Hyperperfusion Syndrome: Toward a Stricter Definition

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.

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.

Cerebral hyperperfusion syndrome after intracranial stenting: Case report and systematic review

BACKGROUND

Cerebral Hyperperfusion Syndrome (CHS) is an uncommon complication observed after intracranial angioplasty or stenting procedures. Given to the increasing use of new devices for intracranial angioplasty and stenting (INCS), in selected patients with high ischemic stroke risk, an equally increasing knowledge of complications related to these procedures is mandatory.Case description: a 63-year-old man was diagnosed with an hyperperfusion syndrome after percutaneous angioplasty and stenting for severe symptomatic right internal carotid artery (ICA) siphon stenosis. After treatment he complained generalized seizures and respiratory failure. While conventional imaging did not demonstrate any acute brain lesions, Pseudo-Continuous Arterial Spin Labeling (PCASL) Perfusion MRI early documented right hemisphere blood flow increase suggestive for CHS.

CONCLUSIONS

Monitoring of perfusion changes after INCS could play an important a role in determining patients with high risk of CHS. ASL Perfusion MRI might be used for promptly, early diagnosis of CHS after treatment of severe intracranial artery stenosis.

Clinical Predictors of Hyperperfusion Syndrome Following Carotid Stenting: Results From a National Prospective Multicenter Study

OBJECTIVES

The aim of the HISPANIAS (HyperperfusIon Syndrome Post-carotid ANgIoplasty And Stenting) study was to define CHS rates and develop a clinical predictive model for cerebral hyperperfusion syndrome (CHS) after carotid artery stenting (CAS).

BACKGROUND

CHS is a severe complication following CAS. The presence of clinical manifestations is estimated on the basis of retrospective reviews and is still uncertain.

METHODS

The HISPANIAS study was a national prospective multicenter study with 14 recruiting hospitals. CHS was classified as mild (headache only) and moderate-severe (seizure, impaired level of consciousness, or development of focal neurological signs).

RESULTS

A total of 757 CAS procedures were performed. CHS occurred in 22 (2.9%) patients, in which 16 (2.1%) had moderate-severe CHS and 6 (0.8%) had mild CHS (only headache). The rate of hemorrhages was 0.7% and was associated with high mortality (20%). Pre-operative predictors of moderate-severe CHS in multivariate analysis were female sex (odds ratio [OR]: 3.24; 95% confidence interval [CI]: 1.11 to 9.47; p = 0.03), older patients (OR: 1.09; 95% CI: 1.01 to 1.17; p = 0.02), left carotid artery treated (OR: 4.13; 95% CI: 1.11 to 15.40; p = 0.03), and chronic renal failure (OR: 6.29; 95% CI: 1.75 to 22.57; p = 0.005). The area under the curve of this clinical and radiological model was 0.86 (95% CI: 0.81 to 0.92; p = 0.001).

CONCLUSIONS

The rate of CHS in the HISPANIAS study was 2.9%, with moderate-severe CHS of 2.1%. CHS was independently associated with female sex, older age, history of chronic kidney disease, and a treated left carotid artery. Although further investigations are needed, the authors propose a model to identify high-risk patients and develop strategies to decrease CHS morbidity and mortality in the future.

Perioperative Stroke

PURPOSE OF REVIEW

This review overviews perioperative stroke as it pertains to specific surgical procedures.

RECENT FINDINGS

As awareness of perioperative stroke increases, so does the opportunity to potentially improve outcomes for these patients by early stroke recognition and intervention. Perioperative stroke is defined to be any stroke that occurs within 30 days of the initial surgical procedure. The incidence of perioperative stroke varies and is dependent on the specific type of surgery performed. This chapter overviews the risks, mechanisms, and acute evaluation and management of perioperative stroke in four surgical populations: cardiac surgery, carotid endarterectomy, neurosurgery, and non-cardiac/non-carotid/non-neurological surgeries.

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.

Cerebral Hyperperfusion Syndrome and Related Conditions

Cerebral vasoconstriction is a normal physiological response under determined conditions to preserve a normal cerebral blood flow. However, there are several syndromes, with impaired cerebral autoregulation and cerebral vasoconstriction, not related with infection or inflammation, which share the same radiological and clinical presentation. We review here the cerebral hyperperfusion syndrome and related conditions such as hypertensive encephalopathy, posterior reversible encephalopathy syndrome, and reversible cerebral vasoconstriction syndrome. These syndromes might share the same pathophysiological mechanism with endothelial damage, cerebral vasoconstriction, blood-brain barrier disturbance, cerebral edema, and, occasionally, intracerebral hemorrhage, with fatal cases described in all. Despite knowledge of these syndromes, they still remain unknown to us. Why these entities present in some patients and not in others goes further than the actual understanding of these diseases. We have to consider that a genetic susceptibility and molecular disturbances may be involved. Thus, more studies are needed in order to better characterize such syndromes.

Neurologic complications in patients with carotid artery stenting

Objective

Carotid artery stenting is helpful in patients with carotid artery stenosis and is a common method of treatment. However, data on the neurological consequences that might arise from, especially Asian patients after CAS is not enough. The purpose of this study was to investigate the outcome and prognostic factors affecting CAS patients.

Methods

From January 2013 to June 2018 it was enrolled 97 patients who underwent CAS with severe carotid artery stenosis in a single institution. We retrospectively reviewed neurologic complications such as restenosis, ipsilateral or contralateral stroke, and hyperperfusion during the 6-month follow-up period.

