Recanalization results after carotid stent placement

BACKGROUND AND PURPOSE: The details of stent reconstruction in the vascular lumen and of the adaptation of carotid stents, the vessel wall, and the vascular anatomy are only occasionally reported. The purpose of this study was to determine the immediate and longer-term anatomic results after implantation of self-expanding carotid stents. METHODS: In a retrospective study, pre- and postprocedural angiograms and duplex sonograms from 40 consecutive carotid stent procedures in 39 patients (22 men, 17 women; mean age, 67 years; age range, 53-84 years) with high-grade (> or =70 %) internal carotid artery (ICA) stenoses were evaluated to assess the expansion of the vascular lumen, apposition of the stent, and geometric changes in the ICA after the implantation of rolling-membrane and carotid Wallstents (n = 22) or Easy Wallstents (n = 18). RESULTS: Optimal widening of the lumen and apposition of the stent were achieved in 11 (28%) of 40 arteries. Residual stenoses (n = 16), free stent filaments not attached to the vessel wall (n = 21), and stent-induced kinking of the ICA (n = 6) were minor shortcomings of stent reconstruction. Because of one death, peri-interventional morbidity and mortality rates were 3%. During follow-up (median, 24 months), one high-grade restenosis, one ipsilateral stroke, and two ipsilateral transient ischemic attacks were observed. CONCLUSION: Suboptimal anatomic results frequently occur after endovascular treatment of atherosclerotic carotid artery stenosis with self-expanding Wallstents. With the exception of one symptomatic restenosis, no major complications or longer-term sequelae were clearly related to these findings, but further controlled follow-up studies of larger samples are required.     

Prospective analysis of cerebral infarction after carotid endarterectomy and carotid artery stent placement by using diffusion-weighted imaging

BACKGROUND AND PURPOSE: Small emboli arising from a friable plaque during carotid endarterectomy (CEA) and carotid artery stent placement (CAS) constitute a potentially important cause of periprocedural ischemic complications. To evaluate the frequency and significance of cerebral ischemic lesions of embolic origin after CEA and CAS, we examined patients with moderate to severe carotid stenosis by using diffusion-weighted (DW) imaging. METHODS: Twenty-four patients undergoing 26 CEAs and 20 patients undergoing 22 CAS were prospectively studied with pre- and post-treatment DW imaging of the brain within 7 days (mean, 2.3 days) before and within 7 days (mean, 3.2 days) after treatment. DW images were analyzed by two neuroradiologists blinded to the clinical results after CEA and CAS. Any new hyperintense lesion on DW image was interpreted as a post-treatment ischemic lesion. We compared post-treatment ischemic lesions with change in neurologic status, presence of plaque ulcerations, and severity of stenosis and compared the frequency of overall post-treatment complications between the two procedures. RESULTS: In 25 (96%) of 26 CEAs, post-operative brain DW images were unchanged. In one patient (4%), a new single asymptomatic hyperintensity was observed in the striatocapsule on the surgical side. In 14 (64%) of 22 CAS procedures, post-operative brain DW images were unchanged. In eight CAS cases (36%), new hyperintensities were seen on DW images. Among them, two were symptomatic with a major neurologic deficit lasting more than 7 days. Post-treatment brain or retinal major stroke rates were 4% (n = 1) for CEA and 14% (n = 3) for CAS. Overall symptomatic complication rates were 19.2% and 13.6%, respectively. CONCLUSION: Rate of ischemic brain lesions was significantly lower after CEA than after CAS, although most of these brain lesions were silent. Also, CEA is a safer procedure carrying a lower risk of post-operative cerebral ischemia. CAS, however, may be a comparable procedure considering the total complication rate and can be a more reliable procedure with advances in neuroprotective means.     

颈动脉复杂性狭窄的血管内支架治疗

目的　报道５ 例颈动脉复杂性狭窄的血管内支架治疗结果,旨在评价血管内支架治疗颈动脉复杂性狭窄的可行性及临床疗效。方法　５ 例具有症状性颈动脉狭窄患者行血管内支架置入术治疗。颈动脉狭窄的病因包括动脉粥样硬化（ｎ ＝ ３） 和放射治疗后纤维化狭窄（ｎ ＝ ２） 。Ｄｏｐｐｌｅｒ 超声波检查提示颈动脉狭窄,并经血管造影证实。本组病例使用自展式Ｗａｌｌｓｔｅｎｔ 型支架。术后随访４ ～２２ 个月。结果　颈动脉造影显示全部患者颈动脉狭窄程度均大于７５ ％ ;狭窄位于颈总动脉（ＣＣＡ）３ 例,颈内动脉（ＩＣＡ）２ 例;病变长度２０ ～６０ｍｍ 。全部患者颈动脉内支架置入成功。１ 例术中出现短暂性脑缺血（ＴＩＡ） ,无其它并发症发生。随访期间无神经病学后遗症和支架内血栓形成。Ｄｏｐｐｌｅｒ 超声波检查未发现血管内支架早期及迟发性再狭窄。结论　应用血管内支架治疗颈动脉复杂性狭窄具有技术可行性和安全性,具有满意的中期开通率。     

