Risk Factors Of New-Onset Left Bundle Branch Block Follows Transcatheter Aortic Valve Replacement And Impact On Left Ventricular Reverse Remodeling

Objectives:After transcatheter aortic valve replacement(TAVR)in patients with severe aortic stenosis(AS),beneficial ventricular retro-remodeling will occur with reduced left ventricular pressure load.Left bundle branch block(LBBB)is a common conduction disorder after TAVR.Therefore,the purpose of this study was to explore the risk factors of new-onset LBBB follows TAVR in patients with symptomatic severe AS,and the impact on postoperative left ventricular reverse remodeling.Methods:Patients with symptomatic severe AS who underwent TAVR surgery in the Department of Cardiovascular Medicine of the Second Affiliated Hospital of Nanchang University from January 2018 to October 2022 were selected.Patients were divided into the New LBBB group and the No LBBB group,according to whether the electrocardiogram indicated complete LBBB after the operation and continued until discharge.The preoperative baseline clinical characteristics,ultrasound and CTA parameters and intraoperative data between the two groups were compared.The risk factors of new LBBB after TAVR were analyzed by multivariate logistic regression,and the Receiver Operating Characteristic curve analysis.Patients from April 2019 to April 2022 were further selected to collect follow-up data of cardiac color Doppler ultrasound,and the changes of relevant parameters were statistically analyzed to explore the influence on left ventricular inverse remodeling.Results:A total of 91 patients were included,with the average age of patients was71.8±7.2 years old,male accounted for 59.3%,bivalent aortic valve accounted for52.7%.In the perioperative period,a total of 35 patients developed new LBBB after TAVR,but 3 patients recovered spontaneously,and 32 patients continued until the last ECG before discharge.The incidence of new-onset LBBB was 35.2%.The results of Multivariate logistic regression analysis showed that aortic angulation(OR: 1.084,95%CI: 1.013-1.161,P=0.020)and implant depth of prosthetic valve(OR: 1.287,95%CI: 1.085-1.512,P=0.003)were independent risk factors for new-onset LBBB after TAVR.ROC curve analysis showed that implantation depth(AUC=0.700,95%CI 0.591-0.809,P =0.002)and aortic angulation(AUC=0.664,95%CI 0.551-0.776,P =0.002)were predictive values for the occurrence of LBBB after TAVR.There were significant differences in baseline left ventricular mass index(LVMI)and left ventricular end-diastolic diameter(LVEDD)between the two groups,but no significant differences were found between the two groups at postoperative follow-up periods.From 3 to 6 months after TAVR,the LVEDD,Inter ventricular septal thickness(IVST),left ventricular ejection fraction(LVEF)and LVMI were significantly improved in the No LBBB group,but not in the New LBBB group.From 9 to 15 months after TAVR,there was no significant change in LVEDD and IVST in patients with New LBBB compared with those before TAVR,and a greater proportion of patients with worsening LVEF occurred(50% vs.13.6%,P < 0.05).Conclusion(1)Aortic angulation(AA)and implantation depth of artificial valve stent were independent risk factors for the occurrence of new-onset LBBB after TAVR,which had certain reference value for the prediction of postoperative new-onset LBBB.(2)In patients with severe aortic stenosis,the treatment of TAVR can improve left ventricular function and regress left ventricular hypertrophy by reducing cardiac afterload,and achieve reverse remodeling.Beneficial retro-remodeling occurred in both groups after TAVR,while the new LBBB resulted in asynchronous contraction of intra-and inter-ventricular,thereby reducing part of the benefits.