Relationship Between Blood Pressure and Stroke Recurrence in Patients With Intracranial Arterial Stenosis

Higher Stroke Risk with Lower Blood Pressure in Hemodynamic Vertebrobasilar Disease: Analysis from the VERiTAS Study

BACKGROUND

Despite concerns regarding hypoperfusion in patients with large-artery occlusive disease, strict blood pressure (BP) control has become adopted as a safe strategy for risk reduction of stroke. We examined the relationship between BP control, blood flow, and risk of subsequent stroke in the prospective Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) study.

METHODS

The VERiTAS study enrolled patients with recent vertebrobasilar (VB) transient ischemic attack or stroke and ≥50% atherosclerotic stenosis or occlusion of vertebral or basilar arteries. Hemodynamic status was designated as low or normal based on quantitative magnetic resonance angiography. Patients underwent standard medical management and follow-up for primary outcome event of VB territory stroke. Mean BP during follow-up (<140/90 versus ≥140/90 mm Hg) and flow status were examined relative to subsequent stroke risk using Cox proportional hazards analysis.

RESULTS

The 72 subjects had an average of 3.8 ± 1.2 BP recordings over 20 ± 8 months of follow-up; 39 (54%) had mean BP of<140/90 mm Hg. The BP groups were largely comparable for baseline demographics, risk factors, and stenosis severity. Comparing subgroups stratified by BP and hemodynamic status, we found that patients with both low flow and BP <140/90 mm Hg (n = 10) had the highest risk of subsequent stroke, with hazard ratio of 4.5 (confidence interval 1.3-16.0, P = .02), compared with the other subgroups combined.

CONCLUSIONS

Among a subgroup of patients with VB disease and low flow, strict BP control (BP <140/90) may increase the risk of subsequent stroke.

Frequency, Risk Factors, and Outcome of Coexistent Small Vessel Disease and Intracranial Arterial Stenosis: Results From the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) Trial

IMPORTANCE

Intracranial arterial stenosis (ICAS) and small vessel disease (SVD) may coexist. There are limited data on the frequency and risk factors for coexistent SVD and the effect of SVD on stroke recurrence in patients receiving medical treatment for ICAS.

OBJECTIVE

To investigate the frequency and risk factors for SVD and the effect of SVD on stroke recurrence in patients with ICAS.

DESIGN, SETTING, AND PARTICIPANTS

A post hoc analysis of the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) study, a prospective, multicenter clinical trial. Among 451 participants, 313 (69.4%) had baseline brain magnetic resonance imaging scans read centrally for SVD that was defined by any of the following: old lacunar infarction, grade 2 to 3 on the Fazekas scale (for high-grade white matter hyperintensities), or microbleeds. Patient enrollment in SAMMPRIS began November 25, 2008, and follow-up ended on April 30, 2013. Data analysis for the present study was performed from May 13, 2014, to July 29, 2015.

MAIN OUTCOMES AND MEASURES

Risk factors in patients with vs without SVD and the association between SVD and other baseline risk factors with any ischemic stroke and ischemic stroke in the territory of the stenotic artery determined using proportional hazards regression.

RESULTS

Of 313 patients, 155 individuals (49.5%) had SVD noted on baseline magnetic resonance imaging. Variables that were significantly higher in patients with SVD, reported as mean (SD), included age, 63.5 (10.5) years (P < .001), systolic blood pressure, 149 (22) mm Hg (P < .001), glucose level, 130 (50) mg/dL (P = .03), and lower Montreal Cognitive Assessment scores (median, ≥24 [interquartile range, 20-26]; P = .02).Other significant variables were the number of patients with diabetes mellitus (88 of 155 [56.8%]; P = .003), coronary artery disease (46 [29.7%]; P = .004), stroke before the qualifying event (59 [38.1%]; P < .001), old infarct in the territory of the stenotic intracranial artery (88 [56.8%]; P < .001), and receiving antithrombotic therapy at the time of the qualifying event (109 [70.3%]; P = .005). The association between SVD and any ischemic stroke was nearly significant in the direction of a higher risk (18 [23.7%]); P = .07) for patients with SVD. On bivariate analysis, SVD was not associated with an increased risk on multivariable analyses (hazard ratio, 1.7 [95% CI, 0.8-3.8]; P = .20). In addition, SVD was not associated with an increased risk of stroke in the territory on either bivariate or multivariable analyses.

CONCLUSIONS AND RELEVANCE

Although SVD is common in patients with ICAS, the presence of SVD on baseline magnetic resonance imaging is not independently associated with an increased risk of stroke in patients with ICAS.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00576693.

H-Type Hypertension and C Reactive Protein in Recurrence of Ischemic Stroke

Hypertension with high homocysteine (HHcy) (H-type hypertension) and C reactive protein (CRP) can increase the incidence of ischemic stroke. However, it is not clear whether recurrent ischemic stroke (RIS) is related to H-type hypertension and CRP. The present study investigated the correlation of H-type hypertension and CRP level with RIS. Totally, 987 consecutive patients with acute ischemic stroke were recruited in a teaching hospital in Henan province, China during March 2014 to March 2015. The demographic and clinical characteristics and blood biochemical parameters of patients were analyzed. Elevated levels of CRP and homocysteine (Hcy) were defined as >8.2 mg/L and 10 μmol/L, respectively. Among the 987 patients, 234 were RIS. Thirty-eight percent of RIS patients had elevated CRP level and 91.5% of RIS patients had HHcy. In multivariate analysis, adjusted odds ratio (OR) of RIS in patients aged ≥60 years was 1.576 (95% CI: 1.125–2.207), in male patients 1.935 (95% CI: 1.385–2.704), in patients with diabetes 1.463 (95% CI: 1.037–2.064), CRP levels 1.013 (95% CI: 1.006–1.019), simple hypertension 3.370 (95% CI: 1.15–10.183), and H-type hypertension 2.990 (95% CI: 1.176–7.600). RIS was associated with older age, male, diabetes, H-type hypertension and CRP. Controlling H-type hypertension and CRP level may reduce the risk of RIS.

