A 4-Decade Population-Based Registry of Thoracic Aortic Dissection Causing Sudden Death in the Young

Background: Thoracic aortic dissection (TAD) causing sudden cardiac death (SCD) in the young is overlooked and poorly described. Objectives: The purpose of this study was to assess: 1) the incidence of TAD-related SCD, and 2) the prevalence and features of TAD in a young cohort with SCD. Methods: The number of residents ≤40 years in the Veneto Region, Italy (1985-2024) was calculated, and the SCD registry was searched for TAD. Clinical features and multilevel aortic diameters were assessed. Aortic histopathology was performed in all and whole exome sequencing when feasible. Results: The overall rate of TAD-related SCD in this young cohort (age 1-40 years) was 0.32 per 1,000,000 (95% CI: 0.21-0.46) people. Twenty-eight out of 941 SCD (2.9%; mean age 29.1 ± 7 years; 24 males) had TAD, including 24 type A and 4 type B. 7 (29%) also had a chronic TAD. Symptoms were present in 13 (46%) subjects. Associated conditions were bicuspid aortic valve (BAV 9, 6 with early-complex pattern including aortic coarctation in 2), hypertension (5), Marfan syndrome (2), pregnancy (2), isolated aortic coarctation (2), and Turner syndrome, previous closure of ductus arteriosus, familial TAD, and drug abuse (1 each). Genetic abnormalities were found in 8/16 TAD (50%), including 1/3 screened BAV. In type A TAD, aortic diameters were<50 mm in all but 2 cases. A heterogeneous histopathological pattern was found. Conclusions: TAD-related SCD in the young is rare, and TAD is an infrequent cause of SCD, affecting mostly men. Symptoms and chronic TAD are common, and a high index of clinical suspicion is needed for timely diagnosis. BAV (primarily the complex-phenotype) and inherited disorders are the most common associated conditions, supporting the role of routine genetic screening in this population.