Download Module 3 chapter 1c - The Association of Physicians of India

MODULE 3 CHAPTER 2D
HYPERTENSION AND CVA
The plan
• Introduction
• Primary prevention of stroke
• Management of hypertension during acute
stoke
• Secondary prevention
• Conclusions
Hypertension
The leading CVD risk Factor
• Contributes to 13% global
1
deaths
Hypertension
related deaths
13%
An increase in the number
and severity of risk factors
by middle age can affect a
person’s remaining lifetime
2
risk for CVD
Prevention and control of
2
CVD risk factors are crucial
http://www.world-heart-federation.org/press/fact-sheets/cardiovascular-disease-risk-factors/
viewed on May 16, 2013, http://hp2010.nhlbihin.net/joinhin/news/professional/hdrisk.asp
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Hypertension
The Indian Scenario
•
•
•
•
1
> 140 million people have high BP
1
By 2030, it is expected to cross the 214 million
Causes more strokes than ACS (34.6% vs 17.9%)
2
In India, Hypertension is responsible for
– 57% of all stroke deaths
Stroke has higher
morbidity, mortality
– 24% of all CHD deaths
So in hypertension management we must
aim at preventing strokes
and less treatment
options and success
when compared to CAD
1. http://www.thehindu.com/sci-tech/health/hypertension-major-contributor-to-avoidable-deathsin-india-who/article4513904.ece, 2. Journal of Human Hypertension (2004) 18, 73–78
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The plan
• Introduction
• Primary prevention of stroke
• Management of hypertension during acute
stoke
• Secondary prevention
• Conclusions
Commonly we see..
• Pts. with good BP control suddenly develop
CVA
• Pts. with long standing high BP don’t develop
any vascular event
12
Mean blood pressure
• The average of several readings of systolic or
diastolic pressure (expressed as numbers)
• Different from mean arterial BP (DBP+1/3 PP)
• Derived from many clinical visits, Home BP
recordings and ABPM
• 7 to 10 or more BP recordings at different clinical
visits are needed to get mean blood pressure
• Mean BP , thus obtained may be an accurate
estimate of usual blood pressure
13
BP variability
• The variation of BP with time
• Expressed as Standard Deviation (SD)
• Variation may be for beat to beat (ultra short),
over 24hrs (Short term) or visit to visit (long
term)
• Extent of variability is positively related to
mean blood pressure
15
TO PREVENT STROKE
• Both mean BP as well as BP variability should
be addressed
• BP variability is assuming lot of importance in
the prevention of stroke
• Control of mean BP without achieving
reduction in BP variability may not yield
benefits
Examples
2 patients,5 visits
• Patient 1 :
120/130/120/130/120
Mean BP- 620/5 = 124
SD= 5.5
• Patient 2:
150/110/130/140/90
Mean BP – 620/5 =124
SD=24.08
The patient 2 has BP variability although
both patients have same mean BP
SD :Standard Deviation
17
BP variability causes and consequences
18
BP Variability
Evidences for increased risks
BP Variability
Effect seen
Ohasama prospective
study
Greater-than-anticipated
day-to-day variation in
home SBP & DBP
Increased 12-year CV and
stroke mortality risks
7.8-year follow-up of a
representative Finnish
population
Variability of self
measured home BP
during 7 consecutive days
Independent predictor of
subsequent CV events
Women’s Health Initiative Greater visit-to-visit BP
study of 58,228
variability
postmenopausal women
Canadian Journal of Cardiology 29 (2013) 557e563
Increased risk for both
ischemic and
hemorrhagic stroke
19
Which drug reduces BP variability
20
Visit to visit BPV
Stroke risk and coronary risk expressed by docile of
within-visit SBP variability
Number of patients in each
docile of within-visit SD SBP
Stroke risk
(HR, 95% CI)
Coronary risk
(HR, 95% CI)
ALLHAT TRIAL
MAP BPV
MAP: MEAN BP
MAP BPV
MAP BPV
BPV: BP VARIABILITY
REDUCTION OF STROKE WAS THE HIGHEST FOR AMLODIPINE
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For primary prevention
• The most important aspect of primary
prevention of stroke is BP control
• Calcium antagonists especially long acting
DHPs are powerful drugs to get BP targets
• They have additional benefit of reducing BP
variability which is emerging as an important
risk factor for stroke
• Even in combination therapy Calcium
antagonists should be tried in 2nd or 3rd step
The plan
• Introduction
• Primary prevention of stroke
• Management of hypertension during acute
stoke
• Secondary prevention
• Conclusions
Early recognition, transport, evaluation
and management
BP AND ACUTE STROKE
• The risk of high blood pressure in stroke is Ushaped blood pressure during acute stroke
should be neither too low nor too high, either
in ischemic or in hemorrhagic stroke
• However, the treatment of hypertension
during acute stroke remains controversial.
