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Purpose: To evaluate the technical and clinical success rates of percutaneous stent revascularization in the treatment of chronic mesenteric ischemia (CMI)., Patients and Methods: 17 patients (12 female) with typical symptoms of CMI were treated by percutaneous stent placement for stenoses of the splanchnic arteries (celiac trunk; superior mesenteric artery, SMA; inferior mesenteric artery, IMA). The primary and secondary technical success, primary and secondary clinical success, and the long-term clinical outcome were determined., Results: A total of 24 stents were implanted in 21 splanchnic arteries (12 stents in the celiac trunk, 11 in the SMA and 1 in the IMA). The primary technical success rate was 91% (19/21 arteries), the secondary technical success rate was 95% (21/22 arteries). Clinical follow-up was available for 16 patients. The primary clinical success rate was 81% (13/16 patients). Following two secondary interventions, the secondary clinical success rate was 94% (15/16 patients). Long-term clinical success was achieved in 15 of 16 patients (94%) with a mean follow-up of 26 months. One patient died within 30 days of the intervention and two patients demonstrated major complications (1 dissection, 1 stent dislocation). None of the patients required surgical revascularization and none of the patients died due to recurrent mesenteric ischemia., Conclusion: Percutaneous stent placement for the treatment of CMI can be performed with a high technical and clinical success rate as well as an excellent long-term clinical outcome.

Background: Carotid endarterectomy (CEA) has been shown to be effective in stroke prevention for patients with symptomatic or asymptomatic carotid artery stenosis. Although several prospective randomized trials indicate that carotid artery stenting (CAS) is an alternative but not superior treatment modality, there is still a significant lack of long-term data comparing CAS with CEA. This study presents long-term results of a prospective, randomized, single-center trial., Methods: Between August 1999 and April 2002, 87 patients with a symptomatic high-grade internal carotid artery stenosis (>70%) were randomized to CAS or CEA. After a median observation time of 66 +/- 14.2 months (CAS) and 64 +/- 12.1 months (CEA), 42 patients in each group were re-evaluated retrospectively by clinical examination and documentation of neurologic events. Duplex ultrasound imaging was performed in 61 patients (32 CAS, 29 CEA), and patients with restenosis >70% were re-evaluated by angiography., Results: During the observation period, 23 patients (25.2%) died (10 CAS, 13 CEA), and three were lost to follow up. The incidence of strokes was higher after CAS, with four strokes in 42 CAS patients vs none in 42 CEA patients. One transient ischemic attack occurred in each group. A significantly higher rate of restenosis >70% (6 of 32 vs 0 of 29) occurred after CAS compared with CEA. Five of 32 CAS patients (15.6%) presented with high-grade (>70%) restenosis as an indication for secondary intervention or surgical stent removal, and three presented with neurologic symptoms. No CEA patients required reintervention (P < .05 vs CAS). A medium-grade (<70%) restenosis was detected in eight of 32 CAS patients (25%) and in one of 29 CEA patients (3.4%). In five of 32 CAS (15.6%) and three of 29 CEA patients (10.3%), a high-grade stenosis of the contralateral carotid artery was observed and treated during the observation period., Conclusion: The long-term results of this prospective, randomized, single-center study revealed a high incidence of relevant restenosis and neurologic symptoms after CAS. CEA seems to be superior to CAS concerning the development of restenosis and significant prevention of stroke. However, the long-term results of the ongoing multicenter trials have to be awaited for a final conclusion.

