TCD Ultrasound of Subjects Enrolled in Baby HUG

描述（由申请人提供）： 婴儿TCD是婴儿HUG初始阶段的拟定辅助研究，婴儿HUG是一项由NHLBI/NIH资助的多中心临床试验（合同编号N 01-HB-07160）。 在Baby HUG中，患有镰状细胞病（SCD）的婴儿（12-17个月）将被随机分配到羟基脲（HU）或安慰剂组，并随访24个月。 人们对胡锦涛对正在研究的儿童中枢神经系统的影响产生了广泛的兴趣。 中风发生在1岁以后，有证据表明，脑血管疾病的过程在一些患者中很早就开始了。 镰状细胞病的合作研究记录了2-6岁年龄组中风的高风险。 这项辅助研究旨在探索HU如何通过使用经颅多普勒（TCD）超声作为卒中风险的生物标志物来发挥作用。 拟议的研究将在基线和研究结束时对Baby HUG中的40名儿童进行TCD检查。 TCD已被证明在估计2-16岁SCD儿童的卒中风险方面非常有用，并且是基于STOP研究的NHLBI推荐的卒中一级预防范例的中心。 如果中风风险可以在早期检测到（即，年龄小于STOP中的2-16岁受试者），那么医生将能够在疾病的早期阶段提供预防性治疗。 治疗前和治疗后24个月将进行TCD检查。 TCD表现和阅读将集中控制，并与STOP一致。 建议者具有父母研究所针对的年龄段的婴儿TCD经验。 比较HU组与对照组治疗前后TCD的变化。 此外，提案人还可以获得20世纪90年代中期至后期实施的STOP筛查计划中400多名2-4岁儿童的数据。 由于这些患者未接受HU或输血，因此该数据集将用于估计未接受HU治疗的高卒中风险的患病率，并可与Baby HUG中的HU组进行比较，为分析增加了另一个重要的比较维度。 虽然样本量按照母研究的设计故意较小，但婴儿TCD可以检测到治疗结束时高危患者患病率的巨大差异。

DESCRIPTION (provided by applicant): Baby TCD is a proposed ancillary study to the initial phase of Baby HUG, a multicenter clinical trial funded by NHLBI/NIH (Contract No. N01-HB-07160). In Baby HUG, infants (12-17 months old) with sickle cell disease (SCD) will be randomized to either hydroxyurea (HU) or placebo and followed for 24 months. There is broad interest in the effect of HU on the central nervous system in the children being studied. Stroke occurs after age 1 year and there is evidence that the process of cerebrovascular disease starts very early in some patients. The Cooperative Study of Sickle Cell Disease documented a high risk of incident stroke in the 2-6 year age group. This ancillary study proposes to explore how HU might work by using transcranial Doppler (TCD) ultrasound as a biomarker of stroke risk. The proposed study will perform TCD on the 40 children in Baby HUG at baseline and at end of study. TCD has proven very useful in estimation of stroke risk in children with SCD ages 2-16 years, and is at the center of a paradigm of primary stroke prevention recommended by NHLBI based on the STOP study. If stroke risk could be detected at an earlier stage (i.e., younger than the 2-16 year-old subjects in STOP), then physicians would be able to provide preventive treatment at an earlier stage of the disease. TCD will be performed before and after 24 months of treatment. TCD performance and reading will be centrally controlled and STOP-consistent. The proposers have experience in TCD of infants, the age targeted by the parent study. TCD will be compared between HU and control groups, before and after treatment. In addition, the proposers have access to data from over 400 children in the 2-4 year age range from the STOP screening program performed in the mid- to late 1990s. Since these patients were not on HU or transfusion this dataset will be used to give an estimate of the prevalence of high stroke risk without HU treatment, and can be compared to the HU group in Baby HUG, adding another important comparative dimension to the analyses. Although the sample size is purposely small as designed by the parent study, large differences in the prevalence of high-risk patients at the end of treatment could be detected by Baby TCD.