Metallic stent placement for treating peripheral outflow lesions in native arteriovenous fistula hemodialysis patients after insufficient balloon dilatation

OBJECTIVE: The purpose of this study was to report our experience with metallic stent placement in the peripheral outflow veins in native arteriovenous fistula (A-V fistula) hemodialysis patients after insufficient balloon dilatation. MATERIALS AND METHODS: During the past 4 years, 12 A-V fistula dialysis patients in our hospital underwent metallic stent placement in the peripheral outflow veins to restore vascular access. The indications for metallic stent placement in our study included (1) recoil stenosis of outflow vein in six patients; (2) outflow venous rupture in two patients and dissection in one patient; and (3) large residual adherent thrombus in outflow aneurysms in three patients with thrombosed (arteriovenous) access. Self-expandable Wallstent or Jostent (Jomed, Abbott Laboratories) of appropriate size (6-10 mm in diameter) was chosen for use in these patients. Kaplan-Meier survival analysis was used to calculate the access patency rates. RESULTS: Twelve patients received stents. Eleven patients (92%) underwent successful dialysis after the procedure. One patient experienced complications due to incorrect positioning of the stent at the anastomotic site, causing flow compromise. The primary patency (+/- standard error) of the vascular access at 3, 6, 12, and 24 months was 92% +/- 8%, 81% +/- 12%, 31% +/- 17%, and 31% +/- 17%, respectively. The secondary patency of the vascular access at 3 months was 92% +/- 8%, and 82% +/- 12% at 6, 12, and 24 months each. CONCLUSION: Metallic stent placement is safe and effective in treating peripheral venous lesions in native A-V fistula hemodialysis patients after unsatisfactory balloon dilatation.     

Endovascular treatment for recurrent carotid stenosis]

PURPOSE: Surgery of recurrent carotid stenosis (RCS) has higher complication rates than primary carotid endoarterectomy (CEA). Percutaneous transluminal angioplasty (PTA) and stent placement were evaluated retrospectively with a view to proposing then as alternative procedures for RCS. METHODS: In the last 10 years, 19 patients underwent 20 endovascular procedures for RCS at our Department. The mean interval between CEA and PTA was 21 months (range 4-96): 14 patients had PTA within 2 years, 3 patients within 2 and 3 years,and 2 after 3 years. The mean degree of stenosis was 92% (range 80-95%). PTA was performed by balloon catheters (size 4-7 mm) without using cerebral protection device; one self-expanding stent was used to treat RCS after PTA. All patients underwent physical examination and carotid color-coded Doppler sonography in autumn 1999 RESULTS: The procedure was technically successful, with residual stenosis lower than 50%, in 17 of 19 patients; 10 patients showed residual stenosis lower than 30%. Carotid PTA was stopped due to transient neurological deficit in one case. One RCS proved uncompliant even though high-pressure balloon catheters were used. The mean follow-up period in 16 patients was 37.4 months (range 3-99 months). Carotid restenosis after PTA developed in 3 patients, respectively after 29,18 and 7 months. In the last case RCS was successfully treated by stent placement (Wallstent). The primary patency rate was 81%, the secondary patency rate was 88% and the late clinical success rate was of 94%. CONCLUSIONS: In selected cases, PTA without the use of cerebral protection devices and stent placement proved to be a safe and effective alternative treatment for early RCS. When an atherosclerotic lesion is suspected surgery or endovascular treatment with cerebral protection devices are recommended.     

大动脉炎颈动脉狭窄球囊扩张和内支架的治疗

目的：探讨应用球囊扩张和血管内支架治疗大支脉炎、颈动脉狭窄、材料和方法：３例大动脉炎性颈动脉狭窄的患者，狭窄段均超过８ｃｍ，１例单纯球囊扩张；２例球囊扩张后植入Ｗａｌｌｓｔｅｎｔ支架。结果：术后狭窄率均为０，达到了良好的治疗效果，单纯球囊扩张的动脉一年后动脉完全闭塞、西入血管内支架的２例，分别是在４．５个月和４个月检查，一例血管内支架的近端出现了再狭窄，另一例未出现再狭窄。结论：对于大动脉炎性长段     

Percutaneous transluminal cutting-balloon angioplasty for hemodialysis access stenoses resistant to conventional balloon angioplasty

Purpose: To examine the value of cutting-balloon percutaneous transluminal angioplasty (PTA) for hemodialysis access with residual stenosis after conventional balloon PTA.

