Acute cerebral infarcts in multiple arterial territories associated with cardioembolism

OBJECTIVES

It is generally believed that cardioembolism is the main cause of multiple acute cerebral infarcts (MACI). However, there are surprisingly few DWI studies and results are conflicting. Based on a large prospective study we hypothesized that MACI are associated with cardioembolism.

MATERIALS AND METHODS

We studied 2697 patients with acute cerebral infarcts between February 2006 and October 2013 who were prospectively registered in The Bergen NORSTROKE Registry. Among them, 2220 (82.3%) patients underwent magnetic resonance imaging (MRI) and 2125 (96%) of these 2220 patients had DWI lesions. Only patients with DWI lesions were included. MACI were defined as at least two DWI lesions in at least two different arterial territories.

RESULTS

MACI were detected in 187/2125 (8.8%) patients with DWI lesions. MACI patients were older and more often females. MACI were associated with cardioembolism (P = 0.042), especially atrial fibrillation (P = 0.002). Other associations were symptomatic internal carotid artery (ICA) stenosis (P = 0.014), asymptomatic ICA stenosis (P = 0.036), and higher NIHSS score on admission (P < 0.001). Among patients with no cardioembolism, 34 (35%) with MACI had symptomatic ICA stenosis versus 268 (25.0%) with non-MACI (P = 0.037); 20 (20%) with MACI had asymptomatic ICA stenosis versus 134 (13%) with non-MACI (P = 0.031). In the logistic regression analysis, cardiac embolism and symptomatic ICA stenosis were independently associated with MACI.

CONCLUSIONS

Acute cerebral infarcts in more than one arterial territory occur among almost 10% of the patients and are associated with cardioembolism.

NOR-SASS (Norwegian Sonothrombolysis in Acute Stroke Study): Randomized Controlled Contrast-Enhanced Sonothrombolysis in an Unselected Acute Ischemic Stroke Population

Background and Purpose—

The NOR-SASS (Norwegian Sonothrombolysis in Acute Stroke Study) aimed to assess effect and safety of contrast-enhanced ultrasound treatment in an unselected acute ischemic stroke population.

Methods—

Patients treated with intravenous thrombolysis within 4.5 hours after symptom onset were randomized 1:1 to either contrast-enhanced sonothrombolysis (CEST) or sham CEST. A visible arterial occlusion on baseline computed tomography angiography was not a prerequisite for inclusion. Pulse-wave 2 MHz ultrasound was given for 1 hour and contrast (SonoVue) as an infusion for ≈30 minutes. Magnetic resonance imaging and angiography were performed after 24 to 36 hours. Primary study end points were neurological improvement at 24 hours defined as National Institutes of Health Stroke Scale score 0 or reduction of ≥4 National Institutes of Health Stroke Scale points compared with baseline National Institutes of Health Stroke Scale and favorable functional outcome at 90 days defined as modified Rankin scale score 0 to 1.

Results—

A total of 183 patients were randomly assigned to either CEST (93 patient) or sham CEST (90 patients). The rates of symptomatic intracerebral hemorrhage, asymptomatic intracerebral hemorrhage, or mortality were not increased in the CEST group. Neurological improvement at 24 hours and functional outcome at 90 days was similar in the 2 groups both in the intention-to-treat analysis and in the per-protocol analysis.

Conclusions—

CEST is safe among unselected ischemic stroke patients with or without a visible occlusion on computed tomography angiography and with varying grades of clinical severity. There was, however, statistically no significant clinical effect of sonothrombolysis in this prematurely stopped trial.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01949961.

A stress-related explanation to the increased blood pressure and its course following ischemic stroke

Background

A hypertensive response after ischemic stroke is frequent, yet its pathophysiology is unknown. Mechanisms related to local ischemic damage, major vascular occlusion, and psychological stress due to acute illness have been proposed. We assessed the natural course of blood pressure (BP) within the first 24 h in groups of ischemic stroke patients with different characteristics. We hypothesized that a consistent BP reduction, regardless of stroke location, time window from debut to admission and presence of persistent vascular occlusion, would favor a stress-related mechanism as an important cause of the hypertensive response after ischemic stroke.

