Research On Radiofrequency Ablation Modified MAZE In Patients With Valvular Atrial Fibrillation

Part I Comparison of modified MAZE with minimally invasive monopolar ablation and traditional bipolar radiofrequency ablation in the treatment of Valvular atrial fibrillationObjective: Atrial Fibrillation(AF)is one of the most common arrhythmia in adults of modern society.The most effective surgical treatment for atrial fibrillation is radiofrequency ablation modified MAZE.At present,there is still controversy about the efficacy of the modified MAZE procedure for minimally invasive monopolar radiofrequency ablation and traditional bipolar radiofrequency ablation.The purpose of this study is to compare the effects of these two radiofrequency ablation MAZE procedures in patients with Valvular atrial fibrillation.Methods: 275 patients who underwent radiofrequency ablation of Valvular atrial fibrillation from November 2014 to November 2020 in the Department of Cardiovascular Surgery,the First Affiliated Hospital,College of Medicine,Zhejiang University,were classified into minimally invasive monopolar radiofrequency ablation group(hereinafter referred to as the monopolar group)and the traditional bipolar radiofrequency ablation group(hereinafter referred to as the bipolar group).Among them,patients with a history of atrial fibrillation less than two years and a left atrial diameter <60 mm with mitral valve disease can be included in the study.31 patients who did not meet the above conditions were excluded.12 people were excluded due to lack of preoperative echocardiography or other baseline data,and 7 people were excluded due to loss of follow-up after surgery.In the end,225 patients completed the study,including 79 in the monopolar group and 146 in the bipolar group.SPSS and Prism were used for data analysis.ECG and transthoracic echocardiography were performed at 3 months,6 months,12 months after operation and at least once a year after that.The primary outcome event was recurrence of atrial fibrillation or atrial flutter.At the same time,we also evaluated the patients’ quality of life through SF-36 scores at 3 months,6 months,and 12 months after operation.Results: Preoperative LVDs(34.0 mm vs 32.0 mm,P=0.003),intraoperative extracorporeal circulation time(109.32 min vs 99.69 min,P=0.005),blocking time(76.0 min vs 59.0 min,P<0.001),the proportion of peer mitral valvuloplasty(30.4% vs 17.8%,P=0.043),the proportion of temporary pacemaker placement(73.4% vs 53.4%,P=0.004),the proportion of left atrial appendage suture treatment(82.3 % vs 34.2%,P=0.005)in monopolar group were higher than those in the bipolar group.In the bipolar group,the proportion of mitral valve replacement(82.2% vs 69.6%,P=0.043),the proportion of tricuspid valvuloplasty(65.1% vs 29.1%,P<0.001),the proportion of left atrial appendage ligation(64.4% vs 8.86%,P<0.001)and the proportion of L-carnitine used during hospitalization(72.6% vs 58.2%,P=0.036)were higher than those in the monopolar group.In the postoperative follow-up,the proportion of sinus rhythm in the monopolar group and the bipolar group was no significant differences at discharge(89.87% vs 82.76%,P=0.172),at 3 months(82.29% vs 75.17%,P=0.244),at 6 months(76.71% vs 71.64%,P=0.511)and at 12 months after operation(72.13% vs 66.95%,P=0.478).However,the SF-36 scale score of the monopolar group were significantly higher than those in the bipolar group at 3 months(120.61 points vs 110.21 points,P<0.001),at 6 months(121.20 points vs 112.18 points,P<0.001),and at 12 months after operation(122.80 points vs 118.40 points,P<0.001).There was no significant difference in Kaplan-Meier survival curve between the two groups.Log-rank test P=0.636.Conclusions: This study is different from the previous radiofrequency ablation MAZE with large median sternal incision.For the first time,the minimally invasive monopolar radiofrequency ablation MAZE on the right chest was compared with the bipolar radiofrequency ablation MAZE with large median sternal incision.And the proportion of sinus rhythm after operation was no statistically significant difference between the monopolar group and the bipolar group.Which means,the minimally invasive monopolar radiofrequency ablation MAZE on the right chest was not inferior to the bipolar radiofrequency ablation MAZE with large median sternal incision.According to the SF-36 scale score,the score of the monopolar group was significantly higher than that of the bipolar group.Therefore,in terms of postoperative quality of life recovery,the monopolar group was better than the bipolar group.Part II Research on Risk Factors and Predictive Models of Valvular Atrial Fibrillation Recurrence After Radiofrequency AblationObjective: 15-35% of patients with Valvular atrial fibrillation have a probability of recurring atrial fibrillation or atrial flutter after radiofrequency