid procedures are required to treat suprare-nal AAA. In the USA fenestrated grafts are currently available onlyon a trial basis. Some of these devices are more readily availableoutside the USA.A second anatomic factor of importance relates to the landingzone and the adequacy of the neck. A “neck” refers to the distancefrom the origin of the most distal renal artery and the beginning of theaneurysm. Currently most devices can treat AAA with a neck of upto 3.2 cm in diameter and 15 mm in length. The talent device isapproved to treat shorter (10 mm) necks. The ideal neck is parallel,with no angulation or eccentric thrombus in the wall. 45–60° angula-tion is the maximum suggested by the device manufacturers(Fig. 22.2). In cases where the diameter is not uniform throughout the(conical) neck, up to a 3 mm difference in diameter is well tolerated.The presence of an accessory or duplicated renal artery may reducethe neck length. In these cases the possibility of covering an acces-sory renal artery and the possibility of partial renal ischemia has to becarefully considered. Other factors, which are important in terms ofthe adequacy of the neck, are tortuosity of the aorta and the presenceand nature of thrombosis at the proximal seal zone. All devices todayare bifurcated and distally the stent is landed on the iliac arteries.Distally adequate seal zones require adequate arterial length anddiameter to prevent a distal type I endoleak. 20–30% of infrarenalAAA have common iliac artery aneurysms. If the common iliac arter-ies are short or aneurysmal, the devices may require external iliacartery deployment. In these cases the internal iliac artery or arteriesmay need to be embolized to prevent a type II endoleak; an internaliliac branched graft may be used in limited cases. Adequacy of
Fig. 22.2 (a) Treatment of AAA with talent device. Marked tortuosity of proxi-mal aortic neck presented signiﬁcant challenge to endovascular treatment. (b)Treatment of AAA with Talent device. CTA 3D reconstruction. (c) Treatment ofAAA with Talent device. Use of proximal extension prosthesis permitted deviceto conform to aortic neck and prevent endoleak at proximal ﬁxation site
27722 Endovascular Treatment of Infrarenal Aortic Aneurysmscollateral blood supply related to previous surgical history to thecolon and pelvic organs has to be taken into account. A large patentIMA may be cause for a type II endoleak and in some centers thisvessel may be embolized preoperatively.The third anatomic factor of importance relates to the access ves-sels. Standard deployment of stent grafts requires placement of largediameter sheaths in the common femoral arteries. Vessels of at least6 mm are required for the current available devices. In addition, tor-tuousity of femoral and iliac vessels may impede passage of thedevice. Although the use of stiff wire may allow some straighteningof these vessels, care must be taken to prevent risk of arterial rupture.Severe calciﬁcation (circumferential) of the vessels may also impedeadvancement of the device. Techniques such the use of an iliac con-duit, may allow for passage of the device. If one iliac vessel is simplynot amenable, an aorto-uni device and fem–fem bypass may beconsidered.Fig. 22.2 (continued)
278 E. Fishman and P.L. Faries2 Disease DeﬁnitionAn aneurysm is deﬁned as a 50% enlargement of a vessel. The nor-mal infrarenal aorta measures 2 cm on average in men and 1.8 cm inwomen. The normal common iliac artery measures approx 1.2 cm inmen. Most AAA are fusiform as opposed to saccular which areslightly more frequent in thoracic aortic aneurysms (TAA).In regards to etiology, more than 90% of aneurysm is degenera-tive. Although the term “atherosclerotic” is still commonly applied tosuch aneurysms, atherosclerosis per se is not a direct cause. Complexprocesses are associated with the pathophysiology of these aneu-rysms. Other causes of AAA are inﬂammatory or mycotic in nature.Inﬂammatory aneurysms that are not infectious in etiology are poten-tially amenable to EVAR. Mycotic aneurysms are not treated withEVAR since the focus of infection is still present. The exception is anemergency. EVAR can be used as a temporary bridge to deﬁnitiverepair for ruptured mycotic aneurysms. AAA is repaired to preventrupture which carries a high mortality rate. Size is the major factorassociated with aneurysm rupture. The relationship of AAA diameterand rupture risks is described subsequently. In addition to size, theaneurysm’s rate of increase over time, the patient’s cigarette usage,and life expectancy play a role in the decision to operate as opposedto the decision to observe. Clinical trials have been