Myocardial fatty-acid, glucose, and total oxidative metabolism in patients with myocardial infarction and left ventricular remodeling

急性心肌梗死（MI）患者在亚急性期和/或慢性期左室壁代谢源发生改变，远端正常区左室重构，与患者预后有关。据此，我们研究了心肌梗死亚急性期心肌血流量、心肌脂肪酸代谢和心肌总氧化代谢之间的关系。此外，我们还研究了慢性期心肌梗死和左室重构患者远端正常区心肌氧化活性。1)利用正电子发射断层扫描（PET）从棕榈酸β -氧化的角度研究心肌脂肪酸代谢。用单指数方程计算了14例心肌梗死患者心肌中^<11> c -醋酸酯（醋酸酯- kmono）和^<11> c -棕榈酸酯（棕榈酸- kmono）的清除率常数，并计算了心肌初始血流的区域相对血流，评价了^<11> c -醋酸酯的分布和左心室壁运动。心肌血流良好，维持心肌脂肪酸β -氧化对心肌总氧化代谢和左室壁运动的维持具有重要意义。发现^<11> c -棕榈酸酯早期清除率是否符合单指数曲线，可能为心肌脂肪酸β -氧化的评价提供重要信息。2)对8例心肌梗死合并糖尿病（DM）患者、10例心肌梗死不伴糖尿病（DM）患者和6名健康志愿者，采用PET检测远端正常区^<11> c -乙酸酯清除率常数（Kmono）的氧化代谢。所有心肌梗死患者均有单支冠状动脉病变。心肌梗死患者可见明显的左室重构。心肌梗死患者远端正常区Kmono较正常志愿者明显降低，这是所有左室壁roi的平均值。这种远端正常区合并左室重构的心肌氧化代谢受损，说明该区域心肌不是正常而是受损，被认为是心肌梗死后左室重构患者预后不良的原因之一。DM患者与非DM Less患者远端正常区Kmono无显著差异

In patients with acute myocardial infarction (MI), alteration of metabolism sources is observed on left ventricular (LV) wall and LV remodeling is provoked in remote normal region in sub-acute and/or chronic phases, being related to the patients' prognosis. Accordingly, we investigated the relationships between myocardial blood flow, myocardial fatty-acid metabolism, and myocardial total oxidative metabolism in patients with MI in sub-acute phase. Furthermore, we also studied the myocardial oxidative activity in remote normal region in patients with MI and LV remodeling in chronic stage.1)We investigated myocardial fatty acid metabolism from the viewpoint of palmitate beta-oxidation using positron emission tomography (PET). The clearance rate constant of ^<11>C-acetate (acetate-Kmono) and that of ^<11>C-palmitate (palmitate-Kmono) from myocardium were calculated using a monoexponential equation in 14 patients with MI. Regional relative myocardial blood flow calculated from the initial … More distribution of ^<11>C-acetate and left ventricular (LV) wall motion were also evaluated. Maintained myocardial fatty acid beta-oxidation with better myocardial blood flow is substantial for preserving total myocardial oxidative metabolism and LV wall motion in patients with MI. The finding whether the early-phase clearance of ^<11>C-palmitate is fitted with a monoexponential curve may provide important information in the evaluation of myocardial fatty acid beta-oxidation.2)In 8 patients with MI with diabetes mellitus (DM), 10 with MI without DM, and 6 healthy volunteers, we studied the oxidative metabolism as the clearance rate constant (Kmono) of ^<11>C-acetate in remote normal region using PET. All patients with MI had single vessel coronary artery disease. Apparent LV remodeling was observed in patient with MI. Kmono in remote normal region in patients MI was significantly decreased compared with the Kmono in normal volunteers, which was obtained as a mean value of all ROIs on the LV wall. This impaired myocardial oxidative metabolism in remote normal region with LV remodeling indicates that the myocardium in such a region is not normal but damaged, and it is considered to be one of the reasons for poor prognosis of the patients having LV remodeling after MI. No significant difference was observed in Kmono in remote normal region between the patient with DM and those without DM Less