Patients with aortic stenosis (AS) referred for exercise echocardiography (ExE) might have worse outcome. We aimed to assess the impact of non-severe AS on outcome in patients with a clinically indicated ExE study.
Methods: Retrospective analysis of prospectively collected data on 12,615 patients with a first treadmill ExE performed in our center. Exclusion criteria were ≥moderate aortic regurgitation, significant mitral valve disease, cardiomyopathy, congenital heart disease, and age <18 year-old. Ischemia was defined as a Δ in wall motion score index (WMSI) from rest to exercise; abnormal ExE as exercise WMSI>1.0. End points were major cardiac events (MACE) defined as cardiac death or non-fatal myocardial infarction or aortic valve replacement (AVR), either before any revascularization procedure; and overall mortality.
Results: A total of 330 patients had AS (2.6%; mild in 190, moderate in 140). Patients with AS had worse clinical characteristics (higher age, prevalence of coronary risk factors, % with typical angina, atrial fibrillation, abnormal resting ECG, history of coronary disease, and taking cardiovascular medications) and worse exercise testing characteristics (lower systolic blood pressure and heart rate at exercise, less achieved workload, and more frequency of symptoms and positive ECG) than those without AS. ExE showed more frequently abnormal ExE results and ischemia in those with AS (53% vs. 42%; and 47% vs. 30%; both p<0.001). Left ventricular ejection fraction and WMSI at peak exercise were also worse in them (59±14 vs. 62±13, p<0.001; and 1.29±0.39 vs. 1.22±0.34, p=0.001). During follow-up (Median 3.2 years, 25–75th percentiles=0.12–8.0 years) there were 1,394 MACE and 2,575 deaths. The annualized MACE rates were 17.0% in moderate AS, 6.5% in mild AS, and 2.8% without AS (p<0.001). After adjustment for clinical characteristics and resting and exercise echocardiography, the presence of AS was an independent predictor of MACE (Hazard ratio [HR]=1.99, 95% Confidence Interval [CI]=1.77–2.24, p<0.001). Any of the exercise echocardiography variables increased further the power of the model for predicting MACE: ΔLVEF, peak LVEF, ΔWMSI, ischemia, and abnormal (all p<0.001). AS was also an univariate predictor of mortality (HR=1.28, 95% CI=1.13–1.44, p<0.001), although it was not after adjustment.
In conclusion, patients with symptomatic non-severe AS have more frequently abnormal ExE studies and are at a higher risk of major cardiac events. The presence of non-severe AS is an independent predictor of events in patients referred for ExE.