Benjamin Mina M, Smith Robert L, Grayburn Paul A
Department of Internal Medicine, Baylor University Medical Center, The Heart Hospital Baylor Plano and Baylor Heart and Vascular Hospital, Dallas, TX, USA.
Curr Cardiol Rep. 2014 Aug;16(8):517. doi: 10.1007/s11886-014-0517-0.
Functional mitral regurgitation (FMR) occurs when normal or nearly normal mitral leaflets are prevented from proper coaptation by underlying left ventricular (LV) dysfunction, mitral annular dilation, or both. FMR is associated with an adverse prognosis in nonischemic or ischemic LV dysfunction. Multiple studies have confirmed that even mild FMR portends a worse prognosis, and that the risk of FMR is independent of LV volumes and other clinical risk factors. FMR can be difficult to quantitate echocardiographically because it is load dependent and can vary considerably from exam to exam. There is a systematic tendency to underestimate FMR severity by echocardiography because the regurgitant orifice in FMR is typically elliptical, but the formula for calculating regurgitant orifice area assumes circular geometry. Treatment of FMR begins with guideline-directed medical therapy (GDMT) for LV dysfunction and heart failure, including cardiac resynchronization, if indicated. Revascularization should be considered for ischemic FMR, when indicated. Finally, mitral valve surgery should be considered in patients undergoing CABG in whom moderate or greater FMR is present, and also when severe symptomatic FMR persists despite optimal GDMT and revascularization. Percutaneous options for treatment of FMR are in development but are not currently approved in the US.
功能性二尖瓣反流（FMR）是指在左心室（LV）功能障碍、二尖瓣环扩张或两者共同作用下，正常或接近正常的二尖瓣叶无法正常对合时发生的情况。FMR与非缺血性或缺血性LV功能障碍的不良预后相关。多项研究证实，即使是轻度FMR也预示着更差的预后，且FMR的风险独立于LV容积和其他临床风险因素。FMR通过超声心动图很难进行定量，因为它依赖于负荷，且每次检查结果可能有很大差异。超声心动图存在系统性低估FMR严重程度的倾向，因为FMR中的反流口通常是椭圆形的，但计算反流口面积的公式假定为圆形几何形状。FMR的治疗首先是针对LV功能障碍和心力衰竭的指南指导药物治疗（GDMT），如有指征可包括心脏再同步治疗。对于缺血性FMR，如有指征应考虑血运重建。最后，对于接受冠状动脉旁路移植术（CABG）且存在中度或更严重FMR的患者，以及尽管进行了最佳的GDMT和血运重建但仍存在严重症状性FMR的患者，应考虑二尖瓣手术。FMR的经皮治疗方法正在研发中，但目前在美国尚未获批。
