Cerebral hyperperfusion syndrome after percutaneous transluminal stenting of the craniocervical arteries

Carotid artery stenting and endarterectomy surgery techniques: A 30‑year time‑lapse

Carotid endarterectomy or carotid artery stenting (CAS), are the most important axes in carotid artery interventional management. A bibliometric analysis permits an easier access to the current literature trends and information to design future studies. The aim of the present study was to identify the knowledge routes on CAS and examine the research front on the topic. The search was interpreted in Scopus, from 1994 to 2023, and included only original articles and reviews. The BibTex format was used to download all citation and bibliographic data. The present analysis was conducted in two parts, a descriptive one and a network extraction process. Between 1994 and 2023, 34,503 references and 7,758 authors were recorded. The annual growth rate was 21.64%. The CAVATAS trial was the most cited article. As regards word trends, since 2017, trans-carotid stenting, risk factors and plaque characteristics are highlighted. CAS remains an area of high interest with a publication growth rate of >20% per year. As numerous questions remain to be answered, the need to determine the role of CAS may drive further research.

Pictorial Review on Imaging Findings in Cerebral CTP in Patients with Acute Stroke and Its Mimics: A Primer for General Radiologists

The imaging evaluation of computed tomography (CT), CT angiography (CTA), and CT perfusion (CTP) is of crucial importance in the setting of each emergency department for suspected cerebrovascular impairment. A fast and clear assignment of characteristic imaging findings of acute stroke and its differential diagnoses is essential for every radiologist. Different entities can mimic clinical signs of an acute stroke, thus the knowledge and fast identification of stroke mimics is important. A fast and clear assignment is necessary for a correct diagnosis and a rapid initiation of appropriate therapy. This pictorial review describes the most common imaging findings in CTP with clinical signs for acute stroke or other acute neurological disorders. The knowledge of these pictograms is therefore essential and should also be addressed in training and further education of radiologists.

Bibliometric and visual analysis of cerebral revascularization from 1999 to 2022

Background

Cerebral revascularization is a neurosurgical procedure used to restore the cerebral collateral circulation channel. This study examines the countries, institutions, authors, journals, keywords, and references related to the disease in the field of cerebral revascularization from 1999 to 2022 from a bibliometrics perspective, evaluates the changes of knowledge structure clustering and identifies the new hot spots and new research directions in this field.

Methods

The Web of Science Core Collection (WOSCC) database and the PICOS retrieval method were used to conduct a comprehensive search for articles and reviews pertaining to cerebral revascularization. The final filtered data were bibliometrically and visually drawn using Microsoft office 365, CiteSpace (v.6.1.R2), and VOSviewer (v.1.6.18).

Results

From 1999 to 2022, a total of 854 articles pertaining to cerebral revascularization, which originated from 46 nations, 482 institutions, and 686 researchers, were extracted from the WOSCC database, and the number of publications in this field of study was rising. The United States held the highest proportion in the ranking analysis of countries, institutions, authors, and journals. By analyzing co-citations, the scientific organization of this field and the development status of frontier fields were realized. Cerebral revascularization, moyamoya disease, extracranial intracranial bypass, and occlusion are the current research focal points in the field of cerebral revascularization. Hyperperfusion and vascular disorder may also become a new study focus in this discipline in the near future.

Conclusion

Using the method of bibliometrics, this study analyzed and reviewed the articles in the field of cerebral revascularization, which enabled scholars to better comprehend the dynamic process in this field and provided a foundation for future in-depth research.

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.

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.

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.

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.

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.

Endovascular Recanalization of Nonacute Symptomatic Vertebral Ostial Occlusion Performed Using a Distal Embolic Protection Device

OBJECTIVE

Endovascular recanalization of symptomatic vertebral ostial occlusion in the nonacute phase has not been well documented. Distal thromboembolic events negatively affect the success of endovascular treatment. We aimed to investigate the feasibility, safety, and outcomes of stenting performed with the use of a distal embolic protection device for patients with symptomatic vertebral ostial occlusion in the nonacute phase.

METHODS

We retrospectively reviewed the data of 7 patients with symptomatic vertebral ostial occlusion despite medical management who underwent stenting performed using a distal embolic protection device between January 2015 and February 2019. The occlusive lesions were predilated with small balloons, followed by placement of distal embolic protection devices and stents sequentially. At last, the protection devices were retrieved. The rate of successful recanalization, perioperative complications, and clinical and angiographic outcomes were analyzed.

RESULTS

The rate of successful recanalization was 100% with all distal embolic protection devices deployed and retrieved. Poststenting angiography showed no significant residual stenosis. There were no major acute thromboembolic events during and after the procedure. There were no recurrent ischemic symptoms after a mean clinical follow-up of 20.6 ± 16.3 months. At 6-month imaging follow-up, repeat vascular images from 5 patients showed asymptomatic restenosis in 1 artery.