A 68-year-old lady was admitted to a primary care centre with abdominal pain. She presented with a tender abdomen and a lipase level of 29 456 U/L. Cholecystectomy had been performed in 1971. Because her clinical state worsened the patient was transferred to our intensive care unit. Computed tomography and contrast ultrasound revealed necrotising pancreatitis. Antibiotics were started immediately. 10 days later the patient became febrile and an area of liquid necrosis between the spleen and the left kidney was drained under sonographic guidance by a 12 Fr pigtail. Every ten days the drain was replaced by a larger one. ERCP revealed a communication between the pancreatic duct and the growing necrotic cavity. A 7 Fr/ 7 cm plastic stent was put in. After 30 days an unsuccessful endoscopic necrosectomy was attempted with the cholangioscope through a 28 Fr peel-away sheath. In a further session an effective percutaneous necrosectomy was possible through a laparascopy trocar with a standard gastroscope. The patient became afebrile and signs of infection decreased. The persisting communication between the pancreatic duct and the necrotic cavity was closed with onyx. In the following days the dimensions of the necrotic cavity decreased rapidly. Finally the patient could be discharged home in good health. Antibiotics were stopped and the percutaneous drain was taken out after some weeks of ambulatory care.

Background: Delayed visceral arterial hemorrhage caused by inflammatory vessel erosion represents a rare but life-threatening complication after pancreatic head resection. Therapeutic options include reoperation or endovascular minimally invasive techniques such as embolization or stent graft placement. The present article describes our experiences with implantation of newly developed low-profile stent grafts., Methods: The findings of four patients with delayed visceral arterial hemorrhage are described. All patients were treated with placement of low-profile stent grafts. The patients' medical records, radiological reports, and images were retrospectively reviewed. Technical success was defined as immediate cessation of hemorrhage. Clinical success was defined as hemodynamic stability., Results: A total of seven stent grafts were implanted in four arteries. In detail, one stent graft was placed in the splenic artery of the first and second patients. In the third patient one stent graft was initially implanted in the common hepatic artery. The patient developed recurrent hemorrhages of the common hepatic artery, treated one time surgically and two times by deployment of a second and third stent graft. In the fourth patient two stent grafts were placed in the proper hepatic artery. Technical and clinical success was achieved at every procedure. Apart from recurrent hemorrhage of patient No. 3 there were no major complications., Conclusions: Minimally invasive therapy using low-profile stent grafts is an effective and safe procedure for the treatment of delayed visceral arterial hemorrhage following Whipple's procedure. The technique is a promising alternative to standard procedures such as surgical repair or embolization.

In vitro study to investigate the suitability of contrast enhanced magnetic resonance angiography (CEMRA) for determination of stent patency and grading of in-stent stenoses in 10 metallic stents. The Acculink carotid, DynaLink, Easy Wallstent, JostentSelfX XF, Luminexx, Omnilink, sinus-SuperFlex, SMART, Symphony and ZA stent were separately placed in a vascular phantom. Dedicated stenoses inside the stents generated a concentric lumen narrowing of 50%. CEMRA was performed for each stent. Signal loss inside the stents and artificial lumen narrowing were assessed objectively using the evaluation software of the MR imager. Moreover, three blinded observers determined visibility of stent patency and in-stent stenoses subjectively on a 3-point scale and graded in-stent stenoses. Loss of signal intensity within the stent lumen ranged between 90% (Wallstent) and 5% (ZA), artificial lumen narrowing between 56% (Symphony) and 22% (ZA). For the Symphony and Wallstent, visibility of patency and in-stent stenoses was impaired and the observers' grading exaggerated the degree of stenoses (by 23% and 33%, respectively). For the remainder of stents, patency and stenoses were visible and stenoses were graded accurately (less than 10% discrepancy from reference standard). In this in vitro study, eight of 10 stents presented with MRI characteristics which enabled determination of stent patency and accurate grading of clinically relevant in-stent stenoses.

