Periprocedural hemodynamic depression is associated with a higher number of new ischemic brain lesions after stenting in the International Carotid Stenting Study-MRI Substudy

Changes in Cognitive Functions after Carotid Endarterectomy and Carotid Stenting: A Decade-Apart Comparison

BACKGROUND

This study investigates changes in cognitive function in patients with severe carotid stenosis who underwent carotid endarterectomy (CEA) and carotid stenting (CAS) over two decades.

METHODS

We compared cognitive function within 30 days after the procedure in 267 patients (first 100 each for CEA and CAS in two periods: 2008-2012 and 2018-2022) in a single institution. Assessments used Adenbrooke's Cognitive Examination-Revised (ACE-R), the Mini-Mental State Examination (MMSE), Speech Fluency Test (SFT), and Clock Drawing Test (CDT), conducted before and 30 ± 2 days after surgery.

RESULTS

Patients (mean age 67.2 years, 70%+ carotid stenosis) exhibited different cognitive changes over periods. In 2008-2012, significant declines in MMSE (CEA, p = 0.049) and CDT (CAS, p = 0.015) were observed among asymptomatic patients. On the contrary, in 2018-2022, improvements were observed in ACE-R and MMSE for symptomatic and asymptomatic patients undergoing CEA and CAS.

CONCLUSION

Over a decade, advances in interventional techniques and patient management have reduced risks of cognitive decline in patients with asymptomatic carotid stenosis and also have improved cognitive functions in both symptomatic and asymptomatic individuals.

Hemodynamic depression after carotid surgery: Incidence, risk factors and outcomes

INTRODUCTION

Hemodynamic Depression (HD) characterized by hypotension and bradycardia is a complication of carotid surgery due to direct autonomic stimulation in the carotid sinus. The authors believe the incidence of HD is high and possibly related to major cardiac complications.

METHODS

Analysis of patient records during admissions for carotid surgery between January 2014 and December 2018 in two hospitals. HD was defined as bradycardia or hypotension in the first 24 postoperative hours. Bradycardia was defined as heart rate < 50bpm; hypotension as systolic blood pressure < 90 mmHg, continuous use of vasopressors, or a drop in SBP > 20% compared to preoperative values. Myocardial infarction, stroke, and cardiovascular death were defined as adverse events.

RESULTS

Overall, 237 carotid surgeries (178 endarterectomies, 59 angioplasties) were studied, and the global incidence of HD was 54.4% (hypotension in 50.2%, bradycardia in 11.0%, and hypotension and bradycardia in 6.8%). The independent predictors of HD were asymptomatic carotid stenosis (OR = 1.824; 95% CI 1.014-3.280; p = 0.045), endovascular surgery (OR = 3.319; 95% CI 1.675-6.576; p = 0.001) and intraoperative hypotension or bradycardia (OR = 2.144; 95% CI 1.222-3.762; p = 0.008). Hypotension requiring continuous vasopressor infusion was the only factor independently associated with adverse cardiovascular events (OR = 5.504; 95% CI 1.729-17.529; p = 0.004).

DISCUSSION/CONCLUSION

Incidence of Hemodynamic Depression after carotid surgery is high and independently associated with surgical technique, symptomatic repercussion of the carotid stenosis, and intraoperative hypotension or bradycardia. Hypotension requiring the continuous infusion of vasopressors was independently associated with the occurrence of MACE.

The correlation between the cardiovascular instability and the size of the developed ischaemic lesions in patients who underwent carotid stenting

AIMS

In this study we investigated the relationship between cardiovascular instability and the size of the developed ischaemic lesions during carotid stent implantation by diffusion-weighted (DWI) magnetic resonance (MR) examination.

MATERIAL AND METHODS

We retrospectively analyzed anaesthesia reports and follow-up MR examinations after stent implantation of 192 patients in a 3-year period. Nineteen aspects of cardiovascular status were analyzed. We registered the duration of the intervention, low and high blood pressure (BP) values during anaesthesia and heart rates. The fluctuations of BP and heart rate and the time of their compensations after the stent expansion were also recorded. Values were compared with the number and the size of ischaemic lesions on DWI scans. We used Spearman and Kendall rank correlations and Welch's tests for statistical analysis. Values of p ≤ 0.05 were considered as statistically significant.

RESULTS

Decreased heart rate significantly correlated with the number (p = 0.0123) and size (p = 0.00323) of ischaemic lesions during stent expansion. Other cardiovascular parameters did not show any significant correlations.

CONCLUSIONS

Our results indicate that only heart rate attenuation affects the size of ischaemic lesions; thus the prevention of bradycardia is highly important.

