7 - Stroke Flashcards
What is a stroke?
abrupt onset focal neurologic deficit that lasts > 24 hours and is of presumed vascular origin
87% of strokes are ______, caused by interruption of blood flow to the brain due to a clot
ischemic
13% of strokes are _______, caused by uncontrolled bleeding in the brain
hemorrhagic
What are the 3 types of ischemic stroke?
- thrombotic
- embolic
- transiet ischemic attack (TIA)
Describe a thrombotic ischemic stroke
thrombus formation inside an artery in the brain (i.e. atherosclerosis of cerebral vasculature)
Describe an embolic stroke
emboli from intra or extra cranial arteries
Describe a carotid stenosis
Atherosclerotic plaque rupture -> thrombus formation -> local occlusion or dislodge as emboli and causes downstream cerebral vessel occlusion
Describe a cariogenic embolism
- Secondary to valvular heart disease, or non-valvular atrial fibrillation
- Atrial blood stasis -> emboli -> occlusion of cerebral circulation
What is a Transient Ischemic Attack (TIA) ?
Temporary focal neurologic deficit lasting less than 24 hrs (typically < 30 min as a result of diminished or absent blood flow)
What does a TIA commonly result from?
small clots breaking away from larger, distant clots
T or F: TIA has no residual neurologic deficit
True
Describe a hemorrhagic stroke
- Escape of blood from cerebral vasculature into surrounding brain structure
- Initial neurologic deficit attributable to direct irritant effects of blood in contact with brain tissue
What are modifiable risk factors for stroke?
- hypertension
- smoking
- dyslipidemia
- diabetes
- heart disorders (ex. atrial fibrillation, infective endocarditis)
- hypercoagulability
- lifestyle: obesity, physical inactivity, diet
- psychosocial stress (ex. depression)
- intracranial aneurysms
- alcohol use, carotid stenosis
- drugs
What are non-modifiable risk factors for stroke?
- age (risk doubles each decade older than 55 yrs)
- male sex
- family history
- prior stroke
- race
Describe the clinical presentation of a stroke
One sided weakness: sudden loss of strength or sudden numbness in the face, arm or leg
Trouble speaking: sudden difficulty speaking or understanding or sudden confusion
Vision problems: trouble seeing in one or both eyes, photophobia
Headache: sudden severe and unusual headache with no explainable cause
Dizziness: sudden loss of balance, vertigo, nausea/vomiting
Altered level of consciousness
In ACS, time = muscle.
In stroke, time = ?
brain cells
What are the warning signs of a stroke?
Face (is it drooping?)
Arms (can you raise both?)
Speech (is it slurred or jumbled?)
Time (to call 911 right away)
Acute phase of a stroke?
0-7 days
Hyperacute phase of a stroke?
0-24 hrs
Goals of therapy for Acute Phase Treatment?
- stabilization
- reperfusion
- supportive measures
- prevent complications
- prevent stroke recurrence
Describe the Acute Phase Treatment for an ischemic stroke.
ABCs
BPs
- HTN common and transient in acute phase post stroke
- Treat only if SBP > 220/120 mmHg, have evidence of aortic dissection, acute MI, pulmonary deem or hypertensive encephalopathy
- aim for moderate reduction only (15-25%)
- patients eligible to receive thrombolytic should target SBP < 185 and DBP < 110
Fluid, electrolytes, temperature
Glucose management
Neurological assessment
Early reperfusion
Describe the options for reperfusion for an ischemic stroke
Thrombolysis with r-tPA (tissue plasminogen activator) is the gold standard
or
Endovascular Therapy (EVT)
What is the inclusion criteria for Thrombolysis with r-tPA?
- age 18 and up
- ischemic stroke causing measurable neurologic deficit
- r-tPA can be given within 4.5 hours of symptom onset
What is the exclusion criteria for Thrombolysis with r-tPA?
- only minor or rapidly improving stroke symptoms
- any source of active hemorrhage or any condition that could increase risk of major hemorrhage after r-tPA
- any hemorrhage on brain imaging
- recent major surgery
- SBP>185 or DBP>110 refractory to antihypertensives
What is the dose for Thrombolysis with r-TPA?
Dose: 0.9mg/kg (max 90mg) over 1 hr, 10% IV bolus over 1 min
What do you need to avoid with r-TPA?
anticoagulants or anti platelets for 24 hours
What do you need to monitor for r-TPA?
- BP
- neurologic response
- signs of bleeding/hemorrhage
Describe EVT (endovascular therapy)
goes in femoral artery and goes all the way to cerebrovascular artery and retrieves the clot
What is the criteria for endovascular therapy (EVT)
- age > 18
- functionally disabling stroke
- infarct in a major cerebral artery
- must be done within 6 hrs of stroke onset
What is the point of taking anti platelets after an ischemic stroke?
-Reduces the risk of early recurrent stroke
What dose and when should ASA be initiated after an ischemic stroke?
ASA 160 - 325 mg PO daily within 24-48 hours after stroke onset
Describe combination anti platelets
Clopidogrel/ASA combo reduced risk of recurrent stroke without increased hemorrhagic stroke
Clop: LD = 75-300mg x 1 day 75 mg x 90 days \+ ASA: LD = 300 mg x 1 day 75mg daily x 21 days
VS.
