Comparison of microembolism detected by transcranial Doppler and neuropsychological sequelae of carotid surgery and percutaneous transluminal angioplasty

Postoperative neurocognitive function and microembolus detection in patients undergoing neck dissection: a pilot study

BACKGROUND AND OBJECTIVE

Patients undergoing oncologic neck dissection may have many of the risk factors for carotid artery stenosis, thus predisposing them to perioperative cerebral ischaemic events. The present study was designed to investigate development of postoperative neurocognitive dysfunction in these patients.

METHODS

Twenty-six patients were assessed the day before surgery and 48 h and 12 months after surgery using a comprehensive neuropsychological test battery. Cognitive performance was compared with a matched control group to account for the practise effect associated with repeated testing. Doppler ultrasonography was used to detect intraoperative cerebral microembolism. S100beta protein values were evaluated before and immediately after anaesthesia.

RESULTS

On the second postoperative day, 26.9% of patients undergoing neck dissection had postoperative neurocognitive deficit (POCD), defined as a total deficit score of 2SD worse than the mean performance in the control group. Microemboli were found only in the neck dissection group. S100beta levels were significantly higher after neck dissection (Wilcoxon signed ranked test: P<0.001). After 12 months, the incidence of POCD was similar in both groups.

CONCLUSION

POCD was detectable only after neck dissection in the early postoperative period accompanied by increased incidence of microembolism and protein S100beta levels, but not 12 months after surgery.

Classification for carotid artery stenting complications: manifestation, management, and prevention

Carotid artery stenting is a rapidly evolving method for treating carotid artery disease. Various intraprocedural and postprocedural complications have been reported in the literature. However, the absence of a unified classification scheme for these complications makes it difficult, if not impossible, to study their precise incidence, predictors, and management. The aim of this article is to propose the first joint classification of periprocedural complications, to analyze their incidence and etiology, and suggest possible ways to manage and prevent them. This classification is intended to be used as a common platform for prompt recognition, evaluation, treatment, and universal study of the complications during carotid stenting procedures. For this purpose, the opinions of the major experts on carotid interventions worldwide were merged with all the available information reported in the English-language literature to present as accurately as possible the management and prevention of carotid stenting complications according to this proposed classification.

Outcomes of Carotid Artery Stenting in High-Risk Patients With Carotid Artery Stenosis

OBJECTIVE

Carotid artery angioplasty and carotid artery stenting (CAS) offer a viable alternative to carotid endarterectomy for symptomatic and asymptomatic patients; however, the complication rates associated with CAS may be higher than previously documented. We evaluated the safety and efficacy of CAS in high surgical risk patients in a single neurovascular center retrospective review.

METHODS

An institutional review board–approved retrospective review of the clinical variables and treatment outcomes of 101 consecutive patients (109 stents) from July 2001 to March 2007 with carotid stenosis were analyzed. Both symptomatic and asymptomatic stenoses were studied in high surgical risk patients as defined by the SAPPHIRE (Stenting and Angioplasty with Protection in Patients at High-Risk for Endarterectomy) trial. Specifically, those patients with clinically significant cardiac disease (congestive heart failure, abnormal stress test, or need for open-heart surgery), severe pulmonary disease, contralateral carotid occlusion, contralateral laryngeal nerve palsy, recurrent stenosis after carotid endarterectomy, previous radical neck surgery, or radiation therapy to the neck, and an age older than 80.

RESULTS

Seventy-four percent of the patients were symptomatic (n = 81), and the mean stenosis in symptomatic patients was 83%. Reasons for stenting included cardiac/pulmonary/medical risk (60%), contralateral internal carotid artery occlusion (8%), recurrent stenosis after carotid endarterectomy (11%), carotid dissection (6%), age older than 80 (7%), previous radical neck surgery (7%), and previous neck radiation (1%). Stent deployment was achieved in 108 of 109 vessels (99%). Distal embolic protection devices were used in 72% of cases treated. The overall rate of in-hospital adverse events (transient ischemic attack, intracranial hemorrhage, minor stroke, major stroke, myocardial infarction, and death) was 8.3% (9 of 109). Of these events, 2 patients (1.8%) experienced a hemispheric transient ischemic attack (neurological symptoms that resolved within 24 hours), 2 others (1.8%) had transiently symptomatic acute reperfusion syndrome. The 30-day stroke/death/myocardial infarction risk was 4.6% (n = 5). Of these patients, 3 had minor strokes (2.7%) defined as a modified Rankin Scale score less than 3 at 1-year follow-up, 1 had a major stroke (0.9%) defined as a modified Rankin Scale score of 3 or more at 1-year follow-up, and 1 patient died after a periprocedural myocardial infarction (0.9%).

CONCLUSION

CAS can be performed with a low 30-day complication rate, even with a higher percentage of symptomatic lesions. The results support the use of CAS in high surgical risk patients with both significant symptomatic and asymptomatic carotid artery disease.

Incidence of moderate to severe cognitive dysfunction in patients treated with carotid artery stenting

OBJECTIVE

Approximately 25% of patients with carotid artery stenosis treated with carotid endarterectomy develop cognitive dysfunction (CD) between 1 day and 1 month after surgery compared with a control group. We hypothesized that patients with carotid artery stenosis treated with carotid artery stenting (CAS) performed under cerebral embolic protection also develop CD at similar time points compared with a control group.

METHODS

Twenty-four patients scheduled for elective CAS were enrolled in a prospective institutional review board-approved study to evaluate cognitive function with a battery of 6 neuropsychometric tests before, and 1 day and 1 month after, CAS. Test performance was compared with 23 patients undergoing coronary artery procedures (control group). The mean and standard deviation of the difference scores in the control group were used to generate Z scores. We used a previously described point system to transform negative Z scores into injury points for each neuropsychometric test. Global performance is presented as average deficit score (sum of injury points divided by the number of completed tests). All patients underwent the procedures with mild sedation. Results were analyzed in 2 ways: group-rate and event-rate analysis. Outcome was dichotomized by defining moderate to severe CD as average deficit score at least 1.5 standard deviations worse than the control group. Fisher tests and multivariate logistic regression models were used to analyze group performance.

