Prediction of cerebral hyperperfusion after carotid endarterectomy using cerebral blood volume measured by perfusion-weighted MR imaging compared with single-photon emission CT

BACKGROUND AND PURPOSE: Cerebral hyperperfusion syndrome is a rare but serious complication of carotid revascularization, including carotid endarterectomy (CEA) and carotid stent placement, which can occur in patients with preoperative impairments in cerebral hemodynamics. The purpose of this study was to determine whether preoperative cerebral blood volume (CBV) measured by perfusion-weighted MR imaging (PWI) could identify patients at risk for cerebral hyperperfusion after CEA. MATERIALS AND METHODS: CBV was measured by using PWI before CEA in 70 patients with unilateral internal carotid artery (ICA) stenosis (>or=70%) and without contralateral ICA steno-occlusive disease. Cerebral blood flow (CBF) was also measured by using single-photon emission CT before and immediately after CEA and on the 3rd postoperative day. RESULTS: A significant correlation was observed between preoperative CBV and increases in CBF immediately after CEA (r = 0.785, P < .0001). Whereas hyperperfusion immediately after CEA (CBF increase of >or=100% compared with preoperative values) was observed in 7 of 15 patients (47%) with elevated preoperative CBV, no patients with normal preoperative CBV exhibited post-CEA hyperperfusion. Furthermore, elevated preoperative CBV was the only significant independent predictor of post-CEA hyperperfusion. Finally, hyperperfusion syndrome developed on the 5th postoperative day in 2 of the 7 patients who displayed hyperperfusion immediately after CEA. CONCLUSION: Measurements of preoperative CBV by PWI might help to identify patients at risk for cerebral hyperperfusion after CEA in the absence of contralateral ICA steno-occlusive disease.     

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.     

Cerebral blood flow changes after endovascular treatment of cerebrovascular stenoses

BACKGROUND AND PURPOSE: Symptomatic cerebral hyperperfusion has an incidence of 5% after endovascular stent placement. We hypothesized that increases in cerebral blood flow (CBF) after endovascular stent placement are positively correlated with the severity of stenosis. METHODS: We studied patients with carotid (n=20) or vertebrobasilar (n=3) stenosis who were undergoing endovascular stent placement. Hemispheric CBF was measured by using intra-arterial xenon-133 technique (initial slope). RESULTS: CBF increased from 29 +/- 10 to 35 +/- 12 mL/100 g/min (P=.0003) at 39 +/- 12 minutes (range 13-60 minutes) after endovascular stent placement. Baseline characteristics or type of anesthesia did not affect the findings. Physiologic parameters remained constant between measurements: PaCO2 was 43 +/- 6 mmHg and arterial pressure was 89 +/- 16 mmHg. The degree of vascular stenosis (70% +/- 13%, range, 40-99%) was not correlated with change in CBF (r2=0.007, P=.70) or baseline CBF (r2=0.005, P=.31). CONCLUSION: CBF increased by 21% +/- 10% after treatment in the absence of clinical symptoms and without intracranial hemorrhage. Modest increases in CBF were common after endovascular revascularization. However, the increased CBF appeared to be unrelated to the degree of vascular stenosis, suggesting a relationship to availability of collateral flow pathways or a neurogenic influence.     

Diastolic blood pressure influences cerebrovascular reactivity measured by means of123I-iodoamphetamine brain single photon emission computed tomography in medically treated patients with occlusive carotid or middle cerebral artery disease

