Aortic dissection is a tear in the wall of the aorta that causes blood to flow between the layers of the wall of the aorta and force the layers apart. Aortic dissection is a medical emergency and can quickly lead to death, even with optimal treatment. If the dissection tears the aorta completely open, massive and rapid blood loss occurs. Aortic dissections resulting in rupture have an 80% mortality rate, and 50% of patients die before they even reach the hospital. If the dissection reaches 6 cm, the patient must be taken for emergency surgery.