Usefulness of a Guiding Sheath for Fluoroscopic Colorectal Stent Placement

OBJECTIVE: To investigate the technical feasibility, clinical usefulness, and safety of a guiding sheath in fluoroscopic stent placement for patients with malignant colorectal obstructions. MATERIALS AND METHODS: Between June 2007 and January 2011, fluoroscopic placement of a dual colorectal stent was attempted in a total of 97 patients with malignant colorectal obstructions. A polytetrafluoroethylene guiding sheath was used in patients in whom a stent delivery system failed to reach the obstruction. Usefulness of the sheath was evaluated depending on whether the sheath could successfully assist the stent delivery system reach its area of interest. RESULTS: The guiding sheath was needed in 22 patients (15 men, 7 women; age range, 33-77 years; mean age, 59 years). The overall success rate for passing the sheath to the area of interest was 100%. There were no procedure-related deaths or major complications. The majority of the patients reported mild discomfort. In 2 of 22 patients with successful passing of the sheath to the area of interest, stent placement failed because of failure in the negotiation of a guide wire through the obstruction. CONCLUSION: Using a guiding sheath seems to be easy, safe and useful in fluoroscopic stent placement for patients with malignant colorectal obstructions.

Endovascular Stent Placement for the Treatment of Superficial Femoral Artery Stenoses and Occlusions

PURPOSE: The aim of this study was to evaluate effectiveness of an endovascular stent placement in the treatment of superficial femoral artery stenoses and occlusions. MATERIALS AND METHODS: An angioplasty and stent placement was performed in forty four patients (42 men and 2 women; mean age: 71.2 years; age range: 50-82 years). A total of 27 patients were diagnosed with intermittent claudication, in addition to 8 patients with resting pain, and 9 patients with gangrene. A follow-up evaluation accompanied with a physical examination, catheter angiography, and a color Doppler sonography was performed. The patency rates were analyzed after 3 months, 6 months, 1 year and 2 years. The predictors of restenosis, according to the clinical and anatomical classification, risk factors, as well as the correlation of stent fracture and restenosis were analyzed. RESULTS: Initial technical success was achieved in all patients. The stent placement resulted in an initial improvement of the clinical category in more than one level for 95.5% of cases. Over the course of the follow-up period (mean: 17 months; range, 1-106 months), restenosis occurred in 16 patients (36.4%). The highest patency rates were 87.9% after 3 months, 81.5% after 6 months, 78.0% after 1 year, 54.2% after 2 years, and 46.0% after 3 years. No significant difference was found for the patency rates as a function of the clinical and anatomical classifications, or the risk factors. A stent fracture was identified on only two occasions; however, no clinical symptoms or good intra-stent blood flow was observed in a follow-up angiography. CONCLUSION: A mid-term patency after the stent placements for superficial femoral artery stenoses and occlusions was found to be unfavorable despite an initial success rate. Consequently, greater clinical experience and analysis is necessary.

Bronchial stump fistula :treatment with covered retrievable hinged metallic stents-preliminary clinical experience / 介入放射学杂志

Objective To evaluate the preliminaily clinical efficacy and retrievability of a retrievable hinged covered metallic stent in the treatment of the bronchial stump fistula (BSF). Methods Between April 2003 and March 2005, 8 patients with bronchial stump fistula after pneumonectomy or lobectomy were treated with two types (A and B) of retrievable hinged covered metallic stents. Type A stent was placed in 6 patients and type B in 2 under fluoroscopic guidance. The stent was removed with a retrieval set when BSF was healed or complications occurred. Results Stent placement in the bronchial tree was technically successful in all patients, without procedure-related complications. Immediate closure of the BSF was achieved in all patients after the procedure. Stents were removed from all patients but one. Removal of the stents was difficult in two patients due to tissue hyperplasia. Patients were followed up for 6 - 21 months. Placement of the stents remained stable in all patients except one due to severe cough. Permanent closure of BSF was achieved in 7(87.5%) of 8 patients. Conclusion Use of a retrievable hinged covered expandable metallic stent is a simple,safe, and effective procedure for closure of the BSF. Retrieval of the stent seems to be feasible. (J Intervent Radiol, 2007, 16: 253-257)[ Key words ] Fistula, pulmonary; Bronchialpleural fistula; Stents and prostheses; Computed tomography

