Scientific Session 14 Endovascular Repair of Abdominal Aortic Aneurysms: Endoleaks

a safe therapy in our experience. 50% of these patients demonstrated either tumor response or disease stability.

2:36 pm

Abstract No. 103

Radiofrequency Induced Thermal Ablation (RITA) of Primary and Metastatic Liver Tumors: Results in 90 Consecutive Patients. A. Veltri, University of Turin (Italy), Turin, Italy· P Hosseinollahi • F Barisone • D. Campanella • M. Gallizioli • G. Gandini PURPOSE: To evaluate the mid-term results of RITA in hepatic tumors. MATERIALS AND METHODS: Between March 1996 and August 2000, we treated 33 patients with HCC and 57 with metastases; the metastases were from colon cancer (45 pts), breast cancer (4 pts), and other tumors (8 pts). One-hundred-forty-six RITA sessions 035 percLltaneous, 11 intraoperative; 124 "Simple", 22 combined with TACE, arterial or portal stop-flow, or Pringle maneuvre) were performed in 137 lesions 0-9 per patient, mean 1.5; size 10-80 mm, median 27 mm); particularly, 24/41 HCC were residual lesions after PEL The local results were first evaluated by CT; the patients were then fulloweJ-up clinically and by US/CT. RESULTS: Adverse events (no mortality) occurred in 10% patients (4% in simple treatments, 18% in combined procedures). Early CT-study showed complete necrosis in 105/137 (77%) lesions, but during the follOW-Up 0-54 months, mean 15 months) lasting local control was achieved only in 84/137 (61%: 67% in metastases; 49% in HCC overall, 71% in not previously treated nodules); causes for recurrence were larger size and partial fibrosis in residual HCe. Up to now, 97% HCC and 72% metastatic patients are still alive, but only 29% are disease free (28% HCC pts and 30% metastatic pts). Higher mid-term survival rate of HCC was probably due to the slower natural course of the disease. [n metastatic patients, RITA was combined with other antitumoral therapies in 74% patients and followed by tumor recurrence in the same or in other site in 58%; so, only 140/0 are alive and disease free without other therapies after one year. CONCLUSION: RITA is relatively safe and quite effective in obtaining local control of primary and metastatic liver tumors; its clinical success depends on patients selection and other integrated oncologic therapies.

(RFA) of soft tissue neoplasms, and to describe methods to avoid complications in specific clinical settings. SUB]ECTS AND METHODS: Percutaneous image-guided RFA treatment sessions were performed on 150 tumors in 70 patients over 24 months. Tumor histology included melanoma, ovarian carcinoma, fallopian tube carcinoma, hepatocellular carcinoma, sarcoma, colon carcinoma, adenocarcinoma of unknown origin, pheochromocytoma, renal cell carcinoma, adrenocortical carcinoma, neuroendocrine, insulinoma, and osteode osteoma. Tumor locations included liver, kidney, aXilla, flank, back, paraspinal muscles, suprarenal, renal hilum, adrenal, groin, adnexa, perirectal pelvis, pericolonic gutter, rib, pleura, spleen and vertebral body. Treated tumors abutted vital structures, including colon, rectum, small bowel, gallbladder, stomach, spleen, pancreas, lung, diaphragm, kidney, bladder, vagina, brachial plexus, aSCites, aorta, renal vein, ureter, celiac artery, common femoral artery, common femoral vein, main hepatic vein, main portal vein, inferior vena cava, and right atrium. RESULTS: All patients went home or were off service from 6 to 23 hours after the procedure without major complication. The treatment margin included non-target organs in several cases. One patient with a nearby colostomy had a delayed wound infection, and one patient had transient weakness in leg extension. Five pleural effusions were noted, one of which requi.red pleurodesis. Methods of protecting non-target organs included ice bags, pro-peristaltic drugs, chilled enema, bladder emptying, paracentesis, intraprocedural neurological exams, and appropriate sedation, analgesia, or anestheSia, as well as intraprocedural temperature monitoring. CONCLUSION Percutaneous, image-guided RFA can be a safe and well-tolerated procedure. ProXimity to vital organs should not be an absolute contraindication to percutaneous RFA. However, simple precautions may minimize the risk of complications.

