3.0TMRI 联合256层CT对慢性心梗微循环及心室重塑的基础研究

Unrecognized myocardial infarcts（UMI）are quite common in patients with coronary atery disease（CAD）whose morality is significantly higher than patients with recognized myocardial infarcts. Such infarction are usually chronic myocardial infarction. Delayed-enhanced MRI is helpful to the awareness of these chronic myocardial scars.However, there are some issues to be discussed. Is there any differences in the extent of chronic myocardial infarts detected by DE-MRI and pathology? whether the bright area on DE-MRI is myocardial infarcts? Is there any false-positive or false-negative detected by DE-MRI? And why? Whether can DE-MRI distinguish the core and the gray zone of chronic myocardial infarcts? What are pathological ingredients of the gray zone which related to supraventricular tachycardia? The myocardial microcirculation and ventricular remodeling are directly related with future survial in patients with chronic myocardial infarcts. But so far most of DE-MRI studies are only concerned on the detection of myocardial infarcts. The little is known about the affect of chronic myocardial infarcts on ventricular remodeling , for example, the correlations between chronic myocardial scars and the score of wall motion, myocardial function, the risk of arrhythmia,myocardial microcirculation,as well as the BNP levels after left wentricular remodeling . According to swine model with chronic myocardial infarction, we are going to study issues mentioned above, and compared phathological findings. Through our research ,we hope to improve the understanding about chronic myocardial infarcts, and improve the early predictions for adverse cardiac events in patients with myocardia scar, especially in UMI, and guide physians to give timely and effective treatment.

未被认知的慢性心梗（UMI）患者相当普遍，死亡率明显高于被认知的冠心病患者，国外目前有研究报道延迟增强MRI（DE-MRI）有助于对此类患者的认知。但DE-MRI检测的心梗瘢痕范围与病理一致性如何？有无假阳性、假阴性存在？产生原因和机制；能否识别慢性心梗灶中与室上性心动过速有关的灰带，识别的机制和灰带组织学成分如何？在慢性心梗患者，局部心肌微循环和心室重塑直接影响患者的将来预后。但目前研究多关注DE-MRI心梗瘢痕的检测，对DE-MRI检测的心梗瘢痕与心室重塑后肌壁厚度及室壁运动、心肌功能改变的相关性；瘢痕形态、部位、大小与重塑后心律失常的风险性、BNP水平、靶血管、局部微循环的相关性等所知很少甚或不明，本项目拟通过猪慢性心梗模型的构建，联合3.0T和258层CT对上述问题进行病理对照研究，从而提高对慢性心梗患者，特别是UMI患者的认知及心脏不良事件的早期预测、促进其预后的改善。

虽然对冠心病的研究与干预在不断增加，但其发病率和死亡率始终居高不下。相对于急性心肌梗死，慢性心梗的研究相对较少，在有关MRI与慢性心梗的研究中，多关注心梗瘢痕的检测，而对检出的心梗瘢痕对心室重塑的影响知之甚少；对于慢性心梗来说，梗死后心肌微循环、心室重塑对预后有直接的关系，因此我们对此进行了研究。研究包括了以下内容：1猪心梗模型的制作及MRI与病理对照；2急慢性期猪心梗模型微循环灌注的改变；3急慢性期猪心梗模型心室重塑的改变；4 DE-MRI检测的心梗与冠脉狭窄的相关性；5 DE-MRI检测心梗瘢痕与心室重塑指标的相关性；6 心室重塑及瘢痕特征的CMR评价与心律失常的相关性。获得了以下结果和关键数据：1应用左前降支球囊栓塞法建立小型猪心肌梗死模型，无需开胸、创伤小、模型稳定性及重复性好。心梗模型MRI透壁分级与TTC染色的相关性高（kappa值＞0.81）。2心肌梗死区周围存在发生缺血损害的心肌；一周和八周心肌灌注缺损范围无明显差异，灌注减低区域有明显差异，提示心肌梗死区心肌微循环不能恢复，而心肌梗死周围区心肌微循环可以恢复。3冠脉狭窄分级与心梗节段透壁分级相关（P＜0.05），但非高度相关（rs=0.405）；在冠脉无明显狭窄的患者，亦可检测到心梗瘢痕，以心内膜下心梗多见。4 DE-MRI检测的心梗节段及其透壁程度与左室重塑高度相关（心梗积分与WT、WTR、EF值和WM的相关系数rs1 分别为-0.788、-0.756、-0.804、0.811））；5 MRI检测的指标与室性早搏的Lown的危险分级相关，心梗积分是心梗后发生VPBs的独立危险因素；与LVEF相比（-0.558），心梗面积和心梗积分与lown分级的相关性较高（0.767，0.707）。上述结果，对于临床有很好的指导意义，通过研究开展了CMR冠心病及心肌病的临床应用，诊断了我省多例疑难病例，获得了较好的社会效益。完成与项目研究密切相关的文章12篇（已发表10篇，录用待发2篇）：SCI 3篇，北大源4篇，其他科技核心5篇，培养硕士研究生6人。