The Efficacy Of Monitoring Of Cerebral Blood Flow By The C-FLOW In Carotid Endarterectomy

Objective: To prospectively investigate the efficacy of monitoring of cerebral blood flow by c-FLOW in carotid endarterectomy.Methods: We enrolled 73 consecutive patients who accepted CEA in Department of Neurosurgery, Xuan Wu Hospital of Capital Medical University from August 2015 to March 2016. All patients had undergone the c-FLOW and TCD monitoring during the operation under general anesthesia. The intraoperative TCD monitoring was set as the gold standard. Changes from baseline values of CFI and V-MCA were recorded following carotid artery clamping and declamping. Based on the four-fold tables, sensitivity and specificity of detection for intraoperative hypoperfusion and postoperative hyperperfusion by c-FLOW were calculated. The correlation analysis was conducted for c-FLOW and TCD monitoring values. The ROC analysis was also performed to determine the optimal cut-off for CFI changes to identify intraoperative hypoperfusion and postoperative hyperperfusion.Results: 1. Among the 73 patients, 10 showed significant decrease of V-MCA following carotid clamping, only 4 of them accepted intraoperative shunting according to the surgeon’s decision. The sensitivity and specificity of detection for intraoperative hypopersion by c-FLOW were 70.0% and 93.7%, respectively, with a Kappa value of 0.75. The Pearson correlation index between CFI and V-MCA was 0.647(P<0.001). A cut-off of 21% decrease of CFI was identified as optimal to detect the intraoperative hypoperfusion and the c-FLOW exhibited a high discriminative power of 0.929(95%CI 0.865-0.994, P<0.001) area under ROC curve in detecting 50% V-MCA decline. 2. Following the declamping, 7 patients were diagnosed as hyperperfusion by TCD monitoring. The sensitivity and specificity of detection for postoperative hyperpersion by c-FLOW were 57.1% and 95.5%, respectively, with a Kappa value of 0.83. The Pearson correlation index between CFI and V-MCA was 0.286(P=0.014). A cut-off of 15% increase of CFI following carotid declamping was identified as optimal to detect the postoperative hyperperfusion and the c-FLOW exhibited a modest discriminative power of 0.688(95%CI 0.421-0.956, P=0.103) area under ROC curve in detecting 100% V-MCA increase. 3. After operation, no patient showed ischemic injury through a physical examnation. No death and stroke occurred during the postoperative hospitalization. One patient showed suspicious CHS symptom after operation with no positive imaging findings, and soon recovered following rational therapy. Additionally, 3 patients who suffered from TIA, cranial nerve injury and pulmonary infection after operation also got uneventful recovery.Conclusions: As a new cerebral blood flow monitor, the c-FLOW could continuously and non-invasively monitor the CBF in real-time during CEA. We found that it could detect the intraoperative hypoperfusion and postoperative hyperperfusion effectively, so in may serve as a favorable substitute for TCD in future intraoperative monitoring.