Anticoagulants and reduced thrombus load in abdominal aortic aneurysms assessed with three-dimensional contrast-enhanced ultrasound examination

Thrombosis in the pathogenesis of abdominal aortic aneurysm

Background

Abdominal aortic aneurysms (AAAs) are a relatively common vascular pathology of the elderly with high morbidity potential. Irreversible degeneration of the aortic wall leads to lethal rupture if left untreated. Nearly all AAAs contain intraluminal thrombus (ILT) to a varying degree, yet the mechanisms explaining how thrombosis is disturbed in AAA are relatively unknown. This review examined the thrombotic complications associated with AAA, the impact of thrombosis on AAA surgical outcomes and AAA pathogenesis, and the use of antithrombotic therapy in the management of this disease.

Methods

A literature search of the PubMed database was conducted using relevant keywords related to thrombosis and AAAs.

Results

Thrombotic complications are relatively infrequent in AAA yet carry significant morbidity risks. The ILT can impact endovascular aneurysm repair by limiting anatomic suitability and influence the risk of endoleaks. Many of the pathologic mechanisms involved in AAA development, including hemodynamics, inflammation, oxidative stress, and aortic wall remodeling, contain pathways that interact with thrombosis. Conversely, the ILT can also be a source of biochemical stress and exacerbate these aneurysmal processes. In animal AAA models, antithrombotic therapies have shown favorable results in preventing and stabilizing AAA. Antiplatelet agents may be beneficial for reducing risks of major adverse cardiovascular events in AAA patients; however, neither antiplatelet nor anticoagulation is currently used solely for the management of AAA.

Conclusions

Thrombosis and ILT may have detrimental effects on AAA growth, rupture risk, and patient outcomes, yet there is limited understanding of the pathologic thrombotic mechanisms in aneurysmal disease at the molecular level. Preventing ILT using platelet and coagulation inhibitors may be a reasonable theoretical target for aneurysm progression and stability; however, the practical benefits of current antithrombotic therapies in AAA are unclear. Further research is needed to demonstrate the extent to which thrombosis impacts AAA pathogenesis and to develop novel pharmacologic strategies for the medical management of this disease.

The mechanism and therapy of aortic aneurysms

Aortic aneurysm is a chronic aortic disease affected by many factors. Although it is generally asymptomatic, it poses a significant threat to human life due to a high risk of rupture. Because of its strong concealment, it is difficult to diagnose the disease in the early stage. At present, there are no effective drugs for the treatment of aneurysms. Surgical intervention and endovascular treatment are the only therapies. Although current studies have discovered that inflammatory responses as well as the production and activation of various proteases promote aortic aneurysm, the specific mechanisms remain unclear. Researchers are further exploring the pathogenesis of aneurysms to find new targets for diagnosis and treatment. To better understand aortic aneurysm, this review elaborates on the discovery history of aortic aneurysm, main classification and clinical manifestations, related molecular mechanisms, clinical cohort studies and animal models, with the ultimate goal of providing insights into the treatment of this devastating disease. The underlying problem with aneurysm disease is weakening of the aortic wall, leading to progressive dilation. If not treated in time, the aortic aneurysm eventually ruptures. An aortic aneurysm is a local enlargement of an artery caused by a weakening of the aortic wall. The disease is usually asymptomatic but leads to high mortality due to the risk of artery rupture.

Mechanosignals in abdominal aortic aneurysms

Cumulative evidence has shown that mechanical and frictional forces exert distinct effects in the multi-cellular aortic layers and play a significant role in the development of abdominal aortic aneurysms (AAA). These mechanical cues collectively trigger signaling cascades relying on mechanosensory cellular hubs that regulate vascular remodeling programs leading to the exaggerated degradation of the extracellular matrix (ECM), culminating in lethal aortic rupture. In this review, we provide an update and summarize the current understanding of the mechanotransduction networks in different cell types during AAA development. We focus on different mechanosensors and stressors that accumulate in the AAA sac and the mechanotransduction cascades that contribute to inflammation, oxidative stress, remodeling, and ECM degradation. We provide perspectives on manipulating this mechano-machinery as a new direction for future research in AAA.