Intracranial hemorrhage associated with cerebral hyperperfusion syndrome following carotid endarterectomy and carotid artery stenting: retrospective review of 4494 patients

Hybrid Surgery for symptomatic chronic internal carotid artery occlusion: a single-center experience

BACKGROUND

Patients with symptomatic chronic internal carotid artery occlusion (ICAO) face a high risk of recurrent stroke despite receiving aggressive medical therapy. This study aimed to evaluate the effectiveness and safety of hybrid surgery in treating symptomatic chronic ICAO.

METHODS

This retrospective case series was conducted at a single center. From January 2019 to December 2022, patients with symptomatic chronic ICAO who underwent hybrid surgery were included. We collected baseline data, lesion characteristics, revascularization rates, perioperative complications, and follow-up outcomes.

RESULTS

The study enrolled 27 patients, comprising 22 males and 5 females, with symptomatic chronic ICAO. The hybrid surgery achieved a technical success rate of 100% for revascularization (n = 27), with a perioperative complication rate of 14.8% (n = 4). Following a median follow-up of 6.0 months (IQR, 4-10), 21 patients underwent a DSA or CT angiography reexamination, confirming a vascular patency rate of 90.5% (n = 19). One patient required surgery for severe in-stent restenosis, and another experienced asymptomatic occlusion. Clinical follow-ups were conducted for all 26 patients; no new strokes were reported in the qualifying artery territory, with 13 patients scoring 0, 12 scoring 1, and 1 scoring 2 on the mRS.

CONCLUSION

Although hybrid surgery represent a promising option for treating chronic ICAO, they are also associated with a relatively high incidence of treatment-related complications. The application of composite surgery should be based on standardized technical guidelines and the careful selection of patients who are genuinely at high risk for recurrent strokes.

Development and validation of a nomogram for cerebral hemorrhage in patients with carotid stenosis undergoing stenting: a multicenter retrospective study

BACKGROUND

Hyperperfusion-induced cerebral hemorrhage (HICH) is a rare but severe complication in patients with carotid stenosis undergoing stent placement for which predictive models are lacking. Our objective was to develop a nomogram to predict such risk.

METHODS

We included a total of 1226 patients with carotid stenosis who underwent stenting between June 2015 and December 2022 from three medical centers, divided into a development cohort of 883 patients and a validation cohort of 343 patients. The model used LASSO regression for feature optimization and multivariable logistic regression to develop the predictive model. Model accuracy was assessed via the receiver operating characteristic curve, with further evaluation of calibration and clinical utility through calibration curves and decision curve analysis (DCA). The model underwent internal validation using bootstrapping and external validation with the validation cohort.

RESULTS

Older age (OR 1.07, p=0.005), higher degrees of carotid stenosis (OR 1.07, p=0.006), poor collateral circulation (OR 6.26, p<0.001), elevated preoperative triglyceride levels (OR 1.27, p=0.041) and neutrophil counts (OR 1.36, p<0.001) were identified as independent risk factors for HICH during hospitalization. The nomogram constructed based on these predictive factors demonstrated an area under the curve (AUC) of 0.817. The AUCs for internal and external validation were 0.809 and 0.783, respectively. Calibration curves indicated good model fit, and DCA confirmed substantial clinical net benefit in both cohorts.

CONCLUSION

We developed and validated a nomogram to predict HICH in patients with carotid stenosis post-stenting, facilitating early identification and preventive intervention in high-risk individuals.

Early Detection of hyperemia with Magnetic Resonance Fluid Attenuation Inversion Recovery Imaging after Superficial Temporal Artery to Middle Cerebral Artery Anastomosis

OBJECTIVE

Cerebral hyperperfusion syndrome (CHS) manifests as a collection of symptoms brought on by heightened focal cerebral blood flow (CBF), afflicting nearly 30% of patients who have undergone superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis. The aim of this study was to investigate whether the amalgamation of magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) and apparent diffusion coefficient (ADC) imaging via MRI can discern cerebral hyperemia after STA-MCA anastomosis surgery.

METHODS

A retrospective study was performed of patients who underwent STA-MCA anastomosis due to Moyamoya disease or atherosclerotic steno-occlusive disease. A protocol aimed at preventing CHS was instituted, leveraging the use of MRI FLAIR. Patients underwent MRI diffusion with FLAIR imaging 24 hours after STA-MCA anastomosis. A high signal on FLAIR images signified the presence of hyperemia at the bypass site, triggering a protocol of hyperemia care. All patients underwent hemodynamic evaluations, including perfusion MRI, single-photon emission computed tomography (SPECT), and digital subtraction angiography, both before and after the surgery. If a high signal intensity is observed on MRI FLAIR within 24 hours of the surgery, a repeat MRI is performed to confirm the presence of hyperemia. Patients with confirmed hyperemia are managed according to a protocol aimed at preventing further progression.

RESULTS

Out of a total of 162 patients, 24 individuals (comprising 16 women and 8 men) exhibited hyperemia on their MRI FLAIR scans following the procedure. SPECT was conducted on 23 patients, and 11 of them yielded positive results. All 24 patients underwent perfusion MRI, but nine of them showed no significant findings. Among the patients, 10 displayed elevations in both CBF and cerebral blood volume (CBV), three only showed elevation in CBF, and two only showed elevation in CBV. Follow-up MRI FLAIR scans conducted 6 months later on these patients revealed complete normalization of the previously observed high signal intensity, with no evidence of ischemic injury.

CONCLUSION

The study determined that the use of MRI FLAIR and ADC mapping is a competent means of early detection of hyperemia after STA-MCA anastomosis surgery. The protocol established can be adopted by other neurosurgical institutions to enhance patient outcomes and mitigate the hazard of permanent cerebral injury caused by cerebral hyperemia.

Focal Non-aneurysmal Subarachnoid Hemorrhage After Carotid Artery Stenting: A Case Report

Minor non-aneurysmal subarachnoid hemorrhage (SAH) following carotid artery stenting (CAS) is exceedingly rare and less described, with its underlying mechanism elusive. Here, we present the case of a 75-year-old female who underwent CAS for progressive asymptomatic severe stenosis of the internal carotid artery. Her post-procedural course remained uneventful, with no intracranial hemorrhage detected on the following day's magnetic resonance imaging (MRI). However, a routine MRI on the seventh post-procedural day identified a small amount of SAH in the central sulcus on the operative side. In the absence of symptoms, the patient was discharged home after a computed tomography (CT) scan revealed no signs of hemorrhagic enlargement the following day. In this report, we document the rare occurrence of localized SAH post-CAS. There are limited reports of minor SAH following CAS, with the underlying mechanisms remaining unclear. In this report, the localization of SAH aligns with the most critical ischemic sites, indicating that the mechanism of focal SAH after CAS is associated with blood-brain barrier (BBB) disruption due to a rapid increase in blood flow to small vessels with impaired vascular autoregulation. Focal convexity SAH is an easily overlooked finding, and the medical team performing carotid artery revascularization procedures should be aware of the potential for such SAH postoperatively and exercise caution during postoperative imaging interpretation.

