MATERIALSAND METHODS: 21 patients were referred tothe Interventional radiology service between 1197 and 6/02for evalllation of hypervasclllar mass in the kidney. Thesewere thought to be tumor or aneurysm on uJtrasound or CT. 8patients had hematuria, l had high output failure and lasymptomatic patient had an abdominal bruit on physicalexam. 6 patiems had a history of hypertension. Renal functionwas not compromised in any patient. There was no antecedenthistory of percutaneous or endourologic renal intervention.SeJective renaJ angiography was performed whichdemonstrated a diagnosis of Angiomyolipoma in 3 patients.lO patients had a renaJ artery aneurysm. 8 patients had a highflow AV fistuja with a singJe hypertrophied feeding arteryand aneurysmally diJated veins. These dilated veins were oftenmistaken for renaJ artery aneurysms or hypervascular masson CT.

rena I function was not demonstrated in patients treated withunilateral disease versus globaJ d.isease (bilaterai renal arterystenosis or stenosis to a soli tary kidney) (P=0.14). Meanfollow-up was 18 months (1-42 months) for al! patients.

CONCLUSION: In patients with RAS and rena) insufficiency,PTRA ± RAST resulted in improved long-term renal functionfollowing treatment ofhigher degrees of stenosis compared totreatment of lesser degrees of stenosis above 50%. Treatingunilateral disease in patients with high degrees of stenosisresulted in similar long-term results in renal function comparedto patients with global disease and high degrees of stenosis.

Scientific Session 8Hemodialysis Access Preservation

RESULTS: 7/8 patients underwent superselectiveemboJization of the feeding artery with complete resoJution.Coils were used in 4 patients and coiJs and NBCA liquidadhesive were used in 3 patients. l patiem did not undergoembolization, as the feeding vesseJ could not be seJectiveJyexcluded from the renal circulation. Follow up CT scans havedemonstrated continued exclusion of these fistulae. Hematuriahas resolved in all patients.

CONCLUSION: Endovascular embolization offers safemanagement for idiopathic renal AV fistula. It should be notedthat all of these lesions occurred in the right kidney andparticularJy the upper pole. This lesion should be consideredwhenever any aneurysmal type of mass of the right kidney isencountered.

Percutaneous Renal Revascularization for IschemicNephropathy: What Degree of Stenosis Is Signiticant?D.J. Spinosa, University ofVirginia Health System,Charlottesville, VA, USA. A.H. Matsumoto • E.A.Bissonette .l.F Angle • K.D. Hagspiel • D.A. Leung, et al.

PURPOSE: To determine the effect of varying degrees ofrenal artery stenosis (RAS) on renal function folIowingpercutaneous transJuminal renaJ angioplasty (PTRA) andlorrenaJ artery stent therapy (RAST) in patients with ischemicnephropathy.

MATERIALS AND METHODS: Ninety-six consecutivepatients undergoing PTRA ± RAST comprised the studypopulation. The degree of stenosis for each renal artery wasdetermined from angiographic images assessed independentlyby five experienced interventional radiologists. The averagevalue of the five scares for each renal artery determined thedegree of renal artery stenosis in each patient. Ali patientsdemonstrated at least 50% d.iameter stenosis in at Jeast onemain renal artery. Renal function was determined by measuringserum creatinine (Cr) within 24 hours priar to the procedure,and prospectively following the procedure at 48 hours, onemonth, and at 3 month intervals thereafter. Post procedureserum creatinine values were analyzed by comparing the changein the reciprocal creatinine (1/Cr) level versus time for varyingdegrees of stenosis.

RESULTS: A generalized linear model was developed tosummarize renal function over time. The slope of renal functionwas related to the pretreatment degree of RAS (P = < .01).Comparison of renaJ function expressed as lICr versus timedemonstrated improved renal function for patients in the 75thpercentile (78% diameter stenosis) compared to deteriorationin renal function for patients in the 25th percentiJe (61 %diameter stenosis) (P = 0.001). A significant difference in

2:14PM Abstract No. 70

Saturday, March, 29, 200312:30 PM - 2:30 PMModerator(s): Mare R. Sapoval, MD

Thomas M. Vesely, MD

12:30 PM Abstract No. 71

Multicenter Phase I Results ofthe Bard PTFE Stent GraftTrial for Hemodialysis Venous Anastomotic GraftStenoses.Zl. Haskal, NewYork Presbyterian Hospital/Columbia,New York, Nr, USA • T. Vesely • E. Sehuman • G.McLennan • F Rivera • S. Belman, et al.

