IVR 会誌 Jpn J Intervent Radiol Vol.17 No.3 2002

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

1.Metallic Stent Intervention for Unresectable Malignant Biliary Obstruction
Departments of Surgery and Radiology1), Ohtawara Red Cross Hospital
Junichi Matsui, Tetsu Amemiya, Kimiyoshi Mizunuma1)
Department of Surgery, Tochigi Cancer Center
Moriaki Tomikawa, Iwao Ozawa, Shoichi Hishinuma

The history and new variations of biliary metallic stents are summarized briefly. We have treated 68 patients that had unresectable malignant biliary obstructions, with many types of biliary metallic stent, during the period from 1991 to 2001. We conclude from this experience that the metallic stent has clinical benefits, as its application can enhance the QOL of the patients and has the potential to prolong the survival time with use of radiotherapy and/or chemotherapy. In the case of an unresectable gallbladder or pancreas carcinoma whose prognosis is estimated to be shorter than two months, however, application of the metallic stent should be considered contraindicated. The postmortem examinations reveal high rates of biliary sludge formation, inflammatory granulation and disepitheliarization along the non-tumor bile duct with stent placed, and choledocho-duodenal fistula. We need in the near future new ideal technologies to
prevent tumor ingrowth and overgrowth, and newly-devised materials of metallic stent that can decrease its disturbance to bile duct epithelium and reduce stagnation and sludge formation of bile. The covered stent could be a solution to overcome these issues.
Key words
● Biliary malignancy
● Obstructive jaundice
● Metallic stent
● Covered stent

2.Metallic Stent for Airway Stenosis
Department of Thoracic Surgery, Saiseikai Central Hospital
Hiroaki Nomori

The basis and clinical applications of metallic stent for airway stenosis are demonstrated. Metallic stent has the following advantages : (1) it can be inserted through an endotracheal tube under local anesthesia, and (2) it does not impair the drainage of sputum because ciliary movement is not interrupted. However, its disadvantages are as follows : (1) it is not effective for tracheobronchial stenosis due to intraluminal tumor invasion or granulation tissue because the tumor or granulation tissue can grow between the wires and (2) after placement, it can not be removed. The problem of growth of tumor or granulation tissue between the wires can now be solved by the recent"Covered Ultraflex". However, these covered metallic stents have a risk of infection between the stent and airway mucosa. If infection occurs, the covered metallic stent can never be removed, which is the critical disadvantage. For the patient with severe tracheal stenosis, bougienage and balloon dilation using a tracheal tube with an integral cuff via a tracheostomy is a simple and safe method for achieving both urgent relief of airway stenosis and dilation before stent placement. Sufficient knowledge of the advantages and disadvantages of metallic stents is required for their proper use.
Key words
● Airway stenosis
● Stent
● Lung cancer

3.Metallic Stents in the Esophagus and Gastrointestinal Tract
Department of Radiology, Hoshigaoka Kouseinenkin Hospital
Takehiro Tanaka
Department of Radiology and Oncoradiology, Nara Medical University
Kimihiko Kichikawa, Hiroshi Sakaguchi, Takahiro Ito, Yoshihiro Matsuo, Hajime Ohishi
Department of Radiology, Nara Prefectural Nara Hospital
Tetsuya Yoshioka

Metallic stents have been used for inoperable esophageal strictures and esophagorespiratory fistulas for more than ten years. These stents are safe and effective for improvement of symptoms and widely used.
Following successful results in esophagus, application of metallic stents has been expanded to colorectal, duodenal, gastric and benign strictures. In colorectal strictures the stents are placed temporarily or permanently. Temporary use is a preoperative treatment, which relieves acute colorectal obstruction and allows a safe single-stage surgery. Permanent use is a palliative treatment for inoperable colorectal malignancies in order to avoid colostomy. The gastric outlet obstruction syndrome caused by malignant obstruction of the gastric antrum or duodenum is treated by a metallic stent. This article deals with basic and recent advances in metallic stents for strictures of esophagus, stomach, duodenum, and colon.
Key words
● Stents and prostheses
● Interventional procedure
● Esophagus, stenosis or obstruction
● Intestines, stenosis or obstruction

