Impaired Exercise Capacity and Mortality Risk in Adults With Congenital Heart Disease.

Background: An association between impaired exercise capacity and risk of mortality has been reported among adults with congenital heart disease (CHD). Over the years, treatment methods have improved and may influence outcome. Hence, we report data from a national cohort reflecting a contemporary population.
Objectives: The purpose of this study was to investigate the association between exercise capacity (workload) and mortality in a large registry-based cohort.
Methods: Data on exercise capacity using cycle ergometer were retrieved from the national registry of CHD. The association between predicted exercise capacity (%EC _pred ) and mortality was analyzed using Cox regression.
Results: In total, 3,721 adults (>18 years, 44.6% women) with CHD were included. The median age was 27.0 years (IQR: 20.8-41.0 years) and mean %EC _pred was 77% ± 20%. Over a mean follow-up of 9.4 ± 6.0 years, there were 214 (5.8%) deaths. The Multivariable Cox regression model showed that moderately and severely impaired exercise capacity (50-<70 %EC _pred : HR: 2.1, 95% CI: 1.4-3.2, P  < 0.001, and <50 %EC _pred : HR: 3.5, 95% CI: 2.1-6.0, P  < 0.001) and CHD complexity were associated with higher mortality (moderate complexity: HR: 1.9 95% CI: 1.2-3.0, P  = 0.003, great complexity: HR: 2.3 95% CI: 1.3-4.2, P  = 0.008) when adjusted for New York Heart Association class, physical activity, cardiovascular medication, sex, impaired systemic ventricular function, and age.
Conclusions: Impaired exercise capacity and CHD complexity are independently associated with all-cause mortality in patients with CHD. Exercise capacity is an easily accessible variable that may be a useful tool for risk assessment in adult patients with CHD, but this needs confirmation in prospective studies.
Competing Interests: This study is supported by grants from the 10.13039/501100003793Swedish Heart-Lung Foundation (20100355, 20130472, 20170483, 20190525, 20200493), the research foundation of health care professions within cardiology, 10.13039/501100004885Umeå University, 10.13039/501100014689Region Västerbotten (the County of Västerbotten), Heart Foundation of Northern Sweden and Visare Norr. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(© 2023 The Authors.)