RESUMO
Objective To investigate the effect of patent ductus arteriosus(PDA)on myocardial injury of premature infants.Methods From May 1,2010 to January 31,2011,110 preterm infants with gestational age from 28 to 36 weeks accepted echocardiography examination,and their blood samples were collected to determine cardiac troponin T(cTnT)and creatine kinase MB isoenzyme (CK-MB)levels 72 h and 3 d after deliveries.All subjects were divided into two groups according to the echocardiogram results:PDA group(n=44)and control group(n=66).The infants with PDA were treated with ibuprofen,and then echocardiography was taken again.cTnT and CK-MB were re-measured in both groups.Chi-square test,t-test,multi-variate linear regression and Spearman rank correlation test were perfomed for statistical analysis.Results Before treatment,cTnT[(0.259±0.134)μg/L]and CK-MB[(7.31± 2.69)μg/L]level of PDA group were significantly higher than those[(0.083±0.054)μg/L and(5.71±1.88)μg/L]of control group(t=9.557 and 2.588,P＜0.01 and ＜0.05,respectively).For 34 infants with successful treatment,cTnT and CK-MB levels decreased markedly to(0.062 ± 0.039)μg/L and(5.34 ± 1.50)μg/L,respectively(t =9.268 and 5.974,all P＜0.05),compared with those levels before treatment.For the ten infants failed to close ductus,the cTnT and CK-MB levels[(0.193±0.049)μg/L and(6.93±1.63)μg/L,respectively],were lower than those before treatment(t=1.525 and 0.766,all P＞0.05),while higher than those of the control group(t=9.068 and 4.055,P＜0.05).Level of cTnT positively related to the duration of ventilation,PDA and respiratory distress syndrome,while did not relate to gender,gestational age and birth weight.CK-MB level was associated to gender,gestational age,birth weight,duration of ventilatory support and PDA.In PDA group,the cTnT level was positively related to the diameter of the ductus,but not related to any indicators in echocardiography.Conclusions Symptomatic PDA could cause myocardial injury in preterm infants.The changes of blood cTnT and CK-MB were consistent with the severity of PDA.Serial measurements of blood cTnT and CK-MB might help to make early diagnosis and treatment for premature infants with PDA and myocardial injury.