conducted com-paring observation versus repair.3 Disease DistributionThere are 27 million AAA patients worldwide. The prevalence ofAAA in the over 50 population ranges from 3% to 10% in multiplescreening and autopsy studies performed in the USA and internation-ally. In a VA-screening study of 73,000 patients the prevalence ofAAA is 4.6% among patients from ages 50 to 79. The rupture of anAAA is the 15th leading cause of death in the USA and the 10th lead-ing cause of death in men older than 55. These numbers have steadilyincreased since prevalence studies were performed starting 50 yearsago. The most signiﬁcant risk factors for AAA are smoking, age,gender, family history, and race. Men have a two to six times higherfrequency of AAA than women. Caucasians have a two to higher
27922 Endovascular Treatment of Infrarenal Aortic Aneurysmstimes frequency of AAA than non-Caucasians. Other less importantrisk factors are hypertension and hypercholesterolemia.The overall mortality of patients with ruptured AAA is 80–90%.30–50% of patients with ruptured AAA die prior to reaching thehospital. 30–40% of patients die after reaching the hospital withoutany intervention. There are approximately 40,000 elective AAArepair in the USA every year.Operative mortality rates for ruptured AAA range from 40% to50% though there is increasing evidence that mortality with endovas-cular repair will be lower.4 DiagnosisPhysical examination is very limited as a form of diagnosis in thiscondition. The positive predictive value of physical examination isonly 15%. Most AAA are found either incidentally during the courseof radiologic examinations for other reasons or, more recently, fromscreening programs. Multiple studies of ultrasound (U/S) screeninghave shown beneﬁt. Historically, most of these studies come from theUK. Today in the USA, Medicare reimburses, a one time screeningfor males 65 years and older. Screenings with a second ultrasoundhave not proved to add beneﬁt. Routine screenings for women are notgenerally recommended in the USA though screenings of womenwith speciﬁc risk factors, such as a positive family history or a historyof tobacco use are beneﬁcial. The most common conﬁrmatory test forphysical exam results is B-mode U/S. B-mode U/S is non-nvasive,inexpensive and therefore commonly used for follow-up of smallAAA. When the AAA reaches a size where repair is considered, athin cut (3 mm) CT angiogram (CTA) is the test of choice. If a repairis indicated, the CTA is useful in deciding upon whether the repairshould be open or endovascular. MRA is slightly more expensivethan CTA and requires more time for imaging, but it may be used inlieu of CTA in speciﬁc circumstance such as when platinum coilsfrom a previous embolization limits the beneﬁt of CTA, or if thepatient has an iodine dye allergy. Angiography is usually performedwhen a speciﬁc preoperative intervention may be required, such aspre-EVAR embolization of a hypogastric artery or the deﬁnition ofrenal vascular anatomy in cases where the patient has more than onerenal artery. Digital subtraction angiography is rarely required at
280 E. Fishman and P.L. Fariespresent for diagnostic purposes and frequently underestimates theaneurysm diameter.Alternative approaches such as CT without contrast, CO2as con-trast or intravascular US (IVUS) may be utilized for preoperativeplanning in patients with renal insufﬁciency. However the EVARprocedure itself requires contrast, therefore the renal function itselfmust be taken into account as comorbidity when evaluating a patientfor surgery.5 ManagementRepair of an asymptomatic AAA is prophylactic and elective. Thedecision for repair must weigh the risk of AAA rupture on the onehand with the operative risk and the patient’s life expectancy on theother. A thorough discussion of each of these factors with the patientis necessary for the patient to give informed consent.Although not ideal, the primary determinant of AAA rupture usedin practice is aneurysm size. In the UK small aneurysm trial (UKSAT)annual rupture risk was found to be 0.3% (3.9 cm or smaller), 1.5%(4–4.9 cm), and 6.5% (5–5.9 cm). These ﬁnding apply mostly to menwho encompassed 85% of the study population. Other studies withsimilar numbers document rupture rates of 10–20% (6–7 cm) and20–40% (>7 cm). (Table 22.1) Advances in predicting the risk ofrupture include models of aneurysm wall stress and ﬁnite elementanalysis.Table 22.1 Range ofpotential rupture rates fora given size of abdominalaortic aneurysmAAA Diameter (cm) Rupture risk (%/year)<4 04–5 0.5–55–6 3–156–7 10–207–8 20–40>8 30–50Brewster DC, Cronenwett JL, Hallett JW Jr,et al. (2003) Guidelines for the treatment ofabdominal aortic aneurysms. Report of the sub-committee of the Joint Council of the AmericanAssociation for Vascular Surgery and Society forVascular Surgery. J Vasc Surg.37:1106–1117
