Functional MR in Ischemic Cardiomyopathy

描述(由申请人提供)： 功能性二尖瓣返流(MR)是缺血性心脏病的常见并发症。两项大型临床试验证实，功能性磁共振对心脏病发作后的存活率有不良影响。然而，关于心力衰竭的研究很少，主要局限于非缺血性心肌病患者。最近的动物研究挑战了传统的观点，即功能性MR是二尖瓣环扩张的结果，相反，功能性MR是由于左室壁向外扩张(即左室重构)而导致的叶拴系。这对纠正功能性MR的正确手术方法具有重要意义。到目前为止，还没有大型前瞻性研究探讨功能性MR在缺血性心肌病中的作用机制(S)，也没有探讨机制与预后之间的相互作用。这是一个关键的知识差距，因为1)70%的心力衰竭病例是由缺血性心脏病引起的，2)功能性MR发生在大约60%的缺血性心肌病患者中。这项建议旨在通过在一项针对缺血性心肌病患者的大型临床试验中，通过经食道超声心动图确定功能性MR的机制(S)来填补这些空白。将实现以下具体目标： 目的1：明确功能性MR在缺血性心肌病中的作用机制(S)。目的2：明确治疗对功能性MRAim发生机制和严重程度的影响。3：评价功能性MR对缺血性心肌病预后的影响。目的4：评价存活心肌对功能性MR的影响及其治疗反应。 我们建议将实现这些目标作为缺血性心力衰竭外科治疗(STICH)试验的辅助研究。STICH试验将在2,800名缺血性心肌病患者中比较外科血管重建术和药物治疗心力衰竭的疗效，因此为研究功能性MR的机制(S)提供了一个独特的机会。尽管已知TEE可用于评估MR的机制和严重程度，但STICH目前未纳入TEE。

DESCRIPTION (provided by applicant): Functional mitral regurgitation (MR) is a common complication of ischemic heart disease. Two large clinical trials confirmed an adverse effect of functional MR on survival after a heart attack. However, studies in heart failure are small and mainly limited to patients with nonischemic cardiomyopathy. Recent animal studies have challenged the traditional concept that functional MR is a consequence of mitral annular dilation, instead suggesting that functional MR is due to leaflet tethering by outward expansion of the left ventricular wall (i.e. LV remodeling). This has critical implications regarding the correct surgical approach to correcting functional MR. TO date, no large prospective studies have examined the mechanism(s) of functional MR in ischemic cardiomyopathy, nor has the interaction between mechanism and prognosis been explored. This is a crucial knowledge gap because 1) 70% of heart failure cases are caused by ischemic heart disease, and 2) functional MR occurs in around 60% of patients with ischemic cardiomyopathy. This proposal aims to fill these gaps by defining the mechanism(s) of functional MR by transesophageal echocardiography in a large clinical trial of patients with ischemic cardiomyopathy. The following specific aims will be addressed: Aim 1: To define the mechanism(s) of functional MR in ischemic cardiomyopathyAim 2: To define the effect of therapy on mechanism and severity of functional MRAim 3: To evaluate the effect of functional MR on prognosis is ischemic cardiomyopathyAim 4: To evaluate the effect of myocardial viability on functional MR and its response to treatment We propose to accomplish these aims as a ancillary study to the Surgical Treatment of Ischemic Heart Failure (STICH) Trial. The STICH Trial will compare surgical revascularization versus medical therapy for treatment of heart failure in 2800 patients with ischemic cardiomyopathy, and therefore affords a unique opportunity to investigate the mechanism(s) of functional MR. Despite its known clinical utility of assessing the mechanism and severity of MR, TEE is not currently included in STICH.