Blood Eosinophil Count in Asthma Is Associated With Increased Abdominal Aortic Diameter and Increased Vascular Stiffness.

Background: Asthma is associated with atherosclerosis and abdominal aortic aneurysm (AAA). However, the underlying pathomechanisms remain elusive. Blood eosinophil count (BEC) is implicated in both eosinophilic asthma and arterial wall inflammation. Objective: To explore the possible association of BEC in asthma and abdominal aortic artery changes. Methods: 112 outpatients were prospectively enrolled in this exploratory study. Abdominal aortic diameter was measured using ultrasonography imaging, while vascular speckle tracking was utilized to evaluate vascular strains. Patients were stratified into two groups, with n=66 patients with a BEC of ≥300 n/µL and n=46 patients with <300 n/µL. Both groups exhibited no significant disparities in cardiovascular risk factors; however, the high BEC group was more frequently male. Results: The aortic diameter was wider in patients with a BEC ≥300 n/µL (1.46 ± 0.25 cm vs 1.67 ± 0.63 cm, p=0.018). Three patients were diagnosed with an AAA, all had a BEC ≥300 n/µL. Patients with a BEC ≥300 n/µL exhibited lower strain values, indicative of higher vascular stiffness, including radial strain (2.65 ± 1.38% vs 4.46 ± 2.59%; p<0.001). BEC exhibited a positive correlation with abdominal aortic diameter (R²=0.131, b=0.000, p<0.001), and a negative correlation with radial strain values (R²=0.131, b=-0.002, p=0.001) in sex-adjusted linear regression. Conclusion: In patients with asthma, blood eosinophil count (BEC) is correlated with a wider aortic diameter and heightened vascular stiffness in the abdominal aorta. Hence, they may be at an elevated risk of developing an AAA.