28122 Endovascular Treatment of Infrarenal Aortic AneurysmsLess signiﬁcant factors inﬂuencing the risk of rupture include femalegender and family history, smoking (active as well as past history)and the rate of the aneurysm’s expansion. Predicted rate of expan-sion is 10% of size per year. An expansion rate beyond 10% mayassist in the recommendation for repair in smaller aneurysm.Two major studies, The UK small aneurysm trial (UKSAT) and theaneurysm detection and management study (ADAM), have demon-strated a negligible risk of rupture in AAA less than 4 cm. Theseaneurysms may be followed with U/S. There was a clear beneﬁt ofAAA repair in aneurysms larger than 5.5 cm. Recommendation forfollow up versus operative intervention in aneurysms 4–5.5 cm mayvary according referral patterns, gender, and rate of expansionIn regards to endovascular repair, recently, two trials the CAESAR inEurope and the PIVOTAL study in the USA are in the process ofstudying the risk of rupture versus endovascular repair in aneurysmssmaller than 5.5 cm. Operative mortality of endovascular repair islower than for open repair and overall EVAR outcomes (in retro-spective reviews) have been shown to be better in smaller AAA.In terms of operative risk, open repair has had a steady 4% mortalityrate over the last few decades. EVAR has shown an operative mor-tality rate of approximately 1% in multiple studies. For this rea-son, the decision to intervene will be different if the patient is nota candidate for endovascular repair. Given the low mortality ratefor EVAR, prediction algorithms, which take into account thepatient’s comorbidities, have not been found to contributesigniﬁcantly to the calculation of operative risk.Calculating the life expectancy for candidates of AAA repair is notsimple. Factors such as the impact of the procedure itself, the patient’scomorbidities (both associated and independent from AAA), and ageof the patient are all contributing factors. (Table 22.2)Table 22.2 Life expectancy in years for patients surviving abdominal aorticAneurysm repair by age, gender, and raceAge (yr) TotalMale FemaleWhite Black White Black60 13 12 11 14 1365 11 11 10 12 1170 10 9 8 10 1075 8 8 7 9 880 6 6 6 7 6³85 5 4 4 5 5Rutherford’s Vascular Surgery 7th Edition Page 1941
282 E. Fishman and P.L. Faries6 Types of Stent GraftsAlthough there a many differences across stent-grafts, there are norandomized studies comparing one device to another. The EuroSTARdatabase provides information in the use and long-term follow-up ofa variety of devices. Use of one device versus the other may be morerelated to the physician’s comfort with a speciﬁc device than to thetechnical differences among devices. However, understanding thedifferences among devices in terms of construction speciﬁcations,beneﬁts and failure modes is of importance. The EVAR market wascalculated at 370 million US$ in 2004 and is projected to be 1.7 bil-lion US$ in 2012.At present there are six FDA-approved stent graft devices in theUSA. Among the Medtronic devices (Santa Rosa, CA), the Talentdevice has signiﬁcantly replaced the use of the AneuRx device, whichis no longer manufactured. Other devices in use are the Gore Excluder(W. L. Gore and Associates, Flagstaff, AZ), the Zenith (Cook, Inc.Bloomington, IN), and the Powerlink (Endologix, Irvine, CA).6.1 The Talent Device (Fig. 22.3)The endovascular stent graft developed by World Medical andMedtronic has been implanted in more than 15,000 patients world-wide. The Talent graft is used in two conﬁgurations: tapered/aor-touni-iliac and bifurcated/aortobi-iliac. It is self-expanding andcomposed of a Dacron graft with a nitinol frame, which supports thegraft. The proximal aortic ﬁxation device possesses a 1.5 cm ofuncovered nitinol frame proximal to the fabric portion of the device.This uncovered portion permits transrenal ﬁxation of the device,thereby allowing the treatment of AAAs with relatively short orangulated proximal necks. The Talent device may be used for proxi-mal aortic neck sizes up to 32 mm and for iliac implantation sitediameters up to 22 mm. Deployment of the device is similar to thatof the AneuRx device, although runners are not required for deliveryof the Talent device. The main aortic component with the ipsilateraliliac limb is delivered through a 22 or 24-French system. The second,contralateral iliac limb module is then deployed via the contralateralfemoral artery using an 18 or 20-French delivery system.