Scientific Session 14 Endovascular Repair of Abdominal Aortic Aneurysms: Endoleaks Moderator: Brian Stainken, MD

Tuesday, March 6, 2001 1:30 pm-3:00 pm 1:30 pm

2:47pm

842

Abstract No. 104

Abstract No. 105

Avoiding Complications in Radiofrequency Tumor Ablation. Bj. Wood, National Institutes ofHealth, Bethesda, MD, USA • I. Mikityansky • C. PavlOVich • R. Chang • M. Walther· S. Libutti, et at.

Association of Coumadin Therapy and Endoleak Following Endovascular Repair of Abdominal Aortic Aneurysm. J.D. Goodman, UCSF, San hancisco, CA, USA • }.M. LaBerge • TA. Chuter • L. Reilly· R. Sawhney • R.K. Kerlan, et at.

OB]ECITVE: To assess the safety and potential complications of outpatient percutaneous radiofrequency ablation

PURPOSE: EndoJeaks are encountered in up to 45% of patients following endovascular repair of abdominal

aortic aneurysm (AAA). However, risk factors for the development of endoleaks have not been clearly identified. The purpose of this study is to determine if coumadin use is a risk factor for the development of an endoleak. MATERIALS AND METHODS: We retrospectively reviewed the records of all patients who underwent endovascular AAA repair over a 4-year period. Data collected included pre-and post-operative imaging findings by angiography and contrast-enhanced CT, technical data at stent-graft insertion, and follow-up clinical evaluation. Patients on coumadin prior to the procedure were identified. In all of these patients, perioperative coumadin was withheld and anticoagulation was reinitiated after the procedure. Coumadin therapy and the presence of endoleak on follow-up CT were treated as dichotomous variables analyzed using the Chi square test. RESULTS: One hundred and Sixty-one patients underwent AAA repair (153 men and 8 women, mean age of 75.2 years). Mean maximal aneurysm diameter was 6.28 cm. Stent-grafts were either unilateral Chuter grafts (n=115), Zenith bifurcated grafts (n=34), or aorto-aorto tube grafts (n=12). Twelve of 161 patients (75%) were on coumadin. Fony-one of 161 patients (255%) developed an endoleak. Of the 41 patients with endoleak, 6 were on coumadin (14.6%) and 35 were not (85.4%). Of the 120 patients without endoleak, 6 were on coumadin (50/0) and 114 were not (95%). Six of 12 patients on coumadin developed a leak (50%) while 35 of 149 patients not on coumadin (23.5%) developed a leak. The relative risk of developing an endoleak for patients treated by coumadin compared to those not on coumadin was 2.13 (95% CI: 1.13 - 4.02, p=.042). CONCLUSION: Coumadin is a significant risk factor for endoleak. Patients on coumadin are twice as likely to develop endoleaks than patients not on coumadin. However, since the majority of patients who develop endoleaks are not on coumadin, additional risk factors should be investigated. 1:41 pm

Abstract No. 106

Mid Term Clinical Follow-up of Aortic Aneurysm Sac Shrinkage after Percutaneous Coil Embolization of Endoleaks. N.B. Amesur, University ofPittsburgh Medical Center, Pittsburgh, PA, USA • A.B. Zajko • PD. Orons • D. Bertges • M.S. Makaroun PURPOSE: Persistent endoleaks follOWing endovascular treatment of abdominal aortic aneurysms (AAA) are now widely reported. This complication can result in continued growth of the aneurysm sac and possible aneUlysm rupture. Percutaneous coil embolization of persiscent endoleaks is a minimally invasive treatment option. Our experience and clinical follow-up in such patients is presented.

