3D echocardiography to evaluate ischemic mitral regurgitation in humans.

描述(申请人提供)：缺血性二尖瓣返流(IMR)是心肌梗死的常见并发症，与较差的长期存活率有关。无论治疗方法如何，发生IMR的患者患充血性心力衰竭(CHF)的风险显著增加，冠状动脉血管重建术后的预后也明显更差。IMR二尖瓣修复术后的结果一直令人失望，有经验的中心报告说，在修复后6个月，失败率高达50%。最近报道的成像数据表明，修复前后的IMR与二尖瓣环的扩张和平坦有关，从而阻止了正常的瓣膜对接和允许返流的血流。二尖瓣成形术失败的具体原因以及梗死性二尖瓣环重构对二尖瓣环形态的影响至今尚未完全研究。我们的目的是在IMR病例中评估二尖瓣成形环形状对人类二尖瓣力学和二尖瓣修复耐久性的影响，并表明使用准确再现自然二尖瓣环鞍形的二尖瓣成形环可以提高二尖瓣修复耐久性。为了实现这些目标，我们将利用一种新技术：高分辨率、定量、三维超声心动图，对人体二尖瓣进行全面成像。这项新兴技术将使我们能够量化导致IMR发展的三种几何病理：环状扩张、环状扁平和瓣叶栓系，从而预测哪些患者将从二尖瓣修复和置换中受益。我们将利用实时三维超声心动图(RT-3DE)建立IMR的定量参数。我们的目标是用以前的成像技术不可能的空间分辨率来描述IMR的环状重塑的本质。此外，我们将评估环状成形术形状对修复耐久性的影响。在人类中，IMR将使用标准的菲亚特环成形术环或反映自然环状形状的鞍环进行修复。两组患者均于术后即刻、术后12个月、术后24个月分别测量RT：-3DE值，评价二尖瓣病变程度及二尖瓣病变特征。尽管进行了最好的内科和外科治疗，但脑梗塞所致心力衰竭的五年存活率接近50%，由此给医疗保健系统带来的压力是惊人的。该项目的主要目标是开发一种临床上相关的、非侵入性的、强大的成像手段，用于在IMR病例中询问二尖瓣，并利用这项技术来描述临床上有效的相关手术治疗。

DESCRIPTION (provided by applicant): Ischemic mitral regurgitation (IMR) is a frequent complication of myocardial infarction that is associated with poor long-term survival. Irrespective of treatment, patients who develop IMR are at significantly increased risk for congestive heart failure (CHF) and have markedly worse prognoses following coronary revascularization. Results following mitral valve repair for IMR have been disappointing, and experienced centers report failure rates as high as 50% at 6 months post-repair. Recently reported imaging data suggests that pre- and post-repair IMR are associated with dilatation and flattening of the mitral valve annulus, preventing normal valve apposition and allowing regurgitant blood flow. The detailed basis for the failure of mitral valve repair and the effect of infarction-induced remodeling on mitral annular shape has been incompletely studied to date. Our aim is to assess the of impact of annuloplasty ring shape on human mitral valve mechanics and mitral valve repair durability in cases of IMR and show that the use of an annuloplasty ring that accurately reproduces the saddle shape of the native mitral annulus increases repair durability. To accomplish these goals we will utilize a novel technology: high-resolution, quantitative, 3-dimensiorial echocardiography for comprehensive imaging of the human mitral valve. This emerging technology will allow us to quantify the three geometric pathologies that contribute to the development of IMR: annular dilation, annular flattening, and leaflet tethering, and, therefore, predict which patients will benefit from mitral valve repair versus replacement. We will utilize real-time three-dimensional echocardiography (rt-3DE) to establish quantitative parameters of IMR. We aim to characterize the nature of annular remodeling in IMR with a spatial resolution not possible with previous imaging technology. In addition, we will assess the effects of ring annuloplasty shape on repair durability. IMR will be repaired in humans with either a standard fiat annuloplasty ring or a saddle ring that reflects native annular shape. For both valve groups, rt:-3DEparameters measured pre- and post-repair will be used to assess the degree of MR and characteristics of the mitral valve immediately, at 12 months, and at 24 months post-repair. The five-year survival for infarction-induced CHF approaches 50% despite best medical and surgical therapy, and the resultant strain on the healthcare system is staggering. The primary objective of this project is to develop a clinically relevant, noninvasive, powerful imaging modality for interrogating the mitral valve in cases of IMR, and to utilize this technique to delineate clinically effective, relevant surgical therapy.