Methods

Ischemic stroke patients (n=1067) were prospectively registered, and BP was measured on admission and <3 h, 3–6 h, 6–12 h and 12–24 h after admission. Patients were categorized according to the location of diffusion-weighted imaging (DWI) lesions (cortical, large subcortical, mixed cortico-subcortical, lacunar, cerebellar, brain stem or multiple), time window (admitted within or after 6 h of symptom onset) and presence of persistent proximal middle cerebral artery (MCA) occlusion versus normal findings on magnetic resonance angiography (MRA) at 24 h.

Results

A reduction in systolic BP and diastolic BP from baseline to 12–24 h was found across all DWI locations except for diastolic BP in cerebellar (P=0.072) lesions. Apart from diastolic BP in patients with normal MRA findings at 24 h (P=0.060), a significant fall in systolic BP and diastolic BP at 12–24 h was registered, irrespective of whether patients were admitted within 6 h or after 6 h of stroke onset or had persistent MCA occlusion versus normal MRA findings.

Conclusion

We found a relatively consistent decline in BP within 24 h after admission across different stroke locations in patients admitted within or after 6 h of stroke onset and in patients with persistent MCA occlusion. Our findings suggest that a systemic factor such as psychological stress may be an important contributor to the frequently elevated BP on admission in patients with ischemic stroke.

Time patterns in multiple acute cerebral infarcts

Background

Multiple acute cerebral infarcts in different arterial territories may be caused by several emboli concurrently or successively.

Aim and/or hypothesis

We hypothesized that the time from stroke onset to magnetic resonance imaging may shed light on underlying mechanisms of multiple acute cerebral infarcts.

Methods

This is a prospective observational cohort study involving 2697 ischemic stroke patients conducted at Haukeland University Hospital between February 2006 and October 2013. Only patients with diffusion-weighted imaging lesions in more than one arterial territory (left or right anterior circulation or posterior circulation) were included. The time from stroke onset to magnetic resonance imaging was registered and correlated with the etiology of multiple acute cerebral infarcts in each patient.

Results

We reviewed 2697 consecutive patients and 2220 (82%) underwent magnetic resonance imaging. Among these 2125 (96%) had diffusion-weighted imaging lesions. We found 187 multiple acute cerebral infarct patients who were then included in the study. There was positive correlation (0.20; p < .001) between time to magnetic resonance imaging and frequency of multiple acute cerebral infarcts caused by internal carotid stenosis. There was no correlation (−.02) between time to magnetic resonance imaging and frequency of multiple acute cerebral infarcts caused by cardiogenic embolism.

Conclusions

Multiple acute cerebral infarcts associated with cardiogenic embolism seem to happen concurrently as a shower of emboli whereas multiple acute cerebral infarcts associated with internal carotid artery stenosis seem to occur successively separated by hours or days.

U-curve relation between cholesterol and prior ischemic stroke

OBJECTIVES

Previous prospective studies on ischemic stroke patients have shown conflicting results concerning the association between cholesterol level and patient outcome. We aimed to investigate the relation between cholesterol level and prior ischemic stroke. We hypothesized that acute ischemic stroke patients with increased cholesterol on admission more frequently had experienced prior ischemic stroke.

METHODS

All consecutive patients with acute ischemic stroke (the index stroke) admitted to the Stroke Unit, Department of Neurology, Haukeland University Hospital between February 2006 and October 2013 were prospectively registered in The Bergen NORSTROKE Registry. On admission, cholesterol, low-density lipoprotein, and high-density lipoprotein levels were measured and prior ischemic stroke, risk factors, and medication were registered. Patients with prior versus no prior ischemic stroke were compared regarding risk factors, cholesterol levels, and use of statins on admission for the index stroke. Only patients with available cholesterol values measured on admission were included in the analyses.

