S88 CONCLUSION: Primary stenting for renal artery stenosis secondary to atherosclerotic disease is effective in improving blood pressure. Poster No. 253 Ultrasonic Ablation in Atherosclerosis Obliterans. WA. Lin, The Provincial Hospital ofHei Long luang, Harbin, China· L.L. Meng Xin • e.G. lun PURPOSE: To evaluate the clinical efficiency of intravascular ultrasonic ablation in patients with atherosclerosis obliterans. MATERIALS AND METHODS: 56 patients of atherosclerotic plaques with total occlusion in peripheral arteries received intravascular ultrasonic ablation. Through percutaneous approach or surgical approach ultrasonic ablation catheter was inserted into occluded arterial segments. The time of ultrasonic ablation was 12 minutes. RESULTS: Ultrasonic transmitter easily created a channel within the occlusive material and achieved sucessful recanalization in 54 patients. The immediate angiogram of the treated arteries showed an average lumen patency of 80%. The blood flow of treated arteries was improved. A8 week follow-up showed reocclusions in 2 patients one year follow- up showed reocclusion inJ patients. CONCLUSION: The results suggest that intravascular ultrasonic ablation is an effective therapeutic modality for patients with atherosclesosis obliterans. The advantage of the ultrasonic ablation was the creation of a channel within the total occlusion. Ultrasonic ablation may be a new approach for recanalization of totally occluded peripheral arteries. Ang iog ra phy/Contrast Agents Poster No. 254 The Change of the Renal Function after Injection of Contrast Medium in Acute Renal Failure Rats. Y Han, Chonbuk National University Hospital, Korea· S. Kim· e. Kim PURPOSE: To evaluate the safety and effectiveness of renal function after injection of conb'ast medium in acute renal failure rats. MATERIALS AND METHODS: 110 male rats weighing 250- 300 g were used for ischemic renal injury. The abdominal cavity was opened via a midline incision uder 0.1 ccll 00 mg of Ketamin and Xylazine mixtures (9: I ratio) in anesthesia. Both renal pedicles were exposed and cleaned by blunt dissection. Microvascular clamp's were placed on both renal arteries and veins to complete block renal blood flow. After 45 minutes, the clamps were removed and blood flow returned back to the kidneys. The acute renal failure rats divided into two groups: one is CT contrast and the other is MR contrast. Each CT and MR groups divided into three groups: Jow dose (0.5 cclkg, 0.2 mllkg), standard (2 cc/kg. 0.8 mJlkg) and high (8 cclkg, 3.2 mll kg). The blood sampling was performcd before ARF, 48 hours after ARF, and 48 hours after injection of contrast medium. Each group performed image of both kidney by CT or MR!. Each group was compared with 48 hours creatinine level after injcction of contrast medium by one-way ANOYA test. RESULTS: The ARF was perfonned succcssfully in 80 ratsl IJ0 rats (ARF was defined two fold increase of creatinine levcl bctween pre ARF and 48 hours later ARF). Each group was in low dose (n=10), standard dose (n=l 0) and high dosc (n=IO) of CT contrast medium injection, and in low dose (n= I0), standard dose (n=10) and high dose (n=10) of MR contrast medium injection. In the CT groups, the CT scans showed good image in the standard and high dosc of injection. In the MRI groups, the MR scans showed good image in the standard and high dose of injection. There was no significantly different creatinine level between CT and MR groups (P=O. 116). There was no significantdifference creatinine level between different doses of CT and MR contrast medium. CONCLUSION: The CT contrast medium doesn't aggravate of the ARF compared to MR contrast medium in acute renal failure rats. The standard and high dose ofCTand MR contrast medium shows good image compared to low dose of contrast medium. Poster No. 255 Plastic Bag Delivery System for CO z DSA Angiography. 1. Hawkins, Radiology, Shands at the University of Florida, Gainesville, FL, USA· S. Klioze .1. Caridi· 1. Handel PURPOSE: CO 2 as an angiographic contrast agent has been used in our institution since 1971 in over 2,000 patients. CO, is very difficult to deliver because of its Although we have developed an extremely safe dedicated CO z injector, which is not yet FDA approved, homemade hand delivery systems are potentially very dangerous, causing delivery of excessive volumes, air contamination, and explosive delivery. We have recently modified a plastic bag delivery system which has proven to be safe, easily learned and provides diagnostic images in the majority of the studies. MATERIALS AND METHODS: The delivery system consists of a 1500 cc plastic bag with a gas O-ring fitting. The bag is filled via a submicron filter with 99.99% CO 2 from a disposable cylinder individually tested for purity. The bag is connected to a closed delivery system with multiple check valves to eliminate air contamination and stopcock manipulation. Since the bag is filled at atmospheric pressure, the delivery syringe will contain only the amount of CO 2 that is aspirated. To prevent explosive delivery, the catheter is cleared ofliquid by forcefully injecting 5 cc of COr We retrospectively examined the charts of the first 325 patients who underwent a variety of angiographic and interventional procedures: aortograms and runoffangiograrns, iliac and renal angioplasty and stents, venous intervention and TIPS. Because of possible neurotoxicity, CO z was not used arterially above the diaphragm. RESULTS: CO 2 runoff studies, including imaging the feet, were considered diagnostic with CO z alone in 88% and CO z plus a small amount of iodinated contrast in 97%. The other CO z studies, including 20 PTAs, 30 stents, 10 embolizations and 50 TIPS, were comparable to iodinated contrast. CO, was of particular importance for renal angioplasties and stent placement, since the low viscosity CO z can be injected between the stent catheter and guidewire, always visualizing the aorto- renal junction, and improving the accuracy of stent placement. No significant increase in renal failure occurred. CONCLUSION: The plastic bag permits easy, safe, controlled delivery ofCO z ' without significant increase in renal failure, pain or intestinal ischemia when delivered in small volumes.
