Modifications of Gianturco expandable wire stents.
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Animals↗
Biomedical subjects
B T Uchida
Publications and source records attributed to B T Uchida.
Modified Gianturco expandable wire stents in experimental and clinical use.
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Angioplasty, Balloon↗
Diagnosis and treatment of fallopian tube obstruction with selective salpingography and catheter recanalization.
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Adolescent↗
Diagnosis of cornual obstruction by transcervical fallopian tube cannulation.
Interstitial fallopian tube obstruction (IFTO) occurs in 15% of hysterosalpingograms (HSG) performed for infertility. Conventional HSG or laparoscopy may not differentiate cornual spasm or other temporary cause from true obstruction. We used transcervical cannulation of the proximal oviduct with a 3-F Teflon catheter and flexible guidewire 0.018 inch (0.043 cm) in diameter under hysteroscopic or fluoroscopic guidance to evaluate IFTO in 28 patients. Fluoroscopic catheterization techniques with selective salpingography demonstrated patency in 84% of obstructed tubes. Hysteroscopic cannulation with direct visualization by laparoscopy or laparotomy was successful in 92%. In one patient, perforation of the isthmus occurred without sequelae. Transcervical coaxial cannulation of the proximal oviduct is an effective method for evaluating cornual obstruction.
Adult↗
Experimental intrahepatic portacaval anastomosis: use of expandable Gianturco stents.
Original Gianturco expandable stents and their modifications were used to create an experimental intrahepatic portacaval anastomosis (EIPCA) in 30 young domestic swine without portal hypertension. The study focused on the design of a suitable stent, the technique of its application, and the evaluation of short-term patency of the EIPCA. A stent with a 2.5-cm-long body and wire skirts on both ends was most suitable for EIPCA creation. Well-positioned stents shunted most of the portal blood in the inferior vena cava circulation and remained patent for 4-6 weeks. Ingrowth of liver parenchyma and abundant proliferation of the intima and connective tissue inside the stent lumen in these rapidly growing animals gradually decreased EIPCA patency, and thrombus formation with diminished blood flow closed them completely.
Animals↗
Fallopian tube obstruction: selective salpingography and recanalization. Work in progress.
Seven infertile women, in whom interstitial fallopian tube obstruction (IFTO) was suspected at hysterosalpingography and who were recommended for surgical evaluation and treatment, were treated with catheterization techniques. Selective salpingography with ostial injection demonstrated tubal patency in two patients; direct intratubal salpingography demonstrated patency in another patient. Four patients with a true IFTO underwent fallopian tube recanalization: in the first two, a small soft-tipped guide wire was used, and in the other two, a guide wire and 3-F catheter were used. The suggested catheterization techniques have the potential to make evaluation and treatment of IFTO more efficient, safer, and less expensive than presently used methods.
Adult↗
"Atraumatic" transjugular needle for portal vein puncture in swine.
A new coaxial needle-catheter system was designed for transjugular portal vein puncture in young domestic swine. It was tested in 32 animals and successfully entered the portal circulation via a hepatic vein or intrahepatic portion of the inferior vena cava. No complications were encountered.
Animals↗
Gianturco-Rösch expandable Z-stents in the treatment of superior vena cava syndrome.
Gianturco-Rösch expandable Z-stents were used in 22 patients with superior vena cava syndrome (SVCS). Stents were placed in all patients in the SVC and in 17 patients, also into the innominate veins. Stent placement resulted in complete relief of symptoms in all patients. Twenty-one patients had no SVCS recurrence from 1 to 16 months, to their death, or to the present time. SVCS recurred only in 1 patient 9 months after stent placement due to tumor ingrowth and secondary thrombosis. Based on ours and on other reported experiences, expandable metallic stents are effective devices for treatment of the SVCS which is difficult to manage by other means.
Brachiocephalic Veins↗
Multi-site interventional real-time procedure demonstrations with the use of integrated services digital network connections.
