Wallstent Endoprosthesis Research Articles

Technical Considerations in Covering and Deploying a Wallstent Endoprosthesis for the Salvage of a Failing Transjugular Intrahepatic Portosystemic Shunt

Technical Considerations in Covering and Deploying a Wallstent Endoprosthesis for the Salvage of a Failing Transjugular Intrahepatic Portosystemic Shunt

Self-Expanding Wallstent Endoprosthesis for Malignant Ureteral Obstruction

We present our experience with the self-expanding Wallstent endoprosthesis for ureteral recanalization in obstructive uropathy secondary to malignant pelvic disease. In total, 19 stents were inserted in 14 ureters. The follow-up included 100% of the patients. To date, except for one case, the patency of the stent has always persisted for the period of the survival of the patients, the longest ones being 4 and 4.1 years.

Malignant esophageal fistulas and perforations: management with plastic-covered metallic endoprostheses.

To evaluate prospectively the efficacy of plastic-covered metallic endoprostheses in patients with malignant esophageal fistulas and perforations. Thirty-nine patients with incurable esophageal carcinoma who developed esophagorespiratory fistulas (n = 20) or perforations (n = 19) were treated with plastic-covered metallic stents. Covered Wallstent endoprostheses were placed in 36 patients and covered Gianturco stents in three. All 19 perforations and 18 of 20 fistulas were successfully closed (clinical success rate, 95%). Symptoms of aspiration or dysphagia improved in all successfully treated patients. Mean survival was 81.8 days (range, 1-370 days). One patient with a closed perforation developed a fistula 16 weeks later and was treated with a second, overlapping stent; three patients with recurrent fistulas were treated with additional esophageal stents (one patient) or tracheal stents (two patients). In four patients, stent migration (two Gianturco and two Wallstent endoprostheses) necessitated placement of an additional stent. Covered metallic stents offer effective treatment for perforations and fistulas in patients with esophageal malignancy. Patients with recurrent fistulas can be treated with additional stents. Fistulas close to the upper esophageal sphincter may be closed with placement of parallel covered metallic stents in the esophagus and trachea.

Stent implantation in patients with superior vena cava syndrome.

The purpose of this study was to determine the feasibility of using Wallstent implantation to treat superior vena cava syndrome due to malignant tumors. Digital subtraction angiography showed obstruction of the superior vena cava in 13 patients who then underwent transluminal dilatation and Wallstent implantation. The patients were treated with IV heparin and monitored in the emergency department. Thereafter, they were treated with a platelet inhibitor for 4 weeks. Because their signs and symptoms improved, patients were able to resume radiation therapy, chemotherapy, or both. One patient died of cardiac arrhythmia 1 day after stent placement. Although eight patients have subsequently died of their bronchial or thyroid gland tumors, superior vena cava syndrome did not recur in any patient. Percutaneous implantation of Wallstent endoprostheses provides excellent palliation for superior vena cava syndrome.

Biliary wallstent endoprosthesis in malignant hilar obstruction: Long-term results with regard to the type of obstruction

Aim: To evaluate the clinical efficacy of percutaneously placed biliary Wallstents in the management of malignant hilar obstruction with regard to the obstruction type. Patients and methods: Sixty-six Wallstents were inserted in 41 patients with inoperable hilar obstruction: 13 patients had a type I obstruction according to Bismuth-classification, 18 a type II, eight a type III, and two a type IV obstruction, respectively. Clinical follow-up data were obtained from all the patients and the referring physicians. Results: Stent placement was technically successfully in all patients. The procedure-related death rate was 2% (one patient), but the overall 30-day mortality rate was 39%, mostly due to advanced malignant disease, cardiac failure or pneumonia. Stent occlusion was found in 11 patients (27%) after 87 days (mean; range, 8–190 days). After stent placement, the mean stent patency was 96 days and the mean survival was 131 days with no significant difference between patients with obstruction type I, II and III. Multivariate analysis revealed that patients with obstruction due to gallbladder carcinoma had a significantly shorter survival than patients with cholangio-carcinoma or hilar obstruction due to metastases. Conclusion: Overall, the insertion of Wallstent endoprostheses offers moderate results for palliation of hilar biliary obstruction regardless of the type of obstruction. In patients with cholangiocarcinoma, long-term results are good even for complicated strictures (type III). In patients with hilar obstruction due to gallbladder carcinoma the outcome is generally poor, regardless of the type of obstruction.