Predisposing Factors and Management of Hemodynamic Depression Following Carotid Artery Stenting

Carotid artery stenting (CAS) involves dilatation of carotid bulb which can trigger a series of neuronal responses resulting in hemodynamic depression that might influence the outcome of the procedure. This is a frequent but underdiagnosed complication of CAS. Although it is mild, transient and self-limiting in majority of cases, it can result in significant morbidity and mortality if persistent. Neurologists should be aware of the predisposing factors and management of this common complication. In patients who present with stroke following carotid stenting, neurologists should be aware of hypoperfusion secondary to hemodynamic depression as a cause of stroke apart from the stent thrombosis and occlusion.

Procedural Stroke after Carotid Revascularization - Critical Analysis of the Literature and Standards of Reporting

OBJECTIVE

Mechanisms of procedural stroke after carotid endarterectomy (CEA) or stenting (CAS) are surprisingly underresearched. However, understanding the underlying mechanism could: (1) assist in balancing the choice for revascularization versus conservative therapy; (2) assist in choosing either open or endo techniques; and (3) assist in taking appropriate periprocedural measures to further reduce procedural stroke rate. The purpose of this study was to overview mechanisms of procedural stroke after carotid revascularization and establish reporting standards to facilitate more granular investigation and individual patient data meta-analysis in the future.

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) statement.

RESULTS

The limited evidence in literature was heterogeneous and of low quality and hence no formal data meta-analysis could be performed. Procedural stroke was classified as haemorrhagic or ischemic; the latter was subclassified as haemodynamic, embolic (carotid- or cardio-embolic) or carotid occlusion-derived, using a combination of clinical inference and imaging data. Most events occurred in the first 24h after the procedure and were related to hypoperfusion (pooled incidence 10.2% (95% c.i. 3.0-17.5) versus 13.9% (95% c.i. 0.0-60.9) post-CEA vs CAS events, respectively) or atheroembolism (28.9% (95% c.i. 10.9-47.0) versus 34.3 (95% c.i. 0.0-91.5)) After the first 24 hours, haemorrhagic stroke (11.6 (95% c.i. 5.7-17.4) versus 9.0 (95% c.i. 1.3-16.7)) or thrombotic occlusion (18.4 (95% c.i. 0.9-35.8) versus 14.8 (95% c.i. 0.0-30.5)) became more likely.

CONCLUSIONS

Although procedural stroke incidence and aetiology may have changed over the last decades due to technical improvements and improvement in perioperative monitoring and quality control, the lack of literature data limits further statements. To simplify and enhance future reporting, procedural stroke analysis and classification should be documented pre-emptively in research settings. We propose a standardized form enclosing reporting standards for procedural stroke with a systematic approach to inference of the most likely aetiology, for prospective use in registries and RCTs on carotid revascularization.

Analysis of postprocedural microembolic infarctions and global oxygen extraction fraction during balloon-protected carotid artery stenting: Preliminary study

Background:

Atherosclerotic carotid stenosis with impaired cerebral perfusion is a risk factor for cerebral ischemia. In major carotid stenoocclusive diseases, increased oxygen extraction fraction (OEF) is associated with ischemic stroke. Balloon-protected carotid artery stenting (CAS) is valuable for high-grade carotid stenosis. However, while balloon-protected CAS can effectively reduce the occurrence of ischemic complications by blocking carotid flow, cerebral hypoperfusion may result in simultaneous cerebral ischemia. We sought to evaluate whether increased OEF during balloon-protected CAS can predict postprocedural microembolic infarction (MI).

Methods:

Eighty-four patients who underwent balloon-protected CAS were enrolled. Initial, intraprocedural, and postprocedural OEFs were calculated from the cerebral arteriovenous oxygen differences obtained from blood sampled just before the temporary occlusion and reperfusion of the internal carotid artery during and after the procedure. MIs were evaluated by diffusion-weighted imaging (DWI). Patients were classified into two groups based on the presence or absence of new MIs, and the relationship between the OEF and postprocedural MIs was analyzed.

Results:

New DWI-positive lesions were found in 37 cases (44.0%). Age, signal intensity ratio (SIR) of carotid plaque on T1-weighted black blood magnetic resonance imaging, and intraprocedural OEF were significantly higher in the DWI-positive group. The high SIR and intraprocedural OEF were significantly associated with the development of postprocedural MIs in multivariate analysis. MIs were correlated with the increase in OEF.

Conclusion:

Increased intraprocedural OEF, obtained by blood sampling during balloon-protected CAS, could predict the incidence of postprocedural MIs. Patients with carotid stenosis could be hemodynamically compromised by carotid flow blockage during balloon-protected CAS.

Factors associated with hemodynamic instability following carotid artery stenting

OBJECTIVE

Carotid artery stenting (CAS) is a major treatment option for carotid artery stenosis, and a recognized alternative to carotid endarterectomy (CEA). However, CAS-related hemodynamic instability occurs frequently and is a known major risk factor of associated complications. This study was undertaken to identify the risk factors of hemodynamic instability associated with CAS.

