Hyperperfusion syndrome after carotid stent angioplasty

Staged angioplasty: A sensible approach to prevent hyperperfusion syndrome after carotid artery stenting? A meta-analysis

OBJECTIVE

To investigate whether staged angioplasty (SAP) is a safe and effective treatment to prevent hyperperfusion syndrome after carotid artery stenting (CAS).

METHODS

A systematic literature search was performed according to established criteria to identify eligible articles published before October 2020. Pooled dichotomous data were presented as odds ratios (OR) and corresponding 95% confidence intervals (CI) using random-effect models. The efficacy endpoints were hyperperfusion syndrome (HPS), hyperperfusion phenomenon (HPP), and intracerebral hemorrhage (ICH). The safety endpoint was post-procedural thromboembolic events. The feasibility of the procedure was assessed by device-related adverse events (vessel dissection and failed angioplasty) in SAP.

RESULTS

Ten studies (1030 participants) were eligible. SAP was superior to regular CAS in preventing HPS (OR = 0.35, 95% CI 0.14-0.86, P = 0.02). There was no significant difference in the rate of thromboembolic events between the SAP group and the regular CAS group. The rates of vessel dissection and failed angioplasty with the use of a 3.0-mm-diameter balloon were 5.4% and 0.4%, respectively.

CONCLUSION

SAP may reduce the incidence of post-CAS HPS without increasing procedure-related complications. A 3.0-mm-diameter balloon used in SAP may be appropriate for Asian populations. However, the confounded study design and confused definitions of reporting items hinder the current recommendation of SAP in clinical use.

Prevalence and Clinical Predictors of Intracranial Hemorrhage Following Carotid Artery Stenting for Symptomatic Severe Carotid Stenosis

OBJECTIVE

Hyperperfusion-induced intracranial hemorrhage (HICH) is the most frequent cause of death following carotid artery stenting (CAS). This study aimed to identify the presence of HICH after CAS and evaluate demographic and clinical variables associated with HICH.

METHODS

We retrospectively reviewed clinical data of 446 consecutive patients with symptomatic severe carotid stenosis treated with CAS between November 2011 and August 2018. Good collateral compensation was defined as patency of the anterior communicating artery with well-developed bilateral A1 segments with or without posterior communicating arteries, according to the classification of Katano et al. Univariate and multivariate analyses were performed to determine whether there was a correlation between demographic and clinical variables and development of HICH.

RESULTS

Stent placement was successful in all patients. Of 446 patients, 14 had HICH (3.14%); 1 of 14 (7.14%) patients displayed 80%-90% stenosis, and 13 patients had stenosis ≥90%. Thirteen patients (92.86%) had poor collateral circulation compensation. Two patients (14.3%) died despite rescue efforts. Age (≥70 years), degree of carotid artery stenosis (≥90%), and poor compensation of collateral circulation were associated with a higher frequency of HICH after CAS. Severe carotid artery stenosis (≥90%) was independently associated with HICH after stenting (odds ratio 13.633, P = 0.014).

CONCLUSIONS

The incidence rate of HICH was 3.14%. Patients with severe carotid artery stenosis (≥90%) are at high risk for developing HICH after CAS. Further investigations are needed to better describe the contribution of other risk factors, including poor compensation of collateral circulation (especially anterior circulation).

Fatal intracranial hemorrhage after carotid artery stenting: Three case reports and a literature review

INTRODUCTION

We herein describe three patients who developed fatal intracranial hemorrhage (ICH) after carotid artery stenting (CAS).Case Presentation: We retrospectively reviewed 126 patients who underwent CAS from January 2016 to December 2018 and identified 3 patients (2.4%) (all male, mean age of 59 years) who developed ICH after CAS. Two of them developed left basal ganglia hemorrhage with extension into the ventricle and subarachnoid space, and the third patient developed primary ventricular bleeding. One hemorrhage occurred immediately after CAS, whereas the other two occurred 3 hours and 8 hours after the procedure, respectively. The mean stenosis of the treated carotid arteries was 91%. All three hemorrhages were fatal, and the mean time from hemorrhage to death was 50 hours.