PURPOSE: To assess safety and efficacy of apolytetrafluoroethylene (PTFE) encapsulated nitinol stent(Bard Peripheral Vascular) designed for treatrnent of failingdialysis access graft with venous anastomotic stenoses.

MATERIALS AND METHODS: Study design is a 15 centernon-randomized cohort of roll-in patients as prelude to arandomized trial against PTA. Enrol1ment: 32 patients, (meanage 62y, r, 37-84), (lI male121 female). Graft locationsincluded: 19% (6/32) forearm, 62% (20/32) upper arm, and19% (6/32) forearm with jump to upper arm. There werepriar interventions at current treated venous anastomosis in56%. Results were assessed by graft function (National KidneyFoundation recommended criteria), and 2, 6 month protocolvenography. Core lab film analysis was performed.

RESULTS: Forty-two devices were implanted (1.4/patient),with overlapping devices in 9 cases. Twenty-six flared, 16straight stent-grafts were used. Average treated Jesion Jengthwas 3.3 cm (r, 0.4-7.0 cm), mean percent stenosis 70% (r, 51­91). Mean angle of anastomosis was 22 degrees (range O to70). Technical (deployment), anatomic «30% residualstenosis), and hemodynamic (resolution of dysfunction)success were 100%. At 2 months, primary patencies of treatedarea and access circuit: 87% (20/23) and 83% (19123);secondary patency: 100% (23/23). l death occurred at 2 mos.,unrelated to device. At 6 months, primary patency ( < 50%stenosis) of treated venous anastomoses was 72% (13/18)and access circuit was 61 % (11118); secondary patency: 100%(18118).

CONCLUSION: This PTFE encapsulated stent graft is safeand improves patency of venous anastomotic stenoses inhemodialysis patients.

525

MA TERIALS AND METHODS: PTFE grafts were placed in 5castrated juvenile male pigs, 30 to 40 kg, from either the rightor left iliac artery to the ipsilateral iliac vein and the animalswere sacrificed on day 7 after graft placement. 5-Bromo-2'-

Effects of Low Wall Shear Stress in PorcinePolytetrafluoroethylene Hemodialysis Grafts.S. Misra, Maya Clinic Rachester, Rachester, MN, USA. D.Waadrum • J. Hamburger. J. Glack.ener • V. Barocas • V.Miller, et al.

PURPOSE: The central hypothesis is blood flow throughpolytetrafluoroethylene (PTFE) hemodialysis grafts resultsin abnorrnal flow pattems including foci of decreased wallshear stresses (WSS) at the venous anastomosis. These fociof decreased WSS are associated with an INCREASE inexpression and secretion of matrix metalloproteinase 2 and 9(MMP-2 and MMP-9) facilitating proliferation and migrationof adventitial cells leading to a stenosis at the venousanastomosis.

Celi Source and Celi Kinetics in Porcine HemodialysisGrafts.S. Misra, Maya Clinic Rachester, Rachester, MN, USA. M.Daherty • J. Hamburger. S.L. Nyberg • V. Miller

PURPOSE: Develop and validate a porcine hemodialysis graftmodel of venous stenosis formation and test the hypothesisthat the source of early proliferating celis in venous stenosesis the adventitia, and, that migratioIi of these celis is greatestwithin the first 2 weeks after graft placement.

MATERIALS AND METHODS: Polytetrafluoroethylenegrafts were placed in 25 castrated juvenile male pigs, 30 to 40kg, from either the right or left iliac artery to the ipsilateraliliac vein. Two animals were used to optimize the surgery.The remaining animals were sacrificed on D3 (day 3, n=6), D7(day 7, n=5), D14 (day 14, n=6), and 019-26 (days 19-26,n=6) after graft placement. 5-Bromo-2'-deoxyurictine (30 mg!kg) was given intravenously at 24 and 48 hours after surgery.Venous stenotic tissue and contralateral iliac vein (controI)from only patent grafts were immunostained with hematoxylinand eosin (H & E), proliferating celi nuclear antigen (PCNA),and BrdU. Quantitative morphometric image analysis wasperforrned.