CONCLUSIONS

Our single-center preliminary experience indicated that performing stent placement for vertebral ostial occlusion using a distal protection device may be feasible with a high rate of procedural success. However, this strategy should be confirmed in future prospective randomized studies with larger patient numbers.

Short-term Outcome of Straight vs Tapered Carotid Stenting for Symptomatic Carotid Artery Stenosis: A Prospective Study

PURPOSE

To investigate the short-term outcomes and complications of straight vs tapered carotid stent placement for patients with symptomatic carotid stenosis.

METHODS

A prospective study was conducted to examine if tapered carotid stents (TCS) performed better than straight carotid stents (SCS) in terms of complications and outcomes in patients with a unilateral, symptomatic, internal carotid artery stenosis ⩾70%. Between January 2014 and January 2016, 236 patients were screened; 88 were excluded, leaving 148 patients for 1:1 randomization to carotid artery stenting with either SCS or TCS. The data were analyzed for differences between the groups in terms of complications (hemodynamic depression, cerebral hyperperfusion syndrome, puncture site sequelae) and endpoint events (stroke, myocardial infarction, and death) at 30 days and 6 months.

RESULTS

Two patients in the TCS group underwent endarterectomy after allocation, leaving 72 patients (mean age 65.1±8.8 years; 59 men) in the TCS group for analysis vs 74 (mean age 65.0±7.9 years; 58 men) in the SCS group. The technical success was 100% in both groups. The incidence of hemodynamic depression (hypotension and bradycardia) after the procedures were higher in the SCS group (p=0.04), and the patients who underwent SCS procedures had longer hospital stays (p=0.01). There was no difference in the incidences of complications, myocardial infarction, mortality, or stroke at 30 days or 6 months between the SCS and TCS groups. The rates of restenosis (4% SCS vs 1% TCS) were similar (p=0.63); all restenoses were moderate (50%-70%).

CONCLUSION

When compared to straight stents, tapered carotid stents significantly decreased hemodynamic complications and hospital stay.

Staged carotid artery stenting in patients with severe carotid stenosis: Multicenter experience

Cerebral hyperperfusion syndrome (CHS) is serious complication after carotid artery stenting (CAS) caused by decreased cerebral vasoreactivity (CVR) due to long standing hypoperfusion of the brain. We hypothesized that partial dilatation of carotid stenosis would allow the recovery of CVR, and prevent CHS when definitive angioplasty with stent is performed afterward. In this study, we aimed to evaluate the safety and efficacy of staged CAS in patients with severe carotid artery stenosis with evident hemodynamic compromise in regard to preventing hyperperfusion syndrome. From January 2005 to February 2016, 53 patients with 55 severe carotid artery stenosis lesions showing decreased CVR and/or cerebral basal flow at the perfusion studies underwent staged CAS in three institutes. The procedure consisted of initial partial balloon angioplasty (BA), recovery period, and delayed definitive stenting (DS). We analyzed immediate results, complications, recoil and CHS related to staged CAS. We experienced no symptomatic manifestation of CHS except self-limited headache after the procedures. The median of intervals between BA and DS stages were 10 days. There was no case of severe recoil during the interval between BA and DS stage. Where perfusion imaging data was available, hyperperfusion was present in three and one patients after BA and DS stage, respectively, with no clinical symptom of CHS. In conclusion, staged CAS was feasible in patients with severe carotid artery stenosis and hemodynamic compromise, without inducing severe complication of CHS such as intracranial hemorrhage.

Cortical blindness as a rare presentation of hemorrhagic cerebral hyperperfusion syndrome following vertebral angioplasty

Cerebral hyperperfusion syndrome (CHS) is a well-documented complication after carotid endarterectomy or stenting. In contrast, CHS following vertebral revascularization is extremely rare. Here we present a case of a 77-year-old man with high-grade vertebral stenosis who subsequently underwent balloon angioplasty, complicated by hemorrhagic CHS manifesting as cortical blindness, although strict postoperative blood pressure control was administered. To our knowledge, cortical blindness as a presentation of hemorrhagic CHS has not previously been reported. This study highlights the fact that identifying high-risk patients, as well as making an individual therapeutic plan, is important prior to revascularization. Further studies are needed to elucidate the exact mechanism of this condition and thereby prevent it.

Objective evaluation of cerebrovascular reactivity for acetazolamide predicts cerebral hyperperfusion after carotid artery stenting: Comparison with region of interest methods

BACKGROUND AND PURPOSE

Hemodynamic impairments are considered risk factors of cerebral hyperperfusion after carotid artery stenting (CAS); measurement by Single-photon emission computed tomography (SPECT) using a subjective region of interest (ROI) method lacks consistency and reproducibility.