CONCLUSION

ICH is a potentially fatal complication of CAS and often occurs several hours after the procedure. Headache, vomiting, and consciousness disorders are the most common symptoms of ICH. Careful screening to identify high-risk patients and strict management of perioperative blood pressure are important to prevent this complication.

The safety and efficacy of staged angioplasty for treating carotid stenosis with a high risk of hyperperfusion: A single-center retrospective study

OBJECTIVE

Hyperperfusion syndrome (HPS) following carotid artery stenting (CAS) is a rare but life-threatening complication. Staged angioplasty (SAP) is an alternative method that prevents HPS by preventing a sudden increase in cerebral blood flow. In this study, we investigated the safety and efficacy of SAP.

METHODS

A total of 114 patients with carotid stenosis underwent CAS treatment in our hospital between September 2014 and September 2019. Patients with severe stenosis and poor collateral circulation shown on digital subtraction angiography (DSA) and hypoperfusion of the ipsilateral diseased blood vessel shown on computed tomography perfusion (CTP) imaging were subjected to SAP treatment (the SAP group), and other patients received regular CAS treatment (the RS group).

RESULTS

Twenty-two patients (19.3%) with a high risk of HPS underwent SAP treatment, 1 of whom had carotid dissection after stage I balloon angioplasty and underwent regular CAS. This patient had HPS after surgery. None of the other patients in either group had HPS. One patient in the SAP group (4.5%) had hyperperfusion phenomenon (HPP) after stage II stenting, and 2 patients in the RS group (2.2%) had HPP. One patient in the SAP group (4.5%) and 4 patients in the RS group (4.3%) had symptomatic ischemic complications postoperatively. None of the differences between the 2 groups were statistically significant. Three patients had reduced modified Rankin Scale (mRS) scores at 90 days after discharge.

CONCLUSION

This research suggests that SAP appears to be an effective method to prevent HPS for patients with a high risk of HPS.

Update on cerebral hyperperfusion syndrome

Cerebral hyperperfusion syndrome (CHS) is a clinical syndrome following a revascularization procedure. In the past decade, neurointerventional surgery has become a standard procedure to treat stenotic or occluded cerebral vessels in both acute and chronic settings, as well as endovascular thrombectomy in acute ischemic stroke. This review aims to summarize relevant recent studies regarding the epidemiology, diagnosis, and management of CHS as well as to highlight areas of uncertainty. Extracranial and intracranial cerebrovascular diseases in acute and chronic conditions are considered. The definition and diagnostic criteria of CHS are diverse. Although impaired cerebrovascular autoregulation plays a major role in the pathophysiology of CHS, the underlying mechanism is still not fully understood. Its clinical characteristics vary in different patients. The current findings on clinical and radiological presentation, pathophysiology, incidence, and risk factors are based predominantly on carotid angioplasty and stenting studies. Hemodynamic assessment using imaging modalities is the main form of diagnosis although the criteria are distinct, but it is helpful for patient selection before an elective revascularization procedure is conducted. After endovascular thrombectomy, a diagnosis of CHS is even more complex, and physicians should consider concomitant reperfusion injury. Management and preventative measures, including intensive blood pressure control before, during, and after revascularization procedures and staged angioplasty, are discussed in detail.

[Tandem occlusions in acute ischemic stroke]

CLINICAL ISSUE

Acute strokes caused by tandem occlusions include an atherosclerotic or dissective stenosis/occlusion of the extracranial internal carotid artery (eICA) in combination with an intracranial vessel occlusion.

STANDARD TREATMENT

Endovascular treatment can be technically challenging but is definitely superior to intravenous thrombolysis alone and achieves good clinical results comparable to those from solitary intracranial occlusions.

LATEST STUDY RESULTS

Although there are still no prospectively randomized studies on endovascular treatment for tandem occlusions, currently available data favor acute stenting of the eACI followed by intracranial thrombectomy.

