RESUMO
BACKGROUND: Risk stratification in asymptomatic patients with severe aortic stenosis (AS) is based on exercise test results. However, differentiating between pathological and physiological breathlessness during exercise is sometimes challenging. Cardiopulmonary exercise testing (CPET) may improve quantification of cardiopulmonary exercise capacity in patients with valve diseases. AIMS: To assess the ability of CPET to detect abnormal responses to exercise and a clinical endpoint (occurrence of European Society of Cardiology guidelines surgical class I triggers). METHODS: Forty-three consecutive patients (mean age 69±13 years; 31 men) with no reported symptoms and severe AS (aortic valve surface area<1 cm2 or indexed aortic valve surface area ≤0.6 cm2/m2) prospectively underwent symptom-limited CPET. RESULTS: Twelve (28%) patients had an abnormal exercise test (AET) with symptoms (abnormal dyspnoea n=11; angina n=1). Both VE/VCO2 slope>34 (hazard ratio [HR]=5.76, 95% confidence interval [CI] 1.086-30.587; P=0.04) and peak VO2≤14 mL/kg/min (HR 6.01, 95% CI 1.153-31.275; P=0.03) were independently associated with an AET. Furthermore, VE/VCO2 slope>34 (HR 3.681, 95% CI 1.318-10.286; P=0.013) and peak VO2≤14 mL/kg/min (HR 3.058, 95% CI 1.074-8.713; P=0.036) were independent predictors of reaching the clinical endpoint. CONCLUSIONS: Cardiopulmonary exercise testing is a useful tool for characterizing breathlessness during an exercise test in apparently asymptomatic patients with AS. Peak VO2≤14 mL/kg/min and VE/VCO2 slope>34 were associated with an AET and the occurrence of European Society of Cardiology guideline surgical class I triggers.