Introduction: echocardiographic evaluation in neonates with persistent pulmonary artery hypertension is often limited to pressure measurements and analysis of pulmonary artery blood flow. The prognostic significance of a more detailed analysis, in particular of the extra-pulmonary shunt, is not known.
Patients and method: we analysed retrospectively the echocardiographs of neonates with persistent pulmonary artery hypertension who were also entered in a randomised therapeutic trial of treatment with inhaled nitric oxide. Our aim was to identify the predictive echographic factors for extra-corporeal circulatory assistance, death and a good response to nitric oxide.
Results: out of the 85 neonates studied, an extra-pulmonary right-left shunt across the foramen ovale or the ductus arteriosus was present in 80 patients (94%). Biventricular function was normal in the majority of patients while the cardiac index was reduced (< 2L/min/m2) in 61% of cases. With multivariate analysis, an exclusively right-left ductal shunt was a predictive factor for death (odds ratio 7.8; 95% confidence interval 1.2 to 52.8; p=0.04) while an exclusively left-right ductal shunt was at the limit of significance for circulatory assistance (odds ratio 0.13; 95% confidence interval 0.01 to 1.22; p=0.07). In the 40 patients randomised to receive nitric oxide, 28 responded positively with a reduction of at least 20% in the oxygenation index measured by post-ductal arterial gasometry. The existence of a left-right atrial shunt increased the risk of a poor response to nitric oxide (odds ratio 7.46; 95% confidence interval 1.23 to 45.1; p=0.028).
Conclusion: precise echocardiographic evaluation of these patients allows identification of prognostic factors and adjustment of vasodilator treatment.