PURPOSE OF THE ARTICLE

This review discusses endovascular treatment options for tandem occlusions based on currently available data.

Treatment Strategy for Progressive Cervical Internal Carotid Artery Stenosis Under Restriction of the Use of Antiplatelet Drugs

BACKGROUND

Acute ischemic stroke caused by cervical internal carotid artery stenosis (ICS) with altered consciousness and progressive paralysis leads to a poor neurologic prognosis. When such a patient is brought to the hospital in the hyperacute phase, intravenous tissue plasminogen activator is first administered. However, when an indwelling carotid artery stent is required after administration, physicians often hesitate to use antithrombotic drugs. In this report, we propose performing staged angioplasty (SAP) for such cases.

METHODS

Four patients were retrospectively investigated. In all 4 patients, we immediately performed only percutaneous transluminal angioplasty (PTA) without antiplatelet drugs. If both cerebral perfusion on angiography and neurologic findings improved, no additional treatment was provided; otherwise, emergency carotid artery stenting (eCAS) was performed. In PTA-successful cases, eCAS or carotid endarterectomy (CEA) was performed with single or dual antiplatelet drugs at a later date.

RESULTS

The success rate of PTA was 50% (2 of 4), and the overall treatment success rate was 100% (4 of 4). Three patients had favorable outcomes (modified Rankin Scale [mRS] score 0-2), but unfortunately, 1 patient had severe disability (mRS score >3) on discharge. The PTA-successful patients had no perioperative complications. On the other hand, 1 of the 2 patients who underwent eCAS experienced embolic complications, including distal embolization.

CONCLUSIONS

In this investigation, both eCAS and SAP could be performed safety. However, performing SAP first without antiplatelet drugs to avoid hemorrhagic complications and cerebral hyperperfusion syndrome appears to have considerable validity.

Cerebral Hemodynamic Variations in the Early Stage after Carotid Artery Stenting in Patients with and without Near Occlusion

BACKGROUND

To evaluate the unclear cerebral hemodynamic variations in patients with and without near occlusion (NO) in hours after carotid artery stenting (CAS) by transcranial Doppler (TCD).

METHODS

Data of 56 patients (11 patients with carotid artery NO and 45 patients with severe stenosis without NO) who underwent unilateral CAS were analyzed. All patients underwent TCD or transcranial color-code Doppler monitoring before CAS and again at one and three hours after the procedure. We compared bilateral middle cerebral artery peak systolic velocity (MCA-PSV), pulsatility index (PI), and blood pressure (BP) data between the two groups.

RESULTS

Ipsilateral MCA-PSV increased relative to baseline in the stenosis group at one hour (97 ± 30 vs. 84 ± 23 cm/s, 16%, P < 0.001) and three hours (96 ± 28 vs. 84 ± 23 cm/s, 15%, P < 0.001) after CAS. Corresponding increases were distinctly higher in the NO group than in the stenosis group at one hour (116 ± 37 vs. 80 ± 29 cm/s, 51%, P < 0.001) and three hours (113 ± 39 vs. 80 ± 29 cm/s, 46%, P = 0.001) after CAS, whereas BP decreased similarly between the two groups. The ipsilateral PI increased postsurgically in both groups, whereas contralateral MCA-PSV was unaltered.

CONCLUSIONS

CAS can induce a significant increase in PSV and PI in ipsilateral MCA within three hours in patients with NO or severe stenosis but absent NO. The increment of ipsilateral MCA-PSV was greater in patients with NO. TCD can facilitate BP control in the early stage after CAS in patients with NO.

Risk factors for hyperperfusion-induced intracranial hemorrhage after carotid artery stenting in patients with symptomatic severe carotid stenosis evaluation

Background

Analyzing risk factors for hyperperfusion-induced intracranial hemorrhage (HICH) after carotid artery stenting (CAS) in patients with symptomatic severe carotid stenosis.

Methods

This study retrospectively analyzed clinical data of 210 patients, who had symptomatic severe carotid stenosis (70–99%) and received CAS treatment between June 2009 and June 2015, and evaluated the relationship of HICH with patients’ clinical baseline data, imaging features, and treatment strategies.

