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Watershed (WS) infarction is a type of ischemic stroke
which can be defined as infarction in a region of the brain
where the distributions of nutrient arteries meet, or overlap; in
these areas, tissue perfusion is most compromised when blood
flow is decreased (Stedman’s Medical Dictionary, 2006),
watershed infarction has two types; cortical watershed (CWS)
and internal watershed (IWS) (Bogousslavsky, 1986).
The most important and specific risk factor for WSI is
hemodynamic impairment. Several factors lead to decrease
perfusion pressure such as (severe hypotension due to blood
loss, shock, heart failure…); local causes (extra cranial or
intracranial stenosis) play the major role in the pathogenesis of WSI.
Intracranial stenosis is a narrowing of the arteries inside the brain
similar to carotid stenosis in the neck (Ringer et al., 2005).
Aim of the work
1. To identify the prevalence of watershed infarction among all
types of acute ischemic stroke.
2. To assess the relationship between watershed infarction and
intracranial stenosis.Subjects and Methods
One hundred and seventeen Egyptian patients were
recruited into this hospital-based case-control study. Clinical
history, laboratory indices, structural brain imaging, Magnetic
Resonance Angiography (MRA) and Carotid Duplex
ultrasonography were done for all patients.
Watershed infarction was present in 19% of study
population. Intracranial stenosis were identified as a significant
risk factors for both types of watershed infarction (cortical and
deep) (p=0,003, p=0,037 respectively). Extra cranial stenosis
were identified as a significant risk factors for deep watershed
infarction (p=0,020). Intracranial stenosis was present 43.6% of
patients, 27.3% were symptomatic and 16.3% were a
symptomatic. Hypertension were identified as a significant risk
factors for intracranial stenosis (p=0.045).