Time of day does not influence outcomes in acute type A aortic dissection: Results from the IRAD

Background: Type A acute aortic dissection (TAAAD) represents a surgical emergency requiring intervention regardless of time of day. Whether such a “evening effect” exists regarding outcomes for TAAAD has not been previously studied using a large registry data. Methods: Patients with TAAAD were identified from the International Registry of Acute Aortic Dissections (1996–2019). Outcomes were compared between patients undergoing operative repair during the daytime (D), defined as 8 am–5 pm, versus the evening (N), defined as 5 pm–8 am. Results: Four thousand one-hundrd and ninety-seven surgically treated patients with TAAAD were identified, with 1824 patients undergoing daytime surgery (43.5%) and 2373 patients undergoing evening surgery (56.5%). Daytime patients were more likely to have undergone prior cardiac surgery (13.2% vs. 9.5%; p <.001) and have had a prior aortic dissection (4.8% vs. 3.4%; p =.04). Evening patients were more likely to have been transferred from a referring hospital (70.8% vs. 75.0%; p =.003). Daytime patients were more likely to undergo aortic valve sparing root procedures (23.3% vs. 19.2%; p =.035); however, total arch replacement was performed with equal frequency (19.4% vs. 18.8%; p =.751). In-hospital mortality (D: 17.3% vs. N. 16.2%; p =.325) was similar between both groups. Subgroup analysis examining the effect of weekend presentation revealed no significant mortality difference. Conclusions: A majority of TAAAD patients underwent surgical repair at night. There were higher rates of postoperative tamponade in evening patients; however, mortality was similar. The expertise of cardiac-dedicated operative and critical care teams regardless of time of day as well as training paradigms may explain similar mortality outcomes in this high risk population.