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Dobutamine Stress Echo: Difference between revisions
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DSE with low- gradient aortic stenosis | ==DSE with low- gradient aortic stenosis== | ||
Low-gradient aortic stenosis is defined as a severe aortic valve stenosis (AVA <1.0cm<sup>2</sup>) with a transvalvular pressure gradient ≤30mmHg. A low- gradient aortic stenosis occurs in patients who have LV dysfunction with decreased ejection fraction. The assessment of the AGM in these patients may be overestimated because the calculated AVA is proportional to the displacement. A poorly functioning LV can exert enough pressure to the calcified aortic valve to open. At a fixed, or "true" stenosis in which the stroke volume increases, the gradient across the valve also increases relatively. In some patients, an increase in stroke volume results for only a limited increase in pressure gradient across the aortic valve. This phenomenon is called a "pseudo stenosis". DSE is a tool used to make a distinction between a true stenosis and a pseudo stenosis. | |||
Patients with pseudo- stenosis manifest an increase in the calculated AGM and a decrease in resistance of the valve as a response to an increase of the stroke volume. The reaction is different in patients with severe aortic valve stenosis in whom dobutamine-induce increases transvalvular flow, giving an increase in the mean transvalvular gradient, but no change in AGM. | |||
A DSE study in a low-gradient aortic valve stenosis is given a low-dose dobutamine. That is, they start to get 5μg/kg/min and gradually increase to a maximum 20μg/kg/min. | |||
A DSE may also demonstrate a severe aortic stenosis with low transvalvular pressure gradient or contractile reserve. Contractile reserve has a predictive value for mortality in surgery of aortic valve replacement. Recent studies have shown that perioperative mortality 5-8% versus 32% without contractile reserve in contractile reserve.<cite>2</cite> | If there is an increase in stroke volume, an increase in AVA ≥0.3cm<sup>2</sup> and a small change in gradient produced after administering Dobutamine, there is an overestimation of the severity of aortic stenosis (=pseudo stenosis). | ||
A DSE may also demonstrate a severe aortic stenosis with low transvalvular pressure gradient or contractile reserve. Contractile reserve has a predictive value for mortality in surgery of aortic valve replacement. Recent studies have shown that perioperative mortality is 5-8% versus 32% without contractile reserve in contractile reserve.<cite>2</cite> | |||
==Indication DSE== | ==Indication DSE== | ||
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|Congestive heart failure | |Congestive heart failure | ||
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|Serious | |Serious tachyarrhythmia | ||
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|Serious | |Serious valve stenosis | ||
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|Hypertrophic obstructive cardiomyopathy | |Hypertrophic obstructive cardiomyopathy | ||