Ascending aortic aneurysm and dissection risk: focus on aortic height index

Abstract

Objectives: Acute aortic dissection (AAD) commonly occurs with a dilation of the ascending aorta at diameters under the threshold of surgical indication. Aortic diameter/height index (AHI) has been proposed for risk stratification and more accurate prophylactic surgery.

Methods: From January 2001 to November 2023, all patients operated on for AAD at our Institute were prospectively collected and retrospectively analysed, calculating the AHI. A Control Group without aortic pathology was stratified for the same risk index, and a modelling risk analysis for aortic dissection was also performed.

Results: A group of 210 patients was operated during the study period, of whom 168 (80%) had a prevalent post-junctional aortic dilation with a mean aortic diameter at the time of diagnosis of 5.1 ± 0.7 cm. In 53/210 (25%), the aortic diameter was > 5.5 cm. According to AHI, 19/210 patients (9%) were low-risk, 142/210 (67.6%) moderate, 45/210 (21.3%) high and 4/210 (2%) severe risk. In the AHI probability density function, the peak for dissection was 2.93 cm/m for males and 3.05 for females. Control were 6343 patients (3.2% at moderate risk) with AHI of 2.01 cm/m. After simulating the dissecting process, 215 (3.3%) had AHI ≥ 2.9 cm/m.

Conclusions: The measurement of the aortic diameter to height index in patients with acute aortic dissection revealed a significant prevalence of individuals presenting a moderate risk for acute aortic events. Regardless of absolute aortic diameter values, patients with AHI exceeding 2.9 cm/m should be referred to an aortic centre for multidisciplinary risk assessment.

Keywords: acute aortic dissection risk; aortic diameter/height index; ascending aorta aneurysm; prevention.