Objective: Our study was a prospective in vivo study to evaluate whether MR angiography is suitable for assessing stent patency and grading in-stent stenoses and to examine whether the accuracy of MR angiography changes with time after stent implantation., Subjects and Methods: In a prospective study, 34 iliac stenoses in 27 patients were treated by implantation of 35 nitinol stents. MR angiography was performed immediately after stent placement for 32 stents, and both digital subtraction angiography (DSA) and MR angiography were repeated at the 6-month follow-up for 23 stents. Three blinded observers assessed stent patency and the degree of in-stent stenoses on MR angiography and DSA (the standard of reference) images. The difference between the observers' grading of stenoses on DSA and on MR angiography was determined. Statistical analysis was performed using the Student's t test for paired samples., Results: Stent patency was assessed correctly for all stents and both sets of MR angiography images. Evaluation of DSA 1 images (obtained at end of implantation procedure) revealed that 96.9% of in-stent stenoses were less than 50%. On DSA 2 images (obtained at follow-up), 95.7% of in-stent stenoses were graded as less than 50%. The difference between grading of stenoses on DSA and MR angiography images was 15.0% +/- 16.0% (minimum, 0.0%; maximum, 63.3%) for DSA 1 versus MR angiography 1 (statistically significant, p = 0.037) and 9.8% +/- 13.5% (minimum, 0.0%; maximum, 63.3%) for MR angiography 2 versus DSA 2 (not statistically significant, p = 0.355)., Conclusion: Patency was correctly assessed for all stents on MR angiography. The quality of MR angiography regarding characterization of in-stent stenoses improved with time after stent placement. However, discrepancies of more than 60% between grading of lumen narrowing on DSA and MR angiography images occurred even at the 6-month follow-up. Thus, MR angiography is not yet a reliable technique for characterization of in-stent stenoses.

Purpose: Contrast material-enhanced magnetic resonance (MR) angiography is increasingly used in postinterventional imaging after implantation of endovascular stents. The main limitations are stent-related artifacts compromising the visibility of the stent lumen. The aim of this in vivo study is the evaluation of contrast-enhanced MR angiography imaging characteristics of the carotid Wallstent., Materials and Methods: The carotid arteries of 29 patients were examined with contrast-enhanced MR angiography 3-6 days and/or 7-23 months after implantation of a carotid Wallstent into the internal carotid artery. Images were evaluated with regard to the diameter and signal intensity (SI) of the visible stent lumen. Digital subtraction angiography (DSA) was used as the standard of reference., Results: Stent-related artifacts on contrast-enhanced MR angiography caused an artificial lumen narrowing and a reduction of the SI within the stent. Artifacts were pronounced on imaging 3-6 days after stent implantation, but 68% of stents imaged 7-23 months after stent implantation presented with a significantly decreased artificial signal reduction and an improved visibility of the stent lumen., Conclusions: The results of this study indicate that a reliable evaluation of the stent lumen is limited as a result of an artificial decrease of the SI inside the stent. However, in follow-up examinations 7-23 months after stent implantation, visibility of the stent lumen was improved and diagnostic reliability of contrast-enhanced MR angiography was markedly increased. A probable explanation for this phenomenon might be the formation of a neointimal layer covering the stent struts and thereby reducing stent-related artifacts.

Purpose: To evaluate the effectiveness, safety, and short-term patency rates of a self-expandable nitinol stent (JostentSelfX; Abbott Laboratories, Chicago, IL) for treatment of iliac artery stenoses., Materials and Methods: In a prospective study, 34 chronic iliac artery stenoses were primarily treated in 27 patients (mean age, 61.7 years +/- 9.4) by placement of a JostentSelfX. Handling and visibility of the stent was scored on a 4-point scale. Before stent placement, within 3 days after stent placement and at 6 months follow-up, the clinical history, clinical stage according to the Rutherford classification, and the ankle-brachial index (ABI) were assessed. Intra-arterial digital subtraction angiography including measurement of the mean pressure gradient was performed at the time of stent placement and at 6 months follow-up or in case of recurrence of symptoms. The Wilcoxon signed rank test and Kaplan-Meier method were applied for statistical analysis., Results: The immediate technical success rate was 94%. The clinical success rate immediately after the procedure was 96% and 85% at 6 months follow-up. Stent placement significantly decreased the severity of stenoses as well as the mean pressure gradients and significantly increased the ABI. Handling of the stent was judged good. No misplacement occurred. Foreshortening during deployment was negligible and no stent migration was seen. However, visibility of the stent during fluoroscopy was ranked as moderate to bad. Follow-up at 6 months revealed the cumulative angiographic primary patency rate (<50% restenosis and <10 mm Hg mean pressure gradient) to be 0.96., Conclusion: The evaluated self-expandable nitinol stent is an effective tool in treating iliac artery stenoses. Apart from poor visibility, handling was good. The angiographic patency rate is comparable with data reported in other stent trials.

