Resting lung function in children after repair of tetralogy of Fallot.

Children with tetralogy of Fallot had pulmonary function tests (PFT) after intracardiac repair (ICR). According to the age at time of ICR and to the existence or not of palliative surgery preceding ICR, they were divided into three groups. Group 1 had ICR at a mean of one year one month of age (range four months to one year seven months), that is, during the active period of postnatal lung growth. Groups 2 and 3 had ICR later in childhood, that is, respectively, at four years seven months (range two years nine months to 11 years 9 months) and at five years four months (range two years seven months to 11 years five months). In group 3, ICR was preceded by palliative surgery. The PFT at rest included measurement of lung volumes (functional residual capacity), vital capacity (VC), dynamic or static compliance (CL), total pulmonary resistance, lung transfer factor for CO (TLCO) and blood gases. Group 1 had normal lung function suggesting that early repair of TOF saves lung development. In groups 2 and 3, significant decrease in VC(p less than 0.01) and CL (p less than 0.01) were found suggesting impaired alveolar growth. Additional defect in TLCO (p less than 0.01) in group 3 suggested that palliative surgery induces abnormal vascular growth. Thus, the present functional results suggest repair of TOF during the two first years of life, ie, the active period of postnatal lung growth.