METHODS

We analyzed the medical records of 128 patients with carotid artery stenosis treated by CAS at our institution from 2014 to 2019 to identify the risk factors of hemodynamic instability after CAS. In addition, the incidences of hemodynamic instability, including bradycardia and hypotension, during and after the procedure were investigated.

RESULTS

Overall, periprocedural bradycardia requiring atropine occurred in 18 (14.1 %) of the 128 study subjects, and postprocedural persistent hypotension requiring vasopressors occurred in 15 (11.7 %). Risk-adjusted analysis showed carotid bulb involvement of a stenotic lesion was an independent risk factor of periprocedural bradycardia (OR 4.25, 95 % CI 1.34-13.40) and postprocedural persistent hypotension (OR 7.36, 95 % CI 1.86-29.12). However, though a preoperative regimen of ≥ 2 antihypertensives was found to be an independent protective factor against postprocedural persistent hypotension (OR 0.17, 95 % CI 0.04-0.81), it was not associated with periprocedural bradycardia (OR 0.37 95 % CI 0.08-1.60).

CONCLUSIONS

The risk of hemodynamic instability development is greater when a carotid stenotic lesion involves the carotid bulb, which cautions that careful evaluation is necessary. In addition, the receipt of antihypertensive regimens before CAS had a protective effect on persistent hypotension after CAS, but did not affect bradycardia.

The conundrum of asymptomatic carotid stenosis-determinants of decision and evidence

Management of asymptomatic carotid disease continues to challenge medical practice and present evidence is often conflicting. Stroke is a significant burden in Public Health and 11% to 15% appear as first neurologic event associated with asymptomatic carotid stenosis. Randomized trials provided support for Guidelines and Recommendations to intervene on asymptomatic stenosis, but at a known cost of a high number of unnecessary operations. Conflicting evidence from natural history studies and the widespread use of proper medical management including risk factors control, lowering-lipid drugs and strict control of arterial hypertension have reduced the incidence of strokes associated to asymptomatic carotid disease challenging established practice. Need to identify vulnerable lesions prone to develop thromboembolic brain events and also vulnerable patients at a higher risk of stroke is necessary and essential to further improve effectiveness of our interventions. After review of published literature on natural history of asymptomatic carotid stenosis, diagnostic methods to identify plaque vulnerability and present-day results of both endarterectomy and stenting, a strategy for management of asymptomatic carotid stenosis is suggested aiming to reduce unnecessary interventions and effectively contribute to stroke prevention.

Residual stenosis after carotid artery stenting: Effect on periprocedural and long-term outcomes

Objective

This study investigated the effect of residual stenosis after carotid artery stenting (CAS) on periprocedural and long-term outcomes.

Methods

Patients treated with CAS for symptomatic or asymptomatic carotid arterial stenosis were consecutively enrolled. Residual stenosis was estimated from post-procedure angiography findings. The effects of residual stenosis on 30-day periprocedural outcome and times to restenosis and clinical outcome were analyzed using logistic regression models and Wei-Lin-Weissfeld models, respectively.

Results

A total of 412 patients (age, 64.7 ± 17.0 years; male, 82.0%) were enrolled. The median baseline stenosis was 80% (interquartile range [IQR], 70–90%), which improved to 10% (0–30%) for residual stenosis. Residual stenosis was significantly associated with periprocedural outcome (adjusted odds ratio, 0.983; 95% confidence interval [CI], 0.965–0.999, P = 0.01) after adjustment for baseline stenosis, age, hypertension, symptomaticity, and statin use. Over the 5-year observation period, residual stenosis did not increase the global hazard for restenosis and clinical outcome (adjusted hazard ratio, 1.011; 95% CI, 0.997–1.025. In the event-specific model, residual stenosis increased the hazard for restenosis (adjusted hazard ratio, 1.041; 1.012–1.072) but not for clinical outcome (adjusted hazard ratio, 1.011; 0.997–1.025).

Conclusions

Residual stenosis after carotid artery stenting may be useful to predict periprocedural outcome and restenosis.

Editor's Choice - Overview of Primary and Secondary Analyses From 20 Randomised Controlled Trials Comparing Carotid Artery Stenting With Carotid Endarterectomy

OBJECTIVES

The aim of this review was to carry out primary and secondary analyses of 20 randomised controlled trials (RCTs) comparing carotid endarterectomy (CEA) with carotid artery stenting (CAS).

METHODS

A systematic review and meta-analysis of data from 20 RCTs (126 publications) was carried out.