A case report of the treatment of carotid artery stenosis by staged angioplasty based on intraoperative TCD monitoring

Objective

Cerebral hyperperfusion syndrome (CHS) is the most severe complication of carotid artery stenting (CAS) or endarterectomy (CEA). Staging treatment can effectively reduce the risk of CHS without increasing the risk of ischemic stroke. The first stage of balloon dilatation is critical for staged treatment. However, the successful criterion of the first stage balloon dilatation is still inconsistent.

Method

In the current study presents a case of a 61-year-old male with bilateral internal carotid subtotal occlusion, transcranial doppler (TCD) was used to measure middle cerebral artery (MCA) flow rate on the narrow side of surgery and the results are promising.

Result

Intraoperative TCD monitoring is expected to be an evaluation criterion for staged angioplasty for carotid artery stenosis.

Conclusion

The approach of blood flow velocity in the brain based on intraoperative measurement of TCD during the treatment of this patient is a new idea for staging treatment in the future.

Safety and Risk Factors of Carotid Artery Stenting with Simple Distal Filter Protection: A Single-Center Retrospective Study

Objective

Carotid artery stenting embolic protection devices offer various options, among which distal filter protection is the simplest and easiest to handle. However, compared to balloon protection systems, distal filter protection has more embolic complications. Therefore, we explored the risk factors of distal filter protection, intending to achieve a safer carotid artery stenting. This retrospective study was conducted to identify prognostic factors following carotid artery stenting with only distal filter protection from July 2010 to June 2021.

Methods

Information on patient background, procedures and devices, and complications was collected using medical records. The data pertaining to 187 patients were analyzed after excluding the data of patients in whom other protection devices (8 cases) were used. We used FilterWire EZ as the first choice for embolic protection device and SpiderFX when the patients had difficult-to-cross lesions.

Results

The patients' mean age was 71.9 ± 6.9 years, and 72 (38.5%) were symptomatic. Symptomatic (odds ratio: 2.02, p = 0.035) and difficult-to-cross lesions (odds ratio: 3.63, p = 0.0013) were factors independently associated with symptomatic complications.

Conclusion

This retrospective single-center study established independent prognostic factors for carotid artery stenting with distal filter protection. For patients with symptomatic lesions and severe stenosis or bends that are difficult to pass through, it is necessary to be careful when performing carotid artery stenting with distal filter protection.

Perioperative stroke

Ischaemic or haemorrhagic perioperative stroke (that is, stroke occurring during or within 30 days following surgery) can be a devastating complication following surgery. Incidence is reported in the 0.1-0.7% range in adults undergoing non-cardiac and non-neurological surgery, in the 1-5% range in patients undergoing cardiac surgery and in the 1-10% range following neurological surgery. However, higher rates have been reported when patients are actively assessed and in high-risk populations. Prognosis is significantly worse than stroke occurring in the community, with double the 30-day mortality, greater disability and diminished quality of life among survivors. Considering the annual volume of surgeries performed worldwide, perioperative stroke represents a substantial burden. Despite notable differences in aetiology, patient populations and clinical settings, existing clinical recommendations for perioperative stroke are extrapolated mainly from stroke in the community. Perioperative in-hospital stroke is unique with respect to the stroke occurring in other settings, and it is essential to apply evidence from other settings with caution and to identify existing knowledge gaps in order to effectively guide patient care and future research.

Risk Factors for Cerebral Hyperperfusion Syndrome following Carotid Revascularization

BACKGROUND

Cerebral hyperperfusion syndrome (CHS) is a rare but known complication of carotid revascularization that can result in severe postoperative disability and death. CHS is a well-described sequela of carotid endarterectomy (CEA) and, more recently, of transfemoral carotid artery stenting (TFCAS), but its incidence after transcarotid artery revascularization (TCAR) has not been delineated. The aims of this study were to determine the impact of procedure type (CEA versus TCAR versus TFCAS) on the development of CHS as well as to identify perioperative risk factors associated with CHS.

METHODS

The Society for Vascular Surgery Vascular Quality Initiative was queried for patients aged ≥18 years who underwent CEA, TCAR, or TFCAS from 2015-2021. Emergent procedures were excluded. The primary outcome was postoperative development of CHS, defined as the presence of postoperative seizures, intracerebral hemorrhage due to hyperperfusion, or both. Bivariate and multivariable logistic regression analyses were performed to identify factors associated with CHS.

RESULTS

156,003 procedures were included (72.7% CEA, 12.4% TCAR, and 14.9% TFCAS). The incidence of CHS after CEA, TCAR, and TFCAS were 0.15%, 0.18%, and 0.53%, respectively. There was no significant difference in risk of CHS after TFCAS compared to CEA (odds ratio [OR]: 1.21; 95% confidence interval [CI] 0.76-1.92; P = 0.416), nor was there a difference between TCAR and CEA (OR: 0.91; 95% CI 0.57-1.45; P = 0.691). Perioperative risk factors associated with an increased risk of CHS included previous history of transient ischemic attack or stroke (OR: 2.50; 95% CI 1.69-3.68; P < 0.0001), necessity for urgent intervention within 48 hr (OR: 2.03; 95% CI 1.43-2.89; P < 0.0001), treatment of a total occlusion (OR: 3.80; 95% CI 1.16-12.47; P = 0.028), and need for postoperative intravenous blood pressure medication (OR: 5.45; 95% CI 3.97-7.48; P < 0.0001). Age, preoperative hypertension, degree of ipsilateral stenosis less than or equal to 99%, and history of prior carotid procedures were not statistically associated with an increased risk of CHS. Discharging patients on an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker was associated with a decreased risk of developing CHS (OR: 0.47; 95% CI 0.34-0.65; P < 0.0001).

CONCLUSIONS

Compared with CEA, TCAR and TFCAS were not statistically associated with an increased risk of postoperative CHS. Patients with a previous history of transient ischemic attack or stroke, who require urgent intervention or postoperative intravenous blood pressure medication, or who are treated for a total occlusion are at a higher risk of developing CHS. Using an angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker on discharge appears to be protective against CHS and should be considered for the highest risk patients.

Complications and outcomes of carotid artery stenting in high-risk cases

OBJECTIVES

Carotid artery stenting is sometimes adapted for some at-risk cases; however, appropriate treatment timing with stroke onset is controversial. This study aims to identify factors that have an impact on complications and outcomes, especially in patients at high risk.

MATERIALS AND METHODS

We examined the characteristics of 152 consecutive patients treated by carotid artery stenting between January 2018 and March 2022 and retrospectively analyzed the risk factors for complications and poor outcomes (modified-Rankin-Scale deterioration), such as patient background, carotid artery stenting risks (access route tortuosity, severe calcification, vulnerable plaque, estimated glomerular filtration rate <30 mL/min/1.73 m2, etc.), characteristics of the stenosis, details of treatment, and treatment timing.