Hyperperfusion syndrome after external carotid artery stent placement in a case of bilateral internal carotid occlusion and external carotid stenosis

The authors describe a patient with bilateral internal carotid artery occlusion, bilateral external carotid artery (ECA) stenosis, and suboptimal collateral circulation from the right ECA to the right cerebral hemisphere. The patient manifested clinical and radiographic signs of hyperperfusion syndrome following stent placement in the right ECA. This represents a rare case of a stent placed in the ECA of a patient in addition to the development of hyperperfusion syndrome after the procedure.     

Postprocedural hypotension after carotid artery stent placement: predictors and short- and long-term clinical outcomes

PURPOSE: To describe the predictors of persistent hypotension after carotid artery stent (CAS) placement and define the clinical outcome of patients with this hemodynamic disturbance. MATERIALS AND METHODS: One hundred forty CAS procedures were performed in 133 consecutive patients. Post-CAS hypotension-defined as a greater than 40 mm Hg decrease in arterial pressure without evidence of hypovolemia, with a systolic pressure lower than 90 mm Hg at the end of CAS and lasting at least 1 hour-was observed in 25 patients (group 1); 108 patients did not have hypotension (group 2). RESULTS: Post-CAS hypotension developed in 33.9% of cases after balloon-expandable stent placement versus in 13.6% of cases after self-expanding stent placement (P =.04). In-hospital minor ipsilateral strokes occurred in 16% of cases in group 1 versus in 3% of cases in group 2 (P =.03). There was one (0.9%) major stroke (transient) and three (2.6%) transient ischemic attacks, all of which occurred in group 2 (not significant vs group 1 for both conditions). At 10 months +/- 4 (SD) of follow-up, there was greater total mortality in group 1 than in group 2 (20% vs 4%, P =.02), whereas neurologic events did not differ significantly between the groups. CONCLUSION: Hypotension due to carotid sinus stimulation is frequent after CAS with balloon-expandable stents. This phenomenon correlates with increased in-hospital complications and long-term risk of death.     

Emergency carotid artery stent placement in patients with acute ischemic stroke

BACKGROUND AND PURPOSE: An effective intervention has not yet been established for patients with acute ischemic stroke who present with serious neurologic symptoms due to occlusion or a high-grade stenosis of the internal carotid artery (ICA). The aim of our retrospective study was to investigate the feasibility, safety, and efficacy of emergency carotid artery stent placement to improve neurologic symptoms and clinical outcome. METHODS: Of 896 consecutive patients with acute ischemic stroke who were admitted to our institution within 7 days of onset from July 2000 to June 2003, 17 patients (1.9%) with occlusion or a high-grade stenosis of the ICA underwent emergency carotid artery stent placement. We reviewed their records for neurologic outcome, per the National Institutes of Health Stroke Scale (NIHSS) score, before and at 7 days after stent placement; clinical outcome, per the modified Rankin Scale score (mRS), at 90 days; frequency of procedure-related complications within 30 days; and recurrence rate of ipsilateral ischemic stroke within 90 days. RESULTS: Carotid lesions were dilated completely in all patients. Median NIHSS scores before emergency stent placement and at 7 days were 12 and 5, respectively, showing significant improvement (P < .01, Wilcoxon rank sum test). Ten patients (59%) had favorable outcomes (mRS score 0-1) at 90 days. Irreversible complications occurred in two patients (12%): distal embolism in one and intracerebral hemorrhage in the other. No ipsilateral ischemic stroke recurred. CONCLUSION: Emergency carotid artery stent placement can improve the 7-day neurologic outcome and may improve the 90-day clinical outcome in selected patients with ischemic stroke.     