Treatment of Benign Venous Strictures with the Wallstent Endoprosthesis

Objective: Treatment of benign venous strictures with the Wallstent endoprosthesis. Design: A retrospective study of a patient group with benign venous strictures. Setting: Departments of Radiology and Surgery in a London teaching hospital. Patients: Three patients with clinically significant benign venous strictures. Interventions: Successful placement of the Wallstent endoprosthesis following failed angioplasty. Main outcome measures: Maintained clinical stent patency at follow-up. Results: All patients reported a good symptomatic improvement and this was confirmed by reduction in swelling of the affected limb on clinical examination Doppler examination in one case confirmed stent patency at 1 year. Conclusion: The role of the Wallstent endoprosthesis in the treatment of benign venous strictures deserves evaluation by prospective study. The successful outcome in the three patients reported indicates its clinical application.

Metallic endoprostheses for malignant tracheobronchial obstruction: initial experience.

To assess the efficacy of the Wallstent endoprosthesis in malignant tracheobronchial obstruction. Seven patients with irresectable carcinoma of the bronchus were treated with nine Wallstent endoprostheses. The procedures were performed under endoscopic and fluoroscopic guidance. Wallstent endoprostheses ranging from 8-16 mm in diameter and 26-49 mm in length were deployed after balloon dilatation of the strictures. All stents were successfully deployed in the desired positions. There was one procedural complication and one procedure related death. Three patients showed significant improvement in respiratory status after stenting. At a mean follow-up of 5.1 months, there has been no stent migration, fracture, or collapse. One patient had proximal tumor overgrowth that was treated with additional stent insertion. One patient died after a bout of massive hemoptysis 3 months poststenting and it was difficult to tell whether this was related to the endoprosthesis. The use of the Wallstent endoprosthesis in malignant tracheobronchial obstruction is technically feasible.

Covered self-expanding transhepatic biliary stents: clinical pilot study.

We report our preliminary results with a new type of self-expanding covered stent for treatment of malignant biliary obstruction. Wallstents, fully covered with high elasticity polyurethane, with an unconstrained diameter of 10 mm and a total length of 69 mm, were placed transhepatically under fluoroscopic guidance in five patients. The length of the biliary obstruction varied between 30-50 mm. At 1 and 3 months (82-98 days) clinical assessment, serum bilirubin measurement, and ultrasound examination of the biliary tree were performed. Initial uncomplicated deployment of the stents and internal drainage was possible in all patients. Distal stent migration resulted in early biliary reobstruction in one patient. At 3-month follow-up, partial reobstruction, most probably due to sludge formation, was found in another patient. Our initial results indicate that the covered, self-expanding Wallstent endoprosthesis can be reliably and safely deployed transhepatically for malignant biliary obstruction.

Treatment of malignant obstruction of the superior vena cava with the self-expanding Wallstent.

Obstruction of the superior vena cava (SVC) in malignant disease can cause considerable distress to patients. Symptomatic relief can be achieved by the percutaneous implantation of a self-expanding stent (Wallstent) into the stenosis. Fourteen patients with obstruction of the SVC were treated with one to three Wallstent endoprostheses. They suffered from advanced bronchogenic carcinoma (n = 12), thyroid carcinoma (n = 1), and breast carcinoma (n = 1). The indication for stent placement was symptomatic obstruction of the SVC and incurable disease. Stenting was performed for symptom relief, and before, during, and after courses of radiotherapy or chemotherapy as needed. Twelve patients experienced complete symptomatic relief within two days of stent placement. Two patients did not benefit. Three patients not given anticoagulation developed stent thrombosis between one week and eight months after initial placement, and within one day of endobronchial stent implantation with bronchial laser therapy or balloon dilatation in all three. Patency of the SVC was achieved again by a repeat procedure. Stent placement for obstruction of the SVC gives rapid symptomatic relief. Subsequent endobronchial stent implantation with bronchial laser therapy or balloon dilatation could be a risk for caval stent occlusion. Stent thrombosis remains a problem in patients who are not anticoagulated.

Superior vena cava stent placement: results with the Wallstent endoprosthesis.

To assess the clinical success and short-term patency of the Wallstent endoprosthesis in the treatment of superior vena cava (SVC) syndrome. Twenty-one 14-mm-diameter endoprostheses were implanted in 15 patients (mean age, 60 years) treated for SVC syndrome due to malignant compression (n = 14) or postirradiation fibrotic stenosis (n = 1) of the SVC. Immediate technical success was achieved in all patients. Two early complications occurred: retroperitoneal hemorrhage due to venous iliac tear and early stent thrombosis. In the 14 patients without early stent occlusion, stent placement resulted in complete relief of SVC syndrome; clinical success was 93%. SVC syndrome did not recur from 1 to 14 months, until the patient died (n = 11) or until the end of the study (n = 3). Helical CT showed a patent stent in five patients, respectively, at 3, 6, 8, 10, and 11 months. SVC stent placement has good clinical results and a high patency rate at short-term follow-up in patients with SVC syndrome.