RESULTS

The average North American Symptomatic Carotid Endarterectomy Trial criteria score was 68.3% and the lesion length was 20.5±9.7mm. Among patients, 107 (70.4%) had a carotid artery stenting risk. In high-risk carotid artery stenting cases, symptomatic complications occurred in 32 (30.0%), and the 90-day modified Rankin scale score deteriorated in 15 cases (14.0%). Multivariate analysis showed that cases with triple antithrombotic therapy (p=0.003), stenting within 7 days (p=0.0032), and after 28+ days (p=0.0035) of stroke onset were independently associated factors for complications.

CONCLUSIONS

This study showed that among risk factors, triple antithrombotic therapy in particular was a risk factor for perioperative complications. Carotid artery stenting for patients with stroke after 28 days of onset affects the prognosis. Therefore, although further study is warranted, waiting more than one month for treatment in patients requiring carotid artery stenting is a potential risk.

History of Carotid Artery Reconstruction around the World and in Japan

Since ancient times, physicians have been aware of correlations between the carotid artery and consciousness; however, carotid stenosis was only recently identified as the cause of atherothrombotic ischemic stroke. In 1658, Wepfer described the first suggestion of a link between symptoms of cerebral arterial insufficiency and carotid pathology. In 1951, Fisher reported details of the symptoms and pathological findings and emphasized that cervical atheromatous lesions induced cerebral infarction with various symptoms. The beginning of carotid artery surgery was ligation of the carotid artery for neck or head injury, but surgeons were aware that this operation induced cerebral symptoms due to lack of blood supply. Carotid endarterectomy (CEA) was first reported by Eastcott et al. in 1954, and in Japan, Kimoto performed a successful CEA in 1962. In 1979, percutaneous transluminal angioplasty (PTA) was performed for patients with fibromuscular dysplasia, and then, carotid artery stenting (CAS) was first performed in 1989 by Mathias. In Japan, Kuwana et al. were the first to perform carotid PTA, in 1981, whereas Yamashita et al. performed the first CAS in 1997. Yoshimura et al. proposed staged carotid stenting to prevent hyperperfusion syndrome. Some issues in carotid reconstruction are still debated today, which include conventional (standard) CEA versus the eversion technique, CEA versus CAS versus medical therapy, and medical economic problems. In the future, we must continue to develop more effective, safer, and less expensive therapeutic methods to prevent carotid stroke, carrying on the efforts of the ancient peoples who pioneered this research.

Nonconvulsive Status Epilepticus Associated with Cerebral Hyperperfusion Syndrome after Carotid Endarterectomy: A Case Report

We report a case of a 73-year-old man who developed nonconvulsive status epilepticus as a complication of cerebral hyperperfusion syndrome after carotid endarterectomy for carotid artery stenosis. On postoperative day 1, the patient experienced headaches and vomiting. Resting N-isopropyl-p-[¹²³I] iodoamphetamine single-photon emission computed tomography showed increased cerebral blood flow to the entire right hemisphere, and the patient was diagnosed with cerebral hyperperfusion syndrome. He was treated with antihypertensive and antiseizure medications, sedated using propofol, intubated, and placed under mechanical ventilation. On postoperative day 3, computed tomography perfusion imaging showed a reduction in hyperperfusion, and propofol sedation was terminated on postoperative day 4. However, the patient exhibited prolonged impaired awareness and roving eye movements, and long-term video electroencephalographic monitoring revealed electrographic seizures. The patient was diagnosed with nonconvulsive status epilepticus. Propofol sedation was resumed, and the antiseizure medication dose was increased. Subsequently, the state of hyperperfusion in the right hemisphere diminished, and electroencephalographic findings improved, allowing sedation to be terminated on postoperative day 7. The findings from this case suggest that when clinical subtle symptoms, such as impaired awareness and roving eye movements, are observed during treatment of cerebral hyperperfusion syndrome, video electroencephalography should be performed to detect electrographic seizures.

Non responsible vascular area hyperperfusion syndrome after mechanical thrombectomy for vertebral artery occlusion: A case report

Introduction

There are currently no published reports of hyperperfusion syndrome in the non responsible vascular area after mechanical thrombectomy for acute cerebral infarction with large vessel occlusion. Here, we report a case of hyperperfusion syndrome in the blood supply area of the right middle cerebral artery after mechanical thrombectomy for acute cerebral infarction after vertebral artery occlusion.

Patient concerns

A 21-year-old woman developed left vertebral artery occlusion, for which she received mechanical thrombectomy and successful recanalization of her occluded cerebral vessel. Subsequently, the patient became extremely agitated, with high blood pressure and headache.

Diagnosis

Two hours after the operation, bedside transcranial Doppler ultrasound examination found that the cerebral blood flow velocity of the M1 segment of the right middle cerebral artery was more than twice that of the left middle cerebral artery. Combined with the symptoms, signs and examination results of the patient, hyperperfusion syndrome in the blood supply area of the right middle cerebral artery was considered.

Interventions

The patient was administered sedation, and her pressure and ventricular rate were strictly controlled. She was no longer agitated, and her headache was significantly relieved at 36 hours after the operation.

Outcomes

On the 5th day after the operation, the blood flow velocity of her right middle cerebral artery decreased to normal level, and the patient recovered well.

Conclusion

In this case, after mechanical thrombectomy, such patients with acute posterior circulation cerebral infarction can experience hyperperfusion syndrome in the non responsible vascular area of the anterior circulation. Bedside transcranial Doppler cerebral blood flow examination can identify the hyperperfusion state of cerebral vessels in a timely manner and effectively guide treatment.

Application of laser speckle flowgraphy to evaluate cerebral perfusion after carotid endarterectomy

Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy (CEA) is devastating, and postoperative monitoring of cerebral perfusion is essential to prevent CHS. We report two cases of successful measurement of ocular blood flow using laser speckle flowgraphy (LSFG) for bedside assessment of the changes in cerebral perfusion after CEA. An 18.7% (case 1) and 47.7% (case 2) increase in ocular blood flow were measured postoperatively using LSFG compared with the baseline. LSFG might be applicable to evaluate cerebral perfusion after CEA.

Prediction of cerebral hyperperfusion following carotid endarterectomy using intravoxel incoherent motion magnetic resonance imaging

OBJECTIVES

One of the risk factors for cerebral hyperperfusion following carotid endarterectomy (CEA) is a chronic reduction in cerebral perfusion pressure due to internal carotid artery (ICA) stenosis, which is clinically detected as increased cerebral blood volume (CBV). The perfusion fraction (f) is one of the intra-voxel incoherent motion (IVIM) parameters obtained using magnetic resonance (MR) imaging that theoretically reflects CBV. The present study aimed to determine whether preoperative IVIM-f on MR imaging predicts development of cerebral hyperperfusion following CEA.