MATERIALS AND METHODS

The present study compared objective perfusion analysis (stereotactic extraction estimation [SEE] method) with the ROI method for preoperative SPECT to predict the hyperperfusion phenomenon (HPP) after CAS. Preoperative resting asymmetry index (cerebral blood flow [CBF] ratio from the affected to unaffected hemisphere) and cerebrovascular reactivity (CVR) to acetazolamide were measured by N-isopropyl-p-[¹²³I]-iodoamphetamine SPECT using the SEE and ROI method in 84 patients. CBF was also measured the day after CAS. Perfusion data with the highest area under the curve (AUC) by receiver-operating characteristic (ROC) analysis was considered a perfusion risk factor of HPP. Multivariate analyses for clinical characteristics and perfusion risk factors were performed to determine predictors of HPP.

RESULTS

The HPP was observed in 10 patients (11.9%). Female sex, contralateral stenosis, and degree of stenosis were significantly associated with HPP development on univariate analysis, and symptomatic stenosis was not found to be a significant factor. On SPECT analysis, CVR in the MCA area by SEE method had the highest AUC (0.981). Multivariate analysis showed that CVR in the MCA area was a significant predictor of HPP (P=0.041). To predict hyperperfusion, the ROC curve of the CVR showed a cutoff value of -0.60%, sensitivity of 94.6%, and specificity of 100% (P<0.001).

CONCLUSIONS

Objective SEE method had better a predictive capability than ROI method to identify risk of hyperperfusion after CAS.

Cortical blindness as a rare presentation of hemorrhagic cerebral hyperperfusion syndrome following vertebral angioplasty

Cerebral hyperperfusion syndrome (CHS) is a well-documented complication after carotid endarterectomy or stenting. In contrast, CHS following vertebral revascularization is extremely rare. Here we present a case of a 77-year-old man with high-grade vertebral stenosis who subsequently underwent balloon angioplasty, complicated by hemorrhagic CHS manifesting as cortical blindness, although strict postoperative blood pressure control was administered. To our knowledge, cortical blindness as a presentation of hemorrhagic CHS has not previously been reported. This study highlights the fact that identifying high-risk patients, as well as making an individual therapeutic plan, is important prior to revascularization. Further studies are needed to elucidate the exact mechanism of this condition and thereby prevent it.

Fluid-attenuated inversion recovery vascular hyperintensities in predicting cerebral hyperperfusion after intracranial arterial stenting

PURPOSE

No reliable imaging sign predicting cerebral hyperperfusion after intracranial arterial stenting (IAS) had been described in the literature. This study evaluated the effect of fluid-attenuated inversion recovery vascular hyperintensities (FVHs), also called hyperintense vessel sign on T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) MR images, in predicting significant increase in cerebral blood flow (CBF) defined by arterial spin labeling (ASL) after IAS.

METHODS

We reviewed ASL CBF images and T2-FLAIR MR images before (D0), 1 day after (D1), and 3 days after (D3) IAS of 16 patients. T1-weighted MR images were used as cerebral maps for calculating CBF. The changes in CBF values after IAS were calculated in and compared among stenting and nonstenting vascular territories. An increase more than 50% of CBF was considered as hyperperfusion. The effect of FVHs in predicting hyperperfusion was calculated.

RESULTS

The D1 CBF value was significantly higher than the D0 CBF value in stenting vascular, contralateral anterior cerebral artery, contralateral middle cerebral artery, and contralateral posterior cerebral artery (PCA) territories (all P < .05). The D1 and D3 CBF values were significantly higher than the D0 CBF value in overall vascular (P < .001), overall nonstenting vascular (P < .001), and ipsilateral PCA (P < .05) territories. The rate of more than 50% increases in CBF was significantly higher in patients who exhibited asymmetric FVHs than in those who did not exhibit these findings.

CONCLUSION

FVHs could be a critical predictor of a significant increase in CBF after IAS.

Uncommon Etiology for Seizure: Cerebral Hyperperfusion Syndrome

Cerebral hyperperfusion syndrome (CHS) is a rare life-threatening complication of carotid endarterectomy (CEA) and carotid artery stenting (CAS) for carotid artery stenosis. The incidence varies between 0 and 3%, depending on the severity of the stenosis, perioperative hypertension, and contralateral carotid stenosis. This case report reports a 53-year-old female patient presenting with decreased alertness and multiple tonic-clonic seizures, in the background of bilateral CEA. She was found to have bilateral carotid stenosis. Her left CEA was performed three months prior and right CEA was four days prior to her current presentation with seizures. After bilateral CEA, the imaging showed extensive pathologic process involving primarily the subcortical white matter and overlying cortex, more on the right cerebral hemisphere. On follow-up six weeks later, she reported no recurrent seizures and imaging showed decrease in abnormal signal intensity of the grey and white matter. This was indicative of near complete resolution of hyperperfusion damage. CHS is a rare complication due to the loss of autoregulation of the cerebrovascular system and increased blood flow status after bilateral CEA. This case is reported because of a rare and unique presentation of seizures in the background of bilateral CEA.

