162 Role of Exercise Stress Echocardiography to Predict Outcome in Asymptomatic Patients with Aortic Valve Stenosis: a Multicenter Prospective Study

Abstract

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). Whether exercise stress echocardiography (ESE) provides incremental prognostic information beyond that obtained from standard exercise testing remains uncertain. This study aimed at determine if ESE adds any incremental predictive value to resting echocardiography in the subset of patients who have a normal exercise response. In this multicenter prospective study, 186 asymptomatic patients with at least moderate AS and preserved LV ejection fraction (LVEF≥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, 65 had an event (aortic valve replacement or cardiovascular death) at a mean follow-up of 13±11 months. The independent predictors of events were: LV hypertrophy (hazard ratio [HR] = 2.49; 95% confidence interval [CI]: 1.46-4.31; P = 0.0008), resting mean gradient > 35 mmHg (HR = 3.39; 95%CI: 2.00-5.93; P <0.0001) and exercise-induced increase in mean gradient > 20 mmHg (HR = 2.35; 95%CI: 1.29-4.17; P = 0.005). The latter factor also remained an independent predictor (HR = 2.39; 95%CI: 1.28-4.35; P = 0.007) of events in the subset of patients with severe AS. 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 provides additional prognostic information over that obtained from standard exercise testing and resting echocardiography.