Baseline silent cerebral infarction in the Asymptomatic Carotid Atherosclerosis Study

The pathophysiology of patent foramen ovale and its related complications

The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. Importantly, each of these conditions is most commonly observed among specific age groups: migraine in the 20 to 40s, stroke/TIA in the 30-50s and POS in patients >50 years of age. The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. PFO-associated pathologies can therefore be divided into (1) paradoxical systemic embolization and (2) right to left shunting (RLS) of blood through the PFO. Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. Visualization of the flow pattern graphically illustrates the underlying RLS and provides a greater understanding of the critical flow dynamics that determine the frequency, volume, and pathway of flow. In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

Synchronous subarachnoid haemorrhage and ischaemic stroke as a result of complete internal carotid artery occlusion

A previously healthy man in his 60s presents with a one-day history of insidious onset headache and 'walking into doors'. He reported transient right arm pain and tingling but no weakness. A CT brain showed a right middle cerebral artery (MCA) infarct as well as a synchronous right frontal lobe convexal subarachnoid haemorrhage (cSAH). An arch to vertex CT angiogram demonstrated right MCA occlusion and complete right internal carotid artery (ICA) occlusion from its origin. Reconstitution of flow was seen within the distal right ICA at the level of the distal foramen lacerum. A repeat CT of the brain after one week showed a stable appearance of the bleeding and infarct. He was commenced on antiplatelet therapy for the treatment of the ischaemic stroke as well as secondary prevention.This is a rare case of synchronous right MCA infarct as well as a right frontal cSAH secondary to ipsilateral carotid artery occlusion.

Association of Klotho Gene Polymorphism with Cerebral Infarction

Background: We aimed to investigate the expression of Klotho gene in peripheral blood of patients with cerebral infarction (CI) and the association of its polymorphisms with the occurrence of CI. Methods: A total of 60 CI patients (CI group) and 20 healthy people receiving physical examination (control group) were enrolled as the research subjects. The expression of Klotho gene in CI group and control group was determined using enzyme-linked immunosorbent assay kit. Single nucleotide polymorphisms (rs192031, rs200131 and rs102312) in the promoter region of the Klotho gene were typed via conformational difference gel electrophoresis. Besides, whether the distribution frequencies of Klotho genotypes conformed to Hardy-Weinberg equilibrium was evaluated by chi-square test. Meanwhile, the associations of Klotho alleles and gene polymorphisms with CI occurrence were analyzed. Results: The protein expression level of Klotho in the peripheral blood was remarkably lower in patients in CI group than that in control group (P<0.05). Hardy-Weinberg equilibrium analysis revealed that Klotho gene polymorphisms (rs192031, rs200131 and rs102312) conformed to the genetic equilibrium distribution (P>0.05). Gene-based association analysis manifested that only rs192031 polymorphism and alleles were correlated with CI occurrence (P<0.05). Systolic blood pressure and high-density lipoprotein cholesterol were notably higher in CI patients with TT genotype of Klotho gene polymorphism rs192031 than those in control group (P<0.05). Furthermore, there were no associations of rs200131 and rs102312 polymorphisms and alleles with the occurrence of CI (P>0.05). Conclusions: The expression level of Klotho is evidently reduced in the peripheral blood of CI patients. Rs192031 in the promoter region of the Klotho gene is associated with the occurrence of CI, while rs200131 and rs102312 have no relations with CI.

Impact of carotid stenosis on cerebral hemodynamic failure and cognitive impairment progression: a narrative review

Carotid atherosclerosis has a relevant impact on cerebral blood flow regulation. There is accruing evidence that hemodynamic impairment related to the presence of a significant carotid lumen narrowing may predispose to the development of cerebral dysfunctions, including a reduction in cognitive abilities. In the last years an increasing number of findings showed that carotid stenosis did contribute to cognitive impairment not only in relation to the occurrence of cerebral ischemic lesions, but also as an independent risk factor. The principal mechanisms involved are chronic hypoperfusion, microembolization and cerebrovascular reactivity impairment. Moreover, more recent studies showed alterations of regional functional connectivity. In this narrative review, we analyzed the relationships between carotid stenosis, cerebral hemodynamic derangement and cognitive impairment onset and progression, and underlined that cognitive impairment is the final result of the complex interaction between different elements, including also collateral circulation, cerebral hemodynamic status, brain connectivity and pro-inflammatory state. Further, therapeutic approaches, with a specific focus on vascular risk factors correction and on the effectiveness of surgical or endovascular interventions were discussed. We particularly focused our attention on the concept of “asymptomatic carotid stenosis”, and how could a cognitive impairment improve after an intervention, and how this could change the indications to surgical approach. Larger studies and randomized controlled trials are urgently required to better define time, characteristics and effectiveness of both medical and surgical/endovascular approaches.

Revascularization for asymptomatic carotid artery stenosis improves balance and mobility

OBJECTIVE

Balance and mobility function worsen with age, more so for those with underlying chronic diseases. We recently found that asymptomatic carotid artery stenosis (ACAS) restricts blood flow to the brain and might also contribute to balance and mobility impairment. In the present study, we tested the hypothesis that ACAS is a modifiable risk factor for balance and mobility impairment. Our goal was to assess the effect of restoring blood flow to the brain by carotid revascularization on the balance and mobility of patients with high-grade ACAS (≥70% diameter-reducing stenosis).

METHODS

Twenty adults (age, 67.0 ± 9.4 years) undergoing carotid endarterectomy for high-grade stenosis were enrolled. Balance and mobility assessments were performed before and 6 weeks after revascularization. These included the Short Physical Performance Battery, the Berg Balance Scale, the Four Square Step Test, the Dynamic Gait Index (DGI), the Timed Up and Go test, gait speed, the Mini-Balance Evaluation Systems Test (Mini-BESTest), and the Walking While Talking complex test.