Neurologic complications of cardiac and vascular surgery

This chapter will provide an overview of the major neurologic complications of common cardiac and vascular surgeries, such as coronary artery bypass grafting and carotid endarterectomy. Neurologic complications after cardiac and vascular surgeries can cause significant morbidity and mortality, which can negate the beneficial effects of the intervention. Some of the complications to be discussed include ischemic and hemorrhagic stroke, seizures, delirium, cognitive dysfunction, cerebral hyperperfusion syndrome, cranial nerve injuries, and peripheral neuropathies. The severity of these complications can range from mild to lethal. The etiology of complications can include a variety of mechanisms, which can differ based on the type of cardiac or vascular surgery that is performed. Our knowledge about neuropathology, prevention, and management of surgical complications is growing and will be discussed in this chapter. It is imperative for clinicians to be familiar with these complications in order to narrow the differential diagnosis, start early management, anticipate the natural history, and improve outcomes.

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.

Angioplasty and stenting for patients with symptomatic intracranial atherosclerosis: study protocol of a randomised controlled trial

INTRODUCTION

Whether adding percutaneous transluminal angioplasty and stenting (PTAS) to background medical treatment is effective for decreasing the incidence of stroke or death in patients with symptomatic intracranial atherosclerosis (ICAS) is still controversial. We perform a randomised controlled trial to examine the effectiveness and safety of an improved PTAS procedure for patients with ICAS.

METHODS AND ANALYSIS

A randomised controlled trial will be conducted in three hospitals in China. Eligible patients with ICAS will be randomly assigned to receive medication treatment (MT) plus PTAS or MT alone. The MT will be initiated immediately after randomisation, while the PTAS will be performed when patients report relief of alarm symptoms defined as sudden weakness or numbness. All patients will be followed up at 30 days, 3 and 12 months after randomisation. The primary end point will be the incidence of stroke or death at 30 days after randomisation. Secondary outcomes will be the incidence of ischaemic stroke in the territory of stenosis arteries, the incidence of in-stent restenosis, the Chinese version of the modified Rankin Scale and the Chinese version of the Stroke-Specific Quality of Life (CSQoL).

ETHICS AND DISSEMINATION

The study protocol is approved by institutional review boards in participating hospitals (reference number FZ20160003, 180PLA20160101 and 476PLA2016007). The results of this study will be disseminated to patients, physicians and policymakers through publication in a peer-reviewed journal or presentations in conferences. It is anticipated that the results of this study will improve the quality of the current PTAS procedure and guide clinical decision-making for patients with ICAS.

TRIAL REGISTRATION NUMBER

NCT02689037.

Pathophysiology and management of reperfusion injury and hyperperfusion syndrome after carotid endarterectomy and carotid artery stenting

Cerebral hyperperfusion is a relatively rare syndrome with significant and potentially preventable clinical consequences. The pathophysiology of cerebral hyperperfusion syndrome (CHS) may involve dysregulation of the cerebral vascular system and hypertension, in the setting of increase in cerebral blood flow. The early recognition of CHS is important to prevent complications such as intracerebral hemorrhage. This review will focus on CHS following carotid endarterectomy and carotid artery stenting. We will discuss the typical clinical features of CHS, risk factors, pathophysiology, diagnostic modalities for detection, identification of patients at risk, and prevention and treatment. Although currently there are no specific guidelines for the management of CHS, identification of patients at risk for CHS and aggressive treatment of hypertension are recommended.

Hyperperfusion Syndrome of the Deltoid Muscle after Subclavian Artery Angioplasty and Stenting

Purpose:

To report a case of hyperperfusion syndrome of the deltoid muscle after percutaneous transluminal angioplasty of a symptomatic high-grade subclavian artery stenosis.

Case Report:

Immediately after balloon dilation of a left-sided subclavian artery stenosis, a 53-year-old man developed severe ipsilateral shoulder pain and swelling. Computed tomographic angiography revealed no extravasation or hematoma. Sonography showed massive edema and increased anteroposterior diameter of the left deltoid muscle (3.5 cm compared to 2.0 cm on the right). Hyperperfusion syndrome was suspected, and decompression by anterolateral fasciotomy was performed. Subsequently, both pain and swelling decreased. At day 3, the skin incision, which was temporarily covered with a synthetic skin substitute, was sutured; the wound healed uneventfully. Two weeks after surgery, both muscle strength and shoulder movements showed no restrictions.

