Aortic stenosis differential diagnosis


 * Associate Editors-In-Chief: Mohammed A. Sbeih, M.D. [mailto:msbeih@perfuse.org]; Assistant Editor-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

Overview
Aortic stenosis must be differentiated from other cardiac or pulmonary causes of dyspnea, weakness, and dizziness. Furthermore, if there is left ventricular outflow tract obstruction, it is critical to identify if the obstruction is subvalvular, valvular or supravalvular or due to Hypertrophic Cardiomyopathy (HOCM).

Differentiating Aortic Stenosis from Pulmonary Causes of Dyspnea
AS can be differentiated from pulmonary causes of dyspnea by a narrow pulse pressure, a harsh late-peaking systolic murmur heard best at the right second intercostal space with radiation to the carotid arteries, and a delayed slow-rising carotid upstroke (pulsus parvus et tardus) and signs of heart failure on examination.

Differentiating Aortic Stenosis from Aortic Sclerosis
While a murmur may be heard in aortic sclerosis, there is no fusion of the commisures and no significant obstruction to forward flow across the aortic valve. As a result, the S2 is normal in aortic sclerosis and the carotid upstroke is normal (i.e. pulsus parvus et tardus) is absent.

Differentiating Aortic Stenosis from Mitral Regurgitation
The murmur of aortic stenosis is harsh and best heard at the right second intercostal space while the murmur of mitral regurgitation is blowing and soft and best heard at the apex.

Differentiating Aortic Stenosis from Hypertrophic Obstructive Cardiomyopathy
In HOCM the murmur is dynamic and varies with maneuvers. In HOCM there is a bifid or spoke and dome pattern to the carotid upstroke.

Differentiating Valvular Aortic Stenosis from Subvalvular Aortic Stenosis
Aortic insuffiency is more often present with subvalvular aortic stenosis (in 50% to 75% of cases). Echocardiography identifies a membrane or fibromuscular obstruction. Symptoms begin earlier in life (in childhood or adolescence) than in valvular aortic stenosis.

Differentiating Valvular Aortic Stenosis from Supravalvular Aortic Stenosis
Supravalvular aortic stenosis is an uncommon congenital anomaly produced by narrowing of ascending aorta or by fibrous diaphragm with small opening just above aortic valve. It presents in early adulthood. The aortic valve is not stenotic, but doppler shows an increased gradient. 50% of patients with supravalvular aortic stenosis have a characteristically greater pulse and systolic blood pressure in the right carotid and brachial arteries than in the left. The systolic murmur is maximal below the right clavicle and radiates primarily to the right carotid artery. There is no ejection click present, and no diastolic murmur is present.