Interventional Management of Malignant Colorectal Obstruction: Use of Covered and Uncovered Stents

Objective: We wanted to evaluate usefulness of uncovered stent in comparison with covered stent for the palliative treatment of malignant colorectal obstruction. Materials and Methods: Covered (n = 52, type 1 and type 2) and uncovered (n = 22, type 3) stents were placed in 74 patients with malignant colorectal obstruction. Stent insertion was performed for palliative treatment in 37 patients (covered stent: n = 23 and uncovered stent: n = 14). In the palliative group, the data on the success of the procedure, the stent patency and the complications between the two groups (covered versus uncovered stents) were compared. Results: The technical success rate was 89% (33/37). Symptomatic improvement was achieved in 86% (18/21) of the covered stent group and in 92% (11/12) of the uncovered stent group patients. The period of follow-up ranged from three to 319 days (mean period: 116+/-85 days). The mean period of stent patency was 157+/-33 days in the covered stent group and 165+/-25 days in the uncovered stent group. In the covered stent group, stent migration (n = 11), stent fracture (n = 2) and poor expansion of the stent (n = 2) were noted. In the uncovered stent group, tumor ingrowth into the stents (n = 3) was noted. Conclusion: Self-expanding metallic stents are effective for relieving malignant colorectal obstruction. The rate of complications is lower in the uncovered stent group than in the covered stent group.

Efficacy of a Paclitaxel-Eluting Nitinol Stent on the Inhibition of Pseudointimal Hyperplasia in a Transjugular Intrahepatic Portosystemic Shunt: An Experimental Study in a Swine Model

PURPOSE: To evaluate the efficacy of a paclitaxel-eluting nitinol stent on the inhibition of pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt. MATERIALS AND METHODS: Twelve pigs were used in this study. Two types of 10-mm diameter and 60-mm long nitinol stents were made for a transjugular intrahepatic portosystemic shunt by coating them with a polyurethane solution, with and without paclitaxel. Each transjugular intrahepatic portosystemic shunt was created successfully in the 12 swine with 7 paclitaxel-eluting stents and 5 polyurethane stents. Five swine in each group were followed-up for 14 days due to the death of 2 swine given the paclitaxel-eluting stents. The proliferation of the pseudointima was evaluated on both follow-up portograms and histopathology examinations. The mean maximum pseudointimal hyperplasia is expressed as the percentage of the stent radius. RESULTS: On the portograms, all the transjugular intrahepatic portosystemic shunts using the paclitaxel-eluting stents maintained patency despite there being a complete occlusion of the polyurethane stents in all the animals. The histopathology analysis revealed the mean maximum pseudointimal hyperplasia to be 25% and 76% in the paclitaxel-eluting and control stents, respectively. CONCLUSION: A transjugular intrahepatic portosystemic shunt with a paclitaxel-eluting nitinol stent appears to significantly inhibit the formation of pseudointimal hyperplasia.

Noninvasive Assessment of In-Stent Restenosis of the Coronary Artery with Using 16-Slice Computed Tomography

PURPOSE: We strove to evaluate in-stent restenosis of the coronary artery by measuring the in-stent CT attenuation with using 16-multislice CT. MATERIALS AND METHODS: We analyzed the coronary CT angiography, with using 16-slice CT, in 45 stents of 30 patients. The CT attenuation was measured in the lumen of the stented segments and in the lumen of the segment proximal to the stents, and this attenuation was compared with each other. The CT attenuation difference between them was analyzed in relation to the presence of significant in-stent restenosis. Conventional coronary angiography was used as a standard of reference for in-stent restenosis. RESULTS: 12 stents in 12 patients revealed significant restenosis on the conventional coronary angiography. In 6 (50%) of them, the CT attenuation value of the in-stent lumen was lower than that of the proximal segments (373.8 HU vs. 497.1 HU, respectively, p=0.77). In the other 6 stents, a small stent diameter (n=3) and adjacent severe calcification (n=2) accounted for the higher CT attenuation value of the in-stent lumen. In all the stents without significant restenosis, the CT attenuation values of the in-stent lumens were higher than those of their proximal segments. CONCLUSION: The measurement of CT attenuation with using 16-slice CT at the in-stent lumen as compared to the attenuation of the proximal segment provides an objective, confident method for the diagnosis of in-stent restenosis.

