The most common factor for aortic widening is high blood pressure, because chronic high blood pressure leads to higher pressure in the blood vessels, and aortic widening relieves some of that pressure. Aortic widening can also be caused by syphilis infection, but it is more common due to high blood pressure. In middle-aged and elderly people, blood pressure is controlled within 150 mmHg, and widening usually does not continue. If blood pressure continues to rise, an aortic aneurysm can form in the widened area, with the risk of rupture and hemorrhage. The reason for widening of the pulmonary artery is that the pressure in the pulmonary artery is relatively high, and the burden on the pulmonary artery is heavy, and compensatory widening occurs to relieve the pressure. However, to analyze the underlying causes, there are also congenital developmental problems that result in wider pulmonary arteries, and long-term pulmonary hypertension can also lead to widening of the pulmonary arteries. Pulmonary valve stenosis can also lead to widening of the pulmonary arteries, but the process is more prolonged, so the cause of widening of the pulmonary arteries is mainly due to secondary diseases.