Purpose: To evaluate the handling, the procedural success rate and the six-month outcome of a new Carbofilm coated balloon-expandable stent in iliac artery lesions., Materials and Methods: In a prospective study, 46 stenoses and 2 occlusions of the iliac arteries were primarily stented in 30 patients with the Isthmus CarboStent (Sorin Biomedica Cardio S.p. A., Saluggia, Italy). The ankle-brachial index (ABI) at rest was determined before intervention and at the six-month follow-up visit. Iliac angiography, including intraarterial pressure measurement, was performed before intervention, post-procedurally and at the follow-up visit., Results: All lesions were treated with procedural success. The mean degree of all stenoses was 73.9 % +/- 14.6 before and 2.4 % +/- 8.2 after intervention. The mean pressure gradient was 15.6 mm Hg +/- 10.1 before and 2.5 mm Hg +/- 2.7 after treatment. No or only a mild restenosis developed in 27 patients. The mean ABI increased from 0.64 +/- 0.21 to 0.86 +/- 0.33 and the mean pressure gradient was 2.7 mm Hg +/- 5.4 at the six-month visit. The six-month patency rate was 97.9 %. Three patients showed acute stent thrombosis due to an insufficient postprocedural antiplatelet regimen., Discussion: The Isthmus CarboStent is a safe and easy to handle balloon-expandable stent for interventional therapy of iliac artery lesions. The six-month patency rate is good. Despite its Carbofilm coating, postprocedural antiplatelet therapy is necessary.

Purpose: To evaluate artifacts of unexpended stents and to determine their exact position for MR-guided percutaneous transluminal angioplasty using real-time sequences., Materials and Methods: By using an in vitro model, 11 unexpended stents - 9 nitinol, 1 stainless steel, and 1 cobalt alloy - were investigated by MR. Each stent was studied in a vessel-phantom filled with saline solution. Imaging was performed using five different real-time sequences: fast low angle shot (Flash 2D), fast imaging with steady precession (true FISP, FISP, interactive true FISP) and segmented echo planar imaging (seg. EPI). Artifacts of the introducer system and the stent were calculated by four blinded radiologists (scale: 1 - artifacts, making an excellent contribution to visualization; 2 - artifacts, making mainly a contribution to visualization; 3 - artifacts, making no contribution to visualization). Furthermore, an evaluation of the visibility of the tip of the stent-catheter and the proximal and distal end of the stent was performed using a four-point scale (very good visibility to invisible)., Results: The artifacts of the introducer system and stent were rated best for Omnilink (1.3 +/- 0.47), Wallstent (1.6 +/- 0.5), Jostent (1.65 +/- 0.5) and Luminexx (1.65 +/- 0.5). The differences between Omnilink and Jostent as well as Omnilink and Luminexx were significant. A very good to good visibility of the catheter tip was observed with a mean of 1.7 +/- 0.66 for Omnilink followed by the Jostent (1.95 +/- 0.69), by the Wallstent(R) (2.1 +/- 0.72) and by Luminexx (2.5 +/- 1.14). Differences between Omnilink and Luminexx were significant. The visibility of the proximal and distal end of the stent was evaluated as very good to good in 4 stent catheters (Omnilink, Wallstent, Jostent, Luminexx). However, the differences between Omnilink and Jostent as well as between Omnilink and Luminexx, and between Wallstent and Luminexx were significant. For all evaluation criteria, the segmented EPI and the interactive true FISP were rated to be most suitable for visualization. There were no significant differences in the evaluation of these two sequences., Conclusion: Omnilink stent, Jostent, Wallstent, and Luminexx stent are suitable for MR-angioplasty due to their good visibility in MR. Segmented EPI- and a newly developed interactive true FISP-sequence enable an effective visualization of these stent-catheters.

