PURPOSE: To evaluate a new animal model of venousstenosis induced by surgical arteriovenous fistula cre­ation and local mechanical injury.

An Arteriovenous Stenosis Model in Swine.YH. Dong, The Cleveland Clinic Foundation,Cleveland, OR, USA· B. Dolmatch • LH. Brennecke

RESULTS: At angiography six AY anastomoses werepatent without stenosis, five were stenosed and one hadoccluded. Eleven of twelve venous injury sites with openAV anastomosis and six of ten venous injury sites withAV anastomotic stenoses developed greater than 50% di­ameter stenosis. Dilation was found in the non-injurysegment of eight jugular veins. Stenoses were caused byneointimal hyperplasia (histologic examination).

MATERlALS AND METHODS: Twelve arteriovenous fis­tulae (AYF's) were surgically formed between thecarotid artery and internal jugular vein in six pigs, oneon each side of the neck. Direct mechanical injUry wasmade by crush injUry with forceps to the jugular vein 1­2cm above and below the anastomosis. Angiographicfollow-up was performed at 3 and 6 weeks, and the an­imals were sacrificed. Fistulae and injured veins wereharvested for histopathology.

RESULTS: The 223 patienu had 59 procedlLre per­form d during 33 month·, of whi h 369 ere en- .aunt rs for diagnosi or Ir atmenl of fi rula dys­

fun rion. The procedures p rformed included 53declotring proc dure , 1 3 acce s angiograms with

. PT , and 133 diagno.lic exams without endo a cu­lar rherapy. Demographic and . m rbid conditionshow d no variation from our g n ral populationother than gender(6 Yo male, 31% t m I ) in vari­an era U RD figures of 520/0 male. 'uccess rates ford lorting pI' cedure how 7% recanalization fornati e fistulae and 88% for graf . in the sam pa­tient . PTA for dy. funcrional (and poorly maturing)fisnilae had a 97 0 llcce s rat . Complications weI'less than 2%. Patency afrer· declotting was %, 57%,and 3 Vo m3, . and L months respectively. Patencyfollowing PTA wa' 82%, 53% and 28% ill 3, 6, ancl12 months respectively. Immature fistulae wer on­verted to usefulne sand maturiry in 33/43 (77%) ofcases preseming as failure to matur .

CONCL 1 N Endova cular pro edure for recanal­ization of thrombosed native fj tube result In returnof function in aImo L 900A> of cases and leads to pro­longed usefulne of the ile. Immarur fistulae canbe convert d to IUncti nal a e es I y planned en­dova. utaI' intervention.

Abstract No. 1354:5] pm

CONCLUSION: Neointimal venous stenosis can be in­duced by creation of a surgical AY fistula and local ve­nous mechanical injury. This model may be used tostudy methods to reduce or inhibit neointimal hyperpla­sia, with particular reference to venous stenoses thatoccur in arteriovenous shunts created for dialysis access.

Native Arteriovenous Fistulae for Hemodialy!i'is

Acc ss: Three years Experience withEndovascular Maintenance.W Arnold, RAIS Lifeline-Baltimore, Timonium, MD,

U. A·M. Replogle

BACKGROl.hVDIPl/RPO E: Th i'\.K.F. Dialysis Out­com('s Quality Initiative (DOQI l' 'commen Is nativearter ovenou fi tula' as the preferred hel1lodialy ivascular acc . W, r vi wed patients with nativefisrula ref rred for evaluation and ituerventi novel'three years in a uedicated hemodialy is access inter­ventional pra lice to how -the utcom s of thismode of therapy on native fi tula a ce s patency.

MA1ERJAl AND ME1HODS: During the first 33months of operation, 223 patients with native fistulaewere s en f r evaluati n and treatment for aecesmanag ment. Data were entered into an outcomes.databa e and lh I' suIts of car were analyzed. Indi­cations for tr atment included thrombo i , poor'tlow, el vated pr i';UJ", and failure 10 mature.

