Disappearance of Ruptured Posterior Cerebral Artery Aneurysm Associated with Internal Carotid Artery Occlusion After Superficial Temporal Artery−to−Middle Cerebral Artery Bypass

Abstract

Internal carotid artery (ICA) occlusion associated with posterior cerebral artery (PCA) aneurysms is regarded as a rare cerebrovascular disease. Common treatment of aneurysms-direct clipping or coiling-is not taken into consideration for this kind of cerebrovascular property. Combined surgical cerebrovascular reconstruction of the superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass offers a chance to downregulate the hemodynamic stress of aneurysm rupture. A 46-year-old female presented with a fever and headache 1 month ago. An axial computed tomography scan showed a subarachnoid hemorrhage (SAH). Digital subtraction angiography (DSA) was conducted, and the patient received an STA-MCA bypass following medical treatment for 1 month in the local hospital. Computed tomography angiography and DSA demonstrated an aneurysm located on the right PCA and an occlusion of the right ICA in our hospital. Three days after admission, the right STA-MCA bypass was performed. The patient suffered no neurologic deterioration and lived a normal life. 6 months after the STA-MCA bypass, DSA of the right vertebral artery revealed disappearance of the aneurysm located on the right PCA (P2 segment). Owing to ICA occlusion, the gap of hemodynamic stress between the posterior segment of the circle of Willis and anterior segment of the circle of Willis enlarged. This may lead to a ruptured PCA aneurysm. In this case, the aneurysm disappeared following an STA-MCA bypass. STA-MCA bypass may be one of the major reasons downregulating the gap, which can be regarded as an effective option concerning such aneurysms.