The Washington Manual of Medical Therapeutics helps you diagnose and treat hundreds of medical conditions. Consult clinical recommendations from a resource that has been trusted on the wards for 50+ years. Explore these free sample topics:
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- Aortic stenosis (AS) is the most common cause of LV outflow tract obstruction.
- Other causes of obstruction occur above the valve (supravalvular) and below the valve (subvalvular), both fixed (i.e., subaortic membrane) and dynamic (i.e., hypertrophic cardiomyopathy with obstruction).
- Aortic sclerosis is thickening of the aortic valve leaflets that causes turbulent flow through the valve and a murmur but no significant gradient; over time, it can develop into AS.
- Most common cause in United States.
- Trileaflet calcific AS usually presents in the seventh to ninth decades (mean age, mid-70s).
- Risk factors similar to coronary artery disease (CAD).
- Occurs in 1–2% of population (congenital lesion).
- Usually presents in the sixth to eighth decades (mean age, mid–late 60s).
- Approximately 50% of patients needing aortic valve replacement (AVR) for AS have a bicuspid valve.
- More prone to endocarditis than trileaflet valves.
- Associated with aortopathies (i.e., dissection, aneurysm) in a significant proportion of patients.
- More common cause worldwide; much less common in the United States.
- Usually presents in the third to fifth decades.
- Almost always accompanied by MV disease.
The pathophysiology for calcific AS involves both the valve and the ventricular adaptation to the stenosis. Within the valve (trileaflet and bicuspid), there is growing evidence for an active biologic process that begins much like the formation of an atherosclerotic plaque and eventually leads to calcified bone formation (Figure 6-1).