OBJECTIVE: Impaired cerebrovascular reactivity (CVR) to vasodilating agents is a predictor of the onset and prognosis of ischemic stroke. It is realized that the CVR improves or worsens when measured periodically during the clinical course in medically treated patients with occlusive cerebrovascular disease. In these patients, we investigated the possible relationship between the interval change in CVR and that in systemic blood pressure (BP). METHODS: Forty-two patients (14 females and 28 males, mean age +/- SD: 65.3 +/- 8.8 years) with severe stenosis or occlusion of the common carotid, internal carotid, or middle cerebral arteries repeatedly underwent single photon emission computed tomography (SPECT) studies using 123I-iodoamphetamine to measure cerebral blood flow (CBF) distribution and CVR at a more-than-6-month interval (mean +/- SD: 18.5 +/- 8.8 months). The CVR was separately estimated in cerebral hemispheres ipsilateral and contralateral to the most severe vascular lesion as the % increase in CBF after acetazolamide loading to CBF at rest. Systemic BP was measured four times at enrollment and the follow-up SPECT studies during resting and acetazolamide loading. Average BP at each SPECT study was an average of BP measurements during resting and acetazolamide loading. Interval changes in CVR were correlated with those in average systolic BP, average diastolic BP, and average mean arterial BP. RESULTS: The interval changes in CVR were significantly correlated with those in average diastolic BP in the ipsilateral hemisphere (y = 0.71x + 1.43, r2 = 0.11, p < 0.05) and in the contralateral hemisphere (y = 0.88x - 0.46, r2 = 0.16, p < 0.05) but not with those in average systolic BP or average mean arterial BP. CONCLUSIONS: In medically treated patients with steno-occlusive carotid artery or middle cerebral artery lesions, the interval change in CVR to acetazolamide by means of 123I-IMP SPECT was influenced by the diastolic BP at the SPECT studies. Monitoring diastolic BP is important to evaluate interval change in CVR.     

Cerebral hyperperfusion following carotid endarterectomy: diagnostic utility of intraoperative transcranial Doppler ultrasonography compared with single-photon emission computed tomography study

BACKGROUND AND PURPOSE: Cerebral hyperperfusion syndrome is a rare but serious complication of carotid endarterectomy (CEA). The aim of the present study was to determine whether intraoperative blood flow velocity (BFV) monitoring in the middle cerebral artery (MCA) by using transcranial Doppler ultrasonography (TCD) could be used as a reliable technique to detect cerebral hyperperfusion following CEA by comparing findings with those of brain single photon emission CT (SPECT). METHODS: Intraoperative BFV monitoring was attempted in 67 patients undergoing CEA for treatment of ipsilateral internal carotid artery (ICA) stenosis (> or =70%). Cerebral blood flow (CBF) was also assessed using SPECT, which was performed before and immediately after CEA. RESULTS: Intraoperative BFV monitoring was achieved in 60 patients. Of the 60 patients, post-CEA hyperperfusion (CBF increase > or =100%, compared with preoperative values) was observed in six patients. The sensitivity, specificity, and positive predictive value of the BFV increases immediately after declamping of the ICA for detecting post-CEA hyperperfusion was 100%, 94% and 67%, respectively, with a cut-off point 2.0-fold that of preclamping BFV. The sensitivity and specificity of the BFV increases at the end of the procedure for detecting post-CEA hyperperfusion were 100% for both parameters, with cut-off points of 2.0- to 2.2-fold BFV of preclamping value. Hyperperfusion syndrome developed in two patients with post-CEA hyperperfusion, but intracerebral hemorrhage did not occur. In one of these two patients, BFV monitoring was not possible because of failure to obtain an adequate bone window. CONCLUSION: Intraoperative MCA BFV monitoring by using TCD is a less reliable method to detect cerebral hyperperfusion following CEA than postoperative MCA BFV monitoring, provided adequate monitoring can be achieved.     

Intentional Stent Stenosis to Prevent Hyperperfusion Syndrome after Carotid Artery Stenting for Extremely High-Grade Stenosis

BACKGROUND AND PURPOSE:Intracranial hemorrhage due to hyperperfusion syndrome is a severe carotid artery stent placement complication of extremely high-grade stenosis, causing hemodynamic insufficiency. To prevent hyperperfusion syndrome, we attempted intentional residual stent stenosis and implemented “gentle” carotid artery stent placement, defined as carotid artery stent placement using a closed-cell stent coupled with slight balloon predilation, without balloon postdilation. Gradual stent expansion was expected. We investigated the incidence of hyperperfusion syndrome and long-term outcomes after gentle carotid artery stent placement.MATERIALS AND METHODS:We included patients who underwent carotid artery stent placement for extremely high-grade stenosis from January 2015 to March 2019. We defined extremely high-grade stenosis as carotid stenosis with conventional angiographic “slow flow” and a reduced MCA signal intensity on MRA. A reduced MCA signal intensity was defined as MCA with a relative signal intensity of <0.9 in the ipsilateral compared with the contralateral MCA. We evaluated the stent diameter, CBF on SPECT, hyperperfusion syndrome, and intracranial hemorrhage. We defined hyperperfusion syndrome as a triad of ipsilateral headache, seizure, and hemiparesis.RESULTS:Twenty-eight of the 191 patients met our inclusion criteria. After carotid artery stent placement, their median minimal stent diameter was 2.9 mm, which expanded to 3.9 mm at 4 months. Neither cerebral hyperperfusion syndrome nor intracranial hemorrhage occurred.CONCLUSIONS:The gentle carotid artery stent placement strategy for intentional residual stent stenosis may prevent hyperperfusion syndrome in high-risk patients. Stents spontaneously dilated in 4 months.

