Artikel
Geometric and biomechanical progression in abdominal aortic aneurysms over time
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Veröffentlicht: | 22. Dezember 2021 |
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Gliederung
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Background: Growth of abdominal aortic aneurysms (AAAs) is often described as erratic and discontinuous. The primary aim was to study the growth patterns of AAAs with respect to semi-automatic maximum aneurysm diameter (AD) and aneurysm volume. The secondary aim was to characterize changes in the intraluminal thrombus (ILT) and biomechanical indices as AAAs grow.
Methods: This retrospective cohort study included patients who presented with an intact AAA between 2012-2013 and had undergone ≥3 computed tomography-angiograms (CTAs). CTAs were analysed with respect to semi-automatic geometry (AD, aneurysm-, lumen- and ILT-volume) and finite element analysis-derived biomechanical markers (peak wall stress; PWS, peak wall rupture index; PWRI), with the Vascops A4Clinics software.
Results: In total, 384 CTAs from 100 patients (22 women) were included. The mean follow-up was 5.2±2.5 years. Annual growth of AD was 2.6 mm/year (95%CI 2.3-2.8), volume 13.73 cm3/year (11.4-16.1) and PWS 7.3 kPa/year (5.8-8.9). For AD and volume, individual patients exhibited linear growth in 87% (Figure 1 [Abb. 1]) and 77% of cases respectively. In patients with the slowest AD-growth (<2.1mm/year), only 67% belonged to the slowest tertile for volume-growth and 52% to the lowest tertile of PWS-increase. The proportion of ILT (ILT-volume / aneurysm volume) grew significantly with time (2.6%/year, p<0.001), but when adjusting for aneurysm volume the proportion of ILT was inversely associated with increase of biomechanical stress. AD, volume and PWRI increase was significantly higher among current and previous smokers, as compared to non-smokers.
Conclusion: Contradictory to many reports, these results show that growth patterns for AD and volume can in most patients adequately be described by linear models. Volume and PWS growth were comparatively higher for many patients with slow AD growth. The proportion of ILT increased with time, but was related to lower biomechanical stress. Smoking was not only related to increased AD- and volume-growth rates, but also to a faster biomechanical progression.
Competing interests: C. Gasser is scientific advisor for Vascops.