Academic Day Seminars

ADS – Stroke

Image result for stroke

This was a great lecture done by our co-residents, Anna and Julie!

Some clinical pearls I picked up:

Stroke types:

  • Ischemic stroke:
    • Blood flow to brain is compromised due to:
      • Atherosclerosis of cerebral vessels
      • Embolus to cerebral arteries from distant clot
  • Hemorrhagic stroke:
    • Escape of blood from blood vessels into the brain and surrounding structures
    • Results in direct irritant effects of blood that is in direct contact with brain tissue
    • Causes include cerebral artery aneurysm, arteriovenous malformation, hypertensive hemorrhage, and trauma

Drugs that can mimic stroke: lithium, phenytoin, carbamazepine (should do levels to assess if toxicity is occurring)

Lab tests to do when assessing stroke:

  • CBC, platelets, INR, PTT, electrolytes, random glucose, SCr, eGFR, BUN, troponin
  • In select pts: blood or urine screen, preg test
  • Additional lab tests: fasting lipid profile, HbA1C, fasting glucose, ALT, AST, GGT, ALP, albumin
  • Immunological tests (to R/O vasculitis as a screen): ESR, CRP, ANA, C, p-ANCA, C3/C4, ENA
  • Coagulopathy (to assess if patient is at risk of thrombogenesis): antiphospholipid antibody, lupus anticoagulant, sickle cell screen, anti-beta2-glycoprotein type 1

Management of acute stroke:

  • Hyperacute (<6 hours): O2, BP, glucose, temp, volume status, reperfusion
    • BP treat to a target below 180/105 mmHg
    • Ischemic stroke patients not eligible for thrombolytic therapy
      • Only tx extreme BP elevation (SBP > 220 mmHg or DBP >120 mmHg)
    • Goal is to reduce BP by ~15%, but not more than 25% over the first 24 hours.
    • Should we let BP ride high?
      • Advantages: could improve cerebral perfusion of ischemic tissue
      • Disadvantages: could exacerbate edema and hemorrhagic transformation of ischemic tissue, encephalopathy, cardiac complications, renal insufficiency
    • Fibrinolysis: goal is door to needle time <60 mins for tPA
      • Blood glucose is the only lab test that must precede tPA administration
  • Acute (>24 hours): antiplatelet, VTE prophylaxis

Antiplatelet therapy in acute stroke: Acute aspirin therapy reduces risk of early recurrent ischemic stroke.Canadian best practice recommendations 2015:

  • All acute stroke patients not already on an antiplatelet, and not receiving tPA:
    • 160mg of ASA immediately after imaging excludes ICH and dysphagia screening performed
  • In patients treated with tPA: Delay ASA until after 24h post-thrombolysis scan has excluded ICH
  • In all patients: continue ASA 81 to 325 mg daily indefinitely, or until alternative anti-thrombotic started
  • Clopidogrel may be considered in patients on ASA prior to stroke or TIA as an alternative
  • In dysphagic patients ASA may be given by enteral tube (80mg daily) or 325 mg pr daily

Secondary stroke prevention:

  1. Lifestyle management: healthy balanced diet (e.g. Mediterranean diet), sodium intake <2g/day, exercise, weight (BMI 18.5-24.9kg/m2 or waist circumference <88 cm (women), <102 cm (men)), avoid alcohol, OC &HRT should be D/C’d, smoking cessation, refer for sleep apnea
  2. Blood pressure
    • Hypertension – single most important modifiable risk factor for stroke
    • HOPE: Ramipril (NSS reduction in stroke in 2ry prevention)
    • PROGRESS: Perindopril + Indapamide reduced stroke risk in combo
    • PRoFESS: Telmisartan (NSS reduction in 2ry prevention)
    • SPS3: SBP target 130-149mmHg or SBP <130 mmHg showed no benefit in reduction of risk of all stroke, disabling or fatal stroke, major vascular events.
  3. Antiplatelet therapy
    • All pts w/ ischemic stroke or TIA should be prescribed antiplatelet therapy for 2ry prevention of recurrent stroke unless there is an indication for anticoagulation
      • ASA (80-325mg), ASA/dipyridamole (25/200mg), clopidogrel (75 mg)
    • The combo of ASA and clopidogrel is stil of uncertain benefit for ealry prevention of recurrent stroke when used within 90 days and should not be routinely used in all pts, short term combo use has not been showed to cause an increased risk of bleeding
  4. Statins
    • Statin should be prescribed with a target LDL of <2 mmol/L or a 50% reduction in LDL from baseline
    • SPARCL: atorva 80mg daily if LDL > 2.6 mmol/L
      • Recurrent stroke HR 0.84 (NNT = 53 x 5 years), fatal stroke HR 0.57 (NNT =143), hemorrhagic stroke HR 1.66 (NNH = 107 – no excess fatal hemorrhagic stroke)
    • HPS: simva 40mg daily
      • 27% RRR for stroke, 1.6% ARR, NNT = 63 x 5.5 years
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