Is repeat Transthoracic Echocardiogram (TTE) necessary for mild dilation of the ascending aorta measuring 3.8 cm?

From the Guidelines

Yes, you should repeat a transthoracic echocardiogram (TTE) for mild enlargement of the ascending aorta measuring 3.8 cm. For patients with mild aortic dilation, follow-up imaging is typically recommended every 1-2 years to monitor for progression, as stated in the 2024 ESC guidelines for the management of peripheral arterial and aortic diseases 1. The specific interval depends on several factors including the underlying cause of the dilation, family history, presence of genetic conditions like Marfan syndrome, and rate of previous growth if known.

Key Considerations

• The growth rate of aortic aneurysms averages about 0.1 cm per year, but this can vary significantly between individuals.
• During this monitoring period, it's essential to maintain good blood pressure control, ideally keeping systolic pressure below 130 mmHg.
• Medications such as beta-blockers (like metoprolol 25-100 mg twice daily) or angiotensin receptor blockers may be prescribed to reduce hemodynamic stress on the aortic wall, as suggested by the 2022 ACC/AHA guideline for the diagnosis and management of aortic disease 1.
• Regular monitoring is crucial because an enlarging aorta increases the risk of dissection or rupture, particularly when the diameter exceeds 5.0-5.5 cm, at which point surgical intervention is often considered.

Surveillance Recommendations

• According to the 2024 ESC guidelines, TTE is recommended at diagnosis to assess aortic valve anatomy and function, aortic root, and ascending aorta diameters 1.
• Additionally, a global aortic evaluation using all echocardiographic views is recommended.
• CMR or CCT is recommended for surveillance of patients with aneurysm at the distal ascending aorta, aortic arch, DTA, or TAAA.
• Follow-up imaging with TTE, CCT, or CMR (based on aneurysm location) should be considered annually if there is no expansion/extension or customized according to baseline aortic diameter and the underlying condition.

Important Notes

• The 2024 ESC guidelines propose a follow-up algorithm for patients with TAA, which recommends imaging at 6–12 months after initial diagnosis, depending on aetiology and baseline diameter 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.

From the Research

Repeat Transthoracic Echocardiogram (TTE) Necessity

• The necessity of a repeat TTE for a mild dilation of the ascending aorta measuring 3.8 cm can be evaluated based on various studies.
• A study published in the Journal of cardiac surgery 2 found that progression of proximal aorta leading to adverse aortic events after isolated aortic valve replacement in tricuspid aortic valve patients is infrequent, suggesting that AVR alone is acceptable and reasonable in patients with mild to moderate proximal aortic dilatation if connective tissue disorders are not present.
• Another study published in The Journal of thoracic and cardiovascular surgery 3 recommended concomitant replacement of the ascending aorta if the diameter is 4.5 cm or greater in patients undergoing operations for bicuspid aortic valve disease.

Indications for Surgical Intervention

• A study published in Nature clinical practice. Cardiovascular medicine 4 indicated that intervention is indicated with an aortic diameter of 5.5 cm, and many would intervene even earlier (at 5.0 cm) for patients at low surgical risk, or for those with known connective tissue disorders.
• A study published in The Annals of thoracic surgery 5 suggested that operation is necessary in patients with a well-functioning bicuspid aortic valve and an ascending aorta diameter greater than 5 cm, and deferring operation in patients under surveillance in the absence of significant enlargement (>0.5 cm/year).

Surveillance and Monitoring

• The study published in The Annals of thoracic surgery 5 also found that a consistent approach to patients with a well-functioning bicuspid aortic valve and ascending aorta dilatation, recommending operation to those with an AA diameter greater than 5 cm and deferring operation in patients under surveillance in the absence of significant enlargement (>0.5 cm/year), resulted in overall survival equivalent to a normal age-matched and sex-matched population.
• The average growth rate of the ascending aorta in patients with 2 scans or greater was 0.77 mm/year, with no significant impact of hypertension, sex, smoking, or age 5.

Aortic Dilation Prevalence and Association with Cardiac Organ Damage

• A study published in the Journal of hypertension 6 found that the prevalence of ascending aorta dilatation in hypertensive patients reaches 13%, and hypertensive individuals with enlarged ascending aorta showed significantly increased left ventricular mass, a well-known sign of hypertension-related cardiac damage.