The aim of this study was evaluation of a closure device (Perclose, Menlo Park, Calif.) for closure of the femoral artery access site in patients undergoing aggressive anticoagulation and platelet blockade after carotid stenting. Fifty-five patients who received clopidogrel in addition to aspirin and heparin as medication for carotid stenting were included for suture of the femoral access site after using 7- or 8-F guide catheters. The technical success, the time for suture, the clotting parameters, and complications were examined. Follow-up investigations, including ultrasound and clinical examinations, were performed. The groin was checked for possible hematoma, pseudoaneurysm, arteriovenous fistula, and local infection. Technical success was obtained in 51 of 54 patients (94%) after a mean procedure time of 6 min (range 5-10 min). The suture device was not used in one patient (2%) for anatomical reasons and failed to obtain hemostasis in 3 of 54 (6%) patients. In 4 of 54 patients (7%) bleeding was observed at the punctured site 4-6 h after intervention which was treated by a compression bandage. The mean dedicated activated clotting time was 137 s (range 29-287 s) before intervention and 349 s (150-958 s) just before deploying the Perclose device. During follow-up after 2 days (range 2-6 days) and 6 months no further complications of the puncture site were observed except for two large groin hematomas. No major complications occurred. Closure of the femoral access site after carotid stenting using a Perclose closure device is safe and effective even in patients receiving an aggressive anticoagulation and antiplatelet therapy.

Objective: To evaluate the treatment of malignant biliary stenoses and occlusions using a new stent., Methods: In a prospective study, 25 patients with malignant obstructive jaundice were treated with SMART(R) stents. The handling and the quality of stent expansion were documented. Stent function was assessed 2 - 4 days after intervention by cholangiography and laboratory tests. A follow-up was performed three months, after stent placement., Results: All lesions were treated successfully, with a total of 35 stents implanted. In 14 patients a further balloon dilatation was performed after stent placement (8 - 10 mm diameter/ 40 - 80 mm length). The mean serum bilirubin level decreased significantly from 11.6 mg/dl to 4.6 mg/dl after intervention (p < 0.05). The follow-up showed a mean serum bilirubin level at 4.0 mg/dl. In 4 cases (16 %) a further intervention (PTCD or stent) was performed. Six patients died due to tumor progression. The stents proved to be patent in 79 % (n = 15) of patients alive at the time of follow-up., Conclusions: Placement of the SMART stent for the therapy of malignant biliary lesions yields good technical and clinical results.

Rationale and Objectives: To evaluate the appearance of the vessel lumen after implantation of different vascular stents with the use of a computed tomographic (CT) angiography model., Methods: A vascular phantom was studied with helical CT and different slice thicknesses (2 and 3 mm) and pitch values (1.0, 1.5, and 2.0). Original transverse CT images and coronal reformations were evaluated. Fourteen different stents were analyzed with regard to changes in the stent lumen (attenuation values, noise, and artificial lumen narrowing)., Results: Some stents caused artifacts resulting in potential errors during evaluation of their patency. Assessment of the lumen was impaired in two stents (Strecker tantalum and Passager). Increased attenuation values were measured in all stents (increase of 8%-145%). The degree of artificial lumen narrowing was 4.4% to 77.8%., Conclusions: In most stents, reliable evaluation of the stent lumen seems possible. However, knowledge of the artifacts caused by different stent types is useful for the assessment of stent patency with CT angiography.