Results

There were no complication occured during the procedure in all 97 patients. Neurologic complications occurred in 30 patients (30.9%) after the procedure, and ipsilateral stroke 6 (6.2%), contralateral stroke 9 (9.4%), restenosis 2 (2.1%) and hyperperfusion 13 respectively. One of them had died (1.0%), of which the rest were discharged after symptoms improve. On univariate analysis, DM and pre-op NIHSS score was associated with the risk of CAS complication, exclusively. On the binary logistic regression for risk factors, DM (OR 0.144, 95% CI [0.029-0.718]), history of radiotheraphy (OR 36.103, 95% CI [1.009-1291.789]) and preoperative NIHSS (OR 1.266, 95% CI [1.059-1.513]) showed independent risk factors associated with post procedural neurological complications, statistically.

Conclusion

Carotid artery stenting is a relatively safe and reliable long-term outcome for patients with carotid artery stenosis. However, careful observation should be taken after procedure immediately for any possible complications.

Transient Cerebral Vasospasm After Carotid Artery Stenting: A Case Report and Literature Review

BACKGROUND

Cerebral embolism after carotid artery stenting (CAS) is a well-known complication, but cerebral ischemia owing to cerebral vasospasm after CAS is rare and has seldom been reported. We describe a patient with transient ischemic complications owing to reversible cerebral vasospasm of the middle cerebral artery after CAS.

CASE DESCRIPTION

A 74-year-old man presented with right hemiparesis caused by acutely scattered brain infarction in the left cerebral hemisphere. Magnetic resonance angiography showed severe stenosis of the left cervical internal carotid artery origin. CAS under a distal filter protection was performed without any intraprocedural complications, but 12 hours later, the patient had aphasia and Gerstmann syndrome. Urgent magnetic resonance imaging revealed no evidence of an intracranial hemorrhage or new cerebral infarction. However, magnetic resonance angiography showed diffuse vasospasm of the left middle cerebral artery. His symptoms and imaging findings improved gradually with conservative treatment. The patient was discharged without new neurologic deficit or recurrent attack 3 weeks after CAS.

CONCLUSIONS

In a patient with delayed neurologic symptoms after CAS, the possibility of cerebral vasospasm should be kept in mind to select appropriate treatment.

Hemodynamic Surveillance of Unilateral Carotid Artery Stenting in Patients With or Without Contralateral Carotid Occlusion by TCD/TCCD in the Early Stage Following Procedure

Objective: To evaluate the cerebral hemodynamic variations in patients with unilateral carotid artery stenosis and contralateral carotid occlusion (CCO) in hours following carotid artery stenting (CAS) by transcranial Doppler (TCD) or transcranial color-code Doppler (TCCD).

Methods: Sixty-five consecutive patients who underwent unilateral CAS were enrolled. Among them, 14 patients had ipsilateral severe stenosis and CCO (CCO group) while the other 51 patients had only unilateral severe carotid stenosis without CCO (UCS group). All patients underwent TCD or TCCD monitoring before, at 1 and 3 h after CAS. We monitored bilateral middle cerebral artery (MCA) peak systolic velocity (PSV), pulsatility index (PI), and blood pressure (BP), and compared that data between two groups.

Results: In UCS group, ipsilateral MCA PSV increased relative to baseline at 1 h (96 ± 30 vs. 85 ± 26 cm/s, 15%, P < 0.001) and 3 h (97 ± 29 vs. 85 ± 26 cm/s, 17%, P < 0.001) following CAS. Significant PI increases were observed at 1 and 3 h following CAS on the ipsilateral side. In CCO group, ipsilateral MCA PSV increased relative to baseline at 1 h (111 ± 30 vs. 83 ± 26 cm/s, 35%, P < 0.001) and 3 h (107 ± 28 vs. 83 ± 26 cm/s, 32%, P <0.001) following CAS. The magnitude of ipsilateral MCA PSV increase was significantly higher in CCO group compared with UCS group at 1 h (P = 0.002) and 3 h (P = 0.024) following CAS, while BP similarly decreased between the two groups. On the contralateral side, significant MCA PSV increases were observed following CAS in CCO group but not in UCS group. Bilateral MCA PSV increases were higher in patients with a stenosis degree of ≥90% than in patients with stenosis degree of 70–89% only in CCO group.

Conclusion: The ipsilateral MCA PSV and PI increase moderately in the initial hours after unilateral CAS in patients without CCO. In patients with CCO, the ipsilateral, and contralateral MCA PSV increase significantly in the early stage following CAS. CCO is a factor of the increased blood flow velocity in ipsilateral MCA after unilateral CAS.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Longitudinal assessment of cerebral blood flow changes following carotid artery stenting and endarterectomy

BACKGROUND

Carotid artery stenting (CAS) and endarterectomy (CEA) are major treatment strategies for patients with internal carotid artery (ICA) stenosis; however, the dynamic cerebral blood flow (CBF) changes after CAS and CEA remain unclear.

PURPOSE

This study aimed to monitor consecutive CBF changes at 24-h intervals in patients who underwent CAS and CEA to explore the potential pattern of CBF alternation and compare the effect on CBF changes of different surgical methods.