Results

Seven patients (3.3%) developed HICH after CAS. The incidence of HICH among patients with near total occlusion was significantly higher than among those without (10.1% vs 0%, P<0.001). Out of the seven, five had no development of either anterior or posterior circulations, and two had no development of anterior circulation and poor development of posterior circulation. Results showed that patients with poor compensation of Willis’ Circle were more likely to develop HICH compared with other patients (P<0.001). All patients received preoperative CT perfusion. TTP index was defined as the TTP ratio between the affected and contralateral side. The results showed that the TTP index was significantly different between the HICH group and non-HICH group (1.15±0.10 vs 1.30±0.15, P<0.001). An analysis of the ROC curve indicated that patients with TTP index >1.22 were more likely to develop HICH compared with other patients (sensitivity 100%, specificity 75.9%).

Conclusions

Patients with severe unilateral carotid stenosis, the presence of near total occlusion, poor compensation of Willis’ Circle, and preoperative TTP index>1.22, have a higher risk of developing HICH after CAS.

Staged carotid artery angioplasty and stenting for patients with high-grade carotid stenosis with high risk of developing hyperperfusion injury: a retrospective analysis of 44 cases

Background

Hyperperfusion syndrome (HPS) is a rare but potentially a life-threatening complication after carotid artery angioplasty and stenting (CAS). Staged CAS has been an alternative to prevent HPS.

Materials and methods

44 of 908 patients with high-grade internal carotid artery stenosis or near occlusion were at risk of HPS because of poor collateral flow and impaired cerebral blood flow (CBF). They were treated with first (stage 1), followed by a full CAS (stage 2) 1 month later. Their 30-day outcomes were tabulated and analysed.

Results

During follow-up, 1 of the 44 (2.2%) patients developed HPS immediately, 3 (7%) had postprocedural HPS (ie, transcranial Doppler (TCD) >120%) without clinical symptoms and 3 (7%) required stenting at stage 1 for carotid dissections. After stage 1, there were significant improvement between the preprocedural and postprocedural CBF (0.98±0.06 vs 0.85±0.05, p<0.05), mean transit time (MTT; 1.05±0.05 vs 1.15±0.05, p<0.05), time to peak (TTP; 1.04±0.06 vs 1.20±0.06, p<0.05) on CT perfusion (CTP), and CBF (66.41±7.41 vs 44.44±6.43, p<0.05) on TCD. After stage 2, improvement was seen in CBF (1.01±0.07 vs 0.98±0.06, p<0.05), MTT (1.01±0.05 vs 1.05±0.05, p<0.05), TTP (0.99±0.06 vs 1.04±0.06, p<0.05) on CTP and CBF (66.41±7.41 vs 93.78±18.81, p<0.05) on TCD. 2 had postoperative increase of middle cerebral artery mean flow velocity of 120% after stage 2 without clinical symptoms.

Conclusion

Staged carotid artery stenting probably decreased the chance of developing HPS in this group of selected patients. Although requiring a 2-step intervention, staged CAS may be a safe and effective alternative.

Hyperperfusion Syndrome After Stenting for Intracranial Artery Stenosis

Hyperperfusion syndrome (HPS) is a rare but potentially devastating postoperative complication developing after endarterectomy and carotid stenting. Limited information is available about this complication. The aim of this study was to assess the incidence of HPS and risk factors leading to its development. We retrospectively reviewed 178 consecutive cases of patients who underwent stenting of intracranial artery revascularization. We analyzed the association between HPS and patient's age, collateral vascular supply of the lesion, the interval between operation and the last occurrence of ischemic symptom, adequacy of blood pressure control after the operation, and other risk factors such as diabetes, smoking, hypertension, and gender. Of 178 included patients, we found HPS in six cases (3.4%). Failure to strictly control postoperative blood pressure, a less than 3-week long interval between operation and the last occurrence of ischemic symptom, and poor collateral circulation were significantly associated with the development of HPS. The aforementioned factors are predictors for HPS. We argue that nitroprusside should not be used to control blood pressure after the operation because its use permits considerable blood pressure fluctuations.

