State of the Art
Endovascular Therapy of Aortic Aneurysms in the Era of New Approved Stent Graft

1. Zenith AAA Endovascular Graft for Abdominal Aortic Aneurysm
Department of Radiology, Nara Medical University
Kimihiko Kichikawa, Shoji Sakaguchi, Wataru Higashiura, Kiyoshi Nishimine, Masayoshi Inoue
Department of Radiology and IVR Center, Daiyukai General Hospital
Takeshi Nagata, Hideo Uchida

 We here describe the evolution of the Zenith AAA endovascular graft (Zenith AAA) for treatment of AAA. Since its first use in 1993, Zenith AAA underwent several improvements towards the current model, which has been used in more than 15,000 cases world-wide. Zenith AAA is a 3-piece modular system including a bifurcated aortic body and 2 iliac leg extensions.The device incorporates self-expanding stainless-steel Z-stents attached to a polyester graftmaterial. The bodies come in diameters from 22~ 32mm, and in 5 different lengths, which can be delivered through introducers of 18 or 20 Fr. The iliac leg extensions come in a wide range of lengths and diameters. Zenith AAA has transrenal fixation with a bare stent including barbs and hooks, and the best resistance to dislodgment, compared to other stent-grafts. A number of reports have been published on the Zenith AAA. In an analysis of results from 3 US clinical trials, reduction in sac size was greatest with Zenith, and the incidence of any endoleak lowest. Follow-up results of a prospective clinical trial in Japan showed the safety and effectiveness of Zenith AAA, which seems to be suitable for AAA in Japan. Finally the Zenith AAA acted as the platform in the development of fenestrated and branched grafts.

Key words
● Abdominal aortic aneurysm
● Stent graft
● Zenith AAA

2. Endovascular Stent-Grafting for Thoracic Aortic Aneurysms
Department of Vascular Surgery1), Center for Minimally Invasive Treatment of Cardiovascular Diseases2) Tokyo Medical University
Satoshi Kawaguchi1,2), Hiroshi Shigematsu1)

 Despite advances in operative technique and management having improved the clinical outcomes of conventional open surgical replacement for thoracic aortic aneurysms, it remains an invasive procedure especially for patients require emergency treatment. Over the past fifteen years, minimally invasive endovascular surgery using a stent graft has made significant advances in the treatment of aneur ysms. For twelve years from 1995, 627 patients with thoracic aortic aneurysms including 193 aortic dissections were treated with the endovascular technique using the SG in our hospital. We used an individually designed stent graft for each patient and for distal arch aneurysms. SG should be designed so that it has a scallop or fenestration on the graft to keep blood flow into the arch vessels. Exclusion of the aneurysms or closure of entry without endoleak were achieved within two weeks postoperatively in over 94%. Endovascular stent grafting shows potential as a safe and useful treatment for thoracic aortic diseases, but further investigation should attempt to determine its efficacy over a longer postoperative period.

Key words
● Stent
● Stent graft
● Endovascular
● Thoracic aortic aneurysms

3. Characteristics of the MK Stent Graft System for Endovascular Aortic Repair
Department of Radiology, Kanazawa University Hospital
Junichiro Sanada, Osamu Matsui

 The MK stent-graft is constructed from a self-expanding stent comprised of a braided single nitinol wire and a seamless, cylindrical woven graft made of polyester fabric. That braided structure makes it flexible and more suitable for tortuous aortic segments. However, the MK stent-graft may not conform to the cranked aortic segment or the aortic segment with drastic changes of the aortic caliber. These drawbacks may cause endoleaks, so that the proximal and distal landing zones should be covered sufficiently in such situations. The braided structure has another advantage that allocates the radial force of the stent-graft to the whole inner surface of the stent-grafted segment, because it has a wider surface area that comes in contact with the aortic inner wall. The MK stent-graft has other unique properties of superelasticity and shape memory. These characteristics allow for complex configurations and deployment through smaller profile delivery systems, so that it can be widely applied in many kinds of cases, such as a case with unsuitable anatomical configurations for commercial stent-grafts or acute aortic rupture. A better understanding of the properties of the MK stent-graft would enhance the clinical usefulness of this unique system.