Results of Carotid Artery Stenting using Filter Wire in 24 Consecutive Symptomatic Patients with Severe Stenosis

PURPOSE: The aims of this study were to analyze the results of carotid artery stenting using distal protection with FilterWire, and evaluate the effectiveness of FilterWire for distal embolic protection. MATERIALS AND METHODS: Between June and December in 2004, elective carotid artery stenting using FilterWire was attempted in 25 lesions of 24 consecutive patients. All patients were symptomatic, with recurrent transient ischemic attacks (TIA) or a stroke. The cerebral ischemic lesions of embolic origin were evaluated before and after the procedure using magnetic resonance imaging, including diffusion-weighted images. Both pre- and post-procedural 99mcTc-ECD SPECT were performed to assess the cerebral blood flows. Any visible debris within the FilterWire was sent for histological/cytological analyses. RESULTS: Technical success was achieved all 25 cases. The mean pre-procedural stenosis was 89% (range 70-100%), and that immediately after stent placement was nearly 0%. With the exception of only one major stroke (1/25, 4%), no periprocedural complications were encountered. On the diffusion weighted images, new lesions were observed in four patients (4/25, 16%), but these were clinically silent. FilterWire-related transient spasm occurred in eight of the 25 procedures (32%). CONCLUSION: Carotid artery stenting, with FireWire distal protection, seems technically feasible, safe and effective in preventing procedural related embolic complications.

Diagnosis of Arteriovenous Fistulas following a Lumbar Discectomy

PURPOSE: To evaluate the relevant clinical and radiographical findings for the diagnosis of an arteriovenous fistula after a lumbar discectomy. MATERIALS AND METHODS: Five patients with an arteriovenous fistula following a lumbar discectomy were preoperatively diagnosed and treated. We retrospectively evaluated the level of surgery, injured vessels, clinical symptoms, physical findings, and the interval between surgery and treatment. Effective and fast diagnostic methods for determining the presence of a postoperative arteriovenous fistula were evaluated. RESULTS: All of the arteriovenous fistulas resulted from operative injuries of the iliac arteries and veins. They were diagnosed after a mean time of 22 months (range 2 months-4 years) in spite of various symptoms and signs shortly after surgery. The arteriovenous fistulas were confirmed with angiography and were treated by surgery for 3 patients and by insertion of a stent-graft in 2 patients. Postoperative CT angiography showed the complete occlusion of the fistula tract and the normal blood flow. CONCLUSION: Essential clinical information and radiological examination, especially CT angiography with 3D reconstruction, is necessary to obtain to diagnose an arteriovenous fistula after a lumbar discectomy.

Primary Stent Placement for Chronic Spontaneous Infrarenal Abdominal Aortic Dissection: A Case Report

Spontaneous infrarenal abdominal aortic dissection (SIAAD) is a rare entity with various clinical presentations. We recently encountered the even rarer condition of a female patient suffering from chronic SIAAD with multiple intimal flaps and prominent lumbar artery collaterals; this all caused stenotic changes of the infrarenal abdominal aorta and produced progressive lower extremity pain and claudication in both her legs. This patient's condition was successfully managed by primary stent placement followed by balloon angioplasty.

Endovascular Stent-Graft Placement and Secondary Intervention for Abdominal Aortic Aneurysm in a Patient who had a Previously Inserted Iliac Stent

Endovascular repair of abdominal aortic aneurysm is associated with low morbidity and mortality rates when compared to open surgery, and this can be used in patients who are at a high risk for open surgical repair. Also, secondary intervention is an important for achieving intermediate and long term success of endovascular repair of abdominal aortic aneurysm as this can resolve complications. We report here on endovascular stent-graft placement and a secondary interventional procedure in the abdominal aortic aneurysm of a patient who had a previously inserted iliac stent.

