Thoracic aortic aneurysm and dissection: Similarities, differences and pharmacotherapy

Aortic aneurysms and aortic dissections are major diseases affecting the thoracic aorta, with high morbidity and mortality. Thoracic aortic aneurysm (TAA) is characterized by bulge in the weakened aortic wall, which is usually asymptomatic and discovered incidentally during physical examination. Without timely intervention, approximately 50% of patients with TAA progress into aortic dissection. Thoracic aortic dissection (TAD) involves false lumen propagation from aortic intimal tear, with concomitant severe lancinating pain in the chest or back. TAA & TAD are highly similar in classification, predisposed sites, risk factors and causes, owing to the occurrence in the same segment of the aorta. Consequently, the collective term "thoracic aortic aneurysm and dissection (TAAD)" has been frequently used, and the definition of TAA & TAD is deemed interchangeable. However, TAA & TAD have essential differences in etiological causes and pathogenetic mechanisms. The mainstay treatment modalities of TAAD are open surgery or thoracic endovascular aortic repair, whereas targeted pharmacotherapies that can slow down, stop or reverse disease progression are lacking. This review summarizes the current knowledge in key aspects that aid in screening, surveilling, diagnosing and managing TAAD, and discusses similarities and differences between TAA and TAD, as well as pertinent pharmacotherapies.