RESULTS

Consistent with our previous findings, patients demonstrated reduced scores on the Short Physical Performance Battery, Berg Balance Scale, DGI, and Timed Up and Go test and in gait speed. Depending on the outcome measure, 25% to 90% of the patients had scored in the impaired range at baseline. After surgery, significant improvements were observed in the outcome measures that combined walking with dynamic movements, including the DGI (P = .02) and Mini-BESTest (P = .002). The proportion of patients with Mini-BESTest scores indicating a high fall risk had decreased significantly from 90% (n = 18) at baseline to 40% (n = 8) after surgery (P = .02). We used Pearson's correlations to examine the relationship between balance and mobility before surgery and the change after surgery. Patients with lower baseline DGI and Mini-BESTest scores demonstrated the most improvement after surgery (r = -0.59, P = .006; and r = -0.70, P = .001, respectively).

CONCLUSIONS

Carotid revascularization improved patients' balance and mobility, especially for measures that combine walking and dynamic movements. The greatest improvements were observed for the patients who had been most impaired at baseline.

Editor's Choice - Asymptomatic Carotid Stenosis and Cognitive Impairment: A Systematic Review

OBJECTIVE

The aim was to evaluate the relationship between asymptomatic carotid stenosis (ACS) of any severity and cognitive impairment and to determine whether there is evidence supporting an aetiological role for ACS in the pathophysiology of cognitive impairment.

DATA SOURCES

PubMed/Medline, Embase, Scopus, and the Cochrane library.

REVIEW METHODS

This was a systematic review (35 cross sectional or longitudinal studies) RESULTS: Study heterogeneity confounded data interpretation, largely because of no standardisation regarding cognitive testing. In the 30 cross sectional and six longitudinal studies (one included both), 33/35 (94%) reported an association between any degree of ACS and one or more tests of impaired cognitive function (20 reported one to three tests with poorer cognition; 11 reported four to six tests with poorer cognition, while three studies reported seven or more tests with poorer cognition). There was no evidence that ACS caused cognitive impairment via silent cortical infarction, or via involvement in the pathophysiology of lacunar infarction or white matter hyperintensities. However, nine of 10 studies evaluating cerebral vascular reserve (CVR) reported that ACS patients with impaired CVR were significantly more likely to have cognitive impairment and that impaired CVR was associated with worsening cognition over time. Patients with severe ACS but normal CVR had cognitive scores similar to controls.

CONCLUSION

Notwithstanding significant heterogeneity within the constituent studies, which compromised overall interpretation, 94% of studies reported an association between ACS and one or more tests of cognitive impairment. However, "significant association" does not automatically imply an aetiological relationship. At present, there is no clear evidence that ACS causes cognitive impairment via silent cortical infarction (but very few studies have addressed this question) and no evidence of ACS involvement in the pathophysiology of white matter hyperintensities or lacunar infarction. There is, however, better evidence that patients with severe ACS and impaired CVR are more likely to have cognitive impairment and to suffer further cognitive decline with time.

Study of Symptomatic vs. Silent Brain Infarctions on MRI in Elderly Subjects

Brain infarctions are closely associated with future risk of stroke and dementia. Our goal was to report (i) frequency and characteristics that differentiate symptomatic vs. silent brain infarctions (SBI) on MRI and (ii) frequency and location by vascular distribution (location of stroke by major vascular territories) in a population based sample. From Mayo Clinic Study of Aging, 347 participants (≥50 years) with infarcts detected on their first MRI were included. Infarct information was identified visually on a FLAIR MRI image and a vascular territory atlas was registered to the FLAIR image data in order to identify the arterial territory of infarction. We identified the subset with a clinical history of stroke based on medical chart review and used a logistic regression to evaluate the risk factors associated with greater probability of a symptomatic stroke vs. SBI. We found that 14% of all individuals with infarctions had a history of symptomatic stroke (Silent: n = 300, symptomatic: n = 47). Factors associated with a symptomatic vs. SBI were size which had an odds ratio of 3.07 (p < 0.001), greater frequency of hypertension (odds ratio of 4.12, p = 0.025) and alcohol history (odds ratio of 4.58, p = 0.012). The frequency of infarcts was greater in right hemisphere compared to the left for SBI. This was primarily driven by middle cerebral artery (MCA) infarcts (right = 60%, left = 40%, p = 0.005). While left hemisphere strokes are more common for symptomatic carotid disease and in clinical trials, right hemispheric infarcts may be more frequent in the SBI group.

Asymptomatic carotid stenosis is associated with mobility and cognitive dysfunction and heightens falls in older adults

BACKGROUND

Atherosclerosis of the carotid bifurcation with plaque formation causes asymptomatic carotid artery stenosis (ACAS), which may also be associated with cerebral hypoperfusion. Cerebral hypoperfusion adversely affects multiple aspects of mobility and cognition. This study tests the hypothesis that community-dwelling older adults with a 50% or greater diameter-reducing ACAS will have mobility and cognitive impairments that heighten their risk for falls.

METHODS

Eighty community-dwelling adults completed a mobility assessment (Short Physical Performance Battery, Berg Balance Scale, Four Square Step Test, Dynamic Gait Index, Timed Up and Go, and gait speed), self-reported physical function (Activities-Specific Balance Confidence, SF-12 Physical Function Component), and cognitive tests (Mini-Mental State Examination). Falls were recorded for the past 6 months. Standardized carotid ultrasound examination classified participants into no stenosis (<50% diameter reduction) (n = 54), moderate stenosis (50%-69%) (n = 17), and high-grade stenosis (70%-99%) (n = 9) groups. Linear and logistic regression analyses determined the associations between these measures and the degree of stenosis (three groups).

RESULTS

Logistic regression analysis showed their degree of stenosis was associated with reductions in mobility (Short Physical Performance Battery [P = .008], Berg Balance Scale [P = .0008], Four Square Step Test [P = .005], DGI [P = .0001], TUG [P = .0004], gait speed [P = .02]), perceived physical function (ABC [P < .0001], SF-12 Physical Function Component [P < .0001]), and cognition (MMSE [P = .003]). Adults with moderate- and high-grade stenosis had a greater incidence of falls compared with those without stenosis (relative risk, 2.86; P = .01). Results remained unchanged after adjustment for age, sex and cardiovascular risk factors.

