Download three principal strategies for secondary prevention

secondary prevention after a TIA
or ischemic stroke
• stroke ; second most common cause of death
after myocardial infarction
• a leading cause of acquired disability.
• Patients with stroke are at high risk for
subsequent vascular events, including
recurrent stroke (highest risk), myocardial
infarction, and death from vascular causes.
• at least 80% of recurrent events might be
prevented with ;
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1- life style
2-blood-pressure lowering,
3- antiplatelet therapy, and
4-statin therapy.
TIA definition
• TIAs were traditionally defined as brief
neurologic episodes of vascular origin lasting
less than 24 hours.
• More recently, TIAs have been classified as
transient neurologic events without signs of
acute infarction on imaging.
classification for ischemic stroke
1- cardioembolism (most commonly from atrial
fibrillation)
2- large-artery disease
3- small-vessel occlusion (lacunar stroke),
4- stroke of other cause (e.g., arterial dissection,
drug-related stroke, or a hypercoagulable
disorder)
5- Cryptogenic stroke up to 30%
three principal strategies for secondary
prevention,
1- Blood pressure
2- lowering, cholesterol lowering with statins
3- antiplatelet therapy (except in patients in
whom anticoagulant therapy is indicated).
Antiplatelet Therapy
4 main Antiplatelet ;
• Aspirin
• clopidogrel
• Ticlopidine
• dipyridamole
Antiplatelet Therapy
Early phase (90days>)
vs
late phase (90<)
Early phase
• Early phase of stroke associated with higher
risk of stroke recurrence than late.
• Short-term use of the combination of aspirin
and clopidogrel in early phase
• the rate of stroke recurrence at 90 days ;
10.8% in aspirin versus 7.1% in combined
aspirin and clopidogrel.
Late phase;
• Aspirin; a meta analysis of trials suggested
that aspirin reduced the risk of subsequent
vascular events by only 13%;
• Low doses of aspirin (ranging from 75 to 325
mg per day) appear to be as effective as
higher doses in reducing the risk of stroke
• clopidogrel were shown in randomized trials
to be superior to aspirin, but the absolute
benefits were very small.
• For patients intolerant to aspirin because of
allergy or gastrointestinal side effects,
clopidogrel is an appropriate choice.
Combination therapy
• the combination of aspirin plus dipyridamole
were shown in randomized trials to be
superior to aspirin without increasing risk of
hemorrhage, but the absolute benefits were
very small.
Combination therapy
• clopidogrel + aspirin ; Randomized trials have
shown no benefit, and increased hemorrhagic
risks, with the combined use of clopidogrel
and aspirin as compared with clopidogrel
alone or aspirin alone for long-term secondary
prevention after stroke.
Recommendation
• Current guidelines indicate that aspirin alone,
clopidogrel, or aspirin plus dipyridamole are
all acceptable first line options in secondary
stroke prevention.
Blood-Pressure Lowering
• Blood pressure is the most important
modifiable risk factor in both primary and
secondary prevention of stroke.
• Meta-analyses of randomized controlled trials
confirm an approximate 30% to 40% stroke
risk reduction with BP lowering.
• benefits have been linked to absolute bloodpressure reductions of approximately 10/5
mm Hg
• Whether the benefits of blood-pressure
lowering depend on the particular class of
antihypertensive drugs or simply on the
antihypertensive effect of all such drugs
remains controversial, although most of the
evidence appears to support the latter.
Cholesterol Lowering with Statins
• effective in primary and secondary stroke
prevention
• Secondary- prevention guidelines recommend
1- start; if LDL cholesterol level of >=100
• 2- aim; the level by at least 50% or achieving a
=<70.
Carotid Endarterectomy and CarotidArtery Stenting
• Carotid endarterectomy is indicated for the
treatment of patients with a history of TIA or
nondisabling ischemic stroke who have highgrade (70 to 99%) carotid stenosis or, in
selected cases, moderate (50 to 69%) stenosis
• no benefit in those with mild (<50%) stenosis
timing of carotid endarterectomy
• after a TIA or ischemic stroke involves
balancing the risk of early recurrent events
with the risk of reperfusion injury and
hemorrhagic transformation.
