ABSTRACT
OBJECTIVES: Previous reports indicate bone deficits in patients with Fontan circulation. However, the consequences of these deficits on bone strength and when these changes occur are unclear. AIM: To compare the tibial bone strength-strain index between young patients (6-19 years) with Fontan circulation and age- and sex-matched controls, and to determine strength-strain-index in subgroups of children (6-12 years) and adolescents (13-19 years) versus controls. METHOD: The tibia was examined with peripheral quantitative CT. Based on the assessed data, bone strength-strain index was calculated in the lateral and anterior-posterior directions. RESULTS: Twenty patients with Fontan and twenty controls (mean age 13.0 ± 4.4 years; 50% females) were examined. Patients had a lower strength-strain index in the lateral direction compared to controls (808.4 ± 416.8mm3 versus 1162.5 ± 552.1mm3, p = 0.043). Subgroup analyses showed no differences regarding strength-strain index in children (6-12 years) with Fontan circulation compared to controls. However, the adolescents (13-19 years) with Fontan circulation had lower strength-strain indexes in both the lateral and anterior-posterior directions compared to controls (1041.4 ± 299.8mm3 versus 1596.4 ± 239.6mm3, p < 0.001, and 771.7 ± 192.4mm3 versus 1084.9 ± 215.0mm3, p = 0.004). When adjusted for height, there were differences between patients (6-19 years) and controls in strength-strain indexes in both the lateral and anterior-posterior directions. In subgroup analyses, the results remained robust. CONCLUSION: Young patients (6-19 years) with Fontan circulation have a lower strength-strain index in the tibia compared to controls. Subgroup analyses show that this deficit is mainly driven by the differences in adolescents (13-19 years), which might suggest that bone strength decreases with age.
ABSTRACT
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 (%ECpred) 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 %ECpred 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 %ECpred: HR: 2.1, 95% CI: 1.4-3.2, P < 0.001, and <50 %ECpred: 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.