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BLOOD PRESSURE MANAGEMENT IN ACUTE STROKE

BLOOD PRESSURE MANAGEMENT IN ACUTE STROKE. Pat Melanson, MD McGill University. “Brain Attack”. Paradigm shift - End of nihilism Early effective interventions Time-sensitive disease Chain of recovery Stroke units and stroke centers. Stroke Protocols. Aspiration pneumonia, UTI’s

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BLOOD PRESSURE MANAGEMENT IN ACUTE STROKE

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  1. BLOOD PRESSURE MANAGEMENT IN ACUTE STROKE Pat Melanson, MD McGill University

  2. “Brain Attack” • Paradigm shift - End of nihilism • Early effective interventions • Time-sensitive disease • Chain of recovery • Stroke units and stroke centers

  3. Stroke Protocols • Aspiration pneumonia, UTI’s • DVT prophylaxis • Glucose control • Fever control • BP management • avoidance of overtreatment

  4. Cases • Ischemic CVA, BP 225/105 (145) • Hemorrhagic CVA, BP 215 /110 (145) • Would you actively lower the BP? • What target or threshold level? • What drug ? • Which drugs should be avoided?

  5. Lowering BP in Acute Stroke: Pros • Chronic hypertension • Rebleed/ increase hematoma size • Cerebral edema, Raised ICP • Hemorrhagic transformation • Decrease bleeding with t-PA

  6. Lowering BP in Acute Stroke: Cons • Acute hypertension is self-limited • RISK OF ISCHEMIA • Reflex response to maintain CBF • Ischemic penumbra • Shift in autoregulation curve • More sensitive to BP decreases

  7. Cerebral Blood Flow • CBF = CPP / CVR • CPP = MAP - ICP • MAP = DBP + 1/3 PP • Cerebral autoregulation • normal between 50 - 150 • 70/40 to 200/130

  8. Cerebral Autoregulation CBF 50 ml/100g/min 20 150 50 MAP

  9. Cerebral Autoregulation • MAP below lower limit • hypoperfusion with ischemia • MAP above upper limit • “breakthrough” vasodilation • Segmental pseudospasm (“sausage-string”) • fluid extravasation

  10. Cerebral Autoregulation • Shift to right • Chronic hypertensives • ICH, SAH, Ischemic infarct • Trauma • Cerebral edema • Age, atherosclerosis • Some hypertensives suffer decrease CBF at MAP higher than 120 (160/100)

  11. How far can BP be safely lowered? • Lower limit usually 25% below MAP • 50% of chronic hypertensives reached lower autoregulation limit with 11 to 20% reduction in MAP • 50% had lower limit above usual mean • Kanaeko et al; J Cereb Blood Flow Metab 3:S51,1983 • Most ischemic complications develop with reductions greater than 20 - 30 %

  12. Initial Lowering of BP : Therapeutic Guidelines • Do not lower BP more than 15 % over the first 1 to 2 hours unless necessary to protect other organs • Decreasing to DBP of 110 or patients “normal” levels may not be safe • Further reductions should be very gradual ( days) • Follow neuro status closely

  13. Pharmacologic Therapy

  14. Direct-acting cerebral vasodilators adversely affect CBF potential to increase ICP shift autoregulation curve to the right Nitroglycerine Nitroprusside Hydralazine Calcium Channel Blockers Drugs Best Avoided

  15. Nifedipine • Peripheral, cerebral and coronary arteriolar vasodilation • Rapid onset of antihypertensive effect • 5-20 minute onset • peak effect in 30-60 min • duration 4-5 hr • Potential severe hypotension • Several case reports of cerebral or myocardial ischemia after rapid decrease

  16. Sublingual Nifedipine • “Should a Moratorium be Placed on Sublingual Nifedipine capsules given for hypertensive emergencies and pseudoemergencies?” • Grossman, Messerli, Grodzicki, Kowey • JAMA, 276 : 1328 - 1331,1996

  17. Recommended Antihypertensives • Beta-blockers • Alpha-blockers • ACE inhibitors • Clonidine

  18. Labetalol • Combined a, b adrenergic blockade • Usual contraindications to b-blockade • Rapidly effective when given IV; • Onset < 5 min, peak 5-10 min, duration 2-6 hr (sometimes longer) • 5 - 10 mg iv q10 minutes

  19. ACE inhibitors • IV enalaprilat, oral captopril potentially useful for acute BP reduction • Difficult to titrate (sometimes ineffective,sometimes excessive BP ¯) • Positive effects on cerebral autoreg. • Captopril 12.5 mg S/L

  20. Recommendations • MAP of 140 - 145 (220/120) • Max decrease of 15 % MAP • Avoid direct acting vasodilators • Avoid sublingual nifedipine • Labetalol, Captopril • Cautious reduction with frequent neurologic exams

  21. Pharmacological Elevation of BP in Acute Stroke • Pharmacological elevation of blood pressure in acute stroke: Clinical effects and safety. Rordorf, Stroke 1997; 28:2133 • Retrospective review of 63 patients • Ischemic stroke with normal BP • 30 received phenylephrine (alpha-agonist) • 10 demonstrated a BP threshold • Improved outcome

  22. Recommendations • MAP of 140 - 145 ( 220/120) • Avoid direct acting vasodilators • Avoid sublingual nifedipine • Alpha or beta blockers, ACEI • Cautious reduction with frequent neurologic exams

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