METHODS

Thirty-two patients (28 males and 4 females; age = 63.0 ± 7.3 years) with 70-99% ipsilateral stenosis in the ICA were enrolled, of which 19 underwent CAS and 13 underwent CEA by prospective cross-sectional study. Routine head MRI and three-dimensional pseudo-continuous arterial spin labeling were performed using a 3.0-T system within 7 days prior to operations, and at 4 consecutive time-points (24, 48, 72, and 96 h) after operations. Comparisons within groups were made using paired t test, and comparisons between groups were made using independent-sample t test.

RESULTS

The CBF values markedly increased at 24 h after CAS and CEA (P < 0.05) compared with baseline. Most patients showed peak CBF values on the ipsilateral side at 72 h (13/19, 68%) after CAS and at 48 h (10/13, 77%) after CEA, which then declined. The CBF values for the ipsilateral ICA territory of CEA group were higher than those of CAS group at 24, 48, 72, and 96 h (P < 0.05).

CONCLUSIONS

The pattern of dynamic CBF changes is different after CAS and CEA, which may be helpful for the improvement of the patient's postoperative management.

Intracranial hemorrhage after carotid artery stenting in both anterior and posterior circulation: A case report

RATIONAL

Intracranial hemorrhage (ICH) after carotid artery stenting (CAS) is a rare but fatal complication, and it primarily occurs in the corresponding vascular distribution area. Herein, a case of ICH after CAS in both anterior and posterior circulation has been described.

PATIENT CONCERNS

A 62-year-old female was referred to the hospital for left-side limb weakness and right nasal hemianopia for 1 month.

DIAGNOSIS

Cerebral MRI following hospitalization revealed cerebral infarction in the right posterior cortical watershed area. Computed tomography angiography (CTA) showed severe stenosis in the right internal carotid artery.

INTERVENTIONS

We performed CAS to treat the right internal carotid artery stenosis without any complications.

OUTCOMES

After CAS, cerebral hemorrhage occurred under strict control of blood pressure in both anterior and posterior circulation. After 69 days of treatment, the patient was discharged from the hospital.

LESSONS

Hypertension is still one of the causes of ICH after CAS. The control of perioperative BP in patients with severe carotid stenosis is yet a major concern.

The protective effect of melatonin on brain ischemia and reperfusion in rats and humans: In vivo assessment and a randomized controlled trial

Carotid endarterectomy (CEA) is the treatment of choice for carotid stenosis. Some patients develop ischemia and reperfusion (I/R) injury after CEA. This study was designed to investigate the neuroprotective effects of melatonin on I/R injury in both rats and humans. To this end, 36 male rats were evaluated, and a double-blind randomized controlled trial (RCT) including 60 patients was performed. A rat model of middle cerebral artery occlusion was used to mimic cerebral I/R. After 2 hour of occlusion and 24 hour of reperfusion, blood samples and brain tissues were harvested for further assessments. Compared with the vehicle treatment, melatonin decreased the expression of nuclear factor κ light-chain-enhancer of activated B cells (NF-κB) and S100 calcium-binding protein β (S100β) (P < 0.05) and markedly increased the expression of nuclear erythroid 2-related factor 2 (Nrf2), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) (P < 0.05). The participants in the RCT took 6 mg/d melatonin orally from 3 days before surgery to 3 days after surgery. Blood samples were drawn at the following times: baseline; pre-anesthesia; carotid reconstruction completion; and 6, 24, and 72 hour after CEA. Compared with the oral placebo treatment, melatonin decreased the expression of NF-κB, tumor necrosis factor-α, interleukin-6 (IL-6), and S100β (P < 0.05) and increased the expression of Nrf2, SOD, CAT, and GPx (P < 0.05) in patients after CEA. Our findings suggested that melatonin could ameliorate brain I/R injury after CEA and that this outcome was essentially due to the antioxidant and anti-inflammatory effects of melatonin.

Right carotid-cutaneous fistula and right carotid pseudoaneurysm formation secondary to a chronically infected polyethylene terephthalate patch

Carotid endarterectomy (CEA) remains the treatment for significant carotid stenosis and stroke prevention. Approximately 100,000 CEAs are performed in the United States every year. Randomized trials have demonstrated an advantage of patch carotid angioplasty over primary closure. Complications from patches include thrombosis, transient ischemic attack, stroke, restenosis, pseudoaneurysm (PA), and infection. PA after CEA is rare, with a reported average of 0.37% of cases. We describe an unusual case of PA after polyethylene terephthalate (PTFE) patching for CEA. An 88-year-old female with Alzheimer's disease living in a nursing facility with a history of skin cancer on her right chest developed a new area of intermittent brisk bleeding on her right neck which was initially believed to be related to her skin cancer. She had a remote history of right CEA with a PTFE patch approximately a decade ago. A computed tomography angiograph-head-and-neck with showed a partially thrombosed PA in the region of her right common carotid artery bifurcation with a tract containing gas and fluid extending to the skin surface suspicious for a partially thrombosed, leaking PA. She was taken urgently to the operating room on broad-spectrum antibiotics where we performed a right neck exploration, ligation of a bleeding carotid PA by ligation of the right common, internal, and external carotid arteries, explantation of a chronically infected polyethylene terephthalate patch, and closure with a sternocleidomastoid advanced flap with multilayered closure. She was discharged to her nursing facility with 6 weeks of ceftriaxone intravenous (IV) and metronidazole IV through a peripherally inserted central catheter (PICC) line with no neurological sequelae.

