Abstract: Objective To explore the relationship between platelet-related parameters and patent ductus arteriosus (PDA) in premature infants. 
Methods A total of 54 children with preterm PDA admitted to our hospital were selected as the research subjects and set as the observation group. In addition, 54 premature infants who were delivered in our hospital during the same period without PDA were selected as control group. The basic information of premature infant and puerperants (gestational age, sex, birth weight, and Apgar score, hospitalization days, maternal age, number of births, mode of delivery, presence or absence of gestational hypertension, presence or absence of gestational diabetes, and prenatal use of magnesium sulfate) were collected in the two groups. In addition, 2 mL of radial artery blood was taken from both groups of premature infants at three days after birth (the first time) and on the day of diagnosis of PDA by ultrasound (the second time). Platelet count (PLT), mean platelet volume (MPV), platelet hematocrit (PCT), and platelet distribution width (PDW) were detected. Finally, receiver operating characteristic (ROC) curve was used to analyze the value of PLT, MPV and PCT in predicting the occurrence of PDA in premature infants. 
Results There was no significant difference between two groups in terms of maternal age, number of births, mode of delivery, hypertension complicating pregnancy, complicated diabetes, sex of premature infants, Apgar score, days of hospitalization, PDW level measured for the first time and the second time (P＞0.05). The proportion of pregnant women in the observation group using magnesium sulfate before delivery was significantly higher than that in the control group, while the gestational age, birth weight, as well as PLT, MPV, and PCT of premature infants measured for the two times in the observation group were significantly lower than those in the control group (P＜0.05). ROC analysis confirmed that PLT, MPV and PCT could all be used to predict the occurrence of PDA in premature infants. The area under the ROC curve was 0.802, 0.806 and 0.859, respectively (all P＜0.05). 
Conclusion Compared with preterm infants without PDA, the platelet parameters in preterm PDA infants was significantly abnormal. The ROC analysis has confirmed that PLT＜195.805×109/L, MPV＜10.600 fL and PCT＜0.225% can be used to predict the occurrence of PDA in preterm infants, which warrants the attention of clinicians.

Key words: ductus arteriosus, patent, platelet count, mean platelet volume