3D Multislice CT Angiography in Post-Aortic Stent Grafting: A Pictorial Essay

Helical CT angiography has been widely used in both pre- and post-aortic stent grafting and it has been confirmed to be the preferred modality when compared to conventional angiography. The recent development of multislice CT (MSCT) has further enhanced the applications of CT angiography for aortic stent grafting. One of the advantages of MSCT angiography over conventional angiography is that the 3D reconstructions, based on the volumetric CT data, provide additional information during follow-up of aortic stent grafting. While endovascular repair has been increasingly used in clinical practice, the use of 3D MSCT imaging in endovascular repair continues to play an important role. In this pictorial essay, we aimed to discuss the diagnostic performance of 3D MSCT angiography in post aortic stent grafting, including the most commonly used surface shaded display, curvilinear reformation, the maximum intensity projection, volume rendering and virtual endoscopy. The advantages and disadvantages of each 3D reconstruction are also explored.

Complications after Endovascular Treatment

Endovascular treatment has rapidly progressed due to the improvements of the equipment and endovascular devices. Continual refinement of the technology and techniques associated with endovascular treatment has led interventionists to perform more complicated endovascular treatment. However, the numerous complications of endovascular treatment are now well recognized and described in the literature. This article reviews various complications of three main endovascular treatments: balloon angioplasty, stent or stent-graft placement, and catheter-directed thrombolysis.

Endovascular Therapy of Left Subclavian Artery Stenosis in Patients with Left Internal Mammary-Coronary Artery Bypass Graft

PURPOSE: We wanted to evaluate the clinical usefulness of percutaneous transluminal angioplasty (PTA) and stenting of left subclavian artery (LSA) stenosis in the patients with a left internal mammary artery (LIMA)-coronary artery bypass graft. MATERIALS AND METHODS: From September 1998 to November 2005, significant proximal LSA stenoses were treated with PTA and stenting in 22 patients (15 men and 7 women) who had a prior LIMA-coronary artery bypass graft or who were willing to undergo LIMA-coronary artery bypass grafting. The technical success rates, complications and restenosis during the follow-up period were retrospectively evaluated. RESULTS: Six patients had a prior LIMA bypass graft and 16 patients were treated before their coronary artery bypass surgery. The etiology of the LSA stenosis was atherosclerosis in all patients. Four patients were treated with PTA only, and stents were placed in 18 patients. Technical success was achieved in all patients. An embolism in the proximal LIMA occurred after stenting in one patient, and the LIMA was recanalized with transcatheter thrombolysis. During a mean follow-up of 30 months, only one patient was found to have recurrent LSA stenosis 29 months after stenting and this patient was successfully managed with angioplasty. CONCLUSION: Endovascular therapy is useful and efficacious for the treatment of LSA stenosis in patients with a LIMA-coronary artery bypass graft.

Spontaneous Rupture of the Left Common Iliac Vein: Management with Surgical Repair and Endovascular Stent

We report here on a case of spontaneous rupture of the left common iliac vein that was diagnosed preoperatively with computed tomography (CT), and the patient was successfully treated with surgery and stent placement. A 60-year-old woman was referred to our emergency room because of sudden left lower abdominal pain and swelling of the left lower extremity. CT revealed a huge retroperitoneal hematoma and extrinsic compression of the left common iliac vein with acute thrombosis of the deep veins of the left lower extremity. Venous patch angioplasty was performed at the site of spontaneous rupture. After performing thrombectomy with using a Forgaty catheter, a stent was placed at the occluded segment of the left common iliac vein under C-arm fluoroscopic guidance. The follow-up CT scans taken at 10 days and 8 months after the initial examination demonstrated a venous stent with preserved luminal patency and the striking resolution of the deep vein thrombosis of the left lower extremity.

Radioisotope Treatment for Benign Strictures of Non-vascular Luminal Organs / 핵의학분자영상

Tissue hyperplasia is one of the most frequently encountered complications when self-expanding metallic stents are placed in benign non-vascular luminal organ strictures, thus causing restenosis of the lumen. The investigators postulated that ionizing irradiation could be applied to prevent restenosis caused by tissue hyperplasia in non-vascular luminal organs as it reduced coronary or peripheral arterial narrowing successfully. The authors combined beta-irradiation using 188Re-MAG3 solution with balloon dilation for animal and clinical studies because this new treatment approach had the advantages such as low penetration depth of beta-ray, self-centering irradiation, and mechanical effect of balloon dilation over using gamma-irradiation with afterloading devices. In this article, the concept and mechanism of radioisotope balloon dilation, and animal and clinical studies using radioisotope balloon dilation are reviewed.