Key words
● Matsui-Kitamura stent-graft
● MK stent-graft
● Thoracic aortic aneurysm
● Endovascular aortic repair
● Nitinol

4. Inoue Stent Graft in Patients with Aorto-iliac Diseases Unfit for Open Surgical Repair
Dpartment of Diagnostic Radiology and Surgery1), Keio University School of Medicine
Subaru Hashimoto, Sachio Kuribayashi, Makiko Shinohara, Seishi Nakatsuka, Kazuhiro Matsumoto
Masanori Inoue, Hideyuki Shimizu1), Ryohei Yozu1), Hideaki Obara1), Kenji Matsumoto1)
Department of Cardiovascular Surgery, Shimabara Hospital
Kanji Inoue

Thirty-two patients with growing aorto-iliac true aneurysm, pseudo-aneurysm or PAU were treated using Inoue stentgraft (ISG). All the patients were judged unfit for open surgical repair because of previous surger y, poor cardio-pulmonar y function or other co-existing morbidities. Materials included patients with poor anatomical conditions such as proximal landing zone (PLZ) 10 mm in length or PLZ with 90-degree angulation. A branched-ISG was used in patients with distal arch aneurysm, a Y-ISG for abdominal aortic aneurysm and a straight-ISG for descending thoracic aortic diseases, extra-anatomical bypass graft tear and for isolated iliac aneur ysm. Successful introduction and deployment of the device in the absence of surgical conversion or mortality, type I or III endoleaks or graft limb obstruction were achieved in all cases. There was a device-unrelated aneurysmal rupture and death in a patient with descending thoracic aneurysm sixteen months following the procedure. There were no type I or III endoleaks throughout the entire follow-up period. ISG placement in highrisk patients unfit for open surgical repair for aorto-iliac diseases is considered to be safe and highly effective. This method is the treatment of choice even in patients with poor anatomical conditions as well as those with surgical risks.

Key words
● Inoue stentgraft
● Endovascular aneurysmal repair
● Surgically high risk patients

Case Report
Transcathter Arterial Embolization of Paraspinal
Arteriovenous Fistula Caused by Percutaneous Needle
Biopsy of the Lumbar Spine : A Case Report

Department of Diagnostic Radiology, Osaka Medical Center for Cancer and Cardiovascular Disease
Nobuo Kashiwagi, Shodayu Takashima
Department of Radiology, Kansai-Rosai-Hospital
Hitoshi Watanabe
Department of Orthopedic Surgery, Ikeda Municipal Hospital
Toshiyuki Oukouchi

 Iatrogenic paraspinal arteriovenous fistulas (AVFs) usually occur as a result of puncture of the vertebral artery. We report a case of paraspinal AVF caused by a percutaneous needle biopsy of the lumbar spine. The AVF was successfully embolized with microcoils and N-butyl-cyanoacrylate (NBCA). A 74-year-old woman with a tumor of the second lumbar body underwent a percutaneous biopsy, but a definitive diagnosis could not be made. Consequently, it was decided to conduct an open biopsy ; preoperative embolization was requested to decrease intraoperative blood loss. The right second lumbar arteriogram and angio-CT showed the venous pouch in early arterial phase, draining into the right ascending lumbar vein and the right second lumbar segmental lumbar vein. This venous pouch had not been detected on the contrast enhanced CT prior to percutaneous biopsy. A diagnosis of iatrogenic AVF was made, and transarterial embolization was performed using microcoils and a 50 : 50 mixture of NBCA and Lipiodol. The estimated blood loss during surgery was 70mL. Histological examination of the right second lumbar body revealed a malignant lymphoma.

Key words
● Transcathter arterial embolization
● Iatrogenic arteriovenous fistula
● Paraspinal arteriovenous fistula
● Coil embolization

Case Report
Successful Transcatheter Arterial Embolization for
Idiopathic Rupture of the Internal Iliac Artery

Department of Radiology and Pathology1), Iida Municipal Hospital
Tomofumi Watanabe, Nobuo Ito1)
Department of Radiology and Internal Medicine1), Emergency and Critical Care Center2),
Saku Central Hospital
Mizuho Ueda, Toshikazu Watanabe, Toshikazu Furuhata1)
Kunihiko Okada2), Ai Okuda2)
Department of Radiology, Nagano Red Cross Hospital
Jyunko Miyazaki

Our patient, a man in his 20's was brought to our hospital in hemorrhagic shock one year ago. He had complained of unbearable left lumbago of sudden onset during evacuation at his home early in the morning. An abdominal CT scan revealed a massive retroperitoneal hematoma and extravasation of contrast material beside the left internal iliac artery. 3D-CT angiography revealed a pseudoaneurysm of the proximal portion of the left internal iliac artery, which was considered to be the source of bleeding. There was no evidence of pelvic trauma or other diseases that could be responsible for the pseudoaneurysm. Although the cause of the pseudoaneurysm was unclear, emergency transcatheter arterial embolization (TAE) with coils was chosen for the left internal iliac artery. After some coils were placed distal to the lesion, his blood pressure decreased and the lumbago worsened. These clinical features were thought to be due to the increased pressure in the pseudoaneurysm associated with distal embolization, and also to the increasing volume of bleeding. After some coils were placed proximal to the lesion, the symptoms disappeared and the blood flow to the lesion stopped completely. He has not suffered from any vascular complications since then.

