ischemia, were not observed. Twelve patients are aliveand doing well (mean follow-up term: 7.5 months).

CONCLUSIONS: Although further investigation is manda­tory, endovascular stent-grafting for the treatment ofaortic dissections is feasible, safe, and may be effective inhighly selected patients.

Monday, March 22, 19991:00 pm-2:30 pm

MATERIALS AND METHODS: Transcatheter closure ofmembranous VSDs was attempted in 12 Yucatan mini­pigs with natural membranous VSDs. The prosthesis isconstructed from 0.004-in Nitinol wires with two reten­tion buttons and a connecting waist. Two kinds of pros­theses were used in this study: Concentric retentionbuttons (n = 3, 3-mm round flange) and eccentric deSign(n = 9, 2-mm flange toward the aorta and 5-7-mm flangetoward the muscular septum). A 6 Fr or 7 Fr introducingsheath was used to deliver the device.

PURPOSE: To evaluate a new prosthesis for closure ofmembranous VSD in a natural swine model.

Percutaneous Laser Lumbar Disk DecompressionVersus Automated Percutaneous LumbarDiskectomy: A Comparative StudyGaojun Teng, MD, Manjing, China. Shicheng He,

MD. Wen Fang, MD. Jinite Guo, MD

Transcatheter Closure of MembranousVentricular Septal Defects with a New NitinolProsthesisXia0ping Gu, MD, Minneapolis, MN. Young-MinHan, MD • Myra C. Urness, BS. john 1. Bass, MD •

James Berry, RDMS. Kurt Amplatz, MD

RESULTS: Within 8.5 months (range, 6.0-14 months) offollow-up care, 84% of the patients in the group treatedwith PLDD had a good or fair response compared with82% in the control group (P > 0.05). There were nocomplications in either the PLDD group or the APLDgroup.

CONCLUSIONS: This study suggests that PLDD with asemiconductor laser is effective and safe in patients withIwnbar herniation and is comparable to APLD. Furtherinvestigations are needed, however, to clarify the long­term results.

Abstract No. 631:30 pm

PURPOSE: Independently by their etiology, the introduc­tion of Botulinic Toxin Type A allowed new therapeuticapproaches in pathologic situations like distrectual dys­tonia and motor dysfunction like spasticity. The toxin'sinoculation can be performed easily in superficial mus­cles; when dealing with deep muscles, however, thetreatment usually is performed by EMG guide. The aimof our study was to evaluate the pOSSibility of CT guid­ance in the treatment of nonpalpable muscle involve­ment by distrectual dystonia.

RESULTS: Successful implantation of the device wasachieved in all animals. One animal was euthanized 2days after placement because of coma. The aneurysm ofmembranous septum increased significantly in size intwo of the three animals using the concentric device(re-opening of the VSD at 1 month and 3 month fol­lOW-Up evaluation occurred in one animal), but in noneof the cases using the eccentric device. Aortic regurgita­tion was present in two of the three animals using theconcentric device, and in only one of nine animals usingthe eccentric device. Three animals had a trace to mod­erate tricuspid regurgitation. Complete closure rate ofVSD was 58.3% (7/12) immediately after placement,100% (11/11) at 1 week, 90.9% (10/11) at 1 month and 3months, and 100% (4/4) at 6 months. Pathologic exam­ination showed the devices to be covered by smoothglistening neoendothelium.

CT-Guided Injection of Botulinic Toxin forPercutaneous Therapy of Pyriformis MuscleSyndromeEzio Fanucci, MD, Roma, Italy. C. Iani, MD.Viviana Varruccio, MD. Giovanni Simonetti, MD

CONCLUSIONS: Effective and permanent occlusion ofmembranous ventricular septal defect is feasible withthis new prosthesis. The eccentric device can effectivelyavoid an enlargement of the aneurysm in membranousseptum, eliminating distortion of the aortic annulus thatresults in aortic insufficiency. Tricuspid regurgitationwas found in some cases resulting from over-length ofthe device waist.

MATER.IALS AND MEWODS: We evaluated 30 patientssuffering from pyriformis muscle syndrome. Patients lieon CT-support in the prone pOSition. A few scans wereacqUired to localize the pyriformis muscle. Toxin inoc-

Abstract No. 62

Abstract No. 61

1:15 pm

PURPOSE: To evaluate percutaneous laser decompres­sion (PLDD) compared with automated percutaneouslumbar diskectomy (APLD).

MATER.IALS AND MEWODS: PLDD using a semiconduc­tor Diode laser (Diomed LTD, 810 nm, 15w, 1.0 secondpulse, 2-4 second interval, 1,300 J) or APLD (50 patients,control group) using a Teng's device was performed in50 patients with lumbar herniation. The patients werefollowed up with physical examinations and/or CT scanat 3-month intervals. The clinical responses were judgedwith MacNab's criteria.

Scientific Session 11

New Techniques 1Moderator: Charles P. Semba, MD

1:00 pm

230

ulation always is preceded by an intramuscular injectionof 5 cc of anesthetic (lidocaine) using a 20-gauge needleto check treatment effectiveness. Toxin was introducedin a quantity of 100 UI inside each pyriformis muscle.

