From the Guidelines
Serial CT angiography (CTA) is recommended for monitoring ascending aortic aneurysms, with follow-up intervals depending on aneurysm size and growth rate, as outlined in the 2024 ESC guidelines 1.
Key Considerations for Serial Scanning
- The best imaging modality for surveillance of ascending aortic aneurysms depends on the aneurysm location, with CTA being a preferred option due to its superior spatial resolution and faster acquisition time compared to MRI 1.
- For aneurysms that are only moderate in size and remain relatively stable over time, CMR rather than CTA is reasonable to minimize radiation exposure, especially in younger patients requiring lifelong surveillance 1.
- The follow-up interval should be customized according to the underlying condition, with imaging required at 6–12 months after initial diagnosis, depending on aetiology and baseline diameter, and subsequently performed annually if there is no expansion or extension 1.
- If the aorta shows rapid expansion (≥3 mm per year) or approaches the surgery/endovascular repair threshold, a closer evaluation is recommended every 6 months 1.
Scan Protocol and Surgical Intervention
- The scan protocol should include non-contrast images followed by contrast-enhanced acquisition with thin-slice (1-1.5 mm) reconstructions and multiplanar reformats to accurately measure the maximum diameter perpendicular to the centerline of flow 1.
- Surgical intervention is typically considered when the ascending aorta reaches a certain threshold, with the exact size depending on individual patient factors, such as the presence of genetic aortopathies like Marfan syndrome 1.
Importance of Blood Pressure Control
- Patients should be counseled on the importance of blood pressure control (target <130/80 mmHg) using beta-blockers or angiotensin receptor blockers as first-line agents to reduce hemodynamic stress on the aortic wall during the monitoring period 1.
Growth Rates and Earlier Intervention
- Growth rates exceeding a certain threshold per year, regardless of absolute size, should prompt consideration for earlier intervention, highlighting the need for regular monitoring and timely decision-making 1.
From the Research
Serial Scanning for Ascending Aortic Aneurysm with CTA
- The optimal interval for imaging surveillance of ascending aortic aneurysms is still a topic of debate, with different studies suggesting varying intervals 2, 3, 4.
- A study published in 2021 found that the mean growth rate of non-syndromic ascending aortic aneurysms was 0.2 ± 0.4 mm/year, and suggested that triennial imaging may be sufficient for aneurysms measuring 40-49 mm in diameter 4.
- Another study published in 2023 found that adult patients with non-syndromic ascending aortic aneurysms with initial diameters < 4.5 cm had very low aortic growth rates and adverse event rates, and suggested that longer intervals between surveillance imaging (up to 3-5 years) may be permissible after initial stability is documented 3.
- The use of computed tomography angiography (CTA) is recommended for the evaluation of thoracic aortic aneurysms, as it allows for precise diameter assessment and accurate preoperative planning 5.
- Electrocardiography (ECG)-gated CTA can help avoid movement artifacts and provide a more precise definition of proximal aortic segments (aortic arch, ascending aorta) 5.
Imaging Surveillance Protocols
- The European Society for Vascular Surgery guidelines recommend elective treatment of thoracic aneurysms with a diameter > 55 mm, and suggest that endovascular repair is the treatment of choice for most patients 5.
- A study published in 2020 provided guidelines for imaging surveillance after endovascular aneurysm repair (EVAR), and suggested that lifelong surveillance is necessary to detect potential complications such as endoleak 6.
- The guidelines recommend triple-phase CT angiography (CTA) within 30 days after EVAR, and annual duplex ultrasound for patients without endoleak on initial CTA 6.