RESULTS

Compared with CEA, the 30 day death/stroke rate was significantly higher after CAS in seven RCTs involving 3467 asymptomatic patients (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.02-2.64) and in 10 RCTs involving 5797 symptomatic patients (OR 1.71, 95% CI 1.38-2.11). Excluding procedural risks, late ipsilateral stroke was about 4% at 9 years for both CEA and CAS, i.e., CAS was durable. Reducing procedural death/stroke after CAS may be achieved through better case selection, e.g., performing CEA in (i) symptomatic patients aged > 70 years; (ii) interventions within 14 days of symptom onset; and (iii) situations where stroke risk after CAS is predicted to be higher (segmental/remote plaques, plaque length > 13 mm, heavy burden of white matter lesions [WMLs], where two or more stents might be needed). New WMLs were significantly more common after CAS (52% vs. 17%) and were associated with higher rates of late stroke/transient ischaemic attack (23% vs. 9%), but there was no evidence that new WMLs predisposed towards late cognitive impairment. Restenoses were more common after CAS (10%) but did not increase late ipsilateral stroke. Restenoses (70%-99%) after CEA were associated with a small but significant increase in late ipsilateral stroke (OR 3.87, 95% CI 1.96-7.67; p < .001).

CONCLUSIONS

CAS confers higher rates of 30 day death/stroke than CEA. After 30 days, ipsilateral stroke is virtually identical for CEA and CAS. Key issues to be resolved include the following: (i) Will newer stent technologies and improved cerebral protection allow CAS to be performed < 14 days after symptom onset with risks similar to CEA? (ii) What is the optimal volume of CAS procedures to maintain competency? (iii) How to deliver better risk factor control and best medical treatment? (iv) Is there a role for CEA/CAS in preventing/reversing cognitive impairment?

Safety of simultaneous bilateral carotid artery stenting for bilateral carotid artery stenosis

BACKGROUND

Bilateral carotid artery stenting (BCAS) is often performed in two stages (staged BCAS) but it is also an option to be performed in one stage (simultaneous BCAS). To confirm the safety of simultaneous BCAS, we retrospectively analyzed perioperative and postoperative course of simultaneous BCAS compared with staged BCAS.

MATERIALS AND METHODS

Patients with symptomatic stenosis of ≥50% or asymptomatic stenosis of ≥80% of bilateral carotid arteries underwent BCAS. Procedure time, symptomatic ischemic complications, presence/absence of high-intensity spots on postoperative diffusion-weighted image, duration of postoperative hospital stays and 30 days outcome of patients performed with simultaneous BCAS (group A, 8 patients with 16 stenotic lesions (8 procedures)) were compared with those of staged BCAS (group B, 4 patients with 8 stenotic lesions (8 procedures)).

RESULTS

In groups A and B, procedure time was 146.0 ± 53.8 and 103.5 ± 39.4 min; intraoperative hypotension was observed in 62.5% and 50.0%; postoperative hypotension occurred in 37.5% and 50.0%; diffusion-weighted image showed high-intensity spots in 37.5% and 12.5%; and duration of postoperative hospital stays was 5.1 ± 1.8 and 5.3 ± 2.3 days. No patients suffered symptomatic ischemic complications. In simultaneous BCAS, there was a tendency that procedure time was longer and high-intensity spots on postoperative diffusion-weighted image was more frequent, but there was no increase in symptomatic ischemic complications and duration of hospital stays compared to staged BCAS.

CONCLUSIONS

Safety of simultaneous BCAS may not be inferior to staged BCAS. In terms of duration of hospital stays, simultaneous BCAS can be superior to staged BCAS for patients with bilateral carotid artery stenosis.

Technical improvements in carotid revascularization based on the mechanism of procedural stroke

The benefit of carotid revascularization in patients with severe carotid artery stenosis is hampered by the risk of stroke due to the intervention itself. The risk of periprocedural strokes is higher for carotid artery stenting (CAS) as compared to carotid endarterectomy (CEA). Over the past years, the pathophysiological mechanism responsible for periprocedural stroke seems to unfold step by step. Initially, all procedural strokes were thought to be the result of technical errors during surgical repair: cerebral ischemia due to clamping time of the carotid artery, cerebral embolization of atherosclerotic debris due to manipulation of the atheroma or thrombosis of the artery. Following improvements in surgical techniques, technical skills, new intraoperative monitoring technologies such as angioscopy, and the results of the first large clinical randomized controlled trials (RCT) it was believed that most periprocedural strokes were of thromboembolic nature, while a large part of these caused by technical error. Nowadays, analyses of underlying pathophysiological mechanisms of procedural stroke make a clinically relevant distinction between intra-procedural and postprocedural strokes. Intra-procedural stroke is defined as hypoperfusion due to clamping (CEA) or dilatation (CAS) and embolization from the carotid plaque (both CEA and CAS). Postprocedural stroke can be caused by thrombo-embolisation but seems to have a primarily hemodynamic origin. Besides thrombotic occlusion of the carotid artery, cerebral hyperperfusion syndrome (CHS) due to extensively increased cerebral revascularization is the most reported pathophysiological mechanism of postprocedural stroke. Multiple technical improvements have attempted to lower the risk of periprocedural stroke. The introduction of antiplatelet therapy (APT) has significantly reduced the risk of thromboembolic events in patients with carotid stenosis. Over the years, recommendations regarding APT changed. While for a long time APT was discontinued prior to surgery because of a fear of increased bleeding risk, nowadays continuation of APT during carotid intervention (aspirin monotherapy or even dual APT including clopidogrel) is found to be safe and effective. In CAS patients, dual APT up to three months' postprocedural is considered best. Stent design and cerebral protection devices (CPD) for CAS procedure are continuously under development. Trials have suggested a benefit of closed-cell stent design over open-cell stent design in order to reduce procedural stroke, while the benefit of CPD during stenting is still a matter of debate. Although CPD reduce the risk of procedural stroke, a higher number of new ischemic brain lesions detected on diffusion weighted imaging was found in patients treated with CPD. In patients undergoing CEA under general anesthesia, adequate use of cerebral monitoring (EEG and transcranial Doppler [TCD]) has reduced the number of intraoperative stroke by detecting embolization and thereby guiding the surgeon to adjust his technique or to selectively shunt the carotid artery. In addition, TCD is able to adequately identify and exclude patients at risk for CHS. For CAS, the additional value of periprocedural cerebral monitoring to prevent strokes needs urgent attention. In conclusion, this review provides an overview of the pathophysiological mechanism of stroke following carotid revascularization (both CAS and CEA) and of the technical improvements that have contributed to reducing this stroke risk.

