Predicting the outcome of transcatheter mitral valve implantation using image-based computational models

BackgroundThe appropriate placement and size selection of mitral prostheses in transcatheter mitral valve implantation (TMVI) is critical, as encroachment on the left ventricular outflow tract (LVOT) may lead to flow obstruction. Recent advances in computed tomography (CT) can be employed for pre-procedural planning of mitral prosthetic valve placement. This study aims to develop patient-specific computational fluid dynamics models of the left ventricle (LV) in the presence of a mitral valve prosthesis to investigate blood flow and LVOT pressure gradient during systole.MethodsPatient-specific computational fluid dynamics simulations of TMVI with varied cardiac anatomy and insertion angles were performed (n = 30). Wide-volume full cycle cardiovascular CT images prior to TMVI were used as source anatomical data (n = 6 patients). Blood movement was governed by Navier-Stokes equations and the LV endocardial wall deformation was derived from each patient's CT images.ResultsThe computed pressure gradients in the presence of the mitral prosthesis compared well with clinically measured gradients. Analysis of the effects of prosthetic valve angulation, aorto-mitral annular angle, ejection fraction, LV size and new LVOT area (neo-LVOT) after TMVI in silico revealed that the neo-LVOT area (p < 0.001) was the most significant factor affecting LVOT pressure gradient. Angulation of the mitral valve can substantially mitigate LVOT gradient.ConclusionsComputational fluid dynamics simulation is a promising method to aid in pre-TMVI planning and understanding the factors underlying LVOT obstruction.     

Highlights of the 15th annual scientific meeting of the Society of Cardiovascular Computed Tomography

The 15th Society of Cardiovascular Computed Tomography (SCCT) annual scientific meeting (ASM) welcomed 770 digital attendees from 44 countries, over 2 days, with a program that included 30 sessions across three simultaneously streaming channels, 10 exhibitors and a diverse range of scientific abstracts. In addition, #SCCT2020 generated >5900 tweets from nearly 700 engaged social media participants resulting in an estimated 38 million digital impressions and becoming #1 trending medical meeting in social media in the world during the meeting time period. This article summarizes the many themes and topics of presentation and discussion in this meeting, and the many technical advances that are likely to impact future clinical practice in cardiovascular computed tomography.     

应用计算机流体力学技术评估症状性颅内动脉狭窄患者卒中复发风险的研究

目的 评估基于计算机流体力学（computational fluid dynamics，CFD）技术的无创血流动力学参数与缺血性卒中复发之间的关系。      

Editor's Introduction: 2017 Rumelhart Prize Issue Honoring Lila R. Gleitman

This is the Editor's introduction to the Special Issue of TopiCS in honor of Lila R. Gleitman's receipt of the 2017 David E. Rumelhart Prize. The introduction gives an overview of Gleitman's intellectual history and scientific contributions, and it briefly reviews each of the contributions to the issue.     

膝骨关节炎中医药系统生物学研究述评＊

膝骨关节炎（Knee Osteoarthritis， KOA）属于临床难治性疾病，其高发病率、高致残性给国民健康、社会发展造成了沉重的负担。在这种不利局面下，中医药在KOA的临床防治上发挥了巨大的作用，其根据“辨证施治”理念的指导对患者采用个体化治疗往往能够取得良好的临床疗效 。然而中医学在传统认知上作为经验医学的集成，现有的KOA中医药基础研究结果尚未完全阐明其客观化、现代化的属性，阻碍了中医药防治KOA科学内涵的揭示以及全面、系统的临床研究的开展和新药研发，如何开展完善、合理、可行的基础研究以进行KOA中医药客观化和现代化探索成为研究者不得不解决的重大难题。随着系统生物学知识结构和研究手段的完善与更新，其与中医药的结合已经成为阐释并创新中医药理论内核、突破中医药研究瓶颈的重要方法。本文通过总结、分析目前KOA中医药基础研究的现状与不足，突出系统生物学在目前KOA中医药研究中的关键作用及应用趋势，以期为今后KOA的中医药研究和发展提供新的思路与对策。     

Disruption of RHOA-ROCK Signaling Results in Atrioventricular Block and Disturbed Development of the Putative Atrioventricular Node

The RHOA-ROCK signaling pathway is involved in numerous developmental processes, including cell proliferation, differentiation and migration. RHOA is expressed in the atrioventricular node (AVN) and altered expression of RHOA results in atrioventricular (AV) conduction disorders in mice. The current study aims to detect functional AVN disorders after disturbing RHOA-ROCK signaling in chicken embryos. RHOA-ROCK signaling was inhibited chemically by using the Rho-kinase inhibitor compound Y-27632 in avian embryos (20 experimental and 29 control embryos). Morphological examination of control embryos show a myocardial sinus venosus to atrioventricular canal continuity, contributing to the transitional zone of the AVN. ROCK inhibited embryos revealed lateralization and diminished myocardial sinus venosus to atrioventricular canal continuity and at the severe end of the phenotype hypoplasia of the AVN region. Ex ovo micro-electrode recordings showed an AV conduction delay in all treated embryos as well as cases with first, second (Wenkebach and Mobitz type) and third-degree AV block which could be explained by the spectrum of severity of the morphological phenotype. Laser capture microdissection and subsequent qPCR of tissue collected from this region revealed disturbed expression of HCN1, ISL1, and SHOX2. We conclude that RHOA-ROCK signaling is essential for normal morphological development of the myocardial continuity between the sinus venosus and AVN, contributing to the transitional zone, and possibly the compact AVN region. Disturbing the RHOA-ROCK signaling pathway results in AV conduction disturbances including AV block. The RHOA-ROCK inhibition model can be used to further study the pathophysiology and therapeutic strategies for AV block. Anat Rec, 302:83–92, 2019. © 2018 Wiley Periodicals, Inc.