RESULTS

Control patients tended to be younger and had a lower incidence of stroke or previous transient ischemic attack. One day after surgery, 41% of patients (10 of 24) treated with CAS developed moderate to severe CD (P = 0.0422). Average deficit score was also significantly higher in the CAS group at 1 day (P = 0.0265). These differences were independent of age and history of stroke/transient ischemic attack. Interestingly, we found that the absence of oral statin medication may increase the probability of CD. By 1 month, 9% of patients (1 of 11) treated with CAS presented with CD. Other patients were lost to follow-up.

CONCLUSION

CAS is associated with a decline in cognitive performance that is at least moderate 1 day after surgery.

Neuropsychological sequelae of carotid angioplasty with stent placement: correlation with ischemic lesions in diffusion weighted imaging

Background and Purpose

Few studies investigated the neuropsychological outcome after carotid angioplasty with stent placement (CAS), yielding partially inconsistent results. The present investigation evaluated the effect of CAS in patients with high-grade stenosis and assessed the predictive value of ischemic lesion number for postinterventional cognitive deterioration.

Methods

22 patients were tested neuropsychologically before and six weeks after CAS. Cerebral ischemic changes were assessed with diffusion weighted imaging (DWI) prior to and after angioplasty.

Results

Pre- to postinterventional cognitive performance improved significantly in terms of verbal memory (t = −2.30; p<0.05), whereas significant deterioration was noted regarding verbal memory span (t = 2.31; p<0.05). 8 (36%) persons conformed to the criteria of cognitive improvement. 6 patients (27%) were postinterventionally classified as having deficits. Analysis yielded no statistically significant correlations between lesion quantity and cognitive change.

Conclusion

Both improvement and deterioration of cognitive functioning was observed in our collective of patients, leaving the neuropsychological outcome after percutaneous transluminal angioplasty unpredictable in individual cases. The presence of acute ischemic lesions on DWI was found to be not tightly associated with cognitive dysfunction after CAS.

Volume and composition of emboli in neuroprotected stenting of the carotid artery

BACKGROUND AND PURPOSE

Periprocedural microembolization is a major and permanent risk for patients treated by angioplasty and stent placement of high-grade carotid stenoses. Little is known however about the characteristics and significance of these embolized particles. Our aim was to assess the volume and composition of debris captured by filters during carotid angioplasty and stent placement (CAS) of severe internal carotid artery (ICA) stenoses.

MATERIALS AND METHODS

Institutional review board approval and informed consent from all subjects were obtained. Two hundred one patients (mean age, 66.2 years; range, 35-82 years) with > or = 70% stenosis of the ICA underwent filter-protected CAS. Ultrastructural and semiquantitative analysis of the volume of filters was obtained. Multifactorial statistical analysis was performed to determine factors related to debris volume and composition.

RESULTS

Transient ischemic attack occurred in 6 patients (3%), and a major stroke, in 1 (0.5%). Debris was found in 117 filters (58.2%), with volume <1 lambda (0.001 mL) in 71%. The number of balloon dilations, age older than 65 years, and calcified plaques in pre-CAS angiography were significantly associated with the presence of particulates inside the filters (P < .03, P < .004, and P < .05, respectively).

CONCLUSIONS

Vessel wall and atheromatous plaques are the main source of microemboli during CAS. Embolization is mainly related to the number of balloon dilations during CAS. Planning a proper and individualized strategy for the procedure in each patient is essential to minimize the potential effects of manipulation during CAS.

The effect of severe carotid occlusive disease and its surgical treatment on cognitive functions of the brain

Surgery of a high-grade carotid stenosis is evidence-based stroke prevention. Also cognitive effects are reported after carotid endarterectomy (CEA): both deterioration and improvement, the former attributed to perioperative complications and the latter often to learning effect. By imaging, brain perfusion and diffusion changes were shown in subjects with a high-grade stenosis undergoing CEA. We wanted to find out if the cognition of patients undergoing CEA display postoperative worsening or true improvement in association with findings in serial MR imaging. The patients had a poorer overall cognition than healthy matched controls. The cerebral hemisphere ipsilateral to the stenosis had higher diffusion and more sluggish perfusion leading to perfusion deficits. These asymmetries were abolished by CEA. Postoperatively, the patients showed a trend for cognitive worsening, most often attentional, but over months, the group performance improved similarly to the controls. Still, lower baseline perfusion was associated with a greater cognitive improvement, most clearly in executive functions. Consequently, despite the risk for transient decline, true cognitive benefit by CEA seems possible.

Intraoperative cerebral high-intensity transient signals and postoperative cognitive function: a systematic review

BACKGROUND

Much attention in the literature has focused on the relationship between perioperative microemboli during cardiac and vascular surgery and postoperative cognitive decline. Transcranial Doppler ultrasonography (TCD) has been used to measure high-intensity transient signals (HITS), which represent microemboli during cardiac, vascular, and orthopedic surgery. The purpose of this study was to systematically examine the literature with respect to HITS and postoperative cognitive function.

METHODS

Systematic PubMed searches identified articles related to the use of TCD and cognitive function in the surgical setting.

RESULTS

The literature remains largely undecided on the role of HITS and cognitive impairment after surgery, with most studies being underpowered to show a relationship. Although the cognitive effects of HITS may be difficult to detect, subclinical microemboli present potential harm, which may be modifiable.

CONCLUSIONS

TCD represents a tool for intraoperative cerebral monitoring to reduce the number of HITS during surgery.

Frequency of thromboembolic events associated with endovascular aneurysm treatment: retrospective case series

Object

There is little evidence addressing whether procedures requiring adjunctive devices lead to an increased frequency of thromboembolic complications. The authors report their experience with 155 aneurysms treated with and without adjunctive devices.

Methods

The authors retrospectively reviewed their last 155 aneurysm coil placement procedures. The patients' records were reviewed for the following phenomena: 1) evidence of procedure-related thrombus formation; 2) clinical evidence of stroke; and 3) the presence of acute ischemia in the treated vascular territory on diffusion-weighted (DW) imaging.

