Wallstent Placement Research Articles

Endoscopic management of occluded biliary Wallstents: a cancer center experience

Background Biliary obstruction caused by unresectable malignancy commonly is treated by placement of a biliary self-expandable metallic stent. The endoscopic and percutaneous techniques for self-expandable metallic stent placement are well established and can be performed with a high success rate. Self-expandable metallic stent placement affords palliation of pruritus and enables treatment of advanced cancer with chemotherapeutic agents metabolized by the liver. Unfortunately, these stents tend to occlude with time. Optimal management of an occluded self-expandable metallic stent remains to be determined. Methods A retrospective review was undertaken to determine optimal management of the occluded self-expandable metallic stent. Patients with malignant biliary obstruction who had endoscopic management for occluded Wallstents that had been placed percutaneously and endoscopically were studied. All patients underwent ERCP with one of the following interventions: mechanical cleaning, insertion of a plastic stent within the Wallstent, or insertion of a second Wallstent. The effectiveness of the intervention and duration of stent patency thereafter was studied. Results A total of 34 patients with occluded biliary Wallstents underwent the following procedures: mechanical cleaning (6 patients), placement of a second Wallstent (4), or insertion of a plastic stent (24). Mechanical cleaning was effective in only one of 6 patients. For all 4 patients who underwent placement of a second Wallstent, there was resolution of jaundice or cholangitis and no reocclusion. Plastic stent insertion was successful in 22 of 24 patients. Median duration of stent patency after intervention was 192 days (range 81-257 days) after second Wallstent placement, 90 days (11-393 days) after plastic stent insertion, and 21 days (3-263 days) after mechanical cleaning. Duration of stent patency was better when the initial malignant stricture involved the distal vs. the proximal bile duct. Conclusions Occlusion of a biliary Wallstent is best managed by endoscopic insertion of a second Wallstent or a plastic stent. Mechanical cleaning is less effective. The level of the initial biliary obstruction influences stent patency.

Complication of benign tracheobronchial strictures by self-expanding metal stents

ObjectivesSelf-expanding metal stents are used to palliate benign strictures. We examined the complications of this approach. MethodsBetween 1997 and 2002, we observed recurrent airway obstruction and extension of benign inflammatory strictures after the placement of tracheobronchial Microvasive Ultraflex stents and Wallstents (Boston Scientific Corp, Natick, Mass), in 10 patients with postintubation strictures and 5 with other indications; all but 1 patient were referred to us. Patients with tracheal (9), subglottic (1), combined tracheal and subglottic (3), and bronchial (2) strictures had been treated with covered and uncovered Wallstents (6) and Microvasive Ultraflex stents (9). ResultsAfter stent insertion, stricture and granulations within previously normal airway were seen in all patients. New subglottic strictures resulting from the stent caused hoarseness in 4 patients. A bronchoesophageal fistula was found in 1 patient at presentation and a tracheoesophageal fistula in another during extraction of a Wallstent. Primary surgical reconstruction, judged to have been feasible before wire stent insertion in 10 patients, was possible after stenting in only 7 and failed in 2. Palliative tubes were placed in 60% (9/15). Self-expanding metal stents may lengthen luminal damage, incite subglottic strictures, and cause esophagorespiratory fistula in inflammatory airway strictures. The injury is severe, occurs after a short duration of stenting, and precludes definitive surgical treatment or requires more extensive tracheal resection. ConclusionThe current generation of self-expanding metal stents should be avoided in benign strictures of trachea and bronchi.

Endovascular treatment of malignant superior vena cava syndrome: is bilateral wallstent placement superior to unilateral placement?