28322 Endovascular Treatment of Infrarenal Aortic Aneurysms6.2 The ExcluderThe Excluder is a modular endoprosthesis composed of PTFE bondedto a nitinol exoskeleton. There are proximal covered ﬂares, positiveﬁxation anchors, and a sealing cuff. Radiopaque markers are posi-tioned at the very end of the graft material. The device comes inaortic diameters of 23–31 mm and iliac diameters of 10–20 mm. Theipsilateral limb sheath is 18–20 Fr and the contralateral limb sheathis 12–18 Fr. The contraleral gate has a gold rim for opaciﬁcation. Thedevice is deployed with one rapid pull of the deploying cord.Connecting BarConnecting BarConnecting BarAORTICEXTENSION CUFFCONTRALATERALLIMBBIFURCATEDSTENT GRAFTILIACEXTENSION CUFFMini-support SpringMini-support Spring= Figur8 Radiopaque MarkerFig. 22.3 Diagram of Medtronic Abdominal Endograft Components
284 E. Fishman and P.L. Faries6.3 The ZenithThe Zenith system from Cook is a modular bifurcated device but isalso available in an aortouni-iliac conﬁguration. It consists of wovenpolyester graft material supported throughout its length by self-expanding stainless steel Z-stents. The introducer tip is tapered tominimize trauma at the arterial insertion site and there are side holesat the tip to allow angiography with the system in place. The Zenithstent-graft system has a bare proximal stent that expands radiallyupon deployment. There are barbs on this bare stent to secure thedevice to the suprarenal aortic wall. The suprarenal bare stent isdeployed after being released by a trigger wire, which holds it inplace to avoid premature deployment. The main aortic body isdeployed using an 18, 20 or 22-Fr. Sheath (inner diameter). The iliaclimb is delivered using a 14 or 16-Fr. sheath (inner diameter). TheZenith device can be used in aortic necks up to 32 mm and in iliacarteries up to 20 mm. The system is designed to allow all componentsto be used together and as a result a greater range of anatomic sizescan be managed with the Zenith graft.6.4 Endologix PowerLink SystemThe Endologix PowerLink system is a one-piece bifurcated graftcomprised of polytetraﬂuoroethylene (PTFE) supported by nitinol.The one-piece design eliminates the risk of endoleaks seen at attach-ment sites in modular devices. In addition, the frame is composed ofa self-expanding non-nitinol wire, which eliminates the need forsutures to hold individual stents in place. The graft is thin-walledPTFE, which may allow for downsizing of the delivery system. ThePTFE fabric is sewn to the stents only at the proximal and distal endsof the device. This allows the fabric to move off the endoskeleton.Aortic necks up to 26 mm may be treated.6.5 Other DevicesThere is a small group of stent grafts, which are currently used inEurope and not available in the USA In addition to these, there isconstant development of newer devices with modiﬁcations that may
28522 Endovascular Treatment of Infrarenal Aortic Aneurysmsallow use in patients who cannot undergo EVAR with the use ofcurrent devices. These include prefabricated or in-vivo fenestrations,branched grafts and larger aortic sizes.6.5.1 The Anaconda System (Vascutek, Terumo,Inchinnan, Scotland)The Anaconda stent-graft system for aneurysm treatment is a fullymodular system made of woven material one-third thinner than con-ventional graft material. The stents are made of nitinol. A uniquefeature is the proximal ring stent, which is composed of multipleturns of nitinol wire. The hoop strength that results from the radialforce of this ring stent allows the proximal end to anchor to the aorticwall. Because of the saddle conﬁguration of the proximal ring stent,the device can be placed so that the graft is situated at and above therenal ostia while the renal ostia themselves are uncovered. A systemof magnets is used to aid in cannulating the main body of the graft inorder to position the contralateral limb in place.6.5.2 Trivascular Enovus and Ovation (TrivascularCorporation, Santa Rosa, CA, USA)The Trivascular graft employs a novel technology to provide supportto the vascular graft material. Rather than employing metallic stentsalong the length of the graft material, the device contains longitudinalchannels that spiral along the course of the graft. After the device hasbeen positioned within the vascular system, the channels are ﬁlledwith a synthetic polymer that, when it subsequently hardens, providesradial and longitudinal support to the graft material. In eliminatingstent support along the length of the graft, the proﬁle of the devicehas been lowered considerably. As a result, the device may bedeployed through a 14-French system. This reduction in the diameterof the delivery system may ultimately allow for percutaneous appli-cation of this endovascular technology.6.5.3 Incraft (Cordis)The Incraft device has recently started a phase II trial. The devicesuses an integrated sheath of braided construction which allows for a