ablation.The relevant factors for the recurrence of postoperative atrial fibrillation have not been fully clarified.The purpose of this study is to find out risk factors of postoperative atrial fibrillation in patients with Valvular atrial fibrillation,and to establish predictive models of atrial fibrillation recurrence.Methods: 225 patients(same as Part I)who underwent radiofrequency ablation of nonisolated atrial fibrillation from November 2014 to November 2020 in the Department of Cardiovascular Surgery,the First Affiliated Hospital,College of Medicine,Zhejiang University,were also included in Part II,excepted for 1 patient who was discharged automatically during the hospitalization period.The remaining 224 patients were all included in Part II.SPSS,X-tile,R studio were used for statistical analysis.In addition,a continuous collection of left atrial myocytes from 21 patients with non-solitary atrial fibrillation who underwent radiofrequency ablation of atrial fibrillation at the Department of Cardiovascular Surgery,the First Affiliated Hospital,College of Medicine,Zhejiang University from November 1,2020 to December 31,2020.The specimens were subjected to RNA sequencing and analysis,and were divided into two groups according to the electrocardiogram results at 3 months after the operation.Results: The retrospectively enrolled 224 patients were divided into training set and validation set according to the ratio of 3:1.The training set was analyzed by univariate and multivariate Cox regression analysis.It was found that preoperative uric acid >401 μmol/L(P=0.006),B-type natriuretic peptide >202 ng/L(P=0.042),hypersensitivity C-reactive protein >6.1 mg/L(P=0.026),erythrocyte sedimentation rate >7.0 mm/h(P= 0.016),preoperative LAD >48 mm(P=0.031)were significantly correlated with the recurrence of atrial fibrillation after radiofrequency ablation in patients with Valvular atrial fibrillation.In the training set,a Cox regression model of the five related factors was established through the R language.The C-index of the model was 0.82,and the area under the ROC curve was 0.831(P<0.001).Internal verification was carried out in the training set,and it was found that the fit of the internal verification curve was relatively good at 3 months,6 months,1 year,and 3 years after the operation.After calculating the weight of each related factor through the nomogram,a new risk predictive model "BLUCE" for postoperative atrial fibrillation was established.In the model,patient whose uric acid >401 μmol/L scored 7.99,B-type natriuretic peptide >202 ng/L scored 3.13,hypersensitive C-reactive protein >6.1 mg/L score 10,erythrocyte sedimentation rate >7.0 mm/h score 7.64 and LAD >48 mm score 4.6.This model was divided into 3 levels according to the score-less than 5 points belonged to low-risk level,5-15 points belonged to medium-risk level,and greater than 15 points was divided into high-risk level.Kaplan-Meier survival analysis was performed in the training set and the total patients according to the 3 levels.P values of Log-rank test were both <0.001,while in the validation set,P value was 0.057.In the validation set,the BLUCE Cox regression model was established through R language.The C-index of the model was 0.64,the area under the ROC curve was 0.698(P=0.016),and also external verification was performed.It was found that the fit of the external verification was relatively good at 3 months,6 months,1 year,3 year after operation.After RNA sequencing and analysis of 18 left atrial myocardial samples from patients with Valvular atrial fibrillation,it was found that some genes related to the PPAR signaling pathway were highly expressed in patients with postoperative atrial fibrillation,including ACSL,SLC27A(FATP),OLR1,SORBS1(CAP),etc.And some genes related to the Th1/Th2 differentiation signal pathway were low expressed in the AF group,including HLA-DRB1,HLA-DRB5,IL2 Ra,CD4,etc.Conclusion: For patients with Valvular atrial fibrillation,preoperative uric acid>401 μmol/L,preoperative B-type natriuretic peptide>202 ng/L,preoperative hypersensitivity C-reactive protein>6.1 mg/L,preoperative erythrocyte sedimentation rate>7.0 mm /h,preoperative LAD>48 mm are risk factors for atrial fibrillation or atrial flutter recurrence after radiofrequency ablation.The BLUCE predictive model can distinguish the high-risk groups of postoperative atrial fibrillation.Patients with high-risk level in BLUCE model are more likely to recur atrial fibrillation after radiofrequency ablation,and the proportion of sinus rhythm of high-risk level patients is significantly lower than that of medium-risk and low-risk patients.In addition,through KEGG enrichment analysis,it was found that the mechanism of AF recurrence after radiofrequency ablation is related to the PPAR signaling pathway and the Th1/Th2 differentiation signaling pathway.