Factors predictive of cerebral hyperperfusion after carotid angioplasty and stent placement

BACKGROUND AND PURPOSE: Cerebral hyperperfusion syndrome has been increasingly reported as a complication of carotid angioplasty and stent placement. The aim of the present study was to determine significant predictors of hyperperfusion phenomenon after carotid angioplasty and stent placement. METHODS: We retrospectively reviewed 30 consecutive patients with unilateral severe carotid stenosis who underwent angioplasty and stent placement. Resting cerebral blood flow (CBF) and cerebral vasoreactivity (CVR) to acetazolamide challenge were quantitatively measured to evaluate cerebral hemodynamic reserve. Split-dose [(123)I] iodoamphetamine single photon emission CT (SPECT) was performed before and 7 days after carotid angioplasty and stent placement. Technetium-99m hexamethylpropyleneamine oxime (HMPAO) SPECT was performed immediately after the procedure. RESULTS: Three patients had cerebral hyperperfusion phenomenon immediately after angioplasty and stent placement, as shown by HMPAO SPECT: One developed status epilepticus 2 weeks after the procedure. Significant predictors of hyperperfusion included patient age, pretreatment CVR, and pretreatment asymmetry index ([ipsilateral resting CBF/contralateral resting CBF] x 100). Variables determined not to be significant risk factors included pretreatment resting CBF value, degree of carotid stenosis, and interval from the onset of ischemic symptoms. CONCLUSION: Significant predictors of hyperperfusion phenomenon after carotid angioplasty and stent placement included patient age, pretreatment CVR, and pretreatment asymmetry index. Pretreatment CBF measurements, including those obtained by quantifying CVR and performing SPECT immediately after the procedure may aid in identifying patients at risk and in initiating careful monitoring and control of blood pressure to prevent hyperperfusion syndrome.     

Contralateral high-grade carotid artery stenosis or occlusion is not associated with increased risk for poor neurologic outcome after elective carotid stent placement

PURPOSE: To compare neurologic outcome after elective internal carotid artery (ICA) stents have been placed in patients with and in patients without contralateral ICA obstructions. MATERIALS AND METHODS: This study included 471 consecutive patients from a registry database who underwent elective ICA stent placement without cerebral protection for high-grade (greater than 70% stenosis of the ICA, according to the North American Symptomatic Carotid Endarterectomy Trial) symptomatic (n = 147) or asymptomatic (n = 324) ICA stenosis. Contralateral carotid arteries were investigated with angiography. Patients with and patients without contralateral high-grade stenosis (70%-99% stenosis, according to the North American Symptomatic Carotid Endarterectomy Trial) or occlusion were compared with respect to 30-day neurologic outcome by using the chi2 test and multivariate logistic regression analysis. RESULTS: Neurologic events were observed in 33 patients (7%) with 15 transient ischemic attacks, eight minor strokes, and 10 major strokes that led to death in two patients (combined stroke and death rate, 4%). Eighty-eight patients (19%) with contralateral high-grade ICA stenosis and 43 patients (9%) with contralateral ICA occlusion exhibited a similar rate of postintervention combined neurologic events (n = 9, 7%) compared with patients without contralateral high-grade ICA stenosis or occlusion (n = 24, 7%) (P =.94). No differences were observed between symptomatic and asymptomatic patients. Combined stroke and death rates were also comparable between symptomatic (four of 131, 3%) and asymptomatic (14 of 340, 4%) patients (P =.59). Of all variables tested, multivariate analysis did not detect any predictor for peri- or postinterventional neurologic events. CONCLUSION: Contralateral high-grade ICA stenosis or occlusion was not associated with an increased risk for neurologic events after elective ICA stent placement.     

New brain lesions at MR imaging after carotid angioplasty and stent placement

PURPOSE: To assess, with magnetic resonance (MR) imaging, the number and size of new brain lesions after carotid angioplasty and stent placement (CAS) and to evaluate the association of these new lesions with neurologic deficits and transcranial Doppler ultrasonographic (US) data. MATERIALS AND METHODS: Seventy-two consecutive CAS procedures were performed in 72 patients. Patients underwent neurologic examination before, during, immediately after, and 1 day, 3 months, and 1 year after CAS. MR imaging was used before and after CAS to assess the number of symptomatic and silent new infarctions. Two radiologists reviewed all pre- and postintervention MR images. The radiologists were blinded to the clinical data. RESULTS: Postprocedural MR images showed new lesions on the side of stent placement in 11 patients. In six patients, the new lesions were clinically silent. Two patients had a major stroke, one had a minor stroke, and two had transient ischemic attack. In patients who had had transient ischemic attack or stroke before CAS, the frequency of new lesions at postprocedural MR imaging was higher (23%) than in asymptomatic patients (12%); this difference was not statistically significant (P =.29). There was no statistically significant correlation between embolic load as detected with transcranial Doppler US monitoring and the occurrence of either clinical symptoms or new lesions seen at MR imaging. CONCLUSION: CAS is associated with embolic events. The majority of new lesions seen on postintervention MR images are not detected at neurologic examination.     

