Hyperperfusion Syndrome after Carotid Endarterectomy

Seizures Following Carotid Endarterectomy: A Comprehensive Meta-Analysis of 69,479 Patients and Evidence-Based Recommendations for Perioperative Care

Background: Seizures are a rare but potentially serious complication following carotid endarterectomy (CEA). Understanding their prevalence and associated factors is crucial for optimizing perioperative care and improving patient outcomes. This meta-analysis aimed to estimate the pooled prevalence of seizures following CEA and explore clinical and procedural factors contributing to their occurrence. Methods: We conducted a systematic review and meta-analysis of studies reporting on seizures following CEA. A systematic search of PubMed, Embase, and Cochrane CENTRAL databases was performed, following PRISMA and MOOSE guidelines. Random-effects meta-analysis was used to calculate the pooled prevalence of postoperative seizures. Heterogeneity was assessed using the I2 statistic. A total of 20 studies, encompassing 69,479 patients, were included. Results: The overall pooled prevalence of seizures following CEA was 1% (95% CI: 0-2%; p < 0.001), with significant heterogeneity (I2 = 93.52%). Prospective studies reported a higher pooled prevalence (2%, 95% CI 0-4%; I2 = 76.34%) compared to retrospective studies (0%, 95% CI 0-1%; I2 = 91.51%). Male predominance was noted among patients who experienced seizures, and hypertension was the most common comorbidity. Cerebral hyperperfusion syndrome was identified as a key contributing factor to postoperative seizures. Data on long-term outcomes, including the development of epilepsy, were insufficient for further analysis. The methodological quality of the included studies varied, with most studies demonstrating a moderate risk of bias. Conclusions: Seizures occur in approximately 1% of patients following CEA, with higher rates observed in prospective studies. Cerebral hyperperfusion syndrome is an important contributor to this rare complication. We provide evidence-based specific recommendations for seizure management and introduce the SMART-CEA Checklist, a practical framework to guide perioperative care and reduce complications. Future research should focus on long-term outcomes, including epilepsy, and incorporate standardized methodologies to improve data reliability and guide clinical practice.

A Novel Endovascular Technique for Recanalization of Carotid Artery Chronic Total Occlusion: Staged Carotid Angioplasty and Stenting

AIM

Symptomatic carotid artery chronic total occlusion (SCACTO) can lead to neurocognitive function decline and carries a high risk or recurrent stroke. The treatment option is limited, endovascular intervention may be an alternative treatment but still controversial. To our knowledge, the staged carotid angioplasty and stenting (SCAS) did not previously reported. The purpose of this study was to report our experiences in this novel technique.

METHODS

In 2017-2018, we attempted the staged carotid angioplasty and stenting (SCAS) approach in 13 patients who received SCACTO treatment. The SCAS approach involves two stages of intervention. The first stage involves initial recanalization and initial small-sized balloon angioplasty. The second stage, which is performed 4-6 weeks later, involves angioplasty and carotid stent placement.

RESULTS

The success rate of SCAS was 76.9%. At the second stage, the lumen remained patent in all the patients. The mean spontaneous increase in lumen diameter after 4-6 weeks was 51.7%. The median length of the stent was 4.0 cm, and the median number of stents used was 1. One patient had a complication of dissection, with a complication rate of 7.6%.

CONCLUSIONS

SCAS is a novel technique in the endovascular treatment of SCACTO. It is a feasible and safe approach that could reduce the complication rate and number of carotid stents needed.

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.

Factors associated with the presence of postoperative headache in elective surgery patients: a prospective single center cohort study

PURPOSE

Headache is an important cause of minor postoperative morbidity. In this study we evaluated the association of anesthesia and surgery with the occurrence of postoperative headache in elective surgery patients.

METHODS

After obtaining ethical approval, 446 patients were enrolled in this prospective, single-centre cohort study. Participants were interviewed preoperatively, and for five days postoperatively, regarding the appearance of headache, while demographics, lifestyle, type of anesthesia and surgery, the anesthetic drugs administered and intraoperative adverse effects were recorded. Multiple logistic regression analysis was conducted in order to identify independent factors associated with postoperative headache, both in the total sample and in patients without previous history of headache.