Material and Methods: Angioplasty with conventional balloons was performed on 48 hemodialysis access stenoses in 28 patients. If the balloon waist still remained at the rated burst pressure, the balloon was reinflated up to three times. Fifteen of 48 stenoses had residual stenoses of more than 30% after conventional balloon PTA. In these 15 stenoses, additional cutting-balloon PTA was performed.

Results: The mean residual percent diameter stenoses before and after conventional balloon PTA were 77.6±3.4% and 48.6±8.5%, respectively. Additional cutting-balloon PTA decreased the mean residual percent diameter to 27.9±10.0%, and the cutting balloon was completely inflated without complication. In 12 patients, the 6-month primary patency rate (±SE) was 90.0% (9.5), and the 1-year primary patency rate (±SE) was 25.0% (14.8).

Conclusion: Additional cutting-balloon PTA was found useful for reducing residual stenosis.     

不同类型Budd-Chiari综合征的介入治疗(附200例分析)

目的探讨不同类型Ｂｕｄｄ－Ｃｈｉａｒｉ综合征（ＢＣＳ）介入治疗方法，评价经皮穿刺球囊扩张术（ＰＴＡ）和内支架（ｓｔｅｎｔ）治疗Ｂｕｄｄ－Ｃｈｉａｒｉ综合征的价值。材料与方法８年中诊治Ｂｕｄｄ－Ｃｈｉａｒｉ综合征患者２００例。介入治疗方法包括：下腔静脉球囊扩张术，下腔静脉球囊扩张和血管内支架放置术，经颈静脉行肝静脉成形术，经皮经肝和经颈静脉行肝静脉成形术，副肝静脉成形术，下腔静脉和肝静脉双球囊扩张术，下腔静脉和肝静脉双支架放置术。结果介入治疗ＢＣＳ的成功率为９４．４％。术中死亡率０．５％。严重的并发症为误穿心包导致心包填塞和血管内支架脱入右心房。结论ＰＴＡ和ｓｔｅｎｔ放置是一种安全、可靠的方法，可以替代外科对ＢＣＳ的治疗。     

Quantification of elastic recoil after balloon angioplasty in the iliac arteries.

PURPOSE: Elastic recoil of the arterial wall has been shown to be responsible for a significant loss of luminal area after balloon angioplasty in the coronary arteries, but it has not been well studied in the peripheral arteries. Because elastic recoil depends on the presence of elastin in the arterial wall, and the amount of elastin varies by artery and proximity to the aorta, the importance of this response to angioplasty may be different in peripheral arteries. The purpose of this study is to document the degree of elastic recoil in the iliac arteries, and analyze variables that might influence the results. MATERIALS AND METHODS: A series of 19 patients with 25 iliac artery stenoses underwent balloon angioplasty followed by placement of a Palmaz stent with the same-sized angioplasty balloon. The minimum luminal diameter of the lesion was measured before treatment, immediately after balloon angioplasty, and again after stent placement. The arterial diameter after stent placement was defined as the diameter of the inflated balloon. The degree of recoil was correlated with nine variables: patient age and sex, lesion location and length, lesion severity (as percent stenosis), the balloon:artery ratio, and three factors related to lesion morphology--complex versus simple, eccentric versus concentric, and calcified versus noncalcified. RESULTS: Elastic recoil averaged 36% +/- 11% and ranged from 19% to 54% in this series of patients. The only variable that significantly influenced the degree of elastic recoil was the balloon:artery ratio (P =.039), which was directly related. CONCLUSION: Elastic recoil is a significant limitation of balloon angioplasty in the iliac arteries. This study illustrates the importance of techniques that limit recoil, such as vascular stents, in angioplasty of the iliac arteries.     