Conclusions:

Hyperperfusion syndrome after endovascular treatment of subclavian artery stenosis should be considered in the differential diagnosis of atypical muscle pain in the upper extremity. It may present as a compartment syndrome requiring surgical decompression.

Intraoperative idiopathic subarachnoid hemorrhage during carotid artery stenting: A case report and literature review

Carotid artery stenting (CAS) has a fatal complication of intracranial hemorrhage (ICH) associated with cerebral hyperperfusion syndrome (CHS), i.e. brain hemorrhage and subarachnoid hemorrhage (SAH). Although SAH accounts for a small percentage of these patients, it is difficult to make a differential diagnosis of this syndrome from CHS without ICH because the clinical presentations resemble each other. Furthermore, not only does the cause of SAH following CAS remain unclear but also the role of controlling postoperative blood pressure is not detected in preventing ICH after CAS. Herein, we report a case of SAH following CAS and review previous literature to discuss the mechanism and the management of this fatal complication. A 78-year-old woman with a history of arteriosclerotic obliteration and myocardial infarction was referred to our department for intervention to asymptomatic severe stenosis of the right internal carotid artery. We performed CAS under local anesthesia. Although her blood pressure was controlled to normotension during the procedure, the patient complained of headache following predilation. Postoperative emergent non-contrast computed tomography revealed SAH with leakage of contrast medium occupying the right sylvian fissure. We continued strict blood pressure control, and the patient was discharged without any neurological deficit. A well-opened lumen of the stent was recognized three months later at the outpatient visit. Strict control of intraoperative and postoperative blood pressure may improve the outcome of SAH following CAS though the role in preventing ICH after CAS is unclear.

Clinical Presentation, Imaging, and Management of Complications due to Neurointerventional Procedures

Neurointervention is a rapidly evolving and complex field practiced by clinicians with backgrounds ranging from neurosurgery to radiology, neurology, cardiology, and vascular surgery. New devices, techniques, and clinical applications create exciting opportunities for impacting patient care, but also carry the potential for new iatrogenic injuries. Every step of every neurointerventional procedure carries risk, and a thorough appreciation of potential complications is fundamental to maximizing safety. This article presents the most frequent and dangerous iatrogenic injuries, their presentation, identification, prevention, and management.

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.

Postendarterectomy Cerebral Hyperperfusion Syndrome: The Etiological Significance of "Cerebral Reserve"

Postoperative cerebral hyperperfusion syndrome (CHS) in patients undergoing carotid intervention is thought to be related to the absence of cerebral reserve. Although hyperperfusion syndrome is rare, severe postoperative headache is common and is considered to be a prodromal sign. Cerebral reserve is measured by studying the response of cerebral vessels to a vasodilator such as hypercarbia. We produced hypercarbia by holding respiration for 60 seconds during carotid endarterectomy. We attempted to evaluate the relationship between intraoperatively evaluated cerebral reserve and the development of postoperative headache which was severe enough to require the patient to take an over the counter analgesic (e.g., ibuprofen, acetaminophen, aspirin). Internal carotid artery flow 1 (F1), Pco 2, and blood pressure 1 (BP1) were recorded before and after (F2, Pco 2, and BP2) 60 seconds of apnea. An increase in flow of > 20% was considered indicative of adequate cerebral reserve. Patients were evaluated before discharge and with follow-up calls at 2 to 5 days postdischarge. Fisher exact test was used to evaluate categorical predictors. Unpaired t test was used to compare continuous variables. Results were considered significant when p < 0.05. A total of 30 nonconsecutive patients were evaluated prospectively. Of the 30 patients, 4 (Group I) developed severe postoperative headache; 26 did not (Group II). Demographics were similar in both the groups. Three patients in Group I and 16 patients in Group II had > 20% increase in flow (p = 0.6315). Pco 2 rose in both groups and BP2 was unchanged from BP1 in both groups. Lack of cerebral reserve does not appear to be related to the development of severe postoperative headache.

Stenotic transverse sinus predisposes to poststenting hyperperfusion syndrome as evidenced by quantitative analysis of peritherapeutic cerebral circulation time

BACKGROUND AND PURPOSE

Hyperperfusion syndrome is a devastating complication of carotid stent placement. The shortening of cerebral circulation time after stent placement is seen as a good indicator of the development of hyperperfusion syndrome. The purpose of our study was to evaluate whether patients with ipsilateral transverse sinus stenosis are prone to having shortened cerebral circulation time after stent placement, subsequently leading to the possible development of hyperperfusion syndrome.

