Is exercise testing useful to improve the prediction of coronary events in asymptomatic subjects?

Abstract

The value of exercise testing (ET) in asymptomatic subjects remains controversial and is unknown in countries with a low coronary heart disease (CHD) incidence. The aim of this study was to investigate the ability of ET to improve the prediction of a first coronary event in such a population. Using a prospective cohort study, 1051 consecutive healthy asymptomatic adults were enrolled in a cardiovascular screening program including ET. The pre-test risk of CHD was evaluated by the 10-year Framingham risk function. Positive ET was defined as a horizontal or downsloping ST-segment depression ≥ 1.0 mm. The primary outcome was total coronary events (CE) occurrence, including cardiac deaths, acute myocardial infarction and stable or unstable angina. The mean follow-up period was 6 years. Subjects were aged 18-79 years and 36% were women. A total of 89 subjects (8.5%) had a positive ET. Positive exercise testing was associated with CE occurrence in a univariate analysis only in subjects with higher pre-test risk, defined by a 10-year Framingham risk =10.4% [hazards ratio (HR) = 2.61; 95% confidence interval (CI) (1.07-6.40)]. In this risk category, ET was able to provide incremental information over the major risk factors in both men and women [risk factor-adjusted HR for positive ET = 2.86; 95% CI (1.14-7.20)]. This risk excess in subjects with positive ET persisted even when a coronary revascularization was performed. Subjects with intermediate pre-test probability (10-15%) and positive ET had a post-test probability of CE largely equivalent to the probability in subjects with known CHD. Additional informã¡tion provided by ET in subjects with a pre-test risk at 10-years =10% should lead to a more efficient use of risk-reducing therapies than it would be the case in this risk category with the analysis of traditional risk factors only. © 2006, European Society of Cardiology. All rights reserved.