[Endovascular treatment of acute extracranial carotid artery occlusion]

Acute extracranial internal carotid artery (ICA) occlusions resulting in ischemic stroke are different from other forms of acute occlusions of cerebral vessels. The pathophysiological process involved in occlusion of the extracranial ICA is similar to processes observed in acute occlusion of the coronary arteries. The occluded segment of the ICA predominantly consists of an atherosclerotic plaque and a superimposed thrombus. Although the value of endovascular therapy has been established for intracranial occlusions, the acute treatment of extracranial ICA occlusions has not yet been proven in randomized studies. In these patients primary stenting of acute extracranial occlusions of the ICA is a treatment option with good clinical results. This review discusses the endovascular treatment of acute extracranial ICA occlusions.

Leptomeningeal collateral vessels are a major risk factor for intracranial hemorrhage after carotid stenting in patients with carotid atherosclerotic plaque

AIM

To evaluate the relationship between leptomeningeal collaterals and intracranial hemorrhage (ICH) after carotid artery stenting (CAS).

METHODS

A retrospective study was undertaken of 228 patients (median age 75 years (range 44-90); 187 men and 41 women) who underwent CAS due to unilateral carotid atherosclerotic plaque from January 2009 to December 2013. Cerebral angiographic findings were classified into three patterns: type I, normal visualization of the anterior and middle cerebral arteries without leptomeningeal collaterals; type II, visualization of the middle cerebral artery only without leptomeningeal collaterals; and type III, visualization of leptomeningeal collateral flow.

RESULTS

For all cerebral angiographic findings, 146 (64.0%) were type I, 61 (26.8%) were type II, and 21 (9.2%) were type III. Four patients (1.8%) died with fatal ICH after CAS and had type III angiographic findings (19%). The prevalence of ICH in patients with leptomeningeal collateral vessels was significantly higher than in patients without leptomeningeal collateral vessels (19% vs 0%, p<0.0001). The percentage of carotid stenosis in patients with ICH based on North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria was significantly higher than in patients without ICH (89.8±3.6% vs 72.8±12.8%, p=0.014).

CONCLUSIONS

Leptomeningeal collateral vessels are a major risk factor for ICH after CAS in patients with carotid atherosclerotic plaque.

Intraprocedural detection of cerebral hyperperfusion by flat detector computed tomography in the evaluation of cerebral blood volume during carotid artery stenting. A case report

Cerebral blood volume (CBV) can be measured using a C-arm flat detector angiographic system. The present report describes a case in which cerebral hyperperfusion was detected with the Neuro parenchymal blood volume (PBV) system (syngo Neuro PBV IR, Siemens Medical Solutions, Erlangen, Germany) during carotid artery stenting (CAS). An 89-year-old man was referred to our hospital for cerebral brain infarction and severe stenosis of the left carotid artery. CAS was performed, and Neuro PBV was used to measure CBV both during and after the procedure. Postoperative Neuro PBV revealed dramatically increased CBV, and a hyperperfusion state was suspected. The next day, subarachnoid hemorrhage along the sulcus of the left hemisphere was revealed on computed tomography. Strict management of blood pressure was instituted just after the detection of hyperperfusion, and the patient was ultimately discharged from the hospital without any new neurological deficits. Neuro PBV has the advantage that it can be performed in the angiography suite and does not require patient transfer to an alternate setting. Therefore, intracranial hemodynamic changes can be detected during the procedure. We conclude that the Neuro PBV system is useful for monitoring intracranial hemodynamics during endovascular procedures.

Dilation of the Internal Carotid Artery at the Entrance to the Carotid Canal following Carotid Artery Stenting Predicts Postprocedural Hyperperfusion

OBJECTIVE

Ischemic stroke and hyperperfusion (HP) are the most frequent and important complications in carotid artery stenosis surgery. Carotid artery stenting (CAS) has replaced carotid endarterectomy in high medical risk patients. Prior to CAS, initial angiographic findings disclose a small caliber internal carotid artery (IC) due to stenosis, but after the stenosis is relieved, the diameter of the IC becomes enlarged. We investigated whether a change in the IC diameter was related to ischemic complication and HP using cerebral blood flow single photon emission computed tomography (SPECT).