Angioscopic observation during carotid angioplasty with stent placement

This clinical report is the first to describe angioscopy during carotid angioplasty with stent placement. The average observation time was 3 minutes 43 seconds in 18 cases. The view was clear in 67% of cases. Lesions in the endothelium, rupture of the fibrous cap, clots, debris detaching from plaque, and stent struts were observed. No symptomatic ischemic complications occurred. Diffusion-weighted MR imaging after angioscopy showed asymptomatic ischemic lesions in 47% of cases.     

Horner syndrome related to ipsilateral carotid wall hematoma after stent placement for the treatment of carotid stenoses

BACKGROUND AND PURPOSE: We prospectively studied the incidence and natural history of Horner syndrome following stent-supported percutaneous angioplasty of the carotid artery (SPAC). We assessed the hypothesis that postinterventional Horner syndrome is related to ipsilateral carotid wall hematoma. METHODS: We performed duplex sonography of the carotid arteries and clinical examination in 28 consecutive patients before and 4 hours +/- 2, 24 hours +/- 2, and 7 days +/- 1 after SPAC. RESULTS: Within 24 hours +/- 2 after SPAC, 11 of the 28 patients developed ipsilateral Horner syndrome. Ten of these 11 patients had a postinterventional sonographic appearance of a carotid wall hematoma, whereas only two of the 17 patients without Horner syndrome had this finding (P <.001). In all patients, both Horner syndrome and carotid wall hematoma had resolved 7 days +/- 1 after SPAC. CONCLUSION: Horner syndrome appears to be a common yet transient event after SPAC. Although postinterventional Horner syndrome is significantly related to ipsilateral carotid wall hematoma, causality of the procedure-related formation of a carotid wall hematoma and oculosympathetic disturbance remains unproven.     

Assessment of coronary artery patency after stent placement using magnetic resonance angiography

The ability to noninvasively assess the patency of coronary stents would represent a significant advance. We evaluated the safety and ability of two-dimensional coronary MR angiography In imaging stents and suggesting patency. Coronary MR angiography of 26 coronary stents (Palmaz-Schatz) was performed in 16 patients 39 to 73 years of age. Studies were performed between 2 and 4 months after stent placement. All patients were symptom free at the time of imaging. Coronary MR angiography was performed with a commercial 1.5-T MR imager using an electrocardio-graphically gated pulse sequence with breath-holding. Images were obtained in mid-diastole with and without fat suppression. Image artifacts caused by the metal in the stents were clearly visualized in all 26 stents (100% sensitivity for stent detection). Arterial flow signal was seen in the coronary artery or graft distal to the stent in 25 of 26 cases (96%). All patients, except for the one in which distal flow could not be seen, remained symptom free for >2 years. The distribution of stent locations was as follows: 10 in the right coronary artery (RCA), 10 in the left anterior descending coronary artery (LAD), 2 in the left circumflex coronary artery, and 4 in saphenous vein grafts (SVGs) to RCA. One patient had 2 RCA and 2 LAD stents, one had 3 RCA and 1 LAD stents, one had 3 SVG stents, and two had double RCA stents. Coronary MR angiography is safe for noninvasive imaging of coronary stents, and in the proper clinical setting, it can be used to help suggest patency.     

Restenosis after carotid stent placement in patients with previous neck irradiation or endarterectomy

PURPOSE: Placement of a carotid artery stent (CAS) is an appealing treatment option for patients who have undergone neck irradiation or endarterectomy. Early outcomes and restenosis rates in these patients were analyzed and compared with those in de novo lesions. MATERIALS AND METHODS: Single-center, retrospective review of 269 CAS procedures that used cerebral embolic protection and nitinol stents was conducted from May 2001 through July 2006. In this cohort, 66 procedures were performed in patients with a history of external-beam neck irradiation (n=26) or carotid endarterectomy (CEA; n=40), designated as the "hostile neck" group. Mean follow-up was 16 months. RESULTS: The 30-day event rate for the entire group included major ipsilateral stroke (1.1%), minor posterior stroke (1.1%), and myocardial death (0.4%); none occurred in the hostile neck group. The rate of restenosis or occlusion for all 269 arteries was 2.6%. There was no significant difference in restenosis or occlusion rates between de novo lesions (2.0%, four of 203) and the hostile neck group (4.5%, three of 66; P=.17). Repeat angioplasty with or without stent implantation was employed for all patients with restenosis and resulted in no periprocedural stroke, death, or subsequent restenosis. CONCLUSIONS: Periprocedural outcomes of CAS procedures are similar in de novo lesions as in patients with a history of neck irradiation or CEA. Importantly, restenosis requiring repeat intervention remains uncommon, and its incidence is comparable between groups.     