Auto regulation
When the pressure falls cerebral blood flow (CBF) increases due to fall in resistance.
In ischemic stroke when there is fall in CBF due to occluded artery, CBF has to be maintained
By increase in pressure (BP).
But may increase cerebral edema
THE NEW DATA
• In spite of the controversy, the evidence that blood
pressure in acute stroke should be treated when it is
very high, must be treated in some cases, and can
be treated safely, is mounting.
• The change that has made the greatest difference is
the advent of intravenous thrombolytics for acute
stroke;
• Lowering blood pressure in patients with acute
stroke eligible for tissue plasminogen activator to
achieve blood pressure below 185 mm Hg systolic
and below 110 mm Hg diastolic so that tissue
plasminogen activator can be given has become
standard therapy
Avoid BP >180/110
ICH
Patients who don’t receive tPA
• At this time, the previous recommendation not
to lower the blood pressure during the initial 24
hours of acute ischemic stroke unless the blood
pressure is >220/120 mm Hg or there is a
concomitant specific medical condition that
would benefit from blood pressure lowering
remains reasonable.
Exceptions
• Some conditions, such as myocardial ischemia, aortic
dissection, and heart failure, may accompany acute
ischemic stroke and may be exacerbated by arterial
hypertension.
• When blood pressure management is indicated for a
specific medical condition in the setting of concurrent
acute cerebral ischemia, an optimal approach has not
been determined.
• At present, blood pressure targets are based on best
clinical judgment.
• A reasonable estimate might be to initially lower the
systolic blood pressure by 15% and monitor for
neurological deterioration related to the pressure
lowering.
Ischemic stroke
not eligible for thrombolytic therapy
Intracranial hemorrhage
• In both intracerebral hemorrhage (ICH) and
subarachnoid hemorrhage (SAH), the
approach to blood pressure management
must take into account the potential benefits
(eg, reducing further bleeding) and risks (eg,
reducing cerebral perfusion) of blood pressure
lowering.
The difficulty
• Reducing the blood pressure in patients with either ICH or
SAH may be beneficial by minimizing further bleeding and
continued vascular damage .
• Patients with an intracranial hemorrhage due to ICH or
SAH may have increased intracranial pressure (ICP) due to
blood within the cranium.
• Cerebral perfusion pressure (CPP) equals MAP minus ICP.
Thus, increases in MAP may be the only means to
maintain CPP above 60 to 70 mmHg, the level necessary
to maintain perfusion .
• Measuring intracranial pressure directly allows blood
pressure to be reduced as low as possible while still
maintaining the cerebral perfusion pressure above the
conservative level of 60 mmHg
Guidelines for treatment
ICH AND SAH
• For patients with SBP >200 mmHg or MAP >150 mmHg,
consider aggressive reduction of blood pressure with
continuous intravenous infusion of medication accompanied
by frequent (every five minutes) blood pressure monitoring
• ●For patients with SBP >180 mmHg or MAP >130 mmHg and
evidence or suspicion of elevated ICP, consider monitoring ICP
and reducing blood pressure using intermittent or continuous
intravenous medication to keep cerebral perfusion pressure in
the range of 61 to 80 mmHg
• ●For patients with SBP >180 mmHg or MAP >130 mmHg
and no evidence or suspicion of elevated ICP, consider a
modest reduction of blood pressure (eg, target MAP of 110
mmHg or target blood pressure of 160/90 mmHg) using
intermittent or continuous intravenous medication, and
clinically reexamine the patient every 15 minutes
The agents- B Blockers
The agents – Sodium Nitroprusside
The agents- Calcium Antagonists
New therapy
The plan
• Introduction
• Primary prevention of stroke
• Management of hypertension during acute
stoke
• Secondary prevention
• Conclusions
Importance of BP control
• Once the stroke has stabilized,
antihypertensive therapy can reduce the rate
of recurrent stroke, independent of the
baseline blood pressure.
• Regardless of the regimen, blood pressure
reduction should be gradual.