RESULTS: There were 8 graft thromboses- l at D3, l at D7,2 at D 14, and 4 at D 19-26. Venous stenoses formedreproducibly at the vein-to~PTFE anastomosis ranging from10.5% to 58% (mean=27.3%). At day I and 2 post graftplacement, dividing cells in S phase were labeled by BrdU. ByD3 to D7, immunostaining for BrdU positive cells had peakedin the adventitia. By D14 to D19-26, adventitial BrdUimmunostaining decreased as these cel!s started to migrate tothe media. At D3, medial BrdU immunostaining had increased,by D7 it had peaked and subsequently decreased by D14 toD 19-26 as celis started to migrate to the intima. BrdUimmunostained positive cells peaked at D19-26 in the intima.At D3, PCNA immunostained positive cel! peaked in themedia, by D7, in the intima, and by D14, in the adventitia.

CONCLUSlON: In the porcine hemodialysis graft stenosismodel, venous stenoses form reproducibly. These resultsindicate that the adventitia and media are involved in celisource and celi migration resulting in venous stenosistherapeutic targets for limiting venous stenosis formationwithin the first 2 weeks of graft placement. <::nłIU"

Matrix Metalloproteinase 2 and 9 Activity in VenousStenoses in Porcine Hemodia]ysis Grafts.S. Misra, Maya Clinic Rachester, Rachester, MN, USA. D.Waadrum • J. Hamburger. S. ElkotLri • J. Glack.ener • V.Miller

PURPOSE: In porcine polytetrafluoroethylene hemodialysisgrafts, increase in expression and secretion of matrixmetalloproteinase 2 and 9 (MMP-2 and MMP-9) facilitatesproliferation and migration of adventitial cells leading to astenosis at the venous anastomosis.

Abstract No. 74

MATERIALS AND METHODS: Polytetrafluoroethylenegrafts were placed in 6 castratedjuvenile male pigs, 30 to 40kg, from either the right or left iliac artery to the ipsilateraliliac vein. The animals were sacrificed on D3 (day 3, n=2), D7(day 7, n=2), DI4 (day 14, n=2), and D19 (day 19, n=I), andD26 (day 26, n=5) after graft placement. 5-Bromo-2'­deoxyuridine (30 mg/kg) was given intravenously at 24 and 48hours after surgery. Venous stenotic tissue and contralateraliliac vein (controI) from only patent grafts were irrununostainedwith hematoxylin and eosin (H & E), proliferating celi nuclearantigen (PCNA), and BrdU. Quantitative morphometric imageanalysis was performed. Zymography was performed forboth the stenotic and controI veins and the relative amountsof the pro MMP-9, MMP-9, pro MMP-2, and MMP-2were determined as a function of time. Angiography withtransonic ultrasound or phase contrast MRI was perforrnedprior to sacrifice.

RESULTS: MMP-9 activity peaked at D7 while MMP-2activity increased but occurred late at DI9-26. Celi rnigrationas measured by BrdU index peaked at D3-D7 in the adventitiaand decreased as cells migrated from the adventitia to themedia and intima. Cel! proliferation as measured by PCNAindex at D3 was greatest in the media and at D7 in the intima.Percentage ofstenosis at D3 ranged from 10.5 to 21.75, at D7,25-40.6%, at D19, 30.6%, and at D26, 58%. QARftl

RESULTS: There was 1 graft thrombosis at D7. At WSS =625 dynes/cm2 when compared with WSS = 2532 dynes/ cm2,

there was increased MMP-9 activity with some increase inMMP-2 activity. Celi migration as determined by the BrdUindex. At low WSS (132 and 625 dynes/cm2), there wasincreased celi migration when compared to higher WSS (1290and 2532 dynes/cm2

). Celi proliferation as deterrnined by thePCNA index showed that at low WSS (1625 and 1290 dynes/cm2

), there was increased celi proliferation when compared tohigher WSS (2532 dynes/cm2).

CONCLUSlON: Although observed in a smali number ofanimals, collectively, these data support tbe hypothesis thatlow WSS maybe responsible for increased celi migration, cellproliferation, and MMP-9 activity in porcine PTFEhemodialysis grafts. OlmlF'

1:03PM

deoxyuridine (30 mg/kg) was given intravenously at 24 and 48hours after surgery. Venous stenotic tissue and contralateraliliac vein (controI) from only patent graftS were immunostainedwith hematoxylin and eosin (H & E), proliferating celi nuclearanrigen (PCNA), and BrdU. Quantitative morphometric imageanalysis was performed. Zymography was performed todetermine MMP-2 and MMP-9 activity. Angiography andtransonic ultrasound was performed prior to sacrifice andimmediately after graft placement in the first 2 animals andphase contrast magnetic resonance imaging and magneticresonance angiography in the last 3 animals. Wall shear stresswas estimated from Poiseuille's Law.

