Stroke:An Introduction

Maarten Lansberg, MD, PhDNeil Schwartz, MD, PhD

Stanford Stroke Center

Outline

• Background

• Stroke Diagnosis

• Stroke Treatment

• Stroke Prevention

What is a Stroke? (Brain Attack)

Disruption of blood flow to part of the brain caused by:

• Occlusion of a blood vessel (ischemic stroke)

OR• Rupture of a blood vessel

(hemorrhagic stroke)

Types of Stroke

6%

10%

31%

53%

84%

0% 20% 40% 60% 80% 100%

Subarachnoid

Intracerebral

Embolic

Thrombotic

Total Ischemic

IschemicHemorrhagic

Mohr JP, Caplan LR, Melski JW, et al. Neurology 1978;28:754-62

Anatomy

MR Angiogram

What happens with cutoff of blood supply?

Oxygen deprivation to nerve cells in the affected area of the brain -->

Nerve cells injured and die --> The part of the body controlled

by those nerve cells cannot function.

What Causes Ischemic Stroke?

Thrombotic

Embolic

Thrombus

Embolus

Ischemic Stroke

What happens with rupture of a blood vessel?

Oxygen deprivation to nerve cells in the affected area of the brain and local destruction of nerve cells-->

Nerve cells injured and die --> The part of the body controlled by

those nerve cells cannot function.

Intracerebral Hemorrhage

Head CT: Ischemic or Hemorrhagic Stroke?

Head CT: Ischemic or Hemorrhagic Stroke?

Stroke Impact

• 750,000 strokes per year

• Third leading cause of death(1st: heart disease, 2nd: all cancers)

– Over 160,000 deaths per year

• Over 4 million stroke survivors

1. Williams GR, Jiang JG, Matchar DB, et al. Stroke 1999; 30:2523-28.2. Hoyert DL, Kochanek KD, Murphy SL. National Vital Statistics Report 1999; 47:19.

Stroke Impact (2)

• Leading cause of adult disability– Of those who survive, 90%

have deficit• Half of all patients hospitalized

for acute neurological disease.• Stroke costs the U.S. $30 to $40

billion per year.

The Stroke Belt

Perry HM, Roccella EJ. Hypertension 1998;6:1206-15.

2. Stroke Diagnosis

Symptoms of Stroke

• Sudden numbness or weakness of face, arm or leg, especially on one side of the body

• Sudden confusion, trouble speaking or understanding

• Sudden trouble seeing from one or both eyes

• Sudden unsteadiness, dizziness, loss of balance or coordination

• Sudden severe headache with no known cause

Other Stroke Symptoms

•Also common following stroke– Depression– Other emotional problems– Memory problems

Common Stroke Patterns

• Left (Dominant) Hemisphere:– Aphasia– Right hemiparesis– Right hemisensory loss– Right visual field defect– Left gaze preference– Dysarthria– Difficulty reading, writing, or

calculating

Common Stroke Patterns (2)

• Right (Nondominant) Hemisphere:– Left hemiparesis– Left hemisensory loss– Left neglect– Left visual field defect – Right gaze preference– Dysarthria

Common Stroke Patterns (3)

• Brainstem/Cerebellum/Posterior Circulation– Motor or sensory loss in all 4 limbs– Crossed signs (face vs. body)– Limb or gait ataxia– Dysarthria– Dysconjugate gaze– Nystagmus– Amnesia– Cortical blindness

Common Stroke Patterns (4)

• Small Vessel (Lacunar) Strokes (Subcortical or Brain Stem)– Pure Motor

•Weakness of face, arm, leg– Pure Sensory

•Decreased sensation of face, arm, leg

Differential Diagnosis• Stroke (ischemic; hemorrhagic)• Intracranial mass

– Tumor– Subdural hematoma

• Seizure with persistent neurological signs• Migraine with persistent neurological signs• Metabolic

– Hyper/Hypoglycemia• Infectious

– Meningitis / Encephalitis / Cerebral abscess– Systemic

3. Stroke Treatment

Time is

Brain

EMS/ED evaluation of acute stroke

• Assure adequate airway

• Monitor vital signs

• Conduct general assessment– Evidence of trauma to head or neck– Cardiovascular abnormalities

EMS/ED evaluation of acute stroke (cont.)

