--.....SIR ''''''''''''l'2£:

Table: % apoptosis of Liver CaAcer CellsDose of SR (mg/kg) % Apoptosis SDo 1.3a 0.11 44.8b 12.85 52.7b,c 1.910 70.7c 21.7Note: Groups identified with the same superscript leller are not significantly different

(P>0.05).

retrospectively. One case was normal. There was no PAproviding information not seen in the DSA. Superselectiveembolization of the identified branch was performed in thesame sitting with DSA (12).

CONCLUSION: PA is not necessary in the evaluation ofextra hepatic perfusion shown in liver perfusion nuclear scans.Positive and negative pump studies will need follow-up byDSA with intention to treat or confIrm the absence of extrahepatic branch that can be treated, respectively. Werecommend percutaneous DSA and embolization of theabnormal branch as the next step, in all cases of extrahepaticperfusion after implantation of arterial chemoinfusion pumps.

The Effect of Benzamide Riboside on a VX2 Model ofLiver Cancer in Rabbits.G. McLennan, Indiana University Medical Center,Indianapolis; IN, USA ·E.K. Cressman..J. Mandar·Z.Dianbo·X. Yonghua 'H. Jayaram

PURPOSE.: Benzamide Riboside (BR) causes apoptosis inmultiple tumor cell lines by inhibiting guanylate biosynthesis.The purpose was to determine the feasibility of using BR asa therapeutic agent for intra-arterial cancer therapy.

MATERIALS AND METHODS: VX2 was injected in the leftlobe of the liver of 14 New Zealand White rabbits & allowedto grow for 19 ± 3 days. The hepatic artery was catheterizedwith a 3 French catheter via right femoral cut-down. Animalswere given one infusion of 0.9% Saline (n=2), I mg/kg (n=4),5 mg/kg (n=4), or 10 mg/kg (n=4) of BR into the hepaticartery. I animal treated with 5mglkg failed to develop tumor.Livers were explanted after 24 hours. Livers were sectionedthrough the tumor and through normal liver. Terminaldeoxynucleotidyl Transferase Mediated dUTP Nick EndLabeling (TUNEL) staining was performed and slides wereimaged on a Zeiss LSM 510 confocal microscope at 40X todetect apoptotic cells. Four random fIelds were obtained fromeach slide and the percentage of apoptoticcells was calculatedby dividing the number of TUNEL positive cells by the totalnumber of cells. Sections of liver not invo"lved with tumorwere obtained in5 animals; 2 that received 1 mg/kg, I at 5mg/kg, and 2 at 10 mg/kg. The effect of treatment was analyzedwith a one-way ANOVA.

RESULTS: The mean tumor apoptosis in treated animals wasgreater than in animals treated with saline (p=0.003) 'and wasgreater with 10mg/kg than with Img/kg (p=0.03). The tabledemonstrates the percentage of apoptotic cells at eachdose ofBR administered. There were no apoptotic cells in normalliver treated with I mglkg & 10 mglkg. The animal that received5 mg/kg demonstrated 10.5% apoptotic cells in the fieldexamined (8/76 cells). In the animal treated with 5mg/kg butdid not grow tumor, only I of76 cells (0.65%) were apoptoticin the area of the injection scar.

CONCLUSION: BR induces apoptosis in VX2 tumor in therabbit model with limited apoptosis in normal liver.

Abstract No. 98

Abstract No. 97

8:12AM

Sunday, April 3, 20058:00 AM - 9:30 AMModerator(s): Shaun Samuels, MD

Bien-Soo Tan, MD

Microbubble Augmented Sonothrombolysis of OccludedDialysis Grafts: Initial Human Experience.W. C. Culp, University ofArkansasfor Medical Sciences, LittleRock. AR, USA ·R.B. McLafferty·R.P. Uflacker'C.H.Danielson-T. Matsunaga·E.C. Unger, et al.

PURPOSE: Transcutaneous ultrasound augmented withmicrobubbles has proved a successful thrombolysis techniquein animal models. The purpose of this study of SonoLysis ™is to demonstrate safety and obtain preliminary measurementsof effIcacy in a Phase IIII human feasibility study ofperflutrenlipid microsphere microbubbles (MRX-815, ImaRxTherapeutics, TUcson, AZ) used with ultrasound for lysis ofthrombosed dialysis grafts.

MATERIALS AND METHODS: This multi-center prospectivestudy used 2 sequential cohorts, both of which had thromboseddialysis grafts treated with intra clot microbubbles (1.4 cc

8:00AM

Place of Service Variation in the Utilization ofHemodialysis Procedures: National Medicare Data, 1997­2002.J.D. Gordon, Mayo Clinic, Rochestel; MN, USA ·S. Misra 'L.Parker·V. Rao

PURPOSE: To determine changes in hemodialysis procedureutilization rates (UR) by place of service and specialty.

