Characteristics of the pulmonary circulation in infants with complete atrioventricular septal defect.

Infants with complete atrioventricular septal defect occasionally accompany pulmonary hypertension; however, the pulmonary circulation can be altered by pulmonary vascular conditions as well as the left heart lesions. This study aimed to explore whether the left heart lesions were related to the pulmonary circulation among them. We performed echocardiography and cardiac catheterisation in 42 infants with complete atrioventricular septal defect and studied relationships between the pulmonary haemodynamic parameters and the left heart morphology. Age and weight at preoperative evaluation were 65 days (47-114) (the median following interquartile range) and 5.5 kg (4.0-7.1), respectively. There were 27 individuals with Down syndrome. Gestational age was 38 weeks (37-39). Catheterisation showed mean pulmonary arterial pressure: 36 (29-46) mmHg, the ratio of pulmonary to systemic blood flow: 3.45 (2.79-4.98), pulmonary vascular resistance: 2.20 Wood units·m2 (1.53-3.65), and pulmonary arterial compliance: 2.78 (1.86-4.10) ml/Hg/m2. Echocardiography showed the Rastelli classification type A in 28 and type C in 14, moderate or severe left atrioventricular valve regurgitation in 19 patients (45%), atrioventricular valve index of 0.67 (0.56-0.79), left ventricular end-diastolic volume z score of 4.46 (1.96-7.78), and aortic valve diameter z score of -0.70 (-1.91 to 0.20). Multivariable regression analysis revealed that preoperative pulmonary vascular resistance was significantly correlated to gestational age (p = 0.002), and that preoperative pulmonary arterial compliance was significantly correlated to gestational age (p = 0.009) and Down syndrome (p = 0.036). The pulmonary circulation does not depend upon the presence of left heart lesions but gestational age and Down syndrome in infants with complete atrioventricular septal defect.