Scientific Session 18Aortic Endografts for AneurysmsModerator: John A. Kaufman, MD

Goetz Riehte1; MD

Abstract No. 1373:45 pm

Tuesday, March 6, 20013:45 pm-5:15 pm

Endovascular Stent Graft Repair of AbdominalAortic Aneurysms in Female Patients: Technical

Challenges and Outcomes.c.s. Pena, Massachusetts General Hospital, Boston, MA,

USA • C.M. Fan· S.c. Geller· A. Greenfield·D.C. Brewster • A.C. Waltman, et al.

PURPOSE: To assess technical differences due to iliacaccess issues as well as clinical outcomes between fe­male and male patiems undergoing stem graft repair ofabdominal aortic aneurysms.

MATERJAlS AND METHODS: A retrospective review wasperformed of clinical records as well as pre and postprocedure CT angiograms of 333 patients undergoingstem graft repair of AAA at a single institution. 57 of 333patients (17%) were female and 276 of 333 patients(83%) were male. Preprocedure diameters of theaneulysm sac, common iliac artelY (CIA) and externaliliac artelY (ELA) were obtained. Complex access eventswere defined as actions which traumatized the vessel(transection, rupture, or dissection); facilitated stent graftplacement (predeploymenr PTA or chimney delivery); 855

Abstract No. 136

FEATURED ABSTRACTCommentator: Scott O. Trerotola, MD

5:02 pm

and necessitated vessel repair (surgical repair or stent­ing) , Postprocedural imaging evaluated treatment re­sponse by measuring changes in aneurysm sac diameter.

PURPOSE: To determine the complications of preopera­tive internal iliac artery (IIA) embolization using a com­bination of coils and gelatin sponge, before stent-graftrepair of abdominal aortic aneurysms (AAA) and iliacartery aneurysms.

Internal Iliac Artery Embolization Prior to Stent­Graft Repair of Aortoiliac Aneurysms:Complications Using Coils and Gelatin Sponge.S.P Millward, London Health Sciences Centre, London,

ON, Canada • G, De Rose • S, W Kribs • fA, Elliott.

TL. Forbes • K.A. Harris

CONCLUSION: Female patients undergoing AAA en­dovascular repair have smaller access vessels whencompared to male patients, This is associated with twicethe rate of complex iliac access events in female pa­tients. However, once treated female and male patientsdemonstrate similar response to treatment.

Abstract No. 140

Abstract No. 139

4:18 pm

4:07 pm

CONCLUSION These results of IIA embolization with acombination of coils and gelatin sponge are similar topublished results using coils only. Embolization of theITA bifurcation to complete occlusion does not increasethe risk of complications.

RESULTS: Preliminary results reveal the onset of mild tomoderate buttock claudication in both patients undergo­ing bilateral hypogastric artery embolization. In bothcases, claudication followed embolization of the secondhypogastric artery. Buttock claudication has remainedunchanged at 3-4 months follow-up. No buttock clau­dication occurred in unilateral embolization of the hy­pogastric artely. There was no evidence of bowel, blad­der, or sexual ischemic complications following unilateralor bilateral hypogastric artery embolization.

CONqUSION In our population of patients, buttockclaudication was found to be of clinical relevance fol­lOWing bilateral hypogastric artery embolization. Unilat­eral embolization allows for the persistence of collateralflow, minimizing the long-term ischemic risks.

MATERIALS AND METHODS: During a 2 year period, 85patients were treated with stent-grafts for known ab­dominal aortic aneurysms. 15 of the 85 patients (18%)required pre-operative embolization of one (n=13) orboth (n=2) of the hypogastric arteries. The patient pop­ulation included 13 men, 2 women: age 52 - 83 years(mean=72 years). We retrospectively reviewed the inci­dence of buttock claudication, and bowel or bladderdysfunction. Follow-up was from 1-24 months post-pro­cedure and included a review of medical records, clini­cal visits, and follow-up phone interview.

Clinical Outcomes Following Hypogastric ArteryCoil Embolization Prior to Stent-Graft Treatmentof Abdominal Aortic Aneurysms.c.c. Massin, William Beaumont Hospital (Radiology),

Royal Oak, MJ, USA • M. Kirsch • R. Salem •

W Romano • P Bove • G. Long, et ai,

PURPOSE: To evaluate the potential ischemic complica­tions following hypogastric artery embolization prior tostent-graft treatment of abdominal aortic aneurysms.