Comparison of SMART stent placement for arteriovenous graft salvage versus successful graft PTA

PURPOSE: To compare the SMART (shape memory alloy recoverable technology) stent with percutaneous transluminal angioplasty (PTA) alone in hemodialysis access venous stenoses. MATERIALS AND METHODS: A prospective, nonrandomized study was undertaken in 60 patients with dysfunctional polytetrafluoroethylene dialysis grafts. Indications for stent placement were acute PTA failure, rapid restenosis, and vessel perforation. The primary endpoint was improved graft patency in patients treated with stents compared with that in patients whose disease responded to PTA alone. The secondary endpoints were lower postprocedural midgraft pressures and similar complication rates compared with PTA alone. RESULTS: The key venous stenosis was at the graft-to-vein anastomosis in all but two patients. Thirty-five patients showed a response to PTA alone. Sixteen patients received stents for stenoses greater than 30% after angioplasty, six for rapidly recurrent stenosis, and three for venous rupture. Nine patients received stents across the level of the elbow joint. Stenosis after intervention was significantly less frequent in the stent group (7% vs 16%; P = .001), but the midgraft systolic pressure ratios did not significantly differ. The clinical success rates were 100% after stent implantation and 97% after PTA alone. Except for venous rupture, there were no procedure-related complications, and, excluding early graft thrombosis, there were no complications at 30 days. A single stent fracture was found on follow-up. The mean primary graft patency times were 5.6 months after PTA and 8.2 months after stent treatment (P = .050). When stents were placed across the level of the elbow joint, the mean primary graft patency time was 8.9 months. CONCLUSION: Implantation of the SMART stent is safe and effective for the treatment of residual or rapidly recurrent dialysis access venous stenoses and is associated with better patency than PTA alone.     

Self-Expandable Stent Placement in Infrapopliteal Arteries After Unsuccessful Angioplasty Failure: One-Year Follow-up

The purpose of this prospective study was to evaluate whether stent placement in infrapopliteal arteries is helpful in failed percutaneous transluminal angioplasty (PTA). Infrapopliteal PTA was performed in 70 arteries of 66 patients with chronic critical lower limb ischemia. The group comprised 55 males and 11 females, with an average age of 63.4 (range, 42–82) years. Diabetes mellitus was present in 92.4% of patients. Only the palpable anterior tibial and posterior tibial arteries were evaluated. Stents (Xpert stent; Abbot Vascular, Redwood City, CA, USA) were placed in 16 arteries where PTA was not successful (the failure was defined as residual stenosis >30% after PTA). In 54 arteries simple PTA was performed and was technically successful. Twenty-four nondilated arteries with no significant stenosis served as a comparison group. The 12-month patency rate was evaluated according to a combination of palpation and Doppler ultrasound. In all cases stent placement restored the flow in the artery immediately after unsuccessful PTA. Twelve-month follow-up showed a patency rate of 82% in the PTA group, 78% in the stent group, and 69% in the comparison group. We conclude that stent placement in the case of unsuccessful infrapopliteal PTA changed technical failure to success and restored flow in the dilated artery. At 12-month follow-up the patency rate of infrapopliteal arteries stented for PTA failure did not differ significantly either from nonstented arteries with an optimal PTA result or from a comparison group of nonintervened arteries.     

Limb salvage procedure in occlusion of the infrapopliteal arteries

BACKGROUND/AIM: Limb salvage is a procedure for treatment of the causes of ischemia in the peripheral arteries of the lower limbs. This procedure consists of percutaneous transluminal angioplasty (PTA) of arteries of the infrapopliteal segment in the lower limbs, endovascular stents implantation and selective intraarterial thrombolytic therapy. The main PTA principle is balloon dilatation of a blood vessel and increasing blood flow in this zone. The aim of this study was to show the validity and benefits of applying this procedure in pathologically corrupted arteries of the infrapopliteal segment. METHODS: A prospective study included 30 patients: 15 with PTA dilatations, 13 with stents implantations and five with thrombolytic therapy. The follow-up pertiod was: immediately after the procedure, a month later, and six months later. RESULTS: Of the 15 patients with balloon dilatation, three still suffered from artery stenosis, and they additionally underwent stents implantation. These three patients were in the group of 13 patients who had underwent stent implantation. The last group consisted of five patients with thrombolytic therapy (urokinase, streptokinase, rt-PA--recombinant tissue plasminogen activator). Restenosis appeared only in the three patients from the first group (PTA) immediately after the intervention. A month later, there was no restenosis or ischemia of the limbs. After six months, restenosis appeared in three patients from the first group (PTA), in one patient from the second group (stent), and in two patients from the third group (thrombolytic therapy). The best results were shown by the stent implantation method (successful in 92.3% of the cases), PTA (75%), and thrombolytic therapy (60%). CONCLUSION: On the basis of the obtained results it can be concluded that the limb salvage method in case of occluded arteries of infrapopliteal segment is fully justified, especially the stent implantation method being successful in 92.3% of the patients within a six month-period of time, which is a relevant proof of its efficiency.     