MATERIALS AND METHODS

Sixty-eight patients with unilateral ICA stenosis (≥ 70%) underwent preoperative diffusion-weighted 3-T MR imaging, and IVIM-f maps were generated from these data. Quantitative brain perfusion single-photon emission computed tomography (SPECT) was performed before and immediately after CEA. Regions-of-interest (ROIs) were automatically placed in the bilateral middle cerebral artery territories in all images using a three-dimensional stereotactic ROI template, and affected-to-contralateral ratios in the ROIs were calculated on IVIM-f maps.

RESULTS

Nine patients (13%) exhibited postoperative hyperperfusion (cerebral blood flow increases of ≥ 100% compared with preoperative values in the ROIs on brain perfusion SPECT). Only high IVIM-f ratios were significantly associated with the occurrence of postoperative hyperperfusion (95% confidence interval, 253.8-6774.2; p = 0.0031) on logistic regression analysis. The sensitivity, specificity, and positive and negative predictive values of the IVIM-f ratio to predict the occurrence of postoperative hyperperfusion were 100%, 81%, 45%, and 100%, respectively.

CONCLUSIONS

Preoperative IVIM-f on MR imaging can predict development of cerebral hyperperfusion following CEA.

Effect of perioperative blood pressure variability on cerebral hyperperfusion syndrome after carotid artery stenting: A retrospective study

OBJECTIVE

To investigate the effect of perioperative blood pressure variability on cerebral hyperperfusion syndrome after carotid artery stenting.

METHODS

A retrospective analysis was conducted of data collected from 418 patients who underwent carotid artery stenting in Guangxi Zhuang Autonomous Region People's Hospital in China. The blood pressure data were collected during operation (after balloon dilation, before stent release, after stent release) and within 3 days after the operation. The blood pressure variability was evaluated by measuring the mean, maximum, minimum, max-min, standard deviation (SD) of systolic blood pressure (SBP) and diastolic blood pressure (DBP). The correlation between blood pressure variability and cerebral hyperperfusion syndrome was analysed.

RESULTS

Blood pressure data from 418 patients were analysed. Twenty patients (4.8%) developed cerebral hyperperfusion syndrome. The parameters of blood pressure variability were divided into four groups according to quartile. After adjusting for age, symptomatic carotid stenosis, unilateral carotid stenosis, bilateral carotid stenosis, collateral circulation, diabetes mellitus and chronic kidney disease, multivariate analysis showed that SBPMax, SBPMin, SBPMax-Min, SBPCV, DBPSD, DBPMax, DBPMin, DBPMax-Min and DBPCV were associated with the occurrence of cerebral hyperperfusion syndrome (P < 0.05), respectively.

CONCLUSION

This study suggests that blood pressure variability during the perioperative period may increase the risk of cerebral hyperperfusion syndrome.

Carotid Artery Stenting for Patients with Radiation-Induced Carotid Artery Stenosis

Objective

In radiation-induced carotid artery stenosis (RIS), morphological characteristics, such as bilateral and long lesion distances and in-stent stenosis, have been reported as common after carotid artery stenting (CAS). Here, we present 25 cases at our hospital wherein CAS was performed for RIS and compare the morphological characteristics and the safety of the treatment with cases of atherosclerotic carotid artery stenosis (AS).

Methods

Twenty-five lesions from 21 patients underwent CAS for RIS at our hospital between March 2002 and July 2020. The procedure was performed at a mean of 10.0 ± 5.2 years after radiation therapy with 60-72 Gy, with a median follow-up of 45 months. We retrospectively selected consecutive patients with AS with comparable follow-up times from the beginning of the study as controls. We compared the patients' background, stenosis findings including plaque MRI, perioperative period, and postoperative course.

Results

All patients in both groups completed the procedure, and the median follow-up time for the RIS and AS groups was 45 and 40 months, respectively (p = 0.1479). Patients in the RIS group had a lower mean age (69.9 ± 6.9 vs. 75.3 ± 7.04, p = 0.0075), a higher stenosis rate (79.1 ± 8.7% vs. 68.6 ± 11.7%, p = 0.0032), and longer stenosis greater than one vertebra (long lesions) (10 vs. 1, p = 0.0046) compared with the patients in the AS group. Although there was no significant difference in outcomes between the two groups, restenosis tended to be more common in the RIS group. Plaque MRI was characterized by a significantly higher T2WI signal (p = 0.0381) in the RIS group, which was attributable to the fact that a necrotic core has been reported commonly in the plaque tissue of RIS.

Conclusion

RIS has a high likelihood of restenosis both morphologically and in terms of plaque characteristics. Thus, close follow-up is crucial.

Flat Detector CT with Cerebral Pooled Blood Volume Perfusion in the Angiography Suite: From Diagnostics to Treatment Monitoring

C-arm flat-panel detector computed tomographic (CT) imaging in the angiography suite increasingly plays an important part during interventional neuroradiological procedures. In addition to conventional angiographic imaging of blood vessels, flat detector CT (FD CT) imaging allows simultaneous 3D visualization of parenchymal and vascular structures of the brain. Next to imaging of anatomical structures, it is also possible to perform FD CT perfusion imaging of the brain by means of cerebral blood volume (CBV) or pooled blood volume (PBV) mapping during steady state contrast administration. This enables more adequate decision making during interventional neuroradiological procedures, based on real-time insights into brain perfusion on the spot, obviating time consuming and often difficult transportation of the (anesthetized) patient to conventional cross-sectional imaging modalities. In this paper we review the literature about the nature of FD CT PBV mapping in patients and demonstrate its current use for diagnosis and treatment monitoring in interventional neuroradiology.

Perioperative functional imaging after extracranial carotid endarterectomy for the detection of cerebral hyperperfusion syndrome

INTRODUCTION

SyngoDynaPBVNeuro® is a tool to perform cerebral blood volume (CBV) measurements intraoperatively by functional imaging producing CT-like images. Aim of this prospective study was to analyze the clinical relevance and benefit of CBV measurement with regard to neurological complications like cerebral hyperfusion syndrome (CHS).

METHODS

Forty-five patients undergoing endarterectomy (CEA) of the internal carotid artery were included; functional imaging with CBV measurement was performed before and after CEA. To evaluate and analyze CBV, six regions of interest (ROI) were identified for all patients with an additional ROI in patients with symptomatic ICA stenosis and previous stroke. The primary endpoint of the study was a perioperative change in CBV measurements. Secondary outcomes were incidence of stroke, TIA, CHS, and perioperative morbidity and mortality.

RESULTS

Thirty-day stroke incidence and thirty-day mortality were 0%. Thirty-day morbidity was 6.7%. Two patients from the asymptomatic group suffered from transient neurological symptoms without signs of intracerebral infarction in CT or MR scan, meeting diagnostic criteria for CHS. In 83.3% of ROIs in these patients, an increase of blood volume was detected. Overall, 26.7% patients suffered from unilateral headache as expression of potential CHS. A total of 69.4% of ROIs in patients with postoperative unilateral headache showed an increase when comparing pre- and postoperative CBV measurements.

CONCLUSION

The results show that increased CBV measured by functional imaging is a possible surrogate marker of neurological complications like CHS after CEA. By using intraoperative CBV measurement, the risk of CHS can be estimated early and appropriate therapeutic measures can be applied.