Results

Of the 155 aneurysms treated in 132 patients, 66 were treated with coils only, 45 had stent-assisted coil placement, 33 underwent balloon remodeling, and in 11 stents were placed after balloon remodeling. Small DW imaging abnormalities were present in the treated vascular territory in 24% of cases (37 lesions). Specifically, 21 (32%) of 66 lesions in the coil-treated group, 6 (13%) of 45 in the stent-assisted coil treatment group, 8 (24%) of 33 in the balloon remodeling group, and 2 (18%) of 11 in the balloon and stent group showed DW imaging positivity. Furthermore, 25 (68%) of the 37 cases that were positive on DW imaging occurred in patients presenting with subarachnoid hemorrhage (SAH). Clinically evident stroke or transient ischemic attack was present in 10 (27%) of 37 cases, with 70% occurring in patients presenting with SAH.

Conclusions

Use of adjunctive devices in treating aneurysms does not appear to increase the frequency of embolic or ischemic events. The presence of DW imaging abnormalities and clinically evident stroke was actually less frequent when adjunctive devices were used and in electively treated cases. This was probably related to perioperative antiplatelet medical management.

Strategies for conditional two-locus nonparametric linkage analysis

In this article we deal with two-locus nonparametric linkage (NPL) analysis, mainly in the context of conditional analysis. This means that one incorporates single-locus analysis information through conditioning when performing a two-locus analysis. Here we describe different strategies for using this approach. Cox et al. [Nat Genet 1999;21:213-215] implemented this as follows: (i) Calculate the one-locus NPL process over the included genome region(s). (ii) Weight the individual pedigree NPL scores using a weighting function depending on the NPL scores for the corresponding pedigrees at speci fi c conditioning loci. We generalize this by conditioning with respect to the inheritance vector rather than the NPL score and by separating between the case of known (prede fi ned) and unknown (estimated) conditioning loci. In the latter case we choose conditioning locus, or loci, according to prede fi ned criteria. The most general approach results in a random number of selected loci, depending on the results from the previous one-locus analysis. Major topics in this article include discussions on optimal score functions with respect to the noncentrality parameter (NCP), and how to calculate adequate p values and perform power calculations. We also discuss issues related to multiple tests which arise from the two-step procedure with several conditioning loci as well as from the genome-wide tests.

COGNITIVE OUTCOMES AFTER CAROTID REVASCULARIZATION

OBJECTIVE

Carotid artery stenting (CAS) and carotid endarterectomy (CEA) are currently being compared in ongoing randomized, controlled trials using postprocedural 30-day stroke rate, myocardial infarction, and mortality as primary endpoints. Recent data suggest that cognitive function may decline after CEA. Understanding the mechanisms that affect cognitive outcomes after carotid revascularization will be important in the design of future comparative studies of CAS and CEA incorporating cognitive outcome as an endpoint.

SUMMARY OF REVIEW

The effects of carotid revascularization procedures on cognitive outcome are unclear. Several factors contribute to the difficulty in interpreting cognitive data, including patient heterogeneity, variability of surgical techniques, and the differences in neuropsychological testing methodology. Mechanisms underlying cognitive effects during CEA have emerged, including the potential detrimental effect of procedural emboli and the beneficial effect of improved cerebral hemodynamics. The emergence of CAS as an alternative to CEA for treating carotid stenosis again raises questions about cognitive outcomes. Despite the use of distal protection devices, CAS is associated with a higher burden of microemboli. CAS does not, however, require the extent of temporary vessel occlusion associated with CEA. Quantifying microemboli and changes in cerebral hemodynamics along with standardization of neuropsychological testing may lead to meaningful comparisons of cognitive data for patients undergoing carotid revascularization procedures.

CONCLUSION

As use of CAS increases, it is important for randomized, controlled trials comparing CAS with CEA to include cognitive outcomes assessments. Furthermore, understanding the key mechanisms resulting in cognitive impairment during carotid revascularization procedures might limit injury.

Chronic ischemia and neurocognition

Cognitive impairment from a major stroke as a consequence of carotid disease is an acknowledged clinical outcome; however, cognitive impairment without major stroke is open to discussion. The three recognized mechanisms for cognitive dysfunction from internal carotid artery are microembolization, white-matter disease, and hypoperfusion. The last has been most difficult to characterize physiologically. In this article, the authors review evidence supporting the existence of chronic ischemia in the brain and its direct impact on cognitive functions. By incorporating the pathophysiology of chronic ischemia into the algorithm of the management of carotid artery disease, we may be able to extend the goals of carotid artery revascularization beyond merely preventing stroke to include preventing or reversing cognitive decline.

Neurocognitive changes after carotid revascularization: a review of the current literature

OBJECTIVE

The objective of this study was to review the current literature evaluating the effect of carotid revascularization on neurocognitive function.

METHODS

A PubMed search was performed using the following keywords: carotid surgery, carotid stenosis, cognition, and cognition disorders. Bibliographies were cross referenced and related-articles searches were performed once an article of interest had been identified.

RESULTS

Twenty-two studies have been identified from the literature since 1998. Seventeen articles evaluated carotid endarterectomy (CEA), four evaluated carotid stenting, and one compared CEA to stenting. Eight studies found improvements in mood and/or cognition after revascularization, 11 studies showed mixed results, and 3 studies found declines.

CONCLUSIONS

There is no consensus within the current literature as to the effect of carotid revascularization on neurocognitive function. Further research--with attention to laterality of neurocognitive effects, patients' symptomatology at the time of presentation, the role of perioperative embolization, and trial design including adequate control groups and comparison between open surgery and stenting factors--is necessary in order to clarify the effects of carotid revascularization on cognition.

Neuropsychological consequences of endarterectomy and endovascular angioplasty with stent placement for treatment of symptomatic carotid stenosis: a prospective randomised study

BACKGROUND AND PURPOSE

Previous studies compared carotid endarterectomy (CEA) and carotid artery stent placement (CAS) for treatment of symptomatic carotid artery stenosis. Whereas most previous studies showed both treatment modalities to be associated with a comparable risk of periprocedural cerebrovascular complications, these previous studies have shown significantly more microemboli and significantly more lesions in diffusion-weighted MR imaging after CAS compared to CEA. The clinical relevance of these differences remains unknown. We therefore compared the neuropsychological consequences of CAS and CEA and additionally measured the S100beta protein, a marker of cerebral damage.

METHODS

A total of 48 patients with symptomatic carotid artery stenosis greater than 70 % (according to ECST criteria) were enrolled and 45 patients participated in the follow-up. The patients were randomly assigned for CEA (24 patients) or CAS (21 patients). S100beta protein values were evaluated 2 hours before the procedure, as well as one and two hours thereafter. Patients were assessed before treatment, and again 6 and 30 days after treatment using a comprehensive neuropsychological test battery.

