Effects Of Recombinant Human Brain Natriuretic Peptide Pretreatment On Cardiac Function In Patients Undergoing Valve Replacement

Background:Poor preoperative cardiac reserve capacity causes low tolerance of myocardial ischemia-reperfusion in patients undergoing cardiac valve replacement.The beneficial hemodynamic effects of recombinant human brain natriuretic peptide（rh BNP）to patients with heart failure have been demonstrated.In most previous studies on perioperative myocardial protection,researchers have focused on the intraoperative and postoperative application of rh BNP.Objectives:This study was designed to investigate the effect of preoperative addition of rh BNP on the perioperative cardiac function in patients undergoing valve replacement following cardiopulmonary bypass（CPB）by observing imaging,laboratory and histopathological changes,thereby providing new clinical ideas for the improvement of perioperative cardiac function.Methods:Between November 2019 and November 2020,20 patients,undergoing cardiac valve replacement following CPB,were randomly enrolled in either an efficacy trial（group A）or a comparative trial（group B）,10 in each.In group A,patients received rh BNP(infused at a rate of 0.01μg·kg^-1·min^-1)for 72 hours based on the conventional treatment from 3 days before the operation.Patients received routine treatments in group B.The targeted laboratory indexes,including serum creatine kinase（CK）,creatine kinase isoenzyme（CK-MB）,lactate dehydrogenase（LDH）,myoglobin（MB）,cardiac troponin I（c Tn I）,B-type natriuretic peptide（BNP）,plasma procalcitonin（PCT）,serum soluble ST2（s ST2）and malondialdehyde（MDA）,were detected at 1 day before operation（T0）,before aortic cross-clamping（T1）,12 hours after aortic opening（T2）,24 hours after aortic opening（T3）and 7 days after the operation（T4）.The right atrial appendage tissue was taken for histopathological analysis before CPB.Echocardiography was performed T0and T4 to measured and compared the ejection fraction（EF）,stroke volume（SV）,cardiac index（CI）and right ventricular end-systolic area.Results:No postoperative complications and major adverse cardiovascular events occurred in the two groups during the study period.No differences in the overall distribution of most targeted laboratory indexes left were observed in the two groups（P>0.05）,but the serum s ST2 level at T3 and MDA concentration at T1 in group A were lower than those in group B（P<0.05）.The values of EF in group A were lower than those in group B at T0 and T4（P<0.05）,but the differences of SV and CI were not significant（P>0.05）.The right atrial end-systolic areas at T4 were smaller than those at T0 in both groups（P<0.05）.None of the histological features in the right atrial appendages differed in both groups,and the collagen volume fraction was no statistical significance（P>0.05）.Conclusion:Preoperative application of rh BNP has a protective effect on the myocardium of patients with valve replacement during the perioperative period.It promotes the recovery of cardiac function after the operation,associated with the improvement of preoperative heart function of patients to a certain extent.However,the effect of the preoperative application of rh BNP on intraoperative oxidative stress resistance is temporary and it has no significant effect on postoperative anti-infective ability and myocardial pathological changes.