A 54-year-old man is evaluated during a routine examination. He is asymptomatic, and he exercises regularly without any limitations. Medical history is significant for hypertension and a bicuspid aortic valve with an enlarged aortic root (measuring 5.1 cm 6 months ago). Family history is unremarkable. His only medication is losartan.
On physical examination, blood pressure is 122/74 mm Hg. Cardiac examination reveals a midsystolic ejection click and a grade 2/6 crescendo-decrescendo systolic murmur at the second right intercostal space. The remainder of the examination is unremarkable.
Transthoracic echocardiogram shows normal left ventricular function and a bicuspid aortic valve. The mean gradient across the aortic valve is 20 mm Hg, and the aortic valve area is 1.6 cm2. The ascending aorta is 5.1 cm; the descending thoracic aorta is incompletely visualized.
Which of the following is the most appropriate management?
A. Aortic valve replacement and ascending aortic repair
B. Ascending aortic repair
C. Dobutamine stress echocardiography
D. Repeat echocardiography in 6 months
MKSAP Answer and Critique
The correct answer is D. Repeat echocardiography in 6 months. This content is available to MKSAP 18 subscribers as Question 57 in the Cardiovascular Medicine section. More information about MKSAP is available online.
The most appropriate management of this patient with an ascending thoracic aortic aneurysm and a bicuspid aortic valve is repeat echocardiography in 6 months. Patients with a bicuspid aortic valve are prone to enlargement of the ascending aorta, and patients with both a bicuspid aortic valve and enlarged aortic dimensions are at higher risk for aortic dissection. Surveillance echocardiography should be performed in these patients to monitor aortic growth. Patients with a bicuspid aortic valve and a thoracic aortic aneurysm should undergo annual imaging if the aortic diameter has been stable and smaller than 4.5 cm. If the aortic diameter is 4.5 cm or larger or the rate of enlargement exceeds 0.5 cm/year, imaging should be performed every 6 months.
Operative aortic valve repair or replacement is indicated in asymptomatic patients with a bicuspid aortic valve and a thoracic aortic aneurysm diameter of 5.5 cm or larger, according to American College of Cardiology/American Heart Association guidelines. However, surgical intervention can be beneficial in those patients with a bicuspid aortic valve, thoracic aortic aneurysm diameter of 5.0 cm or larger, and an additional risk factor for dissection/rupture (such as family history of aortic dissection or aortic growth rate ≥0.5 cm/year). In this asymptomatic patient with an ascending aortic diameter of 5.1 cm without additional risk factors, it is premature to repair or replace the aorta.
Some patients with reduced left ventricular (LV) function and calcific aortic stenosis have severe aortic stenosis based on valve area but a gradient that is less than 30 mm Hg. Whether symptoms in this “low-flow/low-gradient” aortic stenosis are caused primarily by aortic valve disease with resultant LV dysfunction or the effective valve area is reduced owing to poor leaflet excursion can be best determined with dobutamine stress echocardiography. In this patient, there is no indication to perform dobutamine stress echocardiography, as he has normal LV function.
- Patients with a bicuspid aortic valve and a thoracic aortic aneurysm should undergo echocardiography every 6 months if the aortic diameter is larger than 4.5 cm or the rate of enlargement exceeds 0.5 cm/year.