A New Covered Biliary Metal Stent versus Uncovered Wallstent for Malignant Biliary Obstruction / 대한소화기내시경학회지

BACKGROUND/AIMS: In order to provide a complete obstacle to tumoral growth, we designed a new self-expandible metal stent fully covered with polyurethane membrane. The purpose of the study was to compare the safety and effectiveness of a new membrane-covered Niti-S stent versus conventional uncovered Wallstent. METHODS: In a prospective trial, 59 patients with malignant extrahepatic biliary obstruction received either a newly developed covered metal stent (Niti-S stent, 30 cases) or an uncovered metal stent (Wallstent, 29 cases) by the endoscopic transpapillary route. RESULTS: Effective biliary decompression was achieved in all patients initially, and short-term results were similar in both groups. Stent failure was observed in 4 of the 30 patients (13%) after a median period of 165 days in the Niti-S group and in 8 of the 29 patients (28%) after a median period of 152 days in the Wallstent group. The reasons of stent failure were occlusion (n=3) and migration (n=1) in the covered Niti-S stent group and occlusion (n=8) in uncovered Wallstent group. According to the Kaplan-Meier life table analysis, the patency rates after 90, 180, and 360 days were 100%, 90%, and 74% in covered Niti-S stent group and 100%, 73%, and 61% in uncovered Wallstent group respectively. The occluded membrane-covered Niti-S stent was easily removed endoscopically and a new Niti-S stent was reinserted in one patient. CONCLUSIONS: The new, membrane-covered Niti-S stent has a lower stent failure rate and a tendency toward long-term patency rate compared to uncovered Wallstent. The covering may effectively prevent tumor ingrowth and it is sometimes possible to remove an occluded Niti-S stent.

Insertion of Urethral Wallstent (MemothermR) at External Urethral Sphincter for the Treatment of Patients with Complicated Detrusor Sphincter Dyssynergia / 대한비뇨기과학회지

In patients with spinal cord injury, detrusor sphincter dyssynergia is a common and troublesome problem that may evoke progressive deterioration of upper urinary tract and urinary tract infection including sepsis. Instead of external sphincterotomy, urethral wallstent may be the useful treatment for the patients with detrusor sphincter dyssynergia refractory to conventional treatment. In addition, this method has some advantages of less invassive, less morbid and simpler technique than other treatment methods. We report our preliminary results of the urethral wallstent(MemothermR) for the treatment of 2 patients with complicated detrusor sphincter dyssynergia.

Coronary Stenting for Long Lesions:Comparison of Three Different Types of Stent

BACKGROUND: Coronary stenting is known to reduce the rates of restenosis in focal lesions, but the efficacy of stents for long lesions have not been thoroughly defined. To evaluate the immediate and follow-up results of three different types of stents in lesions longer than 20mm, consecutive series of patients (pts) were reviewed. METHODS: Between February 1996 and January 1997, 123 patients (male 68.3%, mean age 57+/-10 years) with a total of 130 lesions underwent long stent : stenting. Excluding multiple stents and unplanned use for acute closure fifty-three pts (56 lesions) were treated with the Microstent II (M-II):30 pts (31 lesions) received the Less Shortening Wallstent (WA):and 40 pts (43 lesions) were treated by the Gianturco-Roubin II stent (GR-II). RESULTS: With the clinical success defined as 50% diameter stenosis at FU was 26% in M-II, 32% in WA and 38% in GR-II:there was no significant difference between the three stents. Target lesion revascularization (TLR) defined as CABG or target lesion PTCA at FU was 17.6% in M-II, 12% in WA and 23.1% in GR-II. Restenosis rate correlated closely with lesion length (p-value-0.03, Odds ratio-1.096) and small post-stent luminal diameter (p-value-0.002, Odds ratio-0.063) in a mu-ltivariable analysis. CONCLUSION: Coronary stenting for long lesions can be safely performed with acceptable complication rates using any of the three types of stents. Restenosis and late outcome was not related to type of stent.

Reconstrução anatômica das artérias coronárias nativas e das pontes de safena utilizando Less Shortening Wallstent / Anatomic reconstruction of native coronary arteries and vein graft with the Less Shortening SelfÄExpandable Wallstent

OBJETIVO Ä Avaliar a utilizaçäo de apenas um stent, owallstent (WS), no tratamento de lesöes longas (LL) ou múltiplas (LM). MÉTODOS Ä Trinta e oito pacientes com idades variando de 42Ä82 (m=66) anos, sendo por cento do sexo masculino. Os vasos tratados foram: descendente anterior (14 pacientes); coronária direita (12); circunflexa (9) e pontes de safena (4). Cinco pacientes necessitaram de 2 stents: 4 PalmazÄSchatz no segmento proximal do vaso e um que recebeu dois WS com diâmetro maior ou igual a 1,5mm do diâmetro nominal do vaso.Todos os pacientes necessitaram de hiperinsuflação após o implante do WS. RESULTADOS - O sucesso do implante foi de 95 por cento. Os dois casos de insucesso foram: um devido à fratura do sistema e outro à soltura incompleta. Ambos, submetidos à angioplastia convencional com sucesso. Não houve complicaçöes nesta série. CONCLUSÄO - O WS foi efetivo no tratamento de LL e LM com alto índice de sucesso imediato e sem complicaçöes.