PURPOSE: To evaluate the effectiveness and cost of commercially available video conferencing units and standard Integrated Services Digital Network (ISDN) connections for real-time multi-site transmissions of interventional procedures. METHODS: A network of five separate interventional radiology departments-three in the Czech Republic and one each in Austria and the USA-was established using Polyspan (Polycom in the USA) View Stations and ISDN connections. This network was used for transmissions of 16 live interventional procedures to the Sixth International Workshop on Interventional Radiology in Prague, Czech Republic in June 2000. RESULTS: The transmissions were successful and of sufficient quality to contribute to the educational success of the workshop. The cost of the ISDN transmissions was a fraction of satellite transmission costs. CONCLUSION: Multi-site real-time interventional procedure transmissions using video conferencing Polyspan (Polycom) View Stations and ISDN connections are a promising means of improving interventional tele-education and decreasing its cost.
Austria↗
Endoluminal treatment of ruptured abdominal aortic aneurysm with small intestinal submucosa sandwich endografts: a pilot study in sheep.
PURPOSE: To evaluate efficacy of small intestinal submucosa (SIS) Sandwich endografts for the treatment of acute rupture of abdominal aortic aneurysms (AAA) and to explore the short-term reaction of the aorta to this material. METHODS: In eight adult sheep, an infrarenal AAA was created transluminally by dilation of a short Palmaz stent. In six sheep, the aneurysm was then ruptured by overdilation of the stent with a large angioplasty balloon. Two sheep with AAAs that were not ruptured served as controls. A SIS Sandwich endograft, consisting of a Z stent frame with 5 bodies and covered inside and out with SIS, was used to exclude the ruptured and non-ruptured AAAs. Follow-up aortography was done immediately after the procedure and before sacrifice at 4, 8, or 12 weeks. Autopsy and histologic studies followed. RESULTS: Endograft placement was successful in all eight sheep. Both ruptured and non-ruptured AAAs were successfully excluded. Three animals with AAA rupture developed hind leg paralysis due to compromise of the arterial supply to the lower spinal cord and were sacrificed 1 day after the procedure. In five animals, three with rupture and two controls, follow-up aortograms revealed no aortic stenoses and no perigraft leaks. Gross and histologic studies revealed incorporation of the endografts into the aortic wall with replacement of SIS by dense neointima that was completely endothelialized in areas where the endograft was in direct contact with the aortic wall. In central portions of the endograft, in contact with the thrombosed aneurysm, endothelialization was incomplete even at 12 weeks. CONCLUSION: The SIS Sandwich endografts effectively excluded simple AAAs and ruptured AAAs. They were rapidly incorporated into the aortic wall. A detailed long-term study is warranted.
Angioplasty↗
Experimental TIPS with spiral Z-stents in swine with and without induced portal hypertension.
PURPOSE: To assess the suitability of spiral Z-stents for transjugular intrahepatic portosystemic shunt (TIPS) and the influence of portal hypertension on shunt patency in young swine. METHODS: TIPS were established using spiral Z-stents in 14 domestic swine. In 7 animals, the portal venous pressure was normal; in the other 7, acute portal hypertension was induced by embolization of portal vein branches. Follow-up portal venography and histologic evaluations were done from 1 hr to 12 weeks after TIPS. RESULTS: Follow-up transhepatic portal venograms showed progressive narrowing of the shunt, most prominent in the midportion of the tract. Ingrowth of liver parenchyma between the stent wires found after 3 weeks led to progressive shunt narrowing and shunt occlusion by 12 weeks. A pseudointima grew rapidly inside the stent, peaked in thickness around 4 weeks, and decreased later. Acutely created portal hypertension rapidly returned to normal and there was no difference in TIPS patency between the two groups of animals. CONCLUSION: Although the spiral Z-stent can be used as a device for creation of TIPS in patients with cirrhotic livers, it is associated with extensive liver ingrowth in swine that leads to rapid shunt occlusion. Portal hypertension was only transient in this model.
Animals↗
Polyurethane-coated Dacron-covered stent-grafts for TIPS: results in swine.
PURPOSE: To evaluate shunt patency after placing a new polyurethane-coated Dacron-covered spiral Z stent-graft to create a transjugular intrahepatic portosystemic shunt (TIPS). METHODS: TIPS stent-grafts were placed in six young swine, using polyurethane-coated, Dacron-covered spiral Z stent-grafts. Animals were followed weekly by transhepatic portal venography until shunt occlusion or up to 6 weeks, then were sacrificed for gross and histologic evaluation. RESULTS: Five of six TIPS stent-grafts were found to be occluded by 3 weeks and none were patent at 6 weeks. Histologic evaluation demonstrated a marked foreign body reaction with superimposed thrombosis occluding the graft lumen. CONCLUSION: Polyurethane-coated Dacron-covered stent-grafts do not improve TIPS patency.
