Echocardiography to Predict Recurrent IMR After Surgical Mitral Valve Replacement

描述(由申请人提供)：缺血性二尖瓣反流(IMR)影响160至280万美国人，并增加死亡率，即使是轻微的。在IMR的严重程度和存活率下降之间有很强的分级关系。在IMR中，瓣膜关闭不全是由于叶系留和环状扩张的不同组合所致。二尖瓣环过小的二尖瓣成形术已成为首选的治疗方法；然而，尽管二尖瓣成形术有效地解决了二尖瓣环扩张的问题，但它并没有改善，而且可能会加剧小叶拴系。MV修复与术后6个月内显着IMR(e2+)30%的复发率有关。这种高复发率大大限制了MV修复治疗IMR的疗效。在更好地了解和消除复发性二尖瓣反流的混淆现象之前，很可能不可能实现标准化和可靠有效的外科治疗方法。根据复发性IMR的术前影像危险分层指导的针对患者的治疗方法，往往是实现这一重要目标的最佳手段。拟议项目的目的是开发这样一种风险分层工具。这一建议的中心假设是，修复前二尖瓣叶拴系的程度决定了IMR环状成形术后二尖瓣返流的复发程度。我们进一步假设，术前超声心动图可以有效地量化肺叶系留，三维超声心动图(3DE)在预测IMR复发程度方面优于标准二维超声心动图(2DE)。这项拟议的研究旨在开发超声心动图技术，在手术前预测单个患者在手术后第一年内可预期的IMR复发程度。拟议研究的预期结果将使外科医生能够确定哪些IMR患者最适合标准的MV修复(即瓣环成形术)，哪些患者更适合瓣膜置换术。这种方法将限制复发的IMR，同时最大限度地增加患者谁实现了MV修复的好处。这两个结果都将改善临床结果。我们建议在5年内在三个大容量心脏外科中心招募378名患者。术中2DE和3DE参数将与术后6个月和12个月的IMR复发程度相关。

DESCRIPTION (provided by applicant): Ischemic mitral regurgitation (IMR) affects 1.6 to 2.8 million Americans and increases mortality even when mild. There is a strong graded relationship between the severity of IMR and reduced survival. Valve incompetence in IMR occurs due to a variable combination of leaflet tethering and annular dilation. Mitral valve (MV) repair with undersized annuloplasty rings has become the preferred treatment; however, while annuloplasty effectively addresses annular dilatation, it does not improve and may exacerbate leaflet tethering. MV repair is associated with a 30% recurrence rate of significant IMR (e2+) within 6 months after surgery. This high recurrence rate significantly limits the efficacy of MV repair for IMR. It is likely that a standardized and reliably efficacious surgical therapeutic approach to IMR will not be achievable until the confounding phenomena of recurrent mitral regurgitation can be better understood and subsequently neutralized. A patient-specific approach to treatment, guided by preoperative imaging-based risk stratification for recurrent IMR, is apt to be the best means for achieving this important goal. It is the intent of the proposed project to develop such a tool for risk stratification. The central hypothesis of this proposal is that the degree of pre-repair mitral leaflet tethering determines the degree of recurrent mitral regurgitation after ring annuloplasty for IMR. We further hypothesize that leaflet tethering can be effectively quantified preoperatively by echocardiography and that three-dimensional echocardiography (3DE) is superior to standard two-dimensional echocardiography (2DE) for predicting the degree of recurrent IMR. The proposed study seeks to develop echocardiographic techniques to predict, preoperatively, the degree of recurrent IMR that can be expected for an individual patient within the first year after surgery. The anticipated results of the proposed study will allow surgeons to determine which IMR patients are best treated with standard MV repair (i.e. ring annuloplasty) and which are better served by valve replacement. Such an approach will limit recurrent IMR and simultaneously maximize the number of patients who realize the benefits of MV repair. Both results will improve clinical outcomes. We propose to enroll 378 patients at three high-volume cardiac surgical centers over a 5 year period. Intraoperative 2DE and 3DE parameters will be correlated with the degree of recurrent IMR at 6 and 12 months after surgery.