Impact of Non-Diameter Aortic Indices on Surgical Eligibility: Results from the TITAN: SvS Randomized Controlled Trial.

OBJECTIVES: Traditional criteria for intervention on an asymptomatic ascending aortic aneurysm has been a maximal aortic diameter of ⩾5.5cm. The 2022 ACC/AHA aortic guidelines adopted cross-sectional aortic area/height ratio, aortic size index (ASI) and aortic height index (AHI) as alternate parameters for surgical intervention. The objective of this study was to evaluate the impact of using these newer indices on patient eligibility for surgical intervention in a prospective, multicenter cohort with moderate sized ascending aortic aneurysms between 5.0-5.4 cm.

METHODS: Patients enrolled from 2018 to 2023 in the randomization or registry arms of the multicenter trial, TITAN: SvS, were included in the study. Clinical data was captured prospectively in an online database. Imaging data were derived from a core CT lab.

RESULTS: Among the 329 included patients, 20% were female. Mean age was 65.0 ± 11.6 years and mean maximal aortic diameter was 50.8 ±3.9 mm. In the one third of all patients (n=109) who met any one of the three criteria (i.e., ASI ⩾ 3.08 cm/m2, AHI ⩾ 3.21 cm/m or cross-sectional aortic area/height ⩾ 10 cm2/m), their mean maximal aortic diameter was 52.5 ±0.52 mm. Alternate criteria were most commonly met in females compared to males: 20% versus 2% for ASI (p<0.001), 39% versus 5% for AHI (p<0.001) and 39% versus 21% for cross-sectional aortic area/height (p=0.002), respectively.

CONCLUSIONS: One third of patients in Titan:SvS would meet criteria for surgical intervention based on novel parameters vs. the classic definition of diameter⩾5.5cm. Surgical thresholds for ASI, AHI or cross-sectional aortic area/height ratio are more likely to be met in female patients compared to male patients.