The 2010 American Society for Thoracic Surgery guidelines suggest prophylactic surgery for thoracic aortic aneurysms upon confirmation of rapid growth. However, the aortic experience at Yale New Haven highlights that many cases labeled as rapid growth stem from measurement inaccuracies, thus questioning the legitimacy of this criterion for surgical intervention.

For this purpose, they analyzed a cohort of 2.781 patients with thoracic aortic disease over a 30-year span. They selected 811 patients who had at least two spaced aortic imaging studies over a minimum of two years. Rapid growth was defined as an aortic enlargement exceeding 3 mm per year. Thus, 42 cases of potential surgical indication for rapid growth in ascending aortic aneurysms and 27 in descending aortic aneurysms were identified. All clinical, surgical, and imaging data were re-evaluated by a panel of experts to confirm their accuracy.

Among the 42 patients with ascending aortic aneurysm growth, 12 were confirmed, 11 were rejected (19 imaging tests were inaccessible). Out of the 27 patients with descending aortic growth, 6 were confirmed, and 4 were rejected (with 17 imaging tests inaccessible). Based on available data and adjusting for the unavailable studies, three likelihoods for rapid growth rates were calculated: low probability, considering only the confirmed cases; high probability, considering the confirmed cases and assuming unanalyzed studies as positive; and medium probability, taking into account the confirmed cases and prorating the rates of positive findings in the unanalyzed imaging studies. This resulted in 2.7%, 4.7%, and 6.9% rates for ascending aortic rapid growth and 1.6%, 4.3%, and 7.3% for descending aortic rapid growth, respectively. The medium rate was deemed most reflective of real-life scenarios. Among the confirmed rapid growth cases, 4 patients were deemed inoperable, of which 3 succumbed to their aortopathy. Of the remaining 23 who underwent surgery, only one patient died.

The authors conclude that while rapid aortic growth does occur, it is exceedingly rare for both ascending and descending aortas. Up to half of the cases might have been due to measurement errors, suggesting such surgeries might not have been necessary. They urge a reevaluation of patients presenting with rapid growth of thoracic aortic aneurysms and insist on reassessing radiological measurements to rule out potential measurement errors.

COMMENTARY:

The 2010 American Society for Thoracic Surgery guidelines recommend prophylactic surgery when the growth rate exceeds 5 mm per year for aortas under 55 mm. Indeed, applying a 5 mm growth threshold only yielded one case of rapid ascending aortic growth and two descending cases that met the 2010 guideline criteria within the study cohort. Variations between 3–5 mm could be due to intra- and interobserver variability, thus negating the rationale for an aggressive 3 mm/year criterion. There are five reasons for such variability: comparing non-matching segments, oblique measurements, systolic-diastolic variations of the aorta, measurements taken with versus without contrast, and measurements performed with different imaging systems, even when the same imaging technique is used, and lastly, measurements that include the arterial wall versus those that do not. Fortunately, the use of digital imaging, vascular lumen-centered techniques, and cardiac synchronization through electrocardiography during imaging can significantly reduce the variability previously mentioned. Therefore, the central message of today’s article is the rarity of rapid aortic growth, and should we encounter a similar case in our practice, the first step should be to verify that growth to rule out a measurement error.

As for the limitations of this study, its single-center and retrospective nature encompasses 30 years. Despite a large patient database, only a third were eligible for the study. The restrictive criterion of selecting patients with at least two imaging tests spaced at least two years apart led to a significant loss of potential candidates. This criterion is purely artificial and arbitrary, since consulting for dimensional changes in the aorta from one year to the next is common. Additionally, over half of the selected cases could not verify the images because they were conducted in the pre-digital era. Finally, only genomic sequencing was performed on patients from the last decade, so we do not have data to assert that malignant degeneration of some aneurysms may have a solid genetic basis.

In conclusion, today’s study shows that up to 5% of thoracic aortic aneurysms may exhibit rapid growth. Whenever we face this entity, we must ensure that measurements are accurate, because in up to half of the cases, we will be pleasantly surprised.

REFERENCE:

Sonsino A, Ellauzi H, Ziganshin BA, Zafar MA, Elefteriades JA. Rapid growth of thoracic aortic aneurysm: Reality or myth? J Thorac Cardiovasc Surg. 2024 Apr;167(4):1206-1213. doi: 10.1016/j.jtcvs.2022.06.021.