ObjectiveTo explore the risk factors for 24-hour death in acute type A aortic dissection (ATAAD) patients with conservative treatment.MethodsFrom January 2009 to January 2018, 243 ATAAD patients who received non-surgical intervention were admitted in Beijing Anzhen Hospital, including 167 males and 76 females with an average age of 53.0±12.0 years. The risk factors for 24-hour mortality were analyzed.ResultsThe total in-hospital mortality rate was 37.9% (93/243), and 13.6% (33/243) patients died within 24 hours of onset. We found that left ventricular end diastolic diameter [LVEDD, OR=0.45, 95%CI (0.25, 0.83), P<0.01] and aortic regurgitation [OR=7.26, 95%CI (1.67, 31.53), P<0.01] were independent risk factors for 24-hour death in patients with ATAAD.ConclusionIn this study, LVEDD and aortic regurgitation are identified as independent risk factors for 24-hour mortality in ATAAD patients. Therefore, patients with aortic regurgitation and small LVEDD should be treated with sugery as soon as possible.