Silent brain infarcts on diffusion-weighted imaging after carotid revascularisation: A surrogate outcome measure for procedural stroke? A systematic review and meta-analysis

Aim

To investigate whether lesions on diffusion-weighted imaging (DWI+) after carotid artery stenting (CAS) or endarterectomy (CEA) might provide a surrogate outcome measure for procedural stroke.

Materials and Methods

Systematic MedLine® database search with selection of all studies published up to the end of 2016 in which DWI scans were obtained before and within seven days after CAS or CEA. The correlation between the underlying log odds of stroke and of DWI+ across all treatment groups (i.e. CAS or CEA groups) from included studies was estimated using a bivariate random effects logistic regression model. Relative risks of DWI+ and stroke in studies comparing CAS vs. CEA were estimated using fixed-effect Mantel-Haenszel models.

Results

We included data of 4871 CAS and 2099 CEA procedures (85 studies). Across all treatment groups (CAS and CEA), the log odds for DWI+ was significantly associated with the log odds for clinically manifest stroke (correlation coefficient 0.61 (95% CI 0.27 to 0.87), p = 0.0012). Across all carotid artery stenting groups, the correlation coefficient was 0.19 (p = 0.074). There were too few CEA groups to reliably estimate a correlation coefficient in this subset alone. In 19 studies comparing CAS vs. CEA, the relative risks (95% confidence intervals) of DWI+ and stroke were 3.83 (3.17-4.63, p < 0.00001) and 2.38 (1.44-3.94, p = 0.0007), respectively.

Discussion

This systematic meta-analysis demonstrates a correlation between the occurrence of silent brain infarcts on diffusion-weighted imaging and the risk of clinically manifest stroke in carotid revascularisation procedures.

Conclusion

Our findings strengthen the evidence base for the use of DWI as a surrogate outcome measure for procedural stroke in carotid revascularisation procedures. Further randomised studies comparing treatment effects on DWI lesions and clinical stroke are needed to fully establish surrogacy.

A systematic review and meta-analysis of results of simultaneous bilateral carotid artery stenting

BACKGROUND

Although staged procedures to treat bilateral carotid artery stenosis are mainstream, a growing number of articles on simultaneous bilateral carotid artery stenting (SBCAS) have been published. Thus, this meta-analysis was performed to evaluate the efficacy and safety of SBCAS.

METHODS

The PubMed and Embase databases were searched to identify all studies reporting SBCAS from January 1, 2000, to October 1, 2017. Patients' characteristics, comorbidities, technical success, deaths, and complications were collected and analyzed. Forest plots were drawn with either a random-effects model or fixed-effects model according to their heterogeneities. Publication biases were tested by funnel plots and linear regression test.

RESULTS

Overall, 333 patients with bilateral carotid stenosis in 10 retrospective studies were enrolled in this meta-analysis. The mean age was 67.4 years; 75% of the patients were male, and 85.6% of them were symptomatic. The mean severity of stenosis was 82.1%. The overall technical success rate reached 99.38% (95% confidence interval [CI], 96.58%-100.00%). The pooled incidences of periprocedural complications were as follows: hemodynamic depression, 46.12% (95% CI, 33.16%-59.35%); hyperperfusion syndrome, 3.33% (95% CI, 1.66%-5.55%); stroke, 3.20% (95% CI, 1.59%-5.36%); myocardial infarction (MI), 0.60% (95% CI, 0.00%-1.43%); and death, 1.20% (95% CI, 0.03%-2.38%). The occurrence of a periprocedural primary end point, defined as a combination of any stroke, MI, and death, affected 4.28% (95% CI, 2.37%-6.71%) of patients. For long-term patency, there were too few follow-up results available to evaluate.