Quantitative magnetic resonance angiography as a potential predictor for cerebral hyperperfusion syndrome: a preliminary study

OBJECTIVE

Cerebral hyperperfusion syndrome (CHS) is a rare but devastating complication of carotid endarterectomy (CEA). This study sought to determine whether quantitative hemodynamic assessment using MR angiography can stratify CHS risk.

METHODS

In this prospective trial, patients with internal carotid artery (ICA) stenosis were randomly selected for pre- and postoperative quantitative phase-contrast MR angiography (QMRA). Assessment was standardized according to a protocol and included Doppler/duplex sonography, MRI, and/or CT angiography and QMRA of the intra- and extracranial supplying arteries of the brain. Clinical and radiological data were analyzed to identify CHS risk factors.

RESULTS

Twenty-five of 153 patients who underwent CEA for ICA stenosis were randomly selected for pre- and postoperative QMRA. QMRA data showed a 2.2-fold postoperative increase in blood flow in the operated ICA (p < 0.001) and a 1.3-fold increase in the ipsilateral middle cerebral artery (MCA) (p = 0.01). Four patients had clinically manifested CHS. The mean flow increases in the patients with CHS were significantly higher than in the patients without CHS, both in the ICA and MCA (p < 0.001). Female sex and a low preoperative diastolic blood pressure were the clearest clinical risk factors for CHS, whereas the flow differences and absolute postoperative flow values in the ipsilateral ICA and MCA were identified as potential radiological predictors for CHS.

CONCLUSIONS

Cerebral blood flow in the ipsilateral ICA and MCA as assessed by QMRA significantly increased after CEA. Higher mean flow differences in ICA and MCA were associated with the development of CHS. QMRA might have the potential to become a noninvasive, operator-independent screening tool for identifying patients at risk for CHS.

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.

Changes in Blood Flow Velocity of the Middle Cerebral Artery After Carotid Endarterectomy: Daily Assessment with Transcranial Color-Coded Sonography

BACKGROUND

Hyperperfusion syndrome (HPS) is a well-known complication of carotid endarterectomy (CEA) warranting repeatable inexpensive monitoring. Transcranial color-coded sonography (TCCS) may provide a potential modality for such monitoring, but little is known about TCCS trends after CEA.

METHODS

Between January 2016 and February 2017, we prospectively included patients with CEA at our institute in this study. TCCS was performed preoperatively and repeated daily from the operation day until postoperative day (POD) 7. Daily trends in mean flow velocity (MFV) at the M1 portion of the middle cerebral artery were compared between patients with and without HPS.

RESULTS

Among 35 patients with CEA, daily TCCS monitoring was performed in 18 patients (mean age ± SD, 72 ± 7 years; male/female, 17:1). Among these 18 patients, 3 had probable HPS. On POD 0, MFV of the 18 patients showed a 32% increase from the initial preoperative value (from 52.5 to 69.4 cm/s, P = 0.0013). This increased MFV lasted for several days and recovered gradually by POD 7. Patients with probable HPS demonstrated a trend to higher MFV than those without; however, the difference was below the significance level.

CONCLUSIONS

We used daily TCCS after CEA to depict cerebral blood flow changes after CEA in our cohort. This technique may be useful both for the detection and prevention of HPS.

Intracerebral hemorrhage as a manifestation of cerebral hyperperfusion syndrome after carotid revascularization: systematic review and meta-analysis

BACKGROUND

Intracerebral hemorrhage (ICH) in the context of cerebral hyperperfusion syndrome (CHS) is an uncommon but potentially lethal complication after carotid revascularization for carotid occlusive disease. Information about its incidence, risk factors and fatality is scarce. Therefore, we aimed to perform a systematic review and meta-analysis focusing on the incidence, risk factors and outcomes of ICH in the context of CHS after carotid revascularization.

METHODS

We searched the PubMed and EBSCO hosts for all studies published in English about CHS in the context of carotid revascularization. Two reviewers independently assessed each study for eligibility based on predefined criteria. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and the PROSPERO register was made (register no. CRD42016033190), including the pre-specified protocol.

RESULTS

Forty-one studies involving 28,956 participants were deemed eligible and included in our analysis. The overall quality of the included studies was fair. The pooled frequency of ICH in the context of CHS was 38% (95% CI: 26% to 51%, I2 = 84%, 24 studies), and the pooled case fatality of ICH after CHS was 51% (95% CI: 32% to 71%, I2 = 77%, 17 studies). When comparing carotid angioplasty with stenting (CAS) with carotid endarterectomy (CEA), post-procedural ICH in the context of CHS was less frequent in CEA. ICH following CHS occurred less often in large series and was rare in asymptomatic patients. The most common risk factors were periprocedural hypertension and ipsilateral severe stenosis.

CONCLUSIONS

ICH as a manifestation of CHS is rare, more frequent after CAS and associated with poor prognosis. Periprocedural control of hypertension can reduce its occurrence.

Cerebral hyperperfusion syndrome and intracranial hemorrhage after carotid endarterectomy or carotid stenting: A meta-analysis

INTRODUCTION

Cerebral hyperperfusion syndrome (CHS) and intracranial hemorrhage (ICH) after carotid revascularization have been associated with significant morbidity and mortality, although pooled data comparing these outcomes between open and endovascular treatment are lacking. Aim of this meta-analysis is to compare CHS and ICH risk between carotid endarterectomy (CEA) and carotid angioplasty with stenting (CAS).