Hyperperfusion syndrome (HPS) is a critical complication of carotid revascularization.^1-4 HPS occurs after revascularization of extremely high-grade carotid artery stenosis (ex-HS) causing cerebral hemodynamic insufficiency.^1,5 SPECT was used in Japan to assess hemodynamic insufficiency before carotid artery stent placement (CAS) in 127 (82.5%) of 154 institutions;⁶ however, the risk of HPS was evaluated routinely by only 102 (15.5%) of 664 anesthesiologists in a US survey about carotid endarterectomy,⁷ and SPECT was not included in the survey. Thus, a simple index to identify high-risk patients is required. Classic angiographic “slow flow” in the MCA⁴ or reduced MCA signal intensity (SI) on MRA⁸ is a feasible index in most facilities. We, therefore, defined an ex-HS with a carotid artery stenosis rate of > 80% or a minimal luminal diameter (MLD) of <1 mm, coupled with angiographic slow flow and reduced SI in the ipsilateral MCA, as hemodynamic insufficiency (HI) criteria.The prevention of HPS has not been established,^9,10 though staged revascularization is a treatment option.^11,12 Therefore, we attempted to perform intentional residual stent stenosis to prevent marked hyperperfusion after CAS. To retain stent stenosis intentionally, we implemented “gentle” CAS, defined as CAS using a closed-cell stent coupled with slight balloon predilation, without poststenting balloon dilation. Compared with open-cell stents, the closed-cell stents may slowly self-expand and decrease embolic complications by avoiding dislodgement of the plaque while the stent expands, because the radial force in closed-cell stents is weaker than that in open-cell stents.¹³ Gradual and gentle self-expansion of the stent was the expected outcome.We investigated the incidences of hyperperfusion phenomenon (HPP), HPS, and intracranial hemorrhage (ICH) and the long-term clinical and angiographic outcomes after gentle CAS for ex-HS identified by the HI criteria.⁸ Furthermore, we evaluated the validity of the HI criteria.     

Intracranial hemorrhage after stenting and angioplasty of extracranial carotid stenosis

BACKGROUND AND PURPOSE: The transluminal angioplasty and stenting procedure has been recently advocated as a potential alternative to surgical endarterectomy for the treatment of severe extracranial carotid stenosis. This study assesses the incidence and significance of intracranial hemorrhage occurring after this procedure. METHODS: We retrospectively reviewed 104 carotid arteries (96 internal, two external, and six common) in 90 patients (63 male; mean age, 69.4 years; range, 48-88 years) who underwent primary stenting and angioplasty by use of Wallstents (103/104) at three centers between January 1996 and January 1999. Seventy-five (83%) patients were referred by neurosurgery departments. Seventy-one (68%) arteries were symptomatic; the mean stenosis percentage was 85% (range, 40-99%). RESULTS: Four intraparenchymal hemorrhages occurred, representing 4.4% of patients and 3.8% of vessels, after angioplasty and stent placement. The mean preoperative stenosis percentage was 95% (range, 90-99%). One hemorrhage occurred immediately after stent placement, whereas the three other hemorrhages occurred in a delayed fashion (mean, 2.8 days). The mean hematoma size was 4.8 cm (range, 2-8 cm). Three patients had associated subarachnoid or intraventricular bleeding; the fourth had associated subdural hemorrhage. Three hemorrhages were fatal; the fourth experienced two seizures only. No acute neurologic symptoms were present prior to hemorrhages, and there was no postprocedural hypertension in these patients. All had been receiving antiplatelet agents as well as intraprocedural IV heparin. CONCLUSION: Intracranial hemorrhage can occur after carotid angioplasty and stenting. We speculate that this represents cerebral hyperperfusion injury. The 3.8% incidence of cerebral hemorrhage observed is approximately sixfold greater than that reported post endarterectomy (0.6%) (95% CI, 0.2-8.7%). This is not statistically significant in this small study group. This trend may reflect patient selection, different anticoagulation protocols, and/or study population size. Additional data are needed to determine the safety and efficiency of carotid stenting as a treatment for carotid stenosis.     

