Risk Factors for Low-Flow Related Ischemic Complications and Neurologic Worsening in Patients with Complex Internal Carotid Artery Aneurysm Treated by Extracranial to Intracranial High-Flow Bypass

BackgroundThe revascularization technique has remained indispensable for complex aneurysms. However, risk factors for low-flow related ischemic complications (LRICs) and neurologic worsening (NW) have been less well documented. We evaluated the risk factors for LRICs and NW in 67 patients treated with extracranial to intracranial bypass graft using radial artery or saphenous vein graft for complex internal carotid artery (ICA) aneurysm with ICA occlusion.MethodsIntraoperative middle cerebral artery pressure (MCAP) by backup superficial temporal artery to middle cerebral artery bypass was measured. The MCAP ratio was the ratio of the MCAP after release of the graft bypass to the initial MCAP. LRICs were defined as new neurologic deficits and ipsilateral cerebral blood flow reduction in single-photon emission computed tomography. Early and late NW were defined as an increase in 1 or more modified Rankin Scale at discharge and at the 12-month follow-up examination.ResultsDuring a median follow-up period of 13.3 months, LRICs were observed in 7 patients (10%). The Cox proportional hazards model showed that an MCAP ratio ≤0.80 was significantly related to LRICs. Multivariate logistic regression analysis revealed that perforating artery ischemia was significantly associated with early NW (n = 13, 19%) and late NW (n = 7, 13%). It also showed that LRICs were also significantly related to late NW.ConclusionsThe present study showed that regardless of the graft type, the MCAP ratio was associated with LRICs, which were related to late NW in patients with complex ICA aneurysms treated by extracranial to intracranial high-flow bypass graft.