RESULTS

The observed overall frequency of postoperative headache was 28.3% (N = 126) in the total sample. In patients with previous history of headache, the frequency of postoperative headache was 41% (N = 89), while in those with no history the frequency of postoperative headache was 16.2% (N = 37). Female gender [p = 0.024; odds ratio (OR) = 2.1], sevoflurane administration (p < 0.001; OR = 3.66), intraoperative hypotension (p = 0.008; OR = 2.12) and smoking (p = 0.006; OR = 1.74) were independently associated with postoperative headache. In patients without previous history, female gender (p = 0.005; OR = 4.77), sevoflurane administration (p = 0.001; OR = 6.9), intraoperative hypotension (p = 0.006; OR = 6.7) and caffeine consumption (p = 0.041; OR = 5.28) presented greater likelihood for postoperative headache, while smoking revealed no association.

CONCLUSION

Female gender, sevoflurane, smoking and intraoperative hypotension were documented as independent risk factors for postoperative headache. In patients with no previous history of headache, caffeine consumption was an additional independent factor for postoperative headache, while smoking revealed no association.

Insight into the cerebral hyperperfusion syndrome following carotid endarterectomy from the national Vascular Quality Initiative

BACKGROUND

Cerebral hyperperfusion syndrome (CHS), characterized by severe ipsilateral headache, seizures, and intracranial hemorrhage, is a rare, poorly understood complication that can be fatal following carotid endarterectomy (CEA). The purpose of the study was to determine the factors associated with CHS as captured in the Vascular Quality Initiative.

METHODS

Analysis was conducted on 51,001 procedures captured from the CEA module of the Vascular Quality Initiative from 2003 to 2015. Preoperative, operative, and postoperative variables were considered for inclusion in logistic regression analyses to determine possible associations with CHS. The relative contribution of each variable to the overall model was determined using dominance analysis.

RESULTS

The mean age was 70.2 ± 9.4 years; there were 39.6% female patients, 93.1% of white race, with 29.6% of CEAs being performed for symptomatic status. The overall rate of CHS was 0.18% (n = 94), with 55.1% occurring in asymptomatic and 44.9% occurring in symptomatic patients with an associated mortality rate of 38.2%. Multivariable analysis including preoperative variables showed that female gender (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.09-2.51; P = .019), <1 month major ipsilateral stroke (OR, 5.36; 95% CI, 2.35-12.22; P < .001), coronary artery disease (OR, 1.77; 95% CI, 1.15-2.71; P = .009), and contralateral stenosis ≥70% (OR, 1.54; 95% CI, 1.00-2.36; P = .050) were independently associated with CHS and that <1 month major stroke was the most important contributor to the model. With the additional inclusion of operative and postoperative variables, female gender (OR, 1.75; 95% CI, 1.14-2.67; P = .010), <1 month ipsilateral major stroke (OR, 3.20; 95% CI, 1.32-7.74; P = .010), urgency (OR, 2.25; 95% CI, 1.38-3.67; P = .001), re-exploration (OR, 2.98; 95% CI, 1.27-6.97; P = .012), postoperative hypertension (OR, 4.09; 95% CI, 2.65-6.32; P < .001), postoperative hypotension (OR, 3.21; 95% CI, 1.97-5.24; P < .001), dysrhythmias (OR, 3.23; 95% CI, 1.64-6.38; P = .001), and postoperative myocardial infarction (OR, 2.84; 95% CI, 1.21-6.67; P = .017) were significantly associated with CHS, with postoperative blood pressure lability and cardiac complications having the strongest associations with CHS.

CONCLUSIONS

The risk of CHS was highest in female patients and in those with a recent major stroke, coronary artery disease, and contralateral stenosis ≥70%. In addition, in adjusting for operative and postoperative variables, CHS was most significantly associated with postoperative blood pressure lability and cardiac complications. These data lend insight into a high-risk population for this devastating complication.

What Should We Do with Asymptomatic Carotid Stenosis?

