We sought to determine the prevalence of fetal posterior cerebral artery (fPCA) and if fPCA was associated with specific stroke etiology and vessel territory affected. This paper is a retrospective review of prospectively identified patients with acute ischemic stroke from July 2008 to December 2010. We defined complete fPCA as absence of a P1 segment linking the basilar with the PCA and partial fPCA as small segment linking the basilar with the PCA. Patients without intracranial vascular imaging were excluded. We compared patients with complete fPCA, partial fPCA, and without fPCA in terms of demographics, stroke severity, distribution, and etiology and factored in whether the stroke was ipsilateral to the fPCA. Of the 536 included patients, 9.5% ( ) had complete fPCA and 15.1% ( ) had partial fPCA. Patients with complete fPCA were older and more often female than partial fPCA and no fPCA patients, and significant variation in TOAST classification was detected across groups ( ). Patients with complete fPCA had less small vessel and more large vessel strokes than patients with no fPCA and partial fPCA. Fetal PCA may predispose to stroke mechanism, but is not associated with vascular distribution, stroke severity, or early outcome. 1. Introduction Fetal PCA (fPCA) is a common variant of cerebral circulation. Two definitions of fPCA exist in the literature: complete fetal PCA and partial fetal PCA. Complete fetal PCA (cfPCA) is defined as posterior cerebral artery that completely originates from the internal carotid artery ICA with no connection with the basilar artery. Partial fetal PCA (pfPCA) is defined as posterior cerebral artery originating from ICA with a small, or atretic, connection with the basilar. Available studies have largely used the pfPCA definition. Variable prevalence of fPCA has been demonstrated in healthy subjects (15–32%) and those with cerebral infarction (5–36%) using autopsy or magnetic resonance angiography (MRA). Unilateral pfPCA is more frequent (11–29%) than bilateral pfPCA (1–9%). Unilateral cfPCA was detected in 4–26% of cases with only 2–4% having bilateral cfPCA. Prevalence was lower with MRA than autopsy [1]. Study population (healthy subjects versus cerebral infarction) did not influence the fPCA prevalence [1]. cfPCA can impact the anatomy of the cerebral circulation. More area is perfused by the anterior circulation as PCA is completely supplied by ICA. In addition, leptomeningeal collaterals fail to develop between the ICA and the vertebrobasilar system since both the MCA and the PCA are connected to the internal
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