Exploring the role of ascending aortic length to prevent type A acute aortic dissection

Stanford type A acute aortic dissection (AAD) often occurs before the given threshold for prophylactic surgery. This study investigates the role of the ascending aortic length (AAL) integrated to aortic height index (AHI) as an additional factor in the risk stratification of AAD. Thereby, the relationship between AAL and the aortic diameter, as well as the patient's height, will be evaluated.

Patients undergoing surgery for AAD at our Institution between January 2013 and February 2024 were prospectively collected and retrospectively analysed. The size of the aortic organ was retrospectively measured using computed tomography to define the maximum diameter and the length of the ascending segment by means of syngo.via. The AHI and AHI + length (AHIL) were calculated and compared in all patients. A control group without known aortic pathology had their ascending aorta studied using magnetic resonance imaging, including those with a moderate risk of dissection (AHI >= 2.9 cm/m).

During the study period, 119 patients were included. The mean aortic diameter at the time of diagnosis was 5.07 ± 0.6 cm, the mean AAL was 11.94 ± 2.23 cm. In the AHI probability density function, the peak for dissection was 2.94 ± 0.36 cm/m, while for AHIL was 9.8 ± 1.15 cm/m. The difference between the AHI and the AHIL in the risk categorization was highly significant (p < 0.0001). In 12 high-risk patients with aortic enlargement, from a cohort of 6,990 individuals with non-aortic MRI indications, the inclusion of AAL to AHI also changed the categorization risk (p < 0.002).

The addition of ascending aortic length to the aortic height index provides a potentially useful exploratory morphologic index available to the cardiologic community, helping to discriminate individuals within the moderate risk for acute aortic events. Patients with an AHIL exceeding 9.7 cm/m should be referred to an Aortic Center for a proper multidisciplinary risk evaluation.