RESULTS: In 26 cases, a relief of symptoms was obtained

after 5-7 days; in the other four patients, the relief wasinsufficient probably due to a plurisymtomatologic syn­

drome.

2:00 pm Abstract No. 65

Diagnostic Yield of Magnetic Resonance-GuidedLiver Biopsies Compared with cr and US GuidedLiver BiopsiesAndrew j. Schmidt, MD, Stanford, CA • Stephen TKee, MD • Daniel Y. Sze, MD, PhD. Mahmood K.Razavi, MD. Charles P. Semba, MD. Michael D.

Dake, MD

CONCLUSION Our preliminary experience shows thatBotox-CT treatment is a suitable therapy for pyriformismuscle syndrome. It allows a remarkable accuracy (dur­ing inoculation) and is better accepted by patients thanEMG guide. No postprocedure complications occurred.

CONCLUSIONS: Decrease in procedure times, radiationdoses, number of hepatic punctures, and fluoroscopyduration indicates superiority of C-arm supported CT­fluoroscopy over conventional fluoroscopic approaches

in placement of percutaneous biliary drainages. Espe­cially because fewer hepatic punctures are required,procedure safety may be increased with the combinedmethod.

Combined C-Arm Supported cr Fluoroscopy inPlacement of Percutaneous Biliary DrainagesJens j. Froelich, MD, Marburg, Germany. Joachim H.

Wagnel~ MD. Klaus j. Klose, MD, PhD

PURPOSE: Prospective evaluation of combined CT-fluo­roscopy with C-arm support in placement of percutane­ous biliary drainages (PBD) and comparison with con­

ventional fluoroscopic approach.

231

MA TERlALS AND MEmODS: A high output chylothoraxdeveloped in six patients (5M,lF) after esophageal (n =

3), lung (n = 1), or aortic (n = 1) surgery and a vehicularaccident (n = 1). After pedal lymphography, the CC waspunctured under fluoroscopy via a percutaneous subxy-

2:15 pm Abstract No. 66

Evaluation and Management of TraumaticChylothorax by Percutaneous Catheterization ofthe Cisterna ChyliConstantin Cope, MD, Philadelphia, PA

PURPOSE: To identify and embolize thoracic duet fistu­lae by percutaneous transabdominal catheterization ofthe cisterna chyli (CC) and the thoracic duct (TD).

CONCLUSIONS: MRI guided biopsy of liver lesions usinga 0.5 Tesla open-configuration magnet is safe and accu­rate when compared with CT and US. No statisticalsignificance was observed when comparing MR with CTand US diagnostic yield. However, a number of MRprocedures were performed of lesions in the hepaticdome, and of low contrast images, which would nor­mally be difficult to perform safely using CT or US.

MATERIALS AND MElliODS: MR, CT, and us liver biop­sies from September 1996 through September 1998 werecompared. Fifty-seven patients (23 men, 34 women,mean age 62 years) had MR biopsy of liver lesions. Thirtypatients (19 men and 11 women, mean age 59 years) hadCT biopsy. Eighteen patients (8 men and 10 women,mean age 50 years) had US biopsy. MR procedures wereperformed in an open-configuration GE 0.5 Tesla SignaSP MRI unit. Lesion localization utilized standard T1 andT2 sequences, while biopsies were performed with aMPSPGR sequence (TRITE = 130/2.I). A coaxial systemwith an I8-gauge nickel-titanium stabilizing needle anda 21-gauge aspiration needle was used to obtain thesamples. CT and US procedures used a 19-9auge stabi­liZing needle and a 21-gauge aspiration or a 20-gaugecore biopsy needle. A cytotechnologist was present todetermine the adequacy of samples.

PURPOSE: To compare diagnostic yield and complica­

tion rates of MRI guided versus CT and us gUided liver

biopsies.

RESULTS: MR had a diagnostic yield of 68%. CT and UShad a 67% and 61% diagnostic yield respectively. Noserious complications were reported for MR or US pro­cedures. Two CT biopsies had post-procedural hemor­rhage. One required surgical exploration and died.

Abstract No. 641:45 pm

RESULTS: Compared with patients treated with conven­tional fluoroscopy, combined C-arm supported CT-fluo­roscopy was associated with a significant decrease ofprocedure times, radiation doses, number of hepaticpunctures, and fluoroscopy duration (P < 0.05, t Test).Although in conventional procedures a mean of 4.8 ::'::1.8 hepatic punctures and a fluoroscopy time of 21.4 ::'::3.3 minutes was necessary, application of the combinedmethod resulted in 1.6 ::':: 0.9 hepatic punctures and in afluoroscopy time of 4.1 ::':: 2.1 minutes for PBD place­ment.

MATERIALS AND MElliODS: Ten patients with biliaryobstructions receiving PBD procedures have prospec­tively been treated either with a conventional fluoro­

scopic approach or with combined C-arm supportedCT-fluoroscopy. With the combined method, a selectedbile duct is initially punctured using CT-fluoroscopy, andconsequently the patient couch is moved out of the

Gantry to be positioned under a C-arm fluoroscopy unitfor introduction of guidewires and drainages. Proceduretimes, radiation doses, number of hepatic punctures, andfluoroscopy duration were analyzed and compared be­tween both groups.

fore and afLer treatment. Cardiopulmonary autopsywas performed to assess the procedure's safelY.

