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.

Parallel Wire Balloon Angioplsty for Undilatable Venous Stenosis in Hemodialysis Fistula

PURPOSE: The purpose of this study was to assess the value of the parallel wire balloon angioplasty technique for treating dysfunctional hemdialysis fistula with rigid stenosis, and this type of lesion was resistant to conventional angioplasty. MATERIALS AND METHODS: Between March 2002 and August 2003, we included 6 patients (mean age: 59, males: 2, females: 4) who were treated via parallel the wire balloon angioplasty technique and their hemodialysis fistula has stenoses that were resistant to conventional angioplasty. We performed conventional angioplasty in all patients, but we failed to achieve sufficient dilatation. In the cases of highly resistant stenosis, an additional 0.016 inch wire was inserted into the 7 F vascular sheath. During angioplasty, a 0.016 inch guide wire was inserted between the balloon and the stenosis and then it was pushed to and fro until the balloon indentation disappeared. After the procedure, we performed angiography to identify the residual stenosis and the procedure-related complications. RESULTS: The undilatable stenoses in 5 patients were successfully resolved without complications via the parallel wire angioplasty technique. In one patient, indentation of balloon was not resolved, but the residual stenosis was both minimal and hemodynamically insignificant. CONCLUSION: The parallel wire angioplasty technique seems to be a feasible and cost-effective method for treating a dysfunctional hemodialysis fistula with undilatable and rigid stenosis.

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.

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.

Angioplastia com implante de "stent" na artéria mesentérica superior / Superior mesenteric artery stent following percutaneous transluminal angioplasty

Endovascular techniques have been used to treat arterial stenosis throughout the vascular system. The goal of this work is to report one case of percutaneous transluminal angioplasty with primary stenting of the ostial segment of the superior mesenteric artery for treatment of chronic mesenteric ischemia.

The Usefulness of Percutaneous Transluminal Angioplasty of the Middle Cerebral Artery Stenosis in Patients with Transient Ischemic Attack

PURPOSE: To determine the effectiveness of percutaneous transluminal angioplasty(PTA) of atherosclerotic middle cerebral artery(MCA) stenosis in patients with transient ischemic attack(TIA). MATERIALS AND METHODS: Ten patients with TIA who had undergone PTA were retrospectively investigated. In all ten, angiography revealed stenosis of the MCA. Mechanical dilatation was performed at the stenotic portion, and the angiographic findings after PTA, as well as peri/post-angioplastic complications, were evaluated. Four to 64 (mean, 23.5) months later, neurologic symptoms and the nature and timing of recurrent attacks were also assessed. RESULTS: The degree of stenosis before PTA was 50-75% in six patients and greater than 75% in four. Complete or partial angiographic recanalization of the stenotic segment occurred in nine patients (90%). During follow-up, seven patients recovered without recurrent TIA or cerebral stroke; one reported a tingling sensation and one experienced vertebrobasilar insufficiency. Motor aphasia developed in one patient after PTA, but after systemic heparinization, improved within 24 hours. One patient who suffered intracranial hemorrhage due to vascular rupture during PTA did three days later. CONCLUSION: PTA for atherosclerotic MCA stenosis in patients with TIA is an effective therapeutic method.

Radiologic Management of Hepatic Arterial Stenosis or Thrombosis Following Liver Transplantation

PURPOSE: To assess the results and usefulness of interventional procedures for hepatic arterial stenosis or thrombosis following liver transplantation. MATERIALS AND METHODS: During the past five years, eight patients aged 1-59 (mean, 39) years among 187 liver transplant recipients showed elevated of liver enzyme levels (AST/ALT) and decreased arterial flow at Doppler ultrasound. Hepatic arteriography revealed luminal stenosis or occlusion at the proper hepatic artery, and six patients, one of whom required thrombolysis before the procedure, underwent percutaneous transluminal angioplasty (PTA) using a balloon. In two with thronbosis, thrombolysis without PTA was performed. In order to increase hepatic arterial flow, four patients underwent additional coil embolization of the gastroduodenal or splenic artery. RESULTS: Hepatic arterial flow recovered in all six patients after PTA. Three required repeat PTA for restenosis and one of these needed stent placement after repeated PTA. At follow-up, 6-17 months later, the three had good hepatic function. Within four days, the other three expired due to graft failure, hepatorenal syndrome and sepsis. One of the patients who underwent thrombolysis without PTA expired and the other required retransplantation. In this case there were no procedure - related complications. CONCLUSION: Radiologic interventions are useful for treatment of hepatic arterial stensis or thrombosis in patients with liver transplantations.

