One study evaluating the frequency of ACA embolism in 105 patients undergoing mechanical thrombectomy of occlusions of the M1 segment of the MCA identified 12 new ACA emboli (11.4% of studied cases). ĭistal vessel occlusion secondary to lost or fragmented thrombi associated with the use of intravenous thrombolysis and mechanical thrombectomy is another potential mechanism of ACA stroke. There are reported cases with unknown etiology in some case series. This mechanism has correlated with both unilateral and bilateral ACA infarcts. Reported triggers include subarachnoid hemorrhage and pituitary apoplexy. Less common mechanisms have been described, including vasculitis and coagulopathic states. Those with stroke secondary to arterial dissection also tend to be younger. While rarely reported on Western populations, other sources refer to a high prevalence among Japanese patients. Īnother significant mechanism of ACA stroke is arterial dissection. A hypoplastic or absent A1 segment is thought to facilitate embolic strokes due to increased vascular flow through the unique proximal section that branches off distally into the bilateral ACA’s. Some reports suggest that cardiac emboli are more frequently the cause of ACA as compared to MCA and posterior cerebral artery (PCA) infarcts. Ĭardiac embolism from different sources, including atrial fibrillation, intracardiac thrombus, valve disease, and tumors are other significant causes of ACA infarction. Atherosclerosis is the most frequently reported etiology among studies in patients of Asian origin. Atherosclerotic large vessel disease frequently results in stroke secondary to either local branch occlusion by plaque, artery-to-artery embolism, and in situ thrombosis, with the latter considered as being the most prevalent in ACA infarction. One clinical imaging study of anterior cerebral artery infarction mechanisms concluded that atherosclerotic disease-related stroke mechanisms in the ACA were similar to those associated with middle cerebral artery (MCA) atherosclerosis. Ītherosclerosis is a primary cause of ischemic stroke. Atrial fibrillation is another significant risk factor, its frequency surpassing that of dyslipidemia among patients with ACA stroke in one study. These underlie varied processes which ultimately result in atherosclerosis of large and small arteries. Hypertension, hypercholesterolemia, diabetes mellitus, and smoking are known risk factors of the cardiovascular disease frequently found in stroke patients. The most recognizable patterns are the azygos, bihemispheric, and ACA with hypoplastic or absent A1 segment. These are rare and characteristically occur because of clinically significant anatomical variations affecting both ACA's at any point along its course. Notably, infarctions simultaneously affecting both cerebral hemispheres may also be present among ACA stroke cases. A significant feature of the ACA is its robust anastomotic complex this may account for the low rate of infarcts in this vascular distribution. The ACA itself often divides into five segments, usually labeled as A1 through A5, or as proximal (A1), ascending (A2, A3), and horizontal segments. These include Heubner’s, orbitofrontal, frontopolar, anterior internal frontal, middle internal frontal, posterior internal frontal, paracentral, superior parietal, inferior parietal, pericallosal, and callosomarginal arteries. Superficial and deep branches emerge along its course. Each ACA then advances between the two cerebral hemispheres and over the callosal sulcus in a posterior direction towards the parieto-occipital sulcus. Near this point, the anterior communicating artery (ACoA) forms, creating an anastomosis between both ACA’s. It then continues anteromedially towards the longitudinal fissure. The ACA emerges from the anterior clinoid segment of the internal carotid artery. However, it is possible that the peculiar manifestations of its clinical syndromes and the suspicion that many infarcts in this arterial territory are silent could result in the underdiagnosis of strokes involving the ACA or its branches.

The risk factors and etiology of strokes in this vascular territory are largely the same as for the other principal cerebral arteries including hypertension, dyslipidemias, diabetes mellitus, smoking, atherosclerosis, and cardioembolism. Infarcts involving the territory of the anterior cerebral artery (ACA) are uncommon, accounting for a considerably small share of the total number of ischemic infarcts.

Pica distribution stroke