Transcript
S88
CONCLUSION: Primary stenting for renal artery stenosissecondary to atherosclerotic disease is effective in improvingblood pressure.
Poster No. 253
Ultrasonic Ablation in Atherosclerosis Obliterans.WA. Lin, The Provincial Hospital ofHei Long luang,Harbin, China· L.L. Meng Xin • e.G. lun
PURPOSE: To evaluate the clinical efficiency ofintravascularultrasonic ablation in patients with atherosclerosis obliterans.
MATERIALS AND METHODS: 56 patients ofatheroscleroticplaques with total occlusion in peripheral arteries receivedintravascular ultrasonic ablation. Through percutaneousapproach or surgical approach ultrasonic ablation catheterwas inserted into occluded arterial segments. The time ofultrasonic ablation was 4~ 12 minutes.
RESULTS: Ultrasonic transmitter easily created a channelwithin the occlusive material and achieved sucessfulrecanalization in 54 patients. The immediate angiogram of thetreated arteries showed an average lumen patency of 80%.The blood flow of treated arteries was improved. A 8 weekfollow-up showed reocclusions in 2 patients one year followup showed reocclusion inJ patients.
CONCLUSION: The results suggest that intravascularultrasonic ablation is an effective therapeutic modality forpatients with atherosclesosis obliterans. The advantage ofthe ultrasonic ablation was the creation of a channel withinthe total occlusion. Ultrasonic ablation may be a new approachfor recanalization of totally occluded peripheral arteries.
Ang iogra phy/Contrast Agents
Poster No. 254
The Change of the Renal Function after Injection ofContrast Medium in Acute Renal Failure Rats.Y Han, Chonbuk National University Hospital, Korea· S.Kim· e. Kim
PURPOSE: To evaluate the safety and effectiveness of renalfunction after injection ofconb'ast medium in acute renal failurerats.
MATERIALS AND METHODS: 110 male rats weighing 250300 g were used for ischemic renal injury. The abdominalcavity was opened via a midline incision uder 0.1 ccll 00 mg ofKetamin and Xylazine mixtures (9: I ratio) in anesthesia. Bothrenal pedicles were exposed and cleaned by blunt dissection.Microvascular clamp's were placed on both renal arteries andveins to complete block renal blood flow. After 45 minutes,the clamps were removed and blood flow returned back to thekidneys. The acute renal failure rats divided into two groups:one is CT contrast and the other is MR contrast. Each CT andMR groups divided into three groups: Jow dose (0.5 cclkg, 0.2mllkg), standard (2 cc/kg. 0.8 mJlkg) and high (8 cclkg, 3.2 mllkg). The blood sampling was performcd before ARF, 48 hoursafter ARF, and 48 hours after injection of contrast medium.Each group performed image of both kidney by CT or MR!.Each group was compared with 48 hours creatinine level afterinjcction of contrast medium by one-way ANOYA test.
RESULTS: The ARF was perfonned succcssfully in 80 ratslI J0 rats (ARF was defined two fold increase of creatininelevcl bctween pre ARF and 48 hours later ARF). Each groupwas in low dose (n= 10), standard dose (n=l 0) and high dosc
(n=IO) of CT contrast medium injection, and in low dose(n= I0), standard dose (n= 10) and high dose (n= 10) of MRcontrast medium injection. In the CT groups, the CT scansshowed good image in the standard and high dosc ofinjection.In the MRI groups, the MR scans showed good image in thestandard and high dose ofinjection. There was no significantlydifferent creatinine level between CT and MR groups(P=O. 116). There was no significant difference creatinine levelbetween different doses of CT and MR contrast medium.