To report our experience with unilateral versus bilateral stent placement in the treatment of malignant superior vena cava syndrome (SVCS). The records and films of 84 consecutive patients (69 men; mean age 64+/-10 years, range 39-79) referred for stent placement in malignant SVCS were reviewed for venous compromise, technical and clinical success, complications, and reocclusions. Wallstents were placed covering the SVC and both (bilateral technique) brachiocephalic veins (BCV) preferentially; unilateral stenting of only one BCV in addition to the SVC was performed based on operator preference or inability to access both sides. Technical success was defined as the ability to stent the SVC and at least one BCV; clinical success was the elimination of SVCS symptoms. Technical success was achieved in 83 (99%) patients, using the unilateral technique in 22 and bilateral stenting in 61 patients. The groups did not differ with regard to age, sex, underlying diseases, or location and extent of venous compromise. Immediate clinical success was achieved in 20 (91%) of 22 patients in the unilateral group and 55 (90%) of 61 patients in the bilateral group. Two patients suffered late occlusion in the unilateral group, while in the bilateral group, 8 patients had early occlusion and 9 had late occlusion. Thus, the total occlusion rate was significantly (p<0.05) lower in the unilateral group. There was 1 other complication (pericardial tamponade) in the bilateral group, for a 28% total complication rate, which was significantly higher (p=0.039) than the 9% in the unilateral group. The 1, 3, 6, and 12-month primary stent patency rates were 90%, 81%, 76%, and 69%, respectively. Patency tended to last longer in the unilateral group, but the difference was not significant (p=0.11). Although bilateral Wallstent placement achieved equal technical and clinical success, it tended to confer shorter-lived patency and caused more complications.

Endovascular Treatment of Malignant Superior Vena Cava Syndrome:Is Bilateral Wallstent Placement Superior to Unilateral Placement?

<b>Endovascular Treatment of Malignant Superior Vena Cava Syndrome:</b>Is Bilateral Wallstent Placement Superior to Unilateral Placement?

Wall stent-enhanced lateral pancreaticojejunostomy for small-duct pancreatitis.

The purpose of this study was to see if a small (<7 mm) pancreatic duct could be dilated to an acceptable diameter, allowing lateral pancreaticojejunostomy to decompress the pancreatic duct and relieve pain, while preserving pancreatic endocrine and exocrine function. Patients with chronic pancreatitis who had a small main pancreatic duct underwent progressive trans-ampullary dilation of the duct and subsequent placement of an expandable metallic wall stent (wallstent; Boston Scientific Microvasive Division, Natick, Mass). Approximately 14 days later, a lateral pancreaticojejunostomy was done. A 400-bed university referral center hospital in an urban setting. Thirty-five patients were selected from a large group with chronic pancreatitis. Thirty-one had pancreas divisum. All patients had undergone transendoscopic sphincterotomies and stenting before being accepted into the study. All had endoscopic retrograde cholangiopancreatography-proven chronic pancreatitis, and all ducts were observed to be 7 mm or smaller. Patients were selected after endoscopic sphincterotomy and stenting failed. Progressive transendoscopic duct dilation with plastic stents was carried out, and a 10-mm expandable metallic wall stent was placed prior to surgical decompression. Lateral pancreaticojejunostomy was performed. Patients were observed for pain relief, postoperative symptoms, analgesic use, glucose intolerance, and quality of life. All patients were seen or contacted by telephone, and their results were recorded. There were no operative deaths, but 26% of patients had complications. Seventy-one percent of patients reported that their pain was better than preoperatively. Three patients had subsequent pancreatic surgery. No new cases of diabetes occurred except in the 2 patients who underwent total pancreatectomy. In general, most patients feel that their lives were improved by the procedure. A quarter of the patients no longer take narcotics, and many have been able to resume a relatively normal lifestyle. Although this procedure is not a panacea for all patients with chronic pancreatitis and a nondilated duct, it is a reasonable alternative to resection.

Ureteropelvic Junction Obstruction: An Innovative Approach Combining Metallic Stenting and Virtual Endoscopy

We report our experience with auto-expandable metallic stents for treating ureteropelvic junction obstruction. We treated 4 patients with a mean age of 45 years who had ureteropelvic junction obstruction with placement of a self-expandable intraureteral metallic stent (Wallstent, Schneider, Zurich, Switzerland). All patients presented with recurrent ureteropelvic junction obstruction after open pyeloplasty. Excretory urography and 3-dimensional reconstruction computerized tomography were performed 1 and 6 months after stent insertion. Virtual endoscopy images were obtained at followup due to the need to define ureteral patency. Mean followup was 16 months (range 9 to 24). Wallstent placement was successful and immediate patency was achieved in all cases. During followup 3 patients required no further intervention and the stented ureteropelvic junction remained patent. In the remaining patient stricture recurred 2 months after initial stent insertion due to the ingrowth of scar tissue through the prosthesis. Additional intervention was deemed necessary after placing a longer 6 cm., completely coaxial overlapping metal stent. Virtual endoscopy and excretory urography findings concurred. Virtual endoscopy allows visualization of the stented ureteropelvic junction lumen cephalad and caudal to the prosthesis. It also enables easy navigation within the stent at different angles of view. The concept of applying metallic stents for ureteropelvic junction obstruction and adjacent adynamic ureteral segments combined with virtual endoscopy is strengthened by the results of this study.