286 E. Fishman and P.L. Fariessmall proﬁle of 13 french. This ultra-low proﬁle may allow for use ina wider group of patients. The INNOVATION TRIAL is in progressin Germany and Italy at this time.6.5.4 Endurant (Medtronic)The Endurant device is used in Europe at present time. The device isundergoing evaluation in the USA for FDA approval. The device hasincreased ﬂexibility and smaller proﬁle with 18–20 French for themain device and 14–16 French for the contralateral iliac limb. Thedelivery system is hydrophilic with an inner nitinol in delivery devicefor support. Proximally, the device has suprarenal bare stent and cov-ered M-shaped stent for increased radial force and improved proxi-mal ﬁxation. There is availability of straight, tapered, or ﬂared limbsfor variable iliac anatomy.6.5.5 Aorﬁx (Lombard UK)The Aorﬁx device is designed for complex proximal aortic neck withan angulation of up to 90°. The ﬁshmouth design contributes to effec-tive sealing. This device has been used in small group of patients inEurope, Russia, and Brazil.6.5.6 Aptus (Aptus Endosystems INC.)The Aptus device uses helical endostapling technology for indepen-dent endograft ﬁxation. This device is being used on a trial basis inEurope, where it is used in primary or secondary intervention forcomplex necks.6.5.7 Nellix (Nellix Endovascular)The Nellix device uses a fully contained, polymer ﬁlled (PEG based)endobag, which conforms to aneurismal sac and theoretically reduces
28722 Endovascular Treatment of Infrarenal Aortic Aneurysmslikelihood of endoleak. This device is being used investigationally inNew Zealand and California.7 Stent Graft DesignStent grafts must create a seal for successful treatment of AAA totake place. One of the factors, which may prevent this seal, initiallyor in the long term, is migration of the graft distally. Other distalcomponents may also become separated from the normal aortic wallby forces created by the pulses pressure of blood ﬂow. There are dif-ferent methods of ﬁxation to prevent migration.Positive ﬁxation refers to the use of anchoring devices such asbarbs or hooks which embed into the aortic wall, which may providehigh ﬁxation force and prevent migration. Of note, some circum-stances such as proximal neck calciﬁcation may prevent embeddingof barbs. The, proximal covered ﬂares and sealing cuffs may providefurther apposition. Stent stiffness along the length of the graft mayuse a good seal in the iliac arteries to prevent migration of the proxi-mal end of the device. Radial force may keep the device in place.Suprarenal ﬁxation in which a bare stent extends proximal to therenal arteries may provide a theoretical advantage to prevent migration.Radio-opaque markers are present in different forms in all devices.It’s important to be aware of the different relationship of these mark-ers to the actual end of the stent-graft (which is not radio-opaque). Inthis manner deployment, proximally and opening of the contra-lateralgate will be performed in the exact location and angle desired.Since the initial development of stent grafts, there has beensigniﬁcant improved in ease of the deployment mechanism. Althougha device may be more “simple” to deploy, the only real important fac-tor in successful deployment is the understanding of device function.Each device has a different type, use, and proﬁle of sheath. Eachsheath has a different type of valve and may or may not allow for injec-tion of contrast through the device at time of deployment. Improvedﬂexibility and trackability of devices has reduced injury to the accessarteries. In the future an even lower device proﬁle may allow for per-cutaneous access to the femoral vessels. It’s important to keep in mindthat as devices evolve in minor characteristics, we must renew ourlong-term follow-up to conﬁrm the improvement of EVAR results.
