Abstract 4124: Maximal Workload during Exercise Testing, Coronary Risk Evaluation and the Risk of Cardiovascular and All-Cause Death
Introduction: Cardiovascular risk factor score provides a good initial method for assessing individualized risk at low cost. However, the additional prognostic value of exercise stress test results with global cardiovascular risk evaluation systems for predicting cardiovascular disease (CVD) and all-cause mortality in asymptomatic individuals is unclear.
Methods: The study is a prospective population-based study based on 1639 men (42– 60 years) without history of type II diabetes or atherosclerotic cardiovascular disease including coronary heart disease, stroke or claudication at baseline. Exercise capacity was measured with an electrically braked cycle ergometer testing protocol comprised of an increase in the workload of 20 W per minute. During an average follow-up of 16 years, a total of 304 deaths occurred, of which 114 were due to CVD.
Results: The risk predictors for all-cause death were European risk Score (for 1 % increment, RR 1.13, 95 % CI 1.06 to 1.19, p<0.001), exercise capacity (for 20 Watts increment, RR 0.87, 95 % CI 0.83 to 0.92, p<0.001), when adjusted for age, serum high-density lipoprotein, C-reactive protein, body mass index, alcohol consumption, family history of coronary heart disease, exercise-induced ST depression and the use of medications for hypertension, dyslipidemia or aspirin. Exercise-induced ST depression was related to CVD death (RR=2.13, 95 % CI 1.20 to 3.90, p=0.01) in addition to exercise capacity and European risk Score. The risk was 2.29-fold (95 % CI 1.55 to 3.41, p<0.001) for all-cause death and 2.11-fold (95 % CI 1.16 to 3.87, p=0.015) for CVD death among men with exercise capacity less than 200 Watts (lowest quartile) as compared to those with higher than 262 Watts (highest quartile), after adjustment for age and other risk factors. The combination of exercise capacity less than 200 Watts and high Score (over 5%) was related to a 6.18-fold (95 % CI 3.36 to 11.34, p<0.001) risk of CVD death.
Conclusions: This study provides rationale for inclusion of exercise capacity testing to identify asymptomatic individuals at high risk by traditional assessment scores who might benefit most significantly by primary prevention measures.