Single-center experience with carotid stent restenosis.

To report the angiographic morphology of carotid stent restenosis and the possible therapies based on data from a single-center experience. In a 45-month period, 279 patients (196 men; mean age 70 +/- 9 years, range 50-89) underwent successful Wallstent placement in 303 stenotic internal carotid arteries (ICA). Patients were followed with duplex sonography; angiography was used to confirm any significant (> or =70%) recurrent lesions detected on the ultrasound scan. Further balloon dilation with or without stent placement was undertaken. RESULTS; Over a median 12-month follow-up (interquartile range 6-24), there were 9 (3.0%) carotid stent restenoses found, all within 12 months after stent placement. Two types of restenosis were differentiated. In the more common form, "in-stent" stenoses (n = 6) were detected and treated with stent placement; lasting success (patency >12 months after retreatment) was achieved in 4. Early second and third recurrences arose in the other 2 stents within 3 months of the first retreatment; additional stents were placed at each recurrence. Both patients suffered a major cerebral event after 17 months. Less often, an "end of stent" stenosis (n = 3) developed at a kink in the ICA adjacent to the cephalad end of the stent. Lasting success was achieved by balloon dilation without additional stent placement in all 3 cases. No procedure-related complications were observed within 30 days after any treatment for restenosis. Carotid stent restenosis, which occurs rarely after 1 year, can be treated safely by further percutaneous interventions.

Utility of MR Cholangiography for Follow-up Examination after Metallic Stent Placement in the Bile Duct

Purpose: To evaluate the efficacy of MR cholangiography for follow-up examination after metallic stent placement in the bile duct. Materials and Methods: Between December 1999 and June 2000, 15 patients with biliary obstruction in whom metallic biliary stents had been placed underwent MR cholangiography during follow-up examination. The causes of obstruction were hilar cholangiocarcinoma (n=6), common bile duct cancer (n=5), gall bladder cancer (n=1) and pancreatic cancer (n=3). The types of self-expandable metallic stent employed were the nitinol stent (n=2), the Endocoil nitinol stent (n=3), the Ultraflexed Diamond stent (n=5), and the Wallstent (n=5). Using MR cholangiography, we measured the diameter of that part of the biliary stent which showed high signal intensity, assigning one point if this was less than one third of the stent diameter, two points if between one third and two thirds, and three points if more than two thirds. We decided that a higher score indicated fewer artifacts. Results: The score was 1.7-3 (mean, 2.3) points for the Endocoil nitinol stent, 1.7-2.3 (mean, 2) for the nitinot stent, and 1-3 (mean, 1.7) for the Ultraflex Diamond stant. In most cases, two thirds of the stent diameter was observed. For the Wallstent, the score was 1-1.7 (mean, 1.3) points and the inner portion of the stent was almost invisible. Conclusion: MR cholangiography is not useful for follow-up examination after the placement of Wallstents and three other types of nitinol stent in the bile duct.

Long term follow up of Wallstent placement for benign biliary strictures

Long term follow up of Wallstent placement for benign biliary strictures

Rupture of an Abdominal Aortic Aneurysm due to Aortic Wallstent Dislocation Masquerading as Renal Colic

Placement of an aortic wallstent for treatment of an abdominal aortic aneurysm (AAA) is a frequent therapeutic measure. Whereas AAA is known to mimic renal colic, aortic wallstent dislocation is a novel diagnostic problem. Herein, we report the first case of a patient with a dislocated aortic wallstent and subsequent aneurysm rupture and discuss appropriate diagnostic measures.