The contemporary management of intracranial atherosclerotic disease

Intracranial atherosclerotic disease is the most common cause of cerebral vasculopathy and an important stroke etiology worldwide, with a higher prevalence in Asian, Hispanic and African ethnicities. Symptomatic intracranial atherosclerotic disease portends a recurrent stroke risk as high as 18% at one year. The key to secondary prevention is an understanding of the underlying stroke mechanism and aggressive control of conventional cardiovascular risks. Contemporary treatment includes antiplatelet therapy, optimal glycemic and blood pressure control, statin therapy and lifestyle modifications. For patients with high-grade (70-99%) symptomatic steno-occlusion, short-term dual antiplatelet therapy with aspirin and clopidogrel followed by life-long single antiplatelet therapy may reduce the recurrent risk. Current evidence does not advocate percutaneous transluminal angioplasty and stenting as an initial treatment. External counterpulsation, encephaloduroarteriosynangiosis and remote limb ischemic preconditioning are treatments under investigation. Future studies should aim at predicting patients prone to recurrence despite of medical therapies and testing the efficacy of emerging therapies.

Rigorous anaesthesia management protocol for patients with intracranial arterial stenosis: a prospective controlled-cohort study

OBJECTIVES

Reducing variability is integral in quality management. As part of the ongoing Encephaloduroarteriosynangiosis Revascularisation for Symptomatic Intracranial Arterial Stenosis (ERSIAS) trial, we developed a strict anaesthesia protocol to minimise fluctuations in patient parameters affecting cerebral perfusion. We hypothesise that this protocol reduces the intraoperative variability of targeted monitored parameters compared to standard management.

DESIGN

Prospective cohort study of patients undergoing encephaloduroarteriosynangiosis surgery versus standard neurovascular interventions. Patients with ERSIAS had strict perioperative management that included normocapnia and intentional hypertension. Control patients received regular anaesthetic standard of care. Minute-by-minute intraoperative vitals were electronically collected. Heterogeneity of variance tests were used to compare variance across groups. Mixed-model regression analysis was performed to establish the effects of treatment group on the monitored parameters.

SETTING

Tertiary care centre.

PARTICIPANTS

24 participants: 12 cases (53.8 years ± 16.7 years; 10 females) and 12 controls (51.3 years ± 15.2 years; 10 females). Adults aged 30-80 years, with transient ischaemic attack or non-disabling stroke (modified Rankin Scale <3) attributed to 70-99% intracranial stenosis of the carotid or middle cerebral artery, were considered for enrolment. Controls were matched according to age, gender and history of neurovascular intervention.

MAIN OUTCOME MEASURES

Variability of heart rate, mean arterial blood pressure (MAP), systolic blood pressure and end tidal CO2 (ETCO2) throughout surgical duration.

RESULTS

There were significant reductions in the intraoperative MAP SD (4.26 vs 10.23 mm Hg; p=0.007) and ETCO2 SD (0.94 vs 1.26 mm Hg; p=0.05) between the ERSIAS and control groups. Median MAP and ETCO2 in the ERSIAS group were higher (98 mm Hg, IQR 23 vs 75 mm Hg, IQR 15; p<0.001, and 38 mm Hg, IQR 4 vs 32 mm Hg, IQR 3; p<0.001, respectively).

CONCLUSIONS

The ERSIAS anaesthesia protocol successfully reduced intraoperative fluctuations of MAP and ETCO2. The protocol also achieved normocarbia and the intended hypertension.

TRIAL REGISTRATION NUMBER

NCT01819597; Pre-results.

Hemodynamic Impact of Systolic Blood Pressure and Hematocrit Calculated by Computational Fluid Dynamics in Patients with Intracranial Atherosclerosis

OBJECTIVE

Success in clinical trials of intracranial atherosclerosis (ICAS) is related to accurate identification of high-risk patients. Noninvasive computational fluid dynamics (CFD) of stenotic lesions may enhance therapeutic decision-making. We determined whether physiologic parameters change downstream cerebral hemodynamics in patients with ICAS.

METHODS

Consecutive ICAS patients who underwent both CT angiography (CTA) and digital subtraction angiography were enrolled. CFD models were made using CTA source images. Inlet boundary conditions were defined using three ranges of systolic blood pressure (BP) (109.2, 158, and 225 mmHg) and hematocrit (27.3, 40.2, and 48.8). Ratios of pressure, shear strain rates (SSR), and flow velocity across the lesion were calculated using CFD simulations. A linear mixed model was used for the statistical analysis of repeated simulations.

RESULTS

Among the 56 patients, 32 had moderate stenosis (50-69%) and 24 had severe stenosis (70-99%). A linear mixed model revealed that the ratio of pressure was predicted by systolic BP and stenosis group interaction (P = .036). These pressure decreases were associated with systolic BP (P < .001) and stenosis group (P < .001), but not with hematocrit (P = .337). Post-hoc analysis revealed that pressure decreases were more profound in the severe stenosis than the moderate stenosis group when comparing high and low systolic BP (P = .0108). Ratios of SSR and velocity were only associated in the stenosis group.

CONCLUSIONS

Our study showed that systolic BP along with the degree of stenosis was associated with pressure decreases across stenotic lesions. Physiologic conditions may superimpose further changes in post-stenotic or downstream blood flow.

Do Patient Characteristics Explain the Differences in Outcome Between Medically Treated Patients in SAMMPRIS and WASID?

BACKGROUND AND PURPOSE

The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) medical group had a much lower primary end point rate than predicted from the preceding Warfarin Aspirin Symptomatic Intracranial Disease (WASID) trial. This result has been attributed to the aggressive medical therapy used in SAMMPRIS, but an alternative hypothesis is that SAMMPRIS patients were at lower risk. We undertook analyses to evaluate these competing hypotheses.