METHODS

A systematic literature review was conducted conforming to established criteria, in order to identify eligible articles published prior to February 2017. Eligible studies compared CHS and/or ICH between patients undergoing CEA and CAS. Other outcomes evaluated in this review included stroke and death due to ICH. Outcome risks are presented as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Overall, 6 studies (5 studies reporting on CHS and 4 studies reporting on ICH) included 236,537 procedures (218,144 CEA; 18,393 CAS) in total. CEA was associated with a higher risk for CHS compared to CAS (pooled OR=1.432 [95% CI=1.078-1901]; P=0.015), although this difference was generated mainly from older studies (prior to 2012). However, no difference was found regarding ICH risk between the two methods (pooled OR=0.544 [95% CI=0.111-2.658]; P=0.452). Regarding stroke incidence, no difference was found between the two methods as well, although this resulted mainly from studies with a higher volume of CAS procedures (pooled OR=0.964 [95% CI=0.741-1.252]; P=0.833). Finally, death rate was significantly higher among patients with ICH compared to patients without ICH (pooled OR=386.977 [95% CI=246.746-606.906]; P<0.0001). Pooled data were not adequate to calculate potential risk factors for CHS/ICH after CEA compared to CAS.

CONCLUSIONS

CEA seems to be associated with a higher risk for CHS compared to CAS, although this difference was generated mainly from older studies. However, there seems to be no difference regarding ICH risk between the two methods, with ICH being associated with a significantly higher risk for death.

Analysis of Hemodynamic Changes in Early Stage after Carotid Stenting by Transcranial Doppler-A Preliminary Study

BACKGROUND

Cerebral hyperperfusion syndrome or hemodynamic instability, caused by the hemodynamic changes, often occur within 6 hr after carotid artery stenting (CAS) The postprocedure cerebral hemodynamic change in the early phase, <6 hr after CAS, is largely unknown. In this study, we evaluated the cerebral hemodynamic changes in patients after CAS using transcranial Doppler (TCD).

METHODS

From January 2013 to July 2014, medical records of 61 patients who underwent CAS were reviewed retrospectively. Among them, 44 patients had TCD examination before CAS, 1-2 and 3-4 hr after CAS. In the TCD examination, middle cerebral artery (MCA) peak systolic velocity (PSV) and pulsatility index (PI) on the ipsilateral and contralateral sides were measured. Blood pressure, MCA PSV, and PI data were collected and analyzed from the 44 patients who had valid TCD examinations.

RESULTS

Blood pressure was 148.4 ± 14.5 mm Hg before CAS: 124.5 ± 13.8 mm Hg 1-2 hr after CAS, and 121.6 ± 12.6 mm Hg 3-4 hr after CAS. On the ipsilateral side, the MCA PSV increased from 85.7 ± 22.8 cm/s before CAS to 101.1 ± 27.1 cm/s (19.9%, P < 0.001) 1-2 hr after CAS, and 99.7 ± 27.0 cm/s (18.2%, P < 0.001) 3-4 hr after CAS. There was no significant difference in MCA PSV between 1-2 and 3-4 hr after CAS (P = 0.200). The PI increased from 0.871 ± 0.167 before CAS to 0.941 ± 0.205 (P = 0.022) 1-2 hr after CAS, and 0.954 ± 0.218 (P = 0.010) 3-4 hr after CAS. On the contralateral side, there was no statistically significant PSV increase in the MCA following CAS.

CONCLUSIONS

CAS may induce a significant increase in PSV and PI in the ipsilateral MCA within 4 hr. The MCA PSV increased significantly higher than that on the contralateral side. The PSV had no significant change between 1-2 and 3-4 hr after CAS.

Signal changes on magnetic resonance perfusion images with arterial spin labeling after carotid endarterectomy

BACKGROUND

Cerebral hyperperfusion after carotid endarterectomy (CEA) is defined as an increase in ipsilateral cerebral blood flow (CBF). Practically, however, prompt and precise assessment of cerebral hyperperfusion is difficult because of limitations in the methodology of CBF measurement during the perioperative period. Arterial spin labeling (ASL) is a completely noninvasive and repeatable magnetic resonance perfusion imaging technique that uses magnetically-labelled blood water as an endogenous tracer. To clarify the usefulness of ASL in the management of cerebral hyperperfusion, we investigated signal changes by ASL with a single 1.5-s post-labeling delay on visual inspection.

METHODS

Thirty-two consecutive patients who underwent CEA were enrolled in this retrospective study.

RESULTS

On postoperative day 1, 22 (68.8%) and 4 (12.5%) patients exhibited increased ASL signals bilaterally (Group A) and on the operated side (Group B), respectively. Follow-up ASL showed improvement in these findings. Six (18.8%) patients showed no change (Group C). There was no apparent correlation between ASL signals on postoperative day 1 and the preoperative hemodynamic state, including the cerebrovascular reserve (P = 0.2062). Three (9.4%) patients developed cerebral hyperperfusion syndrome (two in Group A and one in Group B). Coincidence in the localization of increased ASL signals and electroencephalographic abnormalities was noted in these patients.