Animals↗
Retrievable IVC square stent filter: experimental study.
PURPOSE: In vitro and in vivo evaluation of a new retrievable, home-made, inferior vena cava (IVC) Square stent filter (SSF) with two trapping levels. METHODS: In vitro, the SSF was compared in a flow model with the stainless steel Greenfield filter (SGF) for emboli-trapping efficiency by serially passing 300 emboli of 3 and 6 mm in diameter and 15-30 mm in length in each type of filter. Nine swine were used for the in vivo testing of the SSF for deployment and retrievability, emboli-trapping efficiency, stability, and self-centering ability and two were used (total of 11 swine) for testing repositioning and retrievability of the SSF at 2 weeks and for gross and histologic IVC changes at 2 months. RESULTS: In vitro, the SSF and SGF had similar efficiency in trapping large emboli but the SSF had significantly better efficiency than the SGF for trapping all sizes of emboli (91.7% vs 81%), medium size emboli (93% vs 80%), and small emboli (86% vs 69%). Efficiency decreased in both filters from the first to the fifth embolus in each series but was still significantly better for the SSF. With the SSF, 89% of emboli were caught at the primary and 11% at the secondary filtration level. In the nine animals used for acute studies, the SSF was easily placed in all 27 attempts, assumed a central position 26 times, and was easily retrieved in 21 of 22 attempts. One tilted filter needed additional manipulation for retrieval. During emboli injection in five swine, the SSF had 97.2% emboli-trapping efficiency and demonstrated good stability. In the two animals used for longer-term evaluation, the filters were easily retrieved 2 weeks after implantation. Histologic evaluation at 2 months showed neointimal proliferation around the SSF wires in contact with the IVC wall, which was otherwise normal. CONCLUSION: The SSF is a promising filter. It is easy to place and retrieve, is stable after placement, and has high efficiency for trapping emboli. Promising results justify further experimental and eventual clinical studies with a commercially manufactured SSF.
Animals↗
Silicone-covered self-expanding metallic stents for the palliation of malignant esophageal obstruction and esophagorespiratory fistulas: experience in 32 patients and a review of the literature.
Esophagogastric malignancies often are manifested with progressive dysphagia or esophagorespiratory fistulas. Palliative modalities currently available have significant limitations. A modified Gianturco-Rösch silicone-covered self-expanding metallic Z stent was used in 32 consecutive patients with malignant esophageal obstruction (n = 24) or esophagorespiratory fistulas (n = 8). The stent was placed successfully in all patients. Dysphagia improved by at least two grades in 21 of the 24 patients (87.5%); the mean dysphagia grade fell from 3.21 to 1.08. Six of the 8 patients with fistulas were able to resume a normal diet, and the other 2 were able to eat solids without symptoms of aspiration. Complications occurred in 10/32 patients (31%) and included stent migration (4 patients), food impaction (2 patients), membrane disruption with tumor ingrowth (1 patient), tumor overgrowth (1 patient), early pressure necrosis with hemorrhage (1 patient), and late pressure necrosis with sepsis (1 patient). The latter 2 patients died, giving a mortality rate of 6.3%. Many complications were managed with endoscopic or interventional radiologic techniques. Although randomized prospective clinical trials are needed, the silicone-covered Gianturco-Rösch Z stent offers promise for the effective palliation of malignant esophageal obstruction and esophagorespiratory fistulas.
Adult↗
Small intestinal submucosa covered expandable Z stents for treatment of tracheal injury: an experimental pilot study in swine.