MATERIALS AND METHODS

Forty-nine patients with >70% unilateral carotid stenosis undergoing stent placement were recruited for analysis. Group A consisted of patients with a stenotic ipsilateral transverse sinus >50% greater than the diameter of the contralateral transverse sinus; the remaining patients were in group B. Quantitative DSA was used to calculate cerebral circulation time. Cerebral circulation time was defined as the time difference between the relative time to maximal intensity of ROIs in the proximal internal carotid artery and the internal jugular vein. ΔCCT was defined as cerebral circulation time before stent placement minus cerebral circulation time after stent placement. ΔCCT, white matter hyperintensity signals, and sulcal effacement in MR imaging were compared between the 2 groups.

RESULTS

ΔCCT was significantly shorter in group A (0.65 ± 1.3) than in group B (-0.12 ± 1.4). Three patients had white matter hyperintensity signals in group A, and 1 developed hyperperfusion syndrome. Group B showed no MR imaging signs of hyperperfusion syndrome.

CONCLUSIONS

Ipsilateral hypoplastic transverse sinus was associated with prolonged cerebral circulation time before stent placement and greatly shortened cerebral circulation time after stent placement. Inadequate venous drainage might play a role in impaired cerebral autoregulation and might influence the development of poststenting hyperperfusion syndrome.

Reversibility of ischemic findings on 3-tesla magnetic resonance T2(*)-weighted image after recanalization

Ischemic vessel signs (IVS) can be detected on 3-tesla T2(*)-weighted magnetic resonance images as a vessel enlargement at the territory of acute ischemia caused by major vessel occlusion or stenosis. Here, we studied changes in IVS before and after recanalization by the administration of intravenous recombinant tissue plasminogen activator (IV rtPA), carotid artery stenting or percutaneous transluminal angioplasty in patients with major vessel occlusion or stenosis. We performed magnetic resonance imaging for all patients treated by IV rtPA at the time of admission, shortly after and 24-72 hours after treatment with IV rtPA. We reviewed the IVS to assess its natural course of IVS by assessing patients who did not recanalize. IVS tended to disappear after recanalization. Conversely, in patients without recanalization, IVS did not disappear shortly after IV rtPA; rather, it disappeared 24-72 hours after IV rtPA, especially in the presence of complete infarction. Recanalization by IV rtPA or endovascular treatment contributed to improved clinical deficits or the prevention from further progression. IVS can be a parameter of misery perfusion and an important factor to detect the patients who have an indication of treatment for recanalization.

Percutaneous Treatment of Severe Intracranial Carotid and Middle Cerebral Artery Stenosis

Due to the lack of efficacy and durability data from prospective, randomized, multicenter trials, intracranial stenting remains investigational and should be used only in carefully selected patients after thorough evaluation of their clinical and anatomic factors. Stenting should not be performed in chronic total occlusions and asymptomatic lesions and generally should be avoided in very old patients, especially those with underlying dementia and severe calcification of their vessels. Symptomatic patients with angiographically documented greater than 70% stenosis and who have failed medical therapy are appropriate candidates for intracranial angioplasty and stenting and should be enrolled in clinical trials when possible.

Recurrent cerebral hyperperfusion syndrome after intracranial angioplasty and stenting: case report with review of literature

Cerebral hyperperfusion syndrome (CHS) describes a syndrome of sudden onset focal neurological features, unilateral headache, and systemic hypertension. Recurrent CHS in the same patient has not been described to date. We describe a 55-year-old woman who first developed CHS post intracranial stenting with sudden-onset right focal seizures and associated acute focal edema on imaging. After one and half years, the patient developed symptomatic in-stent restenosis and underwent repeat angioplasty with stenting. Postprocedure, the patient had another episode of CHS in the form of acute bleed in the basal ganglia and died. A review of literature of patients for CHS postintracranial angioplasty and stenting also was performed. The present case describes a rare clinical scenario where the patient had recurrent CHS with different clinical and imaging features.

Post-carotid endarterectomy cerebral hyperperfusion syndrome : is it preventable by strict blood pressure control?

Objective

Cerebral hyperperfusion syndrome (CHS) is a serious complication after carotid endarterectomy (CEA). However, the prevalence of CHS has decreased as techniques have improved. This study evaluates the role of strict blood pressure (BP) control for the prevention of CHS.

Methods

All 18 patients who received CEA from February 2009 through November 2012 were retrospectively reviewed. All patients were routinely managed in an intensive care unit by a same protocol. The cerebral perfusion state was evaluated on the basis of the regional cerebral blood flow (rCBF) study by perfusion computed tomography (pCT) and mean velocity by transcranial doppler (TCD). BP was strictly controlled (<140/90 mm Hg) for 7 days. When either post-CEA hyperperfusion (>100% increase in the rCBF by pCT or in the mean velocity by TCD compared with preoperative values) or CHS was detected, BP was maintained below 120/80 mm Hg.

