Kradangnga Krishaporn, Monnet Eric
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA.
Department of Veterinary Surgery, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
Heart Surg Forum. 2020 Feb 10;23(1):E010-E017. doi: 10.1532/hsf.2725.
High recurrent functional ischemic mitral regurgitation (FIMR) has been observed after annuloplasty. Since annuloplasty alone could not prevent late recurrent FIMR or improve the survival rate after CABG, adjunctive subvalvular opt for better treatment tailored for each individual patient.
Ex vivo ovine heart models with annular dilatation and PPM displacement were used for analysis of mitral regurgitation (MR) flow, left ventricular and annular geometry after treatment by mitral annular reduction alone (MA, nMA = 12) or combined with epicardial PPM repositioning (MA+PPM, nMA+PPM=13).
MR significantly was reduced from baseline in both the MA (P = .03) and MA+PPM (P = .02) groups, but was not significantly different between the groups. The septo-lateral mitral annular distance decreased after applying both methods (MA group P = .005; MA+PPM group P = .05). The tethering α angle of the APM in the frontal plane significantly increased from baseline in the MA+PPM group (P = .027). Furthermore, the MA+PPM group had a larger APM and PPM α angle in the frontal plane compared with the MA group after reducing the MR (P = .04). There were no statistically significant changes in tethering angles found in the MA group compared with baseline. MR reduction correlated with percentage decrease of septo-lateral mitral annular distance (rs = 0.51, P = .01), the percentage decrease of fibrosa-PPM distance (rs = 0.43, P = .03), and the percentage increase of the PPM anterior displacement (rs = -0.41, P = .04).
The decreased tethered angle of the PPM referred to the annulus, and the decreased interpapillary muscles distance suggested the PPM was repositioned inward and toward the septal annulus by the epicardial pushing pad. Epicardial repositioning of the PPM adjunct with mitral annular reduction facilitated leaflet coaptation without the risk of overlying restriction of the mitral annular orifice.
在二尖瓣环成形术后已观察到较高的复发性功能性缺血性二尖瓣反流（FIMR）。由于单纯的二尖瓣环成形术无法预防晚期复发性FIMR或提高冠状动脉旁路移植术（CABG）后的生存率，因此对于瓣下结构的处理应选择更适合每个患者的个体化治疗。
使用具有瓣环扩张和后乳头肌（PPM）移位的体外羊心模型，分析单纯二尖瓣环缩小术（MA，nMA = 12）或联合心外膜PPM重新定位（MA + PPM，nMA + PPM = 13）治疗后的二尖瓣反流（MR）血流、左心室和瓣环几何形状。
MA组（P = 0.03）和MA + PPM组（P = 0.02）的MR均较基线显著降低，但两组之间无显著差异。应用两种方法后，二尖瓣间隔-外侧瓣环距离均减小（MA组P = 0.005；MA + PPM组P = 0.05）。MA + PPM组额面APM的牵拉α角较基线显著增加（P = 0.027）。此外，在降低MR后，MA + PPM组在额面的APM和PPMα角较MA组更大（P = 0.04）。与基线相比，MA组的牵拉角度无统计学显著变化。MR降低与二尖瓣间隔-外侧瓣环距离的百分比降低（rs = 表0.51，P = 0.01）、纤维层-PPM距离的百分比降低（rs = 0.43，P = 0.03）以及PPM向前移位的百分比增加（rs = -0.41，P = 0.04）相关。
PPM相对于瓣环的牵拉角度减小，以及乳头肌间距离减小，提示心外膜推压垫使PPM向内并朝向间隔瓣环重新定位。心外膜PPM重新定位联合二尖瓣环缩小术有助于瓣叶贴合，而无二尖瓣瓣环口过度受限的风险。