RESULTS

Of the 2,514 included patients admitted with acute ischemic stroke, 429 (17%) patients had prior ischemic stroke. We found a U-curve relationship between the relative frequency of prior ischemic stroke and cholesterol level. Lower frequency of prior ischemic stroke was associated with high cholesterol level on admission up to 5.5 mmol/L. For cholesterol levels higher than this, the opposite was true. These associations included all patients and statin-naive patients. For patients using statin there was a declining relative frequency of prior ischemic stroke from low to high cholesterol levels.

CONCLUSION

Our hypothesis was falsified. The association between lower cholesterol levels and higher frequency of prior ischemic stroke in patients with cholesterol <5.5 mmol/L cannot be solely an effect of aggressive statin treatment in patients with prior ischemic stroke, as the association pertained also to patients who did not use statin.

A Family History of Stroke Is Associated with Increased Intima-Media Thickness in Young Ischemic Stroke - The Norwegian Stroke in the Young Study (NOR-SYS)

Background and Purpose

Positive family history (FH+) of cardiovascular disease (CVD) is a risk factor for own CVD. We aimed to analyze the effect of different types of FH (stroke, coronary heart disease (CHD), peripheral artery disease (PAD) on carotid intima-media thickness (cIMT) in young and middle-aged ischemic stroke patients.

Methods

First-degree FH of CVD was assessed in ischemic stroke patients ≤ 60y using a standardized interview. Carotid ultrasound was performed and far wall cIMT in three carotid artery segments was registered, representing the common carotid (CCA-IMT), carotid bifurcation (BIF-IMT) and the internal carotid artery (ICA-IMT). Measurements were compared between FH+ and FH negative groups and stepwise backward regression analyses were performed to identify factors associated with increased cIMT.

Results

During the study period 382 patients were enrolled, of which 262 (68%) were males and 233 (61%) reported FH of CVD. Regression analyses adjusting for risk factors revealed age as the most important predictor of cIMT in all segments. The association between FH+ and cIMT was modified by age (p = 0.014) and was significant only regarding ICA-IMT. FH+ was associated with increased ICA-IMT in patients aged < 45y (p = 0.001), but not in patients ≥ 45y (p = 0.083). The association with ICA-IMT was present for a FH of stroke (p = 0.034), but not a FH+ of CHD or PAD.

Conclusions

FH of stroke is associated with higher ICA-IMT in young ischemic stroke patients. Subtyping of cardiovascular FH is important to investigate heredity in young ischemic stroke patients.

Trial Registration

ClinicalTrials.gov NCT01597453

Serial NIHSS scores in patients with acute cerebral infarction

AIM

To study time course of neurological deficits in patients with acute cerebral infarction admitted shortly after stroke onset.

METHODS

Serial NIHSS scores were obtained whenever feasible in patients admitted because of cerebral infarction within 3 h of symptom onset. Patients receiving and not receiving thrombolysis were compared. Short-term outcome was defined as NIHSS score and modified Rankin score 7 days after stroke onset. The hyperacute phase was defined as the time between stroke onset and the 6- to 9-h interval after stroke onset, acute phase as the time between the 6- to 9-h interval and the 21 to 27-h interval, and the subacute phase as the time between the 21- to 27-h interval and 7 days after stroke onset.

RESULTS

Serial NIHSS scores were obtained in 552 patients within three hours of stroke onset. There was a significant improvement (P < 0.001) comprising 62% of the total improvement in the hyperacute phase. There was no significant improvement in the acute phase and a small significant improvement in the subacute phase (P < 0.01).

CONCLUSION

Our study demonstrates a hyperacute phase with rapid improvement probably due to early recanalization, an acute phase with no significant improvement and slow improvement in the subacute phase. Different pathophysiological mechanisms are likely involved in the different phases.

Recurrent ischemic stroke is associated with the burden of risk factors

AIM

To determine the characteristics of acute ischemic stroke patients admitted to hospital with history of prior ischemic stroke(s). We hypothesized that there is an association between the number of risk factors and prior ischemic stroke irrespective of age.

METHODS

All patients with acute ischemic stroke admitted to Haukeland University Hospital between 2006 and 2013 were registered in the NORSTROKE database. Variables included prior ischemic stroke(s) (based on self-report and patient records), risk factors, TOAST classification, and CT and MRI findings. Comparison was made between patients with prior ischemic stroke and first-ever ischemic stroke. Multivariate analyses were performed.