Iliac artery stenosis or obstruction after unsuccessful balloon angioplasty: treatment with a self-expandable stent.

Obstruction or stenosis of the iliac artery was treated by placement of a self-expandable stent in 91 patients. A total of 100 lesions was treated. All patients had had poor results of balloon angioplasty including residual stenosis, iliac occlusion, and dissection. The stent used in all cases was a self-expandable stainless steel endoprosthesis mounted on a 7- or 9-French catheter and covered by an invaginated tubular rolling membrane. The diameter of the expanded stent varied from 7 to 12 mm. A total of 129 stents was placed. Technical success was 97%. Thromboses occurred immediately after placement in two patients and within the first month in six; these were mainly due to residual obstruction. Eighty-two (93%) of 88 patients with a follow-up longer than 3 months had no recurrent symptoms. Restenosis caused by intimal hyperplasia inside the stent occurred in 10 patients; these required repeated intervention in only four cases. In the remaining six patients, no further complications occurred. Our results show that self-expanding endoprostheses are of value for improving the results of inadequate percutaneous transluminal angioplasty.     

Treatment of intracranial atherosclerotic stenoses with balloon dilatation and self-expanding stent deployment (WingSpan)

The endovascular treatment of atherosclerotic intracranial arterial stenoses has previously been based on balloon dilatation or the deployment of a balloon expandable stent. Both methods have advantages (balloon: flexibility; balloon expandable stent: high radial force) and drawbacks (balloon: risk of elastic recoil and dissection; balloon expandable stent: limited flexibility, risk of injury to the vessel due to excessive straightening, overexpansion at ends of stent). A new combination of balloon dilatation, followed by the deployment of a self-expanding microstent has been applied in 15 patients with atherosclerotic arterial stenoses, symptomatic despite medical treatment. An anatomically and clinically adequate result was achieved in all patients. The initial degree of stenosis was 72% (mean). Balloon dilatation resulted in an average residual stenosis of 54% (mean), reduced further to a mean of 38% after stent deployment. Arterial dissection, occlusion of the target artery or symptomatic distal emboli was not encountered. In one patient, a side branch occlusion occurred after dilatation of a M1 stenosis, with complete neurological recovery. All patients were either stable or improved 4 weeks after the treatment. Recurrent TIA did not occur in any patient. Balloon dilatation and subsequent deployment of a self-expandable stent for the treatment of symptomatic intracranial arterial stenoses combines the advantages of both techniques and allows a rapid, clinically effective and technically safe treatment of these frequently challenging lesions.     

Carotid stenting without use of balloon angioplasty and distal protection devices: preliminary experience in 100 cases

BACKGROUND AND PURPOSE: A major concern during carotid artery stent placement is the potential for cerebral embolism. Diminishing the number of device manipulations across the lesion might reduce procedural stroke risk. For this purpose, we report our initial experience with carotid stent placement without the use of either balloon angioplasty or distal protection devices. MATERIALS AND METHODS: Eighty-seven consecutive patients with 100 carotid stenoses compose this series. Ninety four of the 100 hundred stented carotid arteries were either symptomatic (58 [58%]) or had a greater than 70% stenosis (36 [36%]). Six percent of them were asymptomatic and had stenosis between 50% and 70%. Patients underwent neurologic evaluation before the procedure and during follow-up at 1, 3, 6, and 12 months and annually thereafter. Carotid sonography and plain films of the neck were performed immediately after the procedure and then at the same time intervals. RESULTS: Primary stent placement was successful in 98 of 100 case subjects. In 2 case subjects, predilation was necessary before stent deployment. Neurologic periprocedural complications included 1 nondisabling and 1 disabling stroke and 5 transient ischemic attacks. The mean duration of follow-up was 23 months (range: 10-36 months). During the follow-up period, there were 5 deaths, all unrelated to the carotid disease, and no major stroke. The degree of stenosis decreased from a mean of 78.85% before the procedure to a mean of 21.23% immediately after. CONCLUSIONS: In this series, carotid stent placement without the use of either balloon angioplasty or distal protection devices was safe and effective with a low incidence of periprocedural complications.     