CONCLUSION: The CT contrast medium doesn't aggravateof the ARF compared to MR contrast medium in acute renalfailure rats. The standard and high dose ofCTand MR contrastmedium shows good image compared to low dose ofcontrastmedium.
Poster No. 255
Plastic Bag Delivery System for COz DSA Angiography.1. Hawkins, Radiology, Shands at the University ofFlorida,Gainesville, FL, USA· S. Klioze .1. Caridi· 1. Handel
PURPOSE: CO2 as an angiographic contrast agent has beenused in our institution since 1971 in over 2,000 patients. CO,is very difficult to deliver because of its compressibility~
Although we have developed an extremely safe dedicated COzinjector, which is not yet FDA approved, homemade handdelivery systems are potentially very dangerous, causingdelivery ofexcessive volumes, air contamination, and explosivedelivery. We have recently modified a plastic bag deliverysystem which has proven to be safe, easily learned andprovides diagnostic images in the majority of the studies.
MATERIALS AND METHODS: The delivery system consistsof a 1500 cc plastic bag with a gas O-ring fitting. The bag isfilled via a submicron filter with 99.99% CO
2from a disposable
cylinder individually tested for purity. The bag is connectedto a closed delivery system with multiple check valves toeliminate air contamination and stopcock manipulation. Sincethe bag is filled at atmospheric pressure, the delivery syringewill contain only the amount of CO
2that is aspirated. To
prevent explosive delivery, the catheter is cleared ofliquid byforcefully injecting 5 cc ofCOr We retrospectively examinedthe charts of the first 325 patients who underwent a varietyofangiographic and interventional procedures: aortograms andrunoffangiograrns, iliac and renal angioplasty and stents, venousintervention and TIPS. Because of possible neurotoxicity,COz was not used arterially above the diaphragm.
RESULTS: CO2
runoff studies, including imaging the feet,were considered diagnostic with COz alone in 88% and COzplus a small amount of iodinated contrast in 97%. The otherCOz studies, including 20 PTAs, 30 stents, 10 embolizationsand 50 TIPS, were comparable to iodinated contrast. CO,was ofparticular importance for renal angioplasties and stentplacement, since the low viscosity COzcan be injected betweenthe stent catheter and guidewire, always visualizing the aortorenal junction, and improving the accuracy ofstent placement.No significant increase in renal failure occurred.
CONCLUSION: The plastic bag permits easy, safe, controlleddelivery ofCOz' without significant increase in renal failure,pain or intestinal ischemia when delivered in small volumes.
Poster No. 256
Thrombosis and Thromboembolism Risk from a DistalProtection Device: Effects of Device Geometry andHeparin Coating.1.L. Pavlovic, Microvena Corporation, White Bear Lake,MN· KD. Anderson· S. Sukavaneshvar • Y Zheng
PURPOSE: Interventional procedures have triggered the needfor distal embolic protection devices (DEPs) to minimizethromboembolic risk. However, there may be a risk of inherentthromboembolism from the DEPs themsclves. This studywas designed to assess the relative thrombotic and embolicpotential of DEPs.
MATERIALS AND METHODS: Braided nitinol DEPs weretested (n=6 per group): I) bell-shaped, with and without abonded heparin coating, and 2) bell- and cone-shaped, eachwith a bonded heparin coating. In ~itro paired comparisonswere performed in a one-pass parallel flow system using freshbovinc blood from 3 animals (2 tests/animal) at 37°C andACT range = 200-300 sec. Flow was maintained at 30ml/minfor 6-21 minutes. A light-scattering microemboli detector(LSMD) was used to continuously detect distal thromboemboli> IOOJ.l.m in flowing blood. Pressure gages distal to the DEPsmonitored changes resulting from thrombotic occlusion ofthedevices. Tests were stopped when a pressure change>30mml-lg occurred in either channel, indicating filterocclusion. IIIIn labeled platelets were used to quantify thrombiadherent on retrieved DEPs.
cone design (ee)·P<O.05, paired HeSI for categoricaJ variables (ex.cluding one outlier)"P<O.05, paired I·lest for quantitalive variables (ex.cluding one outlier)Visual and SEM analyses venfied the tabulated results.
