Davies M W, Betheras F R, Swaminathan M
Division of Neonatal Services, Royal Women's Hospital, Melbourne, Australia.
Arch Dis Child Fetal Neonatal Ed. 2000 May;82(3):F195-9. doi: 10.1136/fn.82.3.f195.
To compare the transductal velocity ratio (TVR) of the persistent ductus arteriosus (PDA) with other echocardiographic criteria for haemodynamic significance of a PDA.
This was a prospective study (from January 1997 to August 1998) in the nurseries of the Royal Women's Hospital, Melbourne. Infants with a clinically suspected PDA were eligible and included if the echocardiogram showed a PDA with a structurally normal heart and the TVR had been measured. The PDA was assessed for evidence of left heart dilatation, the presence of reverse or absent diastolic flow in the descending aorta, the pattern of Doppler flow velocity waveform in the ductus arteriosus, and subjective assessment of ductal diameter on the real time image. The peak systolic velocity (PSV) was obtained from the pulmonary and aortic ends of the PDA, and the TVR calculated by dividing the PSV at the pulmonary end by the PSV at the aortic end.
Forty two infants had 59 echocardiographs with their TVR calculated. Mean (SD) birth weight was 1008 (362) g. Mean (SD) gestational age at birth was 27.4 (2.2) weeks with a mean (SD) corrected gestational age of 28.7 (2.7) weeks. The mean TVR was decreased in those infants with a high left atrial diameter/aortic diameter (LA/Ao) ratio (1.9 v 2.8, p = 0.0032) or reverse/absent diastolic flow in the descending aorta (2.1 v 3.0, p = 0.02). This difference was greater if those two criteria were combined (1.7 v 3.4, p = 0.0027). The mean TVR was decreased in infants with a wide open duct seen on two dimensional imaging (1.5 v 3.0, p < 0.0001) or pulsatile flow seen on pulsed Doppler in the PDA (1.9 v 3.4, p = 0.0001). The LA/Ao and left ventricle internal diameter/aortic diameter (LVIDd/Ao) ratios were higher in the group with a TVR < 1.8 than in the other two groups; these differences were statistically significant.
The TVR as a measure of the degree of constriction of a PDA is associated with other echocardiographic criteria for a haemodynamically significant PDA. A low TVR (signifying a poorly constricted duct) is associated with echocardiographic features of a significant left to right shunt, and vice versa. Further research is required to determine the usefulness of the TVR in predicting closure or likely continuing patency of a PDA and the need for treatment.
比较持续性动脉导管未闭（PDA）的经导管速度比值（TVR）与其他用于评估PDA血流动力学意义的超声心动图标准。
这是一项前瞻性研究（1997年1月至1998年8月），在墨尔本皇家妇女医院的新生儿病房进行。临床怀疑患有PDA的婴儿，若超声心动图显示为PDA且心脏结构正常，并已测量TVR，则符合入选标准并被纳入研究。对PDA进行评估，观察左心扩大的证据、降主动脉舒张期血流逆转或消失情况、动脉导管内多普勒血流速度波形模式以及实时图像上导管直径的主观评估。从PDA的肺动脉端和主动脉端获取收缩期峰值速度（PSV），并通过将肺动脉端的PSV除以主动脉端的PSV来计算TVR。
42例婴儿进行了59次超声心动图检查并计算了TVR。平均（标准差）出生体重为1008（362）g。平均（标准差）出生孕周为27.4（2.2）周，平均（标准差）矫正孕周为28.7（2.7）周。左心房直径/主动脉直径（LA/Ao）比值高或降主动脉舒张期血流逆转/消失的婴儿，其平均TVR降低（分别为1.9对2.8，p = 0.0032；2.1对3.0，p = 0.02）。若将这两个标准结合起来，差异更大（1.7对3.4，p = 0.0027）。二维成像显示导管开放较大或PDA脉冲多普勒显示有搏动性血流的婴儿，其平均TVR降低（分别为1.5对3.0，p < 0.0001；1.9对3.4，p = 0.0001）。TVR < 1.8的组中，LA/Ao和左心室内径/主动脉直径（LVIDd/Ao）比值高于其他两组；这些差异具有统计学意义。
TVR作为衡量PDA狭窄程度的指标，与其他用于评估血流动力学意义显著的PDA的超声心动图标准相关。低TVR（表示导管狭窄不良）与左向右分流显著的超声心动图特征相关，反之亦然。需要进一步研究以确定TVR在预测PDA闭合或可能持续开放以及治疗需求方面的实用性。