Retrospective multicenter study on the management of asymptomatic carotid artery stenosis with coexistent unruptured intracerebral aneurysm

AIM OF THE STUDY

To evaluate the results of carotid endarterectomy (CEA) in patients with a concomitant asymptomatic intracranial aneurysm discovered at preoperative diagnostic imaging.

MATERIAL AND METHODS

From January 2000 to December 2020, 75 consecutive patients admitted for surgical treatment of asymptomatic >70% (NASCET) carotid artery stenosis presented at preoperative computed tomography angiography (CTA) with a concomitant, unruptured intracranial aneurysm (UIA). Aneurysm diameter was ≤ 5 mm in 25 patients (Group A), from 6 to 9 mm in 38 patients (Group B) and ≥ 10 mm in 12 patients (Group C). Sixty UIAs (80%) were treated before performing CEA, 10 in Group A (40%), 38 (100%) in Group B and 12 (100%) in Group C. Twenty-five UIAs (42%) were subjected to surgical clipping and 35 (58%) to coiling. The mean time intervals were 48 days (range, 20-55 days) between clipping and CEA, and 8 days (range, 4 -13 days) between coiling and CEA. Carotid endarterectomy (CEA) was standard and performed through eversion of the internal carotid artery (ICA) in 36 patients (48%) and through longitudinal arteriotomy with systematic patch closure in 39 patients (52%). Primary endpoints of the study were mortality and morbidity related to each of the two treatments including any complication occurring during the time interval between the two procedures or within 30 days after the last procedure. Secondary endpoints were mid-term survival and freedom from ischemic or hemorrhagic stroke and carotid restenosis.

RESULTS

One patient died during the 30 days following clipping of a 11 mm diameter UIA of the basilar artery. No other death or complication was observed following CEA and treatment of the UIA, or during the time interval between the two procedures. During median follow-up of 26 months (IQR, 18-30 months), no late stroke and no carotid restenosis were observed. At 22, 27, 29 and 31 months after CEA, four patients in group A underwent surgical clipping of an enlarging intracranial aneurysm, which had not been treated initially due to its small diameter. Cumulative survival rate at 30 months by Kaplan-Meier plots was 83±5%.

CONCLUSIONS

Concomitant asymptomatic carotid artery stenosis and UIA is a rare entity. Our study suggests that in this setting, prior treatment of the UIA followed by CEA is safe.

Charles Bonnet Syndrome in a Patient With Acute Glaucoma Following Carotid Endarterectomy

Acute neovascular glaucoma is an extremely rare complication following carotid artery revascularization that can lead to permanent vision loss. We describe an unusual case of acute glaucoma following carotid endarterectomy presenting with mechanical pupillary dilation and vivid visual hallucinations consistent with the Charles Bonnet Syndrome. This case highlights the importance of screening patients complaining of vision loss or eye pain for neovascular eye changes prior to carotid revascularization. These patients' eye health should be closely monitored peri-operatively.

Relationship between cerebral hyperperfusion syndrome and the immediate change of cerebral blood flow after carotid artery stenting evaluated by single-photon emission computed tomography

PURPOSE

Cerebral hyperperfusion syndrome (CHS) is a critical complication after carotid artery stenting (CAS). However, few CAS studies have evaluated immediate and temporary changes in ipsilateral cerebral blood flow (CBF) quantitatively. The study was performed to evaluate immediate changes in CBF after CAS and subsequent CBF changes in patients with cerebral hyperperfusion (HP) using ¹²³I-IMP SPECT.

METHODS

The subjects were 223 patients with chronic extracranial carotid artery stenosis who underwent CAS in our department between March 2010 and March 2020. Quantitative CBF and cerebrovascular reactivity to acetazolamide in the middle cerebral artery were assessed before CAS by ¹²³I-IMP SPECT. CBF was also measured immediately after CAS by ¹²³I-IMP SPECT. When HP was detected, CBF was measured again 3 and 7 days after CAS.

RESULTS

The median (interquartile range) ipsilateral quantitative CBF change after CAS was - 0.1% (- 9.5-8.2%), and the upper value of the 95% CI of the quantitative CBF change was 48.2%. Thus, we defined HP after CAS as an increase in quantitative CBF of > 48.2% compared with the preoperative value. Of 223 patients, 5 (2.2%) had HP, and 4 of these patients (80%) developed CHS. In the CHS patients, HP was maintained for about 3 days and improved after about 7 days.

CONCLUSION

An immediate CBF increase of > 48.2% after CAS may lead to development of CHS. In CHS after CAS, HP persisted for about 1 week and postoperative management may be required for at least 1 week.

Association between carotid revascularization for asymptomatic stenosis and cognitive functions

Summary: Asymptomatic carotid stenosis (ACS) can cause cognitive dysfunction, related to cerebral hypoperfusion and microemboli. These mechanisms could be treated by carotid revascularization, but the impact of carotid angioplasty stenting (CAS) or carotid endarterectomy (CEA) on cognitive functions remains unclear. The aim of this systematic review was to realize a report on the actual state of results about asymptomatic carotid stenosis revascularization and cognitive function. We performed a systematic literature review to analyze all studies assessing the impact of asymptomatic carotid stenosis revascularizations on cognitive functions. We reviewed all publications published in Medline database and Cochrane between January 2010 and January 2020 including subjects with a cognitive evaluation and receiving carotid revascularization for asymptomatic stenosis. We identified 567 records for review, and finally we included in the systematic review 20 studies about ACS revascularization and cognitive functions. Only observational studies analyzed the impact of CEA and CAS on cognitive functions. Thus, too heterogeneous data associated to the lack of randomized controlled trials with an evaluation of optimal medical treatment did not enable to affirm the interest of the revascularization management of ACS in cognitive domain. There was a lack of standardization and finally studies were too heterogeneous to conclude on the impact of carotid revascularization on cognitive functions. There is an urgent need to harmonize research in this domain in order to prevent and treat cognitive dysfunction related to ACS, especially in our society with an aging population.

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.

A bibliometric analysis on the most-cited publications on carotid endarterectomy throughout history

Objective

Carotid endarterectomy (CEA) is the gold standard surgical procedure for managing carotid stenosis due to atherosclerosis and reducing the risk of ischemic stroke. This bibliometric analysis summarizes the most-cited articles on CEA and highlights the contributing articles to today’s evidence-based practice.

Methods

A title-specific search using the Scopus database was used to perform the search. Pertinent article-based, journal-based, and author-based parameters were obtained for review.

Results

A total of 6,824 articles were published between 1970 and 2020. The top 100 most-cited articles accumulated a total of 54,153 citations with an average citation count (CC) of 541, with only a 4.53% self-citation rate for all authors. The publication trends peaked between 1997 and 2010, in which two-third of the highly cited works were published. The most prolific categories with top citations are the clinical, indications, and management, in a descending order. There were 41 published Randomized Controlled Trials (RCT) in the most-cited list.