MATERIALS AND METHODS: The CMS Physician/SupplierProcedure Master Summary Files containing all Medicare PartB procedures were accessed for the years 1997 to 2002.Thirteen separate CPT-4 codes involving dialysis procedureswere selected. The data were divided by specialty (Radiology,Cardiology, Nephrology, and Surgery). The data were furtherdivided based on procedure location including inpatient,outpatient, office, and ER. Utilization rates (UR) werecalculated per 100,000 Medicare beneficiaries.

RESULTS: The total number of dialysis procedures increasedfrom 625,545 in 1997 to 1,113,984 in 2002. In 2002, 57.8%were performed on an outpatient basis, 31.6% were performedon an inpatient basis, 7.2% were performed in an office setting,0.67% were performed in the ER, and 2.7% were performedin all other locations.

The UR of outpatient dialysis procedures increased 73.3%,from 1018 to 1764 in 5 years. Radiology experienced anincrease of78.3% in the UR of outpatient dialysis procedures,Nephrology 374%, Cardiology 150%, and Surgery 53.2%,respectively. The UR of inpatient dialysis proceduresincreased 21.4%, from 794 to 964 in 5 years. Radiologyexperienced an increase of 51.9%, Nephrology 88.5%,Cardiology 66.7%, and Surgery 1.6%, respectively.

CONCLUSION: Other specialties, especially Nephrology andCardiology are performing more endovascular procedures ondialysis patients. The trend is most evident in the increasingnumber of outpatient procedures.

Scientific Session 17Dialysis Access

Abstract No. 96FEATUREDABSTRACT

Commentator: .Jeff H. Geschwind, MD

9:00AM

S36

diluted to 6 cc, injected over 30 minutes) and 30 minutes oftranscutaneous ultrasound. The first cohort received 4 mg oftissue plasminogen activator (tPA) in the thrombus and thesecond did not. Variable amounts of ultrasound from 0.6 WIcm2 continuous wave to 10 W/cm2 at 10% duty cycle wereemployed in both cohorts. Angiographic flow was scored ona modified thrombolysis in myocardial infarction flow scaleof 0 to 3, and lumen filling was scored on a 0 to 4 scale in eachthird of the graft.

RESULTS: Twenty two patients completed the protocol with13 receiving all the scheduled angiograms. The 22 reported apain free experience with no serious adverse events. Nonewithdrew from the procedure. Patients with completeangiography treated both with and without tPA, all showedangiographic improvement in luminal filling. In 7 performedwith tPA, mean luminal filling rose from 0.33 to 2.62 andmean flow rose from 0.12 to 1.38. In 6 without tPA, luminalfilling rose from 0.44 to 2.0 and flow from 0 to 1.22. Finallumen filling of tPA and no tPA groups was similar, but thissmall feasibility study was not powered to demonstratestatistical evidence of comparable efficacy. Three of the totaldid not require venous stenosis angioplasty. Ten did not requireremoval of the arterial plug.

CONCLUSION: Treatment resulted in improved luminal fillingin both tPA and non tPA groups without sign of serious adverseevent. The phase UII human trial shows dialysis graftsonothrombolysis to be a potentially safe means of therapywith preliminary efficacy both with and without tPA. Furthertrials are warranted.

Transrenal Arteriovenous Dialysis Graft Creation Usinga Simplified Technique: Experimental Study in Animals.M.J. Wallace, The University ofTexas M.D. Anderson CancerCenter, Houston, TX, USA'P Tinkey-K. AhrarK.C. Wright

PURPOSE: To further investigate the experimental creationofa percutaneous arteriovenous (AV) graft via the renal vesselsusing a simplified technique and to report its safety,complications and I-month patency.

MATERIALS AND METHODS: Transrenal AV grafts werecreated from the renal artery (RA) to the renal vein (RV) in 6swine. Percutaneous RA and RV access was accomplishedusing a previously described combined transfemoral/percutaneous snare technique to accomplish through-and­through control. Both flank accesses were upsized toaccommodate sheaths for SG deployment. A 7mm x 15 cmstent-graft (SG) was deployed from the RV-lVC confluenceout the flank and a 6 mm x15 cm SG ,was deployed from theRA origin out the flank. The venous limb was dilated to 6 mmand the arterial limb to 5 mm. The external portion of thearterial limb was telescoped into the venous limb and bondedtogether with cyanoacrylate glue to form one continuous loop.A subcutaneous pocket was then fashioned and the loop wasinserted below the skin. Procedural Clopidogrel (l Omglkg IVbolus) was administered continued at 75 mg per day. Theprocedure time (femoral access to subcutaneous pocketclosure) was recorded. Technical success was defined as thesuccessful creation of an AV graft with rapid arterial-venousshunting on completion arteriography. Shunt patency wasassessed by auscultation and angiography. All animalsunderwent a complete necropsy.

