Abstract: Background  About 1/3 of patients with ST-segment elevation myocardial infarction（STEMI） have delayed visits.The benefits of late myocardial salvage therapy are affected by the severity of coronary microvascular occlusion（MVO）．Objective  To investigate the clinical outcomes，and related factors of MVO in coronary microvascular obstruction in patients with delayed admission after acute myocardial infarction.Methods  From 2014 to 2017，78 STEMI patients with delayed admission（time between symptom onset and hospital arrival is greater than 12 hours） who received emergency percutaneous coronary intervention（PCI） in EICU and CICU，Hainan General Hospital were enrolled.According to the results of coronary angiography，MVO is determined when the thrombolysis in myocardial infarction（TIMI） perfusion grade is less than 2 or the final TIMI grade is 3 and the myocardial blush grade（MBG） is less than 2.Clinical results and echocardiographic follow-up were performed to assess the occurrence of major adverse cardiovascular events（MACE） and left ventricular remodeling.Results  The incidence of MVO in the participants was 50.0%（39/78）．Multivariate Logistic regression analysis showed that older age and having left anterior descending branch as the culprit vessel were risk factors for MVO，and pre-infarction angina pectoris was protective factor for MVO（P<0.05）．The incidence of MACE and left ventricular remodeling in patients with MVO were higher than those of patients without（P<0.05）．Cox proportional hazards regression model showed that MVO and LAD were the predictors of MACE（P<0.05）．Conclusion  STEMI patients with delayed admission are relatively susceptible to MVO and related adverse outcome events.Older age and having LAD as the culprit vessel are associated with increased risks while pre-infarction angina pectoris is associated with decreased risk of MVO.Appropriate management and follow-up strategies should be implemented in this group of high-risk patients.

Key words: Myocardial infarction, Delayed treatment, Microvascular obstruction, Treatment outcome, Root cause analysis

摘要： 背景  约1/3的ST段抬高型心肌梗死（STEMI）患者出现就诊延迟，晚期心肌挽救治疗的益处受冠状动脉微血管阻塞（MVO）严重程度的影响。目的  探讨急性心肌梗死后就诊延迟患者发生MVO的影响因素及临床结局。方法  选取2014—2017年海南省人民医院急诊重症监护室和心脏重症监护室收治的就诊延迟（症状出现到就诊时间>12 h）、行急诊经皮冠状动脉介入治疗（PCI）的STEMI患者78例。根据冠状动脉造影结果，以心肌梗死溶栓试验（TIMI）血流分级≤2级或最终TIMI血流分级为3级且心肌灌注呈色等级（MBG）<2级为发生MVO。进行临床结局和超声心动图检查随访，以评估主要不良心血管事件（MACE）和左心室重构的发生情况。结果  就诊延迟患者的MVO发生率为50.0%（39/78）。多因素Logistic回归分析结果显示，年龄大、罪犯血管为左前降支（LAD）是MVO发生的危险因素，梗死前心绞痛是MVO发生的保护因素（P<0.05）。有MVO患者的MACE发生率、左心室重构比例高于无MVO患者（P<0.05）。Cox比例风险回归模型分析结果显示，MVO、罪犯血管为LAD是MACE发生的预测因子（P<0.05）。结论  STEMI后就诊延迟患者的MVO及与其有关的预后不良事件发生风险较高，年龄大、罪犯血管为LAD是其危险因素，梗死前心绞痛是其保护因素，应对存在高风险的患者实施适当的管理和后续策略。

关键词: 心肌梗死, 就诊延迟, 微血管阻塞, 治疗结果, 影响因素研究