Aortic sclerosis overview

Overview
Aortic sclerosis commonly affects elderly population. Aortic sclerosis is defined based on transthoracic echocardiographic findings which include irregular leaflet thickening and focal valve thickening with associated increase in echogenicity.

Pathophysiology
Microscopic changes reveal lipoprotein accumulation, cellular infiltration and extracellular matrix formation that cause progressive thickening of the aortic valve.

Epidemiology
Aortic sclerosis is non-obstructive degeneration of the aortic valve that presents predominantly in patients over 65 years of age who have risk factors for coronary artery disease. Because aortic sclerosis is associated with coronary artery disease risk factors, it is also associated with a significant increase in the risk of cardiovascular death, myocardial infarction even in the absence of hemodynamically significant left ventricular outflow tract obstruction.

Risk Factors
The presence of aortic sclerosis has been suggested as a marker of increased cardiovascular risk, including increased mortality. However, it remains unclear whether aortic sclerosis is independently associated with risk or merely a marker of coexistent cardiovascular risk factors.

Natural History, Disease Progression & Prognosis
Calcification of the aortic valve is common among the elderly population and shares epidemiologic and histopathologic similarities to atherosclerosis. Progressive thickening and calcification of the aortic valve subsequently causes left ventricular stiffness resulting in left ventricular outflow tract obstruction, thereby leading to aortic stenosis. Prognostically, it is known that aortic stenosis is clearly associated with adverse cardiovascular outcomes; however, it is unclear whether aortic sclerosis independently increases the risk of cardiovascular events or progression of aortic sclerosis to aortic stenosis increases the risk, including mortality.

History and Symptoms

 * Mostly asymptomatic
 * Aortic sclerosis is an incidental echocardiographic finding

Physical Examination
While a short mid-systolic 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.

Echocardiography

 * Focal areas of valve thickening with associated increase in echogenicity is the hallmark of aortic sclerosis,   as opposed to the diffuse thickening observed as a part of normal aging
 * Aortic side of the valve in the center of the valve cusp is commonly affected
 * Commissural areas are spared
 * Irregular leaflet thickening
 * Leaflet mobility is normal
 * Valvular hemodynamic parameters are normal with a jet flow velocity of less than 2.5 m per sec across the valve

Treatment

 * Aortic sclerosis has been suggested as a marker of increased cardiovascular risk, including increased mortality. Therefore, risk factor reduction among this patient population is reasonable although no definitive study has demonstrated reduction in aortic sclerosis progression achieved with aggressive management of hypertension and dyslipidemia


 * Patients with isolated aortic valve disease rarely experience embolic events, therefore, according to the 2008 ACCP guidelines no antithrombotic therapy is required for the prevention of calcific microemboli.


 * According to the 2008 ACC/AHA guidelines, no antibiotic prophylaxis is recommended for patients with aortic sclerosis.