Risk factors for pulmonary artery hypertension in preterm infants with moderate or severe bronchopulmonary dysplasia.

BACKGROUND

Despite the potential importance of pulmonary artery hypertension (PAH) in preterm infants with bronchopulmonary dysplasia (BPD), little is known about the risk factors for PAH.

OBJECTIVES

To investigate the risk factors for PAH in preterm infants with BPD.

METHODS

Infants diagnosed with BPD were assigned to the PAH group or non-PAH group except for infants with mild BPD who had no PAH. PAH was diagnosed on the basis of echocardiograms demonstrating elevated right ventricle pressure beyond the postnatal age of 2 months. Logistic regression analysis was done for the multivariate assessment of the risk factors for PAH in preterm infants with moderate or severe BPD.

RESULTS

A total of 98 infants among 145 infants with BPD were divided into a PAH group (n = 25) or non-PAH group (n = 73), while the remaining 47 infants had mild BPD with no PAH. Among the study patients, survival rate of the PAH group was significantly lower than that of the non-PAH group. Infants with PAH had more severe cases of BPD and underwent longer durations of oxygen therapy, conventional or high-frequency ventilation, and hospitalization compared to those without PAH. Low 5-min Apgar scores (≤6; relative risk (RR) 6.2; 95% confidence interval (CI) 1.4-28.0; p = 0.017) and oligohydramnios (RR 7.7; 95% CI 2.0-29.6; p = 0.030) were found to be significant risk factors for PAH according to multivariate analysis.

CONCLUSIONS

The present study shows that oligohydramnios is a specific risk factor for PAH in preterm infants with moderate or severe BPD.