Optimal Reclassification of Aortic Aneurysms: Cross-Sectional CT vs 2D Transthoracic Echocardiography

Ascending aortopathy (AA) is largely asymptomatic but carries risk for death, dissection, or rupture. Typical guidelines approach of recommending surgery based on aortic diameters is limited, as most dissections occur at AA diameters <5 cm.

The authors compared transthoracic echocardiography (TTE) and gated contrast-enhanced (CE)-computed tomographic angiography (CTA) for AA assessment and evaluated the prognostic utility of indexed parameters (aortic diameter height index [AHI] and cross-sectional area to height ratio [CSAH]).

In 7,459 patients with AA (≥4 cm) undergoing both TTE and CTA, the authors assessed the concordance of aortic measurements and the prognostic value of absolute and indexed metrics for adverse outcomes (mortality, dissection, or rupture).

Compared with CE-CTA, TTE underestimated aortic size (particularly for aneurysms ≥5 cm) in 58% of aortic roots and 37% of mid-ascending aortas. At 3.6 ± 3.6 years, there were 865 (11.6%) composite events (708 [9.5%] deaths, 173 aortic dissections [2.3%], and 12 ruptures [0.2%]). Addition of individual AA cutoffs provided incremental prognostic value for the composite endpoint (all P < 0.001) as follows: 1) aortic diameter ≥5 cm (HR: 2.42; 95% CI: 1.77-2.99); 2) AHI >3.20 cm/m (HR: 3.24; 95% CI: 2.22-4.17); and 3) CSAH ≥10 cm²/m (HR: 2.09; 95% CI: 1.55-2.39). In 5,213 unoperated patients, 63% and 86% events occurred at diameters <5 cm and AHI ≤3.21 cm/m, respectively, whereas CSAH ≥10 cm²/m was associated with 53% events.

Indexed parameters, particularly CSAH, improve risk stratification beyond absolute diameters and highlight size-based differences in AA. CE-CTA-derived indices provide an individualized precision imaging-based approach to surgical decision-making.