Post on 24-Jun-2020
Management of stroke acute: a
review of current evidence
Dr Julie Considine
Senior Research Fellow
Deakin University-Northern Health Clinical Partnership, Victoria, Australia
Definitions
Stroke
> acute neurological injury that is caused by interruption to
blood flow to an area of the brain
> classified according to cause
• ischaemic stroke (80%)
• haemorrhagic stroke (20%)
TIA
> brief episode of neurologic dysfunction caused by focal
brain or retinal ischemia, with clinical symptoms typically
lasting less than one hour, and without evidence of acute
infarction
> move away from old definition
• neurological deficit caused by focal brain ischemia that completely
resolves within 24 hours
Causes
Ischaemic stroke
> thrombotic stroke
> embolic stroke
> hypoperfusion
Haemorrhagic stroke
> most common cause: hypertension
Pathophysiology
Ischaemic stroke
> cerebral injury is directly related to decreased blood
supply
> cells die centre of the affected area
> affected area is surrounded by an area where injury to
the cells is potentially reversible (penbumra)
Haemorrhagic stroke
> cerebral injury occurs as a result of
• increased intracranial pressure
• local compression
• decreased perfusion
Risk management
Risk stratification for stroke
> progression of TIA to stroke significant mortality &
morbidity
> risk of stroke after TIA
• 4% to 8% in the first month
• 12% to 13% in the first year
Aplin 2004
Patient related risk factors for stroke
> non-modifiable
• age / male gender / positive family Hx
> modifiable
• hypertension / risk factors for atherosclerosis
• cardiac risk factors / carotid stenosis or carotid bruit (blockage) in
asymptomatic patients
Risk management
Risk stratification for stroke following TIA> ABCD2 tool - highly predictive for stroke after TIA
score from maximum 6 pts 0-3 points: low risk
4-5 points: moderate risk
6-7 points: high risk
Rothwell, et al. 2005; Johnson et al 2007
Age 60 yrs = 1 pt
Blood pressure SBP>140 mmHg and/or DBP90
mmHg = 1 pt
Clinical Hx unilateral weakness = 2 pts
speech involvement without
weakness = 1 pt
Duration > 60 mins = 2 pts
10-59 mins = 1 pt
Diabetes Hx diabetes = 1 pt
Signs & symptoms
Signs and symptoms of stroke
> are variable
> depend on the area of the brain affected
> clinical differentiation between ischaemic &
hemorrhagic stroke is unreliable
> haemorrhagic stroke more commonly associated with
• history of prolonged hypertension
• sudden onset of symptoms - headache / vomiting / collapse
• history of anticoagulant medications
Signs & symptoms
Initial assessment
Stroke
> is a medical emergency
> accurate assessment of onset of symptoms is
important
> early recognition, diagnosis, treatment & referral to
specialist services
• improves patient outcomes
• prevents complications
Triage
> actual or potential stoke is a time critical presentation
> use ‘FAST’ criteria and patients with high risk features
of TIA (ABCD2) to inform triage decisions
Airway / Breathing
> ensure patent airway
• position
• use of airway adjuncts - oropharygeal / nasopharyngeal
• intubation if decreased conscious state
> assess respiratory status
• respiratory rate, respiratory effort, SpO2,
> prevent / treat hypoxia
• hypoxia increases cerebral injury
• ensure adequate ventilation & oxygenation
> stroke patients have lower oxygen levels (SpO2 ) than
controls
• upright position
• supplemental oxygen if SpO2<95%
• oxygen controversial in non-hypoxic patients
Circulation> assess circulation
• heart rate, blood pressure, cardiac rhythm
> aim to optimise cerebral perfusion
• minimise infarct size / cerebral injury
> hypotension
• is uncommon in stroke
• should be treated aggressively as it compromises cerebral
perfusion
> hypertension
• common physiological response to preserve cerebral perfusion
pressure
• aggressive blood pressure reduction is NOT recommended
• use of oral or sublingual agents is NOT recommended
• exclude or treat other causes for hypertension : pain, vomiting or
urinary retention
Circulation
> ECG abnormalities are common
• 60% of patients with cerebral infarction
• 50% of patients with intracerebral haemorrhage
• 75% of patients with acute stroke have T wave inversion
> cardiac arrhythmias can occur from
• increased sympathetic tone
• decreased parasympathetic tone
