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Essentlals Of Diagnosis
General Considerations & Etiology
Aortic stenosis is the narrowing of the aortic valve orifice, caused by failure of the valve leaflets to open normally. This reduction in orifice area produces an energy loss as laminar flow is converted to a less efficient turbulent flow, in turn increasing the pressure work that the left ventricle must perform in order to drive blood past the narrowed valve. The concentric left ventricular hypertrophy that develops as a major compensatory mechanism helps the left ventricle cope with the increased pressure work it must perform. These factors—turbulence, energy loss, and hypertrophy—constitute the pathophysiologic underpinnings for the patient's symptoms. The disease is confirmed through history and physical examination, Doppler echocardiography, and cardiac catheterization.
Clinical Findings
A. SYMPTOMS AND SIGNS
Patients with acquired aortic stenosis present with the following classic symptoms: angina, effort syncope, and congestive heart failure. Approximately 35% of patients present with angina; 15% with effort syncope; and 50% with congestive heart failure. The onset of these symptoms heralds a dramatic increase in the mortality rate for these patients if aortic valve replacement is not performed. Symptoms are therefore the guidepost for intervention, and understanding them is key to understanding and managing the disease.
Treatment
The only effective therapy for severe aortic stenosis is relief of the mechanical obstruction posed by the stenotic valve. Figure 8–5 shows the natural course of aortic stenosis: Survivorship is excellent until the classic symptoms of angina, syncope, or congestive heart failure develop. At that point, survival declines sharply. Treatment includes such modalities as aortic balloon valvotomy, valve débridement, and valve replacement.
Prognosis
As noted earlier, the natural course and thus the prognosis of unoperated aortic stenosis are widely known. Once symptoms develop, aortic stenosis becomes a lethal disease with a 3-year mortality rate of 75%. compares the mortality rate of two groups of patients with symptomatic aortic stenosis: those who refused surgery, and patients who underwent it. The difference is dramatic. Overall, the 10-year survival rate following aortic valve replacement for pure aortic stenosis is 75%. The age-adjusted survivorship after surgery remains excellent even in octogenarians free of other cardiac or systemic diseases.
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