RESULTS

Patients of the CAS and the CEA groups did not significantly differ in terms of age, gender, education, degree of carotid artery stenosis, cerebrovascular symptoms and vascular risk factors. Following previously used criteria, a cognitive change in patients was assumed to have occurred when there was a decline of more than one standard deviation in two or more tests assessing various cognitive domains. Six days and 30 days after the treatment both groups showed a comparable number of patients with cognitive changes compared to baseline. There were no significant differences in S100beta protein values.

CONCLUSION

These results provide some reassurance that CAS is not associated with greater cognitive deterioration than CEA is.

Significance of postoperative crossed cerebellar hypoperfusion in patients with cerebral hyperperfusion following carotid endarterectomy: SPECT study

PURPOSE

Cerebral hyperperfusion after carotid endarterectomy (CEA) results in cerebral hyperperfusion syndrome and cognitive impairment. The goal of the present study was to clarify the clinical significance of postoperative crossed cerebellar hypoperfusion (CCH) in patients with cerebral hyperperfusion after CEA by assessing brain perfusion with single-photon emission computed tomography (SPECT).

METHODS

Brain perfusion was quantitatively measured using SPECT and the [(123)I]N-isopropyl-p-iodoamphetamine-autoradiography method before and immediately after CEA and on the third postoperative day in 80 patients with ipsilateral internal carotid artery stenosis (>or=70%). Postoperative CCH was determined by differences between asymmetry of perfusion in bilateral cerebellar hemispheres before and after CEA. Neuropsychological testing was also performed preoperatively and at the first postoperative month.

RESULTS

Eleven patients developed cerebral hyperperfusion (cerebral blood flow increase of >or=100% compared with preoperative values) on SPECT imaging performed immediately after CEA. In seven of these patients, CCH was observed on the third postoperative day. All three patients with hyperperfusion syndrome exhibited cerebral hyperperfusion and CCH on the third postoperative day and developed postoperative cognitive impairment. Of the eight patients with asymptomatic hyperperfusion, four exhibited CCH despite resolution of cerebral hyperperfusion on the third postoperative day, and three of these patients experienced postoperative cognitive impairment. In contrast, four patients without postoperative CCH did not experience postoperative cognitive impairment.

CONCLUSIONS

The presence of postoperative CCH with concomitant cerebral hyperperfusion reflects the development of hyperperfusion syndrome. Further, the presence of postoperative CCH in patients with cerebral hyperperfusion following CEA suggests development of postoperative cognitive impairment, even when asymptomatic.

CONCENTRATION OF MALONDIALDEHYDE-MODIFIED LOW-DENSITY LIPOPROTEIN IN THE JUGULAR BULB DURING CAROTID ENDARTERECTOMY CORRELATES WITH DEVELOPMENT OF POSTOPERATIVE COGNITIVE IMPAIRMENT

OBJECTIVE

Approximately 20 to 30% of patients undergoing carotid endarterectomy (CEA) subsequently develop cognitive impairment. The purpose of the present study is to determine whether or not malondialdehyde (MDA)-modified low-density lipoprotein (LDL), a biochemical marker of oxidative damage, concentrations in the jugular bulb during CEA correlates with development of postoperative cognitive impairment.

METHODS

Fifty-five patients undergoing CEA were assessed with a battery of neuropsychological tests before and 1 month after surgery. Serum samples for measurement of MDA-LDL concentration were obtained from a venous catheter inserted into the ipsilateral jugular bulb at the following time points: immediately before clamping of the internal carotid artery (ICA), 10 minutes after clamping of the ICA, and 5 and 20 minutes after declamping of the ICA.

RESULTS

The MDA-LDL concentrations at 5 and 20 minutes after ICA declamping were both significantly higher than concentrations before ICA clamping (P < 0.0001). At the postoperative neuropsychological assessment, six (11%) out of 55 patients showed postoperative cognitive impairment. Logistic regression analysis demonstrated that higher values of MDA-LDL increase (calculated as a percentage of the preclamp values) at either 5 or 20 minutes after ICA declamping were significantly associated with the development of postoperative cognitive impairment (95% confidence interval, 0.787-0.981; P = 0.0209) among the variables tested.

CONCLUSION

MDA-LDL concentration in the jugular bulb during CEA correlates with development of postoperative cognitive impairment.

Killer proteases and little strokes--how the things that do not kill you make you stronger

The phenomenon of ischemic preconditioning was initially observed over 20 years ago. The basic tenant is that if stimuli are applied at a subtoxic level, cells upregulate endogenous protective mechanisms to block injury induced by subsequent stress. Since this discovery, many conserved signaling mechanisms that contribute to activation of this potent protective program have been identified in the brain. A clinical correlate of this basic research finding can be found in patients with a history of transient ischemic attack (TIA), who have a decreased morbidity after stroke. In spite of multidisciplinary efforts to design safer, more effective stroke therapies, we have thus far failed to translate our understanding of endogenous protective pathways to treatments for neurodegeneration. This review is designed to provide clinicians and basic scientists with an overview of stress biology after TIA and preconditioning, discuss new therapeutic strategies to target the protein dysfunction that follows ischemic injury, and propose enhanced biochemical profiling to identify individuals at risk of stroke after TIA. We pay particular attention to the unanticipated consequences of overly aggressive intervention after TIA in which we have found that traditional cytotoxic agents such as free radicals and apoptosis associated proteases is essential for neuroprotection and communication in the stressed brain. These data emphasize the importance of understanding the complex interplay between chaperones, apoptotic proteases including caspases, and the proteolytic degradation machinery in adaptation to neurological injury.