288 E. Fishman and P.L. Faries8 Intervention: Technique and PitfallsWe perform all procedures in the operating room, where the utmoststerility and nursing as well as instrument access is present in case ofthe need for conversion to open repair. Anesthetic technique is mostlybased on the surgeon’s preference. The primary choice is betweenspinal anesthesia with mild sedation or general anesthesia. Exceptionsare severe pulmonary disease where spinal anesthesia may be a betteroption and situations when the need for iliac conduit makes generalanesthesia the better choice. We have used local with sedation, atleast initially, in cases of aneurysm rupture.Historically access to the femoral vessels has been performed inan open manner. With rare exceptions we perform a transverse inci-sion above the femoral crease. This may prevent slightly the rate ofwound complications. More recently the availability of closuredevices, such as the Proglide device with the preclose technique, hasallowed us to perform a percutaneous access in certain group ofpatients. CTA characteristics of femoral vessels (occlusive disease;calciﬁcation), U/S and micropuncture-guided access and body massindex (BMI) of patients are important factors to consider when utiliz-ing percutaneous access.If CTA evaluation of the external or common iliac arteries showssevere tortuousity, circumferential calciﬁcation, or severe occlusivedisease, a few maneuvers may be considered. If the anatomy is con-sidered prohibitive in terms of femoral access, an iliac artery conduitusing a retroperitoneal incision may be used. The anastomosis is per-formed in an end-to-side fashion with a 10-mm graft. After placementand deployment of the stent graft, the conduit stump may be over-sewed or may be anastomosed to the common femoral artery in anend-to-side fashion. This maneuver may allow for increased ﬂow incases of severe occlusive iliac disease or more importantly for the pos-sibility of need for re-intervention in the future. In our institution, inspeciﬁc groups of patients, we may perform an internal endoconduit.This procedure requires deployment of a covered stent (to preventiliac artery rupture) with subsequent angioplasty to allow for asufﬁcient diameter. Sewing an 8-mm PTFE graft to the distal end ofthe covered stent may allow for anastomosis to the common femoralartery at the end of the procedure. After access is acquired, stiff wireswill be required for delivery of the device. This type of wire willstraighten a tortuous iliac artery and allow for easier delivery of the
28922 Endovascular Treatment of Infrarenal Aortic Aneurysmsdevice. Stiff wires must be inserted with the use of catheters to preventarterial injury or plaque disruption. Initially a stiff wire is placedthrough the side of the main limb to the level of the descending tho-racic aorta. A pigtail is placed right above the renal arteries (L1–L2).Prior to starting to deploy, is important to plan the orientation ofthe contralateral gate, for ease of access of the gate. For proximaldeployment, a magniﬁed view is used. Parallax is avoided by center-ing the gantry over the renal arteries. Cranio-caudad angulation of thegantry is important to compensate for the possible anterior angulationof the aortic neck. In the same fashion visualizing the take-off of thelowest renal artery at right angle will allow for exact deployment(within 2 mm of lowest renal artery). This will limit the risk of typeI endoleak in short necks and minimize the risk for device migrationin the long-term.In terms of deployment, the Cook Zenith and Medtronic Talentdevices use a slow deployment. For these devices we begin withdeployment 1–2 cm proximal to intended deployment site. For theGore excluder, rapid deployment, the device is placed at the exact siteof intended placement. For the Gore or Medtronic device the maindevice is deployed until the ipsilateral limb is open. In speciﬁc casesthe ipsilateral limb may remain constrained to allow ease of contral-ateral gate access. For the Cook device the ipsilateral limb remainsconstrained. At this point the contralateral gate maybe accessed ordeployment of the suprarenal ﬁxation may be done ﬁrst.For access of the contra-lateral gate, putting the main device upthe more tortuous iliac (if safe from the proﬁle standpoint), mayallow for a straight shot at time of cannulation. For the Medtronic andGore device the limbs may be crossed or parallel depending on theangles of the iliac in question. For the Cook device crossing the limbsis not recommended.Access of the contra-lateral gate is successful in 99% of cases. Incase of inability to access the gate, conversion to an aorto-uni devicewith a femoral–femoral bypass is performed. To access the contra-lateral gate, an angle glidewire and catheters of different angles maybe used. If unsuccessful the wire may be snared from the main limb(up and over), or using brachial access. Deployment of the iliac limbsmust be performed with maximum coverage (as close to hypogastricas possible) to prevent migration and a distal type I endoleak in thefuture. After complete deployment of the device, a compliant balloonis used to complete apposition of the graft to the aortic wall. Care
