Site-Specific Analysis of Thoracic Aortic Aneurysm and Cardiovascular Mortality: Insights From the National Echo Database Australia.

BACKGROUND

Aortic diameter remains the most utilised criterion for considering surgical correction of thoracic aortic aneurysm (TAA). In uncomplicated cases, guidelines do not differentiate between the sizes of aneurysms at the root and the ascending aorta (AscAo). To improve practice, greater understanding of site-specific TAA is needed. A nationwide echocardiographic data set linked to mortality outcomes was examined to determine how TAA affects cardiovascular disease (CVD) mortality.

METHODS

The National Echo Database Australia (NEDA) was examined for aortic dimensions at the sinuses of Valsalva, sinotubular junction, and AscAo. Patients were stratified according to absolute aortic diameters and grouped as normal (<4 cm) or mildly (≥4 to <4.5 cm), moderately (≥4.5 to <5 cm), or severely (≥5 cm) dilated at the prescribed thoracic aortic sites. Mortality data were linked from the National Death Index.

RESULTS

A total of 477,501 echocardiograms from 175,158 patients with 2,897,357 patient-years of follow-up were included. Severe TAA at any site increased the likelihood of 10-year CVD mortality compared with normal aortic diameters (31% vs 14%, P < .0001), with incremental increase in the probability of CVD death when moving from the proximal to the distal AscAo; CVD mortality at the sinuses of Valsalva was 30% (hazard ratio [HR], 1.79; 95% CI, 1.2-2.67; P = .004), at the sinotubular junction was 41% (HR, 1.91; 95% CI, 1.11-3.29; P = .002), and at the AscAo was 45% (HR, 3.96; 95% CI, 2.06-7.64; P < .001).

CONCLUSIONS

Severe TAA increases the probability of cardiovascular mortality. Given the low event rate of aortic death (0.2%) this is not explained solely by increased dissection risk. Interestingly, there is a doubling of CVD mortality likelihood when moving from the proximal to the distal AscAo. These results suggest that patients with severe ascending aortic dilatation may be at higher CVD risk compared with those with aortic root aneurysms, identifying new considerations for risk stratification and surgical management.