Contrast-enhanced ultrasound microbubble uptake and abnormal plasma biomarkers are seen in patients with abdominal aortic aneurysms

Objective: Abdominal aortic aneurysm (AAA) growth is unpredictable. We hypothesize that contrast-enhanced ultrasound (CEUS) imaging and plasma inflammatory biomarkers (PIBs) may detect AAA wall inflammation. Methods: Patients with an AAA diameter ≥4 cm had CEUS and PIB testing at enrollment and every 6 months. Microbubble replenishment was analyzed via manually drawn regions of the aortic wall. Aneurysm growth, rupture, and repair were recorded. PIB testing was analyzed using biomarker panels. Independent and paired t-tests were used to detect differences in PIB levels. Logistic regression was used to study the association between PIBs, microbubble uptake, and AAA growth. Results: A total of 59 patients were enrolled (mean age, 68.8 ± 8.6 years; 13.6% female; 93.2% White). Mean AAA size on presentation was 41.6 ± 6.7 mm. Microbubble uptake was seen in 36 patients (61%). Patients with AAA had high baseline levels of Cystatin C and interferon-γ and low levels of macrophage migration inhibitory factor. Microbubble uptake was seen in 59% of patients with ≥5 mm AAA growth but was not predictive of growth on logistic regression. Conclusions: We have demonstrated that microbubble uptake with CEUS is seen in the aortic wall/intraluminal thrombus of patients with AAA. CEUS and PIBs could provide insight into aneurysm behavior in newly diagnosed AAA.