Conclusions

Citation analysis on carotid endarterectomy has witnessed a marked shift in the publication trends from studying the outcome and complications to comparing carotid stenting with endarterectomy. This analysis is a good introductory article to physicians interested in this topic, as it summarizes the highly impactful articles and enlists the most-cited RCT on CEA.

Reduced magnetic resonance angiography signal intensity in the middle cerebral artery ipsilateral to severe carotid stenosis may be a practical index of high oxygen extraction fraction

Objectives

Angiographic “slow flow” in the middle cerebral artery (MCA), caused by carotid stenosis, may be associated with high oxygen extraction fraction (OEF). If the MCA slow flow is associated with a reduced relative signal intensity (rSI) of the MCA on MR angiography, the reduced rSI may be associated with a high OEF. We investigated whether the MCA slow flow ipsilateral to carotid stenosis was associated with a high OEF and aimed to create a practical index to estimate the high OEF.

Methods

We included patients who underwent digital subtraction angiography (DSA) and MRA between 2015 and 2019 to evaluate carotid stenosis. MCA slow flow by image count using DSA, MCA rSI, minimal luminal diameter (MLD) of the carotid artery, carotid artery stenosis rate (CASr), and whole-brain OEF (wb-OEF) was evaluated. When MCA slow flow was associated with a high wb-OEF, the determinants of MCA slow flow were identified, and their association with high wb-OEF was evaluated.

Results

One hundred and twenty-seven patients met our inclusion criteria. Angiographic MCA slow flow was associated with high wb-OEF. We identified MCA rSI and MLD as determinants of angiographic MCA slow flow. The upper limits of MCA rSI and MLD for angiographic MCA slow flow were 0.89 and 1.06 mm, respectively. The wb-OEF was higher in patients with an MCA rSI ≤ 0.89 and ipsilateral MLD ≤ 1.06 mm than patients without this combination.

Conclusions

The combination of reduced MCA rSI and ipsilateral narrow MLD is a straightforward index of high wb-OEF.

Key Points

• The whole-brain OEF in patients with angiographic slow flow in the MCA ipsilateral to high-grade carotid stenosis was higher than in patients without it.

• Independent determinants of MCA slow flow were MCA relative signal intensity (rSI) on MRA or minimal luminal diameter (MLD) of the carotid stenosis.

• The wb-OEF was higher in patients with an MCA rSI ≤ 0.89 and ipsilateral MLD ≤ 1.06 mm than patients without this combination.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08272-3.

Development of cerebral microbleeds in patients with cerebral hyperperfusion following carotid endarterectomy and its relation to postoperative cognitive decline

OBJECTIVE

A primary cause of cognitive decline after carotid endarterectomy (CEA) is cerebral injury due to cerebral hyperperfusion. However, the mechanisms of how cerebral hyperperfusion induces cerebral cortex and white matter injury are not known. The presence of cerebral microbleeds (CMBs) on susceptibility-weighted imaging (SWI) is independently associated with a decline in global cognitive function. The purpose of this prospective observational study was to determine whether cerebral hyperperfusion following CEA leads to the development of CMBs and if postoperative cognitive decline is related to these developed CMBs.

METHODS

During the 27-month study period, patients who underwent CEA for ipsilateral internal carotid artery stenosis (≥ 70%) also underwent SWI and neuropsychological testing before and 2 months after surgery, as well as quantitative brain perfusion SPECT prior to and immediately after surgery.

RESULTS

According to quantitative brain perfusion SPECT and SWI before and after surgery, 12 (16%) and 7 (9%) of 75 patients exhibited postoperative cerebral hyperperfusion and increased CMBs in the cerebral hemisphere ipsilateral to surgery, respectively. Cerebral hyperperfusion was associated with an increase in CMBs after surgery (logistic regression analysis, 95% CI 5.08-31.25, p < 0.0001). According to neuropsychological assessments before and after surgery, 10 patients (13%) showed postoperative cognitive decline. Increased CMBs were associated with cognitive decline after surgery (logistic regression analysis, 95% CI 6.80-66.67, p < 0.0001). Among the patients with cerebral hyperperfusion after surgery, the incidence of postoperative cognitive decline was higher in those with increased CMBs (100%) than in those without (20%; p = 0.0101).

CONCLUSIONS

Cerebral hyperperfusion following CEA leads to the development of CMBs, and postoperative cognitive decline is related to these developed CMBs.

Hypocapnia Induced by Hyperventilation with Indocyanine Green Kinetics Detects the Effect of Staged Carotid Angioplasty to Avoid Hyperperfusion in Patients with Impaired Cerebral Hemodynamic Reserve

Cerebral hyperperfusion syndrome (CHS) is a serious complication following carotid artery stenting (CAS). Staged angioplasty (AP) could potentially prevent CHS and hyperperfusion phenomenon (HPP) after revascularization. However, methods for measuring the effects of staged AP on cerebral hemodynamic reserve have not been established. Here, we evaluated whether indocyanine green kinetics and near-infrared spectroscopy (ICG-NIRS) with hypocapnia induced by hyperventilation can detect the effects of staged AP on hemodynamic reserve to prevent CHS after CAS. Participants comprised 44 patients at high risk of CHS, whose ipsilateral cerebrovascular reactivity (CVR) was impaired on preoperative single photon emission computed tomography (SPECT). Patients were divided into a staged AP group (n=13) and a regular CAS group (n=31). In the staged AP group, stenting was performed 3 weeks after staged AP. In the regular CAS group, 16 cases (52%) showed HPP, and five (16%) presented with CHS after CAS, while no HPP or CHS occurred in the staged AP group (p=0.001). Changes in blood flow index (BFI) and time to peak (TTP) ratio during hypocapnia calculated from ICG-NIRS indicated a significant linear relationship with preprocedural CVR on SPECT (r=-0.710, 0.632, respectively; p<0.0001 each). BFI and TTP ratios during hypocapnia were significantly improved after staged AP (p<0.001 each). Furthermore, significant linear correlations were observed between BFI and TTP ratio during hypocapnia and postoperative asymmetry index AI (r=0.405, -0.475, respectively; p<0.01 each). Hypocapnia induced by hyperventilation under ICG-NIRS appears useful for detecting the effects of staged AP on hemodynamic reserve in patients at high risk of CHS.

Massive non-aneurysmal subarachnoid hemorrhage after cervical carotid angioplasty and stenting: a case report and review of the literature

INTRODUCTION

Carotid angioplasty and stenting (CAS) of the cervical segment is a safe and effective procedure for the treatment of carotid artery disease. In rare cases, this procedure causes intracranial hemorrhage (ICH), which is described most often as an ipsilateral intra-parenchymal hematoma. This ICH is the result of a cerebral hyperperfusion syndrome (CHS). Isolated subarachnoid hemorrhage may occur exceptionally, with only 9 cases that have been reported in the literature.

OBSERVATION

We reported a case of a 71-year-old man who presented a massive non-aneurysmal subarachnoid hemorrhage one hour after angioplasty and stenting of the cervical segment of the left internal carotid artery. Medical and surgical management included external ventricular drain placement. Rebleeding occurred two days later, worsening the patient's clinical condition. Finally, the patient died 2 weeks later.