CONCLUSIONS

ACAS is associated with impaired mobility and cognition that are accompanied with increased fall risk. These impairments increased with worsening severity.

Stroke Laterality Did Not Modify Outcomes in the HERMES Meta-Analysis of Individual Patient Data of 7 Trials

Background and Purpose—

There is contradictory evidence on the impact of the stroke side (hemisphere) on outcomes. We investigated any effect modification by laterality on stroke patients’ outcomes in recent endovascular trials.

Methods—

Individual patient-level data were combined in this meta-analysis of all patients included in randomized trials comparing endovascular thrombectomy predominantly done with stent retrievers with standard care in anterior circulation ischemic patients with stroke (HERMES [Highly Effective Reperfusion Using Multiple Endovascular Devices] Collaboration). We stratified the 90-day functional outcome assessed by ordinal analysis of the modified Rankin Scale according to the stroke side of patients treated with endovascular therapy versus standard care, adjusted for important prognostic variables.

Results—

The meta-analysis included 1737 patients (871 right hemispheric strokes and 866 left hemispheric) from 7 trials. Baseline median National Institutes of Health Stroke Scale scores were significantly higher in left (20) versus right (16) hemispheric strokes ( P <0.001). Other clinical and radiological baseline characteristics were similar. The beneficial response to endovascular therapy assessed by 90-day modified Rankin Scale shift was not modified by the side of the stroke. There were no significant differences between right and left hemispheric stroke in the 90-day functional outcome (modified Rankin Scale score ≤2; 40.7% [95% CI, 37.4%–44.1%] versus 37.6% [95% CI, 37.4%–44.1%]; P =0.19), median final infarct volumes (45 versus 39.5 mL, P =0.51), nor 90-day mortality (15.1% vs 16.8%, P =0.31).

Conclusions—

Stroke side was not a prognostic factor and did not modify the treatment effect among patients treated in the endovascular or control groups in recent endovascular thrombectomy trials.

Subclinical Cerebrovascular Disease: Epidemiology and Treatment

PURPOSE OF REVIEW

Subclinical cerebrovascular disease (sCVD) is highly prevalent in older adults. The main neuroimaging findings of sCVD include white matter hyperintensities and silent brain infarcts on T2-weighted MRI and cerebral microbleeds on gradient echo or susceptibility-weighted MRI. In this paper, we will review the epidemiology of sCVD, the current evidence for best medical management, and future directions for sCVD research.

RECENT FINDINGS

Numerous epidemiologic studies show that sCVD, in particular WMH, is an important risk factor for the development of dementia, stroke, worse outcomes after stroke, gait instability, late-life depression, and death. Effective treatment of sCVD could have major consequences for the brain health of a substantial portion of older Americans. Despite the link between sCVD and many vascular risk factors, such as hypertension or hyperlipidemia, the optimal medical treatment of sCVD remains uncertain. Given the clinical equipoise about the risk versus benefit of aggressive medical management for sCVD, clinical trials to examine pragmatic, evidence-based approaches to management of sCVD are needed. Such a trial could provide much needed guidance on how to manage a common clinical scenario facing internists and neurologists in practice.

The Association between Carotid Artery Atherosclerosis and Silent Brain Infarction: A Systematic Review and Meta-analysis

BACKGROUND

Carotid atherosclerosis is responsible for ~20% of ischemic strokes, but it is unclear whether carotid disease is associated with the presence of downstream silent brain infarction (SBI). We performed a systematic review and meta-analysis to study the relationship between SBI and 2 separate manifestations of carotid atherosclerosis, carotid intima-media thickening (IMT) and luminal stenosis.

METHODS

Ovid MEDLINE, Ovid Embase, and the Cochrane Library Database were searched with an additional search of references and citing articles of target studies. Articles were included if they reported an association between carotid IMT or stenosis and magnetic resonance imaging-defined SBI, excluding SBIs found after carotid intervention.

RESULTS

We pooled 7 studies of carotid IMT reporting on 1469 subjects with SBI and 5102 subjects without SBI. Subjects with SBI had a larger mean IMT than subjects without SBI (pooled standardized mean difference, .37; 95% confidence interval [CI], .23-.51; P < .0001). We pooled 11 studies of carotid stenosis reporting on 12,347 subjects (2110 subjects with carotid stenosis and 10,237 subjects without carotid stenosis). We found a higher prevalence of SBI among subjects with carotid stenosis (30.4% versus 17.4%). Our pooled random-effects analysis showed a significant positive relationship between carotid stenosis and SBI (odds ratio, 2.78; 95% CI, 2.19-3.52; P < .0001).

CONCLUSIONS

Two forms of atherosclerotic disease, carotid IMT and stenosis, are both significantly associated with SBI. This review highlights a lack of consistent definitions for carotid disease measures and little evidence evaluating SBI prevalence downstream from carotid stenosis.

Evaluation by Magnetic Resonance Imaging of Silent Brain Infarcts in Preoperative and Postoperative Asymptomatic Carotid Surgery

BACKGROUND

To report the prevalence of silent brain infarcts (SBI) at magnetic resonance imaging (MRI) before and after surgery for asymptomatic high grade carotid stenosis.

METHODS

This is a single center retrospective observational study. Asymptomatic patients who underwent carotid endarterectomy between October 2012 and October 2014 were included. The preoperative assessment included a Doppler and a computed tomographic (CT) scan dating less than 3 months. A neurological examination was performed during the anesthesia consultation and in the 15 days before surgery. An MRI angiography was performed the day before and 3 days after surgery and was analyzed by an independent neuroradiologist. Preoperative analysis focused on the presence of ischemic events at MRI. The type of plaque, the supra aortic trunk lesions, and the quality of the circle of Willis were analyzed using Doppler and CT scanning. Postoperatively, we searched for signs of postoperative ischemic events at MRI.

