The Effects of Percutaneous Mitral Balloon Valvuloplasty on the Left Atrial Appendage Function in Patients With Sinus Rhythm and Atrial Fibrillation

Introduction: Mitral stenosis (MS) causes structural and functional abnormalitiesof the left atrium (LA) and left atrial appendage (LAA), and studies show that LAA performance improves within a short time after percutaneous transvenous mitral commissurotomy (PTMC). This study aimed to investigate the effects of PTMC on leftatrial function by transesophageal echocardiography (TEE).Methods: We enrolled 56 patients with severe mitral stenosis (valve area less than1.5 CM2). All participants underwent mitral valvuloplasty; they also underwenttransesophageal echocardiography before and at least one month after PTMC.Results: Underlying heart rhythm was sinus rhythm (SR) in 28 patients and atrialfibrillation (AF) in remainder 28 cases. There was no significant change in the leftventricular ejection fraction (LVEF), left ventricular end diastolic dimension (LVEDD),or the left ventricular end systolic dimension (LVESD) before and after PTMC in bothgroups. However, both groups showed a significant decrease in the left atrial volumeindex (LAVI) following PTMC (P=0.032 in SR and P=0.015 in AF group). LAA ejectionfraction (LAAEF) and the LAA emptying velocity (LAAEV) were improved significantlyafter PTMC in both groups with SR and AF (P<0.001 for both).Conclusion: Percutaneous transvenous mitral commissurotomy improves left atrial appendage function in patients with mitral stenosis irrespective of the underlying heart rhythm

Validation of a prognostic multi-gene signature in high-risk neuroblastoma using the high throughput digital NanoString nCounter™ system

Microarray‐based molecular signatures have not been widely integrated into neuroblastoma diagnostic classification systems due to the complexities of the assay and requirement for high‐quality RNA. New digital technologies that accurately quantify gene expression using RNA isolated from formalin‐fixed paraffin embedded (FFPE) tissues are now available. In this study, we describe the first use of a high‐throughput digital system to assay the expression of genes in an “ultra‐high risk” microarray classifier in FFPE high‐risk neuroblastoma tumors. Customized probes corresponding to the 42 genes in a published multi‐gene neuroblastoma signature were hybridized to RNA isolated from 107 FFPE high‐risk neuroblastoma samples using the NanoString nCounter™ Analysis System. For classification of each patient, the Pearson's correlation coefficient was calculated between the standardized nCounter™ data and the molecular signature from the microarray data. We demonstrate that the nCounter™ 42‐gene panel sub‐stratified the high‐risk cohort into two subsets with statistically significantly different overall survival (p = 0.0027) and event‐free survival (p = 0.028). In contrast, none of the established prognostic risk markers (age, stage, tumor histology, MYCN status, and ploidy) were significantly associated with survival. We conclude that the nCounter™ System can reproducibly quantify expression levels of signature genes in FFPE tumor samples. Validation of this microarray signature in our high‐risk patient cohort using a completely different technology emphasizes the prognostic relevance of this classifier. Prospective studies testing the prognostic value of molecular signatures in high‐risk neuroblastoma patients using FFPE tumor samples and the nCounter™ System are warranted