METHODS

Using proportional hazards regression, we compared the SAMMPRIS primary end point between SAMMPRIS medical patients and WASID patients meeting the same qualifying criteria adjusted for confounding baseline characteristics.

RESULTS

The unadjusted comparison of the SAMMPRIS primary end point showed a significantly higher risk for WASID patients (P=0.009, logrank test) with 12 month Kaplan-Meier estimates of 21.9% in WASID and 12.6% in SAMMPRIS and hazard ratio 1.9 (95% confidence interval =1.2-3.0). The analyses identified the following confounding factors that varied between the studies and that conferred a higher risk: lack of statin use at enrollment (hazard ratio =1.8, 95% confidence interval =1.1-2.9, P=0.027) that was more prevalent among WASID patients (39% versus 14%, P<0.0001) and prior infarcts in the territory of the symptomatic vessel (hazard ratio =1.8, 95% confidence interval =1.1-2.9, P=0.023) that was more prevalent among SAMMPRIS patients (34% versus 22%, P=0.015).The hazard ratio for WASID versus SAMMPRIS adjusted for these 2 characteristics was 1.9 (95% confidence interval =1.1-3.2).

CONCLUSIONS

After adjustment for confounding baseline characteristics, WASID patients had an almost 2-fold higher risk of the SAMMPRIS primary end point, which supports the hypothesis that the lower rate of the primary end point in the medical arm of SAMMPRIS compared with WASID patients was as a result of the aggressive medical management used in SAMMPRIS.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00576693.

Evidence for Cerebral Hemodynamic Measurement-based Therapy in Symptomatic Major Cerebral Artery Disease

In patients with atherosclerotic internal carotid artery or middle cerebral artery occlusive disease, chronic reduction in cerebral perfusion pressure (chronic hemodynamic compromise) increases the risk of ischemic stroke and can be detected by directly measuring hemodynamic parameters. However, strategies for selecting treatments based on hemodynamic measurements have not been clearly established. Bypass surgery has been proven to improve hemodynamic compromise. However, the benefit of bypass surgery for reducing the stroke risk in patients with hemodynamic compromise is controversial. The results of the two randomized controlled trials were inconsistent. Hypertension is a major risk factor for stroke, and antihypertensive therapy provides general benefit to patients with symptomatic atherosclerotic major cerebral artery disease. However, the benefit of strict control of blood pressure for reducing the stroke risk in patients with hemodynamic compromise is a matter of debate. The results of the two observational studies were different. We must establish strategies for selecting treatments based on hemodynamic measurements in atherosclerotic major cerebral artery disease.

High Blood Pressure Increases the Risk of Poor Outcome at Discharge and 12-month Follow-up in Patients with Symptomatic Intracranial Large Artery Stenosis and Occlusions: Subgroup analysis of the CICAS Study

Aims

The purpose of this study was to discuss the relationship between blood pressure and prognosis of patients with symptomatic intracranial arterial stenosis.

Methods

Data on 2426 patients with symptomatic intracranial large artery stenosis and occlusion who participated in the Chinese Intracranial Atherosclerosis (CICAS) study were analyzed. According to the JNC 7 criteria, blood pressure of all patients was classified into one of the four subgroups: normal, prehypertension, hypertension stage I, and hypertension stage II. Poor outcomes were defined as death and functional dependency (mRS 3‐5) at discharge or at 1 year.

Results

For patients with intracranial stenosis of 70% to 99%, the rate of poor outcome at discharge was 19.3%, 23.5%, 26.8%, and 39.8% (P = 0.001) for each blood pressure subgroup. For patients with intracranial large artery occlusion, the rates were 17.6%, 22.1%, 29.5%, and 49.8%, respectively (P < 0.0001). The rate of poor outcome at 12‐month follow‐up was 12.6%, 15.3%, 28.5%, and 27.9% (P = 0.0038) in patients with stenosis of 70% to 99% for each blood pressure subgroup and 11.6%, 21.5%, 23.9%, 35.1% (P < 0.0001) in patients with occlusion.

Conclusions

For patients with severe intracranial arterial stenosis or occlusion, higher hypertension stages are associated with an increased risk of poor outcome at discharge and 12‐month follow‐up.

Prothrombotic risk factors and antithrombotic therapy in children with ischemic stroke

OBJECTIVE

Congenital and acquired prothrombotic disorders have been highlighted in a recent series of cerebrovascular stroke (CVS), with a controversial role in pathogenesis. The aim is to study some prothrombotic risk factors [activated protein C (APC) resistance, von Willebrand factor (vWF), anticardiolpin (ACL) antibodies and plasma homocysteine] in children with ischemic stroke, and to evaluate the role of aspirin and low molecular weight heparin (LMWH) in its management in relation to outcome.

METHODS

A total of 37 cases aged from 1 month to 15 years ( mean ± standard deviation 26.2 ± 35.7 months), diagnosed as ischemic stroke (>24 hours) were recruited. Complete blood count, prothrombin time and concentration, partial thromboplastin time, serum electrolytes, random blood sugar, C-reactive protein, electrocardiogram and echocardiography were done. Levels of APC resistance, vWF, ACL antibodies [immunoglobulin G (IgG) and immunoglobulin M (IgM)] and plasma homocysteine were estimated. A total of 25 cases received aspirin 3-5 mg /kg/d and 12 patients received LMWH as initial dose at 75 international units (IU)/kg subcutaneously (SC) then 10-25 IU/kg/day for 15 days in a nonrandomized fashion.

RESULTS

The levels of APC resistance, vWF, ACL antibodies (IgG and IgM) and plasma homocysteine were significantly higher in stroke cases than in controls. There was no significant difference between cases treated with aspirin and those with LMWH in all prothrombotic factors. Significant positive correlations were found between vWF and ACL antibodies (IgG and IgM) levels before treatment. Significant decrease in cognitive function was detected between cases treated with LMWH and those treated with aspirin.