The benefit of prophylactic carotid endarterectomy (CEA) for patients with asymptomatic severe carotid stenosis in the major randomised surgical studies was small, expensive and may now be absorbed by improvements in best practice medical intervention. Strategies to identify patients with high stroke risk are needed. If surgical intervention is to be considered the complication rates of individual surgeons should be available. Clinicians will differ in their interpretation of the same published data. Maintaining professional relationships with clinicians from different disciplines often involves compromise. As such, the management of a patient will, in part, depend on what kind of specialist the patient is referred to. The clinician's discussion with patients about this complex issue must be flexible to accommodate differing patient expectations. Ideally, patients prepared to undergo surgical procedures should be monitored in a trial setting or as part of an audited review process to increase our understanding of current practice outcomes.

Global oxygen extraction fraction by blood sampling to anticipate cerebral hyperperfusion phenomenon after carotid artery stenting

BACKGROUND

Cerebral hyperperfusion syndrome sometimes occurs after carotid revascularization in patients with severe hemodynamic failure. To prevent cerebral hyperperfusion syndrome, cerebral hyperperfusion phenomenon (CHP) must be detected early. Single-photon emission computed tomography (SPECT) is useful for detecting CHP, but it is impractical on a daily basis. A tool with high availability to find CHP is desired.

OBJECTIVE

To investigate whether global oxygen extraction fraction (OEF) by a blood sampling method is useful for indicating CHP after carotid artery stenting (CAS).

METHODS

When patients underwent elective CAS from September 2010 to August 2012, we performed blood sampling for OEF calculation and SPECT before and immediately after elective CAS. Data were collected prospectively. OEF was calculated from the cerebral arteriovenous oxygen difference. Cerebral blood flow was measured in the affected middle cerebral artery (MCA) territory and in the ipsilateral cerebellum by SPECT. The ratio of MCA to cerebellar activity was defined as cerebral blood flow in the affected MCA territory divided by cerebral blood flow in the ipsilateral cerebellar hemisphere. Probable CHP was defined as ≥10% increase in the ratio of MCA to cerebellar activity after CAS. The relationship between peri-CAS OEF and probable CHP was evaluated.

RESULTS

Of the 96 patients enrolled, 92 patients were analyzed. Probable CHP occurred in 17 patients. Post-CAS OEF was related to probable CHP (P < .01), but pre-CAS OEF was not. The receiver-operating characteristic curve showed that the cutoff value was 45% for probable CHP (P < .001).

CONCLUSION

An increase in blood sampling OEF immediately after CAS was related to probable CHP; then the oxygen demand should be reduced.

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.

[Delayed post-operative epileptic seizure after carotid endarterectomy: a case of cerebral hyperperfusion syndrome?]

The so-called cerebral hyperperfusion syndrome is basically due to a lack of cerebral autoregulation, inability to control the restoring of flow after revascularisation surgery. It present clinically as intense migraine, epileptic seizures, or neurological focality. It may even progress to an intracerebral haemorrhage. It usually appears a few days after surgery. We present the case of a patient subjected to a carotid endarterectomy, who had an epileptic episode in the late post-operative period. We attributed a cerebral hyperperfusion syndrome as the most likely cause. Knowledge of this syndrome may help to correctly orientate and treat the neurological complications that appear after this type of surgery.

Cerebral hyperperfusion syndrome after carotid intervention: a review

Cerebral hyperperfusion syndrome (CHS) after carotid surgery, although rare, is a well-described phenomenon. Although originally described after carotid endarterectomy, it has now also been described after carotid artery stenting. It is classically described as an acute neurologic deficit occurring several days after a carotid procedure, associated with severe hypertension and preceded by a severe headache. CHS represents a spectrum of clinical symptoms ranging from severe unilateral headache, to seizures and focal neurologic defects, to intracerebral hemorrhage in its most severe form. The exact mechanism leading to CHS is unknown; however, it seems to be related to increased regional cerebral blood flow secondary to loss of cerebrovascular autoregulation. Given the significant morbidity associated with CHS, researchers have been trying to identify which patients are most at risk. This is a difficult task given the rarity of the disease and the multiple confounding factors in the patient population who undergo carotid intervention. The goal was to determine those patients most at risk preoperatively, so that they may be more closely monitored postoperatively to prevent the development of CHS and its associated morbidity. The purpose of this review was to summarize the data currently available in the literature on CHS, with emphasis on pathophysiology, risk factor assessment, diagnostic modalities, and disease management, to provide insight for future research to better elucidate how to reduce the morbidity and mortality caused by CHS.