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.     

Significance of postoperative crossed cerebellar hypoperfusion in patients with cerebral hyperperfusion following carotid endarterectomy: SPECT study

Purpose Cerebral hyperperfusion after carotid endarterectomy (CEA) results in cerebral hyperperfusion syndrome and cognitive impairment. The goal of the present study was to clarify the clinical significance of postoperative crossed cerebellar hypoperfusion (CCH) in patients with cerebral hyperperfusion after CEA by assessing brain perfusion with single-photon emission computed tomography (SPECT). Methods Brain perfusion was quantitatively measured using SPECT and the [¹²³I]N-isopropyl-p-iodoamphetamine-autoradiography method before and immediately after CEA and on the third postoperative day in 80 patients with ipsilateral internal carotid artery stenosis (≥70%). Postoperative CCH was determined by differences between asymmetry of perfusion in bilateral cerebellar hemispheres before and after CEA. Neuropsychological testing was also performed preoperatively and at the first postoperative month. Results Eleven patients developed cerebral hyperperfusion (cerebral blood flow increase of ≥100% compared with preoperative values) on SPECT imaging performed immediately after CEA. In seven of these patients, CCH was observed on the third postoperative day. All three patients with hyperperfusion syndrome exhibited cerebral hyperperfusion and CCH on the third postoperative day and developed postoperative cognitive impairment. Of the eight patients with asymptomatic hyperperfusion, four exhibited CCH despite resolution of cerebral hyperperfusion on the third postoperative day, and three of these patients experienced postoperative cognitive impairment. In contrast, four patients without postoperative CCH did not experience postoperative cognitive impairment. Conclusions The presence of postoperative CCH with concomitant cerebral hyperperfusion reflects the development of hyperperfusion syndrome. Further, the presence of postoperative CCH in patients with cerebral hyperperfusion following CEA suggests development of postoperative cognitive impairment, even when asymptomatic.     

Hyperperfusion syndrome with hemorrhage after angioplasty for middle cerebral artery stenosis

Hyperperfusion syndrome is a well-documented complication of carotid endarterectomy, as well as internal carotid artery angioplasty and stent placement. We report a similar complication after distal intracranial (middle cerebral artery [MCA] M2 segment) angioplasty. To our knowledge, this is the first report of hyperperfusion syndrome after intracranial angioplasty of a distal MCA branch.     

Carotid artery disease: evaluation with acetazolamide-enhanced Tc-99m HMPAO SPECT.

Sixty patients were studied for carotid artery disease and were further evaluated with hexamethyl-propyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) both at baseline (with the patient resting) and after administration of acetazolamide (ACZ). Of these 60 patients, 58 (97%) had symptoms and 49 (82%) had stenoses greater than 70% in at least one internal carotid vessel. Nine patients (15%) had symmetric findings on baseline examinations and at SPECT with ACZ. Thirty-two patients (53%) had asymmetric findings on baseline, but in 24 of these patients (75%) additional lesions were observed after ACZ administration. Nineteen patients (32%) had asymmetric findings only after ACZ was administered. HMPAO SPECT with ACZ allows detection of diminished cerebral perfusion reserve that is not found when HMPAO SPECT is performed with the patient at rest. This procedure helps provide an objective evaluation of the hemodynamic effects of carotid stenosis.     

Clinical significance of cerebrovascular reserve in acetazolamide challenge —comparison with acetazolamide challenge H2O-PET and Gas-PET—