METHODS

From February 2008 to December 2009 we consecutively performed 39 CAS on 35 patients. We retrospectively analyzed the relationship between changes at the level before the entry to the petrous bone canal of the IC and stenosis of the etiological artery, improvement in stenosis, HP and postintervention diffusion-weighted image high-intensity lesions. Statistical analyses comprised Wilcoxon/Kruskal-Wallis analysis, analysis of variance and a multivariate logistic analysis.

RESULTS

A total of 9 cases showed HP in SPECT. Severity of IC stenosis and change in the IC at the level before the entry to the petrous bone canal were related with statistical significance to HP. Other factors did not correlate with HP.

CONCLUSION

Procedure-related dilation of the IC at the level before the entry to the petrous bone canal occurred due to release of the etiological stenosis. This finding can also support the prediction of HP.

[Carotid artery stenting technique]

Over the past 25 years carotid artery stenting (CAS) has emerged as an alternative to carotid endarterectomy (CEA). Most of all younger patients and symptomatic patients with contralateral carotid artery occlusion particularly benefit from CAS. To achieve an optimal result with CAS, patient selection and even more important, knowledge and experience of the interventionist is crucial. The periprocedural complication rate of CAS in large experienced centers is lower (2-3%) than those in randomized trials. Several different devices are now available which allow the procedure to be tailored according to patient anatomy and lesion complexity. Complications like hyperperfusion syndrome and intracerebral bleeding, rupture of side branches of the external or internal carotid artery as well as problems caused by slow flow can be widely avoided by adequate experience.

Bilateral Superior Cerebellar Artery Infarction after Stent-Angioplasty for Internal Carotid Artery Stenosis

Spontaneous bilateral cerebellar infarction in the territory of the superior cerebellar arteries is extremely rare. Occasionally there have been reports of bilateral cerebellar infarction due to vertebrobasilar atherosclerotic occlusion or stenosis, whereas no report of bilateral cerebellar infarction due to complicated hemodynamic changes. In this report, we present a patient with bilateral cerebral infarctions related to stenoses of bilateral internal carotid arteries, in whom vertebrobasilar system was supplied by multiple collaterals from both posterior communicating arteries and right external carotid artery. We performed stent-angioplasty of bilateral internal cerebral arterial stenosis, and then acute infarction developed on bilateral superior cerebellar artery territories. The authors assumed that the infarction occurred due to hemodynamic change between internal carotid artery and external carotid artery after stent-angioplasty for stenosis of right internal carotid artery.

Carotid artery stenting in acute stroke

OBJECTIVES

The purpose of this study is to demonstrate the technical success of carotid artery stenting in acute extracranial internal carotid artery (ICA) occlusion as well as the benefit in clinical outcome.

BACKGROUND

Stroke caused by acute occlusion of the ICA is associated with a significant level of morbidity and mortality. For this type of lesion, treatment with standard intravenous thrombolysis alone leads to a good clinical outcome in only 17% of the cases, with a death rate as high as 55%. Recanalization of the occluded ICA can lead to an improvement in acute symptoms of stroke, prevent possible deterioration, and reduce long-term stroke risk. At present, there is no consensus treatment for patients with acute ischemic stroke presenting with severe clinical symptoms due to atherosclerotic occlusion of the extracranial ICA.

METHODS

Carotid artery stenting was performed in 22 patients with acute atherosclerotic extracranial ICA occlusion within 6 h of stroke symptom onset. In 18 patients, there was an additional intracranial occlusion at the level of the terminal segment of the ICA (n = 4) and at the level of the middle cerebral artery (n = 14). Intracranial occlusions were either treated with the Penumbra system or the Solitaire stent-based recanalization system, or a combination of mechanical recanalization and intra-arterial thrombolysis. Recanalization results were assessed by angiography immediately after the procedure. The neurologic status was evaluated before and after the treatment with a follow-up as long as 90 days using the National Institutes of Health Stroke Scale and the modified Rankin Scale.

