Occipital infarction: Carotid artery and cardiac findings

Extracranial carotid artery disease can cause occipital infarction when the posterior cerebral artery originates from the carotid artery. To determine the prevalence of serious extracranial carotid artery stenosis (≥50%) and potential stroke mechanisms in patients with posterior cerebral artery territory occipital infarcts, we studied 24 consecutive patients with recent infarcts documented on computed tomography or magnetic resonance imaging. All patients presented with a homonymous visual field defect, and eight also had other cerebral dysfunctions. Eighteen patients had carotid studies: duplex ultrasound in 17 and arteriography in 1. Twenty patients had echocardiography. Presumed mechanisms of infarction were cardiac embolism in 10 patients (42%), hypercoagulability in 2 (8%), artery-to-artery embolism in 1 (4%), migraine in 1 (4%), multiple potential mechanisms (cardiac embolism, hypercoagulability, and migraine) in 1 (4%), and undetermined in the remaining 9 (38%). None of the patients had extracranial carotid artery stenosis ≥50%. Extracranial carotid artery disease appears to be a rare cause of occipital infarction. Our findings support conclusions reached in previous studies, that cardiac embolism is the principal cause of occipital infarction.