The most appropriate next step in management is to repeat the echocardiogram in 1 year. This patient has a bicuspid aortic valve and is asymptomatic. Patients with a bicuspid aortic valve should undergo surveillance transthoracic echocardiogram imaging of the aortic valve, aortic root, and ascending aorta to exclude aortic valve pathology and ascending aortic aneurysm, which are commonly associated with a bicuspid aortic valve and may be independent of the degree of aortic valve disease. This patient has mild aortic valve stenosis and a slightly dilated ascending aorta. If the aortic root or ascending aortic diameter is greater than 4.5 cm, reimaging should be performed annually. In those with an aortic diameter between 4.0 cm and 4.5 cm, the examination interval depends on the rate of progression of dilation and the family history.

Aortic valve replacement is recommended in asymptomatic patients with severe aortic valve stenosis, generally defined as a valve area below 1 cm², who may be at high risk without surgery. This patient does not have severe aortic valve stenosis, so aortic valve replacement is not necessary at this time.

Surgery to repair or replace the ascending aorta in adults with a bicuspid aortic valve is recommended when the ascending aorta diameter is greater than or equal to 5.5 cm or progressive dilatation occurs at a rate of 0.5 cm per year or greater.

Medical therapy has not been shown to reduce the rate of progression of aortic dilation in patients with aortopathy associated with bicuspid aortic valve. In patients with hypertension, control of blood pressure is essential. β-Blockers and angiotensin receptor blockers have conceptual advantages to reduce the rate of aneurysm progression but have not been shown to be beneficial in clinical studies.