Transient Ischaemic Attacks Whom to Refer What to Expect Assessment and Management

1
Transient Ischaemic AttacksWhom to Refer?What
to Expect? Assessment and Management

• Dr Sheela Shah MD FRCP
• Consultant Stroke Physician
• Barnet General Hospital

2

• Defining TIAs
• Diagnostic Biomarkers
• Differential Diagnosis
• Vascular Risk Triage
• Special Situations (Cardioembolism, Intracranial
  and Extracranial Stenosis, Dissections, Women,
  Migraine)
• Neuroimaging and Neurovascular Imaging
• Research
• BCFHT TIA Services

3
Rapid Access to Specialist Assessment, Treatment
and Stroke Prevention

• Public Awareness Campaigns
• Interventions in Ambulance Practice
• Health Professional Education
• High Risk Triage
• Diagnosis and Treatment
• Risk Factor Management

4
TIA Definition Revisited

• No longer based on the 24 hour time frame
• Usually no structural damage in ischaemia lt 1
  hour
• 50 of TIAs usually last for lt ½ hour
• Transient neurovascular deficit lt 1 hour
• No neuroradiological change MRI-DWI /CT
  perfusion
• Absence of any Biological Markers of Neuronal
  Injury

5
Stroke / TIA Mechanisms

• Occlusion at perforator orifice
• Artery to artery embolism
• Concomitant low perfusion slows clot clearance
• Branch artery occlusion with collaterals
• Cardioembolism

6
Specific Types of Cortical Ischaemia

• Periventricular lesions SVD / Lacunar
• Subcortical lesions Vasculitis / Amyloid
• Borderzone lesions Anterior / Posterior /
  Internal
• Reversible Cerebral Vasoconstriction Syndrome
• Reversible Posterior Leucoencephalopathy Syndrome

7
Borderzone Infarcts presenting as TIAs

• 12 prevalence
• Abrupt and progressive
• Fluttering-Stuttering
• 10-20 with Hypotension / LOC / Syncope
• Motor / Sensory Hemiparesis or Aphasia
• Neuropsychiatric disturbance (Internal BZI)

8
Stroke Biomarkers

• Brain Natriuretic Peptide
• D-Dimer
• Brain Specific Protein (after 24 hours)
• MMP 9
• Glial Fibrillary Acid Protein (after 2 hr in PICH)

9
Biomarkers as Predictors of Stroke

• Multimarker Index of lt 1.3 Mimic
• Haemorrhagic Transformation risk
• Safety in Thrombolysis
• Very high in Malignant MCA infarct
• 99.85 accuracy if Ischaemic Marker is present
  and Haemorrhagic Marker is absent (BSP / BNP are
  ve GFAP is ve at onset)

10
TIA and Stroke Mimics

• Hypoglycaemia
• Todds paralysis / Seizure
• SOL
• Acute SDH
• Migraine
• MS
• Toxic Encephalopathy / Acute Delirium
• Conversion reaction / Psychosis

11
Who? Indications for Evaluation

• High Risk TIA / Minor Disability Stroke
• 7-day stroke risk ater TIA 10
• Prevention of Heart Attacks
• Prevention of Strokes
• Prevention of Dementia
• Confirmation of the diagnosis
• Identification of site of lesion and its cause
• Cryptogenic strokes in young patients
• Familial and rarer cause (vasculitis, avm)

12
Cumulative Vascular Risk Triage

• ABCD 2 score gt 4 / 7 High Risk TIA
• Age 0 lt 60 years of age 1 gt 60 years of age
  
• BP 0 lt140/90 mm 1 gt140/90 mm or gt140 mm
  Systolic or gt90 mm Diastolic
• Clinical features 2 Unilateral weakness Face,
  Arm, Leg or / and Loss of Vision
• 1 Speech disturbance
  without other signs
• Duration of event 0 lt 9 minutes 1 10 to 59
  minutes 2 gt 60 minutes
• Diabetes 0 No Diabetes 1 Diabetes present,
  new diagnosis, treated
• Unilateral weakness
• Atrial Fibrillation
• Large Artery Disease (Carotid / Ao Arch)
• Framingham Risk Equation
• Metabolic Syndrome

13
What ? Diagnosis-Investigations-Rx

• Neuroimaging
• Cardiac and Vascular Imaging
• Arrhythmia Assessment
• Syncope Testing
• Lipid and Glycaemic Screen
• General Life-style Factor Intervention
• Education Secondary Prevention Targets

14
Neuroimaging in TIA and Stroke

• NICE MRI to confirm diagnosis or vascular
  territory (not CT)
• SIGN MRI DWI and GRE in late presenters gt 1
  week , mild deficits, small lesions and posterior
  fossa lesions
• Ischaemic lesions may take 3 hours to appear on
  MRI sometimes and CT is best for rTPA to exclude
  contraindications for thrombolysis

15
Multi-professional Roles in Preventing
Pre-hospital Delay to Rapid Access

• Media and Public Health Education
• Paramedic Education
• Stroke Assessment Tools (FAST/ROSIER)
• Triage to a Stroke Specialist Centre
• Pre-notification by Paramedics
• Partnership between LAS and Secondary care
  pathways to rapid access

16
How? Specific Measures / Interventions

• Neurovascular Evaluation
• Cardiovascular Evaluation
• Metabolic Syndrome Management
• Life-style influences

17
Role of Neurovascular USG / CA Duplex

• Isolated vascular risk factor
• Reliable surrogate marker of silent
  atherosclerosis
• Vulnerable plaque vs vulnerable population
  studies
• Aortic arch atheroma
• Plaque morphology and inflammation
• MRA / Functional Plaque Imaging