290 E. Fishman and P.L. Fariesmust be taken to avoid inﬂating the balloon in the uncovered distaliliac arteries in order to prevent arterial injury or rupture. Completionarteriography is performed with an overall image and magniﬁedproximal and distal views. Endoleaks must be ruled-out, patency ofrenals and hypogastric must be evaluated and exact landing of thedevice proximally and distally must be conﬁrmed.For treatment of a proximal type I endoleak, after using the bal-loon for a second time, a proximal cuff and, if necessary, a large(uncovered) Palmaz stent may be used (Chap. 17—Endovasculartreatment of symptomatic abdominal aortic aneurysms). This some-times requires extending the coverage proximally at or above therenal arteries. To preserve the renal arteries the chimney graft tech-nique has been suggested.8.1 Chimney StentThis is a stent placed parallel to the aortic stent graft to maintain ﬂowto the visceral side branches including the renal arteriesm which wereoverstented to ensure an adequate seal. Depending upon the extent towhich the stent graft is deployed, this might require stenting of thesuperior mesenteric artery (SMA), one or both renals.Typically covered stents are used; however, uncovered stents canalso be used in certain circumstances. Both can be either balloonexpandable or self expanding, depending upon the need, whether theneed is for radial strength or ﬂexibility respectively.In preplanned procedures, a juxta-aneurysmal branch is cannu-lated in an antegrade fashion by brachial artery access. A hydrophilicglidewire is used to cannulate the branch. This is exchanged for a stiffwire such as an Ampltaz Super Stiff (Boston Scientiﬁc, Natick, MA,USA). Over this a long sheath with a stent is introduced into the sidebranch. The aortic stent graft is then released, and the renal stet isdeployed in the side branch as a chimney stent.For a distal type I endoleak, limb extensions may be used. If thesize of an ectatic common iliac artery does not allow for a proper seal,intra-op embolization of the hypogastric artery with limb extensioninto the external iliac artery may be performed. Newer brancheddevices are being developed to preserve ﬂow into the internal iliac.They are not FDA approved yet. A femoral–femoral bypass, or
29122 Endovascular Treatment of Infrarenal Aortic Aneurysmsexternal-to-internal iliac bypass may be performed to preserve ﬂowto the pelvis; although there is good evidence that preoperative, earlyembolization of one or both hypogastric arteries is well tolerated.9 Complications and Management(a) Endoleaks:ThesearedescribedindetailinChap.23—Endoleaks—Types and Management (Figs. 22.4 and 22.5).(b) Renal Artery Occlusion: Renal artery occlusion is primarilycaused by a deployment issue.Awareness of parallax, renal arteryangle, distance of covered graft to opaciﬁed markers is of para-mount importance. If partial renal artery coverage is diagnosed attime of procedure, attempt at stenting through brachial arteryaccess should be considered.(c) Graft Limb Occlusion: With the recent modiﬁcations of usingshort evenly distributed stents within the limb grafts, and ade-quate preoperative measurement, limb occlusion is uncommon.However, close early postoperative clinical surveillance musttake this potential complication into account. In case of suspicionof this, the patient should undergo a rapid CT angiogram.(d) Stent-Graft Infection: Prevention requires keeping strict sterilesurgical technique. Reported stent graft infection is low at lessthan 0.5%. However, if this does develop, this requires explanta-tion of part or all of the graft.(e) Pelvic Ischemia: Occlusion of one or both internal iliac arteriesmay lead to pelvic ischemia. Buttock claudication is the mostcommon consequence; at approximately 30% of patients withbilateral hypogastric artery occlusion. 50% of these patients’symptoms will usually resolve within 6 months, other patients’symptoms may improve. Other potential consequences of internaliliac artery occlusion are erectile dysfunction, buttock necrosis,ischemic colitis, colon necrosis, and spinal ischemia. Previouscolonic surgery where the SMAdoes not provide collaterals to thecolon and diseased profunda femoris artery with decreased pelviccollaterals are some of the risk factors.At our institution we embo-lize one side, wait 2 weeks looking for signs of ischemia of pelvicischemia and then wait another 2 weeks prior to EVAR. In speciﬁccases we perform routine sigmoidoscopy the day after surgery.
