高频超声预测早产儿动脉导管早期自然关闭的价值

目的探讨高频超声预测早产儿动脉导管早期自然关闭的价值。方法170名早产儿（孕周〈37周），均在出生后24h内入院，高频及常规超声心动图连续观察动脉导管，首次超声心动图检查于出生后24h内完成，以后每天随访观察至第7天，若此期间发现动脉导管已经闭合，则不再继续随访检查。其中16名早产儿动脉导管出生7d内未自然关闭，为动脉导管早期未自然关闭（早期PDA）组，另从7d内自然关闭组中随机选取32名早产儿作为对照组，分别采用高频探头及常规心脏探头测量动脉导管内径、左房前后径与主动脉根部内径比值（LA／AO）。结果早产儿动脉导管于24、48、72h内自然关闭率分别约18．8％（32／170）、61．2％（104／170）、78．8％（134／170），7d内达90．6％（154／170），即早产儿出生后早期动脉导管自然关闭率约90．6％（154／170）。高频超声对动脉导管二维及彩色血流长度完整显示率均高于常规超声82％（39／48）w46％（22／48），P〈0．001，100％（48／48）w77．1％（37／48），P〈0．01]，差异有统计学意义。高频超声测得早期PDA组动脉导管的内径大于对照组（2．08±O．4）mm vs （1．09±0．22）mm，P〈0．001]，以1．55mm为临界值，预测早生儿出生后7d内动脉导管自然关闭的敏感度、特异度分别为87．5％、90．6％，准确性为66．5％。结论高频超声能明确诊断早产儿PDA，在精确显示动脉导管结构上优于常规超声心动图：动脉导管内径越大，早期自然关闭可能性越小。

The value of high frequency ultrasound in predicting spontaneous closure of patent ductus arteriosus in preterm neonates

Objective To study the value of high frequency ultrasound in predicting spontaneous closure of patent duct arteriosus （PDA） in premature neonates. Methods One hundred and seventy premature neonates aged less than 37 weeks of gestation were enrolled. They were all admitted in the neonatal intensive care unit of Jinhua People＇ s Hospital within 24 hours after birth. Echocardiographic examinations was conducted using GE＇ s Vivid I Portable color Doppler ultrasonography with routine cardiac probe （frequency 1.7-3.4 MHz） and high-frequency transducer （frequency 7.5 MHz）. Up to the 7th day, the echocardiography was carried out every day after birth until the closure of PDA .They were divided to two groups according to whether spontaneous closure of PDA took place with in 7 days after birth （the control group） or not （the PDA group）. There were 16 premature neonates in PDA group, including 6 male and 10 female. The mean gestational week at birth was （35.3 4±1.4） weeks. The mean birth weight was （2 330.9 4±325.5） g. Thirty-two premature neonates were included incontrol group, including 13 male and 19 female. The mean gestational week at birth was （35.0±1.3） weeks. The mean birth weight was （2 337.54±287.8） g. The clinical characteristics and echocardiographic parameters were compared between the two groups. Results The detection rates of high-frequency ultrasound and routine echocardiography were all 100%. The spontaneous closure rate of PDA in preterm infants at 24 hours, 48 hours, 72 hours were 18.8% （32/170）, 61.2% （104/170）, 78.8% （134/170） respectively. Within 7 days after birth, the closure rate was 90.6% （154/170）, therefore the incidence of PDA in premature neonates was about 9.4% （16/170） in our study. The display rate of entire duct arteriosus using high frequency ultrasound was significantly higher than that using routine ultrasound 82%（39/48） vs 46%（22/48）, P 〈 0.001, 100%（48/48） vs 77.1%（37/48）, P 〈 0.01]. The diameters of duct arteriosus in PDA group were significantly larger than that in control group （2.08±0.4） mm vs （1.09±0.22） mm, P〈 0.001]. However, the remaining echocardiographic parameters showed no significant difference between the two groups （P 〉 0.05）. To predict the spontaneous closure of PDA in preterm neonates within 7 days after birth by high frequency ultrasound, the sensitivity, specificity and accuracy were 87.5%, 90.6% and 66.5% respectively using the cutoff point of 1.55 mm. While the sensitivity, specificity and accuracy were 75%, 93.7%, 44.15% by routine echocardiographywiththecutoffpointof2.36mm. Conclusions High-frequency ultrasound can confirm the diagnosis of PDA in preterm infants and it is better than routine echocardiography in depicting the structure of arterial duct. The larger PDA diameter was suggestive of the lower possibility of spontaneous close.