CONCLUSIONS

Except for hyperperfusion syndrome, all other periprocedural complications including hemodynamic depression, stroke, and MI were comparable with the literature reporting unilateral carotid artery stenting. However, the analysis was based on retrospective studies. Further studies, including prospective and randomized controlled studies, are needed to confirm these results.

Comparison of Best Medical Management with Carotid Intervention Procedures in the Prevention of Stroke Recurrence in Patients with Symptomatic Internal Carotid Artery Stenosis

Background:

As per the current recommendations, carotid interventional procedures (carotid endarterectomy/carotid artery stenting) are considered superior to medical management in reducing the stroke recurrence in patients with symptomatic extracranial internal carotid artery (ICA) stenosis.

Objective:

The objective of this study is to compare the best medical management with carotid interventional procedures in the prevention of stroke recurrence in the patients with symptomatic extracranial ICA stenosis.

Materials and Methods:

This was a parallel, prospective, two-arm, open-label, observational study. Participants were selected consecutively and prospectively among patients from Outpatient and Inpatient Departments of Neurology at Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India. The study period was from January 2012 to December 2017.

Results:

Of 150 patients with symptomatic extracranial ICA stenosis of ≥50%, 100 preferred best medical management (m = 75, f = 25) and 50 (m = 37, f = 13) opted for carotid intervention. The mean age of the patient cohort was 59.8 ± 12.7. Follow-up was done at regular intervals from 3 months to 1 year. In the medical group, the recurrence occurred in 10 patients; 4 (40%) within 6 months, 5 (50%) within 6–12 months, and 1 (10%) after 1 year. In the intervention group, the recurrence occurred in 6 patients; 5 (83%) within the first 6 months and 1 (17%) within 6–12 months.

Conclusions:

Overall, there was no statistically significant difference in the rate of recurrence between the best medical management and the carotid interventional procedures.

Incidence and Etiology of Microinfarcts in Patients with Ischemic Stroke

BACKGROUND AND PURPOSE

Cerebral microinfarcts (CMI) are associated with intracerebral hemorrhage due to small vessel disease (SVD) in studies not including an ischemic etiologic workup. We aimed to determine their incidence and potential causes in a large ischemic stroke (IS) cohort.

METHODS

Consecutive patients with MRI-confirmed IS within 72 hours of onset were enrolled. Subjects had either single high-risk embolic source (cardioembolic or large vessel disease) or no embolic source. CMIs were classified by their relationship to the primary infarct as within or outside the same vascular territory. White matter hyperintensities (WMH) and microbleeds were markers SVD severity. Multivariable regression tested the association between CMIs and potential etiologies.

RESULTS

We analyzed 946 IS patients, mean age 69 ± 15 years, 46% female. We detected CMI (≤5 mm) on diffusion-weighted imaging in 269 (28%) subjects, 190 (71%) within the vascular territory of the primary infarct. Large-vessel atherosclerosis (P <.001), cardioembolic source (P <.001), higher WMH (P = .032) and lower systolic blood pressure (SBP, P = .024) were independently associated with the presence of CMI. While SBP was associated with CMI in any location (P <.05), WMH was only associated with CMI outside the territory of the primary infarct (P = .033), and large vessel atherosclerosis with CMI within the primary infarct territory (P = .004).

CONCLUSIONS

CMIs occurring within the vascular territory of a larger infarct are more likely embolic, but those occurring outside are probably related to SVD. Our findings suggest a role for SVD in pathogenesis of CMIs and emphasize the importance of etiologic workup to identify alternate etiologies.

Transcranial Doppler Monitoring in Carotid Endarterectomy: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the efficacy of intraoperative transcranial Doppler monitoring in predicting perioperative strokes after carotid endarterectomy (CEA).

METHODS

An electronic search of PubMed, Embase, and Web of Science databases was conducted for studies on transcranial Doppler monitoring in CEA published from January 1970 through September 2015. All titles and abstracts were independently screened on the basis of predetermined inclusion criteria, which included randomized clinical trials and prospective or retrospective cohort reviews, patients who underwent CEA with intraoperative transcranial Doppler monitoring (either middle cerebral artery velocity [MCAV] or cerebral microembolic signals [MES]) and postoperative neurologic assessments up to 30 days after the surgery, and studies including an abstract, published in English on adult humans 18 years and older with a sample size of 50 or greater.

RESULTS

A total of 25articles with a sample population of 4705 patients were analyzed. Among the study patients, 189 developed perioperative strokes. Transcranial Doppler monitoring (either MCAV or MES) showed specificity of 72.7% (95% confidence interval [CI], 61.2%-81.8%) and sensitivity of 56.1% (95% CI, 46.8%-65.0%) for predicting perioperative strokes. Intraoperative MCAV changes during CEA showed strong specificity of 84.1% (95% CI, 74.4%-90.6) and sensitivity of 49.7% (95% CI, 40.6%-58.8) for predicting perioperative strokes.

