Protective Effect And Mechanism Of Remote Ischemic Preconditioning On Cardiac Function And Clinical Prognosis In Patients Undergoing Cardiac Valve Replacement Under Cardiopulmonary Bypass

Research Background:Patients undergoing cardiac surgery under cardiopulmonary bypass(CPB)often have clinical or subclinical cardiac insufficiency during the perioperative period.The main clinical manifestations are pulmonary edema and hemodynamic disorder,but the mechanism of action still needs further study.There is evidence that the heart and other organs can be protected from ischemia/reperfusion injury by applying one or more transient ischemic and reperfusion cycles to the distal organ or tissue.This process is called remote ischemic preconditioning(RIPC).As a simple and effective method,RIPC has been proven to protect the vital organs such as heart and brain,but its protective effect on perioperative cardiac function in patients undergoing cardiac valve replacement under CPB is not clear.Although the current mechanism of RIPC is not fully understood,it has been shown to reduce the extent of perioperative myocardial damage in patients.Whether RIPC can improve the clinical outcome of patients undergoing cardiac surgery remains to be further explored.In this study,patients undergoing cardiac valve replacement under CPB were enrolled and RIPC was given to investigate the effect of perioperative cardiac function and clinical prognosis on patients undergoing surgery.Objective:This study is to investigate the effect of RIPC on perioperative cardiac function and clinical prognosis in patients undergoing cardiac valve replacement under CPB.Methods:From January 2018 to August 2018,60 patients underwent cardiac valve replacement under CPB under general anesthesia in the Department of Anesthesiology,Henan Provincial Chest Hospital.All patients were divided into two groups according to the random number table method:control group and RIPC group,30 cases in each group.All patients undergoing surgery are performed by the same team of surgeons.Patients included in the study included criteria:no gender restrictions,age 40 to 65 years,weight 50.0 to 80.0 kg,height 150.0 to 180.0 cm,American Society of Anesthesiologists(ASA)classification ?to ?,New York Heart Association(NYHA)Heart function grade ?/?,left ventricular ejection fraction(EF%)>40%.Patients in the RIPC group underwent limb remote ischemic preconditioning 5 min after induction of anesthesia.The specific steps are as follows:the cuff is placed on the upper arm of the right upper limb,and the pressure is?200 mmHg after inflation and pressure.After 5 minutes,the cuff is deflated to 0 mmHg,and then inflated and pressurized again after 5 minutes,so that 3 cycles are performed,and in the C group,the cuff was tied to the patient's right upper limb but is not inflated and deflated.Record general clinical data of preoperative patients.The patients underwent preoperative(T0),1 h(T1)after aortic opening,6 h(T2),12 h(T3),and 24 h(T4),and the patients were treated with fluorescent immunosorbent assay.Plasma levels of amino-terminal.B-brain natriuretic peptide(NT-proBNP),cardiac troponin(cTnI),plasma creatine kinase(CK),and creatine kinase isoenzyme(CK-MB)concentrations were measured.Cardiac function index detection:Left ventricular end-diastolic diameter(LVEDD),left ventricular end-systolic diameter(LVESD),left ventricular ejection fraction(LVEF)index were measured by cardiac color Doppler instrument Philip IE 33 before and 4 weeks after surgery.Level.Blood routine examinations were performed at 1 day,2 days,3 days,and 5 days after surgery,and white blood cells(WBC)and neutrophil counts(PMN)and neutrophil percentage(PMN%)were recorded.The amount of vasoactive drugs,CPB time,ascending aorta block time,chest closing time and operation time were recorded in the two groups.The postoperative chest opening hemostasis rate and postoperative complications were recorded in the two groups.The input volume of blood products such as chest drainage,red blood cell suspension,fresh frozen plasma,cryoprecipitate and platelets within 24 hours after surgery was recorded.ICU stay time and hospital stay and all-cause mortality at 30 days postoperatively were recorded.The primary end point was cardiovascular adverse events and cerebrovascular adverse events within 30 days after surgery.These include cardiac death,nonfatal myocardial infarction,congestive heart failure,nonfatal cardiac arrest,coronary revascularization,or stroke;secondary endpoints include myocardial injury within 30 days after surgery,acute Kidney damage,acute lung injury(ALI),continuous renal replacement therapy(CRRT),neurological dysfunction.Results:1.There were no significant differences in age,sex ratio,ASA grade,body mass index(BMI),left ventricular ejection fraction,and valve replacement between the two groups(P>0.05).2.Compared with the control group,plasma NT-proBNP levels,cTnI,CK and CK-MB concentrations were significantly decreased in the RIPC group from T1 to T4(P<0.05).3.There were no significant differences in preoperative cardiac function indexes LVEDD,LVESD and LVEF between the two groups(P>0.05).LVEDD and LVESD were significantly lower in the RIPC group than in the control group at 4 weeks postoperatively,while LVEF was higher than the control group(P<0.05).4.Compared with the control group,the WBC,PMN and PMN%of the RIPC group were significantly decreased at 1 d,2 d,3 d and 5 d after operation(P<0.05).5.the two groups of patients within 24 hours after surgery such as allergic reactions,renal insufficiency and liver dysfunction,and the incidence of thrombosis and mortality,the difference did not show statistical significance(P>0.05).6.There were no significant differences in postoperative mechanical ventilation time,ICU stay time,sinus bradycardia,hypotension and re-tracheal intubation between the two groups(P>0.05).7.There was no significant difference in CPB time,ascending aorta occlusion time,chest closing time,deep hypothermic circulatory time and operation time between the control group and the RIPC group(P>0.05).8.Compared with the control group,there was no significant difference in the input volume of blood products such as chest drainage,red blood cell suspension,fresh frozen plasma,cryoprecipitate and platelet in the RIPC group within 24 hours after operation(P>0.05).9.Comparison of the incidence of cardiovascular adverse events and cerebrovascular adverse events within 30 days after surgery:2 cases and 1 case of cardiac death in the control group and RIPC group,respectively,the incidence rate was 6.7%,3.3%;non-lethal Myocardial infarction was 0 cases and 1 case,respectively,the incidence rate was 0,3.3%;congestive heart failure was 2 cases,3 cases,the incidence rate was 6.7%,10.0%;non-fatal cardiac arrest respectively 1 case,0 cases,the incidence rate was 3.3%,0%;coronary revascularization was 0 cases,1 case,the incidence rate was 0%,3.3%;stroke cases were 0 cases,0 cases The incidence rates were 0 and 0 respectively;there was no significant difference between the above indicators(P>0.05).10.There was no difference in the incidence of postoperative second-open thoracic hemostasis and postoperative complications such as myocardial injury,ALI,AKI,CRRT,transient neurological dysfunction,permanent neurological dysfunction,and mortality.Statistical significance(P>0.05).Conclusion:RIPC can improve the perioperative cardiac function of patients undergoing heart valve replacement surgery under CPB,improve the clinical prognosis of patients,and have better cardioprotective effect on patients with such surgery,but its mechanism needs further discussion.