RESULTS: AV graft creation was technically successful in all6 animals with rapid AV shunting documented on completionangiography. The average procedure time was 84 minutes(range 70-130 minutes). No technical procedure related

CONCLUSION: Transrenal AV graft creation using thesimplified technique can be performed safely in the animalmodel. Delayed complications involving graft infection andocclusion must be overcome prior to introduction into theclinical setting.

S37

Abstract No. 1008:36AM

complications occurred, but graft infection occurred in 2animals. At 4 week follow-up 4 of 6 shunts were occluded, asevidenced by absence of a bruit by auscultation andconfumation ofocclusion by angiography. Moderate (50-75%)diffuse in-stent stenosis was present in 2 animals. Histologicassessment of in-stent occlusions is pending.

The Effects of Technique in PharmacomechanicalThrombolysis in Arteriovenous Grafts.J.P Eaton, TripLer Army Medical Center, TripLer AMC, HI,USA-J. T. Watabe 'R. C. Yoon

PURPOSE: To determine the effectiveness of various methodsof pharmacomechanical thrombolysis currently employed inthe treatment of hemodialysis graft (HD) occlusion.

MATERIALS AND METHODS: We reviewed ourhemodialysis access database for patients who underwentpharmacomechanical thrombolysis of occluded HD grafts.We compared three different methods of pharmacomechanicalthrombolysis. These include the (1) use of simple aspirationwith or without intrathrombus TPA, (2) the Angiojet rheolyticcatheter, and (3) the Trerotola thrombectomy device. Thefactors evaluated included: clinical outcomes, room andprocedural times, and procedural costs.

RESULTS: The most common procedure performed to clearthrombosed HD grafts was the use of simple aspiration. 124of these procedures were performed in an 18 month periodfrom 7/01-12/02. These were compared to 10 procedureswhich utilized the rheolytic catheter and 17 procedures whichutilized the thrombectomy device. Clinical outcomes werenot significantly different among the different procedures withfailure rates of 6% for the simple aspiration technique, 10%for the rheolytic catheter, and 18% for the thrombectomydevice. When procedural variables were compared, the durationof time the patient was in the angiography suite wassignificantly longer when a rheolytic catheter (156±28 min)or a thrombectomy device (l32±64 min) was utilized ascompared to simple aspiration (88±28 min). Procedural timewas significantly longer with the use of the rheolytic cathetercompared to simple aspiration (131±14 min vs 47±24 min,p<O.OOI). Fluoroscopy time was also significantly longer withthe use of the rheolytic catheter compared to simple aspiration(17.4±15.2 min vs 5.5±3.5 min, p<0.02). There was nodifference in the overall radiation exposure to the patient amongthe three methods. Finally, the cost of supplies as an overallpercentage of the procedure was 21 % when a rheolytic catheteror thrombectomy device was utilized but decreased to 13%when simple aspiration was employed.

CONCLUSION: A simplified aspiration technique forthrombus removal is as effective as more expensive methodsof pharmocomechanical thrombolysis for the treatment ofoccluded HD grafts.

Abstract No. 998:24AM

Who Is Performing Hemodialysis Procedures? NationalMedicare Data, 1997·2002.J.D. Gordon, Mayo Clinic, Rochester. MN, USA ·S. Misra·L.Parker-V. Rao

PURPOSE: To examine trends in hemodialysis procedureutilization rates (UR) by specialty from 1997 to 2002.

MATERIALS AND METHODS: The CMS Physician/SupplierProcedure Master Summary Files containing all Medicare PartB procedures were accessed for the years 1997 to 2002.'Thirteen separate CPT-4 codes involving endovascular dialysisprocedures were selected. The data were divided by specialty(Radiology, Cardiology, Nephrology, and Surgery). Utilizationrates (UR) were calculated per 100,000 Medicare beneficiaries.

RESULTS: From 1997 to 2002, the UR of dialysis proceduresacross all specialties increased from 1928 to 3052, a growth of58.3 %. The UR for Radiologists increased 76.7%, from 935in 1997 to 1653 in 2002. Nephrologists experienced the greatest

Impact of an Access Coordinator on a HemodialysisProgram.S.S. Berman, Southern Arizona Vascular Institute, Tucson,AZ, USA-A. Altamirano'R. C. Quick·A. T. Gentile

PURPOSE: This study was undertaken to determine the effectthat a dialysis access coordinator has on the type and quantityof access procedures performed in an access program andwhether a coordinator is a budget neutral provider for thepractice.