RESULTS

Successful revascularization of extracranial ICA with acute stent implantation was achieved in 21 patients (95%). There was no acute stent thrombosis. After successful recanalization of the origin of the ICA, the intracranial recanalization with Thrombolysis In Myocardial Infarction flow grade 2/3 was achieved in 11 of the 18 patients (61%). The overall recanalization rate (extracranial and intracranial) was 14 of 22 patients (63%). Nine patients (41%) had a modified Rankin Scale score of ≤2 at 90 days. The mortality rate was 13.6% at 90 days.

CONCLUSIONS

Carotid artery stenting in acute atherosclerotic extracranial ICA occlusion with severe stroke symptoms is feasible, safe, and useful within the first 6 h after symptom onset.

The hyperintense acute reperfusion marker on fluid-attenuated inversion recovery magnetic resonance imaging is caused by gadolinium in the cerebrospinal fluid

BACKGROUND AND PURPOSE

The hyperintense acute reperfusion marker (HARM) on fluid-attenuated inversion recovery MRI is believed to be caused by gadolinium-based contrast agents crossing a disrupted blood-brain barrier. However, this hypothesis has never been directly verified in humans.

METHODS

In this study, we analyzed cerebrospinal fluid samples of patients with HARM on imaging regarding the presence and concentration of gadolinium-based contrast agents.

RESULTS

Gadobutrol was found in concentrations of approximately 50 μmol/L. Using phantom MRI experiments, we demonstrate that the detected concentrations are consistent with the observed HARM imaging pattern.

CONCLUSIONS

Our study yields first direct evidence in humans that the imaging phenomenon HARM is indeed caused by leakage of gadolinium-based contrast agents into the cerebrospinal fluid.

[Transient monoparesis of the right arm after carotid artery stenting]

We report on an 80-year-old hypertensive patient with a left-sided high-grade carotid stenosis who developed transient monoparesis of the right arm after stenting of the carotid artery. Computed tomography (CT) of the brain (cranial CT) performed immediately after the symptomatic had begun showed a linear hyperdensity in the ipsilateral, precentral sulcus with a moderate, local brain swelling and edema. Transcranial doppler sonography revealed an accelerated post-interventional systolic blood flow velocity and in the ipsilateral medial cerebral artery compared to the preoperative value and an increased cerebral blood flow, so that the diagnosis of hyperperfusion syndrome with a subpial hematoma was confirmed. After strict blood pressure control and -reduction the neurological deficit regressed gradually and the hyperdensity had completely disappeared in control CCT after 15 h.

Treatment and outcome of intracranial hemorrhage after carotid artery stenting. A ten year single center experience

SUMMARY

Intracranial hemorrhage following carotid artery stenting (CAS) is a rare but potentially devastating complication. The present study reviewed intracranial hemorrhage cases from patients undergoing CAS in ten years to find the methods to rescue patients from this fatal complication. Patients with postoperative intracranial hemorrhage following CAS were retrospectively selected, and clinical features, treatments and outcomes were studied. Ten patients with intracranial hemorrhage were identified. The mean onset time of hemorrhage was 6.1-/+7.1h. Intracerebral hemorrhage occurred in eight patients and SAH in two patients. The patients were treated by stopping anti-platelet and anticoagulant for at least three days, and surgical drainage of the hematoma/ventricle drainage or conservative treatment. Six patients survived, two had left moderate paralysis, four had a good recovery at four week follow-up, and four patients died. No patients underwent thrombosis in stent after withdrawing of antiplatelet and anticoagulant. Intracranial hemorrhage after CAS occurs usually in a few hours and leads to catastrophic results. Once patients have intracranial hemorrhage, good neurocritical care may help to save them. Stopping antiplatelet and anticoagulant for at least three days may avoid thrombosis in the stenting site.