Metallic Stent Placement in Hemodialysis Graft Patients after Insufficient Balloon Dilation

OBJECTIVE: We wanted to report our experience of metallic stent placement after insufficient balloon dilation in graft hemodialysis patients. MATERIALS AND METHODS: Twenty-three patients (13 loop grafts in the forearm and 10 straight grafts in the upper arm) underwent metallic stent placement due to insufficient flow after urokinase thrombolysis and balloon dilation. The indications for metallic stent deployment included 1) recoil and/or kinked venous stenosis in 21 patients (venous anastomosis: 17 patients, peripheral outflow vein: four patients); and 2) major vascular rupture in two patients. Metallic stents 8-10mm in diameter and 40-80 mm in length were used. Of them, eight stents were deployed across the elbow crease. Access patency was determined by clinical follow-up and the overall rates were calculated by Kaplan-Meier survival analysis. RESULTS: No procedure-related complications (stent fracture or central migration) were encountered except for a delayed Wallstent shortening/migration at the venous anastomosis, which resulted in early access failure. The overall primary and secondary patency rates (+/- standard error) of all the vascular accesses in our 23 patients at 3, 6, 12 and 24 months were 69% +/- 9 and 88% +/- 6, 41% +/- 10 and 88% +/- 6, 30% +/- 10 and 77% +/- 10, and 12% +/- 8 and 61% +/- 13, respectively. For the forearm and upper-arm grafts, the primary and secondary patency rates were 51% +/- 16 and 86% +/- 13 vs 45% +/- 15 and 73%+/-13 at 6 months, and 25% +/- 15 and 71% +/- 17 vs 23% +/- 17 and 73% +/- 13 at 12 months (p = .346 and .224), respectively. CONCLUSION: Metallic stent placement is a safe and effective means for treating peripheral venous lesions in dialysis graft patients after insufficient balloon dilation. No statistically difference in the patency rates between the forearm and upper-arm patient groups was seen.

Outcome of Endovascular Treatment in Symptomatic Intracranial Vascular Stenosis

OBJECTIVE: The outcome evaluation for the revascularization of intracranial vascular stenoses has not been fully described due to the highly technical nature of the procedure. We report here on the early and late clinical outcomes of angioplasty and/or stenting of symptomatic severe intracranial vascular stenoses at a single institute. MATERIALS AND METHODS: Since 1995, we have treated 35 patients with symptomatic intracranial vascular stenosis (more than 70% stenosis, mean stenosis: 78.6%+/-6.2%). An gioplasty (n = 19) was performed for the horizontal segment of the middle cerebral artery (M1) (n = 16) and the basilar artery (BA) (n = 1), the intradural vertebral artery (VA) (n = 1), and the cavernous internal carotid artery (ICA) (n = 1). Stenting (n = 16) was performed for the cavernous or petrous ICAs (n = 9), the intradural VA (n = 3), BA (n = 2), and M1 (n = 2) artery. We assessed the angiographic success (defined as residual stenosis < 50%) rate, the periprocedural complications during the 30-day periprocedural period, the symptomatic recurrence and restenosis during a mean 22-month follow-up (FU) period. The Kaplan-Meier estimate of the cumulative event-free rate of the major cerebrovascular events, i.e. death, stroke or restenosis, was also done. RESULTS: Angiographic success was achieved in 97% of our patients (34/35). There were four procedure-related complications (11%) including a death and a minor stroke. During the mean 22-month FU, the asymptomatic restenosis rate was 9% and the symptomatic restenosis rate was 6% in the target lesion and 9% in all the vascular territories. The Kaplan-Meier estimate was 70.6% (95% confidence interval = 46.5-94.7) after 33 months of FU. CONCLUSION: In addition to a high angiographic success rate and an acceptable periprocedural complication rate, intracranial angioplasty and/or stenting revealed a relatively low symptomatic recurrence rate. Hemorrhage is a rare, but the physician must aware that potentially fatal periprocedural complications can occur.

