Left carotid aneurysm requires surgery. 1. Aneurysm is due to a localized lesion of the arterial wall, which causes the arterial wall to form a permanent bulge outward, and the wall of the lesion area becomes thin and fragile, which makes it easy to form blood clots. At present, the effect of conservative treatment is not obvious, and because the aneurysm is easy to rupture, and after rupture, it is life-threatening due to hemorrhage, so surgery is recommended. Carotid artery compression test can be performed before surgery for unruptured carotid aneurysm. 2. Carotid aneurysm is an aneurysm-like protrusion of cerebral blood vessels due to abnormal local vascular changes, and surgical treatment is the only possible cure. In addition to cerebral infarction caused by carotid aneurysm thrombosis, or thrombus dislodgement, which affects cerebral blood supply, the more serious complication is rupture of the aneurysm, which causes fatal hemorrhage. Therefore, once left carotid aneurysm is diagnosed, it should be treated by surgery as soon as possible.