Purpose: Evaluation of the handling, technical success rate, and six-months patency rate of a new, premounted balloon-expandable stent in ostial renal artery stenoses., Material and Methods: In a prospective study, 27 ostial renal artery stenoses in 20 patients were primarily treated with the new "Renal Bridge Stent" (Medtronic AVE, Düsseldorf). All patients had a history of hypertension and 8 patients had renal dysfunction. The handling and visibility of the stent was scored on a three grade scale by the operators. Follow-up angiography including intra-arterial trans-stenotic pressure measurements was performed in 23 out of 27 stenoses (17 patients)., Results: Handling and visibility were scored as good by all operators. 26 of 27 stenoses were treated with technical success by implantation of 28 stents. The mean degree of stenosis was reduced from 74.2% to less than 5%. At 6 months, 8 stents out of 23 (35%) showed a significant in-stent stenosis (stenosis degree > 50% and intra-arterial pressure gradient > 10 mmHg). The stenosis rates were 63% using 5-mm stents, 30% using 6-mm stents, and 0% using 7-mm stents., Conclusion: Endovascular treatment of ostial renal artery stenosis with the used stent is safe and effective. The new stent shows a good handling and visibility. The high rate of in-stent stenoses might be explained by the rigid follow-up protocol including angiography, trans-stenotic pressure measurements, and the high number of 5-mm vessels in our study.

Purpose: To evaluate the transfemoral placement of a new, flexible stent-graft into the thoracic aorta and the suture-mediated closure of the femoral access., Patients and Methods: Five patients were treated endovascularly with a stent-graft for an aneurysm (n = 3) or acute dissection (n = 2) of the thoracic aorta via a femoral 24 F sheath. The femoral access site was closed with two suture-mediated closure devices after placement of the stent-graft., Results: The aneurysm or the false lumen was excluded from perfusion by the placement of the stent-graft in all patients. Hemostasis at the femoral access site was successful in all patients with the percutaneous suture device. A minor stenosis of the femoral artery was found angiographically in four patients after suture-mediated closure. Besides a reversible renal failure due to the medically induced hypotension for the treatment of an acutely ruptured aneurysm, no complications resulted from the stent-graft placement or the percutaneous suture., Conclusion: The percutaneous transfemoral placement of stent-grafts in the thoracic aorta using a suture-mediated closure of the access site is technically feasible. Long-term results of the technique have to be awaited.

Purpose: To assess the feasibility of magnetic resonance (MR) imaging-guided stent placement in iliac arterial stenoses., Materials and Methods: Thirteen patients with 14 iliac arterial stenoses were examined prospectively. Angioplasty was performed through a femoral sheath by using a conventional 1.5-T MR imaging system. Stents and catheters were visualized on the basis of their artifacts. Nitinol stents were placed with gradient-echo MR imaging guidance. Angioplasty balloons were inflated with gadolinium-based contrast material. Results were evaluated clinically and with both digital subtraction angiography (DSA) and contrast material-enhanced MR angiography., Results: Ten of 13 patients were treated with technical success by using MR imaging-guided intervention alone. Three patients were treated with additional fluoroscopic guidance, because complications (ie, panic attack, subintimal recanalization, and stent misplacement) occurred with MR guidance. The quality of the postinterventional contrast-enhanced MR angiograms of three of 12 lesions with stents was limited owing to stent-induced signal loss of the lumen. The mean stenosis degree after stent placement was significantly higher at contrast-enhanced MR angiography than at DSA (24.6% vs 6.2%). The mean MR imaging-guided procedure time was 74 minutes., Conclusion: MR imaging-guided stent placement in iliac arteries is feasible in select patients. The presented technique has limitations-that is, long procedure times, lack of real-time monitoring, and stent artifacts-that necessitate further modifications before it can be recommended for clinical use.