RESULTS

Forty-one patients were included (85.4% of men), and the mean age was 72.4 ± 8.3 years. We noted 7 (17.1%) contralateral stenoses (>50%) and 2 (4.9%) contralateral thromboses, 6 (14.6%) vertebral stenoses, and 7 (17.1%) abnormalities of the circle of Willis. The morphological analysis described 6 unstable plaques including 4 ulcerated, 1 pseudodissection, and 1 intraplaque hemorrhage. Preoperatively, we noted the presence of 21 (51.2%) ischemic lesions including 9 (21.9%) multiple lacunar ischemic events and 12 (29.3%) silent arterial territory infarcts. Eversion was performed for all patients except for 6 (14.6%), for whom a bypass was necessary. No deaths or major complications were observed in the 30 postoperative days. Postoperatively, MRI showed 3 (7.3%) asymptomatic recent ischemic strokes, 1 ipsilateral middle cerebral artery (MCA) stroke, and 2 contralateral (cerebellar and MCA) strokes.

CONCLUSIONS

Patients with asymptomatic significant carotid stenosis show many preoperative SBI indicating a significant embolic risk. It is difficult to conclude about intraoperative embolic risk, but we hope that more data could demonstrate the importance of MRI for the preoperative evaluation of carotid plaques and brain parenchyma, to identify high-risk embolic patients.

Ten-year risk of stroke in patients with previous cerebral infarction and the impact of carotid surgery in the Asymptomatic Carotid Surgery Trial

BACKGROUND

Silent brain infarcts are common in patients at increased risk of stroke and are associated with a poor prognosis. In patients with asymptomatic carotid stenosis, similar adverse associations were claimed, but the impact of previous infarction or symptoms on the beneficial effects of carotid endarterectomy is not clear. Our aim was to evaluate the impact of prior cerebral infarction in patients enrolled in the Asymptomatic Carotid Surgery Trial, a large trial with 10-year follow-up in which participants whose carotid stenosis had not caused symptoms for at least six months were randomly allocated either immediate or deferred carotid endarterectomy.

METHODS

The first Asymptomatic Carotid Surgery Trial included 3120 patients. Of these, 2333 patients with baseline brain imaging were identified and divided into two groups irrespective of treatment assignment, 1331 with evidence of previous cerebral infarction, defined as a history of ischemic stroke or transient ischemic attack > 6 months prior to randomization or radiological evidence of an asymptomatic infarct (group 1) and 1002 with normal imaging and no prior stroke or transient ischemic attack (group 2). Stroke and vascular deaths were compared during follow-up, and the impact of carotid endarterectomy was observed in both groups.

RESULTS

Baseline characteristics of patients with and without baseline brain imaging were broadly similar. Of those included in the present report, male gender and hypertension were more common in group 1, while mean ipsilateral stenosis was slightly greater in group 2. At 10 years follow-up, stroke was more common among participants with cerebral infarction before randomization (absolute risk increase 5.8% (1.8-9.8), p = 0.004), and the risk of stroke and vascular death was also higher in this group (absolute risk increase 6.9% (1.9-12.0), p = 0.007). On multivariate analysis, prior cerebral infarction was associated with a greater risk of stroke (hazard ratio = 1.51, 95% confidence interval: 1.17-1.95, p = 0.002) and of stroke or other vascular death (hazard ratio = 1.30, 95% confidence interval: 1.11-1.52, p = 0.001). At 10 years, greater absolute benefits from immediate carotid endarterectomy were seen in those patients with prior cerebral infarction (6.7% strokes immediate carotid endarterectomy vs. 14.7% delayed carotid endarterectomy; hazard ratio 0.47 (0.34-0.65), p = 0.003), compared to those lower risk patients without prior cerebral infarction (6.0% vs. 9.9%, respectively; hazard ratio 0.61 (0.39-0.94), p = 0.005), though it must be emphasized that the first Asymptomatic Carotid Surgery Trial was not designed to test this retrospective and non-randomized comparison.

CONCLUSIONS

Asymptomatic carotid stenosis patients with prior cerebral infarction have a higher stroke risk during long-term follow-up than those without prior cerebral infarction. Evidence of prior ischemic events might help identify patients in whom carotid intervention is particularly beneficial.

The Mechanism of and Preventive Therapy for Stroke in Patients with Atrial Fibrillation

Atrial fibrillation is a major cardiac cause of stroke, and a pathogenesis involving thrombus formation in patients with atrial fibrillation is well established. A strategy for rhythm control that involves catheter ablation and anticoagulation therapy is evolving. A strategy for rhythm control that restores and maintains sinus rhythm should reduce the risk of ischemic stroke that is associated with atrial fibrillation; however, this is yet to be proven in large-scale randomized controlled trials. This paper reviews the emerging role of rhythm control therapy for atrial fibrillation to prevent stroke.

Silent Brain Infarction and Risk of Future Stroke: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Silent brain infarction (SBI) on magnetic resonance imaging has been proposed as a subclinical risk marker for future symptomatic stroke. We performed a systematic review and meta-analysis to summarize the association between magnetic resonance imaging-defined SBI and future stroke risk.

METHODS

We searched the medical literature to identify cohort studies involving adults with SBI detected by magnetic resonance imaging who were subsequently followed up for incident clinically defined stroke. Study data and quality assessment were recorded in duplicate with disagreements in data extraction resolved by a third reader. Strength association between magnetic resonance imaging-detected SBI and future symptomatic stroke was measured by an hazard ratio.

RESULTS

The meta-analysis included 13 studies (14 764 subjects) with a mean follow-up ranging from 25.7 to 174 months. SBI predicted the occurrence of stroke with a random effects crude relative risk of 2.94 (95% confidence interval, 2.24-3.86, P<0.001; Q=39.65, P<0.001). In the 8 studies of 10 427 subjects providing hazard ratio adjusted for cardiovascular risk factors, SBI was an independent predictor of incident stroke (hazard ratio, 2.08 [95% confidence interval, 1.69-2.56; P<0.001]; Q=8.99; P=0.25). In a subgroup analysis pooling 9483 stroke-free individuals from large population-based studies, SBI was present in ≈18% of participants and remained a strong predictor of future stroke (hazard ratio, 2.06 [95% confidence interval, 1.64-2.59]; P<0.01).