RESULTS

In total, 2697 patients were included and 461 (17.1%) had a history of prior ischemic stroke(s). Logistic regression analyses showed that prior ischemic stroke was associated with the number of risk factors, leukoaraiosis, hypertension, atrial fibrillation, and atherosclerosis.

CONCLUSION

History of prior ischemic stroke in patients with acute ischemic stroke was associated with the burden of risk factors, atherosclerosis, and atrial fibrillation compared to first-ever ischemic stroke. This has important implications for secondary preventive treatment.

Age dependency of ischaemic stroke subtypes and vascular risk factors in western Norway: the Bergen Norwegian Stroke Cooperation Study

OBJECTIVES

Age dependency of acute ischaemic stroke aetiology and vascular risk factors have not been adequately evaluated in stroke patients in Norway. Aims of this study were to evaluate how stroke subtypes and vascular risk factors vary with age in a western Norway stroke population.

MATERIALS AND METHODS

Patients aged 15-100 years consecutively admitted to our neurovascular centre with acute ischaemic stroke between 2006 and 2012 were included. The study population was categorized as young (15-49 years), middle-aged (50-74 years) or elderly (≥ 75 years). Stroke aetiology was defined by TOAST criteria. Risk factors and history of cardiovascular disease were recorded.

RESULTS

In total, 2484 patients with acute cerebral infarction were included: 1418 were males (57.3%). Mean age was 70.8 years (SD ± 14.9), 228 patients were young, 1126 middle-aged, and 1130 were elderly. The proportion of large-artery atherosclerosis and of small-vessel occlusion was highest among middle-aged patients. The proportion of cardioembolism was high at all ages, especially among the elderly. The proportion of stroke of other determined cause was highest among young patients. Some risk factors (diabetes mellitus, active smoking, angina pectoris, prior stroke and peripheral artery disease) decreased among the elderly. The proportions of several potential causes increased with age.

CONCLUSION

The proportion of stroke subtypes and vascular risk factors are age dependent. Age 50-74 years constitutes the period in life where cardiovascular risk factors become manifest and stroke subtypes change.

Early neurological worsening in acute ischaemic stroke patients

Objectives

Neurological worsening in acute ischaemic stroke patients is common with significant morbidity and mortality.

Aims

To determine the factors associated with early neurological worsening within the first 9 h after onset of acute ischaemic stroke.

Materials & methods

The National Institute of Health Stroke Scale (NIHSS) was used to assess stroke severity. Early neurological worsening was defined as NIHSS score increase ≥4 NIHSS points within 9 h of symptom onset compared to NIHSS score within 3 h of symptom onset. Patients with early neurological worsening were compared to patients with unchanged or improved NIHSS scores.

Results

Of the 2484 patients admitted with ischaemic stroke, 552 patients had NIHSS score within 3 h of symptom onset, and 44 (8.0%) experienced early neurological worsening. The median NIHSS on admission was 8.4 in both groups. Early neurological worsening was associated with low body temperature on admission (P = 0.01), proximal compared to distal MCA occlusion (P = 0.007) and with ipsilateral internal carotid artery stenosis >50% or occlusion (P = 0.04). Early neurological worsening was associated with higher NIHSS day 7 (P < 0.001) and higher mortality within 7 days of stroke onset (P = 0.005).

Conclusions

Early neurological worsening has serious consequences for the short‐term outcome for patients with acute ischaemic stroke and is associated with low body temperature on admission, and with extracranially and intracranially large‐vessel stenosis or occlusion.

Cancer-Associated Stroke: The Bergen NORSTROKE Study

Background

Underlying malignancy can cause ischemic stroke in some patients. Mechanisms include the affection of the coagulation cascade, tumor mucin secretion, infections and nonbacterial endocarditis. The release of necrotizing factor and interleukins may cause inflammation of the endothelial lining, creating a prothrombotic surface that triggers thromboembolic events, including stroke. The aims of this study were to assess the occurrence of cancer in patients who had recently suffered an ischemic stroke and to detect possible associations between stroke and cancer subtypes.