CONCLUSION

Ischemic CVS in children is multifactorial. Thrombophilia testing should be performed in any child with CVS. Early use of aspirin improves the prognosis and has less effect on cognitive function.

Hypertension criterion for stroke prevention--to strengthen the principle of individualization in guidelines

The diagnosis of hypertension, as recommended by most guidelines, is determined by systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure ≥90 mm Hg. A threshold-based definition of hypertension, however, ignores sex and age, pathophysiology, and disparities in patient-specific conditions. Moreover, the harmful effects of hypertension-induced target organ damage cannot be ignored. Although the principle of individualization for hypertension management is recommended, especially for stroke prevention, how to practice it in a clinical setting has not been clearly elaborated. Therefore, we put forward a proposal for individualized hypertension management incorporating target organ damage, the main harmful effect of hypertension. We propose that hypertension should be diagnosed when an individual's blood pressure exceeds some difference from their own baseline in young adulthood, accompanied by any hypertension-induced target organ damage, confirmed by various detection methods. Application of this proposal to stroke prevention will hopefully strengthen the principle of individualized hypertension management.

Clinical significance of the circle of Willis in intracranial atherosclerotic stenosis

Introduction

The effectiveness of a scoring system based on the circle of Willis for evaluations of collateral circulation was studied in patients with intracranial atherosclerotic stenosis.

Methods

Eighty-three patients who underwent medical or endovascular treatment for symptomatic and severe intracranial atherosclerotic stenosis were enrolled in the study. Clinical profiles, status of the circle of Willis (poor and good integrity group), and clinical outcomes were analyzed. Primary endpoints were: (1) symptomatic ischemic or hemorrhagic stroke within 30 days; and (2) recurrent transient ischemic attack or ischemic stroke beyond 30 days.

Results

The estimated rates of the primary endpoint at 1 and 2 years after treatment were 8.5% and 11.4% in the medical group and 7.0% and 9.7% in the endovascular group, respectively. A primary endpoint event after medical treatment was only identified in patients with poor integrity of the circle of Willis (p=0.059). In patients with poor integrity of the circle of Willis, previous antiplatelet medication before initial presentation (p=0.026) and hypertension (p=0.006) were more prevalent. During the follow-up period, complete arterial occlusion was identified in 9 patients. The circle of Willis score of the patients with complete arterial occlusion was 1.33±1.52 in the fatal stroke group (n=3) and 3.20±1.64 in the asymptomatic group (n=6, p=0.099).

Conclusions

If patients have poor integrity of the circle of Willis, the risk of recurrent stroke may be increased. Such patients appear to be good candidates for endovascular treatment.

Blood pressure management in stroke: Five new things

Hypertension is a major modifiable risk factor for stroke, with an estimated 51% of stroke deaths being attributable to high systolic blood pressure globally.^1,2 The management of hypertension in stroke is determined by timing, the type of stroke, use of thrombolysis, concurrent medical conditions, and pharmacologic variables. We highlight the details of elevated blood pressure management in the hyperacute/acute, subacute, and chronic stages of ischemic stroke and intracerebral hemorrhage.

Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

The case for angioplasty in patients with symptomatic intracranial atherosclerosis

Intracranial atherosclerotic disease (ICAD) is likely the most common cause of stroke worldwide and remains highly morbid even with highly monitored medical therapy. Recent results of the SAMMPRIS trial, which randomized patients to stenting plus aggressive medical management versus aggressive medical management alone have shown that additional treatment of intracranial atherosclerotic lesions with the Wingspan stent is inferior to aggressive medical management alone. In light of these results, there has been renewed interest in angioplasty alone to treat symptomatic ICAD. This article will briefly review the natural history of ICAD and discuss the possible future for endovascular treatment of ICAD with primary intracranial angioplasty in appropriately selected patients.

High blood pressure on admission in relation to poor outcome in acute ischemic stroke with intracranial atherosclerotic stenosis or occlusion

BACKGROUND

Intracranial atherosclerotic stenosis is common in Asian, black, and Hispanic individuals. However, the management of blood pressure (BP) in the setting of acute stage in these patients is controversial. The present study aims to explore the relationship between BP on admission and outcomes in acute ischemic stroke patients with intracranial atherosclerotic stenosis or occlusion.

METHODS

We prospectively registered consecutive cases of acute ischemic stroke from September 01, 2009, to August 31, 2011. Patients with severe intracranial stenosis or occlusion were included. Death or disability was followed up at the end of the third month. The multivariate logistic regression model was used to analyze the relationship between BP on admission and clinical outcomes.

RESULTS

We included 215 cases, which accounted for 22.7% (215 of 946) of the total registered cases. The mean age was 60.44±13.23 years. The median time of symptoms onset to admission was 72 hours (2-270 hours). Patients with systolic blood pressure (SBP) of 120-159 mm Hg or diastolic BP of 70-89 mm Hg had the lowest death or disability. After adjustment of confounders, SBP of 160 mm Hg or more on admission was the independent predictor of death or disability at the third month (relative risk [RR], 2.89; 95% confidence interval [CI], 1.20-6.91). SBP less than 120 mm Hg on admission had a trend of increasing death or disability (RR, 1.96; 95% CI, .60-6.33).

CONCLUSIONS

Higher BP on admission was associated with an increased risk of death or disability in patients with symptomatic intracranial artery stenosis or occlusion. It is reasonable that further studies on the effects of BP lowering in acute stroke include these patients.

Risk factor management for stroke prevention

PURPOSE OF REVIEW

This review focuses on the recommendations for management of hypertension, dyslipidemia, diabetes mellitus, diet, physical activity, and lifestyle choices commonly encountered in neurologic practice. Specific studies, including those relevant to lipid targets, blood pressure targets, and adherence to medications after stroke, are reviewed.