• catecholamine release
> should be performed to identify
• sources of cardiogenic emboli - atrial fibrillation or recent AMI
(heart attack)
• signs of pre-existing cardiac disease
Disability (neurological status)
> assess conscious state
• Glasgow Coma Score
> optimise intracranial pressure
• ICP rises quickly after haemorrhagic stroke
• can take up to 48hrs to manifest in ischaemic stroke
• it is unclear if aggressive Mx of increased ICP improves
outcome in stroke
• early reduction in conscious state is poor prognostic indicator
Blood glucose
> monitor blood glucose level
> exclude hypoglycaemia as cause for symptoms
> exclude / identify hyperglycaemia • 20-50% of stroke patients are hyperglycaemic in ED
• 8-20% of stroke patients have diabetes
• due to known or unknown diabetes / stress response
> hyperglycaemia is associated with increased cerebral
injury and poor outcomes
> Weir et al. (1997) • examined effect of BSL on stroke outcomes
• BLS > 8 mmol/L was independent predictor of poor outcome
> elevated BSL should be actively corrected
Temperature
> sources of fever / hyperthermia following stroke
• infection preceding stroke - pneumonia / UTI /
• thromboembolism
> fever increases infarct size & mortality
> meta-analysis: Hajat et al, 2000
• 3790 patients in 9 studies
• 19% increase in mortality in febrile stroke patients
> mechanisms of cerebral injury related to pyrexia
• neurotransmitters associated with poor cerebral outcomes -
glutamate, g-aminobutyric acid, glycine
• free radical production
• blood-brain barrier is temperature-sensitive so increased protein
transfer across the blood-brain barrier during hyperthermia
• hyperthermia also increases cerebral metabolism
Swallowing assessment
> nil orally until swallowing is assessed
• impaired swallowing is associated with increased mortality
> early swallowing assessment is important
• prevent aspiration
• guide decisions about oral intake
• reduce the need for IV fluid or nasogastric tube feeds
> swallowing assessment should be performed by
trained personnel
• ideally speech pathologists
• dysphagia screening tools available
• assessment of gag is unreliable indicator of swallowing
Imaging> non-contrast CT
• most common investigation for completed stroke
• current guidelines recommend CT performed within 24 hours of
symptom onset
• usually occurs sooner, particularly if thrombolysis is treatment
option
• performed to exclude intracerebral haemorrhage prior to
anticoagulation or thrombolytic therapy
• many will be normal in the first few hours following ischaemic
stroke
> MRI
• superior to CT: identify early signs of infarction
• inferior to CT: identify haemorrhagic causes of stroke
Drug therapy for ischaemic stroke
Aspirin
> administration < 48 hours of onset of symptoms
• reduces early death & recurrent stroke
• if patient is unable to swallow, Aspirin should be administered
via an alternative route - NGT
• intracerebral haemorrhage should be excluded by CT scan prior
to Aspirin
Drug therapy for ischaemic stroke
Anticoagulation
> no evidence that anticoagulation decreases
• morbidity or mortality
• early recurrent stroke
> routine use of low molecular weight heparin is not
recommended for Mx of ischaemic stroke
• anticoagulation benefit for patients with atrial fibrillation &
stroke secondary to cardiogenic emboli
• best time to commence anticoagulation in these patients is
unknown
> prior to anticoagulation
• exclude intracerebral haemorrhage by CT scan
• obtain neurological consultation
• should occur prior to commencement of heparin
Drug therapy for ischaemic stroke
Thrombolysis> use in stroke still controversial in some circles but
routine in others
> current evidence • until recently - no support for use of thrombolysis in acute
ischaemic stroke beyond 3 hours of symptoms
• in 2008, two studies showed safe use of thrombolysis in acute
ischaemic stroke up to 4.5 hours of symptoms
• further research & advances in neuro-imaging may change the
criteria in future
Drug therapy for ischaemic stroke
Thrombolysis - NINDS (1995)
Drug therapy for ischaemic stroke
Thrombolysis - NINDS(1995)
> randomized, double-blind trial of t-PA for ischemic
stroke within 3 hrs (Part 1: n = 291 / Part 2: n = 333)
> results
• neurologic improvement at 24 hours: no difference