Abstract No. 73

Abstract No. 72

12:52PM

12:41PM

S26

CONCLUSION: MMP-9 may be responsible for celimigration while MMP-2 may be responsible for celiproliferation. Targeting these proteins may limit stenosisformation in hemodialysis PTFE grafts.

% PARP Cleavage by Vein Seclion (Open Grafts)lliac Bffurcalion Outllow Slenosis Anaslomosis Below Graft

1day 40.9 ffi 75 51.6 49.91wk 69.6 52.3 48.4 SI2wk 51.8 64.5 63 61.6 434wk 43.3 55.9 54.5 66.6 ffi

Apoptosis in Venous Stenoses Associated withHemodialysis Grafts.G. McLennan, Indiana University Medical Center,Indianapolis, IN, USA - F. Aladham - G. Carlos - K. Kerr- W Watson - S.G. Lalka, et al.

PURPOSE: To assess the presence of apoptosis in veinsassociated with arteriovenous conduits.

527

Abstract No. 771:36PM

MATERIALS AND METHODS: Polytetrafluoroethylenegrafts were placed in 16 castrated juvenile male pigs, 30 to 40kg, from either the right or left iliac artery to the ipsilateraliliac vein. The animaJs were sacrificed on D3 (day 3, n=4), D7(day 7, n=3), D 14 (day 14, n=4), and D26 (day 26, n=5) aftergraft placement. PC MRI with MRA was performed one dayprior to sacrifice of the animals. The accuracy andreproducibility of the PC MRI was assessed with the use ofa flow phantom. Wall shear stress was estimated at the venousanastomosis and contralateral iliac vein (control) fromPoiseuille's Law after calculating the Reynolds number toensure there was laminar flow. Amount of stenosis wasdetermined from the MRA data.

RESULTS: There were 8 graft thromboses: 1 at D3, 1 at D7,I at D 14, and 5 at D26. In 2 animals, I at D3 and 1 at Dl 4, nostenosis developed. Flow measurements could be accuratelymeasured in 4-millimeter diameter vessels. At D3, flow in thegrafts ranged trom 785.4 to 1745.4 ml/min; atD7, flow rangedtrom 1111.8 to 1234.2 mL/min; and at D14, flow ranged from454.2 to 748.2 mUmin. Reynolds number ranged between 5­30. At D3, WSS at the venous anastomosis ranged from 1403to 2405 dynes/cm2

, at D7, WSS ranged from 1291 to 2532dynes/cm2, and D14, WSS ranged from 460 to 2877 dynes/cm2. At D3, the amount of stenosis ranged trom 8.96 to 62%,at D7, from 24.5 to 40.6%, and D14, from 51 to 73%.

CONCLUSJON: The amount ofWSS and amount of stenosiscould not be predicted simply by the duration (length) ofgraft placement. PC MRI with MRA can be used to accuratelymeasure flow and evaluate angiographic morphometric data inporcine hemodialysis grafts. QRIHl

Łyse and Wait Thrombolysis oC Dialysis Grafts UsingCath·Flo TPA in a Freestanding OutpatientInterventional Center.J.D. Lutz, Radiology Associates ojSan Antonio, PA, SanAntonio, TX, USA - S.A. Zepeda

PURPOSE: To report our initial experience with Iyse andwait thrombolysis of thrombosed dialysis grafts using cath­flo TPA in a freestanding, radiologist-owned outpatientinterventional center.