RESULTS: Four pigs died during embolization.111fombectomy could be perform d in eight pigs. TheHydrolyser could be manipulated only in central pul­monary arteries and could a pirate some c ntral em­bQli in three pigs. Most of the emboli were peripher­ally located, however, and could not be reached withthe cath ter. There was no significant hemodynamic,gasometri , or angiographic improvement immedi­ately after treatment. The procedure al'o induced an'increase in free hemoglobin blood level, most likelyfrom hemoly is indu ed by the cath ter' vonex ef­fe l. Autop y in 12 pigs revealed minor endothelialinjuries. Most of dlese injurie were adherent endo­cardial thrombus in the right ventricular outflow tract.On av rage, two ndothelial injuries per pig wereobserved in both nontl'eated (n = 4) and Hydrolyser­treated groups (n = 8).

CON, ZUSIONS: The Hydroly er thrombectomy cath­eter can be promptly po itioned and ea ily steer dincentral pulmonary arteri s. There were no importantinjuries to the right hean or pulmomuy arteries. How­ever, the l1yd.rolyser did not remove peripheral PE.Central. emboli were seen in four pigs and were onlypartially removed in three animals.

phoid approach with a skinny needle through a stiffen­ing cannula; the TD was catheterized with a 3F catheterover a microguidewire. The proximal TD was occludedwith microcoils when a TD fistula was opacified.

RESULTS: The CC was successfully punctured in fourpatients and the TD catheterized in three patients; twoTD fistulas were embolized with cure. No leakage sitewas observed in the other two patients, and their chylo­thora.,'{ subsided soon thereafter. In the remaining twopatients (postaortic surgery and vehicular trauma) theCC was replaced by lymph collaterals too small to bepunctured. There was no procedural morbidity in anysubject.

CONCLUSIONS: Percutaneous CC and TD for possibleembolization is an accurate, safe, and efficacious tech­nique for evaluating and managing chylothorax. It cansave patients from having a second thoracotomy for TDligation.

Monday, March 22, 19991:00 pm-2:30 pm

Scientific Session 12ThrombectomyModerators: Michael C. Soulen, MD

Jim A. Reekers, MD1:15 pm Abstract No. 68

FEATURED ABSTRACTCommentator: Melhem J. A. Sharafuddin, MD

Percutaneous Removal of Pulmonary ArteryEmboli in Pigs with Hydrolyser CatheterLite lacou.rsiere. MD, FRCP(C), Ste-Foy, Canada.Steven Millward, MBChB, FRCR. FRGP(C) • johnVeinot, lll!D, FRCP(C) • Marino labinaz, MDFRCP(C)

1:00 pm Abstract No. 67I FEATURED ABSTRACT

Commentator: Melhem J. A. Sharafuddin, MD

Evaluation of a Modifted Arrow-TrerotolaPercutaneous Tbrombolytic Device forTreatment of Acute Pulmonary Embolus in aCanine Model

. Daniel B. Brown, MD, Hershey, PA. jobn F.Cardella, MD. R01Wld P. Wilson, VMD, M. •

Harjit ,ingh, MD. Petm" . Waybill, l\tlD

232

PURPOSE: To evaluate the efficacy and tl1e safety ofth Hydroly er catheter for percutaneous treatment ofmas ive pulmonary emboli m (PE) in pigs.

MATERIALS AND METHODS: Twelve pigs weighing55-89 kg w re used in this study. Radioopaque 9-cmclots were first produced by mixing pig' blood withiodine cOfltrast agent in vacutainer . Tb e cI t wereinjected via rh jugular vein until obtaining central PE(main and proximal lobar artertes) wirh significantsystemic and pulmonary hemodynamic modifica­r.ions; however, injected dots tended to fragment andlocate peripherfl,Uy in segmental alteries. From a fem­oral approach, the 7 Fr HydrolyseI' thrombectomycatheter was used over a O.025-in h guidewire toremQ pulmonary emboli. Hemodynamic, ga omet­ric, and angiogrilphic monitoring was performed be-

PURPOSE: Massive pulmonary embolus (PE) i oftenrapidly fatal. Smgical thrombectomy has a mortalityfate as high as 74%. Multiple percutaneous methodshave been tested with linuted sllccess. The pnrposeof th.is tud wa to evaJuaLe the Arrow-TrerotolaPercutaneou Thrombolytic Devi e (PTD) for abilityto dear pulmonary embolus and for its effect on

. normal pulmonary vasculature. These were t t d in

a canine model.

l'vIA1T:KlA AND METHODS: Iatrogenic unilateralmassive PE's were created in nine canines. These PE'sdlen were treated with the PTD, and the device alsowas activated. in the normal pulmonary artery. Imme­diately after treatment, six animals were sacrificed.Three animal' were recovered and restudied in ]month to valuat for pulmonary hypertension, te-