Results

TCD and pCT data on the patients were analyzed. Ipsilateral rCBF was significantly increased after CEA in the pCT (p=0.049). Post-CEA hyperperfusion was observed in 3 patients (18.7%) in the pCT and 2 patients (12.5%) in the TCD study. No patients developed clinical CHS for one month after CEA. Furthermore, no patients developed additional neurological deficits related to postoperative cerebrovascular complications.

Conclusion

Intensive care with strict BP control (<140/90 mm Hg) achieved a low prevalence of post-CEA hyperperfusion and prevented CHS. This study suggests that intensive care with strict BP control can prevent the prevalence of post-CEA CHS.

Hyperperfusion syndrome after carotid endarterectomy and carotid stenting

BACKGROUND

Hyperperfusion syndrome (HS) is a relatively rare but possibly serious complication of carotid revascularization procedures. Impaired cerebral autoregulation and postrevascularization changes in cerebral blood flow are the main mechanisms involved in the development of HS. Most up-to-date studies addressing this issue are retrospective and tend to concentrate on carotid endarterectomy (CEA), neglecting carotid stenting (CAS). Our aim was to compare the frequency of clinical signs of HS and hyperperfusion detected by transcranial Doppler (TCD) in patients undergoing CAS or CEA due to carotid stenosis.

METHODS

In this prospective observational study, we evaluated 61 patients scheduled for routine CAS or CEA. Each patient was examined by a neurologist before and after the revascularization procedure to assess the clinical status. Severe headache, ocular or facial pain, confusion, visual disturbances, epileptic seizures or any focal deficits not caused by cerebral ischemia were considered clinical signs of HS. Peak systolic velocity (PSV), end-diastolic velocity, mean velocity (MV), and pulsatility index were measured by TCD once before and twice after the intervention (within 6 h after and 2-5 days after the procedure). Hyperperfusion was defined as a >100% increase in the middle cerebral artery (MCA) blood velocity, evaluated separately for PSV and MV after the procedure compared with the baseline value. Cerebrovascular reactivity (CVR) was evaluated with a TCD acetazolamide test before the intervention.

RESULTS

CAS (n = 33) and CEA (n = 28) patients were included in the study. There was no difference between the groups in the frequency of clinical signs of HS (21.2 vs. 21.4%) and ratio of TCD hyperperfusion (12.1 vs. 14.3%). In the CAS group, ipsilateral MCA velocity significantly increased directly after the intervention and 2-5 days later, while it increased in the CEA group only 2-5 days after the intervention. The sensitivity and specificity of hyperperfusion, defined by MV, for HS signs were 38.5 and 93.8%, respectively, whereas those defined by PSV were 30.8 and 89.6%, respectively. The sensitivity and specificity of impaired CVR (<25%) for HS signs were 63.6 and 73.5%, respectively.

CONCLUSIONS

There is no difference in the frequency of HS clinical signs and hyperperfusion detected by TCD between patients after CAE and CAS. Clinical signs suggested HS does not always correspond with TCD hyperperfusion. However, both the CVR test and TCD measurements of MCA velocity can help identify patients at high risk for HS.

Analysis of reserve capacity and subsequent stenting in a case of subacute occlusion of the internal carotid artery

Introduction

While acute internal carotid artery (ICA) occlusions are increasingly being treated with carotid angioplasty and stenting (CAS), the utility of CAS in subacute stages is unclear.

Case Report

A 65-year-old patient with an acute left ICA occlusion and pre-existing occlusion on the right side presented with dysarthria and central right-sided facial palsy. Carbon dioxide (CO₂) reactivity within the left hemisphere was markedly reduced. Due to acute deterioration despite maximal conservative therapy CAS was performed 8 days after the initial event with an excellent result and symptoms subsided.

Conclusion

CAS in subacute ICA occlusion is possible. Patients should be selected carefully. Assessment of cerebrovascular CO₂ reactivity might provide valuable information.

Management of tandem occlusion stroke with endovascular therapy

OBJECT

Approximately 25% of patients with middle cerebral artery (MCA) occlusion will have a concomitant internal carotid artery (ICA) occlusion, and 50% of patients with an ICA occlusion will have a proximal MCA occlusion. Cervical ICA occlusion with MCA embolic occlusion is associated with a low rate of recanalization and poor outcome after intravenous thrombolysis. The authors report their experience with acute ischemic stroke patients who suffered tandem ICA/MCA (TIM) occlusions and underwent intravenous thrombolysis followed by extracranial ICA angioplasty and intracranial MCA mechanical thrombectomy.

METHODS

In a retrospective analysis of their stroke database (2008-2011), the authors identified 2 patients with TIM occlusion treated with intravenous thrombolysis followed by extracranial ICA angioplasty and intracranial mechanical thrombectomy. They examined early neurological improvement defined by a greater than 10-point reduction of National Institutes of Health Stroke Scale (NIHSS) score and an improved modified Rankin Scale (mRS) score at 60 days. Successful recanalization based on thrombolysis in cerebral infarction (TICI) score of 2 or 3 was also evaluated.