Metallic stent I. Vascular-its basic theory and current development-
6.Current Status of Carotid Artery Stenting
Departement of Neurosurgery, Kobe City General Hospital
Nobuyuki Sakai, Terumasa Kuroiwa, Chiaki Mikami, Hiroshi Manaka, Hirotoshi Imamura, Hidemitsu Adachi, Shuichi Kobayashi, Satoshi Nakao, Izumi Nagata, Waro Taki, Haruhiko Kikuchi

Carotid artery stenting(CAS) has been developed in recent years as an alternative to carotid endarterectomy(CEA). We report our clinical experience of CAS and evaluate the feasibility and efficacy of this treatment. Since 1997 Feb, 237 patients(199 male, aged 50~85, mean 67.5),235 carotid artery stenosis (109 symptomatic, 126 asymptomatic)procedures. 5 aortitis, 1 FMD, and 6 dissection were treated with 259 endovascular stenting. Our method in now is as follows; under local anesthesia, transfemoral approach, using 9F guiding catheter, pre-dilation with low profile 3.0~3.5a PTA balloon with 0.014" long wire, and self-expandable stent(Easy Wallstent, SMART stent, AccuLink-II) deployment. Since 1998 Dec, we have used our originally made distal balloon protective system in post PTA. Embolic events were checked by TCD, MRI/DWI and histopathological study by aspirated blood.
Procedural success was 99.2%, and complication occurred in 2(0.77%) major and 6(2.3%) minor stroke without mortality. However, embolic signals and debri were detected in all cases with TCD and histopathological study, and procedure related ischemic lesions were detected by MRI/DWI study in about 50% of cases. Restenosis occurred in 12/155(7.7%) of F/U angiography, 6~50 months after treatment. No complication occurred in re-treatment.
Conclusions : Our results indicate that carotid stenting may well offer a similar safety profile and efficacy to those of carotid endarterectomy. The future status of carotid artery stenting will be determined with randomized trials and improvement in devices, technique and safety.
Key words
● Carotid artery
● Stent
● Protection

Original Article
Development of Biodegradable Stent for Gastrointestinal Tract
Department of Radiology, Shiga University of Medical Science
Toyohiko Tanaka, Akira Furukawa, Norihisa Nitta, Michio Yamasaki, Masashi Takahashi, Kiyoshi Murata
Department of Radiology, Kohga Public Hospital
Tsutomu Sakamoto, Katsuji Imoto
Medico’s Hirata Inc.
Toru Yokogawa, Hajime Sakai

Purpose : To evaluate the characteristics of newly developed biodegradable stent for benign stenosis of the gastrointestinal tract.
Materials and methods : We developed a biodegradable stent constructed of knitting polylactic acid monofilament in a zig-zag shape. Used device system was composed of four stents with six bends each. The diameter and length were 15a and 12a respectively. Strength of the stent was evaluated by measuring the force required to change the diameter ; defined as pressure to change the diameter of the stent in 5a divided by the length of the pressed segment along the stent axis(n/a/b). The expansive forces were compared among biodegradable stent, metallic Z stent and metallic spiral Z stent. In addition, the influence on the expansive force of different PH conditions was also evaluated.
Result : The expansive force of the biodegradable stents was 21n/a/b and larger than those of metallic Z stent(14n/a/b)and metallic spiral Z stent(7n/a/b). The expansive force was not significantly influenced by immersion into various PH solutions with one month observation. However, slight loss of the force was noted at alkalic state with three months observarion. On six months observation, the stents in all kinds of solution showed loss of the expansive force.
Conclusion : Newly developed biodegradable stents were proved to have sufficient expansive force to dilate gastrointestinal stenosis. This stent has the possibility of application for the alimentary tract
Key words
 ●Biodegradable stent
 ●Gastrointestinal tract
 ●Benign lesion

Case Report
Massive Bleeding from Giant Anorectal Varices due to Altered Portal Venous Flow in a Patient with Primary Biliary Cirrhosis
Center for Digestive and Liver Diseases, Department of Diagnostic Imaging1), Ofuna Chuo Hospital
Kentaro Takatsuka, Shogo Iwabuchi, Akihiro Murayama, Takashi Ito,
Hiroyuki Ide, Fumiaki Ueno, Tomikazu Mizuno1)
Department of Surgery, St. Marianna University Yokohama City Seibu Hospital
Masaru Hagiwara

