Background: This study investigated the impact of coronary angiography on outcomes of emergency operation in acute type A aortic dissection (ATAAD) patients who were initially misdiagnosed as the acute coronary syndrome.Methods: From October 2016 to April 2019, 129 patients underwent surgery for ATAAD in our institution, including 21 patients (16.3%, CA group) who received preoperative coronary angiography without knowledge of the ATAAD, and the rest 108 did not (NCA group). Preoperative clinical characteristics, surgical mortality and postoperative complications were compared. Multivariable logistic regression was performed to confirm the independent prognostic factors for short-term and long-term outcomes.Results: Patients undergoing coronary angiography had higher prevalence of preoperative hypotension or shock (61.9% vs 35.2%, P=0.022), ischemic changes on electrocardiogram (66.7% vs 37.0%, P=0.012), platelet inhibition (ADP-induced inhibition 92.0% vs 46.0%, P=0.001), and coronary involvement (66.7% vs 30.6%, P=0.002). 30-day/in-hospital mortality was 4.8% versus 9.3% (P=0.84). CA group had more intraoperative bleeding (1900ml vs 1500ml, P=0.013) and chest-tube drainage on the first postoperative day (1040ml vs 595ml, P=0.028). However, preoperative coronary angiography was not independent risk factors for surgical mortality (OR 0.171, 95%CI 0.013-2.174, P=0.173) and overall survival (HR 0.407; 95%CI 0.080-2.057; P=0.277). Conclusion: Patients undergoing coronary angiography carried a higher risk of preoperative hemodynamic instability, myocardial ischemia, and perioperative bleeding. However, unintentional coronary angiography did not have a significant impact on short-term and long-term outcomes of emergency surgery in ATAAD.