RECENT FINDINGS

In addition to traditional risk factors such as hypertension, dyslipidemia, and diabetes mellitus, this review discusses sleep apnea, diet, physical activity, and other novel risk factors that are potentially modifiable. Recent studies confirm that pharmacologic strategies to achieve aggressive targets for lipid and blood pressure lowering have significant impact on recurrent stroke risk.

SUMMARY

Optimal secondary prevention strategies can prevent as much as 80% of all recurrent strokes.

Influence of cognitive impairment on the management of ischaemic stroke

BACKGROUND

Because of ageing of the population, it is more and more frequent to treat ischaemic stroke patients with pre-stroke cognitive impairment (PSCI). Currently, there is no specific recommendation on ischaemic stroke management in these patients, both at the acute stage and in secondary prevention. However, these patients are less likely to receive treatments proven effective in randomised controlled trials, even in the absence of contra-indication.

OBJECTIVE

To review the literature to assess efficacy and safety of validated therapies for acute ischaemic stroke and secondary prevention in PSCI patients.

RESULTS

Most randomised trials did not take into account the pre-stroke cognitive status. The few observational studies conducted at the acute stage or in secondary prevention, did not provide any information that the benefit could be either lost or replaced by harm in the presence of PSCI.

CONCLUSIONS

There is no reason not to treat ischaemic stroke patients with PSCI according to the currently available recommendations for acute management and secondary prevention. Further observational studies are needed and pre-stroke cognition should be taken into account in future stroke trials.

Intracranial atherosclerotic disease

Atherosclerotic disease of the intracranial arteries is responsible for at least 10% of ischaemic strokes worldwide. Symptomatic disease has been extensively studied in the past few years, using diagnostic methods including multi-slice computed tomography and high resolution magnetic resonance imaging. A literature search was performed using PubMed and OvidSP between 1984 and May 2013. Variations of the terms 'intracranial atherosclerosis' plus 'ischemic stroke', 'plaque', 'morphology', 'imaging' were used and a combination of them. The reference lists of identified articles were also consulted for additional references. Amongst symptomatic patients the prevalence of intracranial atherosclerotic disease is around 10%, depending on race ethnicity, and the diagnosis requires the presence of ≥50% stenosis in the territory of the symptomatic vessel in a patient with stroke or transient ischaemic attack. The prognosis of intracranial atherosclerotic disease related stroke is poor. Although risk factor control can lead to a better outcome of intracranial atherosclerotic disease related strokes, the significance of asymptomatic disease is still a matter of debate.

Lower stroke risk with lower blood pressure in hemodynamic cerebral ischemia

OBJECTIVE

To determine whether strict blood pressure (BP) control is the best medical management for patients with symptomatic carotid artery occlusion and hemodynamic cerebral ischemia.

METHODS

In this prospective observational cohort study, we analyzed data from 91 participants in the nonsurgical group of the Carotid Occlusion Surgery Study (COSS) who had recent symptomatic internal carotid artery occlusion and hemodynamic cerebral ischemia manifested by ipsilateral increased oxygen extraction fraction. The target BP goal in COSS was ≤130/85 mm Hg. We compared the occurrence of ipsilateral ischemic stroke during follow-up in the 41 participants with mean BP ≤130/85 mm Hg to the remaining 50 with higher BP.

RESULTS

Of 16 total ipsilateral ischemic strokes that occurred during follow-up, 3 occurred in the 41 participants with mean follow-up BP of ≤130/85 mm Hg, compared to 13 in the remaining 50 participants with mean follow-up BP >130/85 mm Hg (hazard ratio 3.742, 95% confidence interval 1.065-13.152, log-rank p = 0.027).

CONCLUSION

BPs ≤130/85 mm Hg were associated with lower subsequent stroke risk in these patients.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that control of hypertension ≤130/85 mm Hg is associated with a reduced risk of subsequent ipsilateral ischemic stroke in patients with recently symptomatic carotid occlusion and hemodynamic cerebral ischemia (increased oxygen extraction fraction).

Atherosclerotic intracranial arterial stenosis: risk factors, diagnosis, and treatment

Intracranial atherosclerosis is one of the most common causes of stroke worldwide and is associated with a high risk of recurrent stroke. New therapeutic approaches to treat this high-risk disease include dual antiplatelet treatment, intensive management of risk factors, and endovascular therapy. Early data from randomised trials indicate that aggressive medical therapy is better than stenting for prevention of recurrent stroke in high-risk patients with atherosclerotic stenosis of a major intracranial artery. Nevertheless, there are subgroups of patients who remain at high risk of stroke despite aggressive medical therapy. Further research is needed to identify these high-risk subgroups and to develop more effective treatments. Non-invasive vascular imaging methods that could be used to identify high-risk patients include fractional flow on magnetic resonance angiography (MRA), quantitative MRA, and high-resolution MRI of the atherosclerotic plaque. Alternative therapies to consider for future clinical trials include angioplasty alone, indirect surgical bypass procedures, ischaemic preconditioning, and new anticoagulants (direct thrombin or Xa inhibitors).

Antithrombotic selection and risk factor management in ischemic stroke and transient ischemic attack

In addition to appropriate antithrombotic therapy, the identification and treatment of modifiable ischemic stroke risk factors can reduce the likelihood of recurrent stroke. Neurosurgeons should be knowledgeable of the specific risk factors and general recommendations for ischemic stroke, as they may play a significant role in the management options for patients with intracranial and extracranial atherosclerotic disease. The authors of this article review the indications for and selection of antithrombotics in patients with cerebral ischemia. In addition, the identification and secondary prevention of select risk factors are discussed.

Impaired perfusion modifies the relationship between blood pressure and stroke risk in major cerebral artery disease

OBJECTIVE

Blood pressure (BP) lowering may increase stroke risk in patients with symptomatic major cerebral artery disease and impaired perfusion. To investigate the relationships among BP, impaired perfusion and stroke risk.

