Objectives: This study was designed to describe the experience of our center with the safety and feasibility of dobutamine stress echocardiography (DSE) in aortic stenosis (AS), to characterize the hemodynamic response to dobutamine infusion, and to examine the hemodynamic response in relation to the anatomic evaluation of the valve among patients who underwent valve replacement.
Background: The diagnosis of the hemodynamic severity of AS can be difficult when the cardiac output is reduced and the gradient is low, but the effective valve area calculates to be small. DSE has been proposed as a means of assessing the severity of AS in this setting.
Methods: We reviewed 27 patients (18 men, 9 women; mean age 71 +/- 12 years) with AS who underwent DSE between 1991 and 1996.
Results: Fifteen (55%) patients were New York Heart Association class III or IV, 8 (30%) had angina Canadian class III or IV, and 3 (11%) syncope. Dobutamine peak dose was 27 +/- 11 micrograms/kg/min. Sixteen (59%) patients had mild side effects. DSE resulted in a significant increase in the cardiac output from 4.1 +/- 1.2 L/min at rest to 7.3 +/- 1.9 L/min at peak dose, and in heart rate (76 +/- 16 beats/min to 124 +/- 20 beats/min), systolic blood pressure (128 +/- 26 mm Hg to 137 +/- 26 mm Hg), ejection fraction (38% +/- 20% to 42% +/- 20%), and transvalvular mean gradient (28 +/- 10 mm Hg to 39 +/- 9 mm Hg) (P <.05). There was also a significant increase in the valve area from 0.77 +/- 0.14 cm2 at rest to 0.97 +/- 0.21 cm2 (P <.001). Seven patients underwent surgery; all valves were severely calcified, confirming anatomic disease. In this group, an increase in the mean gradient but also a trend toward an increase in the valve area were noted in response to dobutamine: 33 +/- 10 mm Hg to 47 +/- 6 mm Hg and 0.79 +/- 0.11 cm2 to 0.95 +/- 0.19 cm2, respectively.
Conclusion: Although more data are needed to fully establish the safety of the test in this indication, this study suggests that patients with AS can safely undergo DSE. Dobutamine results in an increase not only in the mean gradient, but also in the valve area. An increase in valve area with dobutamine was observed in some patients with anatomically confirmed severe AS and thus does not exclude fixed valve disease.