Coronary Less Shortening Wallstent in the Long Lesion of Coronary Artery Disease: 6 Months Follow-up Results

BACKGROUND: Despite of the first coronary wallstent implantation ushered in the new era in interventional cardiology with the purpose of circumventing the two major limitation of coronary balloon angioplasty, early acute occlusion and late restenosis, however, previous investigators suggested the high rate of subacute occlusion after original wallstent implantation. Recently the low incidence of the subacute closure and restenosis rate with the newely modified less shortening coronary wallstent in native coronary artery and in aortocoronary vein grafts were reported. In this study we report the acute and 6 months follow up results with less shortening coronary wall stent in 32 patients. METHODS: Thirty two patients were enrolled from March 1996 through February 1997 at the Yonsei cardiovascular center of Yonsei University. The specific angiographic criteria for enrollment included at least 70% stenosis and a lesion that was 20mm or more in length and a vessel diameter of at least 2.5mm. Enteric coated aspirin(100mg daily) and ticlopidine(500mg daily) at least 3 days before the procedure and received continuous infusion of 24,000U of heparin for 1day after the procedure. Angiography was performed in two orthogonal views at pre, post procedure and 6months later. Quantitative analysis was performed with the use of the electronic caliper comparing to the empty catheter. All continuous variables were expressed as mean SD and analyzed with the t-test. Differences between groups were analyzed with Chi-square analysis and Fishers Exact test where appropriate. RESULTS: The newly modified Coronary Less Shortening Wallstents were successfully implanted in all the 35 diffuse coronary lesions(more than 20mm in length) of the 32 patients, including 15 pts of acute myocardial infarction, 14 pts of unstable angina, and 3 pts of stable angina. Average 6 months follow up angiography was performed in 26 patients. Immediate angiographic results with Less Shortening Wallstent comparing with 6 months follow up were 3.0+/-0.4mm and 1.7+/-0.9mm in minimal luminal diameter(MLD), 5.1+/-9.1% and 46.8+/-25.8% in diameter stenosis(DS). During the in-hospital phase, no major cardiac event occurred except 2 cases of transmural myocardial infarction, including one of stent thrombosis(3.1%) and one of side branch occlusion, despite of inclusion of 7 cases of threatened occlusion in the long lesion. The restenosis rate at follow up angiography was 30.7%(8/26 pts). The restenosis rate was higher in patients with stent insertion into right coronary artery or adjuvant high pressure oversize ballooning after stent insertion but not statistically significant. CONCLUSIONS: The results of this study suggested that new Less Shortening Wallstent might reduce the requirement of multiple stent in the long lesion and a lower rate of subacute thrombotic occlusion in comparison to the reports with its prototype. Restenosis rate was not significantly different from other types of stents. Althouth the restenosis rate was high in patients with stent insertion, there was no statistical significance probably due to small sample size. But further large scale long term follow-up study is needed to evaluate the role of new Less Shortening Wallstent.

Coronary Less Shortening Wallstent in the Long Lesion of Coronary Disease : Immediate Results

