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

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Presentation on theme: "BLOOD PRESSURE MANAGEMENT IN ACUTE STROKE Pat Melanson, MD McGill University."— Presentation transcript:

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

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

4 Stroke Protocols Aspiration pneumonia, UTI’s DVT prophylaxis Glucose control Fever control BP management –avoidance of overtreatment

5 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?

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

7 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

8 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

9 50 150 Cerebral Autoregulation CBF 50 ml/100g/min MAP 20

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

11 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)

12 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 %

13 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

14 Pharmacologic Therapy

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

16 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

17 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

18 Recommended Antihypertensives Beta-blockers Alpha-blockers ACE inhibitors Clonidine

19 Labetalol Combined ,  adrenergic blockade Usual contraindications to  - 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

20 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

21 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

22 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

23 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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