OBJECTIVE: The response of cerebral blood flow (CBF) to acetazolamide (ACZ) challenge is frequently determined in clinical settings to evaluate cerebrovascular reserve (CVR). A reduced CVR can indicate patients with occlusive cerebrovascular disease and compromised hemodynamics who may be at increased risk of cerebral ischemia. However, how precisely ACZ reflects cerebral hemodynamic impairment remains obscure. The present study aims to clarify the pathological significance of CVR in patients with occluded carotid arteries. METHODS: We recruited seventeen patients with occlusive lesions in the internal carotid artery (ICA) or middle cerebral artery (MCA). We assessed these patients in terms of resting cerebral blood flow (CBF) and the CVR response to ACZ challenge using H20 positron emission tomography (PET). In addition, we evaluated hemodynamic parameters including oxygen extraction fraction (OEF) using Gas-PET. RESULTS: We identified a significant negative correlation between the CVR and OEF or the cerebral blood volume (CBV)/CBF ratio, as a potential index of cerebral perfusion pressure. Although the CVR values were reduced in all regions with elevated OEF (Stage II), these values were highly variable regardless of the CBV/CBF ratios. The cut-off value of CVR alone could not detect Stage II, but when combined with resting CBF, misery perfusion accompanied by increased OEF was detected with high sensitivity (6/7) and specificity (61/62). CONCLUSION: CVR could be applied as an index reflecting both autoregulatory capacity and OEF. The present study also supported the notion that SPECT with ACZ challenge can be clinically applied to detect misery perfusion.     

Short-term changes in cerebral microhemodynamics after carotid stenting

BACKGROUND AND PURPOSE: The cerebral hemodynamic sequelae of interventions in patients with severe internal carotid artery (ICA) stenoses are not fully understood. In this study, we sought to determine the immediate changes in cerebral perfusion characteristics, determined by MR imaging in patients who have undergone unilateral transluminal angioplasty and stent placement. METHODS: Eleven patients with symptomatic high-grade ICA stenosis underwent MR imaging within 4 hours before and within 3 hours after carotid stent placement. First-pass gadolinium-enhanced imaging of perfusion was performed by using a gradient-recalled echo-planar technique. Localized relative cerebral blood volume (rCBV) and bolus first-moment transit time (TT(FM)) were calculated for different vascular territories (middle, anterior, and posterior cerebral arteries) in each hemisphere. RESULTS: Significantly longer TT(FM) (P <.005) was observed in the symptomatic territory of the middle cerebral artery before intervention. After intervention, TT(FM) remained significantly longer in this territory (P <.05). However, the magnitude of the interhemispheric asymmetry had declined significantly (50-60% reduction; P <.05). No significant differences or changes in rCBV were identified between hemispheres, between images, or in areas of unilateral leptomeningeal enhancement after intervention. CONCLUSION: MR can demonstrate short-term partial resolution of timing asymmetry in interhemispheric perfusion after angioplasty and stent insertion for severe stenosis of the ICA.     

Stenotic Transverse Sinus Predisposes to Poststenting Hyperperfusion Syndrome as Evidenced by Quantitative Analysis of Peritherapeutic Cerebral Circulation Time

BACKGROUND AND PURPOSE:Hyperperfusion syndrome is a devastating complication of carotid stent placement. The shortening of cerebral circulation time after stent placement is seen as a good indicator of the development of hyperperfusion syndrome. The purpose of our study was to evaluate whether patients with ipsilateral transverse sinus stenosis are prone to having shortened cerebral circulation time after stent placement, subsequently leading to the possible development of hyperperfusion syndrome.MATERIALS AND METHODS:Forty-nine patients with >70% unilateral carotid stenosis undergoing stent placement were recruited for analysis. Group A consisted of patients with a stenotic ipsilateral transverse sinus >50% greater than the diameter of the contralateral transverse sinus; the remaining patients were in group B. Quantitative DSA was used to calculate cerebral circulation time. Cerebral circulation time was defined as the time difference between the relative time to maximal intensity of ROIs in the proximal internal carotid artery and the internal jugular vein. ΔCCT was defined as cerebral circulation time before stent placement minus cerebral circulation time after stent placement. ΔCCT, white matter hyperintensity signals, and sulcal effacement in MR imaging were compared between the 2 groups.RESULTS:ΔCCT was significantly shorter in group A (0.65 ± 1.3) than in group B (−0.12 ± 1.4). Three patients had white matter hyperintensity signals in group A, and 1 developed hyperperfusion syndrome. Group B showed no MR imaging signs of hyperperfusion syndrome.CONCLUSIONS:Ipsilateral hypoplastic transverse sinus was associated with prolonged cerebral circulation time before stent placement and greatly shortened cerebral circulation time after stent placement. Inadequate venous drainage might play a role in impaired cerebral autoregulation and might influence the development of poststenting hyperperfusion syndrome.