CONCLUSIONS

SBI is present in ≈1 in 5 stroke-free older adults and is associated with a 2-fold increased risk of future stroke. Future studies of in-depth stroke risk evaluations and intensive prevention measures are warranted in patients with clinically unrecognized radiologically evident brain infarctions.

CNS involvement in V30M transthyretin amyloidosis: clinical, neuropathological and biochemical findings

OBJECTIVES

Since liver transplant (LT) was introduced to treat patients with familial amyloid polyneuropathy carrying the V30M mutation (ATTR-V30M), ocular and cardiac complications have developed. Long-term central nervous system (CNS) involvement was not investigated. Our goals were to: (1) identify and characterise focal neurological episodes (FNEs) due to CNS dysfunction in ATTR-V30M patients; (2) characterise neuropathological features and temporal profile of CNS transthyretin amyloidosis.

METHODS

We monitored the presence and type of FNEs in 87 consecutive ATTR-V30M and 35 non-ATTR LT patients. FNEs were investigated with CT scan, EEG and extensive neurovascular workup. MRI studies were not performed because all patients had cardiac pacemakers as part of the LT protocol. We characterised transthyretin amyloid deposition in the brains of seven ATTR-V30M patients, dead 3-13 years after polyneuropathy onset.

RESULTS

FNEs occurred in 31% (27/87) of ATTR-V30M and in 5.7% (2/35) of the non-ATTR transplanted patients (OR=7.0, 95% CI 1.5 to 33.5). FNEs occurred on average 14.6 years after disease onset (95% CI 13.3 to 16.0) in ATTR-V30M patients, which is beyond the life expectancy of non-transplanted ATTR-V30M patients (10.9, 95% CI 10.5 to 11.3). ATTR-V30M patients with FNEs had longer disease duration (OR=1.24; 95% CI 1.07 to 1.43), renal dysfunction (OR=4.65; 95% CI 1.20 to 18.05) and were men (OR=3.57; 95% CI 1.02 to 12.30). CNS transthyretin amyloidosis was already present 3 years after polyneuropathy onset and progressed from the meninges and its vessels towards meningocortical vessels and the superficial brain parenchyma, as disease duration increased.

CONCLUSIONS

Our findings indicate that CNS clinical involvement occurs in ATTR-V30M patients regardless of LT. Longer disease duration after LT can provide the necessary time for transthyretin amyloidosis to progress until it becomes clinically relevant. Highly sensitive imaging methods are needed to identify and monitor brain ATTR. Disease modifying therapies should consider brain TTR as a target.

The impact of carotid artery stenting on cognitive function in patients with extracranial carotid artery stenosis

BACKGROUND

The effect of carotid artery stenting (CAS) on cognitive function in patients with extracranial carotid artery stenosis is equivocal. The aim of this study was to examine the impact of CAS on various domains of cognitive function.

METHODS

We performed a meta-analysis of the studies evaluating various domains of cognitive function before and after CAS, namely, (1) global cognition using Mini-Mental State Examination (MMSE) and Rey Auditory Verbal Learning Test (RAVLT), (2) executive function using Trail Making Test (TMT) A or Color Trails Test (CTT) A and TMT B or CTT B, (3) language ability using Boston Naming Test (BNT), (4) memory, (5) attention/psychomotor speed, and (6) functional ability, using various cognitive tests. Pooled weighted mean differences (WMDs) and standardized mean differences (SMDs) with 95% confidence intervals (95% CIs) were appropriately calculated using fixed or random effects models after assessing between-study heterogeneity. Meta-regression analysis was performed with number of patients per study; mean age (years); follow-up (months); proportion of men; proportion of patients with hypertension, diabetes mellitus, hyperlipidemia, smoking, and coronary artery disease; proportion of symptomatic patients; and degree of ipsilateral and degree of contralateral carotid stenosis as covariates.

RESULTS

Sixteen studies were eligible, including a total of 626 CAS patients. A statistically significant improvement of global cognition was detected with MMSE (WMD = 0.67, 95% CI = 0.29-1.05, P < 0.001; follow-up = 5.6 months), but not with RAVLT (SMD = 0.45, 95% CI = -0.03 to 0.93, P = 0.07; follow-up = 2.4 months). Significant improvement of memory (SMD = 0.33, 95% CI = 0.11-0.55, P < 0.01; follow-up = 4.1 months) and attention/psychomotor speed (SMD = 0.21, 95% CI = 0.04-0.39, P = 0.02; follow-up = 4 months) was also detected. No statistically significant effect on executive function (TMT A/CTT A and TMT B/CTT B; SMD = 0.08, 95% CI = -0.10 to 0.26, P = 0.39; follow-up = 3.9 months and SMD = -0.02, 95% CI = -0.20 to 0.16, P = 0.82, respectively; follow-up = 3.9 months), language ability (BNT; SMD = 0.24, 95% CI = -0.05 to 0.54, P = 0.10; follow-up = 4 months), and functional ability (SMD = -0.05, 95% CI = -0.25 to 0.15, P = 0.63; follow-up = 3.8 months) was observed. No significant effects of the examined covariates were demonstrated in the meta-regression analyses.

CONCLUSIONS

CAS may be associated with improvement in global cognition, memory, and attention/psychomotor speed. There was no positive effect on executive function, language, and functional ability, but CAS was not associated with a decline in any area of cognitive function. Future studies in larger groups of patients are probably needed to fully investigate the long-term effect of CAS on cognition in patients with carotid artery stenosis.

Middle cerebral artery pulsatility index and cognitive improvement after carotid endarterectomy for symptomatic stenosis

OBJECT

Transcranial Doppler (TCD) is frequently used to evaluate peripheral cerebral resistance and cerebral blood flow (CBF) in the middle cerebral artery prior to and during carotid endarterectomy (CEA). Patients with symptomatic carotid artery stenosis may have reduced peripheral cerebral resistance to compensate for inadequate CBF. The authors aim to determine whether symptomatic patients with reduced peripheral cerebral resistance prior to CEA demonstrate increased CBF and cognitive improvement as early as 1 day after CEA.