Influence of a Paclitaxel-eluting Expandable Metallic Stent on Tissue Hyperplasia: An Experimental Study in a Canine Tracheal Model

PURPOSE: To evaluate the efficacy of a paclitaxel-eluting expandable metallic stent in reducing tissue hyperplasia following stent placement in a canine tracheal model. MATERIALS AND METHODS: Nine paclitaxel-eluting stents (drug stent, DS) consisting of a proximal bare part and a distal polyurethane-covered part were placed in the trachea of nine dogs and nine control stents (control stent, CS) were placed in the other nine dogs. The dogs were scheduled to be sacrificed 12 weeks after stent placement. Gross and histological factors, such as epithelial erosion/ulcer, granulation tissue thickness and inflammatory cell infiltration were evaluated after each dog was sacrificed. RESULTS: There were no procedure-related complications or malpositioning of any of the stents. One CS migrated less than eight weeks following stent placement. Four dogs (one DS and three CS dogs) died between three and five weeks following stent placement. Therefore, pathologic specimens were obtained from eight DS and five CS dogs. Epithelial erosion/ulcer or inflammatory cell infiltration was slightly more prominent in the DS cases than in the CS cases, in both the bare part and the covered part. However, the data was not statistically significant. Granulation tissue thickness was lower in the DS cases than in the CS cases in both the bare part (mean, 3.63-mm vs. 4.37-mm) and the covered part (mean, 1.75-mm vs. 2.78 mm), but the data was also statistically insignificant. CONCLUSION: Although the data was not statistically significant, placement of paclitaxel-eluting expandable metallic stent demonstrates a tendency toward a decrease in granulation tissue thickness in canine tracheal models.

Treatment of Malignant Gastroduodenal Obstruction with Using a Newly Designed Complex Expandable Nitinol Stent: Initial Experiences

PURPOSE: We wanted to evaluate the usefulness of a new type of a complex expandable nitinol stent that was designed to reduce the stent's propensity to migration during the treatment of malignant gastroduodenal obstructions. MATERIALS AND METHODS: Two types of expandable nitinol stent were constructed by weaving a single thread of 0.2 mm nitinol wire in a tubular configuration: an uncovered stent 18mm in diameter and a covered stent 16mm in diameter. Both ends of the covered stent were fabricated by coaxially inserting the covered stent into the tubular uncovered stent and then attaching the two stents together with using nylon monofilament. Under fluoroscopic guidance, the stent was placed in 29 consecutive patients (20 men and 9 women, mean age: 65 years) who were suffering with malignant gastric outlet obstruction (n=20), duodenal obstruction (n=6) or combined obstruction (n=3). Clinical improvement was assessed by comparing the food intake capacity before and after the procedure. The complications were investigated during the follow up period. RESULTS: Stent placement was successful in all the patients. After stent placement, the symptoms improved in all but one patient. During the follow up, stent migration occurred in one patient (3%) at 34 days after the procedure. Despite the stent migration, the patient was able to resume a soft diet. Six patients developed recurrent symptoms of obstruction with tumor overgrowth at a mean of 145 days after the procedure; all the patients underwent coaxial placement of an additional stent with good results. One patient showed recurrence of obstruction due to tumor in-growth, and this was treated by placement of a second stent. Two patients with stent placement in the duodenum suffered from jaundice 26 days and 65 days, respectively, after their procedures. CONCLUSION: Placement of the newly designed complex expandable nitinol stent seems to be effective for the palliative treatment of malignant gastroduodenal obstructions. The new stent also seems to help overcome the disadvantage of the increased migration observed for the covered stent.

An Experience with Placement of a Stent-Graft in a Renal Artery Aneurysm via the Brachial Artery: A Case Report

We introduce here our case of a 4-cm, large saccular aneurysm in a patient with right flank pain that was treated by placement of a stent-graft via the left brachial artery. The large renal artery aneurysm was successfully occluded without any permanent sequela, although there were several complications that included intraprocedural renal arterial thrombosis, occlusion of the posterior segmental artery, a small thromboembolism in the left pons and a small arteriovenous fistula in the brachial artery. Stent-graft placement for treatment of renal arterial aneurysm is an effective and safe procedure, but the operator has to be cautious not to induce complications in case of using the brachial arterial approach.