METHODS

We retrospectively analysed data from 130 non-disabled, medically treated patients with either symptomatic extracranial carotid occlusion or intracranial stenosis or occlusion of the carotid artery or middle cerebral arteries. All patients had baseline haemodynamic measurements with (15)O-gas positron emission tomography and were followed for 2 years or until stroke recurrence or death.

RESULTS

There was a negative linear relationship between systolic BP (SBP) and risk of stroke in the territory of the diseased artery. The 2-year incidence of ischaemic stroke in the territory in patients with normal SBP (<130 mm Hg, 5/32 patients) was significantly higher than in patients with high SBP (2/98, p<0.005). Multivariate analysis revealed that normal SBP and impaired perfusion were independently associated with increased risk of stroke in the previously affected territory, while risk of stroke elsewhere was positively correlated with SBP. Overall, high total stroke risk was observed at lower BP in patients with impaired perfusion and at higher BPs in patients without (interaction, p<0.01). Overall, the relationship between SBP and total stroke recurrence was J-shaped.

CONCLUSIONS

Impaired perfusion modified the relationship between blood pressure and stroke risk, although this study had limitations including the retrospective analysis, the potentially biased sample, the small number of critical events and the fact that BP was measured only as a snapshot in clinic.

The phenotype of infiltrating macrophages influences arteriosclerotic plaque vulnerability in the carotid artery

BACKGROUND

Proinflammatory (M1) macrophages and anti-inflammatory (M2) macrophages have been identified in atherosclerotic plaques. While these macrophages have been speculated to be related to plaque vulnerability, there are limited studies investigating this relationship. Therefore, we examined the association between macrophage phenotype (M1 versus M2) and plaque vulnerability and clinical events.

METHODS

Patients undergoing carotid endarterectomy received an ultrasound of the carotid artery before surgery. Plaques were processed for analysis by immunohistochemistry, Western blotting, and real-time polymerase chain reaction studies. Medical history and clinical data were obtained from medical records.

RESULTS

Patients were divided into 2 groups: those suffering from acute ischemic attack (symptomatic, n = 31) and those that did not present with symptoms (asymptomatic, n = 34). Ultrasound analysis revealed that plaque vulnerability was greater in the symptomatic group (P= .033; Chi-square test). Immunohistochemistry revealed that plaques from the symptomatic group had a greater concentration of M1 macrophages (CD68-, CD11c-positive) while plaques from the asymptomatic group had more M2 macrophages (CD163-positive). This observation was confirmed by Western blotting. Characterization by real-time polymerase chain reaction studies revealed that plaques from the symptomatic group had increased expression of the M1 markers CD68 and CD11c, as well as monocyte chemoattractive protein-1, interleukin-6, and matrix metalloproteinase-9. In addition, more M1 macrophages expressed in unstable plaques were defined by ultrasound analysis, while more M2 macrophages were expressed in stable plaques.

CONCLUSIONS

Our data show that M1 macrophage content of atherosclerotic plaques is associated with clinical incidence of ischemic stroke and increased inflammation or fibrinolysis. We also show the benefits of using ultrasound to evaluate vulnerability in the plaques.

A Comparison of Stent Implant versus Medical Treatment for Severe Symptomatic Intracranial Stenosis: A Controlled Clinical Trial

Background

Atherosclerotic stenosis of the major intracranial arteries is the most common cause of ischemic stroke. There are limited treatments for severe intracranial stenosis, and stent placement versus medical treatment remains controversial. The aim of this study was to compare functional outcomes of these two modalities in patients with severe symptomatic intracranial stenosis.

Methods

At a single center, between 2008 and 2011, patients with angiographically demonstrated severe (70–90%) symptomatic intracranial atherosclerosis were divided into two groups: group A, which received only medical treatment, and group B, which underwent endovascular stent implant treatment. The severity and location of the stenosis was determined by digital subtraction angiography and the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial criteria in all patients. The exclusion criteria were: specific causes other than atherosclerosis, such as artery dissection, fibromuscular dysplasia, vasculitis, radiation and intracranial hemorrhage, focal neurological deficit that did not correlate to internal carotid artery or middle cerebral artery stenosis. All procedures were done under light anesthesia. Technical success was defined as the reduction of stenosis to <30% with complete enveloping of the lesion after the procedure. Early and late adverse events and functional outcomes were compared between the groups using the modified Rankin Scale (mRS).

Results

Overall, 63 patients (29 in group A and 34 in group B) were evaluated and followed for a mean period of 15.22 months (range 6–25). The technical success rate was 97% in a total of 34 stents in 34 patients. There was no difference between the early (within 30 days) adverse event rates of the two groups. The median follow-up duration for the stent implant patients was 15 months (range 6–25), and for the medically treated cohort it was 14 months (range 8–25). The re-stenosis rate was 5.8% and the total number of late (>30 days) adverse events, including stroke, myocardial infarction and death, was 1 (2.9%) and 6 (20.7%) in the stent implant and medical groups, respectively (p = 0.042). The stent implant group had significantly better favorable functional outcomes according to the mRS than the medical group (93.9 vs. 63.0%). The cumulative secondary adverse event-free survival was significantly lower in the stent implant group.

Conclusion

Stent implants can be considered more durable and safe for patients with symptomatic severe stenosis of the internal carotid artery or middle cerebral artery, despite optimal medical therapy. Randomized, multicenter trials are required to confirm these results.

Symptomatic intracranial arterial disease: incidence, natural history, diagnosis, and management

Symptomatic intracranial arterial disease is associated with a high rate of recurrent ischemic events. The management of this condition is controversial, with some advocating medical therapy as a sole means of treatment and others recommending endovascular therapy in addition to best medical management. In rare cases, surgical intervention is considered. A thorough review of the available literature was performed, and treatment recommendations based on these data are provided.