No other patient developed a complication related toembolization.

Abstract No. 1383:56 pm

MATERIALS AND METHODS: From December 1997 toJuly 2000, 75 patients underwent stent-graft repair foran AAA and five for an iliac aneurysm. Of these, 25 pa­tients required embolization of 27 lIAs, Embolizationprocedures were performed at least 24 hours beforestent-graft repair. All lIAs were embolized to completeocclusion with a combination of coils plac,ed at the lIAbifurcation, and gelatin sponge, Patients were followedfor 2-33 months for evidence of complications.

RESULTS: The mean age and average aneurysm size offemale patients (78 yrs and 5.53cm) was not signifi­cantly different from male patients (74 yrs and 5.8cm).Both subsets of patients included bifurcated, aortouni­lateral and tube graft devices from many vendors. MeanCIA and EIA diameters were 12.5 mm and 7.9mm re­spectively in females; versus 15,3mm and 9,2mm inmales. In female patients ~here were 15 complex iliacaccess events including vessel dissection or rupture (5),chimney delivery (2), PTA (6) and failed device inser­tion (1) arising in 10 of the 57 patients (17.5%) approx­imately double the rate of the male counterparts (9,8%),The percentage of patients with aneurysm sac shrinkage(greater than 90 day CT follow-up) was nearly equiva­lent in both groups (40.4% to 38,4%),

856

RESULTS: Unilateral buttock claudication developed inone patient following unilateral ITA embolization. Bilat­eral buttock claudication developed in a further patientfollowing bilateral embolization: claudication occuredin 8% of patients, 11% of lIA embolizations. One furtherpatient had a laparotomy 10 days following unilateralITA embolization (9 days post stent-graft) for sigmoidperforation. Pathology of resected bowel revealedatheromatous embolization: this was more likely causedby the stent-graft procedure than the IIA embolization,

Endografts for Emergency and Elective ThoracicAortic Aneurysm.K.R. Thomson, The Alfred, Prahran, Australia·

P. Y Milne • Pj. Mitchell. N K. Atkinson •WA. Campbell. j. Goldblatt

PURPOSE: To assess endografts in the thoracic aorta fortraumatic and other less urgent aneulysms.

MATERIALS AND METHODS· Patients were selected forthoracic endografts based on either medical comorbid-

RESULTS: Endografts were deployed successfully in allcases with follow-up from 1 to 40 months. Three en­doleaks were seen following deployment. One was em­bolised immediately, one sealed during follow-up andone is being followed. In two patients the entire de­scending aorta was covered by the endograft. In one ofthese the procedure was complicated by stroke, para­plegia. bowel ischaemia and death. The subclavian ar­tery has been sacrificed in two patients because of acritically short aneurysm neck. In one of these patientsa prior carotid to subclavian bypass was performed. Inall but two patients, the aneUlysm has shrunk to the en­dograft within six months.

CONCLUSION: Aortic endografts are useful for con­tained aortic rupture and elective aneurysm repair in pa­tients for whom a thoracotomy poses unacceptable risk.

ity or in the acute trauma setting, because of issues ofanaesthesia and surgical access. Six patients with con­tained traumatic rupture of the aorta received urgentendografts and eight patients were treated electively. Inthe patients with rupture, measurements were made im­mediately before graft placement and endografts ofstandard length with various diameters were availablefrom department shelf stock. The endograft diameterswere oversized by 2-4 mm. Elective endografts werecustom made in varying diameters and lengths depend­ing on clinical need. All endografts were inserted in theangiography suite with femoral access under generalanaesthesia. Adenosine cardiac arrest was used for 12 ofthe cases during initial deployment and subsequent bal­loon expansion. In eleven patients a commerciallyavailable endograft designed specifically for the tho­racic a011a was used (Cook Australia).

Endoluminal Treatment of Ruptured AbdominalAortic Aneurysm with Small IntestinalSubmucosa Sandwich Endografts: An

Experimental Study in Sheep.K. Yamada, Dotter InterventionalInstitttte, Oregon

Health Sciences University, Portland, OR, USA •D. Pavcnik • B.T. Uchida· H.A. Timmermans •c.L. Corless • K. Yamakado, et at.