Key words
● Transcatheter arterial embolization
● Internal iliac artery
● Idiopathic rupture

Case Report
A Case of Post-TIPS Encephalopathy Successfully Treated
by Shunt Reduction with a Original Stent-graft

Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine,
Tottori University
Yasufumi Ohuchi, Toshio Kaminou, Masayuki Hashimoto, Kimihiko Sugiura
Yasunobu Takaki, Tsuyoshi Kawai, Akira Adachi, Toshihide Ogawa

Hepatic encephalopathy (HE) is a common complication of transjugular intrahepatic portosystemic shunt (TIPS). We report a case of refractory TIPS related HE, which was successfully treated by shunt reduction with an original stent-graft. A 60-year-old woman with refractory ascites and tarry stool due to Child’s class C cirrhosis had undergone TIPS. Although tarry stool and ascites were controlled with medication following the TIPS procedure, the patient developed refractory encephalopathy five days after the TIPS. For the treatment of HE, shunt reduction was performed by the placement of a constrained stent-graft within the preexisting TIPS tract thirty days after the initial procedure. HE had been improved significantly seven days after completion of treatment. This technique was an effective method of treating TIPS related HE in our case.

Key words
● Transjugular intrahepatic portosystemicshunt
● Hepatic encephalopathy
● Shunt reduction

Case Report
External Iliac Arterio-ureteral Fistula Treated
by Transcatheter Embolization and Femoro-femoral Bypass :
A Case Report

Department of Radiology, Gynecology1), and Urology2),
National Hospital Organization Osaka National Hospital
Atsushi Nakamoto, Keiko Kuriyama, Takashi Haneda, Yukiko Tokuda, Soomi Choi,
Hisanori Matsumoto1), Chiaki Ban1), Toru Takahashi2), Toshitsugu Oka2)
Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine
Keigo Osuga

A woman in her sixties was referred to our hospital for macrohematuria and right flank pain. She had undergone pelvic surgery for cervical cancer of the uterus followed by external irradiation five years earlier. Subsequently, bilateral ureteral tube stents had been placed for hydronephrosis. Pelvic angiography demonstrated a large pseudoaneurysm of the right external iliac artery, and CT during arteriography demonstrated that the right ureteral stent passed through the pseudoaneurysm. Transcatheter coil embolization to the pseudoaneurysm and femoro-femoral bypass surgery were performed under local anesthesia on the same day, and hematuria was relieved subsequently. To date, the patient has remained well without complications for 9 months after therapy.

Key words
● Arterio-ureteral fistula
● Pseudoaneurysm
● Transcatheter arterial embolization

Case Report
New Approach of BRTO Using a Micro-balloon Catheter :
A Case Report

Department of Radiology, Third Department of Internal Medicine1), Asahikawa Medical College
Michihiro Nakayama, Koji Takahashi, Tomonori Yamada, Kenichi Nagasawa,
Hatsune Hiranuma, Akihiro Sakuma, Tomoaki Sasaki, Nobuhisa Takada,
Eriko Takabayashi, Tamio Aburano, Takaaki Otake1)

Balloon-occluded retrograde transvenous obliteration (BRTO) has been widely accepted as the standard treatment for gastric varices at many institutions in Japan. However, in cases with gastric varices accompanied by complex collateral veins, the standard BRTO might be technically difficult. In these cases, additional techniques, including coil embolization of collateral vessels and selective injection of agent into varices via a micro catheter, are required for successful treatment.
We report a case of successful BRTO for treatment of gastric varices with a micro-balloon catheter in which we could properly advance the micro-balloon catheter beyond complex collateral vessels and selectively inject the agent into the varices.
To the best of our knowledge, this is the first case of BRTO using a micro-balloon catheter.

Key words
● Micro-balloon catheter
● Gastric varices

Technical Note
The Size Distribution of Porous Gelatin Particles (GelpartR)
Department of Radiology, Saiseikai Shiga Hospital
Tetsuya Katsumori

Objective : To assess the size distribution of porous gelatin particles (GelpartR).
Materials and Methods : GelpartR labeled as 1mm and 2mm in size was separately poured into empty laboratory dishes from each ample. Saline solution with a small volume of indigocarmine was added. The shorter length of GelpartR was measured using high-resolution photographs of the laboratory dishes and the size distribution of each sample was evaluated.
Results : One hundred sixteen of 160 GelpartR particles (69%) labeled as 1mm ranged between 800~1200um in size. Twenty-seven of 116 GelpartR particles (17%) labeled as 2mm ranged between 1800~2200um in size.
Conclusion : GelpartR has marked unevenness in its size distribution.

Key words
● Porous gelatin particles
● Size
● Embolic agent