Srichai Monvadi B, Grimm Richard A, Stillman Arthur E, Gillinov A Marc, Rodriguez L Leonardo, Lieber Michael L, Lara Abigail, Weaver Joan A, McCarthy Patrick M, White Richard D
Department of Radiology, Cleveland Clinic Foundation, Cleveland, Ohio, USA.
Ann Thorac Surg. 2005 Jul;80(1):170-8. doi: 10.1016/j.athoracsur.2005.01.068.
Mitral regurgitation (MR) is a common complication of ischemic heart disease, and its presence portends adverse outcomes. As the exact mechanisms of ischemic MR are not well defined, we characterized left ventricular global geometry, regional function, and regional myocardial scarring, in addition to mitral valve apparatus geometry, using magnetic resonance imaging (MRI) of ischemic heart disease patients with left ventricular dysfunction and varying degrees of ischemic MR.
Sixty patients with varying degrees of MR (none, mild, moderate, and severe) determined by echocardiography and referred for MRI assessment of ischemic heart disease were included. Left ventricular geometric, functional, and scar measurements in addition to mitral valve geometric measurements were evaluated.
Clinical characteristics found to be significant predictors of degree of MR included severity of coronary artery disease (p < 0.05), completeness of myocardial perfusion (p < 0.005), and average systolic blood pressure (p < 0.05). Mitral systolic tenting area (p < 0.0001) in a statistical model with scarring of the anterior-lateral region (p < 0.05) proved to be the most powerful predictor of MR severity (r2 = 0.31). Mitral annular dilatation in the anterior-posterior direction (p < 0.0001) and diminished LV systolic function (p < 0.005) were important determinants of mitral systolic tenting area (r2 = 0.57).
Mitral tenting in combination with regional left ventricular myocardial scarring are important mechanisms to the development of ischemic MR. Surgical annuloplasty addresses mitral tenting, but has little impact on the effect of regional scarring. Moderate-to-severe ischemic MR develops in patients with regional scarring of the anterior-lateral and inferior-posterior regions, and new surgical developments should take this into account.
二尖瓣反流（MR）是缺血性心脏病的常见并发症，其存在预示着不良后果。由于缺血性MR的确切机制尚未明确，我们使用磁共振成像（MRI）对患有左心室功能障碍和不同程度缺血性MR的缺血性心脏病患者进行了研究，以确定左心室整体几何形状、区域功能和区域心肌瘢痕形成，以及二尖瓣装置的几何形状。
纳入60例经超声心动图确定有不同程度MR（无、轻度、中度和重度）并转诊进行缺血性心脏病MRI评估的患者。评估了左心室几何形状、功能和瘢痕测量，以及二尖瓣几何测量。
发现临床特征是MR程度的重要预测指标，包括冠状动脉疾病的严重程度（p < 0.05）、心肌灌注的完整性（p < 0.005）和平均收缩压（p < 0.05）。在一个包含前外侧区域瘢痕形成（p < 0.05）的统计模型中，二尖瓣收缩期帐篷面积（p < 0.0001）被证明是MR严重程度的最有力预测指标（r2 = 0.31）。前后方向的二尖瓣环扩张（p < 0.0001）和左心室收缩功能减弱（p < 0.005）是二尖瓣收缩期帐篷面积的重要决定因素（r2 = 0.57）。
二尖瓣帐篷形成与区域左心室心肌瘢痕形成相结合是缺血性MR发生发展的重要机制。手术瓣环成形术可解决二尖瓣帐篷形成问题，但对区域瘢痕形成的影响很小。中重度缺血性MR发生在前外侧和下后区域有区域瘢痕形成的患者中，新的手术进展应考虑到这一点。