BACKGROUND: Although the first coronary Wallstent implantation ushered in a new era in interventional cordiology with the purpose of circumventing the two major limitations of coronary balloon angioplasty, early acute occlusion and late restenosis, the previous investigators have reported a high rate of subacute occlusion after Wallstent implantation. However, recent studies have reported a low incidence rate of subacute closure and restenosis using the newly modified coronary Less Shortening in aortocoronary vein grafts. The present study reports the immediate results of the Less Shortening Wallstent Implantation for 21 diffuse native coronary lesions in 20 patients. METHODS: Twenty patients were enrolled at the Yonsei Univ. Cardiovasular Center of medical College, Yonsei University in Seoul, Korea from March 1996 through May 1996. The specific angiographic criteria for enrollment included at least 75% diameter stenosis, according to the estimate of two investigatior ; a lesion that was 20mm or more in lenght and a vessel diameter of at least 2.5mm. Bail-out procedure was performed in the case of abrupt closure or threatened closure, defined as a dissection and over 50% residual stenosis of the artery. RESULTS: The coronary Less Shortening Wallstents were successfully implanted in the 21 diffuse coronary lesions(more than 20mm in length) of the 20 patients(pts), including 7 pts of acute myocardial infarction, 11 pts of unstable angina, and 2 pts of stable angina. Angiographic results after Less Shortening Wallstent were 3.0+/-0.3mm in minimal luminal diameter(MLD), 6.7+/-10.8% diameter stenosis(DS) comparing with pre-stent implantation MLD and DS, respectively, 0.3+/-0.4mm and 89.9+/-8.4%. During the in-hospital phase, no major cardiac event occurred except 2 cases of transmural myocardial infarction, including one of stent thrombosis and one of side branch occlusion, despite of inclusion of 7 cases of threatened occlusion in the long lesion. The peristent spasms were observed in 11 among 21 lesions, although long term significance of peristent spasm is not defined. The relative risk for peristent spasm were 10 times higher when larger stents(expanded stent diameter/reference artery diameter>1.7) were implanted. There was no peristent spasm when stents of which expanded stent diameter 1.4 times smaller than reference artery size ware used. CONCLUSION: The results of this introductory study suggest that new Less Shortening Wallstent may reduce the requirement of multiple stent in the long lesion and a lower rate of thrombotic occusion in comparison to its prototype. Further large scale long term follow-up study is needed to evaluate the role of new Less Shortening Wallstent.

Treatment of Urethral Obstruction after Wallstent Implantation in Traumatic Urethral Stricture / 대한비뇨기과학회지

Endoscopic intraluminal implantation of a self expandable stent has been increasing in patients with recurrent urethral strictures because of its simple and relative safe technique. There has been a few reports concerning luminal obstruction after implantation of Wallstent. We have experienced 4 cases of urethral obstruction after variable period of Wallstent implantation in the treatment of traumatic urethral stricture. Herein the methods for treatment of urethral obstruction are discussed. The patients were managed with two different types of treatment. The first one was transurethral resection of granulation tissue inside Wallstent. The other is reinsertion of Wallstent inside the first one after transluminal resection of granulation tissue in patients with urethral obstruction occurring within 5 months after Wallstent implantation. Retrograde urethrography and urethroscopy after 3 months have demonstrated patency of urethra and epithelial covering of the implant. Our experience shows that in all 4 patients with traumatic urethral stricture have developed variable degrees of urethral obstruction after a variable period of wallstent implantation. Therefore, we consider that our method is one of the alternatives to treat urethral obstruction after wallstent implantation in patients with traumatic urethral stricture.

Self - expanding Wallstent for Palliative Treatment of Malignant Esophageal Stenosis / 대한소화기내시경학회지

The main objective of palliative treatment of malignant esophageal stenosis is rapid restoration of passage of fluid and solids. Endoscopic intubation with plastic endoprosthesis may lead to prompt relief of dysphagia and is a effective procedure for the palliative treatment of malignant esophageal stenosis. However, the insertion procedure, which necessitates prior dilatation, is traumatic and associated with considerable risk for perforation and bleeding. Tumor overgrowth, stent migration and stent blockage are frequent complications. Recently, self expanding metal stents woven in the form of tubular mesh made from surgical grade stainless steel alloy filaments(Wallstent), have been developed to offer possible advatage over conventional plastic tubes. The small diameter of introducer system carrying the compressed stent(18Fr) allows a relatively easy insertion procedure that dose not require prior dilatation. This stent is pliable. self-expanding and flexible in the longitudinal axis. We experienced a case of a 74-year-old male with malignant esophageal stenosis in whom self-expanding Wallstent was implanted with successful oral nutrition and much improvement of dysphagia.

Endoscopic Application of Self - Expanding Wallstent / 대한소화기내시경학회지

Nonsurgical endoscopic or percutaneous dilatation and insertion of an endoprosthesis is the treatment of choice in the majority of patiens with incurabie malignant biliary obsturction. But these palliative treatment of extrahepatic cholestasis with an endoscopic or percutaneous biliary endoprosthesis is limited by clogging. One of the factors thought to be of importance is the diameter of the stent. So in order to avoid being limited by the size of the instrumentation channel of the endoscope, expandable stents have been developed. Wallstent is braided in the form of a tubular mesh from surgical grade stainless alloy. This prosthesis is geometrically stable, pliable and self expanding. Its elastic properties are such that its diameter can be substantially reduced by moderate elongation. The stent is constrainded on a small diameter delivery catheter(total outside diameter: 9 French). During the implantation procedure the final position of the partially released endoprosthesis can be adjusted by gradual removal of the delivery catheter. If full expansion to 30 French occurs, the stent will be shortened by approximately 30% to their normal length range between 34-102mm. Now in this article we report a new method for endoscopic retrograde placement of biliary Wallstent in a patient with obsturctive jaundice due to periampullary choangiocacrcinoma.