• patients treated with t-PA were at least 30% more likely to have
minimal or no disability at 3 mths
• symptomatic ICH rates within 36 hours : higher with
thrombolysis
6.4% vs 0.6%, p <0.001
• mortality @ 3mths : no difference
17% vs 21%, p = 0.30
Drug therapy for ischaemic stroke
Thrombolysis - NINDS reanalysis (Ingall, 2004)
> concerns about results from NIDS study
> data re-analysed by independent group
> results
• there were subgroup differences in baseline stroke severity but
the differences did not affect results
• symptomatic ICH rates: higher with thrombolysis
6.4% vs 0.6% (same as original study)
• favorable outcomes: higher with thrombolysis
OR = 2.1, 95% CI, 1.5 to 2.9
> conclusion
• use of t-PA for acute ischemic stroke < 3 hours of onset was
supported
Drug therapy for ischaemic stroke
Thrombolysis - Hacke et al. / Wahlgren et al. (2008)
Drug therapy for ischaemic stroke
Thrombolysis - Hacke et al. (2008)European Cooperative Acute Stroke Study (ECASS) group
> compared patients with acute ischaemic stroke treated
with alteplase 3h to 4·5h after symptoms versus
placebo (n = 821)
> results
• favourable outcome* @ 3 mths was higher with thrombolysis
52.4% vs. 45.2%, p = 0.04
• ICH rates: higher with thrombolysis
- any ICH: 27.0% vs. 17.6%, p = 0.001;
- symptomatic ICH: 2.4% vs. 0.2%, p = 0.008
• mortality: no difference
7.7% vs. 8.4%, p = 0.68
* modified Rankin score 0 or 1
Drug therapy for ischaemic stroke
Thrombolysis - Wahlgren et al. (2008)Safe Implementation of Treatments in Stroke (SITS) group
> compared patients with acute ischaemic stroke treated
with alteplase (n = 664)
• between 3h and 4·5h versus
• patients treated within 3h
> results - no differences in
• symptomatic ICH within 24 hrs
2·2% (14/649) versus 1·6% (183/11681) p = 0.24
• mortality
12·7% (70/551) versus 12·2% (1263/10 368), p = 0.72
• independence* @ 3 mths:
58·0% (314/541) versus 56·3% (5756/10231), p = 0.18
*modified Rankin scale of 0–2
Drug therapy for ischaemic stroke
Thrombolysis - current recommendations
(National Stroke Foundation Guidelines, 2007)
Drug therapy for ischaemic stroke
Thrombolysis - current recommendations
(National Stroke Foundation Guidelines, 2007)
Drug therapy for ischaemic stroke
Thrombolysis - ongoing issues> frequency of thrombolysis in acute stroke is low
> patient selection is important
• not all patients who present within 3 hrs (or 4.5hrs) will be
candidates for thrombolysis
• requires complex clinical decisions for some patients
• can be difficult to diagnose acute ischaemic stroke & exclude
subtle intracerebral haemorrhage
> local resource considerations
• imaging capabilities
• staff skills and knowledge - interpretation of images, general
care of acute stroke, specifics of thrombolysis administration,
management of complications if they occur
• infrastructure for care post thrombolysis
Mx of haemorrhagic stroke
Management
> depends on
• location / cause
• neurological deficit / patient’s clinical condition
> should include
• early neurosurgical referral for patients with potential for
surgical intervention
• Mx increased ICP
> cerebral oedema & increased ICP tend to occur more
acutely in haemorrhagic strokes
> ischaemic strokes can also have haemorrhagic
complications
Ongoing care
Stroke units
> better outcomes following stroke
> Indredavik et al (1999)
• assessed which aspects of stroke unit care resulted in better
outcomes
• 206 patients (stroke unit: n = 102, general wards: n = 104)
• analyzed measurable factors and their association discharge to
home within 6 weeks
> treatment factors that were different in stroke units
• increased use of oxygen, heparin, IV N/Saline & antipyretics
• decreased variation BP, hypotension
• hyperglycaemia / pyrexia
• all factors except glucose level were associated with discharge
to home within 6 weeks
Summary
> stroke is a medical emergency & time critical
presentation
> general management principles
• A - protect airway, prevent aspiration
• B - optimise oxygenation
• C - optimise blood pressure & cerebral perfusion, ECG
• D - optimise ICP and cerebral perfusion
• Other - blood glucose, temperature, swallowing
> Tx ischaemic stroke
• thrombolysis in specific patients
• anticoagulation in specific patients
• Aspirin
> Tx haemorrhagic stroke
• Mx increased ICP / surgical intervention