The Role of Autonomic Dysfunction, and Its Association with Inflammation, Cerebral Blood Perfusion and Autoregulation in Critical Patients with Acute Ischemic Stroke

Stroke has been shown to alter autonomic nervous system (ANS) function and raise susceptibility to sudden death. The localization of stroke may have differential effects on ANS function. Prior investigators have demonstrated that infarction of brain stem or hemisphere with insular involvement is related to autonomic dysfunction and may predict poor clinical outcome. For assessing autonomic regulation, analysis of heart rate variability (HRV) and baroreceptor sensitivity (BRS) have become an important widely used method. The use of spontaneous BRS and HRV might open the way to longitudinal studies in predicting cardiovascular events in severe stroke patients who are unable to usethe interventional methods. Cerebral autoregulation (CA) is the ability of the brain to maintain relatively constant cerebral blood flow (CBF) despite changes in perfusion pressure. Previous investigations have found that dynamic CA is impaired after acute ischemic stroke. Although the approach of dynamic CA with non-invasive beat-to-beat BP monitors and transcranial Doppler is convenient, the method has its limitations. Arterial spin labeling (ASL)- MR perfusion imaging is an assessable way to evaluate the CA and CBF without ionizing radiation and without repeated administration of contrast agents. Previous experimental and clinical researches have addressed that inflammatory reactions can be modulated by the activity of the ANS. However, the exact relationship between cardiac autonomic function and inflammation remains to be elucidated. There were even fewer studies assessing the role of inflammation on the CBF, dynamic CA, and their clinical significance after acute ischemic stroke. In present project, we will prospectively enrolled patients with moderate to severe ischemic stroke (NIHSS ＞8) who are admitted to ICU in Kaohsiung Chang Gung Memorial hospital. The purpose of the study is to (1) assess serially the changes of autonomic dysfunction and autoregulation activity in patients with acute severe ischemic stroke; (2) analyze the correlation between HRV-related ANS function and the cerebral blood perfusion measuring by ASL-MRI; (3) explore whether a relationship between impaired ANS function and inflammation also exists in stroke patients; and (4) evaluate the predictive values of inflammatory markers, CA and ANS function on the clinical outcomes of acute ischemic stroke.

Project ID:PC10207-0348
External Project ID:NSC102-2314-B182-032