Treatment of Internal Carotid Artery Dissections with Endovascular Stent Placement: Report of Two Cases

Extracranial carotid artery dissection may manifest as arterial stenosis or occlusion, or as dissecting aneurysm formation. Anticoagulation and/or antiplatelet therapy is the first-line treatment, but because it is effective and less invasive than other procedures, endovascular treatment of carotid artery dissection has recently attracted interest. We encountered two consecutive cases of traumarelated extracranial internal carotid artery dissection, one in the suprabulbar portion and one in the subpetrosal portion. We managed the patient with suprabulbar dissection using a self-expandable metallic stent and managed the patient with subpet-rosal dissection using a balloon-expandable metallic stent. In both patients the dissecting aneurysm disappeared, and at follow-up improved luminal patency was observed.

Effect of Percutaneous Transluminal Angioplasty in insufficiency of Arteriovenous Fistula for Hemodialysis

PURPOSE: To evaluate the effectiveness of percutaneous transluminal angioplasty(PTA) and to determine thefactors affecting the long-term patency rate in the management of insufficient hemodialytic arteriovenousfistula(AVF). MATERIALS AND METHODS: Forty-nine cases of insufficient hemodialytic AVF were treated in 44patients(native AVF:20, graft AVF:29, M:17, F:27, Age:22-70 years). In 28 thrombus patients, thrombolysis wasperformed with urokinase, and was followed by PTA. The initial success rate and complications of PTA wereevaluated. According to the site and length of the stenosis, type and age of the AVF, the presence or abscence of thrombus, a history of diabetic mellitus, the patient 's age, and the duration of renal failure, patency rateswere compared within each subgroup using the Kaplan-Meier logrank test. RESULTS: The initial success rate of PTAfor insufficient hemodialytic AVF was 88%(43/49), the patency rate of PTA was 67% at 6 months, and 50% at 12months. The initial success rate of thrombolysis was 89%(25/28). The complication rate of PTA was 12%(6/49), ofwhich five cases were vein rupture, and one was subcutaneous hematoma. Statistically, the patency rates in theabove mentioned subgroups were not significantly different. CONCLUSION: PTA with or without thrombolysis offerssafe and effective management of insufficient hemodialytic AVF.

Usefulness of CT Angiogra p hy after Metallic Stent Implantation of the Internal Carotid Artery

PURPOSE: To evaluate the usefulness of CT angiography in Patients with implantation of metallic stent for stenosed internal carotid artery. MATERIALS AND METHODS: Seven patients with atherosclerotic stenosis of the internal carotid artery underwent metallic stent implantation. All were male and their ages ranged from 36 to 69 years. A total of seven stents were placed in the internal carotid artery in five patients and in the carotid bifurcation in two. Spiral CT scans were obtained and CT angiographic images were reconstructed using MPR or curved MPR techniques at a workstation. The interval between CT and conventional angiography did not exceed six days except in one patient, in whom it was 61days. CT and conventional angiography were compared for stent position with respect to the carotid bifurcation, stent deformation, intraluminal filling defect, and luminal caliber and outflow. Luminal patency of the implanted stent was measured according to NASCET(North American Symptomatic Carotid Endarterectomy Trial) criteria, and statistically processed (p<.05). The presence or absence of intrastent thrombus and vascular wall calcification was determined using axial source images. RESULTS: In all patients, CT angiographic findings matched those obtained by conventional angiography. Complications such as migration or deformation of an implanted stent, intraluminal filling defect, change of luminal caliber or outflow of implanted stent were not observed in any patient. In two studies in which Wilcoxon signed rank test was used, degree of stent expansion correlated closely(p=0.237). Axial source images showed that in no patient was an intrastent thrombus present, though in five, vascular wall calcification of internal carotid arteries outside the stent was noted. CONCLUSION: CT angiography is useful for the assessment of positional change, occlusion, and luminal patency of a stent-implanted internal carotid artery.