Purpose: Evaluation of the handling, technical success rate and six month patency rate of a new, premounted balloon-expandable stent in iliac artery lesions., Materials and Methods: In a prospective study 26 stenoses and 3 occlusions of the iliac arteries were primary treated in 24 patients (Fontaine IIa-III, mean age 60.4 year) with the "Flexible Iliac Bridge Stent" (Medtronic AVE, Düsseldorf). Five patients had bilateral stenoses. The ankle-brachial index (ABI) in rest and after exercise was determined before the intervention as well as 1-3 days, 1 and 6 months after the Intervention. The handling and visibility of the stent was scored on a three grade scale by the operators. Follow-up angiography including intraarterial pressure measurement was performed in 17 out of 24 patients (21 out of 29 lesions) after 6 months., Results: All 29 lesions were treated with technical success by implantation of 36 stents. The mean degree of the stenoses before intervention was 72.7 +/- 13.8% (+/- 1 standard deviation) and less than 5% in all cases postinterventionally. The mean pressure gradient before and after stent placement was 21 +/- 13.1 mm Hg and 0.8 +/- 2.3 mm Hg, respectively. The Fontaine stage improved by at least one in all patients. The mean ABI at rest improved from 0.63 +/- 0.15 to 0.89 +/- 0.16, and after exercise from 0.46 +/- 0.17 to 0.8 +/- 0.2, respectively. At 6 months 2 lesions out of 21 (9.5%) showed a restenosis of 55% and 70% with an intraarterial pressure gradient of 16 mm Hg and 27 mm Hg, respectively. After 6 months the mean ABI at rest decreased to 0.83 +/- 0.13, and to 0.72 +/- 0.14 after exercise. Handling and visibility was scored as good by all operators., Conclusion: Endoluminal therapy of iliac artery lesions with the used stent is safe and effective. The six month patency rate is comparable to the published data of other stents.

Purpose: To evaluate signal intensity changes influencing assessment of stent patency at contrast material-enhanced magnetic resonance (MR) angiography., Materials and Methods: By using an in vitro model, 14 stents-nine nitinol, one tantalum, two stainless steel, and two cobalt alloy-were investigated regarding their appearance at MR imaging. A vascular phantom consisting of tubes filled with 2.00 mmol/L gadopentetate dimeglumine in saline solution was studied in different orientations within the magnetic field. Imaging was performed with a fast three-dimensional gradient-echo sequence (4. 70/1.89 [repetition time msec/echo time msec]). Relative signal intensity reduction within the stents and the degree of artificial narrowing of the stent lumen were calculated., Results: The stent lumen was visible within 13 stents. A total signal void inside the stent lumen appeared in only one cobalt alloy stent. Artificial narrowing of the diameter was less than 33% in 10 of 14 stents. The tantalum stent and four nitinol stents seemed best suited for contrast-enhanced MR angiography. A bandlike artifact occurred at the ends of the stents when positioned along the readout direction., Conclusion: To differentiate between artifacts and stenoses, knowledge of the degree of signal intensity reduction and artificial lumen narrowing within vascular stents is essential. Stent geometry, relative orientation to the magnetic field, and alloy composition influence signal intensity alteration within the stent lumen.

Introduction: A prospective, randomized and controlled trial is conducted to compare carotid endarterectomy and carotid stenting in high grade symptomatic carotid artery stenoses., Methods: According to the study design symptomatic patients with a angiographically high-grade (> or = 70%) internal carotid artery stenosis are included. Pre- and postinterventional diagnostics during the hospitalization period includes neurological assessment, duplex sonography of the cervical and cerebral arteries and magnetic resonance imaging of the brain. Follow-up examinations are scheduled after 1, 6 and 12 months and consist of a neurological assessment and duplex sonography. After 12 months selective angiography and magnetic resonance imaging of the brain will be performed additionally. During a period of 9 months up to now 23/137 patients treated for a carotid artery stenosis were included in the study, 11 patients underwent surgery and 12 patients carotid stenting., Results: Carotid stenting and endarterectomy was primarily successful without residual stenosis > 30% in each patient without the occurrence of stroke or death. In 18 follow-up examinations (neurological assessment including duplex sonography) of 13 patients (13 follow-up examinations after 30 days, 5 after 6 months) no relevant restenosis and no stroke occurred., Conclusion: As of yet, carotid stenting was a safe procedure. Due to the small number of patients a definitive conclusion can not be drawn.

