<prompt> Most common cause of Aoic dissection ?HypeensionDMTraumaMafan syndrome  <response>: Ans. is a i.e., Hypeensiono More than 90 of dissections occur in men between the age of 40 and 60 with antecedent hypeension. Other causes of dissection.o Marfan syndrome causing cystic medial necrosis second most common.o Ehlers - Danlos syndrome.o Inflammatory aoitis -- Takayasus disease, Giant cell aeritis.o Coarctation of aoa.o Normal woman during third trimester of pregnancy.o Congenital bicuspid aoic valve. 