Abstract No. 278: Exothermic Electrophiles for Thermochemical Ablation Assessed in a Gel Phantom

Vascular Interventions: Stent Graft

Abstract No. 278

Exothermic Electrophiles for Thermochemical AblationAssessed in a Gel Phantom.N.D. Frank, T.L. Brix, E.N.K. Cressman; University ofMinnesota Medical School, Minneapolis, MN

PURPOSE: To evaluate Acetyl Chloride and Acetic Anhy-dride for utility in thermochemical ablation.

MATERIALS AND METHODS: Acetyl Chloride and AceticAnhydride were each reacted with 19.1M, 15M, 10M, and5M concentrations of NaOH in volumes that satisfied thestoichiometry of the reactions with 100 ul of each electro-phile. All reactions were carried out in a gel phantompreviously reported by our group. Five trials were con-ducted for each electrophile/NaOH combination. For eachtrial, the proper volume of NaOH was introduced by syringesuch that a bubble of NaOH was suspended in the gel. Theelectrophile being investigated was then injected over 5seconds into the NaOH creating a reaction bubble in the gelmedium. Temperature was measured in 15 second intervalsover a 5-minute period with a probe positioned in the gel 5mm away from the edge of the reaction bubble. A total of 40injections were studied for the 8 combinations with aver-ages reported for the five runs.

RESULTS: Temperature changes of 0.9-3.4 deg C wererecorded. All combinations produced an average tempera-ture increase of more than 2.0 deg C except those betweenAcetic Anhydride and both 10M and 5M NaOH whichaveraged 0.9 and 1.28 deg increases respectively. Trials ofthe combinations of Acetic Anhydride/15M NaOH andAcetyl Chloride/5M NaOH each averaged a temperatureincrease of 3.44 degrees.

CONCLUSION: Temperature changes recorded in the gelusing microscale reactions show potential utility in thermo-chemical ablation. This is remarkable considering both thesmall scale and the insulating characteristics of the gelwhere the measurements were obtained. Heat released wasgenerally in line with predictions from bond energetics, butas with other studies in our lab, viscosity of high concen-trations of NaOH and other yet undetermined factors maybe interfering with optimal mixing and thus heat generation.Further investigation with cautious scale-up is warranted.

Abstract No. 279

Amplatzer® Vascular Plug Occlusion of the Left Sub-clavian or Celiac Artery Prior to Endograft AneurysmRepair.D.E. Hendricks, K.D. Hagspiel, J.F. Angle, B. Arslan,U.C. Turba, U. Bozlar, M.H. Alan, M.D. Dake; Universityof Virginia Health System, Charlottesville, VA

PURPOSE: To review our experience with the Amplatzer®vascular plug (AVP) for prevention of type II endoleaksduring endovascular treatment of thoracoabdominal aorticaneurysms using endografts.

MATERIALS AND METHODS: Retrospective review of allpatients seen at our institution who underwent occlusion ofaortic side branches as an adjunct to endograft repair ofthoracoabdominal aneurysms with the AVP. Procedure re-ports, charts, and follow-up imaging were reviewed. Proce-dural criteria evaluated were primary vessel occlusion fol-lowing AVP and the use of adjunctive embolic agents.

Follow up imaging criteria included target vessel occlusionand the presence and characterization of endoleak second-ary to AVP failure.

RESULTS: There were 9 consecutive patients from 8/3/05through 10/18/06 who underwent transcatheter occlusion ofeither the left subclavian (n�7) or celiac artery (n�2) priorto endograft repair of thoracic and thoracoabdominal aorticaneurysms. All procedures achieved technical success withcomplete vessel occlusion documented angiographically atthe conclusion of the procedure. In 8 of the 9 cases, embo-lization was achieved solely using the AVP. Additionalcoils were required in a single case. CTA or MRA follow-upimaging was available for all patients (mean follow up time339 days, range 47-527 days) with no evidence of vesselrecanalization or type II endoleak due to AVP failure.

CONCLUSION: Transcatheter arterial occlusion of the sub-clavian and celiac arteries using the AVP is a valuableadjunct to endografting in cases where side branch emboli-zation is necessary to extend the landing zone and preventtype II endoleaks.

Abstract No. 280

Total Percutanous Endovascular Aneuryms Repair(TPAR): The Dual 6F Closer-AT™ Preclose Technique.T. Jahnke,1 P.J. Schaefer,1 M. Siggelkow,2 N. Charalambous,1

T.H. Huemme,1 M. Heller,1 S. Mueller-Huelsbeck;1 1De-partment of Radiology, UKSH, Campus Kiel, Kiel, Ger-many; 2Department of Vascular Surgery, UKSH, CampusKiel, Kiel, Germany

PURPOSE: Prospective study to determine safety and effi-cacy of total percutanous endovascular aneurysm repair(TPAR) with a suture-mediated preclosing technique.

MATERIALS AND METHODS: 57 femoral access sites in29 consecutive EVAR patients were closed percutaneouslywith two F6 Perclose closure devices (Perclose Closer-AT™; Abbot, USA) preapplied in 90° angle. Femoral ac-cess ranged from 12-24 F (24F: n�1; 22F: n�2; 20F: n�6;18F: n�32; 12F: n�16). TPAR was performed with Ex-cluder (Gore, Flagstaff, USA) in 24/29, and Talent prosthe-ses (Medtronic, USA) in 5/29 cases. Initial success, durationof the procedure and access closure times, as well as im-mediate and 30 day complication rates were documented.Patients were followed clinically and with CT/MRI fordetection of groin complications. A groin hematoma/scarseverity score (grade 1-3) was generated from the CT/ MRdata at 3 days, and at 3, 6 and 12 months. Data werecompared to a previous cohort of patients (n�38) withsurgical cut-down.

RESULTS: Technical success of the preclosing techniquewas 93% (53/57) for all arteries. 12 F access was success-fully closed in 100% (16/16), 18-24 Faccess in 90,2%(34/37). Four technical failures (4/57) occurred (suture in-sufficiency n� 2, device entrapment n�2), but were allmanaged intraoperatively with surgical suture. There was nodevice related morbidity/ mortality, and no late access sitecomplications occurred. Mean duration of the TPAR pro-cedure was 105 min (� 41), access closure time was 10 min(� 9min). In a previous cohort of patients with surgicalgroin management mean procedure time was 153 min (�112), p�0,018), access closure time was 12 min (� 13;p�0,24). Inguinal hematoma/ scar severity score at 3 days,and 3, 6, 12 months was 1.8/ 1.1/ 1.0/ 1.0 for TPAR and 2.1/2.4/ 2.4/ 2.3 for surgical access closure respectively.

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