We report a rare case of anorectal varices associated with primary biliary cirrhosis(PBC). A 70-year-old female was admitted for massive rectal bleeding. One year prior to admission, she was treated for ruptured esophageal varices by endoscopic variceal ligation(EVL). The superior mesenteric angiogram demonstrated a dilated inferior mesenteric vein(IMV) with hepatofugal flow, with filling giant rectal varices and draining into the inferior vena cava(IVC) through the bilateral iliac veins. However, the splenic angiogram showed hepatopetal flow of the splenic vein without varix formation. The superior mesenteric arteriogram under balloon occlusion of the splenic vein, revealed an opacified portal vein from the superior mesenteric vein.
She underwent percutaneous transhepatic obliteration(PTO) of anorectal varices as well as splenectomy for splenomegaly. The follow-up period of 12 months shows no recurrence of varices and improved liver function.
Key words
 ●Anorectal varices
 ●Portal hypertension
 ●Percutaneous transhepatic obliteration(PTO)

Case Report
Acute Type A Aortic Dissection Complicated by Aortic Rupture
-A Case which was Successfully Treated with Endovascular Stent-graft Placement-
Departments of Radiology, and Thoracic and Cardiovascular Surgery1), Mie University Hospital
Shao Hua Cheng, Noriyuki Kato, Takatsugu Shimono1), Masaki Ishida, Isao Yada1), Kan Takeda
Department of Radiology, Matsusaka General Hospital
Tadanori Hirano

A70-year-old man with acute type A aortic dissection, which was complicated by aortic rupture into the mediastinum, underwent endovascular stent-graft placement to close the entry tear. Although respiratory failure and left arm ischemia developed postoperatively, both were treated successfully. He has been doing well for a year without any complications. Entry closure with endovascular stent-graft placement may be an effective alternative to surgical intervention for the treatment of complicated aortic dissection in limited cases.
Key words
●Aortic dissection
●Stents and prostheses
●Aortic rupture

Technical Note
Modification of the Preloading Delivery System for Use in Stent-graft Placement
Departments of Diagnostic Radiology and Vascular Surgery1), Fukuiken Saiseikai Hospital
Shiro Miyayama, Yukari Akakura, Toru Yamamoto, Hiroto Nishida, Kenji Yoneda, Keiichi Kawai, Shinya Murakami1)

We report the usefulness of a modified preloading delivery system for use in stent-graft placement. An 18-or 20-F long sheath was cut to the desired length, and the trailing end was widened with heat. A stop-cock valve made by another company was added, and then a modified preloading dilator with a coaxial attachment 2-F larger in diameter than the pusher was combined. This modified delivery system was used in 10 patients with abdominal aortic aneurysm. The stent-graft was successfully placed in all patients and there were no problems related to the delivery system observed.
Key words
 ●Aortic aneurysm
 ●Delivery system

Technical Note
A New Technique of Folding Back the Catheter Tip for Hepatic Intraarterial Infusion Catheter Placement
Department of Radiology, Ayabe Municipal Hospital
Hiroyuki Morishita, Hiromi Takegi
Deapartments of Radiology and Surgery1), Kyoto First Red-Cross Hospital
Yoshito Takeuchi, Takanobu Suzuki, Keitarou Kan1)
Department of Radiology, Kyoto Prefectural University of Medicine
Takuji Yamagami, Takeharu Katou, Osamu Tanaka

We described a new technique of folding back the catheter tip for hepatic intraarterial infusion chemotherapy.
A double side holed catheter tip was folded back with the splenic artery and its folded tip was inserted into the gastroduodenal artery. The special catheterization was successful in 13 of 14 cases. The technique reduced the number of coils or cyanoacrylate needed to occlude the gastroduodenal arterial flow, because the folded catheter tip worked not only as an embolization material but also as an anchor.
We concluded that the technique of folding back the catheter tip is easy and useful for hepatic arterial infusion chemotherapy.
Key words
 ●Catheter placement
 ●Folding back method
 ●Arterial infusion chemotherapy