Endovascular Treatment of Iliac Limb Stenoses or Occlusions in 31 Patients Treated with the Ancure Endograft

The authors report their experience with treatment of iliac limb complications in patients treated with the Ancure endograft with Wallstents to provide additional support and thrombolysis when needed. From February 1996 to October 1999, 88 patients were treated for abdominal aortic aneurysm with use of the Ancure endograft. Of the 88 devices used, 20 were tube grafts and the remaining 68 devices had a total of 130 iliac limbs (bifurcated, n = 62; aortoiliac, n = 6). After graft deployment, all patients underwent intraoperative aortography; since July 1997, intravascular ultrasound (IVUS) has also been used. Thirty-one patients (46%) required treatment of 47 (36%) limbs with Wallstents. Graft narrowing was observed in 41 limbs (27 patients) with IVUS immediately after graft deployment. All were successfully treated with placement of Wallstents. Before routine use of intraoperative IVUS, three patients presented between 2 and 6 weeks postoperatively with iliac limb thrombosis. All three limbs were successfully treated with thrombolysis and Wallstent placement to correct the underlying iliac problem. Additionally, two contralateral limbs in these three patients were also noted to have stenosis and were treated with use of Wallstents. The last patient required placement of a Wallstent to treat stenosis of surgical anastomosis of the iliac limb of an aortoiliac endograft at 3 days. All Wallstent-reinforced Ancure endografts remained patent from 1 to 36 months (mean, 14 months). After placement of an Ancure bifurcated or aortoiliac endograft, iliac limb stenosis is easily detected with use of intraoperative IVUS. Such complications can be safely corrected with Wallstent placement. Postoperative limb occlusion at the authors' institution has been eliminated with such intervention.

4751 Management of malignant duodenal strictures caused by pancreatic carcinoma with expandable stents.

Pancreatic carcinoma is the second leading gastrointestinal cancer in the United States. Curative surgical procedures are rare at the time of initial Dx (< than 15%). Palliative endoscopic treatment options therefore take on a major role in pts with unresectable lesions. These include biliary and pancreatic endoscopic prosthesis for obstructed ducts as well as EUS-guided celiac plexus neurolysis for refractory abdominal pain. A less well known complication but equally important is treatment of high-grade duodenal strictures resulting in gastric outlet obstruction. AIM: To determine the effectiveness and complication rate of expandable metal stents in the treatment of malignant duodenal strictures. METHODS: Eleven pts, 8-W, 3-M, (age range 72-86, mean 76) underwent placement of enteral wall stents (Boston Scientific). All patients had unresectable pancreatic carcinomas involving the head of the pancreas. These pts were previously treated with biliary endoprosthesis (11) and pancreatic endoprosthesis (2). Time between biliary endoprosthesis and presentation of duodenal obstruction was 5 months to 13 months (mean 8.7 months). RESULTS: All pts underwent successful placement of expandable metal stents (size 20 mm diameter, Length 90 mm=4, 60 mm=7). None of the strictures were initially traversable with standard upper endoscope and required placement of an 0.35" guidewire beyond the stricture under fluoroscopic control to assist in deployment/positioning of the wall stent. Mean follow-up was 12.5 months (range 7-18 months). There were 2 complications related to wall stents, both perforations at the level of the proximal stent margin (1) and distal stent margin (1) presenting at 5 weeks and 12 weeks after deployment respectively. The perforations were felt to be directly related to the bare barbs at each end of the wall stent design. Both pts underwent successful surgical palliation. Survival, post duodenal wall stents, was 6.8 months (Range 4-13 months). Two pts are alive with good palliation of their duodenal obstruction. CONCLUSION: Expandable metallic stents are effective and provide a reasonably good palliative option for unresectable pancreatic carcinoma with duodenal strictures. The relative high rate of complication would require further modification in stent design.

4641 A new covered biliary wallstent: effectiveness in the palliation of malignant obstruction jaundice, results from a multicentre trial.