CONCLUSIONS

Patients with perioperative strokes are 4 times more likely to have had transcranial Doppler changes (either MCAV or MES) during CEA compared to patients without strokes. Simultaneous MCAV and MES monitoring by transcranial Doppler sonography and combined intraoperative monitoring of transcranial Doppler sonography with somatosensory evoked potentials and electroencephalography during CEA to predict perioperative stroke could not be evaluated because of a lack of clinical studies combining these measures.

Complications and Predictors of Hypotension Requiring Vasopressor after Carotid Artery Stenting

A significant controversy exists regarding the clinical impact of hemodynamic depression on major adverse events after carotid artery stenting (CAS). The purpose of this study was to evaluate the incidence, predictors, and clinical significance of hypotension after CAS. A total of 118 cases of carotid artery stenosis were treated with CAS. Hypotension was defined as sustained systolic blood pressure <80 mmHg and requiring intravenous administration of vasopressor to maintain adequate systolic blood pressure after the procedure. Baseline characteristics, procedural characteristics, and periprocedural major adverse events were retrospectively compared between postprocedural hypotension group and non-hypotension group. Morphological and procedural characteristics were not significantly different between the two groups. Periprocedural major adverse events, presence of new ischemic lesions, and number of new ischemic lesions were not significantly different between the two groups (P = 1, P = 0.36, P = 0.68). Hypertension was an independent protective factor (P = 0.037), and use of proximal protection and the distance from carotid bifurcation to maximum stenotic lesion ≤ 10 mm were independent risk factors for developing hypotension after CAS (P = 0.034, P = 0.027). There was no significant relationship between hypotension after CAS and major adverse events in this study. Maintenance of periprocedural adequate cerebral perfusion is thought to be important to prevent ischemic complications due to hypotension after CAS, especially in these cases.

Diagnostic accuracy of somatosensory evoked potential and electroencephalography during carotid endarterectomy

BACKGROUND AND PURPOSE

Perioperative stroke risk following carotid endarterectomy (CEA) is reported to be approximately 2-3%. The diagnostic accuracies of intraoperative EEG and SSEP monitoring during CEA have been studied separately. However, to date, the effectiveness of simultaneous EEG and SSEP monitoring during CEA has only been evaluated in small study populations. This study examined the diagnostic accuracy of combined EEG and SSEP monitoring in a large (N = 1165) patient population.

METHODS

This study included 1165 patients who underwent CEA from 2000 to 2012 at the University of Pittsburgh Medical Center. The sensitivities, specificities, and diagnostic odds ratio of EEG and SSEP monitoring methods were examined separately and together. Receiver operating characteristic curves were plotted to assess sensitivity and specificity of single and combined Intraoperative monitoring (IONM) methods.

RESULTS

Maximum sensitivity was obtained with multimodality monitoring with an IONM change in either EEG or SSEP of 50.00 (95% CI, 30.66-69.34). The specificity of simultaneous EEG and SSEP changes was 93.95 (95% CI, 92.28-95.35%). Maximum area under ROC curve obtained for IONM change in either EEG or SSEP was 0.660 (95% CI, 0.547-0.773, p-value 0.004).

CONCLUSION

The diagnostic accuracy of multimodality IONM during CEA is higher than an approach using single modality IONM. Simultaneous EEG and SSEP monitoring improves the likelihood of detecting periprocedural strokes after CEA. Neuro protective therapies to prevent periprocedural strokes can be based on changes in SSEP and EEG during CEA.

Somatosensory evoked potentials in carotid artery stenting: Effectiveness in ascertaining cerebral ischemic events

Somatosensory evoked potentials (SSEP) have been used in various endovascular procedures and carotid endarterectomy, but to our knowledge no literature deals exclusively with the utility of SSEP in carotid artery stenting (CAS). The purpose of this study was to evaluate the efficacy of SSEP in detecting cerebral ischemic events during CAS. We conducted a prospective study in 35 CAS procedures in 31 patients during an 18month period. Thirty-three patients without near occlusion underwent stenting using dual protection (simultaneous flow reversal and distal filter) combined with blood aspiration, while two patients with near occlusion underwent stenting without dual protection. All 35 patients underwent SSEP monitoring. SSEP were generated by stimulating median and/or tibial nerves and recorded by scalp electrodes. During the aspiration phase post-dilation, seven patients (20%) exhibited SSEP changes with a mean duration of 11.3±8.5minutes (range: 3-25minutes), three of whom later developed minor stroke/transient ischemic attack. Diffusion-weighted imaging showed new lesions in 10 patients (28.6%). Change in SSEP exhibited mean sensitivity of 100% (95% confidence interval, 0.29-1.0) and specificity of 88% (95% confidence interval, 0.71-0.96) in predicting clinical stroke post-CAS. Intra-procedural SSEP change was predictive of post-procedural complications (p=0.005, Fisher's exact test). Longer span of SSEP change was positively correlated with complications (p=0.032, Mann-Whitney test). Intra-procedural SSEP changes are highly sensitive in predicting neurological outcome following CAS. Chances of complications are increased with prolongation of such changes. SSEP allows for prompt intra-procedural ischemia prevention measures and stratification to pursue an aggressive peri-procedural protocol for high risk patients to mitigate neurological deficits.