MATERiALS AND METI-JODS: 168 patients with AAA were treated with the Ancure-Endovascular Technologies (EVf) System since 1996 at our institiution. Initial endoleaks occurred in 33 (20%) patients. ine patients had persistent endoleaks at six months (5% of overall and 27% of patients with initial endoleaks). Eight of these patients underwent a total of 11 percutaneous coil embolization procedures to embolize the sac as well as the communicating vessels. AneUlysm sac size was followed by color flow duplex and CT. RESULTS: Seven of the eight patients were successfully embolized. One patient could not be embolized due to presence of a Wallstent across the distal anchoring mechanism and required treatment with a covered stent to seal the persistent endoleak. Anelllysm size decreased in all patients (mean reduction of 0.9 cm, range 0.1-2.4 cm) during a mean follOW-lip of 19 months, range 3-30 months. There has been no aneurysm rupture or rupture related deaths. No recurrent endoleaks or enlargement of the aneulysm sac was seen after a successful embolization procedure. CONCLUSION: At our institution, percutaneous coil embolization of the aneurysm sac and outflow vessels has been successful in sealing persistent endoleaks and decreasing aneurysm sac size after AAA treatment with the Ancure endograft.

1:52 pm

Abstract No. 107

Abdominal Aortic Aneurysm Enlargement without Endoleak Following Endovascular Repair: A Review of the Imaging Findings. DA. Gould, Royal Liverpool Hospital, Liverpool, UK, United Kingdom • R.G. McWilliams • M.F Badran • J. Martin • G.L. GilNng Smith • PI. Harris, et al. PURPOSE: To review cases where aneulysm sac enlargement after abdominal aortic aneurysm (AAA) endovascular repair (EVR) appears unassociated with endoleak on imaging studies. MATERiALS AND METHODS: 86 patients underwent EVR of AAA. Spiral, contrast enhanced computed tomography (CT) was performed for preoperative and follow up assessment. Cases with aneurysm sacs which had enlarged between the preoperative and latest follow up studies, and who had no apparent associated endoleak, were reviewed with particular reference to axial and reconstructed CT images. Reintervention was considered, depending on the imaging findings. RESULTS: Five patients with enlarging sacs had imaging studies which were negative for endoleak. Mean aneUlysm sac diameter in these cases was 7.1 (range 55-7.9) cms and mean diameter change from implant date was +8.3 (range +5 to +22) mm. Mean follow up was 355 (range 24-48) months. In four cases (5 iliac limbs) there was <1 ern of common iliac stentgraft coverage: in addition, one stentgraft limb was undersized by 2mm. None of these cases had had a demonstrable

843

endoleak at any time. Two have been managed by stentgraft extensions and two are under review. The fifth case had had spontaneous resolution of a prima!y proximal endoleak on 3 month CT and no subsequent demonstration of endoleak on imaging. At surgical conversion for unexplained sac enlargement at 24m, spontaneous, massive arterial bleeding was seen around the upper end of the device. CONCLUSION Potential pathways for systolic pressure lransmission may exist in association with sac enlargement despite absence of endoleak on imaging studies. The occurrence of this situation warrants consideration of reintervention.

2:03 pill

Abstract No. 108

What Does the UK Registry of Endovascular Treatment of AbdomJnal Aortic AnenryslllS (RETA) Tell Us about the Fate of Patients with Primary Endoleaks. S.M. Thomas, Sheffield Vascular Institute, Sheffield, United Kingdom. FA. Gaines. J.D. Beard

PURPOSE.' To present the follow up of patients with primary endoleaks identified in the peri-procedural period to establish the likely fate and consequences of these endoleaks. MATERIAlS AND MEJ1-.IODS: There were 123 primary

endoleaks in the 1000 cases forming RETA visualised either immediately post procedure or at 30 day cr scanning. The site of these were: collateral 42 (34%); proximal anastomotic (PA) 41 (34%); Distal anastomotic (DA) 1905%); midgraft 12 (9.6%); occluder 3 (2.4%); and the site was not stated in 6 (50/0). The fate of these endoleaks was examined from available follow up data. RESULTS: 9 (22%) patients with PA endoleaks died of rupture (n=3) or following surgery for the endoleak (n=6). 11 patients had persistent primary PA endoleak with or without treatment, of these the rupture rate was 27% (3/11). Others were successfully treated with surgery, proximal cuffs or angioplasty of the PA. 22 (52%) collateral endoleaks resolved spontaneously at 30days. There \I/ere no ruptures al fol1O\I/ up. 7 (37%) VA endoleaks resolved spontaneously by 30d and 4 had further endovascular treatment prior lo discharge. Of the 8 persistent endoleaks 3 resolved spontaneously and three had endovascular treatment. There were no ruptures at follow up. 2 (66%) occluder endoleaks resolved spontaneously, the other died suddenly of unknown cause (?rupture) al follO\\! up. 9 05%) rnidgraft endoleaks resolved by 30d and one had resolved spontaneously at 1 year, again there were no ruptures in this group.