Rationale and Objectives: To evaluate MR imaging features of commercially available stents before, during, and after in vitro deployment as a step toward MR-guided stent deployment., Methods: Fourteen stents were deployed in a phantom under MR monitoring at 1.5 T by using a gradient-echo sequence. Device visibility was rated on a four-point scale (excellent, fair, poor, not visible)., Results: The Memotherm stent and the rolling membrane (RM) Wallstent showed excellent stent visibility and at least fair scores for artifact-induced narrowing of the stent lumen. Three stents (Palmaz, AVE, Easy Wallstent) showed excellent visibility of the stent but no visible lumen. Five stents (Strecker, Accuflex, Hemobahn, Passager, Sinus) displayed fair visibility. The delivery catheters of four stent systems (Smart, Vascucoil, Symphony, ZA) displayed severe black hole artifacts., Conclusions: The imaging features of several stent systems might be suitable for MR-guided intervention. The Memotherm and the Wallstent RM combine good visibility of the stent and the lumen.

Purpose: To investigate the feasibility of MR-guided stent angioplasty of iliac artery stenoses under passive visualization., Material and Methods: Three patients with short, concentric stenoses of the iliac arteries were enrolled. The vascular interventions were performed on a 1.5 T MR scanner (Magnetom Symphony, Siemens, Erlangen, Germany). Stents, guidewires, and balloon catheters were visualized on the basis of susceptibility artifacts. Contrast-enhanced MR angiography (ceMRA) was used to localized the stenosis prior to stent deployment. Nitinol stents were placed under MR-guidance using a fast 2D gradient echo technique. Balloon dilatiation was performed with an angioplasty catheter inflated with diluted gadolinium-DTPA. Postinterventional results were evaluated by ceMRA, DSA, and Doppler indices., Results: Position of the stent, stent deployment, and balloon dilatation were depicted by MR. All stents were correctly placed within the stenosis. Stent positions as monitored by MRI were identical to those seen on DSA images. All patients were treated successfully by the MR-guided intervention., Conclusion: An MR-guided stent angioplasty of simple iliac artery stenosis is feasible under passive visualization.

Stent placement is a widely used bail-out treatment for dissection of peripheral arteries. Below the level of the superficial femoral artery permanent stenting is complicated by a high incidence of subacute thrombosis and restenosis. We present two cases of arterial occlusion due to acute iatrogenic dissection of the popliteal and distal fibular arteries. Successful treatment was achieved with a new bail-out procedure. Strecker stents were implanted to seal off the dissection flap. Stents were retrieved easily after 24 hr using a myocardial biopsy forceps. After stent retrieval the temporarily stented segments were patent and showed a larger lumen compared with segments treated by balloon dilatation alone. Temporary stenting is a simple and safe procedure and offers the advantage of tacking up dissection membranes and preventing recoil. Persistent presence of a metallic implant as a source of continued injury and stimulus for intimal proliferation is avoided.

Purpose: To describe principles and results of percutaneous treatment of ischemic complications of aortic dissection., Materials and Methods: In five cases (four patients) aortic dissection was clinically complicated by renal (n = 4), iliofemoral (n = 2) or mesenterial ischemia (n = 1). After evaluation by means of computed tomography, angiography, and manometry, treatment consisted of balloon fenestration of the intimal flap, stent placement or both., Results: Eleven of 25 vascular beds were classified as ischemic. Treatment consisted of 11 balloon fenestration procedures in 3 patients, in one case supported by stent placement across the dissection membrane. Stents were placed in five renal arteries, one stent was placed in the true lumen of the aorta. One iliac artery was treated with balloon dilatation. One renal artery dissection became symptomatic after balloon fenestration and was treated successfully by stent placement. In all cases ischemia was resolved by endovascular treatment. All patients had persistent relief of symptoms. Mean follow-up time is 5.8 months., Conclusion: Ischemic complications of aortic dissection can be effectively and safely treated with stent placement and balloon fenestration.