Respiratory morbidity in children with congenital heart disease.

OBJECTIVE: To evaluate the respiratory outcome in children with congenital heart disease (CHD), considering recent management procedures and the CHD pathophysiology. DESIGN AND SETTING: Clinical and functional respiratory outcome were evaluated in 8-year-old children with isolated CHD followed up from birth in the prospective population-based EPICARD cohort. PATIENTS: Children were assigned to two groups, based on the pathophysiology of the CHD: CHDs with left-to-right shunt (n = 212) and CHDs with right outflow tract obstruction (n = 113). RESULTS: Current wheezing episodes were observed in 15% of the children with isolated CHD and left-to-right shunt, and 11% of the children with isolated CHD and right outflow tract obstruction (not significant). Total lung capacity (TLC) was the only respiratory function parameter that significantly differed between the two groups. It was lower in children with left-to-right shunt (88.72 ± 0.65% predicted) than in those with right outflow tract obstruction (91.84 ± 0.96, p = 0.006). In multivariate analysis, CHD with left-to-right shunt (coeff. [95% CI]: -3.17 [-5.45; -0.89]) and surgery before the age of 2 months (-6.52 [-10.90; -2.15]) were identified as independent factors associated with significantly lower TLC values. CONCLUSION: Lower TLC remains a long-term complication in CHD, particularly in cases with left-to-right shunt and in patients requiring early repair. These findings suggest that an increase in pulmonary blood flow may directly impair lung development.

Cardiac performance assessment during cardiopulmonary exercise test can improve the management of children with repaired congenital heart disease.

BACKGROUND: Children with repaired congenital heart disease (CHD) have impaired maximal aerobic capacity (VO2max). Determining the causes of their VO2max alteration remains challenging. Cardiac output measure using thoracic impedancemetry during cardiopulmonary exercise tests (CPET) can help to understand the determinants of VO2max in children with open-heart repaired CHD. METHOD: We analyzed CPET in 77 children with repaired CHD. Among them, 55 patients had residual lesions. Patients with repaired CHD were compared with 44 age-matched healthy individuals. Maximal oxygen content brought to capillaries (QO2max) and oxygen muscle diffusion capacity (DO2) were assessed using cardiac output measure, Fick principle and simplified Fick law. RESULTS: In the 55 patients with residual lesion, VO2max, QO2max and DO2 were lower than those of controls (76.1 vs 86% of theoretical value, p < 0.01; 2.15 vs 2.81 L/mn, p < 0.001; 24.7 vs 28.8 ml/min/mmHg, p < 0.05). Decrease in QO2max was due to both impaired stroke volume and chronotropic insufficiency (48 vs 53 ml/m2 and p < 0.05; 171 vs 185/min p < 0.001). Patients without residual lesion (22/77) had normal VO2max with lower maximal heart rate compensated by higher SV (p < 0.05). CONCLUSION: Aerobic capacity was normal in children without residual lesions after CHD repair. Patients with residual lesion have impaired VO2max due to both lower central and peripheral determinants. Measuring cardiac performance during CPET allowed a better selection of patients with altered cardiac reserve that can benefit from residual lesion treatment and find the good timing for intervention. Detection of peripheral deconditioning can lead to a rehabilitation program.