Current diagnosis and management of symptomatic intracranial atherosclerotic disease

PURPOSE OF REVIEW

Intracranial atherosclerotic disease (IAD) is likely the most common cause of stroke world-wide and is associated with a very high risk of recurrence. It results in cerebral ischemia due to a variety of mechanisms, including artery-to-artery embolism, hemodynamic failure, and occlusion of penetrating arteries. New imaging modalities focused on physiological consequences of IAD have become available and recent treatment trials have been completed.

RECENT FINDINGS

We review the traditional imaging modalities, emphasizing the advantages and limitations of each method, and discuss the novel physiological approaches that interrogate physiological process to indicate specific mechanisms of ischemia. These allow deeper understanding of the pathophysiological processes that underlie IAD-related ischemia. The key findings of recent therapeutic trials are reviewed, including the landmark randomized studies showing advantage of antiplatelet agents and risk factor modification, and a significant risk of complications with endovascular approaches.

SUMMARY

Current evidence argues for aggressive medical management and suggests caution with interventional treatments. We propose that mechanistic information will further refine the risk assessment of patients with IAD to offer targeted therapy.

The evolving paradigm in the management of intracranial atherosclerotic disease

Intracranial atherosclerotic disease (ICAD) is a major cause of ischemic stroke worldwide and represents a significant health problem. The pathogenesis and natural history of ICAD are poorly understood, and rigorous treatment paradigms do not exist as they do for extracranial atherosclerosis. Currently, the best treatment for ICAD remains aspirin therapy, but many patients who are placed on aspirin continue to experience recurrent strokes. As microsurgical and endovascular techniques continue to evolve, the role of extracranial to intracranial bypass operations and stenting are increasingly being reconsidered. We performed a PubMed review of the English literature with a particular focus on treatment options for ICAD and present evidence-based data for the role of surgery and stenting in ICAD against medical therapy alone.

Stenting versus aggressive medical therapy for intracranial arterial stenosis

BACKGROUND

Atherosclerotic intracranial arterial stenosis is an important cause of stroke that is increasingly being treated with percutaneous transluminal angioplasty and stenting (PTAS) to prevent recurrent stroke. However, PTAS has not been compared with medical management in a randomized trial.

METHODS

We randomly assigned patients who had a recent transient ischemic attack or stroke attributed to stenosis of 70 to 99% of the diameter of a major intracranial artery to aggressive medical management alone or aggressive medical management plus PTAS with the use of the Wingspan stent system. The primary end point was stroke or death within 30 days after enrollment or after a revascularization procedure for the qualifying lesion during the follow-up period or stroke in the territory of the qualifying artery beyond 30 days.

RESULTS

Enrollment was stopped after 451 patients underwent randomization, because the 30-day rate of stroke or death was 14.7% in the PTAS group (nonfatal stroke, 12.5%; fatal stroke, 2.2%) and 5.8% in the medical-management group (nonfatal stroke, 5.3%; non-stroke-related death, 0.4%) (P=0.002). Beyond 30 days, stroke in the same territory occurred in 13 patients in each group. Currently, the mean duration of follow-up, which is ongoing, is 11.9 months. The probability of the occurrence of a primary end-point event over time differed significantly between the two treatment groups (P=0.009), with 1-year rates of the primary end point of 20.0% in the PTAS group and 12.2% in the medical-management group.

CONCLUSIONS

In patients with intracranial arterial stenosis, aggressive medical management was superior to PTAS with the use of the Wingspan stent system, both because the risk of early stroke after PTAS was high and because the risk of stroke with aggressive medical therapy alone was lower than expected. (Funded by the National Institute of Neurological Disorders and Stroke and others; SAMMPRIS ClinicalTrials.gov number, NCT00576693.).

PROGRESS: Prevention of Recurrent Stroke

The Perindopril Protection Against Recurrent Stroke Study (PROGRESS) was a randomized placebo-controlled trial which clearly demonstrated that perindopril-based blood pressure (BP)-lowering treatment is one of the most effective and generalizable strategies for secondary prevention of stroke. Beneficial effects of BP lowering were observed on recurrent stroke, other cardiovascular events, disability, dependency, and cognitive function across a variety of subgroups defined by age, sex, geographical region, body mass index, diabetes, atrial fibrillation, chronic kidney disease, and baseline BP levels. Once patients with stroke have stabilized, all patients should receive BP-lowering therapy irrespective of their BP levels. On the basis of recommendations from current international guidelines, BP should be lowered to <140/90 mm Hg in all patients with cerebrovascular disease and to <130/80 mm Hg if therapy is well tolerated.

[Difficult decisions in stroke therapy]

In numerous situations stroke physicians face a lack of evidence during their daily practice. In this report the authors address some of the difficult treatment decisions encountered in acute therapy and secondary prevention. Examples include off-label thrombolysis and prevention in high-risk situations. The available data from trials and registries are discussed, and personal views and recommendations are expressed.

Intracranial atherosclerotic disease

Intracranial atherosclerotic disease (ICAD) is the most common proximate mechanism of ischemic stroke worldwide. Approximately half of those affected are Asians. For diagnosis of ICAD, intra-arterial angiography is the gold standard to identify extent of stenosis. However, noninvasive techniques including transcranial ultrasound and MRA are now emerging as reliable modalities to exclude moderate to severe (50%-99%) stenosis. Little is known about measures for primary prevention of the disease. In terms of secondary prevention of stroke due to intracranial atherosclerotic stenosis, aspirin continues to be the preferred antiplatelet agent although clopidogrel along with aspirin has shown promise in the acute phase. Among Asians, cilostazol has shown a favorable effect on symptomatic stenosis and is of benefit in terms of fewer bleeds. Moreover, aggressive risk factor management alone and in combination with dual antiplatelets been shown to be most effective in this group of patients. Interventional trials on intracranial atherosclerotic stenosis have so far only been carried out among Caucasians and have not yielded consistent results. Since the Asian population is known to be preferentially effected, focused trials need to be performed to establish treatment modalities that are most effective in this population.