Background: Uncovered metal biliary stents have superior patency rates compared to plastic stents in the palliation of malignant biliary strictures. The rate of tumor ingrowth may be decreased by the use of a covered metal stent. This report describes a multicentre experience with a new covered Wallstent(Microvasive, Natick, USA)in 33 patients with malignant bile duct obstruction. The new design incorporates a silicone coating. This study was sponsored by Microvasive Endoscopy, Boston Scientific Corporation. Patients and Methods: 33 patients, 17 male, mean age 68 yr,(32 - 92)were included in the study. 21 (64%)patients had pancreatic carcinoma, 5 (15%) gastric carcinoma (3 BII gastrectomy), 3 (9%) cholangiocarcinoma, 1 (3%) ampullary carcinoma, 1 (3%) hepatoma,1 (3%) metastatic breast carcinoma and 1 unconfirmed. 25 (76%) had prior stent placement(1 metal). The length of obstruction ranged from 10 to 54 mm (mean 27 mm). Covered stents were placed in 8 pts transhepatically (San Francisco, Miami), in the remaining 25 pts endoscopic placement under fluoroscopic control (Toronto, Calgary). Results: Stent deployment was satisfactory in 31 out of 33 cases. Stent positioning was not optimal in 2 pts (1 transhepatic, 1 endoscopic) requiring immediate placement of additional uncovered Wallstents. Radial expansion ranged from 25 to 100%. Mean bilirubin level decreased from 150 μmol/L to 24 μmol/L at 1 month. Early complications included minor pain in 2 pts and acute cholecystitis in 1 pt requiring cholecystectomy. At 6 months, 15 pts had died, none with stent related complications. Among the 16 living pts, 3 developed obstructive jaundice (3-6 mos), 2 due to partial migration and one due to sludge. Overall 6 month complication rate was 19% (6/31). Conclusions:The new covered Wallstent remained patent until death or at 6 mos follow up in 28/31 pts. There was no evidence of ingrowth or overgrowth and in 2 cases obstruction at the proximal end of the stent could be attributed to partial migration. The design of this covered stent offers the potential of prolonged patency.

Hepatocellular carcinoma extending into the portal vein: Restoration of extended-term patency by placement of uncovered wallstents

A 74-year-old man presented with hepatocellular carcinoma extending into the main portal vein. Two bare Wallstents were placed to maintain portal vein patency. The main portal vein remained patent for 6 months after treatment. No serious complications were observed during or after treatment.

Deep Venous Thrombosis in the Lower Extremity: Catheter-Directed Thrombolysis

To evaluate the efficacy of catheter-directed thrombolysis in treating symptomatic deep venous thrombosis (DVT) in lower limbs. Materials and Methods: Twenty-six consecutive patients (16 male and 10 female; mean age, 55 years) with lower extremity DVT underwent thrombolytic therapy. The duration of symptoms was 1 -90 (mean, 17) days: 20 days or less in 16 cases (acute DVT) and less than 20 days in ten (chronic DVT). Catheter-directed infusions of urokinase were administered via ipsilateral popliteal veins, and angioplasty or stent placement was per-formed after the thrombolytic procedure. Oral medication of warfarin continued for six months, and for the evaluation of venous patency, follow-up ultrasonography was performed. The total dose of infused urokinase was 1,750,000 -10,000,000 (mean 4, 84,000) IU, and the total procedural time was 25 -115 (mean, 64) hours. Results: Lysis was complete in 16 cases (62%, all acute DVT), partial in five (19%, chronic DVT), and failed in five (19%, chronic DVT). Eight patients with venous stenosis and two with occlusion were treated by means of angioplasty (n=4) or Wallstent placement (n=6). Minor bleeding occurred in six cases and major complications in two (one of pulmonary embolism, and one of multiorgan failure). Conclusion: Catheter-directed thrombolysis with urokinase is effective for the treatment of DVT in lower limbs.

Treatment of hemodialysis-related central venous stenosis or occlusion: results of primary Wallstent placement and follow-up in 50 patients.

To analyze the effectiveness of stent placement as the primary treatment for central venous obstruction in patients undergoing hemodialysis. Fifty-seven Wallstents were placed in 50 patients with symptomatic shunt dysfunction and arm swelling due to central venous obstruction. Technical success, complication, and patency rates were evaluated. Stent deployment was successful in all patients, and early rethrombosis (within 1 week) was noted in one patient (2%). Seventy-three episodes of reobstruction occurred and were treated percutaneously with angioplasty alone in 54 cases (74%). Nineteen cases (26%) necessitated additional stent placement. The 3-, 6-, 12-, and 24-month primary patency rates were 92%, 84%, 56%, and 28%, respectively. Cumulative overall stent patency was 97% after 6 and 12 months, 89% after 24 months, and 81% after 36 and 48 months. In the treatment of brachiocephalic and subclavian venous obstruction, stent placement shows excellent technical results and helps preserve vascular access for a substantial period. Multiple repeat interventions are, however, frequently required to maintain patency.

