Echocardiography to Predict Recurrent IMR After Surgical Mitral Valve Replacement

描述（由申请人提供）：缺血性二尖瓣返流（IMR）影响160万至280万美国人，即使在轻度时也会增加死亡率。IMR的严重程度和生存率降低之间存在很强的分级关系。IMR中的瓣膜关闭不全是由于瓣叶栓系和瓣环扩张的可变组合而发生的。使用尺寸过小的瓣膜成形环进行二尖瓣（MV）修复已成为首选治疗;然而，虽然瓣膜成形术有效地解决了瓣环扩张，但它不会改善瓣叶束缚，并可能加剧瓣叶束缚。二尖瓣修复术后6个月内显著IMR（e2+）的复发率为30%。这种高复发率显著限制了二尖瓣修复术治疗IMR的疗效。在能够更好地理解并随后消除复发性二尖瓣返流的混淆现象之前，可能无法实现标准化且可靠有效的IMR手术治疗方法。根据术前影像学对复发性IMR进行风险分层，指导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，修复前二尖瓣瓣叶栓系的程度决定了环成形术治疗IMR后二尖瓣返流的复发程度。我们进一步假设，术前超声心动图可有效量化瓣叶栓系，三维超声心动图（3DE）在预测复发性IMR程度方面上级标准二维超声心动图（2DE）。这项研究旨在开发超声心动图技术，以预测，术前，复发IMR的程度，可以预期在手术后的第一年内的个别患者。拟议研究的预期结果将使外科医生能够确定哪些IMR患者最适合采用标准MV修复术（即瓣环成形术）治疗，哪些患者更适合采用瓣膜置换术。这种方法将限制复发性IMR，同时最大限度地增加实现MV修复受益的患者数量。这两个结果将改善临床结果。我们计划在3个高容量心脏外科中心招募378例患者，为期5年。术中2DE和3DE参数将与术后6个月和12个月复发IMR的程度相关。

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.