METHODS

Fifty-three patients with symptomatic CEA were included in this observational study. All patients underwent neuropsychometric evaluation 24 hours or less preoperatively and 1 day postoperatively. The MCA was evaluated using TCD for CBF mean velocity (MV) and pulsatility index (PI). Pulsatility index ≤ 0.80 was used as a cutoff for reduced peripheral cerebral resistance.

RESULTS

Significantly more patients with baseline PI ≤ 0.80 exhibited cognitive improvement 1 day after CEA than those with PI > 0.80 (35.0% vs 6.1%, p = 0.007). Patients with cognitive improvement had a significantly greater increase in CBF MV than patients without cognitive improvement (13.4 ± 17.1 cm/sec vs 4.3 ± 9.9 cm/sec, p = 0.03). In multivariate regression model, a baseline PI ≤ 0.80 was significantly associated with increased odds of cognitive improvement (OR 7.32 [1.40-59.49], p = 0.02).

CONCLUSIONS

Symptomatic CEA patients with reduced peripheral cerebral resistance, measured as PI ≤ 0.80, are likely to have increased CBF and improved cognitive performance as early as 1 day after CEA for symptomatic carotid artery stenosis. Revascularization in this cohort may afford benefits beyond prevention of future stroke. Clinical trial registration no: NCT00597883 ( ClinicalTrials.gov ).

Subdural hematomas: an analysis of 1181 Kashmiri patients

BACKGROUND

We endeavored to analyze patients of subacute and chronic subdural hematomas studied in a 4-year period at the Sher-i-Kashmir Institute of Medical Sciences, Kashmir, India.

METHODS

The study was a retrospective analysis of 1181 patients of subdural hematomas. Demographic characteristics, clinico-radiologic features, operative modalities, and outcome were studied. Acute subdural hematomas were excluded from the study.

RESULTS

The mean age was 60.4 ± 12.4 and males outnumbered females. Chronic subdural collections were more common than subacute subdural hematomas and left side predominated. Two burr holes with closed-system drainage was used in most patients. Incidence of postoperative seizures is very low. Overall recurrence rates were low; however, multilocular hematomas had the highest incidence of recurrence. Morbidity and mortality were 7.53% and 2.96%, respectively. Preoperative neurologic grade correlated with outcome.

CONCLUSIONS

Subdural hematomas are common in elderly males. Preoperative neurologic grade dictates the outcome. Multilocular hematomas have a higher chance of recurrence. Craniotomy should be reserved for recurrent hematomas, and there may be a scope of craniotomy for multilocular chronic subdural hematomas at the outset. Antiepileptic prophylaxis is not routinely recommended.

Basal Cerebral Computed Tomography as Diagnostic Tool to Improve Patient Selection in Asymptomatic Carotid Artery Stenosis

One-hundred patients were included to evaluate the role of cerebral computed tomography (CT) to improve patient selection in asymptomatic internal carotid stenosis. Symptomatic patients were assigned to group A, asymptomatic patients to group B. A cerebral CT pattern A was observed in groups A and B in 60% and 20%, respectively ( P < .0001). Between A and B groups, type 6 plaques were found, respectively, in 26.7% and 7.5% of patients ( P = .01); a type 5 in 51.7% and 45% ( P = .32) of patients; and a type 4 in 21.7% and 47.5% of patients, respectively ( P = .006). Within B group, the association of CT pattern A and histological plaque level 4, 5, and 6 was, respectively, 25% ( P = .15), 50% ( P = .53), and 25% ( P = .16). In group B, a 7-fold risk increase in CT pattern A was found in patients with level 6 plaque. In asymptomatic patients with high-risk plaque, a basal cerebral CT scan can be used as diagnostic tool to improve patient selection for intervention.

Silent cerebral events in asymptomatic carotid stenosis

BACKGROUND

Approximately 20% of strokes are attributable to carotid stenosis. However, the number of asymptomatic patients needed to prevent one stroke or death with endarterectomy is high at 17 to 32. There is a clear need to identify asymptomatic individuals at high risk of developing future ischemic events to improve the cost-effectiveness of surgery. Our aim was to examine the evidence for subclinical microembolization and silent brain infarction in the prediction of stroke in asymptomatic carotid stenosis using transcranial Doppler (TCD), computed tomography (CT), and magnetic resonance imaging (MRI).

METHODS

The review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Articles regarding humans between 1966 and 2010 were identified through systematic searches of Pubmed, MEDLINE, and EMBASE electronic databases using a predetermined search algorithm.

RESULTS

Fifty-eight full text articles met the inclusion criteria. A median of 28% of microemboli positive patients experienced a stroke or transient ischemic attack during follow-up compared with 2% of microemboli negative patients (P = .001). The same was true for the end point of stroke alone with a median of 10% of microemboli positive patients experiencing a stroke vs 1% of microemboli negative patients (P = .004). A specific pattern of silent CT infarctions was related to future stroke risk (odds ratio [OR] = 4.6; confidence interval [CI] = 3.0-7.2; P < .0001). There are no prospective MRI studies linking silent infarction and stroke risk.

CONCLUSIONS

There is level 1 evidence for the use of TCD to detect microembolization as a risk stratification tool. However, this technique requires further investigation as a stroke prevention tool and would be complemented by improvements in carotid plaque imaging.

MRI of carotid atherosclerosis: clinical implications and future directions

Atherosclerosis is now widely recognized as a multifactorial disease with outcomes that arise from complex factors such as plaque components, blood flow, and inflammation. Despite recent advances in understanding of plaque biology, diagnosis, and treatment, atherosclerosis remains a leading cause of morbidity and mortality. Further research into the development and validation of reliable indicators of the high-risk individual is greatly needed. Carotid MRI is a histologically validated, noninvasive imaging method that can track disease progression and regression, and quantitatively evaluate a spectrum of parameters associated with in vivo plaque morphology and composition. Intraplaque hemorrhage and the lipid-rich necrotic core are the best indicators of lesion severity currently visualized by carotid MRI. However, MRI methods capable of imaging other important aspects of carotid atherosclerotic disease in vivo-including inflammation, neovascularization, and mechanical forces-are emerging and may aid in advancing our understanding of the pathophysiology of this multifactorial disease.