292 E. Fishman and P.L. Faries(f) Complications of VascularAccess: Rupture of the iliac artery attime of the delivery of the device is potentially catastrophic andmaintaining wire access when starting the closure of the arterymay be life saving. Alternatively, in case of suspicion an angio-gram with the sheath tip just inside the arteriotomy site can bedone. We routinely mark pulses or Doppler signals prior to start-ing the procedure. A dissecting ﬂap of a diseased access artery orembolization may cause distal vessel occlusion.Fig. 22.4 As in the ﬁgure
29322 Endovascular Treatment of Infrarenal Aortic Aneurysms10 Follow-up ProtocolAt this time, there is wide institutional variability in terms of EVARfollow-up. Initial rigorous follow-up with contrast-enhanced CT wasrequired to conﬁrm ongoing procedural success. Many institutionsstill used the initial protocol of a 1-month, 6-months, 1-year, and thenyearly CTA. A CTA with a non-contrast phase, an early phase (type Iand III endoleaks), and late phase (type II endoleaks) with 3D recon-struction. Recent studies have shown that up to 25% of endoleaksmay not be adequately characterized by CTA. To distinguish theFig. 22.5 As in the ﬁgure
294 E. Fishman and P.L. Fariessource of the endoleak, a duplex U/S (with or without contrast) or atime resolved MRA (dynamic 3D) may be helpful. MRA will not beuseful in stents made with stainless steel.After initial 1-month and 12-month follow-up with CTA someinstitutions advocate follow-up with a duplex U/S. A CT without IVcontrast can also be used and is accurate in terms of aneurysm sizegrowth. U/S is being used in many institutions as part of the follow-up protocol in attempts to minimize the use of CT or MR. However,U/S is operator dependent and may not be as accurate in obesepatients. Further studies are required to clearly determine a standardmulti-institutional protocol.11 OutcomesEVAR has replaced Open AAA repair as the procedure of choice intreatment of infrarenal abdominal aortic aneurysm. This is based onthe fact that in both level I randomized trials (EVAR I and DREAM)and both major registries (EuroSTAR and Lifeline), as well as inindustry-supported studies the 30-day mortality was 1.5% in average,and the 30-day mortality for open repair is 4.5–5%. Questions ofwhether or not this beneﬁt will hold up over the long term are difﬁcultto answer at the present time. Although the overall mortality curvesmeet around the 2-year mark and aneurysm related death meet at the4-year mark. In addition, in some of the studies, there may have beenan implicit bias against EVAR since healthier patients were morelikely to undergo open repair while patients who were less healthyand were not candidates for open repair underwent EVAR.One of the questions that have arisen has been whether EVARrequires more re-interventions and more readmissions to the hospitaland whether this explains the potential loss of beneﬁt when comparedto open surgery. However in a recent study, readmission and opera-tions for complications of open surgery (such as bowel obstruction9.7% and abdominal wall hernias 14.2%) were taken into account.The study demonstrated that EVAR patients did well in terms of long-term re-interventions.
29522 Endovascular Treatment of Infrarenal Aortic AneurysmsReferences1. Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantationfor abdominal aortic aneurysms. Ann Vasc Surg. 1991;5:491–9.2. Lederle FA, Wilson SE, Johnson GR, et al. Immediate repair compared withsurveillance of small abdominal aortic aneurysms. N Engl J Med. 2002;346:1437–44.3. The UK Small Aneurysm Trial Participants. Mortality results for randomizedcontrolled trial of early elective surgery or ultrasonographic surveillance forsmall abdominal aortic aneurysms. Lancet. 1998;352:1649–55.4. EVAR trial participants. Endovascular aneurysm repair versus open repair inpatients with abdominal aortic aneurysm (EVAR trial 1): randomized con-trolled trial. Lancet. 2005;365:2179–86.5. Prinssen M, Verhoeven EL, Buth J, et al. Dutch Randomized EndovascularAneurysm Management (DREAM) Trial Group. A randomized trial compar-ing conventional and endovascular repair of abdominal aortic aneurysms.N Engl J Med. 2004;351(16):1607–18.6. Schermerhorn ML, O’Malley AJ, Jhaveri A, et al. Endovascular vs. openrepair of abdominal aortic aneurysms in the Medicare population. N Engl JMed. 2008;358:464–74.7. Cao P. CAESAR trial collaborators. Comparison of surveillance vs. aorticendografting for small aneurysm repair (CAESAR) trial:study design andprogress. Eur J Vasc Endovasc Surg. 2005;30:245–51.