主动脉剥离（英语：aortic dissection；法语：dissection aortique；德语：Aortendissektion），又译为“主动脉剥离”或「心血管动脉撕裂」，是指主动脉内膜撕裂导致血液通过内膜的破口流入主动脉壁各层之间形成夹层血肿，迫使主动脉壁各层分开。主动脉剥离是一种危险的急性病，即使及时进行积极的治疗，仍然可能快速致死。如果主动脉夹层完全撕裂，将会迅速大规模失血导致循环衰竭而立刻死亡。主动脉夹层破裂的死亡率为80%，有50%甚至还没来得及到达医院就已经死亡。因此如果主动脉剥离达到6厘米，患者必须采取紧急手术治疗。

Aortic dissection occurs when a tear in the tunica intima of the aorta causes blood to flow between the layers of the wall of the aorta, forcing the layers apart. In most cases this is associated with severe characteristic chest or abdominal pain described as "tearing" in character, and often with other symptoms that result from decreased blood supply to other organs. Aortic dissection is a medical emergency and can quickly lead to death, even with optimal treatment, as a result of decreased blood supply to other organs, heart failure, and sometimes rupture of the aorta. Aortic dissection is more common in those with a history of high blood pressure, a known thoracic aortic aneurysm, and in a number of connective tissue diseases that affect blood vessel wall integrity such as Marfan syndrome and the vascular subtype of Ehlers–Danlos syndrome. The diagnosis is made with medical imaging (computed tomography, magnetic resonance imaging or echocardiography).