Neuropsychological Outcome 6 Months after Unilateral Carotid Stenting

Percutaneous transluminal angioplasty with stenting (PTAS) has become a treatment option for severe carotid stenosis. The goal of our study was to determine prospectively neurocognitive outcome 6 months after unilateral stent-protected carotid angioplasty. Twenty consecutive patients who underwent stent-protected angioplasty for symptomatic (n=9) or asymptomatic (n=11) high-grade carotid stenosis were investigated and compared to an age and disease matched control group. Patients were administered preprocedurally and 6 months postprocedurally a battery of neuropsychological tests. We used reliable change indices methodology in order to control for practice and statistical effects unrelated to intervention. We found no cognitive change in approximately 90% of patients and cognitive improvement in approximately 10% of patients for concentration and attention variables. We further found no cognitive change in 61% of patients, cognitive improvement in 11% of patients and cognitive deterioration in 28% of patients for psychomotor speed. No cognitive change in 94% of patients and cognitive deterioration in 6% of patients was found for sustained attention; no cognitive change in 80% of patients, cognitive improvement in 15% of patients and cognitive deterioration in 5% of patients was found for verbal fluency; no cognitive change in 100% of patients was found for interference (Stroop test): no cognitive change in 95% of patients, cognitive improvement in 5% of patients was found for interference (c.I. test), respectively. Our study showed that 6 months after PTAS cognitive functioning did not change in most patients significantly. For some patients, however, significant improvement or deterioration in single neurocognitive domains can be expected. The reasons for these changes are unclear but may depend on variable type; magnitude of microemboli production; right vs. left cerebral vasculature, respectively.

Clinical application of transcranial Doppler monitoring for embolic signals

A major advantage of transcranial ultrasound is its suitability for continuous monitoring. Microembolic signals (MES) are brief, high-intensity transients that occur when particulate microemboli or gaseous microbubbles pass through the ultrasound beam. These MES have been detected in several clinical scenarios, but rarely in age-matched controls. The detection of MES provides important pathophysiological information in a variety of disorders, but their clinical importance and possible therapeutic implications are still under debate. The present article summarizes the significance of MES in different clinical settings and outlines some of the problems to be resolved so that transcranial ultrasound can be applied in clinical practice.

Is there improvement of "vascular depression" after carotid artery stent placement?

PURPOSE

To prospectively evaluate if high-grade (> or = 80% luminal narrowing) internal carotid artery stenosis is associated with depressive symptoms and if carotid artery stent placement (CAS) potentially improves depressive symptoms.

MATERIALS AND METHODS

The study was approved by the local ethics committee, and informed consent was obtained from all subjects. One hundred forty-three patients (91 men, 52 women; interquartile range, 63-76 years) undergoing CAS because of asymptomatic high-grade (> or = 80% luminal narrowing) carotid artery stenosis and 102 control subjects (64 men, 38 women; interquartile range, 63-73 years) with advanced peripheral artery disease and without carotid artery stenosis undergoing lower-limb percutaneous transluminal angioplasty were included. Substantial depressive symptoms (defined as a Beck Depression Inventory score of 10 or higher) were recorded at baseline and at 4 weeks (follow-up) after the percutaneous procedures. The chi2 test, Mann-Whitney U test, McNemar test, Wilcoxon rank sum test, and two-group t test were used to check for statistical significance.

RESULTS

A significantly higher prevalence of depressive symptoms was found in patients with carotid artery stenosis than in control subjects with peripheral artery disease at baseline (33.6% vs 16.7%, P = .003). At follow-up, a significant reduction of depressive symptoms was found in patients who underwent CAS (33.6% vs 9.8%, P < .001). The frequency of depressive symptoms remained unaffected in control subjects (16.7% vs 13.0%, P = .1).

CONCLUSION

High-grade carotid artery stenosis is associated with depressive symptoms in patients with atherosclerosis. CAS seems to exert beneficial effects on the course of depressive symptoms in these patients.

Cognitive impairment associated with intraoperative and postoperative hypoperfusion without neurologic deficits in a patient undergoing carotid endarterectomy

BACKGROUND

Neuropsychological testing detects cognitive impairment in 20% to 30% of patients after carotid endarterectomy (CEA).

CASE DESCRIPTION

A 51-year-old man with asymptomatic right cervical internal carotid artery (ICA) stenosis underwent a CEA. Intraoperative transcranial regional cerebral oxygen saturation monitoring revealed ischemia in the right cerebral hemisphere during ICA clamping and transient hyperemia subsequent to ICA declamping. The patient recovered without the appearance of new neurologic deficits. Brain single-photon emission computed tomography performed immediately after CEA showed a decrease in cerebral blood flow in the right cerebral hemisphere. Diffusion-weighted magnetic resonance imaging showed no new abnormal findings. Positron emission tomography performed 2 months after surgery revealed decreased cerebral metabolic rate of oxygen in the right cerebral hemisphere, and neuropsychological testing demonstrated a decline in performance IQ relative to preoperative levels.

CONCLUSIONS

Intraoperative ischemia and postischemic delayed hypoperfusion in CEA can impair cognition even in the absence of development of postoperative neurologic deficit.

Transcranial Doppler Detection of Microembolic Signals During Pulmonary Vein Antrum Isolation: Implications for Titration of Radiofrequency Energy

BACKGROUND

Cerebrovascular events are an important complication during pulmonary vein antrum isolation (PVAI). Microembolic signals (MES) have been associated with stroke and neurological impairment. However, the incidence of MES during PVAI, and their relationship to microbubble formation and radiofrequency (RF) parameters are unknown.

OBJECTIVES

We sought to assess the relationship between MES, microbubble detection, and neurological outcome and the impact of RF titration strategy on these parameters.

METHODS

We studied 202 patients in two groups undergoing PVAI using an intracardiac echocardiography (ICE)-guided technique. MES were detected by transcranial Doppler (TCD) using insonation of the middle cerebral arteries. The number of microbubbles on ICE were qualitatively labeled as FEW, MODERATE, and SHOWER. In group I (n = 107), RF output was titrated to avoid microbubble formation and in group II (n = 95), standard power-limited RF output was used.

RESULTS

TCD detected MES in all 202 patients during PVAI with an average of 1,793 +/- 547 per patient; 90% were detected during left atrial ablation. Over 85% of MES occurred after microbubbles. Group I patients had significantly lower numbers of MES (1,015 +/- 438 per patient) compared to group II patients (2,250 +/- 864 per patient) (P < 0.05). Group II also had a 3.1% incidence of acute neurological complications versus 0.9% in group I (P = 0.10). Patients with clinical events had significantly higher numbers of MES. There were no significant correlations between RF power, temperature, or impedence and MES number.