Carotid stent placement restores cerebral perfusion to the ischemic area to prevent further ischemic insults. The normalized cerebral circulation after stent placement also correlates with improved neurologic functional outcomes.^1–3 Although carotid stent placement has been proved a safe therapy for those with significant extracranial stenosis, complications do occur, including thromboembolic events and hyperperfusion syndrome.⁴ Hyperperfusion syndrome has a characteristic triad (headache, seizure, and focal neurologic deficits) and typically occurs within several hours or days after the procedure.^5–7 Risk factors for hyperperfusion have been proposed, including high-grade stenosis, poor collateral circulation, high blood pressure, age, and blood-brain barrier breakdown.^7–11Nevertheless, the underlying pathophysiology of HPS has not been well evaluated due to its low incidence (0.7%–3%).^7,9,12 The generally accepted explanation emphasizes a failure of autoregulation after sudden augmentation of cerebral blood inflow following carotid stent placement. To assess cerebral perfusion objectively and immediately within the angiography suite, we used quantitative color-coded DSA to evaluate the changes in cerebral circulation time before and after the procedures.^13,14 CCT is defined as the time required for blood to traverse through the brain, and it can serve as a surrogate for cerebral perfusion during angiography.¹⁵ Obtaining immediate cerebral hemodynamic measurements can help detect HPS early and facilitate immediate, aggressive postprocedural blood pressure control.Despite careful patient selection and postprocedural care, we have nonetheless encountered unexpected cases of HPS after carotid stent placement. A recent study has shown that shortened CCT after carotid stent placement carries higher risks for HPS.¹² After reviewing our cases, we found that those patients with HPS usually had ipsilateral hypoplastic or atretic transverse sinuses. The purpose of our study was to determine the impact of venous stenosis on CCT after stent placement and to determine whether venous stenosis is a risk factor for HPS.     

血管支架成形术治疗症状性大脑中动脉狭窄

目的研究血管内支架成形术治疗症状性大脑中动脉狭窄的疗效及安全性。方法对27例症状性大脑中动脉狭窄患者行血管腔内成形术。结果27例患者中,24例成功置入冠脉支架,术后即刻造影显示狭窄程度为(8±4)%,较术前(80±19)%改善明显。2例因支架置入困难改行经皮血管腔内成形术(PTA)。平均随访18个月。25例患者术后短暂性脑缺血发作均未发生。无责任血管区新发脑梗死。1例支架置入后3h发生再灌注性脑出血。1例支架脱落后于颈内动脉虹吸部,后用抓捕器取出。1例支架置入术后6个月发生再狭窄。结论经皮血管内支架成形术是治疗症状性大脑中动脉狭窄的一种较安全有效的方法。长期疗效有待于进一步观察。     

血管内支架治疗颈内动脉狭窄27例体会

目的总结血管内支架治疗颈内动脉狭窄的疗效及其体会。方法选择我院2004年12月至2006年3月经DSA证实颈内动脉狭窄患者27例，全部经全脑血管造影及颈部超声检查后，行经皮腔内血管成形和支架植入术治疗。结果术后超声及DSA证实，手术成功率100％，治疗后残余狭窄率均低于30％，27例患者中与操作相关的并发症包括2例（7．4％）出现可逆性小卒中；3例（11．1％）出现术中球囊扩张时对侧肢体局灶性癫痫发作；5例（18．5％）血管痉挛；6例（22．2％）出现低血压和心动过缓。18例随访6个月～18个月，无1例再次发生脑梗死。结论血管内支架成形术是一种治疗颈内动脉狭窄安全有效的方法，提高术者操作技巧及加强围手术期监护可以大大降低手术并发症和病死率。     

Carotid stent delivery in an XMR suite: immediate assessment of the physiologic impact of extracranial revascularization