Percutaneous mechanical thrombectomy for thrombosed vessels with a hydrolyser (hydrodynamic thrombectomy catheter): clinical experience

A hydrodynamic thrombectomy catheter was prospectively evaluated for the treatment of thrombosed vessels. Seven patients (7 males: age range from 56 to 82 years; mean age: 79 years) presenting with acute or chronic occlusion of peripheral native arteries (n = 6) and dialysis shunt (n = 1) were treated with the hydrolyser (Cordis, Johnson and Johnson, Japan). Mean occlusion time was 135 days (range: 2-300 days), and mean thrombus length 16 cm (range: 5-20 cm). Removal of the thrombus was successful in five patients (71%), regardless of the length of the thrombus. Mean procedure time was 20 minutes (range: 15-30 minutes). No major complications occurred. Adjunctive thrombolysis was required for persistence of the residual thrombosed distal vessel in one patient. Adjunctive balloon angioplasty was performed in two patients (one native vessel and one dialysis shunt), and stent placement was performed in one patient (dialysis shunt). In two unsuccessful cases, the hydrolyser could not be advanced to the distal side because of the solid thrombus. Therefore, thrombolytic therapy was chosen. However, this therapy failed because the guidewire did not pass within the thrombus. Surgery was performed in these two patients. We conclude from this clinical experience that percutaneous thrombectomy with a hydrolyser is a promising technique for the treatment of thrombosed vessels. Especially in the acute stage of thrombosed occlusion, percutaneous thrombectomy with a hydrolyser is superior to thrombectomy with a Fogarty balloon catheter because of its shorter procedure time and fewer complications.     

Early thallium imaging after percutaneous transluminal coronary angioplasty: tomographic evaluation during adenosine-induced coronary hyperemia.

This study examined the immediate results of 201Tl imaging during adenosine-induced coronary hyperemia in 25 patients with one-vessel coronary artery disease, 4 +/- 3 days after percutaneous transluminal coronary angioplasty (PTCA). There were special features in our study: use of quantitative angiography and single-photon emission computed tomography (SPECT); a homogeneous group of patients (one-vessel disease) and a uniform stress (adenosine infusion). As a group, quantitative coronary angiography showed a decrease in percent diameter stenosis from 72% +/- 12% to 23% +/- 14%, p < 0.001. The thallium images were normal in 17 patients and abnormal in eight patients. However, of the eight patients, four had residual stenosis either in a secondary branch or downstream; one patient had local dissection (the residual stenosis could not be assessed reliably), two patients had > 50% residual diameter stenosis, and one patient had previous Q-wave myocardial infarction with a corresponding fixed thallium defect. In each of the eight patients with an abnormal image, a logical explanation could be identified. Thus, our results suggest that maximum reactive coronary hyperemia returns to normal immediately after PTCA, and that abnormal thallium results are due to inadequate dilatation or associated lesions.     