18
Carotid Plaque Imaging

• Plaque stages I (Foam) II (Fat) III
  (Pre-atheroma)
• IV (Atheroma) V Fibroatheroma VI (surface
  defect and
• haemorrhage) VII (calcified) and VIII
  (Fibrotic)
• Unstable plaque surgery causes more DWI lesions
• Unstable plaques have high risk Best Medical Rx
• High echogenicity / low heterogeneity stability
• Surgery before stage VII and VIII (ideally at IV
  - VI)

19
Symptomatic Carotid Arterial Stenosis

• Duplex within 24 hours
• CEA surgery within 24 hours (High Risk)
• Ideally within 7 days of index event (Low Risk)
• Ideally for age lt 70 years
• Stenosis of gt 50 to 99 by NASCET (men)
• Women have lower risk (gt70 to 99)
• Carotid End-Arterectomy vs. Stents (less favoured)

20
Asymptomatic CA Stenosis

• Men
• Age lt 70
• Bilateral disease
• High grade caritod stenosis
• No ipsilateral event for atleast 6 months

21
Intracranial Large Arterial
Atherosclerosis and Stenosis

• Most common cause of ischaemic strokes
• 15 annual stroke recurrence
• Progressive over time
• Multifocal disease
• Intensive medical therapy
• Antithrombotic therapy
• Angioplasty
• Stenting

22
Intracranial Stenosis

• Aggressive and highly recurrent
• Atherosclerosis of intracranial vessel
• Blocked by cardiac embolus or
• Blocked by microemboli from CA stenosis
• Association with borderzone infarction
• Association with syncope
• Haemodynamic and thromboembolic interplay
• Aspirin Statin Warfarin Exercise

23
Intracranial Large Artery Atherosclerosis
and High Stroke Risk

• Local factors vulnerable lesions, location,
  severity, number of lesions, symptomatic versus
  asymptomatic lesions, progressive despite
  treatment, plaque composition, microembolic
  signals
• Systemic factors diabetes, metabolic syndrome,
  females, genetic, impaired endogenous
  fibrinolysis, inflammation, failed antithrombotic
  therapy

24
TIA and Cardioembolism

• CHADS score for OAC
• Dilated LA / ILD recorder
• Multiple asymptomatic cortical infarcts on MRI
• PFOs and cryptogenic strokes
• PFO with Aneurysmal IAS / Thrombus
• ASD
• Watershed Lesions requiring PPM OAC

25
TIA due to Vascular Dissection

• Carotid vs Vertebrobasilar
• Subintimal vs Subadventitial
• Intradural (VA and BA) vs Extracranial (CA)
• OAC or Antiplatelet Therapy
• Treat with rTPA -/ Endovascular repair
• Duration of treatment and follow up imaging

26
Cervical and Cerebral Arterial Dissections

• 20 stroke in young adults
• 1/3 complain of local pain
• Intramural hematoma stenosis
• occlusion
• compression
  / SOL
• rupture
  (ICH/SAH)
• Best diagnosis MRI with FatSat Ti and MRA
• Bed Rest for Intracranial lesions
• Intracranial lesions ischaemia and haemorrhage

27
TIA and Migraine

• Oral Contraceptives
• Premenstrual syndrome
• 16 fold stroke risk during pregnancy/preeclampsia
• Migraineurs with aura have multiple vascular
  risks
• Endothelial and arterial dysfunction
• Prophylactic Aspirin
• Life-style advice

28
TIA in Women

• Aspirin in primary prevention
• Risk in Carotid Surgery
• Thrombolysis more effective
• Post-partum and Pre-eclampsia
• HRT risk of cerebral infarction

29
Research in Secondary Stroke Prevention

• BP target lt 120/80 mm Hg
• ACE-inh or AR 2 B ACE-inh AR 2 B
• Intensive Glycaemic Control ? Bad /? Good
• CEA for Asymptomatic CAD no benefit and NNT 100
  if complication rate is lt 3
• AF stroke risk X 5. Warf Rx INR gt 2 lt 3.5
• AF and ASA Clop (NNT 28 and NICH20)

30
Metabolic Syndrome

• BMI gt 30
• Abdominal obesity 102 cm (M), 88 cm (F)
• Hypertension
• Hyperglycaemia
• Insulin Resistance
• Atherogenic Dyslipidaemia gtgtTrig ltlt HDL
• Albumin/ Creatinine Ratio (urine) gt 30

31
Statins and Stroke

• LDL lt 2
• Total Cholesterol lt 3.5
• HDl gt 1.03 (m) and 1.3 (f)
• SPARCL 80 mg Atorva and ICH
• Rosuva superior to Placebo NNT 120
• Simva first line

32
Recent Advances (Trials and Research)

• Dronedarone anti-arrhythmic cardioversion in
  Atrial Fibrillation
• Cilostazole Phosphodiesterase Inhibitor in place
  of Aspirin
• Terutoban Thrombin Inhibitor for AF (safer than
  Ximelagatran) (PERFORM)

33
Barnet and Chase Farm Hospital Rapid Access
Referral Process

• Targeting GP practices
• Distribution of referral forms
• Daily specialist-run clinics 5/7
• Weekend arrangements
• Neuroradiology Neurovascular Liaison
• Education and Audit
• Patient Education and Empowerment

34
Success by the drivers for change

• 2006 280 referrals seen within 5 days
• 2008 360 referrals seen within 3 days
• 2009 gt 62 high risks seen/Rx in 24 hrs
• 2009 gt 80 low risks see/Rx within 7
• 2009/10/11 7/7 access to out-patient care
• .. 100 outcomes
• .. participation in research