Height Index and Diameter as Predictors of Outcomes in Males With Abdominal Aortic Aneurysms

Introduction

Abdominal aortic aneurysms (AAAs) affect over 1 million adults in the United States, with current guidelines recommending elective repair for males at diameters greater than 5.5 cm. While aneurysm diameter (AD) remains the primary predictor of rupture in men, indexed measurements such as the aortic size index (ASI) and aortic height index (AHI) may improve risk stratification. This study aims to evaluate the association between AD, ASI, and AHI with aortic-related complications in male patients following elective AAA repair.

Methods

We conducted a single-center retrospective cohort study between 2014 and 2024 in male patients who underwent open or endovascular (endovascular aneurysm repair or fenestrated-endovascular aneurysm repair) AAA repair. Ruptured and saccular aneurysms were excluded. The primary outcome was 30-d and mid-term follow-up aortic-related complications and reintervention. Bivariate analysis was performed between the outcomes and stratified ASI (>2, >2.5, >3, and >3.5), AHI (>2.5, >3, >3.5, and >4), and AD in cm (>5, >5.5, >6, and >6.5 cm). Cox regression analysis was performed between each index as a continuous variable and each outcome. Area under the receiver operating characteristic curve analysis was conducted, and cumulative proportions were calculated.

Results

Two hundred male patients were included with a mean age of 74.3 ± 8.5 y. Bivariate analysis demonstrated no significant association between ASI, AHI, or AD categories and 30-d aortic-related complications. During follow-up (mean: 2.6 ± 2.8 y), larger AD at the time of repair was significantly associated with an increased rate of aortic-related complications (AD > 5.5 cm: P = 0.01; >6 cm: P = 0.02; >6.5 cm: P = 0.02) and reinterventions at mid-term (AD > 5.5 cm: P = 0.02; >6 cm: P = 0.02; >6.5 cm: P = 0.01). In Cox regression analysis, AD (hazard ratio [HR]: 2.13, 95% confidence interval [CI]: 1.41-3.2) and AHI (HR: 3.26, 95% CI: 1.47-7.22) were independently associated with mid-term aortic-related complications. Similarly, AD (HR: 1.72, 95% CI: 1.20-2.47) and AHI (HR: 2.21 95% CI: 1.13-4.32) were independently related to reinterventions at mid-term. Cumulative proportions for 30-d complications were 66.7%, 38.5% for mid-term complications, and 39.1% for reinterventions at a 5.5 cm AD, which was equivalent to ASI of 3.2 cm/m² and AHI of 2.9 cm/m for 30-d complications and ASI of 2.35 cm/m² and AHI of 2.9 cm/m for both mid-term complications and reinterventions.

Conclusions

Larger AD at the time of repair was associated with increased rates of mid-term aortic-related complications and reinterventions for diameters exceeding 5.5 cm. Cox regression analysis identified AD and AHI as independent predictors of mid-term complications and reinterventions. Indexed metrics for risk stratification promote personalized management approaches for AAA repair.