CONCLUSIONS

MES directly correlate to the amount of microbubble formation on ICE, and may result in cerebroembolic complications. Titration of RF according to microbubble formation by ICE during PVAI may be important for minimizing the occurrence of MES and possibly acute neurological complications.

Rapid measurement of S-100B serum protein levels by Elecsys S100 immunoassay in patients undergoing carotid artery stenting or endarterectomy

OBJECTIVES

This study was designed to apply the rapid Elecsys S100 immunoassay for real-time measurement of S100 protein serum levels indicating acute brain damage in patients undergoing carotid artery stenting (CAS) or endarterectomy (CEA).

DESIGN AND METHODS

Data of 14 CAS patients were compared to those of 43 CEA and 14 control patients undergoing coronary angiography (CA). S100 serum levels were measured by the full-automatic Elecsys S100 immunoassay and compared to those obtained by the well-established LIA-mat S100 system.

RESULTS

In contrast to CAS and CA patients, median S100 serum levels of CEA patients significantly increased to 0.24 ng/mL before declamping, but subsequently returned to baseline. Three CEA patients with neurological deficits showed sustained elevated S100 levels 6 h after extubation. Absolute S100 values were not significantly different between the two methods. Bland-Altman plot analyses displayed a good agreement, mostly indicating slightly smaller values applying the Elecsys S100 system.

CONCLUSIONS

The Elecsys S100 system appears to be suitable for rapid real-time detection of neurological deficits in patients undergoing CAS and CEA. Persistent elevations of Elecsys S100 levels during CEA were associated with prolonged neurological disorders, whereas transient increases seem to represent impaired blood-brain barrier integrity without neurological deficits.

APOE-epsilon4 predisposes to cognitive dysfunction following uncomplicated carotid endarterectomy

BACKGROUND

Between 9% and 23% of patients undergoing otherwise uncomplicated carotid endarterectomy (CEA) develop subtle cognitive decline 1 month postoperatively. The APOE-epsilon4 allele has been associated with worse outcome following stroke.

OBJECTIVE

To investigate the ability of APOE-epsilon4 to predict post-CEA neurocognitive dysfunction.

METHODS

Seventy-five patients with CEA undergoing elective CEA were prospectively recruited in this nested cohort study and demographic variables were recorded. Patients were evaluated before and 1 month after surgery with a standard battery of five neuropsychological tests. APOE genotyping was performed by restriction fragment length polymorphism analysis in all patients. Neuropsychological deficits were identified by comparing changes (before to 1 month post-operation) in individual performance on the test battery. Logistic regression was performed for APOE-epsilon4 and previously identified risk factors.

RESULTS

Twelve of 75 (16%) CEA patients possessed the APOE-epsilon4 allele. Eight of 75 (11%) patients experienced neurocognitive dysfunction on postoperative day 30. One month post-CEA, APOE-epsilon4-positive patients were more likely to be cognitively injured (42%) than APOE-epsilon4-negative patients (5%) (p = 0.002). In multivariate analysis, the presence of the APOE-epsilon4 allele increased the risk of neurocognitive dysfunction at 1 month 62-fold (62.28, 3.15 to 1229, p = 0.007). Diabetes (51.42, 1.94 to 1363, p = 0.02), and obesity (24.43, 1.41 to 422.9, p = 0.03) also predisposed to injury.

CONCLUSION

The APOE-epsilon4 allele is a robust independent predictor of neurocognitive decline 1 month following CEA.

Cognitive functions in patients with cerebrovascular disease: potential impact of revascularization

The purpose of this review is to assess the impact of luminal restoring of carotid artery stenosis on cognitive functions. Therefore, papers dealing with the neuropsychological influence of carotid artery stenosis and studies comparing the neuropsychological course after respective recanalization have been included.

Risk factors for periprocedural complications in carotid artery stenting without filter protection

INTRODUCTION

In high-grade stenosis, carotid artery stenting (CAS) may be chosen as an alternative to carotid surgery. Ischemic periprocedural complications may be documented best with diffusion-weighted MRI (DWMRI). In this prospective study serial DW-MRI and color-coded duplex sonography (CCDS) were used to identify carotid stenosis, which is associated with an increased risk of ischemic events due to CAS.

METHODS

High resolution DW-MRI were performed in 74 out of 77 patients before and after CAS. All MRI scans were analyzed in a blinded manner. With CCDS each carotid stenosis was evaluated according to the grade, length, echo properties and plaque surface.

RESULTS

In 42 out of 74 patients (56.8 %) a total of 188 new procedure- related DWI-lesions could be detected, while in 32 patients MRI-controls remained normal. Of the lesions 79.25 % had a size < 1 cm. In one major and two minor strokes due to CAS (total complication rate 3.9 %) corresponding territorial infarcts could be demonstrated. A highly significant correlation was found between the length of the stenosis and the incidence of new DWI-lesions (p = 0.0141). In contrast, neither the grade of ICA stenosis nor the sonographic plaque morphology or plaque surface correlated with the number of DWI-lesion in postinterventional scans.

CONCLUSIONS

The length-and not the degree-of an ICA stenosis seems to be the most decisive sonographic factor for estimating the periprocedural risk of embolism. DWI-lesions are much more frequent than clinical complications and may represent an important surrogate marker for improving the techniques of carotid artery stenting, especially comparing the benefit of different mechanical protection devices.

Effects of the free radical scavenger, edaravone, on the development of postoperative cognitive impairment in patients undergoing carotid endarterectomy

BACKGROUND

Some patients undergoing carotid endarterectomy (CEA) experience postoperative cognitive impairment. The purpose of the present case cohort study with historical control was to determine whether pretreatment with a novel free radical scavenger, edaravone, could prevent development of cognitive impairment after CEA.

METHODS

Fifty-five patients with ipsilateral internal carotid artery (ICA) stenosis (> or =70%) underwent CEA with administration of edaravone before ICA clamping. Neuropsychological testing was performed preoperatively and at the first postoperative month. Cerebral blood flow was also measured using single-photon emission computed tomography before and immediately after CEA and on the third postoperative day.

