Effect Of Remote Ischemia Precondition At Different Time On Postoperative Neurocognitive Function In Patients With Carotid Endarterectomy

Objective To investigate the effect of different time windows of remote ischemic pretreatment?RIPC?on the cognitive function of patients with carotid endarterectomy?CEA?.Methods Recruit 60 patients with elective CEA surgery who meet the requirements of the trial,age 50?80 years old,sex unlimited,ASA grade???,New York Heart Association?NYHA?cardiac function grade???.control group?C group,n=20?,preoperative 60 min administered RIPC group?RIPC?group,n=20?,preoperative 24 h administered RIPC group?RIPC?group,n=20?.Exclusion criteria:patients with no clinical symptoms,but no carotid stenosis or mild stenosis?stenosis degree<50%?or no diagnosis of carotid angiography;patients with non-first-time diagnosis who have performed CEA or CAS in the hospital;patients with abnormal coagulation system function or who cannot be surgically treated with severe heart,lung disease or other diseases;those with incomplete medical history information;patients with cognitive impairment disease themselves,who cannot score cognitive functions.A tourniquet was placed at the middle and lower 1/3 junction of the right lower extremity of the patient,pressurized to 200 mm Hg,and treated with 3 cycles of 5 min ischemia/5 min reperfusion.The control group only placed the tourniquet in the same position without pressure.ECG,noninvasive blood pressure?NIBP?,heart rate?HR?,pulse oxygen saturation?SPO₂?were monitored after entering the room.the radial artery puncture catheterization was performed under local anesthesia and the flutrac/viglio system was connected to monitor arterial blood pressure?IBP?.After carotid artery opening,the pump was injected with nitroglycerin from 0.2 to 5.0?g.kg^-1.min^-1 to avoid excessive blood pressure and basically maintain blood pressure at-20%of the base value.Long intraoperative?above 5min?hypotension?above 30%below the underlying value?could not be improved,bleeding volume over 800 ml or intraoperative monitoring of intracranial pressure below 45 mm Hg.Serum levels of brain-derived nutrient factor?BDNF?,GFAP were measured in three groups of patients 1 day before operation(t₀,6hours after operation?t₁?and 24 hours after operation?t₂?.Results?1?the serum brain injury related markers GFAP of the three groups were significantly higher than those of the preoperative basal levels?P<0.05?,GFAP was improved 24 hours after operation compared with 6 hours after operation;the levels of serum GFAP in t₁ and t₂ were significantly lower in the RIPC?group and RIPC?group than in the control group?P<0.05?,and the RIPC?group was significantly lower than RIPC?group?P<0.05?.?2?Compared with t₀,the levels of BDNF in the three groups increased significantly at t₁,and BDNF in the RIPC?group and RIPC?group were still higher at t₂?P<0.05?,and were significantly higher than those in the control group?P<0.05?,while BDNF in the RIPC?group was significantly higher than that in the RIPC?group at t₂?P<0.05?.?3?There was no significant difference in MMSE scores between the three groups at t₃?t₄?t₅ postoperative time compared with t₀?P>0.05?.There was no significant difference in the three groups before operation on digital symbol replacement test,Hopkins speech learning test score,and graph memory delay score.In the control group and RIPC?group at t₃ time,the above three scores were significantly reduced?P<0.05?compared with preoperative scores,while RIPC? group had no significant difference in graph delayed memory and digital symbol replacement test scores?P>0.05?.The control group at t₄ moment was still lower than preoperative?P<0.05?in the graph memory delay score,and there was no difference between the other tests and the preoperative score.RIPC?group had significantly higher scores for graphical delayed memory and digital symbol replacement tests at t₃times than RIPC?and control groups?P<0.05?and had no significant difference ?P>0.05?with preoperative.?4?There were 8 cases of delayed cognitive recovery in control group,3 cases in RIPC?group and 2 cases in RIPC?group 7 days after peration,the DNR incidence of control group,RIPC?group and RIPC?group were 44.4%,15.8%and 10.5%,respectively,there was statistical difference in incidence among the three groups??2=6.855,P<0.05?;There were 4 cases in control group,3 ases in RIPC?group and 1 case in RIPC?group with delayed neurocognitive recovery,there was no statistical difference between the three groups??2=2.224,P>0.05?;Three cases of neurocognitive impairment occurred in the control group in 3months after operation,2 in RIPC?group and 1 in RIPC?group,there was no tatistical difference in incidence among the three groups??2=1.258,P>0.05?.Conclusion?1?Patients with carotid endarterectomy suffered from a certain degree of cerebral ischemia and reperfusion injury,the expression of brain injury related markers increased,and the scores of neuropsychological tests showing delayed memory,graphic reconstruction and visual spatial ability decreased;?2?The remote ischemic preconditioning can alleviate the postoperative brain injury,improve the recovery of neurocognitive function within one month after CEA operation,and the protective effect of delayed phase?24 hours before operation RIPC?is more obvious,which may be related to its continuous promotion of endogenous BDNF generation.