OBJECTIVETo study clinical characteristics and evaluate cardiac hemodynamic changes in premature infants with patent ductus ateriosus (PDA).

METHODOne hundred and five infants born at ≤ 34 weeks' gestational age (GA) and ≤2 000 g birth weight (BW) were prospectively enrolled, including 63 males and 42 females, and the mean GA was (31. 1 ± 1.9) weeks and BW (1 401 ± 314) g. Echocardiography was done to detect hemodynamically significant PDA (hsPDA) and to evaluate left ventricular function at 2, 3, 5 and 7 d respectively after birth. On the basis of clinical symptoms and echocardiographic outcome, all the cases were divided into 3 groups: hsPDA group (n = 34), non-hsPDA (nhsPDA) group (n = 44) and non-PDA (nPDA) group (n = 27) to survey and compare general conditions, DA diameter, shunt direction, left ventricular function and complications.

RESULTThe hsPDA group had smaller GA ((30. 5 ± 2. 1) vs. (31. 6 ± 1. 6) weeks, P = 0. 01) and greater proportion of pulmonary surfactant use and mechanical ventilation (2, 3, 5 d of birth) than the nhsPDA and the nPDA group (χ2 = 11. 62, 14. 95, 12. 73, 1:1. 59, P = 0. 00; 0. 00, 0. 01, 0. 01). Univariate and multivariate Logistic regression analysis indicated that the average length of stay (ALOS) was correlated with hsPDA (F =3. 52 and P =0. 03, OR 1. 03 and P =0. 02). The ALOS was longer in the hsPDA group than in the nhsPDA and the nPDA group ((39 ±23)vs. (30 ± 16)and(29 ±13) d, P =0.02, 0.03). There was no significant.difference in rates of mortality/giving-up of treatment among the three groups (5. 9% (2/34)vs. 0 (0/44) and 3. 7% (1/27), χ2 = 5. 26, P = 0. 06). Diastolic blood pressure and mean blood pressure were significantly lower in the hsPDA group than in the other two groups (P all <0. 05) at 2, 3 and 5 days after birth and the pulse pressure was found significantly higher in the hsPDA group than in the nPDA group at 2 d after birth. Univariate and multivariate Logistic regression analysis demonstrated that hsPDA was correlated significantly with neonatal respiratory distress syndrome (NRDS) and bronchopulmonary dysplasia (BPD) (χ2 =7. 34 and 7. 39, P = 0. 02 and 0. 02; OR = 3. 46 and 4. 01, P = 0. 04 and 0. 02). Premature infants with hsPDA had normal left ventricular fractional shortening (FS) and left ventricular ejection fraction (LVEF), although the cardiac output (CO) of left ventricle increased significantly(F = 6. 93, P <0. 01) within seven days of birth. There was no significant difference in cardiac hemodynamic parameters among closed group of hsPDA group, nhsPDA group and nPDA group simutaneously reexamined at 7th day after birth. The CO was extremely significantly different among premature infants who had different GAs and BWs. The lower the GAs and the BWs, the lower the value of CO(F =5. 16 and 14. 87, P all <0. 01). The DA diameter was reduced much more dramatically after ibuprofen treatment than before in hsPDA group(t = 5. 58, P <0. 01).

CONCLUSIONThe GA, PS use and mechanical ventilation were probably associated with hsPDA. The mean blood pressure and diastolic blood pressure were decreased and pulse pressure was increased in preterm infants with hsPDA that correlated significantly with ALOS, NRDS and BPD. In addition, increased CO values were found in hsPDA group. Oral ibuprofen administered to preterm infants for hsPDA at > 24 h of life promoted ductal closure.