RESULTS

Postoperative cognitive impairment was observed in only 1 (2%) patient, who exhibited postoperative cerebral hyperperfusion (cerebral blood flow increase > or =100% compared with preoperative values). Incidence of postoperative cognitive impairment in the control group (92 CEA patients without administration of edaravone) was significantly higher (12%) (P = .0298, control vs treatment group). Logistic regression analysis demonstrated that postoperative cerebral hyperperfusion and absence of pretreatment with edaravone were significant independent predictors of postoperative cognitive impairment.

CONCLUSION

Pretreatment with edaravone can prevent development of cognitive impairment after CEA.

The capture of visible debris by distal cerebral protection filters during carotid artery stenting: Is it predictable?

OBJECTIVES

Neurologic complications during carotid artery stenting (CAS) are most clearly associated with embolization of visible debris. Distal filter devices may provide cerebral protection by capturing clinically significant debris. However, they increase procedural time and expense and have their own set of complications. The current study was undertaken to identify the clinical factors predictive for the presence or absence of visible debris captured by distal filter devices during CAS.

METHODS

Patients undergoing CAS with use of a distal filter device (n = 279) were prospectively entered into an investigational carotid registry. Recorded variables were classified as patient-, lesion-, or procedure-related. The filter was assessed for visible debris in each case. The odds ratio (OR) and 95% confidence interval (CI) were determined for each variable to predict visible debris. The ability of each variable to predict the absence of visible debris was assessed by calculating the individual negative predictive value (NPV).

RESULTS

Visible debris was present in 169 filters (60.3%). There was an increased risk of visible debris found with several variables (OR, 95% CI): hypertension (2.9, 1.7 to 5.2), hypercholesterolemia (2.3, 1.4 to 3.9), stent diameter >9 mm (16.6, 9.0 to 30.0), and any neurologic event (4.2, 1.5 to 9.9). The NPV failed to exceed 0.80 (80%) for any variable. The NPV of the variables with a significantly elevated OR was as follows: hypertension (0.60), hypercholesterolemia (0.52), stent diameter >9 mm (0.75), and any neurologic event (0.38).

CONCLUSIONS

Several clinical variables are associated with the presence of visible debris captured by distal filter devices. The current study failed to identify any variables capable of consistently predicting the absence of visible debris. These findings support the routine rather than the selective use of cerebral protection during CAS.

Neural Damage Caused by Cerebral Hyperperfusion after Arterial Bypass Surgery in a Patient with Moyamoya Disease: Case Report

OBJECTIVE AND IMPORTANCE:

The prognosis of cerebral hyperperfusion syndrome after vascular reconstructive surgery, including extracranial-intracranial arterial bypass, is not poor unless intracerebral hemorrhage develops secondary to hyperperfusion.

CLINICAL PRESENTATION:

A 48-year-old man with symptomatic moyamoya disease with misery perfusion in the right cerebral hemisphere underwent double right superficial temporal artery-to-middle cerebral artery bypasses. The postoperative course was uneventful until the patient developed headache and agitated delirium on the 4th postoperative day.

INTERVENTION:

Perfusion computed tomographic imaging demonstrated hyperperfusion in the right temporal lobe. The symptoms resolved by institution of intensive blood pressure control. Positron emission tomography performed 2 months after surgery demonstrated a postoperative reduction of the cerebral metabolic rate of oxygen in the right temporal lobe, where brain atrophy was observed on magnetic resonance images 3 months postoperatively. Neuropsychological testing performed 3 months postoperatively showed worsening digit span, which adversely affected the patient's quality of life.

CONCLUSION:

The current case suggests that cerebral hyperperfusion after vascular reconstructive surgery can cause irreversible neural damage, which results in cognitive impairment.

Angioplasty and stenting of the cervical carotid bifurcation under filter protection: a prospective study in a series of 53 patients

The aim of this study is to assess safety, reliability, ease of use and usefulness of filter protection devices during angioplasty and stenting of stenotic lesions of the cervical carotid bifurcation. Over a period of 42 months, 53 patients harboring a cervical carotid bifurcation stenotic lesion were treated, by angioplasty and/or stenting using filter protection devices of different kinds. The stenosis was atherosclerotic in 48 cases, post-surgical in four and post-radiation in one case. In all cases, the treatment was successful, with good restoration of the luminal diameter. There were three major strokes (5.6%) and one minor stroke (1.9%). Two of these (one major, one minor) occurred a few hours after the stenting procedure and both seemed by all evidence due to a hemorrhagic hyperperfusion syndrome. One hemiparesis and dysphasia occurred two days after the procedure, secondary to subacute thrombosis with occlusion of the stent. One patient complained of three episodes of decrease in visual acuity of the eye ipsilateral to the stenting in the two weeks following treatment. In conclusion, in our experience, use of the devices adds only few minutes to the procedure time; direct lesions of the arterial wall, such as dissections or intraluminal thrombi, related to the use of filters were never observed, and spasm of the distal I.C.A. also proved rapidly regressive. The content of all filters, if any, was histologically examined, but plaque material was found only in one case, probably owing to our primary stenting technique without use of pre-dilation. The major technical drawback is in-filter coagulation, which occurred in 16 cases, occluding the membrane of the filter and thus slowing or blocking intracranial flow. Such an event can be counteracted by a more aggressive anti-coagulation protocol, which could, however, be responsible for the two complications with hemorrhagic brain infarction. Furthermore, we observed two other major neurological events, which bring the incidence of neurological complications in this series as high as 7.5%. Therefore, it is our opinion that safety of filters is not yet proven, and consequently great care must be taken in their use.

Perioperative Microembolism is not Associated with Cognitive Outcome Three Months after Carotid Endarterectomy

OBJECTIVE

To investigate the association between perioperative microembolism and cognitive outcome 3 months after carotid endarterectomy (CEA).

DESIGN

Prospective study.

MATERIALS AND METHODS

Patients were tested 1 day before and 3 months after surgery with neuropsychological tests measuring a wide range of cognitive functions. Number of microemboli was monitored with transcranial Doppler ultrasonography in 58 patients during the operation and in a random subgroup of 27 patients directly following the procedure.

RESULTS

Forty patients (69%) had intraoperative embolism, varying from 1 to 33 isolated microemboli and/or 1 to 11 embolic showers. Postoperative emboli were present in 22 of the 27 patients (81%), ranging from 1 to 142 isolated microemboli. More than 10 microemboli (including showers) were detected in 13 patients (22%) intraoperatively and in 6 patients (22%) postoperatively. Twenty-two patients (38%) showed deterioration in three or more cognitive function variables at 3 months. There were no significant associations between any cognitive change or deterioration score and presence or number of intraoperative and/or postoperative emboli.

