Challenges of applying circulating biomarkers for abdominal aortic aneurysm progression

As a prevalent potentially life-threatening condition, abdominal aortic aneurysm (AAA) presents increasing risk of rupture as its diameter grows. However, rapid progression and rupture may occasionally occur in smaller AAAs. Earlier surgery for patients with high risk of disease progression may improve the outcome. Therefore, more precise indicators for invasive treatment in addition to diameter and abdominal symptoms are demanded. This systematic review aimed to identify potential circulating biomarkers that may predict growth rate of AAA. Cochrane and PubMed library were searched (until August 2020) for researches which reported circulating biomarkers associated with AAA expansion, and 25 papers were included. Twenty-eight identified biomarkers were further classified into five categories (inflammation and oxidative stress, matrix degradation, hematology and lipid metabolism, thrombosis and fibrinolysis, and others), and discussed further with their correlation and regression analysis results. Larger prospective trials are required to establish and evaluate prognostic models with highest values with these markers.