COMMENTS

This rare presentation of ICH following CAS allows us to discuss the risk factors, complications and management of CHS.

New-onset lesions on MRI-DWI and cerebral blood flow changes on 3D-pCASL after carotid artery stenting

This study aimed to investigate the relationship between the new-onset hyperintense lesions on diffusion-weighted images (DWI) and the changes of cerebral blood flow (CBF) before and after carotid artery stenting (CAS) in patients with symptomatic unilateral carotid artery stenosis. Twenty-four patients with symptomatic unilateral carotid stenosis (50-99%) were enrolled. Routine head magnetic resonance imaging and three-dimensional pseudo-continuous arterial spin labeling were taken 7 days before the surgery and for four consecutive days post CAS. While the incidence of new DWI lesions were high (17/24, 70.8%) and 176 lesions were observed among the 17 cases, there was only one subject showing the symptoms. The majority of the lesions were located at the cortex/subcortex of the ipsilateral frontal and parietal lobes (60.8%) with 92.6% of the lesions size being less than 3 mm. The CBFs in this area were significantly higher than that of the temporal lobe on the first 3 days post stenting (p < 0.05). No periprocedural CBF differences were observed between the two groups, however, the micro-embolism group presented decreased relative CBF in frontal and parietal lobes prior to stenting compared with the non-embolism group. The systolic blood pressure in the micro-embolism group at discharge was significantly lower than that at admission. The high incidence rate of micro-embolism in patients receiving CAS may not be the result of direct changes of hemodynamics in the brain but rather the loss of CBF regulation due to long-term hypoperfusion prior to the stenting.

Imaging Identification and Prognosis of the Distal Internal Carotid Artery With Near and Complete Occlusion After Recanalization

Background and Purpose: Previous studies have mainly focused on treatment strategies and clinical outcomes for internal carotid artery near occlusion (ICANO) and internal carotid artery complete occlusion (ICACO). However, reports on the morphological changes of distal internal carotid artery (ICA) after recanalization are scarce. This study aimed at illustrating identifying features, assessing prognosis of the distal ICA after recanalization, and exploring best practices for treatment for ICANO and ICACO.

Materials and Methods: We retrospectively studied the clinical characteristics of 57 patients with ICANO or ICACO who underwent surgical recanalization. The clinical data, angiographic morphology, technical successful rate, perioperative complications, and the lumen changes of distal ICA before and after successful recanalization were analyzed.

Results: Fifty-two patients who achieved successfully recanalization were studied. Based on the postoperative lumen diameter changes in the distal ICA, 19 cases were classified as distal-dilatation and the remaining 33 as distal-narrowness. Patients in the distal-narrowness group mostly had ICACO (21.1 vs. 54.5%) and were men (68.4 vs. 93.9%). In the distal-narrowness group, the lumen of the distal ICA recovered to normal in 32 of the 33 patients during the follow-up period. Of the 32 patients reviewed, the ICA of 28 patients dilated back to normal after 1 week of surgery; the ICA of remaining patients 4 dilated 2 weeks postoperatively.

Conclusions: Narrowness of the distal ICA after hybrid recanalization was more prevalent in male patients with ICACO. Homogeneous stenosis of the whole course of the distal ICA is a low-perfusion narrowness which does not require intervention and will spontaneously recover after successful recanalization with an increase in the forward flow.

Usefulness of 2D-Perfusion Analysis for the Assessment of Unilateral Cervical Internal Carotid Artery Stenosis

Objective

We investigated the usefulness of 2D-perfusion analysis for the evaluation of cerebral blood flow in unilateral cervical internal carotid artery stenosis.

Methods

We conducted a 2D-perfusion analysis during cerebral angiography and ¹²³I-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) for unilateral cervical internal carotid artery stenosis without contralateral stenosis. The relationship between the ratio of the lesion side to the normal side in the parameters obtained by 2D-perfusion and the value calculated by stereotactic extraction estimation (SEE) analysis of SPECT was statistically examined.

Results

The ratios of the lesion side to the normal side regarding the peak arrival time (AT; time to peak [TTP]) of the contrast agent and the mean filling time (mean transit time [MTT]) of the contrast agent in 2D-perfusion significantly correlated with the area of Stage II and increase ratio (I.R) ≤30% in the SEE analysis (p = 0.002, 0.003).

Conclusion

2D-perfusion analysis can be used to estimate the extent of impaired cerebrovascular reserve (CVR) area in unilateral internal carotid artery stenosis.

Suspected Cerebral Hyperperfusion Syndrome after Stenting for Intracranial Vertebral Artery Stenosis Associated with Reduced Cerebral Blood Flow to the Posterior Cerebral Artery Territory

Objective

Although several studies have reported on cerebral hyperperfusion syndrome (CHS)/hyperperfusion phenomenon (HPP) involving the anterior circulation after carotid artery stenting (CAS), little is known about CHS/HPP involving the posterior circulation after percutaneous transluminal angioplasty (PTA) and stenting of the vertebral artery (VA).

Case Presentation

A 79-year-old man with known chronic occlusion of the left VA (V4 segment) was admitted to another hospital with right-sided hemiplegia, mild disturbance of consciousness, and dysphagia. A head MRI revealed multiple infarcts in posterior circulation areas, and severe stenosis of the right VA (V4 segment). Single photon emission computed tomography (SPECT) indicated reduced cerebral blood flow (CBF) in the posterior circulation, and DSA revealed 76% stenosis of the right V4 segment. On day 18, PTA/stenting was performed under general anesthesia for the severe stenosis of the right VA. However, head MRI and CT on postoperative day (POD)1 showed intracranial hemorrhage (ICH) occupying an area measuring 2 cm in diameter in the left posterior lobe and a small subdural hematoma (SDH). SPECT on POD1 indicated increased CBF in the posterior lobe, and we diagnosed CHS might have caused ICH. Although SPECT on POD4 showed residual hyperperfusion, SPECT on POD11 revealed reduced CBF in the posterior circulation area.

Conclusion

Our patient developed ICH after undergoing PTA/stenting for known severe symptomatic stenosis of the right VA. CHS/HPP in the posterior cerebral artery territory might be one of the etiologies, and reduced CBF prior to the procedure could be a risk factor for CHS/HPP developing after PTA/stenting.

Near-Infrared Spectroscopy Might Help Prevent Onset of Cerebral Hyperperfusion Syndrome

Cerebral hyperperfusion syndrome (CHS) is a rare but fatal perioperative complication after surgical correction of carotid stenosis. Despite numerous treatment options for preventing CHS, it does occur in some patients. We developed the outlet gate technique (OGT), in which the embolic balloon was deflated gradually in accordance with the ratio of oxygen saturation measured by a brain oximeter of the ipsilateral brain region to that in the contralateral region. Between June 2017 and May 2018, 39 patients with carotid stenosis underwent endovascular carotid revascularization procedures; of these, 20 underwent the procedure with the OGT. CBO was measured five times in those 20 patients: before the procedure, with the embolic protection device (EPD) on, with the EPD off, during the procedure, and after the procedure. Preventive treatment options were used more frequently in these patients, and although their surgical status seemed more complicated, perioperative complications were not increased. There were almost significant differences between CBO values except between those during and after the procedure with the OGT. This showed that the OGT allowed for stabilization of the CBO and thus has the potential to prevent CHS.

