Abstract: Background　Acute aortic dissection （AAD） is a rare but fatal aortic disease if left untreated.Patients with continuous severe chest and back pain，high risk factors and obvious physical findings are hardly misdiagnosed or have a missed diagnosis，but those with atypical symptoms are difficult to be diagnosed timely.Therefore，it is urgent to formulate diagnostic framework for atypical AAD.Objective　To summarize a rapid emergency diagnostic and therapeutic procedure for atypical AAD，and to analyze the improvement in waiting time for a confirmed diagnosis and retention time in emergency department.Methods　We collected the clinical data of 91 AAD patients who had been diagnosed and misdiagnosed by Department of Emergency，Maanshan People's Hospital from January 2012 to December 2018，and divided them into typical AAD group（n=51） and atypical AAD group（n=40）according to clinical manifestations and final diagnostic results，then further divided atypical AAD patients into control subgroup （n=24，admitted from January 2012 to December 2015），and observation subgroup （n=16，admitted from January 2016 to December 2018） according to the admission time.We used two diagnostic procedures although efforts have been made to explore and improve the procedure since the first atypical patient had been found in our hospital in 2012.Before 2016，due to insufficient understanding of AAD，we diagnosed suspected AAD patients without performing examinations such as routine blood test，measurement of serum C-reactive protein，electrolytes，and amylase，ECG，liver and kidney functions，urine amylase，PT，APTT，TT and FIB，myocardial enzyme and CTnI，and D-Dimer，as well as CT scan when necessary.Since 2016，we used a different diagnostic procedure revised based on gradually improved understanding of atypical AAD gained by years of summary and learning of aortic disease-related knowledge and literature review，and the suspected AAD patients are diagnosed based on data including the aforementioned examinations，for those highly suspected，if the aforementioned examinations are not sufficient to make a confirmed diagnosis，aortic angiography was performed additionally.We compared the demographic data，missed diagnosis，misdiagnosis，time of confirmed diagnosis，retention time in emergency department，and outcome across the typical patients，control and observation atypical patients.Results　Sex ratio （χ2=0.024，P=0.989） and mean age （F=2.594，P=0.080） showed no significant differences across typical AAD group，control and observation atypical AAD subgroups.One observation atypical patient and 1 control atypical patient as well as 5 typical patients were misdiagnosed.The mean time for making a diagnosis for those with correct diagnosis in typical AAD group，control atypical AAD subgroup and observation atypical AAD subgroup was （27.6±16.8） min，（38.8±21.6） min，and （19.1±7.4） min，respectively，showing a significant difference（F=6.180，P=0.003）.The mean retention time in emergency department for typical AAD group，control and observation atypical AAD subgroups was 0，3.4（8.9） hours，and 1.5（1.0） hours，respectively.The control atypical AAD subgroup had a longer mean retention time in emergency department than observation atypical AAD subgroup （Z=-3.875，P<0.001）.77 patients were transferred to higher level hospitals，the other 12 patients were treated in our hospital，11 of whom received pharmacological treatment，and the other 1 received stent implantation.Two typical AAD patients died within 1 hour after diagnosis.Conclusion　To improve the diagnostic accuracy of atypical AAD to save time for further treatment，measurement of D-Dimer and CT scan or together with CTA when necessary should be performed for suspected atypical AAD patients during the initial examination as far as possible.In addition，learning of clinical symptoms and imaging features of atypical AAD should be strengthened in front-line clinicians and emergency diagnostic and therapeutic procedure for atypical AAD should be standardized.

Key words: Aortic diseases；Acute disease；Emergency treatment；Emergency department, hospital；Risk assessment；Delay time；Definite diagnostic time

摘要： 背景　急性主动脉夹层（AAD）临床上少见，如未及时发现将出现致命危险。以胸背部剧烈疼痛伴高危病史及体征的典型AAD不易被误诊和漏诊，而以不典型临床表现的AAD患者，极易被临床误诊或漏诊，因此，对不典型AAD的诊断研究日益凸显其重要性。目的 总结急诊快速诊断不典型AAD的诊治流程，并观察该流程对患者确诊时间及急诊科滞留时间的改善情况。方法　收集2012年1月—2018年12月由马鞍山市人民医院急诊科确诊和误诊的符合纳入标准的91例典型和不典型AAD患者的临床资料。依据临床表现和最终诊断结果将患者分为典型AAD组51例和不典型AAD组40例；再根据入院时间不同将不典型AAD组分为对照亚组（2012年1月—2015年12月入院）24例和观察亚组（2016年1月—2018年12月入院）16例。急诊诊断流程：自2012年发现并确诊第1例不典型AAD患者后不断探索和改进该类患者的急诊诊断流程。2016年前，由于对不典型AAD尚处于认识不充分阶段，并没有对疑似不典型AAD患者同时进行常规检查（血常规、C反应蛋白、心电图、肝肾功能、血电解质、血尿淀粉酶、凝血四项、心肌酶和肌钙蛋白I）和D-二聚体及必要时的CT检查，经过多年总结与深入学习主动脉疾病相关知识，并结合相关文献，逐渐加深对不典型AAD的认识，形成修改后的急诊流程，即上述检查同时进行，并对高度疑似患者、经CT平扫不能确诊的不典型AAD患者及时给予主动脉CT血管造影（CTA）检查。记录患者的一般资料、漏诊情况、误诊情况、确诊时间、急诊科滞留时间、转归情况，并进行比较。结果　典型AAD组、对照亚组、观察亚组患者性别（χ2=0.024，P=0.989）、年龄（F=2.594，P=0.080）比较，差异无统计学意义。急诊科诊断时，对照亚组和观察亚组各误诊1例患者，典型AAD组误诊5例。典型AAD组于急诊诊断正确的46例患者，其确诊时间为（27.6±16.8）min；对照亚组于急诊诊断正确的23例患者的确诊时间为（38.8±21.6）min；观察亚组于急诊诊断正确的15例患者的确诊时间为（19.1±7.4）min。三组于急诊诊断正确的患者的确诊时间比较，差异有统计学意义（F=6.180，P=0.003）。典型AAD组患者不存在急诊科滞留时间；对照亚组患者急诊科滞留时间为3.4（8.9）h，长于观察亚组的1.5（1.0）h（Z=-3.875，P<0.001）。91例AAD患者中，77例转至上级医院，11例在本院予药物治疗，1例在本院给予支架植入治疗，2例典型AAD患者死亡（均在确诊后的1 h内死亡）。结论　对有不典型症状的疑似不典型AAD患者，应尽可能在患者首次检查时考虑同时给予D-二聚体和CT及必要的CTA检查；加强一线临床医生对不典型AAD各种临床症状和影像学征象的学习，规范科室对不典型AAD的诊断流程，从而提高该类患者的诊断正确率，为其进一步救治赢得时间。

关键词: 主动脉疾病, 急性病, 急诊处理, 急诊室, 医院, 危险性评估, 滞留时间, 确诊时间