MATERIALS AND METHODS: The number of new accessprocedures performed over a 48-month period were dividedinto two groups based upon the presence (PAgroup) or absence(NPA group) of the access coordinator. In the PA group aphysician's assistant functioned as a full-time dialysis accesscoordinator and was responsible for evaluating new dialysispatients, including the use of venous mapping; coordinatingthe surveillance program; maintaining an access database; andplacing acute dialysis catheters for emergent access.Comparisons between the groups were made using Chi squareanalysis. The reimbursement for the coordinator's serviceswas recorded along with the expenses relative to thecoordinator's employment.

RESULTS: During the period of review, 1214 access procedureswere performed. In the NPA group, 369 new access procedureswere performed of which 195 were autogenous and 174 wereprosthetic grafts. In the PA group, 454 new access procedureswere performed comprising 262 autogenous and 191 prostheticgrafts. The incidence of autogenous accesses increased from52.8% in the NPA group to 57.5% in the PA group (p=0.18).In the NPA group, 132 revisions were performed of whichonly 11 (8%) were balloon angioplasties for failing but patentaccesses. In the PA group, 259 revisions were performed ofwhich 97 (37%) were percutaneous revisions of patent butfailing accesses. The incidence of elective, and largelypercutaneous revision of failing accesses increased significantlywith the availability of an access coordinator (p<O.OOl).Reimbursement to the practice for the coordinator's servicesexceeded the expense of the position by a factor of 1.2.

CONCLUSION: An access coordinator has improved ourability to meet K-DOQI guidelines, has increased the numberof percutaneous interventions on patent access sites, and hasreduced the percentage of clotted access sites. The cost of afull-time coordinator can be tangibly recovered throughreimbursable services.

Scientific Session 19Oncologic Interventions:Percutaneous Ablation

Abstract No. 1032:15PM

Sunday, April 3, 20052:15 PM - 4:00 PMModerator(s): Stephen T. Kee, MD

S. Nanum Goldberg, MD

Percutaneous Cryotherapy of the Thorax: TechnicalAdvances and Feasibility for Complex Patients.P.L. Littrup, Karmanos Cancer Institute, Detroit, MI, USA 'A.Abraham'. Sam'H.L. Monte

PURPOSE: To report our U.S. experience of percutaneouscryotherapy of the thorax (PCT) in non-operative andmetastatic patients.

MATERIALS AND METHODS: Seventeen patients underwent21 CT-guided PCfs for masses of various histologies usingprimarily the CT-compatible (i.e., L-shaped handle) 2.4mmcryoprobes. Seventeen masses were unresponsive metastases,receiving PCT to potentially control local morbidity. Fourmasses were primary lung tumors in non-operative patients.The locations of the masses were as follows: 9 within lungparenchyma, 3 within the chest wall, 5 involving hilar structuresand 4 abutting the mediastinum.

RESULTS: All patients underwent PCT using local anesthesiawith minimal or no sedation. Only 2 were not dischargedwithin six hours after the procedure, unrelated to treatmentside effects. No patients developed pneumothorax requiringintervention and 2 patients developed an effusion treated bya single drainage. Ice formation was identified on Cf as reducedHounsfield units within the soft tissue masses. Greaterflexibility of cryoprobe placement with the newer L-shapedprobes (i.e., allowing direct visualization during the freezecycles), appeared to remedy the incomplete ice coverage oflarger and/or central masses previously noted. Avascular,necrotic cavitation larger than the original mass developed in

Sunday, April 3, 20058:00 AM - 9:30 AMModerator(s): John A. Kaufman, MD

TBD

growth (580%), with an increase in the UR from 21 to 142.The UR for Cardiologists increased 93.1 %, from 36 in 1997to 70 in 2002. Surgeons showed the least growth (24.8%),with an increase in the UR from 809 to 1010. The DR forMulti-Specialty groups decreased 0.3% from 1997-2002. TheUR for all other specialties increased 95.6% from 53 in 1997to 103 in 2002. The UR for hemodialysis catheter proceduresincreased the most for Radiologists (327.5%), followed byNephrologists (211 %), Surgeons (30.5%), and Cardiologists(0%), respectively. Angioplasty procedures increased the mostfor Nephrologists (728%), followed by Surgeons (211 %),Cardiologists (83.3%), and Radiologists (58.4%), respectively.

CONCLUSION: Hemodialysis procedures performed byRadiologists continue to grow with hemodialysis catheter workrepresenting the largest increase. Furthermore, the UR forSurgery, Cardiology, and Nephrology have increased withNephrology showing the most growth overall (580%).

Scientific Session 18Late Breaking Abstracts

Abstract No. 102

Abstract No. 101

9:00AM

8:48AM

538