Causes of widening of the ascending aorta include high blood pressure, syphilis infection and aortic coarctation. 1. Hypertension: Hypertension is one of the most important factors causing widening of the ascending aorta. Due to excessive blood pressure, the pressure of blood on the blood vessel wall will increase, and in the long run, the ascending aorta will thicken its wall in order to fight against the high pressure of blood. 2. Syphilis infection: Syphilis infection in the human body may invade the aorta if it progresses to the third stage of syphilis, leading to syphilitic aortic aneurysm and widening of the ascending aorta. 3. Aortic coarctation: Aortic coarctation, also known as aortic coarctation aneurysm, is a condition in which there is a rupture in the lining of the aortic wall, and blood flows from the rupture into the middle layer of the blood vessel wall, resulting in the formation of edema and thickening of the arterial wall. The causes of the widening of the ascending aorta are more complex, once this condition exists, it is necessary to improve the relevant examination to identify the specific causes and then under the guidance of the doctor for treatment, to avoid further development of the condition, bringing irreversible damage to the body.