Abstract 4147295: Outcomes after Acute Thoracic Aortic Dissection in Children and Young Adults ≤30 years of age

Background: Thoracic aortic dissection (TAD) is rare in patients under 30 years of age, and is associated with high morbidity and mortality. There is limited published data on factors impacting survival and long-term outcomes after TAD in younger patients. Objective: Genetic and clinical findings associated with TAD in patients aged 30 and younger were analyzed to identify predictors of long-term post-dissection outcomes. Methods: This retrospective cohort study included patients from the Collaborative for Longitudinal Aortic Research in the Young and the Montalcino Aortic Consortium. Any patient with a type A or type B TAD that occurred at the age of 30 or younger was included. Results: A total of 62 patients were included (53% male). Median age at first TAD was 23.9 years (IQR 18.0-27.0) with range of 3.0 to 30.8 years; 40 (65%) were type A and 22 (35%) were type B dissections. All patients carried a genetic diagnosis, as this is required for both registries, with the highest proportion carrying TGFBR2 or ACTA2 pathogenic variants (PVs, Figure 1A). Median post-TAD follow-up was 7.8 years (IQR 2.1-11.9). Overall survival was 85% [76-95%], 83% [74-93%], and 75% [64-88%] at 1, 5, and 10 years, respectively. Freedom from death or additional aortic event was 79% [69-90%], 72% [61-86%], and 55% [42-72%] at 1, 5, and 10 years and was lower for individuals with TGFβ pathway ( SMAD3 , TGFB2 , TGFBR1 , TGFBR2 ) PVs compared to PVs in smooth muscle ( ACTA2 , MYLK , PRKG1 ) or extracellular matrix genes ( COL3A1 , FBN1 ) (p=0.12) (Figure 1B). In univariable Cox regression analysis, only aortic rupture at the time of initial TAD (HR 3.0 [1.2-7.6], p=0.018) and type A dissection (HR 3.9 [1.1-13.2], p=0.029) were significant predictors of death or additional aortic event (Table 1). Conclusion: TAD in young patients causes significant morbidity and mortality. Long-term outcomes may vary by dissection type, presence of aortic rupture, and mutated gene.