CONCLUSION

Visual analysis of ASL with a single post-labeling delay overestimates CBF and cannot identify patients at risk of cerebral hyperperfusion syndrome probably because of the strong effect of the shortened arterial transit time immediately after CEA. However, ASL may be used as for screening.

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

Background

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

Materials and methods

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

Results

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

Conclusion

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

Hyperperfusion Syndrome After Stenting for Intracranial Artery Stenosis

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

Intraoperative middle cerebral artery pressure measurements during superficial temporal artery to middle cerebral artery bypass procedures in patients with cerebral atherosclerotic disease

OBJECTIVE

No previous study has monitored middle cerebral artery (MCA) pressure during the superficial temporal artery (STA)-MCA bypass procedure for cerebral atherosclerotic disease. In this paper, the authors describe their method of monitoring MCA pressure and report their initial data on intraoperative MCA pressure and its relationship with hemodynamics prior to and after the bypass procedures.

METHODS

The results from a total of 39 revascularization procedures performed between 2004 and 2014 were analyzed. The patient group included 27 men and 12 women, and their mean age at surgery was 67.6 years (range 39–83 years). The authors investigated the MCA pressure via the STA during STA-MCA bypass procedures. After one branch of the STA was anastomosed to the MCA, the other branch was connected to an arterial line, and a clip was placed temporally on the main STA trunk to monitor the pre-anastomosis MCA pressure. Simultaneously, the radial artery (RA) pressure was determined before removing the temporal clip to measure the post-anastomosis MCA pressure. The relationship between MCA pressures and single photon emission computed tomography findings and the risk factors for hyperperfusion after STA-MCA bypass were analyzed.

RESULTS

The MCA/RA (%) pressure was significantly correlated with that of the resting stenotic/normal side cerebral blood flow (CBF) ratio (%) in the linear regression analysis (slope 1.200, r2 = 0.3564, F = 20.49, p < 0.0001). The intraoperative MCA pressure was 39.3% of RA pressure in patients with Powers' Stage 2 cerebral atherosclerotic disease. After 1 branch of the STA was anastomosed, the intraoperative MCA pressure increased to 75.3% of the RA pressure. The rate of increase in pressure was significantly correlated with the increase in the STA diameter in the linear regression analysis (slope 2.59, r2 = 0.205, F = 9.549, p = 0.0038). Hyperperfusion occurred in 2 cases. When mean values for these 2 patients were compared with those for the 37 patients without hyperperfusion, significant differences were found in the stenotic/normal side CBF ratio (p = 0.0001), pre-anastomosis MCA pressure (p = 0.02), rate of increase in pressure (p = 0.02), pre-anastomotic MCA/RA pressure ratio (p = 0.01), vascular reserve (p = 0.0489), and STA diameter (p = 0.0002).

CONCLUSIONS

The measurement of intraoperative MCA pressure may be a useful technique to assess cerebral perfusion and for predicting the risk of hyperperfusion. Monitoring MCA pressure is recommended during STA-MCA bypass procedures for atherosclerotic disease.

Intraoperative Perfusion Computed Tomography in Carotid Endarterectomy: Initial Experience in 16 Cases

BACKGROUND This study aimed to evaluate the changes in perfusion computed tomography (PCT) parameters in carotid endarterectomy (CEA), and to discuss the use of intraoperative PCT in CEA. MATERIAL AND METHODS Sixteen patients with carotid stenosis who also underwent CEA with intraoperative CT were recruited in this study. We calculated quantitative data on cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), and the relative parameter values, including relative CBF (rCBF), relative CBV (rCBV), and relative TTP (rTTP). The role of PCT was assessed and compared to conventional monitoring methods. RESULTS There were no significant differences in any of the parameters in the anterior cerebral artery (ACA) territory (P>0.05). In the middle cerebral artery (MCA) territory, the CBF and CBV increased and TTP decreased in the operated side during CEA; the rCBF and rCBV increased and the rTTP decreased significantly (P<0.05). In 16 patients, CT parameters were improved, SSEP was normal, and MDU was abnormal. In 3 patients, CBF increased by more than 70% during CEA. Relative PCT parameters are sensitive indicators for detecting early cerebral hemodynamic changes during CEA. Cerebral hemodynamics changed significantly in the MCA territory during CEA. CONCLUSIONS Intraoperative PCT could be an important adjuvant monitoring method in CEA.

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.

[Peri-interventional management of acute endovascular stroke treatment]

Due to the ground breaking consistent evidence that supports the effect of endovascular stroke treatment (EST), many acute care hospitals and stroke centers will have to be prepared to provide this treatment in an optimal way within the coming years. In addition to the intervention itself, patient preparation, stabilization and monitoring during the treatment as well as the aftercare represent significant challenges and have mostly not yet been sufficiently investigated. Under these aspects, the questions of optimal sedation and airway management have received the highest attention. Based on retrospective study results it already seems to be justified, respecting certain criteria, to prefer EST with the patient under conscious sedation (CS) in comparison to general anesthesia (GA) and to only switch to GA in cases of emergency until this question has been clarified by prospective studies. This and other aspects of peri-interventional management, such as logistics, monitoring, blood pressure, ventilation settings, postprocedural steps of intensive or stroke unit care and imaging follow-up are summarized in this overview. The clinical and radiological selection of patients and thus the decision for intervention or technical aspects of the intervention itself will not be part of this article.