Percutaneous Transluminal Angioplasty of Chronic Arterial Occlusive Disease below the Knee Joint

PURPOSE: The purpose of this study was to determine the safety and efficacy of the percutaneous transluminal angioplasty(PTA) in patients with chronic arterial occlusive disease below the knee joint. MATERIALS AND METHODS: We retrospectively analyzed the results of 36 procedures in 16 patients. There were 15 men and one woman, aged 57-75 years(mean, 62 years). Indications were disabling claudication(SVS/ISCVS grade 1, category 3) in five cases, rest pain(grade 2, category 4) in three cases, and non-healing ulceration or gangrene(grade 3, category 5) ineight cases. PTA was performed by using small vessel balloon catheter of 2-4 mm and 3 mm monorail balloon catheterin tibioperoneal vessels and 5-6 mm balloon catheter in distal popliteal artery and tibioperoneal trunk. Combined thrombolytic therapy with Urokinase was performed in 14 patients. RESULTS: Involved infrapopliteal vessels werefour distal popliteal arteries, 15 tibioperoneal trunks, six anterior tibial arteries, five posterior tibialarteries, and seven peroneal arteries. Technical success was determined when post-PTA angiogram showed less than 30% of residual stenosis. Clinical success was defined as improvement of clinical symptoms, such as disappearance of claudication or rest pain, and healing of ulceration. Technical success was achieved in 30 of 36 arteries(83%). Clinical success was achieved in 12 of 16 patients(75%) at an average follow-up of 13.3 months(range, 2-46 months). Clinical success rate was 100% in grade 1 category 3 patients, 67% in grade 2 category 4 patients, and 63% in grade 3 category 5 patients. Complication included two distal emboli, one vessel rupture, one vessel thrombosis, and one occluding intimal flap. CONCLUSION: PTA was an effective method for treatment of chronicarterial occlusive disease below the knee joint and considered as the procedure of first choice. Severe claudicant(grade 1) should be included in the indication of the tibioperoneal PTA.

An Experimental Study on the Influence of New Spiral Stent(Hanaro) on the Vascular Structures

PURPOSE: The purpose of this study was to evaluate basic experimental data for the clinical application of a self-expandable stainless steel intravascular Hanaro spiral stent. MATERIALS AND METHODS: For evaluation of thephysical properties of the Hanaro stent, hoop strength, radioopacity, longitudinal flexibility, and foreshortening were measured. Twelve intravascular Hanaro spiral stents were placed in the infrarenal abdominal aorta (n=6) and comon iliac artery (n=6) in six mongrel dogs. Angiography and light microscopic examination were performed after one, two and eight months of placement of the stents. RESULTS: The stent had good radioopacity and was deployed with minimal foreshortening. Hoop strength of a 6mm-interval bend was found to be superior to that of 8mm- and 10mm-bend stent. On angiography the patency rate and thrombosis rate were 100% and 0% in the abdominal aorta and 50% and 50% in the common iliac artery, respectively. Minimal corrosion was seen in all stents, and they appearedto be biocompatible. The stent wires were covered with well-developed neointima which after one month had mostly fibroblast and collagen tissue; the thickness of the neointima increased gradually during a period of eightmonths. At the end of that period, collagen fibres in the neointima were denser and showed a more paralled configuration than at one month. CONCLUSION: The Hanaro stent has good physical properties and also has a high patency rate, and good biocompatibilities. The stent may therefore be reliably and safely deployed in the humanvascular system.