Mechanism of Procedural Stroke Following Carotid Endarterectomy or Carotid Artery Stenting Within the International Carotid Stenting Study (ICSS) Randomised Trial

OBJECTIVE

To decrease the procedural risk of carotid revascularisation it is crucial to understand the mechanisms of procedural stroke. This study analysed the features of procedural strokes associated with carotid artery stenting (CAS) and carotid endarterectomy (CEA) within the International Carotid Stenting Study (ICSS) to identify the underlying pathophysiological mechanism.

MATERIALS AND METHODS

Patients with recently symptomatic carotid stenosis (1,713) were randomly allocated to CAS or CEA. Procedural strokes were classified by type (ischaemic or haemorrhagic), time of onset (intraprocedural or after the procedure), side (ipsilateral or contralateral), severity (disabling or non-disabling), and patency of the treated artery. Only patients in whom the allocated treatment was initiated were included. The most likely pathophysiological mechanism was determined using the following classification system: (1) carotid-embolic, (2) haemodynamic, (3) thrombosis or occlusion of the revascularised carotid artery, (4) hyperperfusion, (5) cardio-embolic, (6) multiple, and (7) undetermined.

RESULTS

Procedural stroke occurred within 30 days of revascularisation in 85 patients (CAS 58 out of 791 and CEA 27 out of 819). Strokes were predominately ischaemic (77; 56 CAS and 21 CEA), after the procedure (57; 37 CAS and 20 CEA), ipsilateral to the treated artery (77; 52 CAS and 25 CEA), and non-disabling (47; 36 CAS and 11 CEA). Mechanisms of stroke were carotid-embolic (14; 10 CAS and 4 CEA), haemodynamic (20; 15 CAS and 5 CEA), thrombosis or occlusion of the carotid artery (15; 11 CAS and 4 CEA), hyperperfusion (9; 3 CAS and 6 CEA), cardio-embolic (5; 2 CAS and 3 CEA) and multiple causes (3; 3 CAS). In 19 patients (14 CAS and 5 CEA) the cause of stroke remained undetermined.

CONCLUSION

Although the mechanism of procedural stroke in both CAS and CEA is diverse, haemodynamic disturbance is an important mechanism. Careful attention to blood pressure control could lower the incidence of procedural stroke.

Carotid Disease Management: Surgery, Stenting, or Medication

Internal carotid artery stenosis accounts for about 7-10 % of ischemic strokes. Conventional risk factors such as aging, hypertension, diabetes mellitus, and smoking increase the risk for carotid atherosclerosis. All patients with carotid stenosis should receive aggressive medical therapy. Carotid revascularization with either endarterectomy or stenting can benefit select patients with severe stenosis. New clinical trials will examine the contemporary role of carotid revascularization relative to optimal medical therapy.

Management of extracranial carotid artery disease

Stroke is the third leading cause of death in developed nations. Up to 88% of strokes are ischemic in nature. Extracranial carotid artery atherosclerotic disease is the third leading cause of ischemic stroke in the general population and the second most common nontraumatic cause among adults younger than 45 years. This article provides comprehensive, evidence-based recommendations for the management of extracranial atherosclerotic disease, including imaging for screening and diagnosis, medical management, and interventional management.

Anatomical risk factors for ischemic lesions associated with carotid artery stenting

The purpose of this study was to investigate the anatomical risk factors for ischemic lesions detected by diffusion-weighted imaging (DWI) associated with carotid artery stenting (CAS). DWI was performed within four days after CAS in 50 stenotic lesions between January 2008 and September 2013. We retrospectively analyzed the correlation between the anatomical factors and ischemic lesions associated with CAS. Post-procedural DWI revealed new ischemic lesions after 24 (48%) of the 50 CAS procedures. All three patients with common carotid artery tortuosity, defined as the presence of severe angulation (less than 90 degrees) in the common carotid artery, developed new ischemic lesions. However, there were no significant differences between the patients with and without tortuosity, likely due to the small number of cases. Meanwhile, seven of eight patients with internal carotid artery tortuosity, defined as the presence of severe angulation (less than 90 degrees) in the cervical segment of the internal carotid artery, developed new ischemic lesions. A multivariate analysis showed internal carotid artery tortuosity (odds ratio: 11.84, 95% confidence interval: 1.193-117.4, P= 0.035) to be an independent risk factor for the development of ischemic lesions associated with CAS. Anatomical factors, particularly severe angulation of the internal carotid artery, have an impact on the risk of CAS. The indications for CAS should be carefully evaluated in patients with these factors.