Methods

All ischemic stroke patients registered in the Norwegian Stroke Research Registry (NORSTROKE) as part of the ongoing Bergen NORSTROKE study were included. Blood samples were obtained on admission. Stroke etiology was determined by the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria, and the severity of stroke was defined according to the National Institute of Health Stroke Scale score. Information about cancer disease after stroke was obtained from patient medical records and The Cancer Registry of Norway.

Results

From a total of 1,282 ischemic stroke patients with no history of cancer, 55 (4.3%) patients were diagnosed with cancer after stroke. The median time from stroke onset to cancer diagnosis was 14.0 months (interquartile range 6.2-24.5). Twenty-three (41.8%) patients were diagnosed with cancer within 1 year and 13 (23.6%) within 6 months. The most common cancer type was lung cancer (19.0%). By Cox regression analysis, cancer after stroke was associated with elevated D-dimer levels on admittance (p < 0.001), age (p = 0.01) and smoking (p = 0.04).

Conclusions

Cancer-associated stroke is rare, and routine investigation for cancer seems unwarranted in acute ischemic stroke. However, in stroke patients with elevated levels of blood coagulation factors, C-reactive protein, higher age and a history of smoking, underlying malignancy should be considered. Our study suggests that an unknown stroke etiology does not predict malignancy.

Comparing withdrawal and non-withdrawal of life-sustaining treatment among patients who died from stroke

BACKGROUND

In severe stroke, a decision to withdraw life-sustaining treatment is sometimes made in cooperation with the family. The aim of this study was to study the time from withdrawing life-sustaining treatment to death in patients with severe ischemic or hemorrhagic stroke.

METHODS

In total, 2,506 patients with stroke admitted to Haukeland University Hospital between 2006 and 2011 were prospectively registered in the Bergen NORSTROKE database. Risk factors, stroke severity, etiology, and blood analyses were registered. Retrospectively, the patients' records were examined to determine the number of days from withdrawing all life-sustaining treatment to death in patients who died from severe stroke during the hospital stay.

RESULTS

Life-sustaining treatment was withheld in 50 patients with severe stroke. Median time to death after withdrawing life-sustaining treatment was 4 days, and a quarter lived at least 1 week (range =1-11 days). Cox regression analyses showed that short time from withdrawing life-sustaining treatment to death was associated with high age (Hazard ratio [HR] =1.05, P=0.07), male sex (HR =2.9, P=0.01), high C-reactive protein on admission (HR =1.01, P=0.001), and hemorrhagic stroke (versus ischemic stroke, HR =1.5, P=0.03).

CONCLUSION

One week after withdrawing life-sustaining treatment, a quarter of our patients with severe stroke remained alive. Short time to death was associated with high age, male sex, hemorrhagic stroke, and high C-reactive protein on admittance.

Can the cardiovascular family history reported by our patients be trusted? The Norwegian Stroke in the Young Study

Background and purpose

Family history (FH) is used as a marker for inherited risk. Using FH for this purpose requires the FH to reflect true disease in the family. The aim was to analyse the concordance between young and middle‐aged ischaemic stroke patients' reported FH of cardiovascular disease (CVD) with their parents' own reports.

Methods

Ischaemic stroke patients aged 15–60 years and their eligible parents were interviewed using a standardized questionnaire. Information of own CVD and FH of CVD was registered. Concordance between patients and parents was tested by kappa statistics, sensitivity, specificity, predictive values and likelihood ratios. Regression analyses were performed to identify patient characteristics associated with non‐concordance of replies.

Results

There was no difference in response rate between fathers and mothers (P = 0.355). Both parents responded in 57 cases. Concordance between patient and parent reports was good, with kappa values ranging from 0.57 to 0.7. The patient‐reported FH yielded positive predictive values of 75% or above and negative predictive values of 90% or higher. The positive likelihood ratios (LR+) were 10 or higher and negative likelihood ratios (LR−) were generally 0.5 or lower. Interpretation regarding peripheral arterial disease was limited due to low parental prevalence. Higher age was associated with impaired concordance between patient and parent reports (odds ratio 1.05; 95% confidence interval 1.01–1.09; P = 0.020).