844

COIVCLUSION The presence of a PA endoleak justifies an aggressive approach to treatment because of the association of these endoleaks with AAA mpture. However, open surgical treatments carry a significant mortality. Other endoleaks follow a more benign course and many will resolve spontaneollsly at early follow up.

2:14pm

Abstract No. 109

Endoleaks: Predictable, Preventable and Often Treatable? D.O. Kessel, The United leeds Hospitals, Leeds, United Kingdom. I. Robenson • Lf. Denton· ]. Patel PURPOSE: To highlight the prevalence of endoleaks following endovascular repair of abdominal aortic aneurysm (EVAR) and the importance of preoperative imaging if lhey are to be prevented.

MATERIALS AND ME.7HODS, EVAR was performed in 40 patients. Pre-operative imaging included spiral CT and calibrated angiography. Stent grafts were deployed by radiologists and surgeons in the vascular interventional suite. Follow up was with dual phase CT and colour Doppler ultrasound. Endoleaks were recorded and when pOSSible treated by embolization or further stent grafting.

RESULTS: Aneurysm exclusion was achieved in 38 (95%) with 1 (2.5%) type III and 1 type II Endoleak. All grafts remain patent al a median follow up of 18 months. There have been no type I leaks but 6 04%) of patients have developed type II endoleaks and 1 (2.5%) a type III leak. 16 patients had a patent inferior mesenteric artery (IMA) and 21 had patent lumbar arteries. Pre-operative embolization of the IMA (n=]3) and lumbar arteries (n=9) was performed and no type II leaks developed in these patients. 6 of 12 (50%) of patients with patent lumbar arteries developed type II endo leaks. Patients with type II leaks frequently showed an increase in aneurysm size on CT. Embolization eliminated the leak in 4 patients but did not succeed in 2. CONCLUSION Patent collateral vessels predispose to type II endoleak. Pre-operative embolization protects against subsequent leak developing. Subsequent cmbolotherapy is time consuming, expensive and does not always succeed. Type I leaks can be avoided in appropriately selected patient,>.

2:25 pill

Abstract No. 110

Treatment of Type n Endoleaks with Onyx. ML Mantn, UBC Hospital, Vancouver, Be, Canada. BL Dolmatch • PD. Fry • L.S. Machan

PURPOSE: Type II endoleaks, defined as persistent collateral perfusion of an abdominal aorlic aneulysm (AAA) after endovascular stent-grafLing, may place patients at risk for continued sac expansion and delayed aneurysm mpturc. We describe our experience treating type II endoleaks with the liquid embolic agent Onyx (ethylene-vinyl-alcohol copolymer, Micro Therapeutics Inc. (MTI), IIvine CAl. MATERIAlS AND /I/IEmODS: Five patients who had un-

dergone endovascular stent grafting of an abdominal aortic aneurysm at our institution were found at followup imaging to have persistent type II endoleaks. One patient had two concurrent leaks. Two of the patients

were symptomatic with tender, pulsatile aneurysms. Endoleak access was attempted with direct translumbar puncture (n=4) or retrograde catheterization (n=2) and Onyx injected into the endoleak sac. RESULTS: Procedure times varied from 1 to 2.5 hours (mean = ].8 hrs). Complete endoleak occlusion was achieved in five of six leaks. F9llow-uP imaging has been performed in four patients. all of whom experienced decreased aneurysm diameter. Both symptomatic patients became asymptomatic after embolization. All patients remain well ]0 to 28 weeks (mean = ] 9.4 weeks) after treatment. CONCLUSION: In short term follow-up. Onyx was an effective agent in this series of patients. sing a liquid embolic agent such as Onyx instead of coils to treat type II endoleaks may result in more effective and durable type II endoleak occlusion.

