PMID: 9183723May 1, 1997Paper

Use of dobutamine stress echocardiography in assessing mechanical aortic prostheses: comparison with exercise echocardiography

The Journal of Heart Valve Disease
M ZabalgoitiaR A O'Rourke

Abstract

Relatively high resting flow velocities are occasionally seen in asymptomatic patients with apparently normal mechanical aortic prostheses. Doppler echocardiography in conjunction with bicycle exercise or dobutamine have been used to 'unmask' symptoms or abnormal hemodynamics in these patients. The aim of this study was to compare the Doppler-derived hemodynamic response to exercise and to dobutamine in patients with normally functioning mechanical aortic prostheses. Bicycle ergometry (from 200-400 kg x m/min) and dobutamine (from 5-40 micrograms/kg/min) in conjunction with Doppler echocardiography were performed in 25 asymptomatic patients (21 men, four women; mean age 61 years) with mechanical aortic prostheses (range: 19 mm to 27 mm) who had normal resting hemodynamics and normal left ventricular function. Aortic valve area (continuity equation) and maximal instantaneous and mean gradients were estimated at rest and at peak stress. Target heart rate was achieved in 10/25 (40%) patients with exercise, and in 21/25 (84%) with dobutamine (p < 0.005). At peak stress, exercise induced a 25% increase in peak flow velocity, a 55% increase in valve gradients, and no significant change in valve area. In comparison, dobutamine induced...Continue Reading

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