颈动脉支架术后CT灌注成像研究

目的 探讨CT灌注成像(CTP)评估颈动脉支架(CAS)术后1周与1年的预后关系.方法 选择单侧颈动脉狭窄程度≥60%,对侧颈动脉无明显狭窄的20例CAS术患者.患者术前1周内、术后1周及术后1年均行头颅CTP检查,计算得到患侧与对侧的各参数比值,包括相对血容量(rCBV)、相对血流量(rCBF)及相对平均通过时间(rMTT).术前1周内均行头颅MRI及CT平扫,且术后即刻行头颅CT平扫,术后1年均行头颈部血管造影.将20例患者3个时间点大脑前动脉区(ACA区)、大脑中动脉区(MCA区)、大脑后动脉区(PCA区)、基底节区、前后皮质分水岭区(cortical watershed,CWS)及髓质分水岭区(internal watershed,IWS)的rCBV、rCBF及rMTT参数值进行重复测量的方差分析.结果 术前1周内、术后1周及术后1年3个时间点各区的rCBV差界无统计学意义(P值均＞0.05),PCA区的rCBF、rMTT差异也无统计学意义(P值均＞0.05),余各区的rCBF、rMTT差异均有统计学意义(P值均＜0.01).20例CAS患者术前1周内、术后1周及术后1年rCBF:ACA区0.86±0.06、0.95±0.04、0.98±0.07,MCA区0.81±0.04、1.06±0.04、1.03±0.07,基底节0.84±0.06、0.97±0.04、0.96±0.04,前CWS区0.78±0.03、0.97±0.03、0.96±0.02,后CWS区0.77±0.03、1.00±0.02.0.98±0.03,IWS区0.80±0.04、0.94±0.03、0.93±0.04(F值分别为18.95、146.41、63.03、540.85、415.97、164.19,P值均＜0.01).rMTT:ACA区1.17±0.05、1.04±0.04、1.01±0.06,MCA区1.41±0.06、1.08±0.04、1. 07±0.04,基底节1.20±0.06、1.06±0.04、1.05±0.04,前CWS区1.41±0.05、1.10±0.05、1.09±0.04,后CWS区1.43±0.10、1.07±0.06、1.08±0.06,IWS区1.29±0.10、1.09±0.05、1.11±0.07(F值分别为51.74、248.89、70.08、381.68、288.94、41. 53,P值均＜0.01).两两比较显示,术后1周、1年与术前1周相比差异有统计学意义(P值均＜0.01),而术后1周与1年rCBF、rMTT差界无统计学意义(P值均＞0.05).结论 对于单侧颈动脉狭窄的患者,CAS术具有较好的长期预后.术后1周与术后1年的灌注情况相仿.CAS术后1周CTP复查对预测长期灌注变化具有重要意义.     

Renal artery stenosis: duplex US after angioplasty and stent placement.

PURPOSE: To evaluate the hemodynamic outcome of technically successful percutaneous transluminal renal artery angioplasty and stent placement (PTRAS) with duplex ultrasonography (US). MATERIALS AND METHODS: Eighteen patients who underwent PTRAS in 22 renal arteries were prospectively examined. All had abnormal preprocedural duplex US findings. Those who had significant renal artery stenosis (>70%) at angiography and underwent technically successful percutaneous interventions were enrolled. Standard intrarenal duplex US parameters (acceleration index [AI], acceleration time, waveform morphology grade, and resistive index) were compared before and after interventions. RESULTS: A significant AI increase occurred after PTRAS (9.02 m/sec(2) +/- 4.85 [SD]), as compared with before intervention (2.34 m/sec(2) +/- 2.03; P <.001). Acceleration time significantly decreased from 0.084 second +/- 0.049 to 0.032 second +/- 0.008 (P <.01). There was also a significant resistive index increase from 0.69 +/- 0.12 to 0.79 +/- 0.12 (P <.01). Abnormal waveform morphology (modified Halpern waveform grade 3-6) was present in 19 (86%) of 22 intrarenal arteries prior to intervention, as compared with one (5%) after PTRAS (P <.001). In the instance in which an abnormal waveform persisted after intervention, waveform morphology improved from grade 6 to grade 3, with a concomitant AI increase from 0.96 to 5.1 m/sec(2). CONCLUSION: The findings suggest an important potential role for duplex US in noninvasive assessment of the immediate hemodynamic outcome and long-term follow-up of PTRAS.