PURPOSE To evaluate efficacy of small intestinal sub­mucosa (SIS) Sandwich endografts for treatment ofacute rupture of abdominal aortic aneurysms (AAA) andto explore the reaction of aorta to this material.

il1.ATERlALS AND METHODS: In 8 adult sheep, an in­frarenal AAA was created transluminally by dilation of ashOl1 Palmaz stenl. In 6 sheep, the aneurysm was thenruptured by overdilation of the stent with a large angio­plasty balloon. Two sheep with AAA that were nor rup­tured served as controls. SIS Sandwich endograft, con­sisting of a Z stent frame with 5 bodies and coveredinside and out with SIS, was used to exclude the lUp­ture and non-ruptured MAs. Follow-up aortographywas done immediately after the procedure and before

Abstract No. 1424:40 pm

Aortoillac Anatomy by Virtual Angioscopy: Use in

Pre-operative Planning for EndovascuJar Repair ofAbdominal Aortic Aneurysms.E.M. Walser, University ofTexas Medical Branch,

Galveston, TX, USA • R.P. Johnson, Jr. • V. T. Le

sacrifice at 4, 8, or 12 weeks. Autopsy and histologicstudies followed.

RESULTS: Endograft placement was successful in aU 8sheep. Both ruptured and non-lUptured MAs were suc­cessfully excluded. Three animals with MA rupture de­veloped hind leg paralysis due to compromise of arte­rial supply of lower spinal cord and were sacrificed oneday after the procedure. In five animals, three with rup­ture and two controls, follow-up aortograms revealedno aortic stenoses and no perigraft leaks. Gross and his­tologic studies revealed incorporation of the endograftsinto the aortic wall with replacement of SIS by denseneointima that was completely endothelialized in areaswhere the endograft was in direct contact with the aor­tic wa II. In central portions of the endograft in contactwith the thrombosed aneurysm, endothelialization wasincomplete even at 12 weeks.

CONCLUSION: The SIS Sandwich endografts effectivelyexcluded simple AAAs and ruptured MAs. They wereincorporated into the aortic wall.

PURPOSE: To investigate the ability of CT virtual an­gioscopy to select a vascular access site for subsequentendovascular stent-graft repair of abdominal aorticaneurysm.

MATERTALS AND METHODS: Ten patients with abdomi­nal aortic aneUlysm had preoperative spiral C1' scans.Data were manipulated using a GE Advantage WindowsSparc workstation and virtual endoscopy software (Nav­igator) to create virtual angioscopy. Arterial "f1y­throughs" were constructed from both groins to the levelof the renal artery ostia and evaluated for luminal diam­eter, presence of calcific plaques, and arterial tortuosity.These imaging parameters were retrospectively corre­lated with the subsequent stem graft procedure and theease or difficulty of device insertion and placement.

RESULTS: With appropriate thresholding for contrastand calcium, virtual angioscopy provided excellent en­doluminal anatomy, predicting adequacy of arterial ac­cess and identifying potentially treatable areas of steno­sis prior to endovascular repair of abdominal aneurysm.Femoral and iliac anatomy unfavor2ble for stent-graftinsertion was readily apparent using CT-angioscopy.

CONCLUSION: CT-angioscopy provides a valuablepre-procedure roadmap of arterial endoluminalanatomy for planning subsequent endovascular stentgraft procedures. 857

Abstract No. 1414:29 pm

PURPOSE: to demonstrate the feasibility and versatility ofendoluminal treatment concepts in aortic emergencies.

MA7ERlALS AND ME11-JODS The post procedure imag­ing studies on 19 patients who underwent endovascularstent graft placement for treatment of abdominal aortic

Emergency Stent-Graft Treatment of AorticAneurysm and Dissection.

G.M. Richter, University Hospital Heidelberg, Heidelberg

69120, Germany • H. Schumacher· JI Hansmann •JR. Allenberg

DISCUSSION our experience demonstrate the feasibilityof treating aortic ruptures or dissections by endoluminalstent-grafts in severe emergency settings. As a result ofthe highly critical presentation status the mortality is stillconsiderable (2/13 p.). Nevertheless, the overallfavourable outcome in the majority of the patientsshould encourage a faster application of percutaneousstent-grafts in aortic emergencies.

