<prompt> Aoic dissection is associated withSystemic hypeensionCoarctation of AoaIn 1 trimester of pregnancyTakayasus aeritis  <response>: The factors that predispose to aoic dissection include systemic hypeension, a coexisting condition in 70 of patients, and cystic medial necrosis. Aoic dissection is the major cause of morbidity and moality in patients with Marfan syndrome Chap. 363 and similarly may affect patients with Ehlers-Danlos syndrome. The incidence also is increased in patients with inflammatory aoitis i.e., Takayasus aeritis, giant cell aeritis, congenital aoic valve anomalies e.g., bicuspid valve, coarctation of the aoa, and a history of aoic trauma. In addition, the risk of dissection is increased in otherwise normal women during the third trimester of pregnancy. ref:Harrison;s principles of internal medicine,ed 18,pg no 2063 