secondary intervention patients were subjected to a followup protocol that required a contrast enhanced spiral ct scan 23 days post procedure, after 3,6 and 12 months and yearly thereafter. RESULTS: No complications were noted during placement of the Talent extender cuffs. Completion angiography showed open renal arteries and renewed aneurysm exclusion in all cases. Mean postoperative follow-up was 5.1 months (range 3-9). On pre-discharge CT scan an endoleak (of unknown origin) was seen in I patient. This endoleak had resolved spontaneously by 3 months. During follow up treated endoleaks did not relapse. CT scans could not detect renal parenchyma perfusion defects and pre and postoperative creatinine serum levels were similar in all patients. CONCLUSION: Custom made Talent extender cuffs enhance the possi.bilities for endovascular repair of endoleaks. Transrenal fixation ofTalent extender cuffs is safe and endoleak exclusion seems to be effective. These short-term observations may contribute to regulatory guidelines for combining different stent graft systems for endovascular treatment of endoleaks.
StentslAtherosclerosis Poster No. 250 The Effect of a 2B/3A Receptor Inhibitor on Thrombus Formation with Covered Stent Placement, a Feasibility Study. K. Dowling, Albany Medical Center, Albany, NY, USA· B. Paulus· E. G. Dolen· S. Quarfordt • B.F Stainken • G.P Siskin, et al. PURPOSE: Thrombus formation has been problematic with the use of certain coverings on intravascular metallic stents. The purpose was to determine, in a canine model, the effect of the platelet inhibitor Tirobifan (Merck) on thrombus formation in stents coated with a polyurethane/silicon mixture. MATERIALS AND METHODS: Animal care and use committee approval was first obtained. Six animals were divided into 3 groups to be sacrificed at 2, 4, 6 weeks. Wallstents (Boston Scientific) were coated with a polyurethane/silicon compound (Cardiothane-51, Arrow). A covered and non-covered Wallstent were placed in each animal via a 6F sheath. One animal in each group recieved a loading dose and infusion of Tirobifan. Histopathological analysis was performed. RESULTS: Angiography showed minimal «10%) neointimal hyperplasia and no discrete thrombus. Histologically the covered and noncovered stents respectively showed an average stenosis at mid stent of7% and 3% in the Tirobifan group and 8% and 4% in the non drug group. No thrombus was seen. Neointimal hyperplasia was slightly greater in the ends ofthe stents but not significantly greater in the drug versus non drug groups. CONCLUSION: Tirobifan conferred no advantage in thrombus or neointimal hyperplasia formation as compared to aspirin and herparin alone. Because of its smaller profile this covered stent may have human application.
Poster No. 251 Highly Stretchable Stents and Related Devices: A New Concept. A. Konya, UT M.D. Anderson Cancer Center, Houston, TX, USA • K. C. Wright PURPOSE: To fabricate and bench test new self-expanding nitinol stents, filters and occluders that are highly stretchable so as to achieve a small profile for transcatheter delivery. MATERIALS AND METHODS: Four distinct highly stretchable straight tube-stents, two IVC filters, and two occluders were fabricated. The devices were made from nitinol wire to which a shape memory was imparted. Both ends of the device were attached to a coaxial delivery system for precise controlled delivery. The devices were bench-tested for stretchability, low prOfile, and retrievability/ repositionability in an adequately sized transparent tube. RESULTS: All of the devices tested were highly stretchable; they could be elongated 2 to 5 times their unconstrained length. The maximal elongation of a device depended on the unconstrained diameter of the device as well as the design pattern. While still attached to the delivery system, the device could be easily expanded to determine its precise location and then re-stretched and repositioned before deployment. After establishing optimal contact with the wall of the transparent tube in the desired location, the device was deployed by releasing its ends in succession. CONCLUSION: High stretchability of a steot or stent-based device coupled with a completely controlled delivery mechanism offers a new approach for precise transcatheter delivery ofself-expanding devices. Poster No. 252 Primary Stenting for Renal Artery Stenosis Secondary to Atherosclerosis. K. Dowling, Albany Medical Center, Albany, NY, USA • J Wong· G.P Siskin· E.G. Dolen· S.D. Quarfordt· K. Mandato, et at. PURPOSE: The purpose of this study is to evaluate the outcomes for treatment of hypertension by primary stenting in atherosclerotic related hypertension. MATERIALS AND METHODS: In this retrospective study patients treated by stenting of renal artery stenosis secondary to atherosclerosis with hypertension were evaluated. Comorbid states as well blood pressure measurements were documented. Follow-up was performed with ultrasound. Complications were also documented. RESULTS: A total 100 renal arteries were stented in 90 patients. Stent placement was technically successful in all cases. Sixty patients (67%) were treated for hypertension. Five patients (5.5%) for azotemia and 25 (28%) for both hypertension and azotemia. The average follow-up was II months (1-49 months). Comorbid states included diabetes mellitus (21 %), coronary artery disease (36%), positive smoking history (51 %), peripheral vascular disease (26%) and CVA (3%). Ninety-six percent of the stenoses were paraostial. The average present systolic blood pressure was 163mm1hg and the post stent systolic blood pressure was I47mm1hg. The average diastolic blood pressure was 84mm! hg and the average post stent diastolic pressure was 75mml hg. Sixty-nine percent of patients had improvement of their blood pressure. Reintervention was performed on II patients; 6 patients receiving PTA only and 5 re-stenting. There was a 10% complication rate: 7 groin hematoma, 3 dissection and I thrombosis.
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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 ofintravascular ultrasonic ablation in patients with atherosclerosis obliterans. MATERIALS AND METHODS: 56 patients ofatherosclerotic 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 4~ 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. A 8 week follow-up showed reocclusions in 2 patients one year followup 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 ofconb'ast medium in acute renal failure rats. MATERIALS AND METHODS: 110 male rats weighing 250300 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.
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RESULTS: The ARF was perfonned succcssfully in 80 ratsl I J0 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 ofinjection. In the MRI groups, the MR scans showed good image in the standard and high dose ofinjection. There was no significantly different creatinine level between CT and MR groups (P=O. 116). There was no significant difference 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 ofFlorida, 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 compressibility~ 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 ofexcessive 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 ofCOr 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 ofparticular 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 aortorenal junction, and improving the accuracy of stent placement. No significant increase in renal failure occurred. CONCLUSION: The plastic bag permits easy, safe, controlled delivery ofCOz' without significant increase in renal failure, pain or intestinal ischemia when delivered in small volumes.