Evaluation of aortic valve stenosis: Role of dobutamine stress echocardiography

The combination of aortic stenosis and heart failure presents a challenge for evaluation of the aortic valve. This review focuses on the evaluation of patients presenting with severe symptomatic aortic stenosis. Particular emphasis is placed on patients having heart failure and a low gradient across the aortic valve. In these situations, dobutamine echocardiography is of particular value for separating out patients who have severe aortic stenosis with existing contractile reserve from patients who have only mild aortic stenosis but severe left ventricular dysfunction. Aortic stenosis is a common valvular disorder which can be successfully corrected by valve replacement. Severe aortic stenosis creates a significant pressure overload state causing concentric left ventricular hypertrophy as a compensatory mechanism. When stenosis becomes severe and ventricular function remains compensated, the hemodynamic abnormalities are easily recognized by the presence of an elevated transvalvular gradient, a markedly reduced calculated valve area and significantly increased valvular resistance. Once symptoms appear, prognosis is markedly reduced particularly when congestive heart failure is present. If left untreated the average life expectancy is less than 2 years as the disease progresses. Therefore, prompt and effective evaluation of the true severity of aortic stenosis and the status left ventricular function is important. When aortic stenosis is combined with symptoms of congestive heart failure the echocardiographic manifestations are highly variable. Assessment by combined echocardiography and Doppler reveal several different subgroups of patients. The various subgroups may be categorized as follows.