PURPOSE: To evaluate efficacy of small intestinal submucosa (SIS) as a stent covering in healing experimentally created tracheal defects and to explore the trachea's reaction to placement of SIS-covered stents. MATERIAL AND METHODS: A tracheal defect with a diameter of approximately 10 mm was created in six swine with use of a blade or electrocauterization. A double-body, self-expandable SIS-covered Gianturco Rösch Z stent was placed into the trachea to cover the defect. The animals were observed, and were killed when they developed respiratory problems. Autopsy and histologic studies were performed. RESULTS: The SIS-covered stents were accurately placed without immediate complications related to placement. All animals developed respiratory problems on follow-up. One animal died 9 days after procedure because of pneumonia, the others five were killed at 12, 17, 18, 28, and 56 days because of stridor, wheezing, and cough. At autopsy and histology, the tracheal defects were found to be completely healed, with epithelial lining and regeneration of submucosal glands. Animals whose defects were created with a blade demonstrated cartilage remodeling between 9 and 18 days, and apparent deposition of new cartilage at 28 days after SIS placement. The defects made by electrocauterization showed only fibrous tissue with no cartilage regeneration. The tracheal lumen was narrowed by overgrowth of granulation tissue, particularly at the end wires of the stents. In three animals, polypoid masses caused 60%, 70%, and 80% tracheal obstruction, respectively. CONCLUSION: Placement of SIS-covered stents contributed to rapid and effective healing of large tracheal defects. Rigidity and oversizing of Gianturco Rösch Z stents led to secondary changes of the tracheal wall, causing significant airway obstructions. Smaller size and flexible stents should be selected for future work.
Animals↗
Treatment of refractory benign biliary stenoses in liver transplant patients by placement and retrieval of a temporary stent-graft: work in progress.
PURPOSE: To evaluate patency of refractory benign biliary strictures in liver transplant patients treated with retrievable stent-grafts. MATERIALS AND METHODS: Eight male liver transplant patients who ranged in age from 42 to 52 years developed nine symptomatic biliary strictures (intrahepatic left duct, 1; hilar, 2; anastomotic, 6). These strictures had recurred despite multiple previous attempts of treatment (n = 33), including angioplasty (n = 27), surgery (n = 1), atherectomy (n = 1), metallic stent (n = 1), and prolonged catheter drainage (n = 3). As an alternative method of treatment for these refractory biliary strictures, transhepatic placement of expanded polytetrafluoroethylene stent-grafts across the strictures was performed through 10-F sheaths. In total, 14 stent-grafts were placed to treat the nine lesions, and nine of these stent-grafts were subsequently retrieved through 12-16-F sheaths. RESULTS: Stent-grafts were deployed successfully. Delayed migrations in two patients required additional stent-graft placement. One patient died of pneumonia 1 month after stent-graft placement; the remaining seven patients had stent-grafts successfully removed at 3-10 months (mean, 5.6 months). Nine intended stent-graft retrievals were performed successfully, with two requiring use of elongated forceps. Immediately after treatment, all strictures were widely patent. Five to 6 months after stent-graft removal in these seven patients, significant strictures recurred in four of eight lesions (50%). One patient underwent surgical revision. At 6-29 months (mean, 12 months) after stent-graft removal, the remaining six patients were without clinical or laboratory evidence of biliary obstruction, despite three patients with significant recurrent strictures. CONCLUSION: Temporary stent-graft placement for treatment of benign biliary strictures in liver transplant patients is technically feasible. Longer follow-up with larger patient series is necessary to assess effectiveness and possible broader applications.
Adult↗
Portal decompression after transjugular intrahepatic portosystemic shunt creation with use of a spiral Z stent.
PURPOSE: An experimental swine model of acute presinusoidal portal hypertension was used to investigate the feasibility of a spiral Z stent for transjugular intrahepatic portosystemic shunt (TIPS) placement and the correlation between the shunt (stent) size and degree of portal pressure decrease. MATERIALS AND METHODS: Twelve young swine were used. Acute portal hypertension was induced by means of selective injections of absolute alcohol, ethiodized oil, and polyvinyl alcohol sponge particles into intrahepatic portal branches. RESULTS: TIPS was successfully created in all swine by using spiral Z stents that were 6, 8, and 10 mm in diameter; each size stent was deployed in four animals. Being sufficiently flexible, spiral Z stents accommodated for curved shunt tracts. An average of 48% portal pressure decrease was achieved with 6-mm-diameter stents, 61% with 8-mm-diameter stents, and 87% with 10-mm-diameter stents. CONCLUSION: These results are in agreement with our clinical experience with use of Gianturco-Rösch Z stents for TIPS formation.
Animals↗
Coaxial catheter-needle system for transjugular portal vein entrance.
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Catheterization↗