TOC | Cardiology    AORTIC STENOSIS                 SX  |  TESTS  |  RX

The normal aortic valve is 3 to 4 cm2 in area when fully open. Aortic stenosis is considered severe when the valvular area is 1 cm2 or less and considered critical when the area is less than 0.75 cm2.  AS is rarely of hemodynamic or clinical importance until the orifice has narrowed to 1/3 of normal, i.e. to 1 cm2 in adults.

A peak systolic pressure gradient > 50 mmHg in the face of anormal cardiac output or an effective aortic orifice < 0.5 cm2/m2 of body surface area (i.e. < 1/3 of normal orifice) is generally considred to represent critical obstruction to left ventricular outflow.

Although the CO at rest is WNL in the majority of pts with severe Aortic Stenosis, it may fail to rise normally during exercise.

SX:
Exertional dyspnea, fatigue, angina, exertional syncope, LV systolic & diastolic dysfunction Sx, Pulm.hypertension Sx, & serious arrhythmia in severe aortic stenosis.

SIGNS:
Systolic murmur in aortic area with or without thrill, with radiation to the neck area; also S4.

TESTS:

• ECG: LVH changes to suggest significant aortic stenosis.
• Doppler echocardiograph: reduced opening of the aortic valv; is reduced; increased the peak velocity across the valve and thus the aortic pressure gradient; the mean pressure gradient across the valve is often 50 mm Hg or more in severe aortic stenosis.

RX:
Aortic stenosis is a progressive disease that can remain asymptomatic for many years. Once symptoms become manifest, survival without surgical treatment is reduced. Thus, mean survival in patients with angina is five years; with syncope, three years; and with heart failure, two years or less. Operative mortality increases with severe symptoms, advanced age, and the presence of left ventricular dysfunction.

The major indication for surgical intervention of aortiac stenosis:

• the onset of symptoms & left ventricular dysfunction attributable to aortic stenosis
• moderate or severe aortic stenosis at the time of bypass surgery
• asymptomatic severe aortic stenosis if patient plans pregnancy, patient desires high level of physical exertion or lives in a area remote from medical care, or elective procedure in patient with severe obstruction due to patient preferences..

REF:

Progression Cardiovascular Diseases - May/June 2001
Scientific American Medicine 1999

Current medical management of valvular heart disease  - Cleveland Clinic J Med Oct. 2001  

Caring for patients with prosthetic heart valves
Cleveland Clinic J of Med  Jan. 2002

Aortic Stenosis  (Clinical Practice)
NEJM  Feb. 28, 2002  - B.A. Carabello  
Strategies and Evidence
There is no effective medical therapy for severe aortic stenosis; aortic stenosis is a mechanical obstruction to blood flow that requires mechanical correction.
In children with congenital aortic stenosis, the valve leaflets are merely fused, and balloon valvotomy may offer substantial benefit.
In adults with calcified valves, however, balloon valvotomy only temporarily relieves symptoms and does not prolong survival.  Thus, the intervention required in adults, other than standard prophylactic antibiotics against infective endocarditis, is the replacement of the valve. The risks of replacing that valve must be weighed against the risks of delaying the procedure. The procedure can usually be delayed until symptoms develop. Studies of aortic stenosis uniformly demonstrate that once angina, syncope, dyspnea, or other symptoms of heart failure develop and are found to be due to aortic stenosis, the patient's life span is drastically shortened unless the valve is replaced . In contrast, 10-year age-corrected rates of survival among patients who have undergone aortic-valve replacement approach the rate in the normal population.

03202002