IVR 会誌 Jpn J Intervent Radiol Vol.17 No.2 2002

State of the Art
Metallic stent I. Vascular-its basic theory and current development-

Basic Theory of Vascular Stents and Recent Stent Technology
Department of Diagnostic Radiology, Keio University School of Medicine
Terumitsu Hasebe, Subaru Hashimoto, Seishi Nakatsuka, Kazuhiro Matsumoto, Sachio Kuribayashi
Department of Thoracic-Cardiovascular Surgery, Kitasato University School of Medicine
Atsushi Shimada, Hirokuni Yoshimura

In-stent restenosis remains the major limitation of vascular stenting. Restenosis is related to patient-, lesion, and procedure-specific factors. Procedure-specific factors are affected by interventional technique and stent characteristics. Design and material influence vascular injury and cellular response. Next to optimizing stent properties and profile, stent materials and coating have been recently investigated to improve hemocompatibility and tissue compatibility(biocompatibility). This is even more important because it has become clear that treatment of restenosis and especially in-stent restenosis still has poor results, and the best way to diminish these refractory restenotic lesions is their prevention.
One of the problems of vascular stenting is the thrombogenecity of stent metal itself. In situ thrombus formation sets the stage for the temporal cascade of molecular and cellular reactions that cause extracellular matrix deposition by modified smooth muscle cells and remodeling. All currently available stents are composed of metal. The most recent available stents are manufactured of SUS316L stainless steel. Future stents should be made less thrombogenic and more biocompatible by modifying the metallic surface, or coating it with antithrombotic and/or antiproliferative agents or a membrane eluting antithrombotic and/or antiproliferative drugs. Another approach is to make stents of biodegradable materials as an alternative to metallic stents. Ongoing clinical trials with new stent technology may introduce a new era of improvement.
Key words
● Metallic stent
● Stent materials & coating
● Biocompatibility

2.Aortic Stent-Graft
Department of Diagnostic Radiology, Tokai University School of Medicine
Jun Koizumi

Since the first clinical implant of a tube graft in 1990 by Parodi et al, many different stent-graft designs have been developed and are commercially available outside of Japan. More than 3,000 patients have been registered in EUROSTAR, and the indication for aortic dissection tends to be another concern. This article reviewed the feasibility and efficacy trial of an endovascular stent-grafting system for the treatment of aortic aneurysms in foreign countries and reported the semi-homemade system available in Japan. Technical success rate is very high and the short to middle term mortality and morbidity are acceptable considering the high risk character of the candidates as compared with open surgery. The best way to avoid initial endoleaks is to stick to the anatomic inclusion criteria. However the late development of endoleaks is a significant concern. Thus stent-graft repair may be recommended for the elderly and those at high risk for open surgical procedures. Second-generation devices should allow improved clinical results and expand the indications after careful trials in the future.
Key words
● Aorta
● Stent-graft
● Endoleak

3.Stenting Placement for Peripheral Arterial Disease
Department of Radiology, Kumamoto University School of Medicine
Yukunori Korogi, Yoshinori Shigematsu, Mika Kitajima

Stenting and balloon PTA are safe and successful treatment options for peripheral arterial diseases, and are now considered as the treatment of choice for lifestyle-limiting intermittent claudication caused by iliac artery occlusive disease. Primary stenting is effective for occlusions, restenoses after PTA and complicated severe stenoses in the cases with iliac arterial disease. Angioplasty followed by selective stent placement seems more feasible than a primary placement of a stent for the"simple"stenotic lesions, since angioplasty followed by selective stent placement is less expensive than the direct placement of a stent, and no substantial differences between the two treatment strategies(primary stenting or selective stenting) have been observed in the technical results or clinical outcomes both at short-term and long-term follow-up. PTA with selective stent placement is a cost-effective treatment strategy compared with primary stent placement or PTA alone in the treatment of intermittent claudication caused by an iliac arterial stenosis. Stenting is less feasible for infra-inguinal arterial lesions, because the long-term results of stenting are not better than those of PTA in spite of its good short-term results.
Key words
● Stent
● Transluminal angioplasty
● Arteriosclerosis

4.Superior Vena Cava Stent
Department of Radiology, Saiseikai Central Hospita
Tsuneyuki Takashina, Kenichi Kodera

Superior vena cava syndrome(SVCS) is a very uncomfortable manifestation of intrathoracic malignancies, mediastinal fibrosis, and other diseases. Treatment with percutaneous metallic stent placement into the superior vena cava(SVC) has been used with success to relieve obstruction to blood flow quickly. We present several cases of patients with severe SVCS who underwent successful treatment with placement of Gianturco Z-stent. We also review published reports on the use of stents for SVCS. Results from reported experiences demonstrate that metallic stents are effective for treatment of SVCS, offering immediate relief of symptoms. Also, the radiological findings are useful for prediction of clinical outcome. In our cases, recurrence of SVCS occurred in 35%. In the patients who had recurrence, the SVC lumen was obstructed due to tumor ingrowth and thrombosis. Our result suggests that use of antithrombotic therapy is important for long-term stent patency.
Key words
● Superior vena cava syndrome
● Metallic stent
● Antithrombotic therapy