Patency of Wallstents placed across the venous anastomosis of hemodialysis grafts after percutaneous recanalization.

To determine the patency of Wallstents placed across the venous anastomosis of prosthetic bridge grafts after percutaneous graft recanalization. Wallstents were placed across 26 lesions at the venous anastomosis of polytetrafluoroethylene (PTFE) grafts in 25 patients (11 men, 14 women; age range, 29-83 years; mean age, 65.4 years) after pulse-spray pharmacomechanical thrombolysis. Indications for stent deployment included acute angioplasty failure, rapid restenosis, and vessel perforation. The initial success rate was 100%. The mean primary graft patency rates (+/- standard error) at 3 and 6 months were 34% +/- 9 and 27% +/- 9, respectively. Secondary patency rates were 77% +/- 8 at 3 months, 72% +/- 9 at 6 months, and 50% +/- 10 at 12 months. Eight of the 26 grafts continued to be used for hemodialysis at the end of follow-up. After angioplasty failure or vessel perforation, Wallstent placement at the venous anastomosis of recanalized PTFE grafts can salvage hemodialysis access function. The results of this study indicate that the 1-year secondary patency rate of these grafts is 50%, which approaches the reported rates of patency after balloon dilation as part of percutaneous graft recanalization.

Reconstruction of the superior vena cava: Benefits of postoperative surveillance and secondary endovascular interventions

Purpose: Superior vena cava (SVC) reconstructions are rarely performed; therefore the need for surveillance and the results of secondary interventions are unknown. Methods: During a 14-year period 19 patients (11 male, 8 female; mean age 41.9 years, range 8 to 69 years) underwent SVC reconstruction for symptomatic nonmalignant disease. Causes included mediastinal fibrosis (n = 12), indwelling foreign bodies (n = 4), idiopathic thrombosis (n = 2), and antithrombin III deficiency (n = 1). Spiral saphenous vein graft (n = 14), polytetrafluoroethylene (n = 4), or human allograft (n = 1) was implanted. Results: No early death or pulmonary embolism occurred. Four early graft stenoses or thromboses (spiral saphenous vein graft, n = 2, polytetrafluoroethylene, n = 2) required thrombectomy, with success in three. During a mean follow-up of 49.5 months (range, 4.7 to 137 months), 95 imaging studies were performed (average, five per patient; range, one to 10 studies). Venography detected mild or moderate graft stenosis in seven patients; two progressed to severe stenosis. Two additional grafts developed early into severe stenosis. Four of 19 grafts occluded during follow-up (two polytetrafluoroethylene, two spiral saphenous vein graft). Computed tomography failed to identify stenosis in two grafts, magnetic resonance imaging failed to confirm one stenosis and one graft occlusion, and duplex scanning was inconclusive on graft patency in 10 patients. Angioplasty was performed in all four patients with severe stenosis, with simultaneous placement of Wallstents in two. One of the Wallstents occluded at 9 months. Repeat percutaneous transluminal angioplasty was necessary in two patients, with placement of Palmaz stents in one. Only one graft occlusion and one severe graft stenosis occurred beyond 1 year. The primary, primary-assisted, and secondary patency rates were 61%, 78%, and 83% at 1 year and 53%, 70%, and 74% at 5 years, respectively. Conclusions: Long-term secondary patency rates justify SVC grafting for benign disease. Postoperative surveillance with contrast venography is indicated in the first year to detect graft problems. Endovascular techniques may salvage and improve the patency of SVC grafts. (J Vasc Surg 1998;27:287-301.)

Emergent endovascular treatment for leg ischemia complicating acute aortic dissection

We describe a patient with acute aortic dissection involving the right iliac artery and causing right lower leg ischemia that was successfully treated by Wallstent placement. Emergent endovascular treatment may be the treatment of choice in the patient with acute leg ischemia caused by the involvement of the iliac artery by aortic dissection.

Treatment of a Failed Bifurcated Abdominal Aortic Stent Graft with Thrombolysis and Wallstent Placement

Treatment of a Failed Bifurcated Abdominal Aortic Stent Graft with Thrombolysis and Wallstent Placement