Brain Injury Secondary to Carotid Intervention

Causes of brain injury during endovascular carotid intervention are protean. Mechanisms of injury include embolic and hemodynamic events, acute carotid occlusions occurring through a variety of means, and the relatively rare contrast-induced encephalopathy.

Embolic injury may result from micro- and macroembolization and most commonly causes ischemic stroke when sufficiently severe. Hemodynamic injury may proceed from hemodynamic depression and hypoperfusion (which may result in watershed infarction) or the hyperperfusion syndrome, which may, if severe, result in hemorrhagic stroke.

Embolic and dynamic causes of stroke may either occur intraprocedurally or at a variable time after stent placement and may be co-related. Impaired clearance of emboli due to relative hypoperfusion may exacerbate their clinical relevance. Other causes of stroke include acute carotid occlusions, which most commonly occur procedurally due to flow-limiting spasm, acute dissection, and, if a filter-type cerebral protection device has been used, filter occlusion due to a large trapped embolic load. These scenarios may result in stroke if not recognized and dealt with appropriately. Acute stent thrombosis may occur within 24 hours of the procedure as a result of adverse hemodynamic factors or suboptimal patient response to procedural heparin and antiplatelet agents, or it may occur after the procedure, again perhaps as a result of suboptimal response to antiaggregate drugs.

Cardiovagal and adrenergic function tests in unilateral carotid artery stenosis patients-a Valsalva manoeuvre tool to show an autonomic dysfunction?

BACKGROUND

The stability of an arterial baroreflex depends also upon the integrity of the afferent limb. For its quantification, we can use a noninvasive test such as baroreceptor sensitivity estimation during Valsalva manoeuvre. The aim of this study was to evaluate potential autonomic dysfunction in patients with unilateral severe carotid disease and compare the results to the results obtained from an age and gender matched group of healthy volunteers.

METHODS

We evaluated dynamic changes during Valsalva manoeuvre (Valsalva ratio, cardiovagal and adrenergic baroreceptor sensitivity, sympathetic indexes and its dynamic ranges) in 41 patients (29 males; 62.9 ± 7.4 years) and compared the results to results obtained from volunteers (62.8 ± 7.0 years).

RESULTS

Valsalva ratio between the patients and control group revealed no significant difference, as well as cardiovagal and adrenergic baroreceptor sensitivity. Sympathetic indexes, except for sympathetic index 2, reflecting the sympathetic vasoconstrictor baroreceptor response in late phase 2 of Valsalva manoeuvre (7.1 ± 13.1 mmHg in patients vs. 11.4 ± 10.2 mmHg in control group; p = 0.012) showed no significant differences between the studied groups. The most prominent dynamic range between the groups was within the sympathetic index 2.

CONCLUSION

With some Valsalva manoeuvre test results, we were not able to show severe autonomic dysfunction in unilateral severe carotid stenosis patients except for lower vasoconstriction response within the late phase 2 of the manoeuvre.

Loss of labelling efficiency caused by carotid stent in pseudocontinuous arterial spin labelling perfusion study

AIM

To elucidate the cause of cerebral hypoperfusion on the stent placement side after carotid artery stent placement (CAS) measured by pseudocontinuous arterial spin labelling (PCASL) perfusion imaging.

MATERIALS AND METHODS

Consecutive patients with symptomatic internal carotid artery stenosis receiving CAS were included in the study. Cerebral blood flow (CBF) was measured by PCASL perfusion imaging at 3 T magnetic resonance imaging (MRI) the day before and 3 days after the procedure. Changes in cerebral haemodynamics after CAS were assessed.

RESULTS

Twenty-two patients were included; 17 patients had increased or stationary CBF after CAS and five patients had significantly reduced CBF on the stenting side after CAS whereas CBF increased on the contralateral side. High stent position was noticed in the five patients. After labelling plane adjustment to avoid labelling on the stent, no more cerebral hypoperfusion was noticed.

CONCLUSION

When using PCASL perfusion imaging to monitor post-stenting CBF, the stent may cause an artefact that leads to a low CBF in the territory of the stented vessel. Routinely adding a fast T2 star gradient-echo echo-planar-imaging covering the upper neck region before PCASL perfusion imaging to identify the stent position and avoid the stent-related artefact is recommended.

Simple cardiovagal and adrenergic function tests in carotid artery stenosis patients as a potential tool for determining a transient autonomic dysfunction

PURPOSE

The arterial baroreflex depends on the integrity of the afferent limb, which can be quantified using the baroreceptor's sensitivity (BRS) during the Valsalva maneuver (VM). The aim of this study was to evaluate, using autonomic nervous system tests, the autonomic function in patients after a carotid artery angioplasty (CAS).

METHODS

We evaluated the changes in blood pressure (BP) during the VM (Valsalva ratio, BRS, sympathetic indexes) in 41 patients with symptomatic, unilateral, internal carotid artery stenosis.

RESULTS

The Valsalva ratio between the baseline and the post-procedural day (1.3 ± 0.1 vs 1.44 ± 0.3; P = 0.002) and the post-procedural day and a month later (1.44 ± 0.3 vs 1.3 ± 0.3; P = 0.0002) revealed significant differences. This was confirmed with a cardiovagal BRS test. However, the adrenergic BRS did not reveal any differences. Sympathetic indexes [BP fall (SI1) and recovery during phase 2 (SI2)] showed differences for the periods before and a day after the treatment (36.9 ± 18.0 vs 27.2 ± 21.4 and 7.1 ± 13.1 vs 3.0 ± 8.2, respectively; P = 0.004) and for SI1 a day and a month after the treatment (27.2 ± 21.4 vs 37.1 ± 21.8; P = 0.036). The dynamic ranges between S1 and S3 (the difference in the BP between the baseline and the end of phase 2) were also different (P = 0.007 and P = 0.044, respectively).

