Usefulness of exercise-stress echocardiography for risk stratification of true asymptomatic patients with aortic valve stenosis

Abnormal exercise test defined as the occurrence of exercise limiting symptoms, fall in blood pressure below baseline, or complex ventricular arrhythmias is useful to predict clinical events in asymptomatic patients with aortic stenosis (AS). The purpose of this study was to determine whether exercise-stress echocardiography (ESE) adds any incremental prognostic value to resting echocardiography in patients with AS having a normal exercise response. One hundred and eighty-six asymptomatic patients with at least moderate AS and preserved LV ejection fraction (>= 50%) were assessed by Doppler-echocardiography at rest and during a maximum ramp semi-supine bicycle exercise test. Fifty-one (27%) patients had an abnormal exercise test and were excluded from the present analysis. Among the 135 patients with normal exercise test, 67 had an event (aortic valve replacement motivated by symptoms or cardiovascular death) at a mean follow-up of 20 +/- 14 months. The variables independently associated with events were: age >= 65 years [hazard ratio (HR) = 1.96; 95% confidence interval (CI): 1.15-3.47; P = 0.01], diabetes, (HR = 3.20; 95% CI: 1.33-6.87; P = 0.01), LV hypertrophy (HR = 1.96; 95% CI: 1.17-3.27; P = 0.01), resting mean gradient > 35 mmHg (HR = 3.60; 95% CI: 2.11-6.37; P < 0.0001), and exercise-induced increase in mean gradient > 20 mmHg (HR = 3.83; 95% CI: 2.16-6.67; P < 0.0001). The exercise-induced increase in transvalvular gradient may be helpful to improve risk stratification in asymptomatic AS patients with normal exercise response. These results thus suggest that ESE may provide additional prognostic information over that obtained from standard exercise testing and resting echocardiography.