Koga Shugo, Okazaki Yukio, Kataoka Hiromi, Ikeda Kazuyuki, Furukawa Kojiro, Ohtsubo Satoshi, Itoh Tsuyoshi
Department of Thoracic and Cardiovascular Surgery, Saga University Hospital, Saga, Japan.
J Heart Valve Dis. 2007 Nov;16(6):602-7.
During off-pump coronary artery bypass grafting (CABG), mitral regurgitation (MR) has been experienced in relation to the procedures. The study aim was to evaluate the mitral valve configuration, with particular focus on annular behavior, during off-pump CABG, using cardiac endoscopy and digital 3-D ultrasound sonomicrometry.
Following implantation of six crystals of the digital 3-D ultrasound sonomicrometer around the mitral annulus, and two crystals on the epicardial base of the papillary muscles, off-pump CABG was simulated in seven beagle dogs. The heart was perfused with pellucid Krebs-Henseleit solution in situ, with controlled left ventricular end-diastolic pressure (LVEDP). The behaviors of the mitral annulus and leaflets were then observed endoscopically with only cardiac displacement, 15 min occlusion of the left anterior descending artery (LAD), or 15 min occlusion of the left circumflex artery (LCx) with cardiac displacement. Dimensions between the crystals were also recorded using digital 3-D ultrasound sonomicrometry.
With only cardiac displacement, no MR was observed endoscopically, and no major changes occurred in annular configuration when coronary perfusion was maintained. In one dog, MR was observed only from the anterolateral site after LAD occlusion. MR from the posteromedial site was observed by occlusion of the LCx in all cases, with significant (p < 0.01) enlargement of the mitral annular dimensions.
Cardiac displacement alone did not cause MR if coronary perfusion was maintained. Occlusion of the LAD rarely caused MR from the anterolateral site, whereas occlusion of the LCx normally caused MR from the posteromedial site; the posteromedial annulus was enlarged, even when the LVEDP was controlled.
在非体外循环冠状动脉旁路移植术（CABG）过程中，二尖瓣反流（MR）与手术操作相关。本研究旨在使用心脏内镜和数字三维超声心动图测量法，评估非体外循环CABG期间的二尖瓣结构，尤其关注瓣环的变化情况。
在七只比格犬身上模拟非体外循环CABG，在二尖瓣环周围植入六颗数字三维超声心动图测量仪的晶体，并在乳头肌的心外膜基部植入两颗晶体。在原位用透明的克雷布斯 - 亨塞尔特溶液灌注心脏，控制左心室舒张末期压力（LVEDP）。然后，仅观察心脏移位、左前降支动脉（LAD）闭塞15分钟或左旋支动脉（LCx）闭塞15分钟并伴有心脏移位时二尖瓣环和瓣叶的内镜表现。还使用数字三维超声心动图测量法记录晶体之间的距离。
仅心脏移位时，内镜未观察到MR，维持冠状动脉灌注时瓣环结构无重大变化。在一只犬中，LAD闭塞后仅在前外侧部位观察到MR。在所有情况下，LCx闭塞均观察到来自后内侧部位的MR，二尖瓣环尺寸显著增大（p < 0.01）。
如果维持冠状动脉灌注，仅心脏移位不会导致MR。LAD闭塞很少导致前外侧部位的MR，而LCx闭塞通常导致后内侧部位的MR；即使LVEDP得到控制，后内侧瓣环仍会扩大。