• Conduct neurological examination

– Level of consciousness (Glasgow Coma Scale)

– Presence of seizure activity

– NIH Stroke Scale

ED evaluation of acute stroke: diagnostic tests

• Non-contrast Head CT• EKG• Blood Glucose• CBC, platelets, PTT, PT/INR• Serum electrolytes

t-PA therapy

tPA therapy for acute stroke

• Candidate for IV tPA?– Stroke onset < 3 hours (When was

the patient last seen at baseline ?)

• Benefit: 12 % increased chance of good recovery

• Risk: bleeding (up to 6%)

tPA exclusion criteria

– Symptoms mild or rapidly resolving– SBP > 180 or DBP > 110– Blood on head CT– History of ICH– CNS tumor or vascular malformation– Bacterial endocarditis– Known bleeding disorder– PTT > 40; PT > 15 (INR > 1.7)– Stroke within 3 months– Significant trauma in last 3 months – GI/GU/Resp hemorrhage within 21 days– Major surgery within 14 days / minor surgery

within 10 days– Peritoneal dialysis or hemodialysis– Seizure at onset of stroke– Glucose <50 or >400– Pregnant

Other therapies for acute stroke

• IV t-Pa outside the three hour window

• IA t-PA• IA mechanical

thrombolysis/thrombectomy

• Neuroprotective agents

Stroke Management

If not a candidate for acute intervention, then focus on:

– Prevention of recurrent stroke• Diagnostic evaluation for stroke etiology• Risk factor assessment

– Rehabilitation (PT/OT/SLP)

– Prevention of Complications• DVT, aspiration PNA, decubitus ulcers, falls

Diagnostic stroke evaluation• Purpose: Identify location, size, and cause of stroke• Tests may include:

– Follow-up head CT– Brain MRI/MRA– Carotid ultrasound– Cardiac echo (transthoracic or transesophageal)– Cerebral angiogram or CT angiogram– Lipid panel– Hemoglobin A1c– Hypercoagulable tests: antiphospholipid antibodies,

Protein C & S, Antithrombin III, Factor V Leiden mutation, Prothrombin 20210A mutation…

4. Stroke Prevention

Stroke survivor’s greatest risk is another stroke

3%

7%

3%

14%13% 13%

10%

2%2

4

6

8

10

12

14

16

CATS TASS CAPRIE* ESPS 2

Pe

rce

nt o

f pa

tient

s w

ith e

vent

s

Stroke Heart Attack

Albers, G.W. Neurology. 2000;14;54(5):1022-8.

* Stroke patient subgroup only (n = 6,431)

Transient Ischemic Attack (TIA)

• Stroke symptoms resolve in less than 24 hours (most resolve in < 1 hour)

• Warning sign for stroke and heart attack– One third go on to have a stroke within 5

years

• Stroke risk can be reduced

• Opportunity to prevent full stroke

• Age

• Gender (men)

• Heredity: family history of stroke, hypercoagulable states

• Race/ethnicity (e.g. African Americans)

Sacco RL, Benjamin EJ, Broderick JP, et al. Stroke: 1997;28:1507-17.

Stroke risk factorsNon - Modifiable

Stroke risk factors

Medical Conditions

• Hypertension

• Heart disease

• Atrial fibrillation

• High Cholesterol

• Diabetes

• Carotid stenosis

• Prior stroke or TIA

Behaviors Cigarette smoking Alcohol abuse Physical inactivity

Modifiable

Sacco RL. et al. Stroke. 1997;28:1507-1517 Pancioli AM et al. JAMA. 1998;279:1288-1292