Hypertension and the post-carotid endarterectomy cerebral hyperperfusion syndrome

OBJECTIVE

Cerebral hyperperfusion syndrome is a preventable cause of stroke after carotid endarterectomy (CEA). It manifests as headache, seizures, hemiparesis or coma due to raised intracranial pressure or intracerebral haemorrhage (ICH). There is currently no consensus on whether to control blood pressure, blood pressure thresholds associated with cerebral hyperperfusion syndrome, choice of anti-hypertensive agent(s) or duration of treatment.

METHOD

A systematic review of the PubMed database (1963-2010) was performed using appropriate search terms according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 36 studies were identified as fitting a priori inclusion criteria. Following CEA, the incidence of severe hypertension was 19%, that of cerebral hyperperfusion 1% and ICH 0.5%. The postoperative mean systolic blood pressure of patients, who went on to develop cerebral hyperperfusion syndrome, was 164 mmHg (95% confidence interval (CI) 150-178 mmHg) and the cumulative incidence of cases rose appreciably above a postoperative systolic blood pressure of 150 mmHg. The mean systolic blood pressure of cerebral hyperperfusion cases was 189 mmHg (95% CI 183-196 mmHg) at presentation. The incidence of cerebral hyperperfusion in the first week was 92% with a median time to presentation of 5 days (interquartile range (IQR) 3-6 days). 36% of patients presented with seizures 31% with hemiparesis and 33% with both. The proportion of patients with severe hypertension was significantly higher in cases than in post-CEA controls (p < 0.0001, Odds ratio 19 (95% CI 9-41)). Three large case-control studies identify postoperative hypertension as a risk factor for ICH.

CONCLUSION

There is currently level-3 evidence for the prevention of ICH through control of postoperative blood pressure. From the available data, we suggest a definition for cerebral hyperperfusion syndrome, blood pressure thresholds, duration of monitoring and a postoperative blood pressure control strategy for validation in a prospective study. The implications of this are that one in five patients would need intravenous anti-hypertensives and home blood pressure monitoring for 1 week.

Predictors of cerebral reperfusion injury after carotid stenting: the role of transcranial color-coded Doppler ultrasonography

PURPOSE

To evaluate the possible role of transcranial color-coded Doppler ultrasonography (TCD) in predicting cerebral reperfusion injury (CRI) in patients undergoing carotid artery stenting (CAS) for internal carotid artery (ICA) stenosis.

METHODS

TCD was obtained in 210 patients (149 men; mean age 64.2+/-8.4 years, range 44-83) who underwent CAS for ICA stenosis averaging 86.7%+/-8.4%. Contralateral ICA occlusion or near occlusion (stenosis >90%) was present in 67 (31.9%) patients. TCD was performed before and 24 hours after CAS with assessment of peak systolic velocities (PSVs) in the ipsilateral middle cerebral artery (iMCA) and contralateral middle cerebral artery (cMCA). PSV ratios (PSVR) in the iMCA and cMCA were calculated from the PSVs before and after CAS.

RESULTS

CRI syndrome occurred in 3 (1.4%) patients (2 intracranial bleedings, 1 subarachnoid hemorrhage). The mean iMCA and cMCA PSVRs were 2.66+/-0.19 and 4.16+/-2.77, respectively, in CRI patients, while the PSVRs in CAS patients without neurological sequelae were 1.56+/-0.46 and 1.21+/-0.39, respectively (both p<0.001). The combination of iPSVR>2.4 and cPSVR>2.4 occurred in 4 patients with bilateral ICA disease; 3 (75%) of them developed CRI (100% sensitivity and 99% specificity for CRI prediction). The following independent CRI predictors were identified: combined iPSVR>2.4 and cPSVR>2.4 (RR 2.06, CI 1.89 to 2.24; p<0.001), high cMCA PSV after CAS (RR 1.23, CI 1.13 to 1.34; p<0.001), and contralateral ICA occlusion (RR 1.13, CI 1.03 to 1.23; p = 0.007).

CONCLUSION

TCD is an important tool in CRI risk evaluation. The combination of iPSVR>2.4 and cPSVR>2.4 is an independent CRI risk factor, along with contralateral ICA occlusion and high cMCA PSVs after CAS.