MATERIALS AND METHODS: Retrospective review andanalysis of 153 thrombolysis procedures perforrned on 99consecutive selected patients referred from nephrologists inoutpatient dialysis clinics to a freestanding outpatientinterventional radiology center for therapy (thrombolysis andpossible graft intervention) during the 6-month period fromNovember 1,2001 until April 30, 2002. When appropriate,standard Iyse and wait technique was utilized for thrombolysisusing cath-flo TPA solulilized with 3000 units of heparin, ±fogarty balloon mobilization ofthe arterial plug. Subsequentrevision consisted ofPTA or surgery as indicated by invasivepressure measurements and anatomic considerations onfistulagram. Success (restoration of adequate flow andcompletion of at least one uncomplicated dialysis treatment),DOQI standards for patency, need for temporary catheterplacement, tum around time, costs, reimbursements, andpatient satisfaction were monitored. Telephone and chartfollow-up was performed for a minimum of 90 days post­procedure, corresponding to the global period.

RESULTS: Technical success (restoration of flow and graftrevision able to support at least one successful dialysistreatment) was 94%. At 90 days post procedure, clinicalsuccess was as follows: primary patency was 56%, assistedprimary patency was 59%, secondary patency was 93%, and

Abstract No. 75

Abstract No. 76

1:14PM

1:25PM

MATERIALS AND METHODS: 4mm arteriovenous graftswere created between the iliac artery and vein on one side of14 outbred swine. A sham operation was performed on thecontralaterallimb. Animals survived for I-day (n=4), 1 week(n=2), 2 weeks (n=4), and 4 weeks (n=4). 4 grafts wereoccluded at the time of sacrifice (2 1-day, 1 2-week, and 1 4week) At sacrifice; the vessels were studied with arteriography,venography, and intravascular ultrasound (IYUS) andexplanted. Yeins were sectioned into 4 or 5 sequential sectionsfrom the iliac bifurcation to the vein below the graft. WesternBlots were performed on celi Iysates and stained for Poly(ADP-ribose) Polymerase (PARP). Cells undergoing apoptosiswill cleave PARP from its 116 kD form to its 89 kD form.PARP cleavage is specific for cells undergoing apoptosis. Thepercentage of PARP cleavage was calculated from eachspecimen & compared by time of maturation, location alongthe vein, and for the presence or absence of the graft.

RESULTS: Percent stenosis decreased from 77.7 ±2.5% at 1day to 35 ±29.4% at4-weeks in open grafts. Western blottingdemonstrated increased PARP cleavage at the stenosis overtime with a mean PARP cleavage increasing trom 34.3 ± 25.6%at 1 day to 48 ± 14.7% at 4 weeks. In occluded grafts, thepercent stenosis decreased from 36.9 at I day to 21.6% at 4weeks while PARP cleavage decreased from 51.8 % to 44.3%.Stenoses of the sham vessels decreased trom 34.4 ± 21.7% at1 day to 25.1± 13.7% at 4 weeks while PARP cleavageincreased from 24.9% to 50.9%. PARP Cleavage tended to begreatest from the anastomosis to the outflow vein (see table).

CONCLUSION: Apoptosis is present in veins associatedwith arteriovenous conduits. Surgical sham operations alsoinduce apoptosis and healing from the operation results inincreased PARP cleavage over time. Increased apoptosis isassociated with a decrease in % stenosis.

Phase Contrast Magnetic Resonance Imaging in PorcinePolytetrafluoroethylene Hemodialysis Grafts.S. Misra, Mayo Clinic Rochester, Rochester, MN, USA -J.Homburger - 1. Glockener - S. Elkouri - V. Barocas - V.Miller, et al.

PURPOSE: Phase contrast (PC) MRI with MRA is anoninvasive technique that allows an angiogram and flowmeasurements to be obtained in a short period of time. Thefeasibility, accuracy, and reproducibility of using PC MRIwith MRA in a porcine hemodialysis graft model was assessedfor use in measuring wall shear stress (WSS)and flowmeasurements.

MATERIALS AND METHODS: An ongoing prospectivestudy is made of36 patients with dysfunctional PTFE dialysisgrafts. With an FDA investgational device exemption,indications for SMART stent placement were 1»30% residual

CONCLUSION: This new balloon may promise to offer amore effective and sustained result from fistuloplasty in nativeAVFs. It appears to be less locally traumatic or painful thanstandard techniques. Our preliminary experience mayaIsosuggest that proximal stenoses respond well. Longer-termsurveillance is planned.

SMART Stent Use Following Angioplasty Failure inDialysis Access Venous Stenoses.p. V.M. Vogel, Sutter MedźcalCenter, Sacramento, CA, USA

PURPOSE: To deterrnine the safety and efficacy of the nitinolSMART stent, used following angioplasty failure inhemodialysis access venous stenoses.

