Ascending aorta 40mm is usually serious because the inner diameter of normal ascending aorta is usually below 35mm. Widening of the ascending aorta can easily cause aortic valve insufficiency and ascending aortic aneurysm and other hazards, and in serious cases, it can lead to pulmonary edema, shock and hemorrhage, etc., so it needs to be dealt with in time. 1. 40mm ascending aorta can cause aortic valve closure insufficiency, which is mostly seen in patients with long-term chronic hypertension. Long-term chronic hypertension will lead to the phenomenon of widening of the ascending aorta due to the increase of intra-arterial pressure, which will lead to aortic valve closure insufficiency, acute pulmonary edema and acute left heart failure, and need timely treatment. 2. Widening of the ascending aorta can also cause ascending aortic aneurysm, which can rupture the aneurysm resulting in hemorrhage, shock and risk of death. In order to avoid further progression of the disease, cardiac ultrasound should be reviewed regularly. If the ascending aorta widens further and an aneurysm of the ascending aorta is formed, surgical treatment is required. With an ascending aorta of 40 mm, a visit to the cardiology department is recommended as soon as possible.