How many strokes can be prevented?*

360,000

146,000

90,000

69,000

34,000

0 100,000 200,000 300,000 400,000

Heavy AlcoholUse

AF

Smoking

Cholesterol

HTN

Adapted from Gorelick PB. Arch Neurol 1995;52:347-55

*Based on an estimated 731,000 strokes annually

HypertensionJNC VII Guidelines

Lower blood pressure = Lower Risk

< 120/80

< 130/85

< 140/90

Car

diov

ascu

lar

Eve

nts

Vasan RS et al N Engl J Med 345; 1291-7, 2001

< 120/80

< 130/85

< 140/90

Car

diov

ascu

lar

Eve

nts

(%)

Progress, Lancet. 2001;358:1033-41

20

15

10

5

0 1 2 3 4

PROGRESS Trial

28% relative risk reduction

PlaceboActive

Follow-up time (years)

Str

oke

Rat

e (%

)

Blood pressure reduction following stroke

14%

10%

Risk factor modificationsfor blood lipids

National Cholesterol Education Program (NCEP) Guidelines

ConditionHyperlipidemia oratherosclerotic

disease(LDL >100 mg/dL)

Recommendation• Diet: decrease fat

and cholesterol• Exercise• Add pharmacologic

therapy: statin agents

Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. JAMA 1993;269:3015-23.

Risk factor modifications for DM

ADA Recommendations to Reduce Microvascular Complications

• Average pre-prandial glucose <120 mg/dL• Average bedtime glucose 100 to 140

mg/dL

• HbA1c <7%

1. Lukovitis TG, Mazzone T, Gorelick PB. Neuroepidemiology 1999;18:1-14.2. Diabetes Care 1998;21 (Suppl 1):1-200

Lifestyle Risk Factor ModificationsLifestyle Factor

• Cigarette Smoking

• Alcohol use

• Physical activity

• Diet

Recommendation• Counseling• Nicotine replacement therapy• Bupropion

• Up to 2 drinks/day for men, 1 drink/day for women, or lighter individuals

• Brisk activity (30 to 60 min/day)

• 5 servings/day fruit and vegetables• Limit saturated fat (<30% total energy)

Gorelick PB, Sacco RL, Smith DB, eet al. JAMA 1999;281:1112-1120.

Prevention of Blood Clot Formation

Müller, 1997

Medications that prevent stroke

“Blood thinners”Antiplatelet Agents

•Aspirin

•Aspirin/extended release dipyridamole (Aggrenox)

•Clopidogril (Plavix)

•Ticlopidine (Ticlid)

Anticoagulants

•Coumadin (warfarin)

•Exanta

•Heparins

Aspirin for prevention of stroke

•Aspirin benefit independent of dose and gender

•FDA, AHA & ACCP all recommend– an aspirin dose between 50 and 325 mg/day

Albers GW at al Neurology 1999;53(suppl. 4):S25-S38 FDA. Federal Register. 1998;63:56802.Albers GW, et al. Chest 2001, 119: 300S-320S.

Choice of medication for stroke prevention

What is the cause of the stroke?

Atherosclerosis Unknown Heart

Warfarin

(Coumadin)

Antiplatelet therapy

Albers GW, et al. Chest 1998;114:683S-698SBarnett HJ et al. N Engl J Med. 1998;339:1415-1425

Prevention of recurrent stroke Stroke caused by atrial fibrillation

EAFT Study Group Lancet 1993, 342: 1255-62

66%

15%

80%

60%

40%

20%

0%

Benefit of warfarin

Benefit of aspirin

Relative Risk Reduction

How to prevent a stroke

• Control treatable risk factors

• Take an anti-platelet agent or an anti-coagulant

• Surgical therapy for carotid stenosis

Changing the perception of stroke

MYTH

• Stroke is unpreventable

• Cannot be treated

• Strikes only the elderly

• Recovery ends 6 months after a stroke

REALITY

• Stroke is largely preventable

• Requires urgent treatment

• Can happen to anyone

• Stroke recovery can continue throughout life

Stroke Websites

American Stroke Association:www.strokeassociation.org

National Stroke Association:www.stroke.org

Stanford Stroke Centerwww.stanford.edu/group/neurology/stroke/