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.

Perioperative Blood Pressure Control in Carotid Artery Stenosis Patients With Carotid Angioplasty Stenting: A Retrospective Analysis of 173 Cases

Background: Carotid angioplasty stenting (CAS) is a currently widely used surgical treatment of carotid artery stenosis. However, the influences of the perioperative blood pressure (BP) on patients' prognosis remain unclear.

Objective: The present study was designed to explore the effects of different perioperative BP control strategies on CAS patients' prognosis.

Methods: One hundred seventy-three consecutive patients admitted between January 2016 and April 2019 were reviewed retrospectively. The outcomes of patients with different systolic BP (<120, 120–130, and >130 mmHg) before CAS and within 24 h after CAS were compared. The primary outcomes were the incidence of secondary cerebral infarction (CI) and intracranial hemorrhage (ICH) after CAS. The secondary outcome was the incidence of unfavorable discharge and in-hospital death. The unfavorable discharge was defined as modified Rankin Scale (mRS) score 3–5 at discharge.

Results: There was no significant difference between the incidences of ICH (P = 0.803) and CI (P = 0.410) in patients with different BP before CAS. The patients with post-CAS BP values of >130 mmHg had a 37.67-fold increased risk (95% CI: 6.79–209.01) of ICH compared with others, while no significant difference was observed on the incidence of CI (P = 0.174) among patients with different post-CAS BP values. The patients with post-CAS BP values of >130 mmHg also had a significantly higher incidence of unfavorable discharge (P = 0.002) and in-hospital death (P = 0.001) compared with others.

Conclusion: High BP (>130 mmHg) within 24 h after CAS significantly increases the risks of secondary cerebral hemorrhage, unfavorable discharge, and in-hospital death. Thus, the BP should be controlled below 130 mmHg in the first 24 h after CAS.

A Case of Cerebral Hyperperfusion Showing Unique Characteristics on Susceptibility-weighted MR Imaging after Carotid Endarterectomy

Cerebral hyperperfusion syndrome (CHS) is a potentially devastating complication of carotid endarterectomy (CEA). Early detection and treatment of hyperperfusion are important before the condition develops into CHS. We herein present a case involving a 65-year-old female with severe right internal carotid artery (ICA) stenosis, who experienced hyperperfusion after right CEA. During the postoperative course, changes in the resting cerebral blood flow (rCBF) were evaluated using single-photon emission computed tomography (SPECT), and were found to correlate with the changes in the signal intensity of cortical arteries, cortical veins, and perilateral ventricular veins of the right middle cerebral artery (MCA) territory on susceptibility-weighted imaging (SWI). SWI showed a prominent hyperintensity of cortical arteries in the right MCA territory at postoperative day 1 (POD1), but the hyperintensity gradually decreased over time and became indistinct by POD48. As for cortical veins and perilateral ventricular veins, SWI showed an increased signal intensity of these veins during the peak of rCBF on POD1, but later, the signal intensity decreased as rCBF decreased on POD5. The signal intensity of cortical veins and perilateral ventricular veins finally returned to normal on POD9. Those SWI findings could be related to an impairment of cerebral autoregulation and the resulting hyperperfusion. SWI could be potentially useful as an additional tool in the evaluation of hyperperfusion.

Utility of Near-infrared Spectroscopy Monitoring in the Management of Hyperperfusion Syndrome after Intracranial Carotid Artery Stenting

Cerebral hyperperfusion syndrome (HPS) is a rare complication of carotid endarterectomy (CEA) and stenting. There are only a few case reports about HPS after intracranial stenting, and its clinical course remains unclear. We report an unusual case of HPS after intracranial internal carotid artery (ICA) stenting. An 87-year-old woman underwent uneventful balloon angioplasty for the right intracranial ICA one year ago; then she presented with restenosis at the same arterial location. She then underwent an ICA stent placement procedure. Preoperative cerebral blood flow (CBF) studies revealed hemodynamic ischemia. At the time of surgery, the stenotic lesion was near-occlusion. Twelve hours after the successful stenting procedure, the patient became restless, and near-infrared spectroscopy (NIRS) indicated a blood flow increase to the affected side. Arterial spin labeling (ASL) imaging performed on the same day showed high signal intensity only in the right hemisphere. She was treated with sedation, blood pressure control, and minocycline hydrochloride administration. Because of the strict management under continuous monitoring with NIRS, her symptoms gradually improved over the next 6 days. The right-to-left difference observed with ASL imaging resolved 6 days after surgery, and she was discharged with no neurological deficit. This case highlights the utility of NIRS monitoring in the management of HPS after intracranial stenting.

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.

Concomitant Reversible Cerebral Vasoconstriction and Hyperperfusion Syndromes Following Carotid Endarterectomy

Cerebral hyperperfusion syndrome (CHS) and reversible cerebral vasoconstriction syndrome (RCVS) are two syndromes characterized by disordered vascular autoregulatory mechanisms of brain. These may be seen after carotid endarterectomy (CEA). We present a patient who developed both syndromes after CEA which is a rare occurrence.

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.

Prediction of the Cerebral Hyperperfusion Phenomenon after Carotid Endarterectomy Using a Transit Time Flowmeter

The purpose of this study was to investigate the relationship between the cerebral hyperperfusion phenomenon (CHP) and carotid artery flow volume as measured by a transit time flowmeter during carotid endarterectomy (CEA). We retrospectively investigated 74 patients who underwent both transit time flowmetry and single photon emission computed tomography (SPECT). The flow volumes of the internal carotid artery (ICA) before and after the endarterectomy were recorded during surgery as the pre- and the post-ICA (mL/min), respectively. We defined the difference between the pre- and the post-ICA as the ΔIC (mL/min). Two independent board-certified neurosurgeons analyzed the asymmetry index (affected side/contralateral side) of regional qualitative cerebral blood flow before and after the CEA respectively. We defined the CHP as an excessive increase in this asymmetry index between preoperative and postoperative SPECT. The CHP was observed in five of the 74 patients (6.8%). The pre-ICA of the CHP cases was significantly lower than that of the non-CHP cases (in mL/min, median 29 vs. 97; P = 0.01). The ΔIC of the CHP cases was significantly higher than that of the non-CHP cases (in mL/min, median 154 vs. 50; P = 0.002). The cut-off value of the ΔIC was 81 mL/min (sensitivity 100%, specificity 78.3%, area under the curve 0.912). The findings of this study suggest that the ΔIC is associated with the CHP. The transit time flowmeter is useful to predict the CHP during surgery.