APPROACH TO ANTIHYPERTENSIVE
THERAPY- Approach
• Which patients should be treated?
• When should therapy be initiated?
• Which antihypertensive drugs should be
used?
• What is the goal blood pressure?
Which patients should be treated?
• With few exceptions, the AHA/ASA stroke prevention
guidelines recommend initiation of antihypertensive
therapy in all patients who have had an ischemic stroke or
TIA
• However, do not recommend antihypertensive therapy in
the following settings:
• Normotensive patients who have had a stroke or TIA due
to a cardio embolic phenomenon (eg, atrial fibrillation) or
paradoxical embolus (eg, patent foramen ovale or septal
defect).
• Patients whose initial blood pressure is less
than 120/70 mmHg. These patients have an increased risk
of recurrent stroke if their blood pressure is further
reduced compared with patients who have higher blood
pressures.
When should therapy be initiated?
• After the acute management with parenteral
anti hypertensive drugs, once pt. is stabilized
and is able to take orally, appropriate anti
hypertensives should be started according to
presence or absence of compelling indications
• Dosage should be adjusted to achieve target
BP without reducing vital organ perfusion
Which antihypertensive drugs should
be used?- Monotherapy
• Based upon trial observations, both angiotensin inhibitors
(most trials have used ACE inhibitors) and calcium channel
blockers are reasonable options for initial antihypertensive
therapy in patients who have had a stroke.
• Thiazide diuretics are also commonly used, but data on
monotherapy in patients who have had a stroke are limited.
• There is some evidence from clinical trials that beta blockers
may not reduce stroke risk compared with angiotensin
inhibitors, calcium channel blockers, and, in some trials,
placebo .
• Thus, unless there is a compelling indication for their use,
beta blockers should not be used for prevention of recurrent
stroke
Which antihypertensive drugs should
be used?- Combination
The combination of an angiotensin inhibitor plus a
long-acting dihydropyridine calcium channel
blocker rather than a diuretic is preferred as the
combination antihypertensive regimen of choice in
the treatment of patients who have had a stroke.
This recommendation assumes that the patient can
tolerate and does not have a contraindication to the
use of either drug class and does not have a specific
indication for the use of another class of
antihypertensive drugs.
Goal blood pressure
• The recommendations depend upon whether
or not the event was due to a
hemodynamically significant stenosis in a
large cervicocephalic artery (ie, internal
carotid, middle cerebral, vertebral, or basilar
artery).
Goal blood pressure
• In patients with hemodynamically significant
large artery disease, it is suggested that
cautious blood pressure lowering as tolerated
but without a specific blood pressure goal
other than a minimum reduction
of 10/5 mmHg.
• However, in such patients whose initial blood
pressure is less than 120/70, do not give
antihypertensive therapy.
:
Goal blood pressure
• In patients without hemodynamically significant large
artery stenosis, the following approach is
recommended:
• Lowering the blood pressure a minimum
of 10/5 mmHg in nearly all patients
• Patients whose initial blood pressure is less
than 120/70, do not give antihypertensive therapy
• In patients with underlying hypertension, a goal
blood pressure of less than 140/90 mmHg is
recommended
• Lowering the systolic pressure below 130 to 135
mmHg can be tried if it can be achieved without
producing significant side effects.
:
Goal blood pressure
• For patients with recent small vessel (i.e.,
lacunar) ischemic stroke, lowering the systolic
blood pressure below 130 mmHg is
recommended provided it can be achieved
without side effects
The plan
• Introduction
• Primary prevention of stroke
• Management of hypertension during acute
stoke
• Secondary prevention
• Conclusions
Conclusions
• Case fatality in stroke obeys a U-shaped relationship: blood
pressures that are either too low or too high are associated
with worse outcomes both in ischemic stroke and in
intracerebral hemorrhage.
• Very high blood pressures should be lowered in acute stroke,
and there are some circumstances in which high blood
pressure must be treated despite the presence of stroke.
• To avoid worsening of ischemia by reduction in cerebral
blood flow, it is necessary to treat high blood pressure in
acute stroke with drugs that can be controlled; this usually
means giving drugs by intravenous infusion;
• However, there is recent evidence that transdermal
administration of nitrates, which can be removed if pressure
is too low, is a convenient alternative that does not reduce
cerebral blood flow in acute stroke.
Reduce BP to prevent strokes!
END OF MODULE 3 CHAPTER 2D