5.Coronary Stenting, Progress in the Treatment of Ischemic Heart Disease
Department of Cardiology, Kokura Memorial Hospital
Yoshihisa Nakagawa, Masakiyo Nobuyoshi

Stents have become the most important advance in mechanical techniques for percutaneous coronary intervention(PCI). Stents have the common goal of enlarging the vascular lumen and decrease the incidence of restenosis. Restenosis remains a vexing problem of stent implantation, especially in the treatment of small size vessels. Intracoronary radiation has been introduced as a new approach to prevent restenosis, but some relevant side effects, edge restenosis and late thrombosis, has been reported. The implantation of sirolimus-eluting stent is the most promising approach to overcome restenosis. Recent report demonstrates a sustained suppression of neointimal proliferation by sirolimus-eluting stent 1 year after implantation.
Key words
● Coronary artery disease
● Stent
● Drug-eluting stent

Original Article
Artifacts of Metallic Stents on Contrast Enhanced 3D MR Angiography : Experimental and Clinical Studies
Department of Radiology, Showa University Fujigaoka Hospital
Minoru Honda, Masao Obuchi, Hayato Kubota, Takaki Hayashi, Wakako Yamamoto, Hideharu Sugimoto
Department of Internal Medicine, Yokohama Shinmidori General Hospital
Kazuhiko Sekiyama

Purpose : To evaluate artifacts of metallic stents on contrast enhanced 3D MR angiography (MRA), we performed the following experimental and clinical studies.
Materials and Methods : For the experimental study, each of four types of Wallstents, four types of Palmaz stents and four nitinol stents(Accuflex, Memotherm, ZA-stent, SMART) was inserted into acrylic tubes(10a in diameter, 20b in length). Gd-DTPA was poured into each tube at a concentration of 1/500, and the tubes were placed in a container filled with water. For the clinical study, biliary and vascular stents(1 old biliary Wallstent, 1 new biliary Wallstent, 1 Easy Wallstent, 1 ZA-stent, 1 Palmaz-Corinthian, 6 Accuflex, 4 SMART) were placed in ten patients treated with TIPS(transjugular intrahepatic portosystemic shunt). We observed artifacts and the intraluminal signal intensity of each stent on MRA.
Results : Large artifacts were observed beyond the sides of the tubes containing the large and medium Palmaz stents. Intraluminal signal intensity of the nitinol stents, old biliary and vascular Wallstent, long-medium Palmaz and Palmaz-Corinthian stent was visible on MRA.
Conclusion : To reduce the size of artifacts and observe the intraluminal signal intensity on MRA, stents made of nitinol or Elgiloy with large mesh should be used
Key words
 ●Stents and prostheses
 ●Magnetic resonance(MR)

Case Report
Percutaneous Sacuroplasty with Calcium Phosphate Bone Paste Injection as a New Treatment for Sacral Metastases from Renal Cell Carcinoma : A Case Report
Departments of Radiology and Urology1), Oita Red Cross Hospital
Shinichiro Ueno, Yoshiharu Imagawa1)
Department of Radiology, Oita Medical University
Norio Hongo, Kunihiro Asai Rieko Shuto, Shunro Matsumoto, Hiromu Mori

A 69-year-old man with renal cell carcinoma and with multiple metastases to the lymph nodes and bones was admitted to our hospital because of buttock pain. Percutaneous injection of Methyl-methacrylate bone cement was excluded from the treatment options for sacral metastases because the polymerisation can cause heat injury to the adjacent sacral nerve. Thus, We chose Calcium-phosphate bone paste, which lacks a thermogenic reaction, as the material to be injected into the sacral metastases. Pain relief was satisfactorily obtained without complications. Direct injection of Calcium-phosphate bone paste is thought to be effective in treating bone metastases neighboring the nerve.
Key words
 ●Calcium-phosphate bone paste
 ●Percutaneous bone plast
 ●Surgical bone cement

Case Report
Covered Stent in the Treatment of Common Iliac Artery-Ureteral Fistula : A Case Report
Departments of Radiology1) and Urology4), Tokyo Woman’s Medical University Third
Department of Surgery2), Tokyo Medical University
Department of Radiology3), Sent Marianna Medical University

