Abstract Body (Do not enter title and authors here): Background:
Racial disparities are known to exist in cardiovascular disease such as acute coronary syndrome and heart failure. However, data are limited in examining possible racial disparities related to aortic dissection due to the rare nature of this disease.

Hypothesis:
We hypothesize that, among patients presenting with acute type B aortic dissection, racial differences exist in disease severity at time of presentation as well as initial management, in-hospital and long-term outcomes.

Methods:
Our analysis included white (n = 2517, 80%) and black (n = 629, 20%) patients with acute Type B aortic dissection in the International Registry of Acute Aortic Dissection collected from 62 sites between 1996 and 2024. Other races were excluded given small sample size and limited follow up data.

Results:
When compared with white patients, black patients were younger (mean age 58 ± 12 years vs 65 ± 14 years, P < .0001), and more likely to have a history of hypertension (94% vs 83%, P < .0001), diabetes (19% vs 11%, P < .0001), chronic kidney disease (18% vs 9.5%, P < .0001), and cocaine use (14% vs 1.6%, P < .0001). Black patients were also more likely to present with abdominal pain (51% vs 43%, P = .003), lower extremity pain (16% vs 11%, P = .018), hypertension (72% vs 61%, P < .0001), renal malperfusion (24% vs 12%, P < .0001), abdominal vessel involvement (58% vs 47%, P < .0001) and pericardial effusion (12% vs 6%, P = .001). Black patients were more likely to undergo endovascular management (40% vs 28%, P < .0001) and less likely to be medically managed alone (49% vs 61%, P < .0001). Prior to any intervention, black patients were more likely to experience stroke (3.3% vs 1.1%, P = .001) and extension of dissection (10% vs 7.2%, P = .028). In-hospital mortality was similar (black 6.5% vs white 8.4%, P = .139). Overall survival was also similar at 4 years post-discharge (black 86% vs white 83%, P = .172). Among patients with endovascular management, black patients had better 4-year survival (93% vs 81%, P = .028).

Conclusions:
Our analysis shows differences in baseline characteristics, presentation, management, and in-hospital adverse events for black patients presenting with acute type B dissection compared to white patients; however, without any significant difference in in-hospital or 4 year mortality. Future studies may aim to evaluate modifiable risk factors and optimal treatment strategies to reduce the incidence of aortic dissection in black patients.