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160万至280万美国人，即使轻微也会增加死亡率。在IMR的严重程度和生存率降低之间有很强的分级关系。IMR的瓣膜功能不全是由于小叶栓系和环扩张的不同组合造成的。小环成形术修复二尖瓣已成为首选的治疗方法；然而，虽然成形术有效地解决了环扩张，但它不能改善并可能加剧小叶栓系。MV修复与术后6个月内显著IMR （e2+）复发率30%相关。这种高复发率明显限制了中压修复对IMR的疗效。在二尖瓣返流的混淆现象得到更好的理解和随后的消除之前，很可能无法实现标准化和可靠有效的手术治疗方法。在术前基于影像学的复发性IMR风险分层的指导下，针对患者的治疗方法可能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。该建议的中心假设是修复前二尖瓣小叶栓系的程度决定了IMR环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小叶栓系，并且三维超声心动图（3DE）优于标准二维超声心动图（2DE）预测复发性IMR的程度。该研究旨在发展超声心动图技术，以预测术前单个患者术后一年内复发性IMR的程度。拟议研究的预期结果将允许外科医生确定哪些IMR患者最好采用标准的中压修复（即环成形术），哪些患者最好采用瓣膜置换术。这种方法将限制复发性IMR，同时最大限度地使患者认识到中压修复的好处。这两个结果都将改善临床结果。我们建议在3个大容量心脏外科中心招募378名患者，为期5年。术中2DE和3DE参数与术后6个月和12个月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.