Hyperperfusion syndrome after carotid revascularization

Cerebral hyperperfusion syndrome is a rare, serious complication of carotid revascularization either after carotid endarterectomy or carotid stent placement. Impaired cerebral autoregulation and post-revascularization changes in cerebral hemodynamics are the main mechanisms involved in the development of the syndrome. Hyperperfusion syndrome may be fatal once an intracranial hemorrhage occurs. This article reviews the literature, intending to make a synthesis of all new data concerning the clinical manifestations of hyperperfusion syndrome, the pathophysiologic pathways involved in its development, the prediction, and the appropriate management. Also, a review of the most recent series of hyperperfusion syndrome following carotid revascularization, both with classic open endarterectomy and carotid artery stenting has been performed.

Arterial spin-labeling in routine clinical practice, part 3: hyperperfusion patterns

Arterial spin-labeled (ASL) perfusion imaging can be implemented successfully into a routine clinical neuroimaging protocol and can accurately demonstrate alterations in brain perfusion. We have observed patterns of focal, regional, and global hyperperfusion in a wide variety of disease processes. The causes of hyperperfusion at clinical ASL have not been previously characterized. Focal lesions such as brain tumors and vascular malformations with increased perfusion can be well depicted by ASL. More global causes of hyperperfusion, including postanoxia vasodilation and hypercapnia, may go undetected on conventional MR images, whereas the regional hyperperfusion, which may occur in reversible encephalopathies and luxury perfusion, has been consistently illustrated on ASL cerebral blood flow maps at our institution.

Arterial spin-labeling in routine clinical practice, part 2: hypoperfusion patterns

Arterial spin-labeling (ASL) is a powerful perfusion imaging technique capable of quickly demonstrating both hypo- and hyperperfusion on a global or localized scale in a wide range of disease states. Knowledge of pathophysiologic changes in blood flow and common artifacts inherent to the sequence allows accurate interpretation of ASL when performed as part of a routine clinical imaging protocol. Patterns of hypoperfusion encountered during routine application of ASL perfusion imaging in a large clinical population have not been described. The objective of this review article is to illustrate our experience with a heterogeneous collection of ASL perfusion cases and describe patterns of hypoperfusion. During a period of 1 year, more than 3000 pulsed ASL procedures were performed as a component of routine clinical brain MR imaging evaluation at both 1.5 and 3T. These images were reviewed with respect to image quality and patterns of hypoperfusion in various normal and disease states.

Intracranial stenting of severe symptomatic intracranial stenosis: results of 100 consecutive patients

BACKGROUND AND PURPOSE

There are a few reports regarding the outcome evaluation of balloon-expandable intracranial stent placement (BEICS). The purpose of our study was to evaluate the outcome and factors related to the adverse events (AEs) of BEICS.

MATERIALS AND METHODS

We evaluated 100 consecutive patients who underwent BEICS. We assessed the procedural success (residual stenosis < 50%), AEs (minor strokes, major strokes, and death), clinical outcome, and restenosis (> 50%) at 6 months. We also analyzed 18 factors including symptom patterns related to AE rate. Symptom patterns revealed 1) stable patients (n = 73) with improving, stationary, or resolved symptoms; and 2) unstable patients (n = 27) with gradual worsening or fluctuating symptoms (National Institutes of Health Stroke Scale [NIHSS] > or = 4) within 2 days before stent placement.

RESULTS

The procedural success rate was 99%. Overall, there were 10 (10%) AEs within the 6 months: 4 (4%) minor strokes, 3 (3%) major strokes, and 3 (3%) deaths including a death from myocardial infarction. AE rate was 4.1% in stable and 25.9% in unstable patients. Restenosis at 6 months revealed 0% (0/59). Good outcome (modified Rankin Scale < or = 2) at 6 months was 97% (71/73) in stable and 67% (18/27) in unstable patients. Stepwise logistic regression model revealed that symptom pattern (unstable versus stable) was the only significant risk factor (OR, 8.167; 95% CI, 1.933-34.500; P = .004).

CONCLUSION

BEICS revealed a low AE and good outcome rate at 6 months, especially in the stable patients. Midterm outcome was also favorable in the unstable patient group.

