| Objective:(1)To explore whether preoperative heart rate variability can predict postoperative new atrial fibrillation(POAF)in patients undergoing cardiac valve surgery under cardiopulmonary bypass;(2)Explore the effect of remote ischemic preconditioning(RIPC)on preoperative heart rate variability in patients with heart valves;(3)To explore whether the delayed protective effect of RIPC can reduce the incidence of POAF in patients undergoing cardiac valve surgery under cardiopulmonary bypass through a prospective,randomized controlled study.Methods and results: This study is divided into three parts.Part one: Through retrospective study,to explore whether preoperative heart rate variability can predict POAF in patients undergoing cardiac valve surgery under cardiopulmonary bypass.Methods: Retrospective analysis of 283 patients undergoing extracorporeal circulation heart valve surgery at the Cardiology Department of the Northern Theater Command General Hospital of the Chinese People’s Liberation Army from January 2021 to December 2021.Grouping based on the occurrence of POAF: POAF(-)group(n=157),POAF(+)group(n=126),and then stratified by age into the elderly group(age ≥ 65 years old)and the young group(age<65 years old)for subgroup analysis.A comprehensive evaluation and analysis was conducted on whether the heart rate variability(standard deviation of NN interval(SDNN),the standard deviation of the mean value of NN interval of every five minutes(SDANN),the mean square root of the difference between consecutive NN intervals(RMSSD),the percentage of adjacent RR intervals>50ms(PNN50),low frequency component(LF),high frequency component(HF),and LF/HF)can predict POAF.Results: In the general population,the patients with POAF(+)were older and the LF/HF were lower.After multiple logistic regression analysis,only old age was the risk factor of POAF(P<0.05).The univariate analysis after stratification according to age showed that the population with POAF in young patients was older and had lower LF/HF(P<0.05).Part two: To evaluate the effect of remote ischemic preconditioning and explore the effect of RIPC on preoperative heart rate variability in patients undergoing cardiac valve surgery under cardiopulmonary bypass;Methods: From January 2022 to July 2022,screening was conducted among118 patients based on inclusion/exclusion criteria.58 patients were excluded,and 60 patients participated in this trial with informed consent and were randomly divided into a RIPC group(n=30)and a control group(n=30).Due to the cancellation of surgery,HRV data was missing.7 patients in the control group were excluded,and 5 patients in the RIPC group were excluded,23 patients in the final control group and 25 patients in the RIPC group were included in the analysis.Comparison of relevant indicators of heart rate variability(standard deviation of NN interval(SDNN),standard deviation of mean value of NN interval in every five minutes(SDANN),mean square root of difference between consecutive NN intervals(RMSSD),percentage of adjacent RR interval>50ms(PNN50),low frequency component(LF),high frequency component(HF)and LF/HF)at 8 hours in the morning on the surgical day between two groups of patients.Results: There was no statistical difference in baseline characteristics between the two groups,and there was no significant difference in heart rate variability24 hours before intervention(P>0.05).After the intervention measures were taken,the comparison of the results of heart rate variability at 8 hours on the day of operation showed that SDNN and SDANN of patients in RIPC group were higher than those in the control group,with statistical difference(P<0.05).Part three: Through a prospective,randomized controlled study,to explore whether the delayed protective effect of RIPC can reduce the incidence of POAF in patients undergoing cardiac valve surgery under cardiopulmonary bypass.Methods: From January 2022 to January 2023,287 patients were screened according to the inclusion/exclusion criteria,and 107 patients were excluded.Finally,180 patients participated in the trial with informed consent and were randomly divided into RIPC group(n=90)and control group(n=90).The main end point of the two groups was compared: the incidence of POAF(the occurrence of any rapid atrial arrhythmia lasting ≥30 seconds in the first 7 days after surgery);Secondary end points:postoperative complications(including acute renal injury,acute liver failure,hypoxemia,low cardiac output syndrome),ventilator use time,monitoring room time,postoperative hospitalization time,atrial fibrillation load(atrial fibrillation load is the percentage of atrial fibrillation duration7 days after surgery),atrial fibrillation at discharge,white blood cells,systemic immune inflammation index,IL-6,PCT,Hs-TNT,NT-Pro BNP at24 h,48h,72 h after surgery.Results: Among the 180 patients,there were 40 POAF patients(44.44%)in the control group and 35 POAF patients(38.89%)in the RIPC group,with no statistically significant difference(40 cases(40/90)vs 35 cases(35/90),P>0.05).There was no statistical difference between the two groups in perioperative mortality,incidence rate of acute renal failure and acute liver failure,postoperative blood transfusion,secondary tracheal intubation,thoracotomy and hemostasis,IABP assisted circulation,cardioversion,ICU time,ventilator assisted breathing time,Hs-TNT,NT-Pro BNP(P > 0.05).T The postoperative hospitalization days of patients in the RIPC group were significantly lower than those in the control group(P=0.036).In the population with POAF,the atrial fibrillation burden of the RIPC group was lower than that of the control group(P=0.023).At discharge,there were 13 patients with atrial fibrillation(14.44%)in the control group and 2 patients with atrial fibrillation(2.22%)in the RIPC group.There was a statistical difference between the two groups(P=0.005).Regression analysis found that age,hypertension,and application β The population of receptor blockers and the increase in left atrial diameter cause an increase in atrial fibrillation burden,while RIPC can reduce atrial fibrillation burden(P<0.05).Age and increased left atrial diameter are risk factors for continued atrial fibrillation at discharge,while RIPC is a protective factor(P<0.05).There was no statistical difference between the two groups in leukocytes,systemic immune inflammation index,IL-6,PCT,at 24 h,48h and 72h(P>0.05).However,it is interesting that the difference between the systemic immune inflammation index 24 hours after surgery and the systemic immune inflammation index 72 hours after surgery in the RIPC group is greater(P=0.045).Conclusion:(1)Age is a risk factor for POAF in patients undergoing cardiac valve surgery.In young patients undergoing cardiac valve surgery,the decrease of LF/HF is related to the occurrence of POAF;(2)RIPC can stabilize the preoperative heart rate variability of patients undergoing cardiac valve surgery;(3)The delayed protective effect of RIPC can not reduce the incidence of POAF in cardiac valve surgery under cardiopulmonary bypass,but can reduce the atrial fibrillation load of patients with POAF,reduce the postoperative hospitalization time,accelerate the decline of SII,and reduce the proportion of patients who still have POAF when discharged. |
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