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

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 analyzed, calculating the AHI. A control group without aortic pathology was stratified for the same risk index, 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 Center for multidisciplinary risk assessment.