Release of entrapped delivery devices from wire mesh stents

Obstruction is the major problem with biliary and pancreatic stents. This can occur from sludge, blood clots, tumor ingrowth, or overgrowth.1-4 Expanding metal stents have decreased this problem. These stents have been carefully evaluated in controlled studies and have been shown to function longer than plastic stents.5-8 Wire mesh stents have generally been easier to implant than the plastic stents. However, Jowell et al.9 reported five patients, and Abdulian and Chen10 reported one patient, in whom the delivery device was impacted in the tip of the partially opened Wallstent endoprosthesis (Schneider Inc., Plymouth, Minn.).

Treatment of Ureteral Obstructions with the Wallstent Endoprosthesis: Preliminary Results

To evaluate the efficacy of the Wallstent endoprosthesis in the treatment of ureteral strictures. Wallstents with diameters of 10 mm were placed across five malignant and six benign ureteral strictures in eight patients. All patients were believed to have poor surgical options, and their strictures were being maintained with catheter drainage. Ten lesions involved ureteroenteric anastomoses, and one malignancy involved the midureter. Three stents (two patients) across malignant disease remained patent until the time of patient death (3-5 months); the remaining two stents (one patient) became occluded within 1 month. Only one of six stents placed for benign disease remained patent at 11 months. All occlusions in benign strictures resulted from ingrowth of hyperplastic urothelium and granulation tissue. Complete obstruction was usually present only focally within the stent. The malignant occlusions were caused by tumor ingrowth and granulation tissue. No major complications were directly related to the stents, but two infections occurred. Wallstent endoprostheses are ineffective in providing long-term relief in patients with benign ureteroenteric strictures. Further evaluation of their role in malignant strictures is needed.

Plastic-covered metallic endoprostheses in the management of oesophageal perforation in patients with oesophageal carcinoma

To evaluate the role of plastic-covered self-expanding metallic endoprostheses in patients with oesophageal perforation occurring during endoscopically guided dilatation prior to laser treatment for malignant obstruction. Six patients with oesophageal perforation following laser treatment for malignant obstruction were treated. Four patients received the polyurethane-covered Wallstent endoprosthesis (Schneider SA, Bulach, Switzerland) and two patients the barbed polyethylene-covered Gianturco stent (William Cook, Europe). All patients had successful stent placement under intravenous sedation and fluoroscopic guidance with immediate relief of dysphagia and sealing of the perforation. Following the procedure all patients could eat either a normal diet or soft food and five patients were discharged within 3-4 days. None of the serious sequelae usually associated with oesophageal perforation were observed. Two patients required second overlapping stents to be inserted within 1 week because of minor migration of the initial endoprostheses. In one patient two stents were necessary because the carcinoma extended over 17 cm. Five patients died after stent insertion (mean survival time = 49 days, range 16-80; median survival time = 37 days, range 16-80) due to a general deterioration in their condition, although all could swallow normally until death. The remaining patient was well and tolerating a light diet at 1 month. This technique is quick, safe and cost-effective and is now our preferred method of managing malignant oesophageal obstruction associated with perforation.

The use of the wallstent endovascular prosthesis in the treatment of malignant inferior vena cava obstruction

We report three cases of inferior vena cava (IVC) obstruction due to metastatic liver disease treated with a self-expanding Wallstent endoprosthesis (Schneider SA, Zurich, Switzerland). All three patients experienced symptomatic relief during their remaining few weeks of life. The Wallstent is effective and easy to deploy, and should be considered for use in the management of such patients. The literature to date on IVC stenting is also reviewed.

Malignant biliary obstruction treated by Wallstents and Strecker tantalum stents: a retrospective review.

To evaluate retrospectively the role and the effectiveness of self-expandable Wallstents and balloon-expandable Strecker stents in patients with inoperable malignant obstruction of the biliary tree. Fifty patients with malignant biliary obstruction were treated from August 1991 to August 1992 by percutaneous placement of 55 metallic endoprostheses (39 Wallstents, 16 Strecker stents). All patients were followed by clinical evaluation, laboratory data, and ultrasonographic examination until death. Wallstent placement was successful in 36 patients without procedure-related complications. One partial occlusion after 1 year was resolved by percutaneous balloon dilatation. Fourteen patients were treated with 16 Strecker stents. Stenting was unsuccessful in four cases; four occlusions (after 6 h, 48 h, 2 and 6 months) were encountered. Wallstent endoprostheses have good results and long-term patency. There were some problems with Strecker stents during the placement and there was a higher occlusion rate.

