Prognostic Importance of Quantitative Exercise Doppler Echocardiography in Asymptomatic Valvular Aortic Stenosis

Abstract

Background— In patients with asymptomatic valvular aortic stenosis, exercise testing may help to stratify the clinical risk. However, data are limited, and the role of quantitative exercise Doppler echocardiography has never been investigated. Methods and Results— Sixty-nine consecutive patients with severe asymptomatic aortic stenosis (aortic valve area <1 cm 2 ) who prospectively underwent quantitative Doppler echocardiographic measurements at rest and during semisupine exercise test were followed up for 15±7 months. Of these, 26 had an abnormal response to exercise [occurrence of ≥1 of the following findings: angina, dyspnea, ≥2 mm ST segment depression, or fall or small (<20 mm Hg) rise in systolic blood pressure during the test] and 18 presented cardiac events during follow-up (symptoms in 2 patients, acute pulmonary edema in 2, aortic valve replacement in 12, and cardiac death in 2). In univariate analysis, patients who had cardiac events exhibited a higher increase in both peak (29±16 versus 22±14 mm Hg; P =0.019) and mean (23±8 versus 12±7 mm Hg; P =0.000003) transvalvular pressure gradients, whereas the left ventricular ejection fraction reached at peak stress was lower. These patients experienced more frequently symptoms during exercise (14 of 18 versus 12 of 51; P =0.0008). By multivariate Cox regression analysis, independent predictors of cardiac events were as follows: an increase in mean transaortic pressure gradient by ≥18 mm Hg during exercise ( P =0.0015), an abnormal exercise test ( P =0.0026), and an aortic valve area <0.75 cm 2 ( P =0.0031). Exercise Doppler echocardiographic findings provided incremental prognostic value over resting echocardiographic and exercise electrocardiographic parameters. Conclusions— Quantitative Doppler exercise echocardiography could be useful to identify a high-risk subset of patients with asymptomatic valvular aortic stenosis and help for clinical decision making.