Chronic subdural haematomas are more common on the left than on the right

Subdural haematomas (SDHs), and in particular chronic subdural haematomas (CSDHs), are commonly encountered in a neurosurgical practice. The aetiology, presentation, management and prognosis of these are well documented but there are few publications that report on their side prevalence (laterality). We report an analysis of all patients (both operated on and conservatively managed) who presented to the Neurosurgical Service at Christchurch Hospital with SDHs between 1 January 1996 and 30 June 2006. A total of 413 patients presented with a total of 450 SDHs, of which 150 (33.3%) were acute, 38 were (8.4%) subacute and 262 (58.2%) were chronic. The patients ranged in age from 3 months to 95 years. The mean (+/-standard deviation, SD) age of patients with acute SDH was 50.9+/-25.8 years, 65.4+/-19.8 years for subacute SDH and 68.9+/-19.7 years for chronic SDH. A total of 275 (67%) patients were male and 138 (33%) female, with the male predominance occurring in all subgroups. The SDHs were distributed unilaterally in the acute and subacute groups; however, CSDHs occurred more frequently on the left side (57.2% compared to 42.7% on the right; p=0.0345). We discuss the likely reasons behind the increased rate of CSDHs diagnoses on the left side.

Prevalence and correlates of silent cerebral infarcts in the Framingham offspring study

BACKGROUND AND PURPOSE

Previous estimates of the prevalence of silent cerebral infarction (SCI) on MRI in community-based samples have varied between 5.8% and 17.7% depending on age, ethnicity, presence of comorbidities, and imaging techniques. We document the prevalence and risk factors associated with SCI at midlife in the community-based Framingham sample.

METHODS

Our study sample comprised 2040 Framingham Offspring (53% female; mean age, 62+/-9 years) who attended the sixth examination (1996-1998), underwent volumetric brain MRI (1999-2005,) and were free of clinical stroke at MRI. We examined the age- and sex-specific prevalences and the clinical correlates of SCI using multivariable logistic regression models.

RESULTS

At least 1 SCI was present in 10.7% of participants; 84% had a single lesion. SCI was largely located in the basal ganglia (52%), other subcortical (35%) areas, and cortical areas (11%). Prevalent SCI was associated with the Framingham Stroke Risk Profile score (OR, 1.27; 95% CI, 1.10-1.46); stage I hypertension was determined by JNC-7 criteria (OR,1.56; CI,1.15-2.11), an elevated plasma homocysteine in the highest quartile (OR, 2.23; CI, 1.42-3.51), atrial fibrillation (OR, 2.16; CI, 1.07-4.40), carotid stenosis >25% (OR, 1.62; 1.13-2.34), and increased carotid intimal-medial thickness above the lowest quintile (OR, 1.65; CI, 1.22-2.24).

CONCLUSIONS

The prevalence and distribution of SCI in the Framingham Offspring are comparable to previous estimates. Risk factors previously associated with clinical stroke were also found to be associated with midlife SCI. Our results support current guidelines emphasizing early detection and treatment of stroke risk factors.

[A case of nonarteritic anterior ischemic optic neuropathy with hypertension, diabetes mellitus, hyperlipidemia and severe stenosis of the internal carotid artery]

A 76 year-old man had had hypertension, diabetes mellitus and hyperlipidemia since 1985, and bruit in his left neck since 1993. He had abrupt decrease in left visual acuity on November 24, 2005, and visited an ophthalmologist. On November 28, his corrected visual acuity was 1.0 in the right and 0.1 in the left. The examination of optic fundi showed ear-side edema of the left optic disk. Fluorescence examination of the left optic fundus showed delay in early filling and later hyperfluorescence. Goldman visual field examination showed horizontal lower semiblindness. Since he did not complain of eye pain, his blood examination showed no reaction of inflammation, and he had hypertension, diabetes mellitus and hyperlipidemia, anterior ischemic optic neuropathy was diagnosed. The treatment with aspirin, alprostadil and prednisolone transiently improved the optic fundi and visual acuity, but his left visual acuity returned to 0.1. Carotid ultrasonography showed 95 percent stenosis in the left internal carotid artery. As there is no established treatment for ischemic optic neuropathy, the management of risk factors is most important.

Chronic ischemia and neurocognition

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

Metallothionein expression in the high-risk carotid atherosclerotic plaque

OBJECTIVE

Metallothioneins (MTs) are antioxidant proteins expressed in response to injury. We evaluated MT immunoreactivity in carotid plaques obtained from asymptomatic and symptomatic patients. We also assessed the relationship between ultrasonic plaque echodensity, histological grading, computed tomography findings and MT expression.

METHODS AND RESULTS

In this ongoing prospective study, patients (n = 123, mean age (+/-SD) 68.4 +/- 7.7 years, 97 men) with high-grade carotid stenosis underwent carotid endarterectomy. Specimens were assessed histologically and immunohistochemically. Echolucent plaques (types 1+2) were more common in symptomatic patients (p < 0.0001) and had more advanced histological lesions (p < 0.0001). Echolucent plaques expressed MTs (in macrophages, fibroblasts and T-lymphocytes) significantly more than echogenic plaques (types 3+4) (all p < 0.0001). MT expression was mainly related to carotid plaque echolucency rather than the presence of symptoms. MT expression was significantly more common in advanced histological lesions. Plaques from asymptomatic or symptomatic patients with abnormal computed tomography findings also showed increased MT expression. There was a time-dependent fall in MT expression after cerebrovascular events (p < or = 0.011).

CONCLUSIONS

MT overexpression may be triggered in unstable plaques as a local protective factor. There is a need to identify both causative and protective predictors of the 'vulnerable plaque' in the 'vulnerable patient'. Further studies are needed to resolve these issues.

