The prevalence of abnormal spirometry in children with CHD.

Background: The burden of pulmonary disease in children with CHD remains under-recognised. Studies have examined children with single ventricle and two ventricle heart disease and documented a decreased forced vital capacity. Our study sought to further explore the pulmonary function of children with CHD.

Methods: A retrospective review was performed of spirometry in CHD patients over a 3-year period. Spirometry data were corrected for size, age, and gender and analysed using z-scores.

Results: The spirometry of 260 patients was analysed. About 31% had single ventricle (n = 80, 13.6 years (interquartile range 11.5-16.8)) and 69% had two ventricle circulation (n = 180, 14.4 years (interquartile range 12.0-17.3)). Single ventricle patients were found to have a lower median forced vital capacity z-score compared to two ventricle patients (p = 0.0133). The prevalence of an abnormal forced vital capacity was 41% in single ventricle patients and 29% in two ventricle patients. Two ventricle patients with tetralogy of Fallot and truncus arteriosus had similar low forced vital capacity comparable to single ventricle patients. The number of cardiac surgeries predicted an abnormal forced vital capacity in two ventricle patients except tetralogy of Fallot patients.

Conclusion: Pulmonary morbidity in patients with CHD is common with a decreased forced vital capacity noted in single ventricle and two ventricle patients. Forced vital capacity is lower in patients with single ventricle circulation; however, two ventricle patients with tetralogy of Fallot or truncus arteriosus have similar lung function in comparison to the single ventricle group. The number of surgical interventions was predictive of forced vital capacity z-score in some but not all two ventricle patients and not predictive in single ventricle patients suggesting a multifactorial to pulmonary disease in children with CHD.