2:36 pm

Abstract No. 111

Change in Abdominal Aortic Aneurysm Diameter at One-Year after Endovascular Repair. M.e. Farner, Hospital ofthe University ofPennsylvania, Philadelphia, PA, USA. RA. Baum • D.]acobs • ]. Carpenter • RM. Fairman PURPOSE: Endovascular repair of abdominal aortic aneurysm (AAA) is expected to alter the natural progression of diameter increase and rupture. The purpose of this study is to determine the rate of diameter change in AAA treated by endovascular repair. MATERIALS AND METHODS: Sixty-three patients underwent endovascular repair for AAA and at least 7-month follow-up by computed tomography angiography (CfA) or magnetic resonance angiography (MRA). Maximal cross··sectional aneurysm outer diameter was measured for serial CTA/MRA. Immediate post-repair CTA/MRA was used fm comparison to follow-up studies. Endoleak was also evaluated. RESULTS: Mean follow-up interval is 12 months C7 to 21 months). Preoperative and immediate post-repair maximal outer diameters correlate closely (r = 0.945; P
Three of 5 patients with diameter increase at follow-up had no endoleak. CONCLUSION: Endovascular treatment of AAA results in a significant reduction of maximal outer diameter. Patients with treated endoleak have no significant difference in AAA diameter reduction compared to those without endoleak. The presence of a persistent endoleak can result in diameter increase. Patients without endoleak may not demonstrate diameter reduction and further investigation is necessary.

2:47 pm

Abstract No. 112

Use of Aortic Cuffs to Seal mac Aneurysms during AneuRx Endograft Repair of Abdominal Aortic Aneurysms: Initial Experience. D.B. Brown, Mallinckrodt Institute a/Radiology, St. Louis, MO, USA • L.A. Sanchez • D.M. Hovsepian • B.G. Rubin • GA. Sicard • D. Picus PURPOSE: Up to 47% of patients who undergo aortic endografting for abdominal aortic aneurysm disease will have dilation of the iliac arteries requiring intervention. Coil embolization of the internal iliac artery and extension of the graft to the external iliac artery is one solution to this problem. However, 19-41% of these patients experience buttock claudication which may be permanent following unilateral embolization. We examined an alternative: sealing the common iliac artery aneurysms with aortic cuffs, and present .our outcomes and short-term results. MATERIALS AND METHODS: From October 1999-August 2000, 144 AneuRx stent-grafts were placed at our institution. In this population, 14 patients had 15 aortic cuffs placed below the iliac limbs (14 mm, N=2; 15 mm, N=4; 16 mm, N=9) to seal areas of common iliac artery dilation. One patient had bilateral cuffs placed. Of the cuffs placed, 4 were 20mm, 6 were 22 mm, 2 were 24 mm, 2 were 26 mm, and :I was 28 mm. Five patients had embolization of the contralateral internal iliac artery because of bilateral disease. Patients were followed using 3-dimensional spiral computed tomography (CT) at 1, 6. and 12 months to evaluate for endoleaks. RESULTS: Follow-up CT scans demonstrated no endoleaks in any of the patients. There was imaging follow-up up to 6 months in 4 patients and 1 month in 8 patients. One patient declined Cf but was alive and well 7 months after endografting. The last patient moved across the country and was lost to follow-up. One patient of the 5 who had internal iliac.artelY embolization had claudication. CONCLUSION: Placing aOltic cuffs in dilated iliac arteries can preselve flow to the ipsilateral internal iliac artelY while providing an adequate seal. Additionally, the option of later treatment is maintained. Patients with bilateral iliac ectasia can undergo stent-graft placement without bilateral internal iliac artery embolization. Longer-term follow-up in larger numbers of patients will be important to determine the ultimate durability of this technique.

845