Growth Trajectories in Ascending Thoracic Aortic Dilation: Classification and Implications for the Effectiveness of Real‐World Imaging Surveillance

Background Ascending aortic dilation is monitored with serial imaging, yet event rates are low, with type A dissections often occurring at non‐surgical sizes. We aimed to characterize ascending aortic growth trajectories in a real‐world population to understand their clinical consequences and better inform surveillance strategies. Methods We conducted a retrospective, single‐center study of adults with ≥2 thoracic CTA/MRA examinations. Mid‐ascending diameters from clinical reports were used to analyze real‐world surveillance effectiveness. Growth trajectories were clustered using latent profile analysis (LPA). Early (first 3 scans; n= 1,997) and Extended (first 5 scans; n= 757) LPA models each yielded four classes: Stable, Growth, Dramatic Growth and Fluctuation (an unstable trajectory attributed to measurement noise). Results We studied 3,363 adults (median age 62 years; 68% men). Stable class was most common (74 % Early; 70 % Extended); Growth and Dramatic Growth classes comprised 23% and 2% respectively. Only 1.1% met guideline growth‐based criteria for repair, and this subgroup had smaller baseline diameters (37.0 mm vs. 40.3 mm, p=0.009). At Extended follow‐up, 80% of those initially Stable remained Stable. Reclassification into a Growth class was associated with younger age and Marfan syndrome (50.0% vs 3.0%, p=0.006). Acute type A dissection was rare (0.45%) and not clearly linked to any trajectory. Conclusions Most patients with a dilated ascending aorta show negligible growth and low complication rates during routine surveillance. Repeated imaging beyond 3 scans may amplify uncertainty without clear improvements in risk stratification, suggesting that imaging surveillance may be safely de‐escalated for stable patients.