Subarachnoid hemorrhage after carotid artery stenting

We describe subarachnoid hemorrhage (SAH) in a 66-year-old man, who underwent technically successful carotid stenting for a string-stenosis of the right internal carotid artery (ICA) in a presence of contralateral ICA occlusion with recurrent right hemisphere transient ischemic attacks. At 2 hours, the patient developed headache and vomiting, but no focal neurological deficits. Performed transcranial color-coded Doppler (TCCD) showed over 2.8-fold increase of the peak systolic velocity in the right middle cerebral artery. The emergent CT of the brain showed SAH with the right hemisphere edema. Patient was treated with Nimodipine in continuous infusion, diuretics i.v. and additional hypotensive therapy depending on blood pressure values. Clopidogrel was stopped for 5 days. Over next 4 weeks, a gradual cerebral velocities decrease was observed on TCCD, which was related to clinical and CT resolution.

Risk Estimates of Stroke After Coronary Artery Bypass Graft and Carotid Endarterectomy

Neurologic complications of cardiovascular surgeries are well documented in the literature. Neurologic deficits may be mild and reversible or may be associated with permanent neurologic deficit. The incidence and severity of such complications vary according to the type of surgical procedure and usually correlate with patients' preoperative general medical condition, duration of surgeries, and intraoperative complications.

Assessment of Flow Changes in the Circle of Willis After Stenting for Severe Internal Carotid Artery Stenosis

PURPOSE

To assess flow velocities in the cerebral arteries after carotid artery stenting (CAS) in patients with unilateral versus bilateral lesions and analyze velocities in patients with neurological complications after CAS.

METHODS

Ninety-two patients (68 men; mean age 63.2 +/- 8.4 years, range 44-82) with internal carotid artery (ICA) stenoses were divided according to unilateral (group I, n = 72) or bilateral (group II, n = 20) disease. Fifty age- and gender-matched patients without lesions in the extra- or intracranial arteries served as a control group. Transcranial color-coded Doppler ultrasound was performed prior to and within 24 hours after CAS in the test groups; systolic velocities were assessed ipsilateral (i) and contralateral (c) to the CAS site in the middle cerebral artery (MCA) and anterior cerebral artery (ACA).

RESULTS

Collateral flow via the anterior communicating artery (ACoA) was found in all group-II patients and 90% of group-I patients. After CAS, collateral flow through the ACoA ceased, and the velocity increased by 26% in the iMCA in group I compared to controls (p < 0.001). In group II, iMCA flow increased by 30% (p < 0.001) and flow via the ACoA (p < 0.001) increased, resulting in normalization of cMCA velocities (p = 0.928). In 89 (96.7%) subjects, CAS was uncomplicated. Hyperperfusion syndrome occurred in 2 (2.2%) patients, both with bilateral ICA stenoses; 1 (1.1%) transient ischemic attack was seen in a patient with unilateral disease. In the patients with hyperperfusion syndrome, the MCA velocities were 2.7- and 7.4-fold higher, respectively, versus before CAS and 2-fold higher than in controls.

CONCLUSION

Uncomplicated CAS results in an iMCA velocity increase >25% compared to controls. MCA velocities in hyperperfusion syndrome were greatly increased versus before CAS and in controls.

Cerebral hyperperfusion syndrome

Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy is characterised by ipsilateral headache, hypertension, seizures, and focal neurological deficits. If not treated properly it can result in severe brain oedema, intracerebral or subarachnoid haemorrhage, and death. Knowledge of CHS among physicians is limited. Most studies report incidences of CHS of 0-3% after carotid endarterectomy. CHS is most common in patients with increases of more than 100% in perfusion compared with baseline after carotid endarterectomy and is rare in patients with increases in perfusion less than 100% compared with baseline. The most important risk factors in CHS are diminished cerebrovascular reserve, postoperative hypertension, and hyperperfusion lasting more than several hours after carotid endarterectomy. Impaired autoregulation as a result of endothelial dysfunction mediated by generation of free oxygen radicals is implicated in the pathogenesis of CHS. Treatment strategies are directed towards regulation of blood pressure and limitation of rises in cerebral perfusion. Complete recovery happens in mild cases, but disability and death can occur in more severe cases. More information about CHS and early institution of adequate treatment are of paramount importance in order to prevent these potentially severe complications.