Abstract No. 14512:30 pm

Wednesday, March 7, 200112:30 pm-2:00 pm

Scientific Session 19RenalNisceral/Gastroilltestinal VascularInterventionsModerator: Jeet Sandhu, MD

SuperseJective Arterial Embolization for theTreatment of Acute Lower Gastrointestinal

Hemorrhage.R. Bandi, Henry F01"d Hospital, Detroit, J'It11, USA •

PC Shetty • R. Sharma • M. Bw"ke • T. Burke

PURPOSE: To evaluate the technical feasibility & effi­cacy of hemostasis; recurrent bleeding & ischemia re­sulting from superselective embolization of acute lowerGI hemorrhage.

MA1ERlALS AND METHODS: 52 superselective mysen­teric artery catheterizations were undertaken in 48 pa­tients with angiographic evidence of lower GI bleed­ing.Embolization was performed only if the arterialrecta leading to the bleed could be successfullycatheterized.Embolization was successful in 39

aneurysm (AAA) were retrospectively reviewed. Duplexultrasound was performed by an experienced vascularsonographer using a 3.5MHz transducer (An Ultramark9). cr images were acquired (IGE high speed cr) be­fore and after intravenous contrast administration(l50mls iodixanol 320mglml delivered by pump injec­tor at 4mls/sec). The results of the imaging studies werecompared for the presence of endoleaks.

RESULTS: Of the 19 patients, four had cr follow uponly, and two patients records could not be traced:these were excluded from the analysis. In the remaining13 patients a total of 34 cr and 52 US examinationswere performed at regular post procedure intervals.The median follow-up time for CT was 10 months(range 5 days-36 months) and for US was 12 months(range 5 days-44 months). A total of 11 endoleaks wereidentified in 7 patients. Seven endoleaks were identifiedon both cr and US images. One endoleak was seen onUS and proceeded directly to confirmatory angiographyand three endoleaks were only identified on cr images.In this latter group there were limited views of the ab­dominal aorta because of patient habitus and overlyingbowel gas.

CONCLUSION In most patients duplex ultrasound is aseffective as cr scanning in the long term follow-up ofpatients after insertion of abdominal aortic stent grafts.In patients where ultrasound views are suboptimal, re­course to cr scanning may be necessary. Use of duplexultrasound as the sole method of follow-up after aorticstent grafting avoids the large radiation dose of cr ex­amination and may be more cost effective.

Abstract No. 144

Abstract No. 143

5:02 pm

4:51 pm

Comparison of CT and Duplex Ultrasound in theFollow-up of Patients after Aortic Stent Graft

Placement.C Sandhu, St Georges Hospital, London, United

Kingdom • R. Morgan • K. Khaw • ]. Danaher •C Engelke • A.M. Belli

PURPOSE: To compare the effectiveness of cr and du­plex ultrasound (US) in the detection of endoleaks fol­lOWing endovascular aortic stent graft placement

RESULTS: in all patients the graft placement was suc­cessful (= correct placement, complete aneurysmal oc­clusion, stop of bleeding) without technical complica­tions. However, two patients died during the first monthof follow-up, one from delayed hemorrhagic shock(AAA patient) and the other from ischemic multiorganfailure and sepsis (type B dissection), respectively. The11 surviving patients had an' average of 8 days of emer­gency suite stay and a total of 17 days of hospital smy.Their mean survival is 11 months C3 - 37 months). Sofar, in none of the aneurym patients hemorrhage reoc­cured. The surviving patient with type B dissection hadan uneventful follow-up without further ischemic organcomplications.

MA1ERlALS AND METHODS: During the last 4 years wehave treated a total of 13 patients suffering from life­threatening aortic emergencies (asa score· 4) by endo­luminal placement of stent-grafts. Five patients had aruptured abdominal (spontaneous), six a ruptured tho­racic aortic anetliym C3 spontaneous, 3 trauma inducedruptures from motor accidents) and two patients had is­chemic complications from type B aortic dissectionsand true lumen collapse of the abdominal aorta. In 8patients the Excluder system (Gore company) was usedand in five the Talent device (Medtronic company).

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