BACKGROUND AND PURPOSE: Patients undergoing stent placement as treatment for severe stenosis of the internal carotid artery (ICA) were assessed with MR imaging in a combined MR-radiographic (XMR) angiography suite. MR imaging was performed before and immediately following conventional radiography-guided stent placement. Changes in MR imaging measurable properties, including flow and perfusion, resulting from stent placement were evaluated. PATIENTS AND TECHNIQUES: MR imaging analysis was performed for 12 patients with >70% stenosis of the ICA before and after conventional radiography-guided deployment of a carotid stent. MR imaging acquisitions included angiography, quantitative flow analysis, perfusion, diffusion, and turbo-fluid-attenuated inversion recovery (FLAIR). These acquisitions were all performed immediately before and following stent placement by using conventional techniques. RESULTS: MR angiography proved sufficient for identifying the target lesion and permitting targeted flow analysis. MR flow analysis demonstrated a marked increase in flow in the treated carotid artery (+2.2 +/- 1.2 mL/s) and little change in other extracranial arteries. MR perfusion imaging showed no significant differences in relative cerebral blood volume between hemispheres before or after treatment, but there was a modest decrease in mean transit time and time to peak evident in the treated hemisphere after stent placement. Diffusion imaging did not demonstrate any ischemic foci resulting from carotid stent treatment. Hyperintensity of the CSF was noted on turbo-FLAIR acquisitions in the ipsilateral hemisphere following stent placement in 75% of patients. CONCLUSION: MR imaging reliably reflects the state of the carotid artery and provides a means of monitoring and quantifying the effects of revascularization.     

Acetazolamide-challenged perfusion magnetic resonance imaging for assessment of cerebrovascular reserve capacity in patients with symptomatic middle cerebral artery stenosis: comparison with technetium-99m-hexamethylpropyleneamine oxime single-photon emission computed tomography

Objectives

Acetazolamide-challenged perfusion magnetic resonance imaging (MRI) has been shown as a method for assessment of cerebrovascular reserve (CVR) capacity in patients with atherosclerotic steno-occlusive disease of internal carotid artery. We have assessed the feasibility of the acetazolamide-challenged perfusion MRI for evaluating CVR in symptomatic patients with severe middle cerebral artery (MCA) stenosis (≥70%) by comparison with the acetazolamide-challenged technetium-99m-hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography (SPECT).

Methods

Seventeen prospectively enrolled patients with symptomatic unilateral MCA stenosis underwent technetium-99m-hexamethylpropyleneamine oxime SPECT and perfusion MRI without and with acetazolamide challenge, respectively. Acetazolamide-challenged SPECT and perfusion MRI were compared quantitatively by Region of interest (ROI) analysis.

Results

At all ROIs, there were no significant differences in percent change between SPECT and perfusion MRI. Patients with impaired CVR showed significant decreases in the percent changes of respective cerebral blood flow (P=.016) and respective cerebral blood volume (P=.029).

Conclusion

Acetazolamide-challenged perfusion MRI is feasible for evaluating CVR in symptomatic patients with severe MCA stenosis quantitatively.     

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.     

Angioplasty and stenting in carotid dissection with or without associated pseudoaneurysm

BACKGROUND AND PURPOSE: Carotid angioplasty and stent placement may be the preferred treatment in patients with carotid dissection who have failed medical management. The goal of this study was to determine the procedural feasibility and safety as well as long-term complication rates of carotid angioplasty and stent placement in a consecutive cohort of relatively young, high-surgical-risk patients. PATIENTS AND TECHNIQUES: A series of 26 consecutive patients (mean age, 49 years; 15 men and 11 women) who underwent angioplasty and stent placement for carotid dissection with or without pseudoaneurysm from April 1997 to April 2005 at our institution (9 traumatic, 8 spontaneous, and 9 iatrogenic) was retrospectively reviewed. Twenty-eight stents were used in 29 procedures performed on 27 vessels (20 internal carotid arteries and 7 common carotid arteries). Patients were followed with cerebral angiography, CT, sonography, or clinically for a mean of 14.6 months (range, 5 days to 48.2 months) with 17 of 26 patients having at least 6 months of follow-up. Procedural and long-term complication rates were calculated. RESULTS: Dissection-induced stenosis was reduced from 71 +/- 18% to no significant stenosis in 20 of the 21 patients with measurable stenosis. The procedural transient ischemic attack (TIA) rate was 3 of 29 procedures (10.3%). There were no procedural strokes. One patient required angioplasty of a common femoral artery. One procedure was terminated when an asymptomatic new intimal flap was created before intervention. Two patients had occlusions of the treated vessel noted at 22 days (presented with contralateral stroke) and 3.4 months (asymptomatic). There were 2 unrelated deaths from myocardial infarction at 8 days and 15.2 months. Two patients had recurrent ipsilateral TIA at 2.7 months and 12 months. The 30-day occlusion and death rate was 2 of 29 procedures (6.9%). CONCLUSION: In this series, angioplasty and stent placement were effective in relieving stenosis secondary to carotid dissection with or without pseudoaneurysm and have low rates of ischemic complications.