High Incidence of Infarction in the Left Cerebral Hemisphere Among Young Adults

We hypothesized that left cerebral hemisphere infarction is more frequent than right hemisphere infarction among young adults. Furthermore, we aimed to evaluate possible causes for this asymmetry. Cases were found by computer search from hospital registries at each of the 5 acute-care hospitals in a well-defined population in Hordaland County, western Norway. Important parameters used in the analysis were derived from the patient records. A total of 98 patients had left hemisphere infarctions, and 70 patients had right hemisphere infarctions (P = .037). This difference was due mostly to the higher incidence of infarction in the left middle cerebral artery (MCA) territory compared with the right MCA territory among the male subjects (P = .016). Lacunar infarction was equally distributed, whereas nonlacunar infarction was more frequent in the left MCA territory among the men (P = .016). A high frequency of left MCA infarctions may be associated with more frequent atherosclerosis in the left carotid artery, lateralization of cortical functions, or both in young adults.

Asymptomatic Carotid Artery Stenosis: Past, Present and Future

BACKGROUND

The role of carotid endarterectomy (CEA) for asymptomatic carotid artery stenosis (aCAS) remains a matter of debate. It seems that not only the degree of stenosis, but also other factors have to be taken in account to improve patient selection and increase the benefit of CEA for aCAS.

METHODS AND RESULTS

The literature pertaining aCAS was reviewed in order to describe the natural history, risk of stroke and benefit of CEA for patients with aCAS in regard to several factors.

CONCLUSION

The benefit of CEA for aCAS is low. Current factors influencing the indication for CEA are severity of stenosis, age, contralateral disease, stenosis progression to >80%, gender, concomitant operations and life expectancy. To improve patient selection investigations will concentrate on plaque characteristics and instability and cerebral hemodynamics and metabolism.

Stroke Risk of Asymptomatic Intra- and Extracranial Large-Artery Disease in Apparently Healthy Adults

BACKGROUND

The predictive value of asymptomatic intracranial artery stenosis for future stroke remains uncertain. The aim of this study is to assess the stroke risk of asymptomatic intracranial artery stenosis and to compare it with that of extracranial artery disease.

METHODS

The study subjects were 2,924 participants (mean age 55 years) without any history of stroke. We examined the relation between intra- or extracranial large-artery disease and subsequent cerebrovascular events (mean follow-up 63 months).

RESULTS

The incidence rate of total cerebrovascular events in persons with intracranial artery stenosis was 1.3% per year. In the group without plaque in the extracranial carotid arteries, the annual rate of total cerebrovascular events was only 0.6%, but in the group with plaque, the rate was 3.6%. Kaplan-Meier analysis of total events showed a significant difference between the 2 groups (p = 0.002).

CONCLUSIONS

The stroke risk in subjects with asymptomatic extracranial artery disease is markedly increased if intracranial artery stenosis is also present.

Cerebral hemodynamics in symptomatic and asymptomatic patients with severe unilateral carotid stenosis before and after carotid endarterectomy

BACKGROUND

Data concerning hemodynamic status prior to and after carotid endarterectomy (CEA) in symptomatic and asymptomatic patients is insufficient. Transcranial Doppler (TCD) provides information regarding compensatory collateral flow as well as mechanisms of cerebral autoregulation in patients with carotid stenosis.

PATIENTS AND METHODS

Forty eight symptomatic and 81 asymptomatic patients with unilateral severe carotid stenosis were examined by TCD before and in early postoperative period after CEA.

RESULTS

Cigarette smoking was the only risk factor significantly more frequent in symptomatic patients. Preoperative anterior cerebral artery (ACA) and middle cerebral artery (MCA) asymmetry, basilar artery velocity and number of ophthalmic arteries with reversed flow, were not significantly different between the two groups. Pulsatility index, cerebrovascular reactivity and flow acceleration on the side of stenosis were significantly lower in symptomatic patients. After surgery there was a significant improvement of all TCD parameters in symptomatic as well as asymptomatic patients.

CONCLUSIONS

The exhausted ability of cerebral autoregulation is an important factor differentiating between symptomatic and asymptomatic patients with severe carotid stenosis. Successful surgery provides good recovery of cerebral hemodynamics in both symptomatic and asymptomatic patients.

Cognitive dysfunction in congestive heart failure: transcranial Doppler evidence of microembolic etiology

Cognitive symptoms are common in patients with congestive heart failure (CHF) and are usually attributed to low cerebral blood flow. In the present study, we aimed to evaluate global cognitive function (Mini Mental State Exam MMSE) in relation to both cardiac function (evaluated by echocardiogram) and cerebrovascular hemodynamics (evaluated by transcranial Doppler TCD) in CHF patients. In 83 patients studied, no correlation was found between echocardiographic parameters and MMSE scores. In contrast, a significant correlation was found between right middle cerebral artery (RMCA) mean flow velocity and MMSE score (r=0.231 p=0.039), as well as between RMCA pulsatility index and MMSE score (r s= -0.292 p=0.015). After excluding patients with a previous history of stroke, only RMCA pulsatility index correlated with MMSE score (r s=-0,314 p=0,007). The relationship between high cerebrovascular resistance and worse cognitive scores suggest that microembolism may be responsible for a significant proportion of cognitive symptoms in CHF patients.

Difference in recognition of right and left hemispheric stroke

Symptoms of cerebrovascular events differ depending on the hemisphere in which the lesion arises, thereby affecting disease recognition and management. We aimed to establish whether left and right hemispheric strokes are unequally distributed in inpatients. We obtained data from a large hospital-based stroke registry in Germany. 11,328 patients (56%) had left hemispheric events and 8769 (44%) had right-sided lesions (p<0.0001). Age, stroke severity, and time from symptom onset to admission were significantly associated with left hemispheric stroke, suggesting a selection effect. Difficulties in recognition of symptoms due to right hemispheric stroke challenge efforts to optimise stroke management, particularly in the critical early hours of stroke.