CONCLUSIONS

The degree of microembolism during and immediately following CEA is generally small and seems to be of no significance with respect to postoperative cognitive functioning. Future research should include a larger group of patients to allow reliable subgroup analysis.

Postoperative cerebral hyperperfusion associated with impaired cognitive function in patients undergoing carotid endarterectomy

Object. Cognitive impairment occurs in 20 to 30% of patients following carotid endarterectomy (CEA). The purpose of the present study was to determine whether postoperative cerebral hyperperfusion is associated with impairment of cognitive function in patients undergoing that procedure.

Methods. Cerebral blood flow (CBF) was measured using single-photon emission computerized tomography scanning before and immediately after CEA and on the 3rd postoperative day in 92 patients with ipsilateral internal carotid artery stenosis of 70% or greater. Hyperperfusion post-CEA was defined as a 100% increase or greater in CBF compared with preoperative values. Neuropsychological testing was also performed preoperatively and at the 1-, 3-, and 6-month follow-up examinations.

At the 1-month postoperative neuropsychological assessment, 11 patients (12%) displayed evidence of cognitive impairment. In addition, the incidence of postoperative cognitive impairment in patients with post-CEA hyperperfusion (seven [58%] of 12 patients) was significantly higher than that in patients without post-CEA hyperperfusion (four [5%] of 80 patients; p < 0.0001). A logistic regression analysis demonstrated that post-CEA hyperperfusion was the only significant independent predictor of postoperative cognitive impairment. Of the seven patients in whom post-CEA hyperperfusion and cognitive impairment were identified 1 month postoperatively, four (including three patients with hyperperfusion syndrome) remained cognitively impaired at the 3- and 6-month follow-up examinations.

Conclusions. Postoperative cerebral hyperperfusion is associated with impairment of cognitive function in patients undergoing CEA. Furthermore, the development of hyperperfusion syndrome is associated with the persistence of postoperative cognitive impairment.

Cerebral ischemia after carotid intervention

PURPOSE

To determine the incidence of symptomatic and asymptomatic cerebral ischemic lesions found on diffusion-weighted magnetic resonance imaging (DW-MRI) after carotid interventions.

METHODS

A prospective study was conducted to assess new cerebral ischemic lesions using DW-MRI in symptomatic patients with carotid artery disease undergoing protected carotid artery stenting (CAS) or carotid endarterectomy (CEA). DW-MRI was performed before and after the intervention in 44 patients (21 CAS and 23 CEA). Two experienced radiologists not involved in the carotid procedures or neurological assessment compared the postprocedural DW-MR images with those acquired before the intervention.

RESULTS

Three (6.8%) of the 44 patients suffered strokes: 1 major and 1 minor stroke after CEA and 1 minor stroke after CAS. DW-MRI showed 15 new hyperintense lesions in 2 (9%) of 23 CEA patients; 31 new hyperintense lesions were found in 9 (43%) of the 21 CAS patients. The majority of new lesions were located in the ipsilateral vascular territory; 2 CAS patients also showed 6 new hyperintense lesions in the cerebellum. The mean lesion load per patient was 2.52 cm(3) (range 0.31-4.74) in the CEA group and 1.74 cm(3) (0.03-9.72) in the CAS group (p=0.35). The volume of the individual lesions in CEA patients was 0.39 cm(3) (range 0.01-2.16) compared to 0.52 cm(3) (range 0.01-5.47) in the CAS group (p=0.23). Patients who were asymptomatic after the intervention had fewer lesions (p=0.03) and a smaller lesion load than symptomatic patients.

CONCLUSIONS

Ischemic lesions were more frequently seen on DW-MRI after carotid stenting than after endarterectomy. The majority of the detected lesions did not cause neurological deficits.

Differences in number, size and location of intracranial microembolic lesions after surgical versus endovascular treatment without protection device of carotid artery stenosis

BACKGROUND AND PURPOSE

The benefit of carotid endarterectomy in symptomatic high-grade stenosis has long been proven. The role of angioplasty as an alternative is still a matter of debate. We compared the occurrence of intraprocedural microembolic signals and ischemic lesions between carotid endarterectomy (CEA) and carotid angioplasty with stent placement (CAS) without a protection device.

METHODS

88 patients who underwent a CEA and 41 patients who underwent CAS were prospectively investigated. One day before and after the intervention diffusion weighted MRI-studies were obtained. In 21 CEA and 18 CAS patients transcranial Doppler (TCD) monitoring was performed during the procedure to detect microembolic signals (MES).

RESULTS

DWI-lesions could be detected after intervention in 17% of the CEA patients compared with 54% of the CAS patients (p<0.005). The median lesion volume was 0.08 cm(3) in the CEA group and 0.02 cm(3) in the CAS group (p<0.001). Ischemic complications consisted of 2 strokes (2.3%) with symptoms lasting more than seven days in the CEA group and 1 stroke (2.4 %) in the CAS group. The median number of MES in the CEA group was 17 versus 61 in the CAS group (p<0.001). No significant correlation was found between the total number of MES and ischemic lesions in either group.

CONCLUSION

A larger number of emboligenic particles with smaller volume is detached during CAS. Additionally DWI lesions were observed in different territories after CAS but not after CEA. Conventional TCD emboli detection is not useful to compare interventional therapies of the carotid arteries.

Current concepts of mechanical cerebral protection during precutaneous carotid intervention

Major advances in the endovascular treatment of carotid artery stenosis are underway, with an emphasis on improving the safety profile of the technique. This review highlights key areas in the concepts and design of available mechanical neuroprotection devices utilized during carotid stenting to minimize procedural cerebral embolization. The advantages and disadvantages of each system are explored and the available clinical experience is given. The size threshold of particulate material likely to be clinically relevant is examined and compared with pathological analysis of particles trapped by protection systems reported in the world literature. It is shown that the adverse neurological event rate in those protected is lower than that in historical studies of unprotected carotid stenting. Furthermore, the size range and numbers of particles trapped by protections systems are sufficient to cause potential neurological injury if allowed passage to the brain. Further improvements in outcomes may require further refinement of protection technology.