Yoshihiro Yasuda1,2), Eigoro Yamanouchi1,3), Reiko Kumano1,3), Mio Ueda1), Fumikazu Sakai1), Kazunari Tanabe4), Ko Toma4), Akihiko Tsuchida2), Tatsuya Aoki2), Yasuhisa Koyanagi2)

A 69-year-old woman, who received extended hysterectomy because of cervical cancer and had an urinary stent due to ureter stenosis after operation and radiotherapy, was admitted to our hospital complaining of hematuria. During her stay she had a recurrence of massive hematuria. An ureteroarterial fistula was detected by emergency angiography. We were successful in placing a covered stent(Passager stent graft, Boston Scientific, USA) into the right common iliac artery. There have been only 20 reports of ureteroarterial fistula, and our case is the first in placing a stent through a catheter from the femoral artery.
Key words
 ●Ureteroarterial fistula
 ●Covered stent

Case Report
Embolization of the Common Hepatic Artery Using COMMODORETM before Radical Pancreatectomy with Celiac Arterial Resection
Department of Radiology and First Surgery1), Sapporo Medical University
Takeshi Ichimura, Kazumitsu Koito, Naoki Hirokawa, Hideki Hyodoh, Takaharu Shonai, Kensei Nakata, Masato Hareyama, Tomohisa Furuhata1), Mitsuhiro Mukaiya1), Koichi Hirata1)

We report a case of common hepatic arterial embolization using a temporary occlusion balloon micro-catheter COMMODORETM, in order to obtain sufficient blood supply from the gastroduodenal artery after Appleby’s operation.
We could perform coil embolization precisely with ease and safe. Our method is considered to be suitable for various vessel occlusions without anchor coil.
Key words
 ●Arterial embolization
 ●Balloon micro-catheter
 ●Appleby’s operation

Case Report
A Case of Hepatocellular Carcinoma, Fed by the Right Inferior Adrenal Artery, Effectively Managed by a Catheter with a Large Side Hole for Selective Catheterization
Departments of Diagnostic Radiology and Surgery1), Maizuru Kyosai Hospital
Tatsuya Yamamoto, Norio Takahashi, Hideaki Nezuka1), Yoshiaki Isobe1)
Department of Diagnostic Radiology, Fukuiken Saiseikai Hospital
Shiro Miyayama

We report a case of hepatocellular carcinoma(HCC), fed by the right inferior adrenal artery (IAA), effectively managed by a catheter with a large side hole for selective catheterization. The patient was a 69-year-old woman with recurrent HCC fed by the right IAA, which could not be selectively catheterized by a conventional coaxial technique. A hole formed in the side wall of the superior portion near the tip of the 5-F catheter, inserted into the right renal artery, enabled us to treat the tumor by introducing a microcatheter into the right IAA via the hole.
Key words
 ●Transcatheter arterial embolization
 ●Side hole

Technical Note
Modification of Reversing the Flared End of the Ultraflex for Use in the Colon
Departments of Diagnostic Radiology, Surgery1), and Obstetrics and Gynecology2)
Fukuiken Saiseikai Hospital

Shiro Miyayama, Yukari Akakura, Toru Yamamoto, Hiroto Nishida, Kenji Yoneda, Keiichi Kawai, Hideo Saito1), Yoshiro Iida1), Kumiko Hosokawa2)

We report the usefulness of modification of reversing the flared end of the uncovered Ultraflex for use in the colon. The unexpanded Ultraflex with a distal release system was separated from the delivery catheter, and then put on the shortened delivery catheter upside down. The several ties of the crocheted suture cord were untied, and the trailing end of the stent was pushed up until short enough to enter the rectum. The modified delivery system was used in two patients with inoperable malignant rectal stricture. The stent was placed accurately without any difficulty, and functioned well in both patients.
Key words
 ●Malignant colorectal stricture
 ●Colon, interventional procedure
 ●Colon, stent and prosthesis

Technical Note
Value of CT-Guided Hookwire Placement : Analysis of Malpositioned Hookwire
Department of Radiology and SurgeryII 1), Akita University School of Medicine
Yoshinori Hirano, Manabu Hashimoto, Toshimasa Nishii, Etuko Tate,, Kohichi Oomachi, Kohichi Ishiyama, Jiroh Watarai, Hajime Saitou1), Yoshihiro Minamiya1), Jyunichi Ogawa1)

Percutaneous localization of 39 lung nodules with the hookwire was performed in 38 patients under CT guidance. This technique was easily performed and provide a reliable alternative to nodule localization prior to thoracoscopic resection in 34 nodules(87%). We could not place the hookwire in the designed portion in 5 nodules; hookwire was inadvertently cross the fissure and placed neighbor lobe in 2 nodules, the localization wire became dislodged from the lung parenchyma by the time thoracoscopy in 2, the suture was broken in 1.
Key words
 ●CT guided