Fetal origin of posterior cerebral artery related to poor collaterals in patients with acute ischemic stroke.

The anatomic variation of Circle of Willis (CW) has been shown to have a great impact on its compensatory capacity during acute ischemic stroke. The purpose of the study was to evaluate the effect of variations in CW on collateral circulation in patients with acute ischemic stroke who had major artery occlusion. Patients with acute ischemic stroke within 4.5 h of stroke onset who had at least moderate severity of stroke (NIHSS ≥ 6), caused by major artery occlusion were included. Multiphase computed tomography angiography (CTA) was performed. Variations in CW on each patient were recorded and compared between those with poor collateral and intermediate-good collateral circulation. There were 66 patients. Mean NIHSS was 15. Forty patients had poor collateral circulation and 26 patients had intermediate-good collateral circulation. There were variations in CW: no visualized posterior communicating artery (PCOM) (31/66, 47%), fetal origin of posterior cerebral artery (25/66, 38%), one anterior cerebral artery, segment A1 (A1) hypoplasia or atresia (16/66, 24%), one PCOM (8/66, 12%), and complete CW (3/66, 5%). Fetal origin of posterior cerebral artery (PCA) was associated with poor collateral circulation (48% vs 23%, p-value = 0.046). This pilot study showed that the presence of fetal origin of PCA was associated with poor collateral circulation in patients with acute ischemic stroke caused by major artery occlusion.