Diffusion-weighted imaging abnormalities after percutaneous transluminal angioplasty and stenting for intracranial atherosclerotic disease

BACKGROUND AND PURPOSE: The literature contains relatively few reports of distal embolism associated with intervention for intracranial atherosclerotic disease. Our purpose was to evaluate the frequency of thromboembolic events after percutaneous transluminal angioplasty (PTA) or stent placement in this setting by using diffusion-weighted (DW) imaging. METHODS: Between October 1999 and January 2004, 16 consecutive patients with symptomatic intracranial arterial stenosis greater than 60% were treated with PTA or stent placement without a protection system. Whole-brain DW imaging was performed before and after intervention. DW imaging findings were retrospectively analyzed and divided into three groups according to new hyperintensities: type A was none; type B, a single lesion; and type C, multiple lesions. RESULTS: Nine type A, five type B, and three type C lesions were detected after the interventions. All hyperintense lesions were less than 5 mm in diameter. All type C lesions occurred in the context of internal carotid artery stenosis treated with stent placement. DW imaging abnormalities occurred most frequently when PTA followed by stent placement was performed for long internal carotid artery stenoses. No new neurologic deficits occurred in any patient. CONCLUSION: In this series, PTA or stent placement or both for intracranial atherosclerotic lesions was safe. New DW imaging abnormalities were less frequent in patients who underwent PTA alone or primary stent placement than in those receiving PTA followed by stent placement.     

Subacute and chronic benign superior vena cava obstructions: endovascular treatment with self-expanding metallic stents.

OBJECTIVE: Our purpose is to report our clinical experience with patients who underwent endovascular treatment with Wallstents for subacute or chronic benign obstruction of the superior vena cava (SVC). SUBJECTS AND METHODS: Twelve patients who were an average of 54 +/- 12 years old were referred for treatment of severe SVC syndrome related to implanted central venous catheters (n = 8), postradiation fibrosis (n = 2), a permanent pacemaker (n = 1), or a benign tumor (n = 1). Symptoms were present for an average of 16 weeks (range, 4-48 weeks) before treatment. Diagnosis of SVC obstruction was confirmed with helical CT and pretherapeutic phlebography. Four patients had Stanford's type II stenosis; two, type III; and six, type IV. The mean clinical and radiologic follow-up intervals were 11 months (range, 1-36 months) and 7 months (range, 1 week to 32 months), respectively. RESULTS: Recanalization was successful in all patients. Fifteen stents were implanted in the 12 patients. Stents were placed after percutaneous balloon angioplasty in nine patients, and primary stent placement was attempted in three patients. We immediately achieved a satisfactory SVC diameter in all patients, whose symptoms were relieved completely within 1 week of stent placement. No technical or clinical complications occurred. SVC syndrome recurred in one patient 2 months after stent placement and was treated by placing a second stent. CONCLUSION: Endovascular treatment with stent placement should be considered relevant and safe for refractory benign SVC syndrome. However, a larger series and a longer follow-up period are needed to define the role of stent placement for this syndrome.     

血液透析患者中心静脉狭窄的介入治疗

目的探讨血液透析患者中心静脉狭窄介入治疗的方法及疗效。方法 2010年5月至2011年11月共收治20例发生中心静脉狭窄的血液透析患者,所有患者均具有中心静脉狭窄的临床症状、体征,并行MRA或CTA明确诊断,经静脉造影明确病变长度、范围和程度,行血管球囊扩张成形术(PTA)对病变部位进行治疗,成形术失败时,行血管支架植入术。术后随访患者的临床症状、MRA、超声等影像学检查。结果所有患者均成功行静脉造影,成功处理了20例患者共17条狭窄静脉,其中成功进行PTA 15例,支架植入成功2例,术后狭窄静脉血管通畅,侧支循环消失。首次PTA后再狭窄发生率为11.8%,再次行P1A。所有手术成功病例随访至今未出现再狭窄。结论血液透析患者中心静脉狭窄的介入治疗安全、有效,静脉通畅率良好。     

Cutting balloon angioplasty for primary treatment of hemodialysis fistula venous stenoses: preliminary results

