Epidemiology, Mechanisms & Clinical Description of...
Transcript of Epidemiology, Mechanisms & Clinical Description of...
Epidemiology, Mechanisms & Clinical Description of Stroke
Michael R. Jaff, DO, FACP, FACCDirector, Vascular Medicine
Massachusetts General HospitalBoston, Massachusetts
Michael R. Jaff, DOConflicts of InterestMichael R. Jaff, DOConflicts of Interest
ConsultantCordis Endovascular (Modest)Boston Scientific (Modest)Medtronic Vascular (Modest)Pathway Medical (Modest)Paragon IP (Modest)X-Tent, Inc (Modest)Harvard Clinical Research Institute (Modest)Bacchus Vascular, Inc (Modest)Baxter, Incorporated (Modest)ActivBiotics (Modest)
EquityAccess Closure, Inc (Modest)Square One, Inc (Modest)Vascular Therapies, Inc (Modest)Icon Interventional, Inc (Modest)Setagon (Modest)I.C.Sciences, Incorporated (Modest)
Speaker’s BureauBristol-Myers/Sanofi-Aventis Pharmaceuticals Partnership (Modest)
Research SupportPfizer, Inc.Abbott VascularGenzyme
June, 2007
Rate of Deaths Due to Atherosclerosis is Increasing in U.S.
JAMA 2005;294:1255.
The Worldwide Stroke Pandemic
695,000
348,000
685,000316,000
468,000604,000
554,000
1,647,000
887,000
700,000
Burden of Stroke in the U.S.
1 stroke every 45 seconds (700,000 per year)2.4 million non-institutionalized stroke survivorsStroke causes 1 in 15 deathsApproximately 30 % aged 70-80 have silent brain infarction Stroke cost= 58.8 billion/year
Prevalence of Survivors of Various Disabling Neurologic Conditions
0 0.5 1 1.5 2 2.5 3 3.5
Stroke
Epilepsy
Alzheimer's
Parkinson's
What is a Stroke?
Reduction in arterial blood flow to the brain, resulting in ischemia to the brain itselfThe brain has geographic territories responsible for our higher functions
Transient Ischemic Attack (TIA)
15% of all strokes are heralded by a TIA. 1/3 of TIAs would be infarction based on diffusion weighted MRI findings. Males and blacks have higher rates of TIA.Half fail to report TIA to their healthcare providers. 90-day risk of stroke is 3-17% after TIA, highest within the first 30 days.Carotid-associated TIA: 20% 90-day stroke risk
Carotid Artery Disease: TIA
Duration <24 h, usually <15 minSymptoms:
motor and sensory dysfunction of contralateral limbspure sensory dysfunctionisolated dysphasiatransient monocular blindness
TIAs Cause Early Stroke and Cardiovascular Events
Follow up of 1707 subjects diagnosed with TIA in ED
Risk Factors for Events:OR
Age > 60 y 1.8Diabetes 2.0>10 Min TIA 2.3Weakness 1.9Speech 1.5
JAMA. 2000;284:2901-2906
Territories of the Middle Cerebral Artery
The Vascular Supply to the Brain is Rich, But Vulnerable!
Intracranial Anatomy
Vascular Territories and Stroke Syndromes
What Are the Common Causes of Stroke?
Ischemic (80%)ThrombosisEmbolism
Hemorrhagic (20%)IntracerebralSubarachnoid
Stroke Subtype Frequency
Furie KL, Kistler JP, NEJM 2000
Frequency of Stroke Types
Artery to Artery Embolism
Does Risk of Stroke Increase with Greater Degrees of ICA Stenosis?
696 Patients evaluated with Carotid Duplex Ultrasonography369 Male/327 Female
Mean Age 64 yearsMean Follow-Up 41 monthsDuplex Ultrasonography Categories
Mild <50% StenosisModerate 50-75% StenosisSevere >75% Stenosis
Stroke 1991;22:1485
Vascular Risk of Asymptomatic Carotid Stenosis
Category N TIA CVA CardiacEvent
VascularDeath
<50% 303 1 1.3 2.7 1.8
50-75% 216 3 1.3 6.6 3.3
>75% 177 7.2 3.3 8.3 6.5
75% of Events were Ipsilateral to the StenosisStroke 1991;22:1485
What Can the Physical Exam Tell You About the Etiology of Stroke?
Atrial Fib/Flutter, Bradycardia Likely Cardiogenic EmbolusNo pulse below knee Recurrent systemic embolusCarotid Bruit Severe Extracranial Carotid
StenosisHead/Orbital Bruit AV MalformationFever and Acute CVA Endocarditis and Cardiogenic
EmbolusStroke and Altered MS Check Glucose, EtOH,
Narcotics, O/D, other Toxins
Cervical Bruit
Marker of systemic atherosclerosisNot indicative of severity of internal carotid artery stenosis
NASCET: Sensitivity 63%/Specificity 61%Frequency of Cervical Bruits
~1-3% in adults aged 45-54 years~8% in adults >75 years
Bruit and Carotid Artery Disease
Presence of Bruit Increases Likelihood of Carotid Disease
020406080
100
StrokewithBruit
TIA withBruit
Bruit Control
35-75% Stenosis >75% Stenosis
Zhu, CZ. Stroke 1990;21:1131-1134
Carotid ultrasound evaluation in 261 pts with ischemic CVA, 813 pts with carotid TIAs, 500 pts with asymptomatic neck bruits, and 500 controls.
Causes of Cervical Bruit (Systolic, Diastolic, or Both)
Carotid atherosclerosisThyrotoxicosisTransmitted cardiac murmur
Aortic Stenosis (systolic)Aortic Insufficiency (diastolic)
Arteriovenous Fistula (systolic/diastolic)Venous Hum (systolic or systolic/diastolic)
Once in an ED, You Must Get an Imaging Test IMMEDIATELY!
Classic Wedge-Shaped Acute Right MCA Stroke
Important Characteristics of the CT Scan
Within 3 hours of onset of ischemia, the CT without contrast is virtually normalAfter 6-12 hours, there is evidence of hypodensity with brain edemaHemorrhage
Appearance will describe type– Subdural Hematoma: Crescent shape below dura– Subarachnoid Hemorrhage: Diffuse blood pattern along
surface of brain in subarachnoid space5% of SAH have NORMAL CT!!! MUST perform Lumbar PunctureDiscern between SAH and traumatic LPRBC Count in 4 tubes all similarXanthochromic Supernatant---old RBCs consistent with SAH
MRI Demonstrating Acute Right MCA CVA
National Institutes of Health Stroke Scale (NIHSS)
Systematic clinical assessment tool Designed in 1983 to standardize and document a reliable, valid neuro assessmentMeasures neurologic deficits
Does not assess function5-8 minutes to completeScores range from 0-42 11 items tested
http://www.ninds.nih.gov/doctors/stroke_scale_training.htm
What if Patient Has Altered Mental Status?
Glasgow Coma Scale
Eye OpeningSpontaneous…4In response to speech…3In response to pain…2None…1
Best Verbal ResponseOriented…5Confused…4Inappropriate Words…3Incomprehensible…2None…1
Best Motor ResponseObeys…6Localizes…5Withdraws…4Abnormal Flexion…3Abnormal Extension…2None…1
Glascow Coma Scale
Stroke Prevention Strategies
Reduction in Blood PressureCessation of Tobacco UseReduction in Serum CholesterolAggressive Glycemic ControlAntiplatelet TherapyRevascularization of Carotid Stenosis