ASA: LD = 75-300 mg x 1 day
75 mg daily x 90 days
When does combination anti platelet therapy need to be given?
within 12 hours of symptom onset
What is the bottom line for Combining Antiplatelets?
- ASA/clop combo not indicated in most cases due to concern of increased bleeding risk/hemorrhagic transformation
- combo anti platelet therapy beyond 90 day not recommended for stroke prevention due to lack of benefit in long term secondary prevention and increased bleeding risk
What type of patients are recommended to get LMWH or UFH?
For hospitalized patients with limited mobility for DVT prophylaxis
When should LMWH or UFH be administered?
within 24-48 hours (avoid within 24 hr of thrombolytic)
What is included in Acute Phase Monitoring for ischemic stroke?
1) Neurologic symptoms
- speech, extremity strength, facial symmetry
- worsening symptoms indicate recurrence or extension (i.e. presence of cerebral edema or increased intracranial pressure, or ICH)
2) Blood pressure
3) Electrolytes
4) Complications
- DVT/PE - calf/chest pain
- Infections (UTI or pneumonia symptoms, CBC, temp)
5) Adverse effects
- Signs of bleeding: Hgb, plt, INR
Describe the surgical intervention options for secondary prevention of an ischemic stroke
1) CEA - Carotid Endarterectomy:
- Indicated for carotid artery stenosis of > 70% on the side of the neurologic deficit
- Only performed in experienced stroke centre
2) CAS - Carotid Artery Angioplasty and Stenting:
- Restricted to patients refractory to medical therapy and not surgical candidates
- Higher 30-day stroke/death rate vs. CEA
What do we recommend for patients with noncardioembolic ischemic stroke or TIA?
the use of anti platelet agents rather than oral anticoagulation is recommended to reduce the risk of recurrent stroke and other cardiovascular events
Describe ASA as secondary prevention of ischemic stroke
- Most evidence and experience
- Most common AE are dose related (upper GI discomfort, bleeding)
- Least expensive
Describe using ASA + Extended Release Dipyridamole (ERDP)
- Dypyridamole no more efficacious than ASA alone
- ASA 25 mg + ERDP 200 mg BID superior to ASA alone in secondary stroke prevention
- ASA daily dose of 50mg insufficient for cardiac protection
- Most common AE = (headache, dyspepsia, nausea, diarrhea)
- Increased risk of bleeding with combination vs ASA alone
- Cost/convenience not as favourable vs. ASA alone
Describe using clopidogrel as secondary prevention for an ischemic stroke
- No difference in stroke rate when compared to ASA
- Similar risk of recurrent stroke when compared to ERDP-ASA - clopidogrel group showed less bleeding and headache
- Most common AE (diarrhea, rash)
- Less GI bleeding than ASA
-Cost
Describe using ticagrelor as secondary prevention for an ischemic stroke
-Ticagrelor (180mg load + 90mg BID) not superior over ASA (300mg + 100mg daily)
Should ASA and clopidogrel be used alone as secondary prevention for an ischemic stroke?
No benefit using them together. Just increases risk of bleeding.
Describe using warfarin as secondary prevention for an ischemic stroke
Warfarin targeting an INR of 1.4 - 2.8 not superior to ASA 325mg for prevention of recurrent events. Increased bleeding risk with warfarin
**NOT recommended for noncardioembolic ischemic stroke
What if a patient had recurrent stroke while taking ASA?
They don’t know what to do.
-No evidence to support one therapy vs another.
Were they taking ASA correctly?
-could increase dose from 81mg to 162 mg
Were they taking any other drugs that would interact with ASA?
ex. NSAIDs
Secondary Prevention for Cardioembolic stroke:
What is recommended for patients with first and recurrent stroke in non-valvular atrial fibrillation?
- Warfarin with target INR = 2.5
- Apixaban
- Dabigatran: Exceptions Clcr < 15 mL/min
- Rivaroxaban is reasonable
- For patients unable to take oral anticoagulants, ASA alone is recommended.
Describe DOACs (direct oral anticoagulants) as secondary prevention for cadioembolic stroke
- Relatively new on the market
- No measure of anticoagulation state
- No reversible agent in cases of severe, life-threatening bleed
- Not approved for patients with valvular AF
What else is key in secondary prevention?
- Blood Pressure Lowering
- Statin Therapy
- Diabetes Management
- Lifestyle Changes
- Depression Screening
Why is Blood Pressure Lowering key in secondary prevention?
- Crucial for both ischemic and hemorrhagic stroke prevention (for primary prevention as well)
- Acute stroke period: Maintain SBP 141-150 - risk of decreased cerebral blood flow and worsened symptoms if aggressive BP lowering
- Antihypertensive can be restarted 24 hr after stroke if needed
- Long term BP control: target BP < 140/90
**CHEP recommends ACEi/diuretic combination; however, selection of agent not as important as BP control
Why is Statin therapy key for secondary prevention?
Statin recommended as secondary prevention for most patients who have had an ischemic stroke or TIA; target LDL < 2.0 mmol/L, or a 50% reduction in LDL from baseline
What lifestyle changes are recommended as secondary prevention?
- smoking cessation
- avoid alcohol consumption
- increase physical activity
- weight loss
- diet less in saturated fat