CONCLUSION: This in vitro study enabled comparativeassessment of thrombogenic and thromboembolic potentialof DEPs under identical test conditions. The results showthat a DEP with bonded heparin coating was less thrombogenicthan the identical uncoated DEP. A cone-shaped DEP wasless thrombogenic than a bell-shaped DEP. These observationssuggest that: I) DEPs present an inherent risk of thrombosis,2) a heparin coating significantly reduces this risk, 3) devicegeometry may significantly influence thrombogenic potential,and 4) although further validation is necessary, embolizationwas not a major concern for the duration of these tests.
Poster No. 257
Feasibility of a Novel Endovascular System forAdventitial Delivery of Drugs.MK. Razavi, Stanford University Hospital, Stanford, CA,USA·1.M Waugh· K Seward· 1. Wilbllr· L. Barr
PURPOSE: To study the feasibility of a novel endovascularmethod for adventitial drug delivery to inhibit neointimalproliferation after angioplasty/stenting.
MATERIALS AND METHODS: The device consists ofa 5 Frflexible over-the-wire catheter with 4 additional lumina forfluid transfer. These are coupled with 100 mm diametermicroneedle ofvariable length enclosed in a C-shaped paryleneballoon actuator. The needles have a series of50 mm ports forinjection. Initially the aortae on New Zealand White rabbitswere injected with a solution of silver nitrate at 3 differentplaces each to pinpoint the perivascular location ofinjection.The aortae were explanted 15 minutes after injection and
analyzed histologically. In the next phase ofthe study tritiatedrapamycin was injected in the vascular wall ofballoon injuredporcine coronary arteries and drug distribution studied.Rapamycin was chosen because of its anti-proliferativeproperties.
RESULTS: Catheter and balloon delivery was successful inall animals. Actuation and retraction of the system occurredduring each injection. Silver nitrate was localized to the mediaand/or adventitia ofthc rabbit aorta depending on the lengthof the needle used. Similarly, distribution of radiolabeledrapamycin in the vascular wall was detennined.
CONCLUSION: The system presented is an effective methodfor perivascular drug delivery without additional intimal injury.It can be used in conjunction with PTAIstenting or in place ofdrug coated stents to limit vascular restenosis
Neurointerventions
Poster No. 258
Percutaneous Repair of Carotid Berry Aneurysm with aRetrievable Uncovered Nitinol Graft.X G1I, AGA Medical Corporation, Golden Valley, MN, USA• H. Kong· M Urness· 1.L. Titus· D. W Hunter· KAmplatz
PURPOSE: Berry aneurysm of the cerebral arteries is themost common and lethal form of false aneurysm. In recentyears, percutaneous techniques have been developed whichbasically consist ofthe introduction ofcoils into the aneurysmin order to produce thrombosis. This technique however isless than satisfactory and sometime supplemented by theinsertion of a stent to confine the coils in the aneurysm. Thepurpose of this study is to evaluate the efficacy ofa retrievable,uncovered Nitinol graft for endovascular repair ofcarotid berryaneurysm in a canine model.
MATERIALS AND METHODS: The berry aneurysm wassurgically created in 6 adult dogs 12 carotid arteries by suturinga Gore-Tex patch to the carotid artery. The mean diameter ofthe carotid arteries was 4.06 ± 0.46 mm (range from 3.2 to 5mm). The graft is constructed of 72 (0.003" eaeh) or 144(0.002" each) Nitinol filaments with a microscrew forattachment to the delivery cable. The mean diameter of thegraft was 4.88 ± 067 mm (range from 4 to 6 mm), and thelength ofthe graft was 19.58 ± 6.26 mm (range from 12 to 31rom). Seven to fourteen days after surgery, angiography wasperformed from the femoral approach to documcnt size andshape of the aneurysm. Via a 6-F long delivery sheath, thenitinol graft was placed in the carotid artery to cover themouth of the aneurysm. A balloon catheter was then used topush thc graft wires firmly against the wall of the carotidartery. An angiogram was performed immediately afterballooning, at one week, one month and three months after theplacement. No heparin or other anticoagulants were used duringor after the graft placement in first 4 animals.
RESULTS: All grafts were successfully deployed on the firstattempt. Angiography showed that all the grafts and carotidarteries were patent after graft placement. Mural thrombosison the graft surface could be identified in two arteries. Theaneurysmal cavity could not be visualized in II of 12 carotidarteries after graft placement, and I of 12 carotid arteries at 1week follow up. Follow up angiogram from one week to threemonths showed 10 of 12 grafts remaining patent withoutrecurrence ofthe aneurysm, but the other 2 were thrombosed(both of them without using anticoagulants during or aftergraft placement). There was no evidence of graft migrationupon follow up angiography. Two grafts were placed across S89