CONCLUSION

We found heterogeneous responses in the BP regulation obtained with the Valsalva maneuver in our patients; however, we could not confirm that CAS provoked any long-term autonomic dysfunction, except for 1 day after the procedure.

Cerebral hyperperfusion syndrome after endovascular covered stent grafting for a giant extracranial aneurysm of the internal carotid artery

Symptomatic giant extracranial internal carotid artery (ICA) aneurysm is a rare and surgically intractable disease. Several authors have described successful treatments for extracranial ICA aneurysm. None, however, have described a perioperative evaluation of cerebral perfusion or a postoperative complication of cerebral hyperperfusion syndrome (CHS). We present a rare case of CHS after endovascular covered stent grafting for a giant extracranial ICA aneurysm. The CHS was successfully managed on the basis of hemodynamic monitoring. CHS can appear after endovascular reconstruction of an extracranial ICA aneurysm, and perioperative repeated evaluation of cerebral perfusion allows safe and effective management of CHS.

Carotid Stenting in Asymptomatic Carotid Stenosis: The Calgary Experience

Background:

Although carotid endarterectomy is considered the ‘gold standard’ for standard risk symptomatic patients, the treatment of choice for asymptomatic patients remains controversial. Carotid stenting has demonstrated real-world outcomes consistent with established guidelines for carotid endarterectomy in asymptomatic high-surgical risk patients in recent prospective multicenter trials. We describe our experience with asymptomatic patients who underwent carotid stenting at our center in a routine clinical setting.

Methods:

This is a retrospective, longitudinal cohort study of patients who underwent carotid angioplasty and stenting at the Foothills Medical Center, Calgary, Canada between 1997 and 2007. The qualifying events were categorized as symptomatic and asymptomatic. The procedures were performed by four experienced neurointerventionists. The primary outcome was stroke or death at 30-day follow- up.

Results:

243 patients underwent 255 carotid stenting procedures. Their ages ranged from 50 to 83 years; the mean age was 72.0 ± 9.3 years; 67(26.3%) were women. Forty one patients (16.1%) were asymptomatic; 214 patients (83.9%) were symptomatic. The patients in the asymptomatic group were significantly younger - 66.0 ± 8.8 years compared to patients in the symptomatic group 73.2 ± 8.9 years (p<0.0001). Intraprocedurally one minor stroke (2.4%) occurred in the asymptomatic group. At 30-day follow-up, no deaths or further strokes were noted in the asymptomatic group; while eight deaths, six major and seven minor strokes occurred in the symptomatic group (p=0.22).

Conclusion:

Carotid stenting appears to be a safe procedure in asymptomatic patients with severe carotid stenosis in routine clinical settings as witnessed in this single center study.

Carotid Revascularization: An Update

Symptomatic extracranial internal carotid artery stenosis poses a high short-time risk of ischemic cerebral stroke, as high as 20% to 30% in the first three months. Timely performed carotid endarterectomy (CEA) has been shown to be highly effective in reducing this risk although, in recent years, there has been great interest in replacing this procedure with less invasive carotid angioplasty and stenting (CAS). In this update we review recent studies and provide recommendations regarding the indications, methods and timing of surgical intervention as well as the anaesthetic management of CEA, and we report on recently published randomized controlled trials comparing CEA to CAS. We also provide recommendations regarding the sometime neglected but important medical management of patients undergoing carotid intervention, including antithrombotic and antihypertension therapy, lipid lowering agents, assistance with smoking cessation, and diabetes control.

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.

Cerebral hyperperfusion syndrome after endovascular reconstruction of carotid artery in high-flow carotid-jugular fistula

We describe the occurrence of cerebral hyperperfusion syndrome (CHS) in a case of long-standing carotid-jugular fistula (CJF) treated by endovascular reconstruction of the carotid artery. A 43-year-old male with a high-flow CJF between the internal carotid artery (ICA) and internal jugular vein underwent endovascular reconstruction of the carotid artery using a stent graft. After treatment, the patient developed CHS. The patient succumbed to a large intracranial bleed in the left external capsule and parietal lobe on the fifth postoperative day. CHS following endovascular reconstruction of carotid artery is rare. We present the first reported case of CHS following endovascular reconstruction of ICA. A review of literature for patients treated by endovascular rerouting of blood flow to the cerebral parenchyma associated with hyperperfusion syndrome has been performed.

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.

Seizures and the neurosurgical intensive care unit

The cause of seizures in the neurosurgical intensive care unit (NICU) can be categorized as emanating from either a primary brain pathology or from physiologic derangements of critical care illness. Patients are typically treated with parenteral antiepileptic drugs. For early onset ICU seizures that are easily controlled, data support limited treatment. Late seizures have a more ominous risk for subsequent epilepsy and should be treated for extended periods of time or indefinitely. This review ends by examining the treatment algorithms for simple seizures and status epilepticus and the role newer antiepileptic use can play in the NICU.