An aortic coarctation aneurysm, also known as an aortic coarctation hematoma (aortic coarctation for short), is not really a tumor, but simply protrudes outward like a lump. It is a fatal condition in which circulating blood leaks into the aortic coarctation and forms a hematoma. The degenerative lesion of the middle layer of the aorta or cystic necrosis of the middle layer is the basis of the pathogenesis. The general pathogenesis is through two ways: First, the aortic trophoblastic vessel pressure is elevated and rupture bleeding leads to separation of the aortic intima; second, due to the elevated intra-aortic pressure, especially in elderly people with low aortic elasticity, the intima ruptures and blood enters through the rupture portal, causing the intima to split and accumulate blood to form a hematoma.