Among 1,022 probands with thoracic aortopathy assessed at a Canadian cardiac clinic between 2009 and 2024, only 43.5% successfully initiated family screening — yet of those relatives who were screened, 27.6% tested positive. Predictors of a positive family screen included extravascular syndromic features, closer biological relation to the proband, male sex, and older age in the family member. Crucially, imaging outperformed genetic testing eightfold in detecting affected relatives, and proband age under 60 at presentation was not predictive of yield.
Thoracic aortopathy — including conditions like bicuspid aortic valve-associated dilation and familial thoracic aortic aneurysm — carries serious risks of dissection and sudden death, yet its hereditary burden outside named syndromes like Marfan and Loeys-Dietz (just 4% of this cohort) is frequently underappreciated clinically. This real-world dataset is among the largest to quantify cascade screening yield in an unselected aortopathy population, and its practical message is striking: waiting for a genetic diagnosis before screening relatives wastes time and misses cases. The imaging-first recommendation aligns with emerging consensus but provides rare outcome data to support it. Limitations include retrospective design, single-center capture, and the inherent selection bias of clinic-referred probands. Uptake of only 43.5% suggests substantial screening gaps that warrant patient education interventions. As a preprint not yet peer-reviewed, findings require independent validation before reshaping formal guidelines — but the signal is clinically actionable and methodologically credible.