Use of a Cutting Ballooo To Treat Recurrent andResistant Stenoses of Native Hemodiałysis ArteriovenousFistułas.

K. McBride, Royallnfirmary ojEdinburgh, Edinburgh,Scotland, UK • D. Cookson • M. Warren. J. Goddard

PURPOSE: To determine the effectiveness and durability of anew peripheral cutting balloon ( PCB ) (Boston Scientific ) totreat recurrent and resistant stenoses within the venousoutflow of native arteriovenous hemodialysis fistulas (AVFs).

Abstract No. 802:09PM

MATERIALS AND METHODS: Using a quality assurancedatabase, records from 117 hemodialysis access interventionswere retrospectively reviewed. IRB exemption was obtained.Only interventions on grafts were included. The databaseiocluded PE (thrill [T], thrill with slight pulsatility [TSP],pulse with slight thrill [PST], pulse [P]) at three locationsalong the graft (proximal, mid, distal), VLP/S calculated bothusing S from a BP cuff (S'uff) as well as within the graft withoutflow occluded (Sd ), graft configuration and location,indication, operator a~d'time to next intervention (outcome­primary patency). Only procedures with complete follow­up data were included in the analysis (n=98; declot, n=51;prophylactic PTA, n=47). Statistical analysis was performedusing Cox proportion hazards regression.

RESULTS: Graft configuration, location, side, VLP, Sd ' andS rr did not affect outcomes. An operator effect was n~t.;d for2'physicians and was adjusted for in all analyses. Pressureratios were weak predictors of outcome (VLPI Sd ' p=0.066;VLPI S'ull' p=0.078) and suggested patency in~~~ased withincreasing pressure ratio, contrary to prior studies. Proceduretype predicted outcome (declot median patency 50 days versus

Physical Examination Versus Pressures for PredictingOutcomes of Hemodiałysis Access Ioterventions.p. Ponce, University ojPennsylvania Medical Center,Philadelphia, PA, USA • S. O. Trerotola • S. W Stavropoulos• T. WI. Clark • c.M. Tuite. J. Mondschein, et al.

PURPOSE: Intragraft venous limb to systemic pressure ratio(VLP/S) has been proposed to help determine the endpoint ofhemodialysis access interventions. We hypothesized thatphysical examination (PE) of the access could be used in thesame way, and compared these techniques as predictors ofoutcome.

stenosis following angioplasty, 2) Less than two monthrecurrent stenosis in a peripheral vein or less than three monthrecurrent stenosis in a central vein following angioplasty, 3)Post angioplasty mid-graft systolic pressure ratio >.4, withlocalized venous obstruction, and 4) venous rupture. Patientdemographics, access characteristics, stenosis length andlocation, post intervention residual stenosis, and graftpressures were studied. Primary patency of the treatedobstruction was defined as a functioning access, withoutrecurrent thrombosis, elevated venous pressure, arm swelling,or low access flow, depending on the reason for initial referral.Life tables were constructed using Kapłan Meier method.

RESULTS: Seven patients received stents for >30% postangioplasty stenosis, 3 for rapidly recurrent peripheral venousstenosis, and one for venous rupture following angioplasty.Graft age, number of stenoses, number of prior interventions,and incidence of diabetes did not differ (p>.05) between theangioplasty and stent groups, but there were significantlymore upper arm grafts in the stented group. The treated stenosiswas at the venous anastomosis in 96% of angioplasty and91 % of stent patients. Stented lesions had a greater meanstenosis severity and length (74%/3.3cm) than lesions thatresponded to angioplasty (65%/2.2cm) (p=.017, for both).Post intervention stenosis was significantly less in the stentgroup (7%vs. 15% (p=.006), but the mid graft systolic pressureratio did not significantly differ. Median primary patencywas 130 days for angioplasty, and 325 days for stent patients(p=.08). There have been no complications of stent placement.

CONCLUSION: The SMART stent is safe and effective fortreating residual or rapidly recurrent stenosis followingangioplasty. Preliminary data show a trend for improvedpatency over angioplasty.