Conclusions

The FH provided by young and middle‐aged stroke patients is in good concordance with parental reports. FH is an adequate proxy to assess inherited risk of CVD in young stroke patients.

Continuous Local Intra-Arterial Nimodipine for the Treatment of Cerebral Vasospasm

Vasospasm (VSP) is one of the major causes for prolonged neurologic deficit in patients with aneurysmal subarachnoid hemorrhage. Few case series have reported about continuous local intra-arterial nimodipine administration (CLINA) in refractory VSP. We report our experience with CLINA in a patient with refractory cerebral VSP.

A pragmatic approach to sonothrombolysis in acute ischaemic stroke: the Norwegian randomised controlled sonothrombolysis in acute stroke study (NOR-SASS)

BACKGROUND

Ultrasound accelerates thrombolysis with tPA (sonothrombolysis). Ultrasound in the absence of tPA also accelerates clot break-up (sonolysis). Adding intravenous gaseous microbubbles may potentiate the effect of ultrasound in both sonothrombolysis and sonolysis. The Norwegian Sonothrombolysis in Acute Stroke Study aims in a pragmatic approach to assess the effect and safety of contrast enhanced ultrasound treatment in unselected acute ischaemic stroke patients.

METHODS/DESIGN

Acute ischaemic stroke patients ≥ 18 years, with or without visible arterial occlusion on computed tomography angiography (CTA) and treatable ≤ 4(½) hours after symptom onset, are included in NOR-SASS. NOR-SASS is superimposed on a separate trial randomising patients with acute ischemic stroke to either tenecteplase or alteplase (The Norwegian Tenecteplase Stroke Trial NOR-TEST). The NOR-SASS trial has two arms: 1) the thrombolysis-arms (NOR-SASS A and B) includes patients given intravenous thrombolysis (tenecteplase or alteplase), and 2) the no-thrombolysis-arm (NOR-SASS C) includes patients with contraindications to thrombolysis. First step randomisation of NOR-SASS A is embedded in NOR-TEST as a 1:1 randomisation to either tenecteplase or alteplase. Second step NOR-SASS randomisation is 1:1 to either contrast enhanced sonothrombolysis (CEST) or sham CEST. Randomisation in NOR-SASS B (routine alteplase group) is 1:1 to either CEST or sham CEST. Randomisation of NOR-SASS C is 1:1 to either contrast enhanced sonolysis (CES) or sham CES. Ultrasound is given for one hour using a 2-MHz pulsed-wave diagnostic ultrasound probe. Microbubble contrast (SonoVue®) is given as a continuous infusion for ~30 min. Recanalisation is assessed at 60 min after start of CEST/CES. Magnetic resonance imaging and angiography is performed after 24 h of stroke onset. Primary study endpoints are 1) major neurological improvement measured with NIHSS score at 24 h and 2) favourable functional outcome defined as mRS 0-1 at 90 days.

DISCUSSION

NOR-SASS is the first randomised controlled trial designed to test the superiority of contrast enhanced ultrasound treatment given ≤ 4(½) hours after stroke onset in an unselected acute ischaemic stroke population eligible or not eligible for intravenous thrombolysis, with or without a defined arterial occlusion on CTA. If a positive effect and safety can be proven, contrast enhanced ultrasound treatment will be an option for all acute ischaemic stroke patients. EudraCT No 201200032341; www.clinicaltrials.gov NCT01949961.

III-V-on-silicon anti-colliding pulse-type mode-locked laser

An anti-colliding pulse-type III-V-on-silicon passively mode-locked laser is presented for the first time based on a III-V-on-silicon distributed Bragg reflector as outcoupling mirror implemented partially underneath the III-V saturable absorber. Passive mode-locking at 4.83 GHz repetition rate generating 3 ps pulses is demonstrated. The generated fundamental RF tone shows a 1.7 kHz 3 dB linewidth. Over 9 mW waveguide coupled output power is demonstrated.