Introduction
Dobutamine stress echocardiography is a valuable diagnostic imaging for differentiation between true and low flow–low gradient and pseudosevere aortic stenosis. Stroke volume, peak pressure gradient (PG) and mean pressure gradient (MPG), peak velocity and effective aortic valve area (EOA) are estimated at rest and after dobutamine that is administered as continuous infusion every 3 min with stepwise increase up to 20 µg/kg/min. In pseudosevere stenosis, EOA significantly increases, while gradients remain more or less constant despite flow improvement. In contrast, in case of mild to moderate aortic stenosis, all parameters increase, while in a severe aortic stenosis, pressure gradients significantly increase, while EOA remains small.
Patients and methods
Two patients were tested, the first one was a male patient, aged 62 years, weight 72 kg, height 172 cm, and BSA 1.86 cm2, was found to have moderate aortic stenosis with low flow and low gradients. The second one was a female aged 59 years. Dobutamine stress test was done using standard protocol starting at 2.5 µg/kg/min and increasing at 3-min intervals up to maximum dosage. Monitoring with 12-lead ECG and blood pressure measurements were recorded.
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