Abstract No. 79

Abstract No. 78

1:58PM

MATERIALS AND METHODS: From March 2002, 10patients ( 6 małe ), aged 26 - 68 years ( mean = 54 years ),underwent balloon dilatation ( PTA ) of venous stenosesaffecting 5 above-wrist and 5 above-elbow native AVFs. Sevenpatieots had recurrent, same site, steoosis ( with l to 4 previousPTAs ) and 3 required procedures to accelerate AVF maturation.Either a 6mm diameter ( n = 8 ) or a 4mm ( n = 2 ) PCB wasused. These have 4 attached blades which project 160 micronswhen the balloon is fully inflated. Urea reduction ratio(URR) was measured , and a11 cases had Doppler ultrasound,pre- and post-procedure.

RESULTS: Ali procedures were technically successful, with7 post-aoastomotic stenoses and 3 cephałic vein arch stenosestreated ( one with in-stent stenosis ). All procedures werewell tolerated and, subjectiveły, were less painful than standardfistuloplasty. Two balloons burst at 10 atmospheres onresistant lesions and 2 locał extravasations occurred, with nosequelae. Follow-up from l to 7 months ( mean 3 months )shows aU AVFs patent and functional, with significant increasein URR, in the 7 cases measured ( p < 0.02 ). Dopplerultrasound surveillance has found no episodes of recurrentstenosis to date.

tertiary patency was 94%. Temporary catheler placementwas necessary in 6% of patients. Major complications were lpost procedure transmural myocardial infarction resulting indeath 3 days post event. There were no graft infections duringthe surgical period. No patients required emergency surgery.No patient missed more than one dialysis session because oftheir thrombosed access, or any while awaiting therapy.

CONCLUSION: Lyse and wait thrombolysis of selectedthrombosed dialysis access fistulae in a freestanding outpatientinterventional center is technically feasible, safe, effective,cost effective, convenient therapy that results in acceptablepatient outcomes and high patient satisfaction.

1:47PM

528

CONCLUSION: ApproKimately 60% of all patients presentingwith rupture have infrarenal aneurysms. Based on aortic/iliaclfemoral diameter and lengths, 80% of all infrarenal rupturedAAA could be candidates for stent grafts.

Potential Application for Stent Grafts in RupturedAbdominal Aortic Aneurysms.S. Padia, Johns Hopkins Hospital, Baltimore, MD, USA.A. Arepally • L. Hofmann • G. Roseborough • M. Williams• B. Perler

Scientific Session 9Abdominal Aorłic Aneurysm:Endoprosthesis

Saturday, March, 29, 200312:30 PM - 2:30 PMModerator(s): Jeffrey Hull, MD

Mahmood K. Razavi, MD

529

Abstract No. 82

Abstract No. 83

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Learning Curve EtTect and Procedure-Related & LateOutcomes ofEndovascular AAA Repair (EVAR).G.J. Becker, Miami Cardiac & Vascular Institute, Miami,FL, USA. M. F. Kovacs • B. T. Katzen • J.F. Benenati • G.Zemel • A. Powell, et al.

PURPOSE: I) Identify factors influencing outcome ofendovascular AAA repair (EVAR) by applying the SVSreporting standards (J Vasc Surg 2002;35(5): 1048-60 & 1061­66) to a series analysis, 2) Exarnine "Iearning-curve" effect onEVAR procedure and outcomes.

MATERIALS AND METHODS: Study group: 437 consecutiveEVARs (mean AAA diameter of 5.75±1.lcm) from 3/94 to 8102 in a not-for-profit tertiary CV center. Reports of officevisits, procedures, imaging studies, lab values, computerizedmedical records, telephone followup, online Social SecurityDeath Index were analyzed. Measures: Implant success,adverse events, procedure-related mortality, proceduralefficiencies, LOS, and late survival. EVARs pre-FDA-approvalof 2 devices (10/99, n=157, Gpl) were compared to thosesince (n=280, GplI). Statistical analysis was done withStatsDirect v.I.9.5; significance was set at p<.05.