PURPOSE: To assess the efficacy of the cutting balloon as the primary tool in percutaneous transluminal angioplasty of hemodialysis access stenoses. MATERIALS AND METHODS: A prospective study of symptomatic patients with stenoses of 50% or more in their hemodialysis accesses was undertaken. Provided that no contraindication to the use of cutting balloons existed, the stenoses were treated with the cutting balloon with use of a maximum of a 1:1.1 ratio between expected vessel diameter and balloon diameter. In cases in which dilation to the full diameter of the cutting balloon left a greater than 30% residual stenosis, postprocedural dilation with conventional balloons was carried out. Patient access function was followed. Twenty-nine patients with 42 stenoses have now reached 6 months of follow-up after cutting balloon angioplasty. RESULTS: Technical and clinical success rates were 100%. Slight local extravasation occurred in three cases: two had continued pain after the balloon was deflated and were therefore treated with balloon compression with resolution of symptoms and angiographic findings. In two cases, elastic recoil required stent placement to correct the stenosis. At 6 months, 22 patients (76%) remain in the primary patency category. Inclusion of those with primary assisted patency yields 26 patients (90%), and an additional patient had secondary patency, for a total of 93%. Two patients died of causes not directly related to dialysis. CONCLUSION: The high degree of technical and clinical success likely reflects the lack of major complications. The 6-month follow-up results match those of other series. Further follow-up will show whether this technique produces better results over the long term.     

Carotid artery stent placement with distal balloon protection: technical considerations

BACKGROUND AND PURPOSE: Most neurologic events that complicate the carotid artery stent placement procedure are embolic. Strategies are being developed and evaluated for their ability to minimize the clinical embolic risk. The purpose of this study was to determine the feasibility, safety, and technical considerations of performing carotid artery stent placement with use of a distal balloon antiembolization system. METHODS: Carotid artery stent placement with use of a commercially available distal balloon antiembolization system was performed in 303 patients (325 vessels). Clinical neurologic complications were adjudicated at the time of intervention and at 1 month. RESULTS: Technical success was achieved in all but one case, with reduction of the mean percentage carotid artery stenosis from 79 +/- 9% to 3 +/- 8%. Intolerance to internal carotid artery occlusion occurred in 11 patients (3.6%); in one patient the procedure was aborted, and in 10 the procedures were expeditiously completed with no adverse neurologic events. The 30-day combined rate of all occurrences of stroke and death was 2%. These events included three (0.9%) retinal emboli, three (0.9%) minor strokes, and one (0.3%) fatal stroke from brain hemorrhage, all of which occurred during the procedure with no events occurring after discharge. In addition, two (0.6%) transient ischemic attacks and three (0.9%) reperfusion syndromes occurred, with the patients experiencing complete recovery. CONCLUSION: Carotid artery stent placement with use of the distal balloon protection system is feasible and safe, and the short-term outcomes appear to be favorable. Optimal application of proper technique is important.     

Dilatation Mechanism of Balloon Angioplasty in Children: Assessment by Angiography and Intravascular Ultrasound

Purpose: Little information is available about the dilatation mechanism in children. This prospective study aimed to (1) evaluate the dilatation mechanism of balloon angioplasty in children with arterial stenosis, and (2) compare the morphological changes seen by intravascular ultrasound (IVUS) and angiography. Methods: Twenty consecutive patients, who had undergone a total of 23 procedures, were examined before and immediately after balloon angioplasty with a 4.3 Fr, 30 MHz rotational tip IVUS system. The lesions for IVUS study had resulted from coarctation of the aorta in six patients, pulmonary arterial stenosis in five, Blalock-Taussig shunt stenosis in three, subclavian artery stenosis in two, renal artery stenosis in two, coronary artery stenosis in one and ductus arteriosus in one. Results: Four distinctive morphological types were identified: type I with arterial stretching, type IIa with superficial tearing, type IIb with deep intimal-medial tearing, type III with flap formation, and type IV with dissection. The diameter of the narrowest site before and after balloon angioplasty increased significantly from 2.1 ± 1.4 mm to 4.6 ± 3.4 mm (p < 0.001). Eighteen of the 23 angioplasty procedures (78%) were considered to be successful, with a dilatation ratio of more than 50%. In most patients with successful dilatation, non-stretch mechanisms such as tearing, flap formation, or dissection were found. The positive percent (70%) of non-stretch mechanisms seen by IVUS was significantly higher than the positive findings (39%) by angiography (Χ²= 6.47, p < 0.02). Conclusions: Non-stretch morphology of the arterial wall may be a common mechanism of dilatation after balloon angioplasty in children with arterial stenosis. IVUS is a useful modality for evaluating the effectiveness of balloon angioplasty and the mechanism of dilatation in individual cases.