Aortic Dissection

An aortic dissection is a tear in the wall of the blood vessel. This allows blood to flow between the layers of the blood vessel. This can lead to further complications, such as pushing on other branches of the aorta, aneurysm and loss of blood flow to areas of the body beyond the dissection.  

Acute aortic dissection is when additional dissections occur within two weeks of the original dissection. 

Chronic aortic dissection is when additional dissections occur after the two weeks following the original dissection. 

Both acute and chronic dissections require careful monitoring. Acute aortic dissections may require emergency treatment depending on the severity, as they are more prone to rupturing. 

Sources:  
MedlinePlus: Aortic dissection
NYU Cardiac and Vascular Institute