Hypertension with acute stroke: when to treat and when not?

BYAshraf Reda, MD,FESC

Prof and head of card. Dep., Menofiya UniversityPresident of WGLVAChairman of EGYBAC

VIII. Treatment of Hypertension in Association With StrokeAcute Stroke: Onset to 72 Hours

Treat extreme BP elevation (systolic > 220 mmHg, diastolic > 120 mmHg)

by 15-25% over the first 24 hour with gradual reduction after.

• If eligible for thrombolytic therapy treat very high BP (>185/110 mmHg)

Acute ischemic

Stroke

Avoid excessive lowering of BP which can exacerbate ischemia

Strongly consider blood pressure reduction in all patients after the acute phase of stroke or TIA .

Target BP < 140/90 mmHg

An ACEI / diuretic combination is preferred

StrokeTIA

Combinations of an ACEI with an ARB are not recommended

VIII. Treatment of Hypertension in Association With StrokeAcute Stroke: Onset to 72 Hours

Is it harmful to lower BP in acute stroke?

• Yes----No---we really don’t know• --you can easily reduce the BP in the acute

stroke and change simple hemiparesis into established hemiplegia

• Clearly, lowering blood pressure too low is harmful, but the question is, how low can you go before it is harmful?

No enough data to answer all questions

Impaired autoregulation

• Most patients have RF and already impaired auto regulation

• Reduction of bl flow to the affected areae occurs whether it is acute Hgic or ischemic stroke ---how?

• So perfusion and flow is mainly dependent on MBP

However there is always the other side of the coin

Rationale for treating HTN in AIS

• Not all patients have defective autoregulation• Penumbra (peri-infarction tissue at risk) is not

present in all cases• Clinical data suggest that many pt tolerate

gentle BP lowering• natural history studies demonstrate no

deleterious effect in the vast majority of patients when the BP falls spontaneously.

The GAIN study

Spontaneous BP fall without deleterious effects

SO……..

• high blood pressure may be deleterious in some stroke patients, particularly those receiving lytic agents

• gentle lowering of BP appears to be well tolerated in many patients

• the real issue is what is going on in that first 3 to 6 hours when the tissue is hemodynamically unstable, and that is where we need more data

Let us complicate the subject!

With a 2-mm Hg elevation in the mean pressure, you get these rather dramatic increases in MCA velocities in cerebral perfusion because it is passively dependent on blood pressure.

The main target is to resume the flow in the ischemic areas withinn3-6 hours

And the big Q is what to do with BP in this early hours

So………..

• Not all acute ischemic stroke share the same brain hemodynamics

• T-PA treated need some BP control• Without T-PA some patient need a relatively high

BP especially in the first 3-6 hours ( significant stenosis in a big artery, multiple occlusions)

• Splitting patents and tailoring therapy• Brain tissue perfusion monitoring studies are

needed

Autoregulation maintains cerebral blood flow relatively constant between 50 and 150 mm Hg mean arterial pressure.

Ruland S , and Aiyagari V Hypertension 2007;49:977-978

Copyright © American Heart Association

BP lowering agents in acute stroke

• ACEI is theoretically the best in normalising autoregulation

• Labetalol followed by Nicardipine are widely accepted and used whenever drud therapy is needed

• Nitrates could be used occasionally especially with CAD but may increase ICP

• IV enalapril• Na nitroprusside is rarely used (BP >240)• Shift to oral within 24-48 hrs

BP targets in AIS

• Previously HTN: up to180/100• Previously normotensive: 160-180/90-100

• Not t-PA illegible:– Up to 220/120 just observe except:

• Aortic dissection• Acute pulmonary edema• AMI• Hypert.encephalopathy