Depré C, Vanoverschelde J L, Gerber B, Borgers M, Melin J A, Dion R
Division of Cardiology, University of Louvain Medical School, Brussels, Belgium.
J Thorac Cardiovasc Surg. 1997 Feb;113(2):371-8. doi: 10.1016/s0022-5223(97)70335-0.
Our objective was to investigate the influence of preoperative myocardial ultrastructure and metabolism on recovery of contractile function after coronary artery bypass grafting in patients with coronary artery disease and left ventricular dysfunction.
Dynamic positron emission tomography with 13N-ammonia and 18F-deoxyglucose was used to assess myocardial perfusion and glucose uptake in 53 patients scheduled for coronary revascularization because of coronary artery disease and left ventricular dysfunction. The degree of tissue fibrosis and the presence of potentially reversible alterations of cardiomyocytes (loss of myofilaments and accumulation of glycogen) were quantified from transmural biopsy specimens. These were harvested from the center of the dysfunctional area during the operation and analyzed with a light microscope. The recovery of contractile performance was assessed from the changes in left ventricular function at contrast ventriculography or echocardiography before and 6 months after the operation.
According to postoperative changes in regional wall motion, left ventricular function was considered to have improved in 34 patients, whereas dysfunction persisted in 19 patients. In patients with improved wall motion, ejection fraction rose by 12% and end-systolic volume decreased by 28%. By contrast, in patients with persistent dysfunction, ejection fraction decreased by 6% and end-systolic volume increased by 25%. Before revascularization, myocardium with reversible dysfunction displayed higher levels of absolute myocardial blood flow, higher myocardial glucose uptake, less tissue fibrosis, and more altered cardiomyocytes than myocardium with persistent dysfunction. Significant correlations were found between regional blood flow and the surface of the biopsy specimen covered by fibrosis, as well as between glucose uptake and the density of altered cardiomyocytes.
In patients with left ventricular ischemic dysfunction, the recovery of regional and global left ventricular function after surgical revascularization is associated with higher preoperative blood flow and glucose uptake, with less tissue fibrosis and a higher amount of viable cardiomyocytes in the dysfunctional area. The current study thus confirms the value of noninvasive preoperative metabolic imaging for identification of residual viable myocardium and for prediction of the functional outcome after revascularization.
我们的目的是研究术前心肌超微结构和代谢对冠心病合并左心室功能障碍患者冠状动脉搭桥术后收缩功能恢复的影响。
采用13N-氨和18F-脱氧葡萄糖动态正电子发射断层扫描技术，对53例因冠心病和左心室功能障碍而计划进行冠状动脉血运重建的患者进行心肌灌注和葡萄糖摄取评估。从手术中功能障碍区域的中心获取透壁活检标本，定量分析组织纤维化程度和心肌细胞潜在可逆性改变（肌丝丢失和糖原积累）的存在情况。用光学显微镜对这些标本进行分析。通过手术前后对比心室造影或超声心动图检查左心室功能的变化，评估收缩功能的恢复情况。
根据术后局部室壁运动变化，34例患者左心室功能被认为有所改善，而19例患者功能障碍持续存在。室壁运动改善的患者，射血分数提高了12%，收缩末期容积减少了28%。相比之下，功能障碍持续的患者，射血分数下降了6%，收缩末期容积增加了25%。在血运重建前，具有可逆性功能障碍的心肌比具有持续性功能障碍的心肌表现出更高的绝对心肌血流量、更高的心肌葡萄糖摄取、更少的组织纤维化以及更多改变的心肌细胞。在局部血流量与纤维化覆盖的活检标本面积之间，以及葡萄糖摄取与改变的心肌细胞密度之间，发现了显著相关性。
在左心室缺血性功能障碍患者中，手术血运重建后局部和整体左心室功能的恢复与术前较高的血流量和葡萄糖摄取、较少的组织纤维化以及功能障碍区域较多的存活心肌细胞有关。因此，本研究证实了术前无创代谢成像在识别残余存活心肌和预测血运重建后功能结局方面的价值。