Magnetic resonance angiography of intravascular endoprostheses: investigation of three devices.

To assess the value of magnetic resonance angiography (MRA) in the evaluation of vascular patency after intravascular endoprosthesis placement. Three different metallic stents (Wallstent, Strecker, Palmaz) were studied in vitro, and in vivo in six patients with spin-echo (SE) and gradient-echo (GRE) MR imaging. Time-of-flight, two-dimensional (2D) gadolinium-enhanced MRA was performed with GRE and flow-compensation technique, and reconstructed with a maximum-intensity projection (MIP) algorithm. MRA was compared to digital angiograms. In vitro studies demonstrated that the signal intensity (SI) within the stent differed according to the device employed, the lowest SI being observed within the Palmaz stent (p = .001). There was no difference in SI or apparent diameter of the stent according to the sequence (SE vs GRE) or length of echo time (TE). In patients, the endoprostheses recorded as a well-defined area of signal void or drop-out (p = 0.004), whereas vessels above and below the stent displayed high signal intensities. MRA does not seem as yet to be well suited for evaluating vascular patency after endoprosthesis placement, even if the Strecker and Wallstent endoprostheses provide fewer artifacts than the Palmaz stent.

Renal Artery Stent Placement: Immediate and Midterm Technical and Clinical Results

The authors report their experience with implantation of self-expandable stents into renal arteries. Twenty-five Wallstent endoprostheses were deployed into 18 renal arteries in 18 patients. Atheroma was the cause of the initial renal artery lesion in 15 patients (four ostial, 10 postostial, and one long occlusion). In these 15 patients, indications for stent placement were 12 immediate failures of percutaneous transluminal renal angioplasty (PTRA), two immediate PTRA complications (dissections), and one recurrent stenosis. The other renal artery lesions were three dissections (two spontaneous and one after catheterization). The procedure was technically successful in all patients, with residual stenosis less than 20%. However, five stents were slightly misplaced and a second stent was implanted to fully cover the lesion. Three complications occurred: one acute thrombosis 15 days after stent implantation that was successfully treated with local fibrinolysis, one asymptomatic occlusion due to early thrombosis or to delayed restenosis, and one segmental renal infarction related to extensive dissection after PTRA and not to stent placement. Following stent implantation, systolic blood pressure (P = .006) and diastolic blood pressure (P = .002) measured at 6 months decreased significantly. Angiographic follow-up was obtained in 16 patients (with intravenous technique in nine and intraarterial digital subtraction angiography in seven) at a mean of 11 months after stent placement, and ultrasonographic follow-up was obtained in the two others after 8 and 25 months, respectively. A normal patent renal artery was demonstrated in 16 patients (89%); there was one restenosis with a 75% reduction in diameter of the renal artery and the asymptomatic occlusion above mentioned. Self-expandable stent implantation is a promising technique in PTRA failures. Wallstent placement is technically feasible. Immediate results were satisfactory and the midterm restenosis rate was low in this series of patients.

Oesophageal perforation treatment with plastic-covered wallstent endoprostheses

Oesophageal perforation treatment with plastic-covered wallstent endoprostheses

Renal artery stent placement: long-term results with the Wallstent endoprosthesis.

To evaluate clinical success and long-term patency of a Wallstent in the renal artery. Twenty-five Wallstents were placed in 21 patients to treat delayed restenosis after previous balloon angioplasty (n = 13) or inadequate immediate postangioplasty response (n = 8). Indications for angioplasty were hypertension in all patients and renal preservation in seven. Stenosis was atheromatous in 15 patients, involving ostium in seven. Stent placement was successful in all patients. At follow-up angiography (range, 12-60 months), four patients (20%) had stent restenosis. Of these, three had undergone treatment for restenosis after angioplasty and three had ostial lesions. Cumulative primary patency rate was 95%, 85%, and 77% at 7, 9, and 15 months, respectively. Hypertension was cured in three patients and improved in 18. Arterial stent placement has good clinical results and high long-term patency rates after conventional renal angiography or delayed restenosis, especially in ostial lesions.

Life-threatening pulmonary emboli and cor pulmonale: treatment with percutaneous pulmonary artery stent placement.

Large, central bilateral pulmonary emboli led to cor pulmonale and severe hypoxemia in a patient who had recently undergone cardiac surgery. After percutaneous catheter fragmentation and thrombolysis of the emboli failed, the left and right interlobal pulmonary arteries were recanalized by placement of self-expanding Wallstent endoprostheses through the clots. Pulmonary perfusion was restored to the lower lobes, and the patient demonstrated rapid clinical improvement.