RESULTS: GpII v. Gpl EVARs were proportionately morefemale (11.4% v. 4.4%, p=.OI), similar in mean risk (1.45 v.1.48, p=.08), renal, cardiac, and pulmonary risk, but older(75.9yrs v. 73.5, p=.007), had less aR time (171 v. 145 min,p<.OOO I), tluoro time (32 v. 27 min, p=.OOOI), and contrastdose (223 v. I62cc, p<.OOOl). Deployment success was 4201437 (96.1 %); surgical conversions occurred in 7/437 (1.6%);10/437 (2.3%) were aborted. Deployment-relatedcomplications (DRCs) increased with risk stratification(p=.026), as did all procedure-related complications(p=.OO 19). Gp II had fewer DRCs, severe systemiccomplications, and all procedure-related complications(p=.017, p=.02, and p=.0005 respectively), and fewer daysin lCU (.62 v..28, p=.0006). Mean LOS was 2.35 for lowestand 5.11 d for highest-risk patients. Procedure-relatedmortality was 7/437 (1.6%), lower than predicted (2.3%­7.2%). Actuarial survival was 67% (5yr) and 65% (7yr). Mostof 70 late deaths were due to CV causes (n=26, including 3post-EVAR AAA ruptures) or cancer (n=19).

CONCLUSION: In this study, EVAR safety surpassed thatin published reports of open repair. Institutional learning­curve effect was demonstrated for aR time, fluoro time,contrast dose, DRCs, severe systemic complications, allprocedure-related complications, and LOS in the ICU. Latemortality was equivalent to that of open repair.

12:52PM

CTA as the Sole Angiographic Modality Prior to AAAEndografting.BL Dolmatch, UT-Southwestem Medical Center, Dallas,TX, USA • S. Josephs • F. Rivera • M. Jackson

PURPOSE: To assess whether computerized tomographicangiography (CTA) without digital subtraction angiography(DSA) was sufficient for pre-op abdominal aortic aneurysm(AAA) and iliac aneurysm characterization and endoprosthesissizing prior to endografting (EG).

MATERIALS AND METHODS: We reviewed all patients withAAAs who had CTA with or without DSA over a 17 monthperiod. CTA was performed on a Toshiba Aquillion 4 channelCT scanner with 3mm collimation and 1.5mm spacing, usinga Vital Irnages Vitrea-2 workstation for multiplanar reformationand 3-D volume renderings. Patients who did not undergo EGwere excluded as noted below. The EG group was divided into

Abstract No. 81

Juxtarenal74.56.833.3"1083.3"/0

Infrarenal68.4::fi41.4%93.1%

12:30PM

PURPOSE: To find potential stent graft candidates based onCT criteria in the setting of a ruptured AAA.

MATERIALS AND METHODS: A retrospective analysis wasperformed on a database in patients with the diagnosis ofruptures AAA over a 9 year period. Electronic medical recordswere reviewed for demographic data, type of aneurysmsoperative findings, length of stay, complications, and survival.Ali available CT scans for infrarenal andjuxtarenal aneursymswere reviewed. Standard stent graft measurements, includingproximal neck diameters, length of proximal neck, diametersof common iliac arteries, length from renal artery to commoniliac artery, diameter of femoral arteries and angulations ofaortic neck were performed with an electronic caliper. Mediandiameters, lengths and percentile quantification of themeasurements were performed.

RESULTS: 49 patients (38 males, II females) presented withrupturep AAA. Distribution of aneurysms were 29 (59%)infrarenal, 12 (24%) juxtarenal and 8 (16%) suprarenal.Seventeen CT scans were evaluated for stent graftmeasurements. In patients with IR AAA, the proximal mediandiameter was 23.2mm (15mm-36.9mm) with 75% of aUdiameters less than 25.3 mm. The right and left median iliacartery diameter was 12.5 mm (6.6-19.7) and 12.8mm (9.8­17.2) respective1y with 75% of alJ iliac diameters below14.2mm. Median 1ength of proximal infra renallength was29. l (15-48 mm) with all patients having greater than 15mmlength. Median diameter of right and left femora1 arteries were11.4 (8-15.7mm) and 11.0 (6.5-14.7 mm) with 75% offemora1arteries greater than 9.9mm. No significant angulation of theproximal or distallanding sites were noted.

PTA median patency 105 days, p=0.008). Thrill at PEdiSlal

waspredictive of outcome (p=0.039) and even more so when Tand TSP combined were compared to PST and P combined(p=0.026). Similar but less pronounced effects were seen at

PEnUd and PEplIl';m'J"

CONCLUSION: The presence of a thrill or slightly pulsatilethrill at the dis tal (venous) end of a dialysis graft is the bestpredictor of outcome following percutaneous intervention.Physical findings should supplant pressures as an endpointof dialysis access interventions, and serve as an essentialcomponent of quality assurance in such interventions.

ageLenglh ol stay (days)SurvivaJComplications