CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 3, April 2013
AFRICA
91
Treatment of large-artery atherosclerosis
Carotid revascularisation by carotid endarterectomy (CEA)
or carotid angioplasty and stenosis (CAS) has been well
documented in research to prevent strokes, provided there is
appropriate case selection with the risk–benefit ratio being
favourable for the patient. Current AHA guidelines advocate
CEA for severe ipsilateral carotid artery stenosis (70–99%)
in patients with recent TIA or ischaemic strokes, if the peri-
operative morbidity and mortality risk is less than 6%.
50
CEA
can be considered for moderate carotid stenosis (50–69%)
depending on patient-specific factors such as age, gender and
co-morbidities and again, if the peri-operative morbidity and
mortality risk is less than 6%.
With stenosis less than 50%, CEAor CAS is not recommended.
When the diameter of the lumen of the internal carotid artery is
reduced by 70% on non-invasive imaging or 50% on catheter
angiography, CAS can be considered as an alternative to CEA
for symptomatic patients at average or low risk of complications
associated with endovascular intervention.
Conclusion
There are many different ways of treating AIS. However the
evidence points to IV r-tPA as the most effective and at present
the gold standard of AIS treatment. Despite this, recanalisation
treatments as described are flourishing at a rapid rate and more
emphasis and interest are being directed at these areas. Although
vessel recanalisation is vital to increasing the possibility of
significant tissue reperfusion, clinical trials need to emphasise
functional outcomes rather than reperfusion/recanalisation rates
to adequately assess success of these devices/techniques.
Our view is that until these treatments become proven in
large-scale studies, a greater endeavour should be made in
resource-limited settings to expand facilities to enable IV r-tPA
treatment within the 4.5-hour period following onset of the
stroke. The resources required are small with the main costs
being a CT scan of the brain and the cost of r-tPA. This can easily
be done in any emergency facility in any part of the world.
What is needed is public awareness, and campaigns of ‘stroke
attack’ should be revisited, especially in the resource-limited
context. Intensive public-awareness campaigns (television,
radio, the internet, social networking, newspapers) about early
recognition of stroke as well as the importance of time constraints
for a favourable outcome should be devised.
Education of emergency medical personnel as well as staff
of smaller medical facilities is also crucial in enabling faster
referral to a unit where thrombolysis can be done. This approach
at present will halt to some extent the stroke pandemic that
we are facing. Public profiling of stroke will strongly assist in
dealing with risk factors and implementation of preventative
strategies.
A final point that needs to be made is that imaging modalities
are being refined towards identifying with more accuracy patients
who would fulfill the criteria for IV thrombolysis following
ischaemic stroke. Currently multi-parametric MRI studies are
gaining momentum in terms of identifying such patients.
Specifically, diffusion–perfusion mismatch, gradient echo,
MRA (MR angiogram) and FLAIR (Fluid Attenuated Inversion
Recovery) sequences on MRI are being used. These have
the advantage of providing more detailed information of the
ischaemic penumbra and the extent of infarction that cannot
be determined on CT scanning techniques. This reduces the
risks of intracranial haemorrhage following thrombolysis. The
disadvantage is that patients who would have otherwise qualified
by CT criteria are likely to be rejected on the MRI criteria.
Further refinements in this area are likely to occur that will make
thrombolysis more objective with better outcomes.
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