RESULTS

In both patients a TICI score of 2b or 3 was achieved, signifying successful recanalization. In addition, both patients had a reduction in the NIHSS score by greater than 10 points and an mRS score of 0 at 60 days.

CONCLUSIONS

Tandem occlusions of the cervical ICA and MCA may be successfully treated using the multimodality approach of intravenous thrombolysis followed by extracranial ICA angioplasty and intracranial mechanical thrombectomy.

Cerebral hemodynamic benefits after contralateral carotid artery stenting in patients with internal carotid artery occlusion

CEA contralateral to an ICA occlusion is considered a surgical risk, and CAS may be an alternative for these patients. Our goal was to examine whether CAS improves cerebral hemodynamics on the treated side and on the side of the ICA occlusion, on the basis of measurement of CBF and CVR by using SPECT. The subjects were 8 patients who underwent contralateral CAS. Resting CBF and CVR to acetazolamide were measured by using (123)I-IMP SPECT before and chronically (3-6 months) after CAS. Resting CBF was also measured immediately (<2 hours) after CAS by using (123)I-IMP SPECT. There were no significant differences in resting CBF in both hemispheres immediately after CAS. However, resting CBF and CVR both significantly increased in the chronic period in both hemispheres. Contralateral CAS in patients with ICA occlusion resulted in cerebral hemodynamic improvement on the treated side and on the side of ICA occlusion.

Unilateral posterior reversible encephalopathy syndrome with hypertensive therapy of contralateral vasospasm: case report

BACKGROUND AND IMPORTANCE

Hemodynamic treatment of subarachnoid hemorrhage-induced vasospasm is associated with a number of systemic and cerebral risks. However, hypertensive encephalopathy has rarely been reported in the setting of induced hypertension. Recognition of this complication is nonetheless critical because failure to lower blood pressure may lead to worsening of deficits and even permanent injury.

CLINICAL PRESENTATION

This report details a case of unilateral hypertensive encephalopathy (also referred to as posterior reversible encephalopathy syndrome [PRES]) in a subarachnoid hemorrhage patient who was being treated with induced hypertension for symptomatic vasospasm affecting the contralateral hemisphere. This patient developed right hemispheric deficits associated with angiographic vasospasm of the right middle cerebral artery, which responded to induced hypertension. However, within 24 hours of raising blood pressure, the patient deteriorated with new left hemispheric deficits that paradoxically worsened when blood pressure was raised further in response. Computed tomography imaging was suspicious for evolving infarction in the left hemisphere, but on reevaluation, concern for PRES was raised. Magnetic resonance imaging confirmed left hemispheric PRES, and a dramatic neurological improvement occurred almost immediately after lowering blood pressure. Repeat CT showed resolution of the left hemispheric edema.

CONCLUSION

This is the first reported case of unilateral PRES in the setting of subarachnoid hemorrhage. It likely occurred because right-sided vasospasm attenuated ipsilateral distal perfusion pressures, leaving the left hemisphere vulnerable to the consequences of induced hypertension. Hypertensive encephalopathy should be considered in patients with unilateral or asymmetric vasospasm when neurological worsening occurs in the contralateral hemisphere during induced hypertension and/or the patient paradoxically worsens despite raising blood pressure.

Anesthesia for endovascular neurosurgery and interventional neuroradiology

This article outlines the roles of the anesthesiologist in the management of patients undergoing invasive endovascular procedures to treat vascular diseases, primarily of the central nervous system. This practice is usually termed interventional neuroradiology or endovascular neurosurgery. The article emphasizes perioperative and anesthetic management strategies to prevent complications and minimize their effects if they occur. Planning the anesthetic and perioperative management is predicated on understanding the goals of the therapeutic intervention and anticipating potential problems.

Stepwise revascularization by carotid endarterectomy after balloon angioplasty for symptomatic severe carotid artery stenosis

The authors report a novel stepwise carotid revascularization method to prevent perioperative complication. A 68-year-old man presented with left hemiparesis and dysarthria caused by severe stenosis of the right cervical internal carotid artery. According to the preoperative cerebral blood flow evaluation and plaque characterization, the patient was at risk for postoperative hyperperfusion and ischemic complications after carotid artery stenting. Initially, the patient underwent percutaneous angioplasty using an undersized balloon. Fifteen days later, the patient underwent a carotid endarterectomy. The surgical specimen obtained during the carotid endarterectomy showed the presence of typical vulnerable plaque. Of note was the complete preservation of the thin fibrous cap. The postoperative single-photon emission tomography images showed no signs of hyperperfusion, and the patient developed no neurological symptoms after each of the procedures.