Wednesday, January 6, 2010
January 5th - MHH - Aortic Stenosis
Predisposing conditions: Most common cause is calcific disease of the normal trileaflet valve, but patients with congenital bicuspid valves also get AS. Patients with this congenital condition usually present earlier, usually between ages 40-60, as opposed to those with calcific disease who presents after 60. Rheumatic fever is a cause as well, but rarely without involvement of mitral valves. Also, keep in mind that patients with AS commonly have concurrent coronary artery disease. Patients with Heyde's syndrome, associated with acquired von Willebrand syndrome, can have AV Malformations and GI Bleeds in association with Aortic Stenosis.
Clinical presentation: In the earlier stage of the disease, patients can present with exercise intolerance and fatigue. Remember the triad of Angina, Syncope and LV Failure. These symptoms also portend prognosis, with medical treatment leading to survival rates of about 5 years with angina, 3 years with syncope, and 2 years with LVF.
Physical Exam: The murmur is a harsh mid-late systolic cresendo-decresendo (i.e. "diamond shaped" murmur) at the RUSB or suprasternal notch. It can radiate into the carotids. The carotids develop a slow upstroke. The aortic component of the 2nd heart sound is usually diminished, and as the condition gets worse, A2 can disappear. Also, due to radiation of the murmur, some elderly patients may have the highest intensity at the apex. Overall, the murmur intensity decreases with Valsava and intensifies with squatting. An S4 is usually present, and a click may be present in those with bicuspid valves.
Diagnosis: Doppler is needed, and used to classify based on severity (the valve area is probably all you need to know for boards!). Patients also need repeat TTE's yearly, sometimes more frequently if severe dz present.
Severity Mean gradient (mm Hg) Aortic valve area (cm2)
Mild < 25 >1.5
Moderate 25-50 1-1.5
Severe >50 <1
Critical >80 <0.5
Medications: Judicious use of diuretics if patient has symptoms of volume overload, but this can cause problems in patients with severe disease. Same with afterload reduction - use carefully. Treat HTN with usual agents. Some studies have shown that "statins" reduce the progression of the disease.
Surgery (i.e. aortic valve replacement) is recommened for:
-Severe AS with Depressed EF
-Patients that have symptoms (angina, syncope, NYHA II or greater)
-Asymptomatic and needs other surgery (i.e. CAGB)
SO... what is aortic sclerosis? Patients with this condition have a thickened valve but without outflow obstruction. Therefore, they are usually asymptomatic - although the murmur findings are very similar to aortic stenosis, so it is hard to distinguish on physical exam.