Drug eluting stents for symptomatic intracranial and vertebral artery stenosis

The use of bare metal stents (BMS) to prevent recurrent stroke due to stenosis of the cerebral vasculature is associated with high rates of restenosis. Drug-eluting stents (DES) may decrease this risk. We evaluated the performance of DES in a cohort of patients treated at our institution.Consecutive patients treated with DES were identified by a case log and billing records; data regarding procedural details, clinical outcome and angiographic follow-up was obtained by retrospective chart review.Twenty-six patients (27 vessels; 14 vertebral origin (VO); 13 intracranial) were treated. Stenosis was reduced from mean 81% to 8% at the VO and 80% to 2% intracranially. No strokes occurred in the first 24 hours after stenting or at any time point in the VO group during a mean follow-up period of nine months. Among patients with intracranial stents, stroke with permanent disability occurred within 30 days in 1/12 (8%) and after 30 days in 1/11 (9%) with clinical follow-up (mean follow-up, 14 months). Follow-up catheter angiography was obtained in 14/14 (100%) in the VO group at mean eight months and in 8/11 surviving patients (73%) at a mean of ten months after stenting in the intracranial group. The restenosis rate was 21% at the VO (3/14) and 38% (3/8) for intracranial stents. Restenosis at the VO was less frequent than might have been expected from reports utilizing BMS, however, overall restenosis rates appeared higher than previously reported for patients with intracranial DES and comparable with restenosis rates for intracranial BMS.

Collaterals dramatically alter stroke risk in intracranial atherosclerosis

OBJECTIVE

Stroke risk due to intracranial atherosclerosis increases with degree of arterial stenosis. We evaluated the previously unexplored role of collaterals in modifying stroke risk in intracranial atherosclerosis and impact on subsequent stroke characteristics.

METHODS

Collateral flow was graded in blind fashion on 287 of 569 baseline angiograms (stenoses of 50-99% and adequate collateral views) in the Warfarin--Aspirin Symptomatic Intracranial Disease (WASID) trial. Statistical models predicted stroke in the symptomatic arterial territory based on collateral flow grade, percentage of stenosis, and previously demonstrated independent covariates.

RESULTS

Across all stenoses, extent of collaterals was a predictor for subsequent stroke in the symptomatic arterial territory (hazard ratio [HR] none vs good, 1.14; 95% confidence interval [CI], 0.39-3.30; poor vs good, 4.36; 95% CI, 1.46-13.07; p < 0.0001). For 70 to 99% stenoses, more extensive collaterals diminished risk of subsequent territorial stroke (HR none vs good, 4.60; 95% CI, 1.03-20.56; poor vs good, 5.90; 95% CI, 1.25-27.81; p = 0.0427). At milder degrees of stenoses (50-69%), presence of collaterals was associated with greater likelihood of subsequent stroke (HR none vs good, 0.18; 95% CI, 0.04-0.82; poor vs good, 1.78; 95% CI, 0.37-8.57; p < 0.0001). In multivariate analyses, extent of collaterals was an independent predictor for subsequent stroke in the symptomatic arterial territory (HR none vs good, 1.62; 95% CI, 0.52-5.11; poor vs good, 4.78; 95% CI, 1.55-14.7; p = 0.0019).

INTERPRETATION

Collateral circulation is a potent determinant of stroke risk in intracranial atherosclerosis, demonstrating a protective role with severe stenoses and identifying more unstable milder stenoses.

10 questions about intracranial atherosclerotic stenosis

Intracranial atherosclerotic disease is one of the most common causes of stroke worldwide, yet treatment for this disease is still uncertain. This article discusses challenges in the diagnosis and treatment of intracranial stenosis by posing 10 commonly asked questions about this disease.

Intracranial Atherosclerosis

The most relevant ideas discussed in this article are described here. Intracranial atherosclerotic disease (ICAD) represents the most common cause of ischemic stroke worldwide. Its importance in whites may have been underestimated. New technical developments, such as high-resolution MRI, allow direct assessment of the intracranial atherosclerotic plaque, which may have a profound impact on ICAD diagnosis and therapy in the near future. Early detection of ICAD may allow therapeutic intervention while the disease is still asymptomatic. The Barcelonès Nord and Maresme Asymptomatic Intracranial Atherosclerosis Study is presented here. The main prognostic factors that characterize the patients who are at a higher risk for ICAD recurrence are classified and discussed. The best treatment for ICAD remains to be established. The Stenting Versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis Study is currently ongoing to address this crucial issue. These and other topics will be discussed at the Fifth International Intracranial Atherosclerosis Conference (Valladolid, Spain, autumn 2011).

End organ damage in hypertension

BACKGROUND

End organ damage in hypertension can be detected early, reflects accurately the hypertensive patient's overall cardiovascular risk, and should be prevented and treated with antihypertensive treatment.

METHOD

We selectively review the relevant literature since 1995, including the German and European guidelines for the diagnosis and treatment of arterial hypertension.

RESULTS

Measurement of the intima-media thickness in the common carotid artery and of the pulse-wave velocity is now recommended for the early diagnosis of hypertensive vasculopathy. Left ventricular hypertrophy, an important component of hypertensive heart disease, can be diagnosed by echocardiography and with the aid of new electrocardiographic indices. Early signs of hypertensive nephropathy, namely albuminuria and a decreased glomerular filtration rate, are prognostically valuable and easy to detect. Cerebrovascular damage, including early microangiopathic changes, is best diagnosed by magnetic resonance imaging. The treatment of end organ damage due to hypertension centers on blood pressure reduction. Blockade of the renin angiotensin-aldosterone system is an essential part of the treatment of early end organ damage.

CONCLUSION

Hypertensive end organ damage can now be diagnosed early and reversed with specific and aggressive treatment.