Background: Prospective data on the clinical course of the ascending thoracic aorta are lacking.

Objectives: To estimate growth rates of the ascending aorta and to evaluate occurrences of adverse aortic events (AAE), i.e., thoracic aortic ruptures, type A aortic dissections, and thoracic aortic-related deaths.

Methods: In this prospective cohort study from the population-based, multicenter, randomized Danish Cardiovascular Screening trials (DANCAVAS I+II), participants underwent cardiovascular risk assessments including electrocardiogram-gated non-contrast computed tomography (CT) scans. The clinical database was supplemented with outcome data from Danish healthcare registries. Exclusion criteria were connective tissue disorders, bicuspid aortic valves, and survivors of prior AAE. To estimate growth rates, participants with consecutive CT scans were followed from inclusion to last scan. To evaluate AAE, the entire cohort was followed from inclusion to AAE, elective ascending aortic surgery, death, and December 31st, 2021.

Results: In 2,026 individuals (77.3% men, mean age 69.2+/-3.1 years, median follow-up 4.5 years (IQR: 3.4-4.7)), 4,897 CT scans were obtained encompassing 1,374 individuals with baseline ascending aortas <40.0 mm (68.3% men), 388 between 40.0-44.9 mm (94.5% men), 188 between 45.0-49.9 mm (98.4% men), and 76 men >=50 mm. The mean ascending aortic growth rates in men and women were 0.07+/-0.5 mm/year and 0.13+/-0.3 mm/year (P=0.012), respectively. Growth rates did not increase with larger diameters, and no differences were observed between small (<39.9 mm, 0.11+/-0.5 mm/year) and large (>=50 mm, 0.07+/-0.6 mm/year)(P=0.60) aortas. In men with dilated aortas between 45.0-49.9 mm, 3.2% progressed to >=50.0 mm over 4.6 years (IQR: 4.0-5.6). Amongst all 14,962 non-syndromic participants (95.0% men, mean age 67.7+/-3.7 years, median follow-up 5.0 (IQR: 4.1-5.8) years), 23 (0.2%) encountered AAE (31/100,000 person-years), while 26 (0.2%) underwent elective ascending aortic surgery. In size-groups <40.0, 40.0-44.9, 45.0-49.9, and >=50.0 mm, proportions of AAE were 10/11,382 (0.1%), 5/2,997 (0.2%), 7/493 (1.4%), and <3/90, respectively.

Conclusions: In men aged 60-74 years, growth of the ascending aorta was slow, questioning the currently recommended (bi)annual surveillance scan intervals. Additionally, 95% of AAE cases presented diameters <50.0 mm upon event, highlighting the need for individualized risk stratifications in addition to diameter. Larger prospective studies in aneurysmal women are warranted.

Editors
Editor-in-Chief
Harlan M. Krumholz, MD, SM, FACC 

CME Editor
Ragavendra R. Baliga, MD

Author
Stanislav Henkin, MD

Important Dates
Date of Release: February 24, 2025
Term of Approval/Date of CME/MOC Expiration: February 23, 2026