• Early intervention, within 2 weeks after the
onset of symptoms, is now recommended,
given evidence that the benefits of surgery
rapidly diminish with increasing time since the
ischemic event
carotid-artery stenting
• The use of carotid-artery stenting as an
alternative to carotid endarterectomy is more
controversial. Carotid-artery stenting is less
invasive than endarterectomy and is
associated with a more rapid recovery .
However, studies have shown that the
periprocedural risks (chiefly death and
recurrent stroke within 30 days) are
significantly higher with carotid-artery
stenting than with carotid endarterectomy
• Among patients with symptomatic severe
stenosis (>70%) in whom the stenosis is
difficult to access surgically, medical
conditions with increase the risk of surgery,
radiation-induced stenosis or restenosis after
CEA, CAS is not inferior to endarterectomy and
may be considered.
Cardiogenic embolism
• Cardiogenic cerebral embolism derived from a diversity
of cardiac disorders is responsible for '20% of ischemic
strokes.
• Transesophageal echocardiography is an appropriate
method to investigate people younger than 45 years of
age with suspected cardiogenic emboli, and older
people without signs of cardiac disease like AF and CHF.
• Transthoracic echocardiography generally is adequate
when clinical evidence of cardiac disease is present.
• Twenty-four-hour continuous (Holter) ECG monitoring
for detection of paroxysmal atrial fibrillation
• cardiac conditions with high embolic potential
include acute MI, infective endocarditis,
rheumatic mitral stenosis, mechanical prosthetic
heart valves, dilate cardiomyopathy, and cardiac
tumors
• Low or uncertain embolic risk disorders include
aortic valve calcification, calcific aortic stenosis,
remote MI, left ventricular aneurysm,
hypertrophic cardiomyopathy, patent foramen
ovale (PFO), atrial septal aneurysm (ASA), atrial
flutter
Anticoagulation & AF
• Warfarin has also been shown to be more
effective than aspirin or the combination of
aspirin plus clopidogrel for secondary prevention
of stroke in patients with atrial fibrillation.
• For patients with ischemic stroke or TIA with
persistent or paroxysmal (intermittent) AF,
anticoagulation with adjusted-dose warfarin
(target INR, 2.5; range, 2.0 to 3.0) is
recommended
• For patients unable to take oral anticoagulants,
aspirin 325 mg/d is recommended
Anticoagulation & Acute MI and Left
Ventricular Thrombus
• For patients with an ischemic stroke or TIA
caused by an acute MI with LV mural
thrombus, oral anticoagulation is reasonable,
aiming for an INR of 2.0 to 3.0 for at least 3
months and up to 1 year
• Aspirin should be used concurrently for
ischemic coronary artery disease during oral
anticoagulant therapy in doses up to 162
mg/d
Prosthetic heart valves
• For patients with ischemic stroke or TIA who have
modern mechanical prosthetic heart valves, oral
anticoagulants are recommended, with an INR
target of 3.0 (range, 2.5–3.5).
• For patients with mechanical prosthetic heart
valves who have an ischemic stroke or systemic
embolism despite adequate therapy with oral
anticoagulants, aspirin 75 to 100 mg/d, in
addition to oral anticoagulants, and maintenance
of the INR at a target of 3.0 (range, 2.5–3.5) is
reasonable.
Newer Anticoagulation
• dabigatran ,Rivaroxaban, Apixaban
• Do not require monitoring
• dabigatran (a direct thrombin inhibitor); at a dose
of 150 mg twice per day, was superior to warfarin
in the prevention of stroke or systemic embolism,
with a similar risk of overall major bleeding but a
significantly lower risk of intracranial
hemorrhage.
• At a lower dose (110 mg twice per day),
dabigatran was noninferior to warfarin, with a
lower risk of overall major bleeding.
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