Delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: proposal of an evidence-based combined clinical and imaging reference standard

Abstract

Aneurysmal subarachnoid hemorrhage is associated with high morbidity and mortality, with delayed neurologic deficits from delayed cerebral ischemia contributing to a large portion of the adverse outcomes in this patient population. There is currently no consensus reference standard for establishing the diagnosis of delayed cerebral ischemia either in the research or clinical settings, ultimately limiting strategies for preventing delayed infarction and permanent neurologic deficits. There are currently both clinical and imaging-based criteria for the diagnosis of delayed neurologic deficits and vasospasm, respectively, however, neither clinical nor angiographic assessment alone has been shown to identify patients who develop adverse outcomes from delayed infarction. Thus, the purpose of this work is to propose a 3-tiered combined imaging and clinical reference standard based on evidence from the literature to standardize the diagnosis of delayed cerebral ischemia, both to allow consistency across research studies and to ultimately improve outcomes in the clinical setting.

Fig 1.

Proposed multitiered reference standard in DCI. Three-tiered DCI reference standard algorithm, ordered from top to bottom. Asterisk indicates neuromonitoring devices such as cerebral microdialysis and oximetry. Double asterisks indicate whether the reference standard is used for clinical assessment and treatment decisions based on the risk/benefit ratio for treatment. If there is low risk, treatment for DCI is recommended. If there is high risk, the patient should re-enter the algorithm.