The Influence of Transcatheter Aortic Valve Replacement on Left Atrial Mechanics: A Systematic Review and Meta-Analysis

Background The morphology and function of the left atrium (LA) are intimately tied to left ventricular loading conditions. Data pertaining to the effect of transcatheter aortic valve replacement (TAVR) on LA function and geometry are scarce. Objectives To quantify associations between TAVR and LA remodelling by pooling available data from published observational studies. Methods A systematic review and meta-analysis were performed. Eligible studies needed to report serial LA STE data, before and after TAVR. Other outcome data included LA area and indexed volume (LAVi) and standard chamber measurements. Outcomes were stratified by timing of follow-up echocardiography: early (<6mo) or late (≥6mo). Results Twelve studies were included, comprising 1,066 patients. The mean overall reduction in LAVi was 2.72mls/m[2][1] following TAVI (95% CI 1.37-4.06, p <0.01, low heterogeneity: I[2][1] = 0%). LA reservoir function improved overall by a mean difference of 3.71% (95% CI 1.82-5.6, p<0.01), though there was significant heterogeneity within the pooled studies (I[2][1] = 87.3%). Significant improvement in reservoir strain was seen in both early follow up (MD 3.1%, p<0.01) and late follow up studies (MD 4.48%, p=0.03), but heterogeneity remained high (I[2][1] = 65.23% and 94.4%, respectively). Six studies reported change in LA booster/contractile function, which recovered in the early follow-up studies (MD 2.26, p<0.01), but not in the late group (MD 1.41, p=0.05). Pooled improvement in LA booster function was 1.96% (95% CI 1.11-2.8, p<0.01, low heterogeneity: I[2][1] = 0%). Conclusion The afterload reduction afforded by TAVR is associated with significant haemodynamic and morphological up-stream LA changes. Condensed Abstract The morphology and function of the left atrium (LA) are intimately tied to left ventricular loading conditions. LA function, measured with speckle-tracking echocardiography (STE), has been demonstrated to provide independent prognostic information for a range of cardiomyopathic states and valvular diseases. We sought to better understand the effect of transcatheter aortic valve replacement (TAVR) on LA function and geometry by performing a systematic review and meta-analysis. Key findings are that, following TAVR, the left atrium negatively remodels (reduces in size), and this is associated with improved distensibility, as quantified by an improvement in reservoir function. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial NA ### Funding Statement No external funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: NA I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data are available upon reasonable request. * AVA : aortic valve area BEV : balloon expandable valve LA : Left atrium LAVi : Left atrial volume index LV : Left ventricle LVEF : left ventricular ejection fraction SEV : self-expanding valve STE : speckle tracking echocardiography TAVR : transcatheter aortic valve replacement [1]: #ref-2